uboot readme

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前面是 Uboot 的发展，下载地址，如何获得帮助，以及版本说明

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Directory Hierarchy:

目录层次

====================

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- board????????? Board dependent files

????????? 开发板相关文件

- common????? Misc architecture independent functions

????????? 多体系结构独立函数

- cpu???????????? ? CPU specific files

????????? CPU 相关文件

? - 74xx_7xx?????? ? Files specific to Freescale MPC74xx and 7xx CPUs

? ?? ????????????Freescale MPC74XX 的 CPU 相关文件

? - arm720t? ??? Files specific to ARM 720 CPUs

??????????????? ARM720 相关文件

? - arm920t? ??? Files specific to ARM 920 CPUs

??????????????? ARM920 相关文件

? - at91rm9200 ?Files specific to Atmel AT91RM9200 CPU

??????????????? AT91RM9200 相关

? - imx? ????? Files specific to Freescale MC9328 i.MX CPUs

????????????? Freescale i.MX 相关

? - s3c24x0? ? Files specific to Samsung S3C24X0 CPUs

? - arm925t? ? Files specific to ARM 925 CPUs

? - arm926ejs????? Files specific to ARM 926 CPUs

? - arm1136 ? Files specific to ARM 1136 CPUs

? - at32ap??? ? Files specific to Atmel AVR32 AP CPUs

? - i386 ??? Files specific to i386 CPUs

? - ixp????????? ??? Files specific to Intel XScale IXP CPUs

? - leon2????? ??? Files specific to Gaisler LEON2 SPARC CPU

? - leon3????? ??? Files specific to Gaisler LEON3 SPARC CPU

? - mcf52x2 ? Files specific to Freescale ColdFire MCF52x2 CPUs

? - mcf5227x????? Files specific to Freescale ColdFire MCF5227x CPUs

? - mcf532x ? Files specific to Freescale ColdFire MCF5329 CPUs

? - mcf5445x????? Files specific to Freescale ColdFire MCF5445x CPUs

? - mcf547x_8x?? Files specific to Freescale ColdFire MCF547x_8x CPUs

? - mips Files specific to MIPS CPUs

? - mpc5xx?? Files specific to Freescale MPC5xx? CPUs

? - mpc5xxx Files specific to Freescale MPC5xxx CPUs

? - mpc8xx?? Files specific to Freescale MPC8xx? CPUs

? - mpc8220?????? Files specific to Freescale MPC8220 CPUs

? - mpc824x?????? Files specific to Freescale MPC824x CPUs

? - mpc8260?????? Files specific to Freescale MPC8260 CPUs

? - mpc85xx Files specific to Freescale MPC85xx CPUs

? - nios? Files specific to Altera NIOS CPUs

? - nios2?????? Files specific to Altera Nios-II CPUs

? - ppc4xx?? Files specific to AMCC PowerPC 4xx CPUs

? - pxa???????? Files specific to Intel XScale PXA CPUs

? - s3c44b0 Files specific to Samsung S3C44B0 CPUs

? - sa1100??? Files specific to Intel StrongARM SA1100 CPUs

- disk??????????? Code for disk drive partition handling

????????? 磁盘驱动，及分区操作的代码

- doc???????????? ? Documentation (don't expect too much)

????????? 文档（不要期待太多（搞不懂为什么了 ? ））

- drivers Commonly used device drivers

????????? 通用设备驱动

- dtt??????? ? Digital Thermometer and Thermostat drivers

??????? ?? 数字温度器及调温装置驱动

- examples???? Example code for standalone applications,etc.

????????? ?? 独立应用程序的例子

- include ? Header Files

?????? ????? 头文件

- lib_arm?????? ? Files generic to ARM????? architecture

??????? ????ARM 体系结构通用的文件

- lib_avr32??? Files generic to AVR32?????? architecture

- lib_generic? Files generic to all architectures

????????? ???? 所有体系结构通用的文件

- lib_i386????? Files generic to i386???? architecture

- lib_m68k??? Files generic to m68k?? architecture

- lib_mips????? Files generic to MIPS? architecture

- lib_nios?????? Files generic to NIOS? architecture

- lib_ppc?????? Files generic to PowerPC architecture

- lib_sparc???? Files generic to SPARC????? architecture

- libfdt??? Library files to support flattened device trees

??????? ?? 支持平板设备树的库文件

- net????????????? Networking code

??? ????? 网络代码

- post??????????? Power On Self Test

? ???????? 上电自检

- rtc??????? Real Time Clock drivers

????? ???? 实时时钟驱动

- tools?????????? Tools to build S-Record or U-Boot images,etc.

???? ????? 编译 S-Record 和 U-Boot 镜像的工具

- api

????????? 1.3 版本的 UBOOT 还增加了一个 API 的文件夹，

????????? 这里放的是一些扩展应用的独立的 API 函数

?????????

Software Configuration:

软件配置：

=======================

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Configuration is usually done using C preprocessor defines; the

rationale behind that is to avoid dead code whenever possible.

配置是通过 C 预处理程序完成。

?

There are two classes of configuration variables:

有两类配置变量：

?

* Configuration _OPTIONS_:

? 配置选项：

? These are selectable by the user and have names beginning with

? "CONFIG_".

? 是可由用户选择并以“ CONFIG_ ”开头

?

* Configuration _SETTINGS_:

? 配置设置

? These depend on the hardware etc. and should not be meddled with if

? you don't know what you're doing; they have names beginning with

? "CFG_".

? 依赖于硬件，由“ CFG_ ”开头

?

Later we will add a configuration tool - probably similar to or even

identical to what's used for the Linux kernel. Right now,we have to

do the configuration by hand,which means creating some symbolic

links and editing some configuration files. We use the TQM8xxL boards

as an example here.

以后我们将加入类似 Linux 内核一样的配置工具。但现在只能手工配置。

我们将以 TQM8XXL 为例。

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第一步：

Selection of Processor Architecture and Board Type:

选择处理器架构和板类型：

---------------------------------------------------

?

For all supported boards there are ready-to-use default

configurations available; just type "make <board_name>_config".

对所有已至此的板都已经有可用的默认配置，只要执行：

make <boare_name>_config

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下面是例子

Example: For a TQM823L module type:

?

?????? cd u-boot

?????? make TQM823L_config

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For the Cogent platform,you need to specify the CPU type as well;

e.g. "make cogent_mpc8xx_config". And also configure the cogent

directory according to the instructions in cogent/README.

对于加强型平台还要指定 CPU 类型，请阅读 cogent/READM

?

?

第二步

Configuration Options:

配置选项：

----------------------

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Configuration depends on the combination of board and CPU type; all

such information is kept in a configuration file

配置依赖于板和 CPU ，所有配置设置信息保存在：

"include/configs/<board_name>.h ".

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Example: For a TQM823L module,all configuration settings are in

"include/configs/TQM823L.h".

?

?

Many of the options are named exactly as the corresponding Linux

kernel configuration options. The intention is to make it easier to

build a config tool - later.

?

?

The following options need to be configured:

以下的选项需要被配置：

这里 MPC 的配置比较多，如果是 SMDK2410 的话配置会少很多

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- CPU Type:? Define exactly one,e.g. CONFIG_MPC85XX.

CPU 类型 ：正确地定义一个种类，比如： CONFIG_MPC85XX

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- Board Type:?????? Define exactly one,e.g. CONFIG_MPC8540ADS.

板类型： 比如： CONFIG_MPC8540ADS

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- CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)

????????????? Define exactly one,e.g. CONFIG_ATSTK1002

CPU 子类

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- CPU Module Type: (if CONFIG_COGENT is defined)

????????????? Define exactly one of

????????????? CONFIG_CMA286_60_OLD

CPU 模型

--- FIXME --- not tested yet:

????????????? CONFIG_CMA286_60,CONFIG_CMA286_21,CONFIG_CMA286_60P,

????????????? CONFIG_CMA287_23,CONFIG_CMA287_50

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- Motherboard Type: (if CONFIG_COGENT is defined)

????????????? Define exactly one of

????????????? CONFIG_CMA101,CONFIG_CMA102

主板

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- Motherboard I/O Modules: (if CONFIG_COGENT is defined)

????????????? Define one or more of

????????????? CONFIG_CMA302

主板 I/O 模式

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- Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)

????????????? Define one or more of

????????????? CONFIG_LCD_HEARTBEAT - update a character position on

?????????????????????????????????? ? the LCD display every second with

?????????????????????????????????? ? a "rotator" |/-/|/-/

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- Board flavour: (if CONFIG_MPC8260ADS is defined)

????????????? CONFIG_ADSTYPE

????????????? Possible values are:

???????????????????? CFG_8260ADS?? - original MPC8260ADS

???????????????????? CFG_8266ADS?? - MPC8266ADS

???????????????????? CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR

???????????????????? CFG_8272ADS?? - MPC8272ADS

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- MPC824X Family Member (if CONFIG_MPC824X is defined)

????????????? Define exactly one of

????????????? CONFIG_MPC8240,CONFIG_MPC8245

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- 8xx CPU Options: (if using an MPC8xx CPU)

????????????? CONFIG_8xx_GCLK_FREQ? - deprecated: CPU clock if

?????????????????????????????????? ? get_gclk_freq() cannot work

?????????????????????????????????? ? e.g. if there is no 32KHz

?????????????????????????????????? ? reference PIT/RTC clock

????????????? CONFIG_8xx_OSCLK??? - PLL input clock (either EXTCLK

?????????????????????????????????? ? or XTAL/EXTAL)

?

- 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):

????????????? CFG_8xx_CPUCLK_MIN

????????????? CFG_8xx_CPUCLK_MAX

????????????? CONFIG_8xx_CPUCLK_DEFAULT

???????????????????? See doc/README.MPC866

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????????????? CFG_MEASURE_CPUCLK

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????????????? Define this to measure the actual CPU clock instead

????????????? of relying on the correctness of the configured

????????????? values. Mostly useful for board bringup to make sure

????????????? the PLL is locked at the intended frequency. Note

????????????? that this requires a (stable) reference clock (32 kHz

????????????? RTC clock or CFG_8XX_XIN)

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- Intel Monahans options:

????????????? CFG_MONAHANS_RUN_MODE_OSC_RATIO

?

????????????? Defines the Monahans run mode to oscillator

????????????? ratio. Valid values are 8,16,24,31. The core

????????????? frequency is this value multiplied by 13 MHz.

?

????????????? CFG_MONAHANS_TURBO_RUN_MODE_RATIO

?

????????????? Defines the Monahans turbo mode to oscillator

????????????? ratio. Valid values are 1 (default if undefined) and

????????????? 2. The core frequency as calculated above is multiplied

????????????? by this value.

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-???????? Linux Kernel Interface:

-???????? Linux 内核接口

????????????? CONFIG_CLOCKS_IN_MHZ

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????????????? U-Boot stores all clock information in Hz

????????????? internally.

?????? UBOOT 以 Hz 位单位存储时钟信息

For binary compatibility with older Linux

????????????? kernels (which expect the clocks passed in the

????????????? bd_info data to be in MHz

Linux 内核期望时钟是以 MHz 位单位传到 bd_info 的 )

the environment variable

为了和内核兼容可以定义环境变量

????????????? "clocks_in_mhz " can be defined so that U-Boot

????????????? converts clock data to MHZ before passing it to the

????????????? Linux kernel.

?????? 把 UBOOT 的时钟数据转换位 MHz 后传入内核

????????????? When CONFIG_CLOCKS_IN_MHZ is defined,a definition of

????????????? "clocks_in_mhz=1" is automatically included in the

????????????? default environment.

? ????? 当 CONFIG_CLOCKS_IN_MHZ 被定义后 clocks_in_mhz=1

会被自动包含到环境中

?

????????????? CONFIG_MEMSIZE_IN_BYTES ???????? [relevant for MIPS only]

?????? 只跟 MIPS 相关

?

????????????? When transferring memsize parameter to linux,some versions

????????????? expect it to be in bytes,others in MB.

????????????? Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.

?????? 对于内存大小的参数可以定义 CONFIG_MEMSIZE_IN_BYTES

?????? 以 BYTES 位单位

?

????????????? CONFIG_OF_LIBFDT

?

????????????? New kernel versions are expecting firmware settings to be

????????????? passed using flattened device trees (based on open firmware

????????????? concepts).

?

????????????? CONFIG_OF_LIBFDT

????????????? ?* New libfdt-based support

????????????? ?* Adds the "fdt" command

????????????? ?* The bootm command automatically updates the fdt

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????????????? OF_CPU - The proper name of the cpus node.

????????????? OF_SOC - The proper name of the soc node.

????????????? OF_TBCLK - The timebase frequency.

????????????? OF_STDOUT_PATH - The path to the console device

?

????????????? boards with QUICC Engines require OF_QE to set UCC MAC

????????????? addresses

?

????????????? CONFIG_OF_BOARD_SETUP

?

????????????? Board code has addition modification that it wants to make

????????????? to the flat device tree before handing it off to the kernel

?

????????????? CONFIG_OF_BOOT_CPU

?

????????????? This define fills in the correct boot CPU in the boot

????????????? param header,the default value is zero if undefined.

?

-???????? Serial Ports:

-???????? 串口

????????????? CFG_PL010_SERIAL

?

????????????? Define this if you want support for Amba PrimeCell PL010 UARTs.

????? ? 要支持 Amba PrimeCell PL010 UARTs 就定义此项

?

????????????? CFG_PL011_SERIAL

?

????????????? Define this if you want support for Amba PrimeCell PL011 UARTs.

?

????????????? CONFIG_PL011_CLOCK

?

????????????? If you have Amba PrimeCell PL011 UARTs,set this variable to

????????????? the clock speed of the UARTs.

?

????????????? CONFIG_PL01x_PORTS

?

????????????? If you have Amba PrimeCell PL010 or PL011 UARTs on your board,

????????????? define this to a list of base addresses for each (supported)

????????????? port. See e.g. include/configs/versatile.h

?

?

-???????? Console Interface:

-???????? 控制台接口

????????????? Depending on board,define exactly one serial port

?????? ?????? (like CONFIG_8xx_CONS_SMC1,CONFIG_8xx_CONS_SMC2,

????????????? CONFIG_8xx_CONS_SCC1,...),or switch off the serial

????????????? console by defining CONFIG_8xx_CONS_NONE

?????? 依赖于板，定义一个串口

?

????????????? Note: if CONFIG_8xx_CONS_NONE is defined,the serial

????????????? port routines must be defined elsewhere

????????????? (i.e. serial_init(),serial_getc(),...)

?

????????????? CONFIG_CFB_CONSOLE

????????????? Enables console device for a color framebuffer.

使能控制台器件的彩色帧缓存

Needs following

????????????? defines (cf. smiLynxEM,i8042,board/eltec/bab7xx)

???????????????????? VIDEO_FB_LITTLE_ENDIAN????? graphic memory organisation

????????????????????????????????????????? (default big endian)

???????????????????? VIDEO_HW_RECTFILL? graphic chip supports

????????????????????????????????????????? rectangle fill

????????????????????????????????????????? (cf. smiLynxEM)

???????????????????? VIDEO_HW_BITBLT????????????? graphic chip supports

????????????????????????????????????????? bit-blit (cf. smiLynxEM)

???????????????????? VIDEO_VISIBLE_COLS visible pixel columns

????????????????????????????????????????? (cols=pitch)

???????????????????? VIDEO_VISIBLE_ROWS?????? visible pixel rows

???????????????????? VIDEO_PIXEL_SIZE?????? bytes per pixel

???????????????????? VIDEO_DATA_FORMAT graphic data format

????????????????????????????????????????? (0-5,cf. cfb_console.c)

???????????????????? VIDEO_FB_ADRS?????????? framebuffer address

???????????????????? VIDEO_KBD_INIT_FCT keyboard int fct

????????????????????????????????????????? (i.e. i8042_kbd_init())

???????????????????? VIDEO_TSTC_FCT???????? test char fct

????????????????????????????????????????? (i.e. i8042_tstc)

???????????????????? VIDEO_GETC_FCT???????? get char fct

????????????????????????????????????????? (i.e. i8042_getc)

???????????????????? CONFIG_CONSOLE_CURSOR?? cursor drawing on/off

????????????????????????????????????????? (requires blink timer

????????????????????????????????????????? cf. i8042.c)

???????????????????? CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)

???????????????????? CONFIG_CONSOLE_TIME? display time/date info in

????????????????????????????????????????? upper right corner

????????????????????????????????????????? (requires CONFIG_CMD_DATE)

???????????????????? CONFIG_VIDEO_LOGO?????? display Linux logo in

????????????????????????????????????????? upper left corner

???????????????????? CONFIG_VIDEO_BMP_LOGO??? use bmp_logo.h instead of

????????????????????????????????????????? linux_logo.h for logo.

????????????????????????????????????????? Requires CONFIG_VIDEO_LOGO

???????????????????? CONFIG_CONSOLE_EXTRA_INFO

????????????????????????????????????????? additional board info beside

????????????????????????????????????????? the logo

?

????????????? When CONFIG_CFB_CONSOLE is defined,video console is

????????????? default i/o.

当定义了 CONFIG_CFB_CONSOLE 后，视频控制台位默认 I/O

Serial console can be forced with

????????????? environment 'console=serial'.

?

????????????? When CONFIG_SILENT_CONSOLE is defined,all console

????????????? messages (by U-Boot and Linux!) can be silenced with

????????????? the "silent" environment variable.

? 若定义了 CONFIG_SILENT_CONSOLE ，则所有控制台信息

都为缄默模式

See

????????????? doc/README.silent for more information.

查看 doc/README.silent 获得帮助

?

-???????? Console Baudrate:

-???????? 控制台波特率

????????????? CONFIG_BAUDRATE - in bps

????????????? Select one of the baudrates listed in

????????????? CFG_BAUDRATE_TABLE,see below.

????????????? CFG_BRGCLK_PRESCALE,baudrate prescale

?

-???????? Interrupt driven serial port input:

-???????? 中断驱动串口输入

????????????? CONFIG_SERIAL_SOFTWARE_FIFO

?

????????????? PPC405GP only.

?????? 仅对 PPC405GP

????????????? Use an interrupt handler for receiving data on the

????????????? serial port. It also enables using hardware handshake

????????????? (RTS/CTS) and UART's built-in FIFO. Set the number of

????????????? bytes the interrupt driven input buffer should have.

?

????????????? Leave undefined to disable this feature,including

????????????? disable the buffer and hardware handshake.

?

-???????? Console UART Number:

-???????? 控制台 UART 数

????????????? CONFIG_UART1_CONSOLE

?

????????????? AMCC PPC4xx only.

?? ???? 仅对 AMCC PPC4XX

????????????? If defined internal UART1 (and not UART0) is used

????????????? as default U-Boot console.

?

-???????? Boot Delay:???

-???????? 启动延时

-???????? ????CONFIG_BOOTDELAY - in seconds

????????????? Delay before automatically booting the default image;

?????? 自动引导默认镜像的延时

????????????? set to -1 to disable autoboot.

?????? -1 为禁止自动启动

?

????????????? See doc/README.autoboot for these options that

????????????? work with CONFIG_BOOTDELAY. None are required.

?????? 关于 CONFIG_BOOTDELAY 的选项请查阅 doc/README.autoboot

引导重试环境变量

????????????? CONFIG_BOOT_RETRY_TIME

????????????? CONFIG_BOOT_RETRY_MIN

这两个决定在 UBOOT 停止引导等待命令过程中的行为，

若环境变量 "bootretry" 存在，则 "bootretry" 的值将被应用，否则默认超时时间为

CONFIG_BOOT_RETRY_TIME 的值， CONFIG_BOOT_RETRY_MIN 被选为 CONFIG_BOOT_RETRY_TIME 的缺省值，若 CONFIG_BOOT_RETRY_TIME 为负则不会发生超时。

?

????????????? CONFIG_AUTOBOOT_KEYED

????????????? CONFIG_AUTOBOOT_PROMPT

????????????? CONFIG_AUTOBOOT_DELAY_STR

????????????? CONFIG_AUTOBOOT_STOP_STR

????????????? CONFIG_AUTOBOOT_DELAY_STR2

????????????? CONFIG_AUTOBOOT_STOP_STR2

? "bootdelaykey"? environment variable

? "bootstopkey"?? ? environment variable

? "bootdelaykey2" environment variable

? "bootstopkey2"? environment variable

这些选项给停止自动引导提供更多的控制。当应用他们时就需要输入特定的字符或字符串来停止或延时自动引导。

CONFIG_AUTOBOOT_PROMPT 显示一些信，但 CONFIG_BOOTDELAY 必须被定义。

????????????? #define CONFIG_AUTOBOOT_PROMPT /

???????????????????? "autoboot in %d seconds/n",bootdelay

若 CONFIG_AUTOBOOT_DELAY_STR 或 "bootdelaykey" 被定义，但从控制台输入特定字符时，就会出现 UBOOT 提示符，停止自动引导。超时后自动重新引导。

若 CONFIG_AUTOBOOT_STOP_STR 或 "bootstopkey" 被定义，但从控制台输入特定字符时，就会出现 UBOOT 提示符，停止自动引导。超时后不自动重新引导。

CONFIG_AUTOBOOT_DELAY_STR2 或 "bootstopkey2" 则允许你有两个进入字符

????????????? CONFIG_ZERO_BOOTDELAY_CHECK

????????????? CONFIG_RESET_TO_RETRY

CONFIG_ZERO_BOOTDELAY_CHECK 此选项能让你通过敲击一个键来停止自动引导。

CONFIG_RESET_TO_RETRY 当 CONFIG_BOOT_RETRY_TIME 被定义时才有效。当超时时板将重启。

?

?

-???????? Autoboot Command:

-???????? 自动引导命令

????????????? CONFIG_BOOTCOMMAND

????????????? Only needed when CONFIG_BOOTDELAY is enabled;

?????? 当 CONFIG_BOOTDELAY 使能使需要

????????????? define a command string that is automatically executed

????????????? when no character is read on the console interface

????????????? within "Boot Delay" after reset.

????? ? 当启动延时时间内没有从控制接口都取字符时自动执行

它定义的命令字符

?

????????????? CONFIG_BOOTARGS

????????????? This can be used to pass arguments to the bootm

????????????? command. The value of CONFIG_BOOTARGS goes into the

????????????? environment value "bootargs".

????? ? 传递参数到 bootm 命令

?

????????????? CONFIG_RAMBOOT and CONFIG_NFSBOOT

????????????? The value of these goes into the environment as

????????????? "ramboot" and "nfsboot" respectively,and can be used

????????????? as a convenience,when switching between booting from

????????????? RAM and NFS.

?????? 实现从 RAM 和 NFS 启动的转换

?

- Pre-Boot Commands:

????????????? CONFIG_PREBOOT

?

????????????? When this option is #defined,the existence of the

????????????? environment variable "preboot" will be checked

????????????? immediately before starting the CONFIG_BOOTDELAY

????????????? countdown and/or running the auto-boot command resp.

????????????? entering interactive mode.

?

????????????? This feature is especially useful when "preboot" is

????????????? automatically generated or modified. For an example

????????????? see the LWMON board specific code: here "preboot" is

????????????? modified when the user holds down a certain

????????????? combination of keys on the (special) keyboard when

????????????? booting the systems

?

-???????? Serial Download Echo Mode:

-???????? 串口下载回显模式

????????????? CONFIG_LOADS_ECHO

????????????? If defined to 1,all characters received during a

????????????? serial download (using the "loads" command) are

????????????? echoed back.

当设置为 1 时串口在下载时所有接受的字符都回显出来

This might be needed by some terminal

????????????? emulations (like "cu"),but may as well just take

????????????? time on others. This setting #define's the initial

????????????? value of the "loads_echo" environment variable.

?????? 这个设置定义了 "loads_echo" 的环境变量

?

-???????? Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined )

-???????? Kgdb 串口波特率

????????????? CONFIG_KGDB_BAUDRATE

????????????? Select one of the baudrates listed in

????????????? CFG_BAUDRATE_TABLE,

?????? 这里定义了所有可用波特率的表

see below.

?

-???????? Monitor Functions:

-???????? 监视函数

????????????? Monitor commands can be included or excluded

????????????? from the build by using the #include files

????????????? 通过编译时包含 "config_cmd_all.h" 头文件来包含所有的监控命令

And 通过 #undef'ing 去掉不需要的命令 unwanted

????????????? commands,or using "config_cmd_default.h" 为包含默认命令

????????????? and augmenting with additional #define's

????????????? for wanted commands.

?

????????????? The default command configuration includes all commands

????????????? except those marked below with a "*".

?????? 默认命令配置包含所有不带“ * ”标记的命令

?

????????????? CONFIG_CMD_ASKENV???? * ask for env variable

???????????????????????????????? 请求环境变量

????????????? CONFIG_CMD_AUTOSCRIPT??? ? Autoscript Support

????????????????????????????????? 自动脚本支持

????????????? CONFIG_CMD_BDI??????? ????bdinfo

????????????? CONFIG_CMD_BEDBUG????? * Include BedBug Debugger

????????????? CONFIG_CMD_BMP???????????? * BMP support

????????????? CONFIG_CMD_BSP????????????? * Board specific commands

????????????? CONFIG_CMD_BOOTD ? ???bootd

????????????? CONFIG_CMD_CACHE ????? * icache,dcache

????????????? CONFIG_CMD_CONSOLE?? ? coninfo

????????????? CONFIG_CMD_DATE??????????? * support for RTC,date/time...

????????????? CONFIG_CMD_DHCP?????????? * DHCP support

????????????? CONFIG_CMD_DIAG??????????? * Diagnostics

????????????? CONFIG_CMD_DOC???????????? * Disk-On-Chip Support

????????????? CONFIG_CMD_DTT????????????? * Digital Therm and Thermostat

????????????? CONFIG_CMD_ECHO????????? ? echo arguments

????????????? CONFIG_CMD_EEPROM???? * EEPROM read/write support

????????????? CONFIG_CMD_ELF????????????? * bootelf,bootvx

????????????? CONFIG_CMD_ENV???????????? ? saveenv

????????????? CONFIG_CMD_FDC???????????? * Floppy Disk Support

????????????? CONFIG_CMD_FAT??????? ?? * FAT partition support

????????????? CONFIG_CMD_FDOS?????????? * Dos diskette Support

????????????? CONFIG_CMD_FLASH? ??flinfo,erase,protect

????????????? CONFIG_CMD_FPGA?????????? ? FPGA device initialization support

????????????? CONFIG_CMD_HWFLOW?? * RTS/CTS hw flow control

????????????? CONFIG_CMD_I2C??????? ? * I2C serial bus support

????????????? CONFIG_CMD_IDE??????? ? * IDE harddisk support

????????????? CONFIG_CMD_IMI??????? ? iminfo

????????????? CONFIG_CMD_IMLS??????????? ? List all found images

????????????? CONFIG_CMD_IMMAP? ??? * IMMR dump support

????????????? CONFIG_CMD_IRQ????????????? ??? * irqinfo

????????????? CONFIG_CMD_ITEST??? ???Integer/string test of 2 values

????????????? CONFIG_CMD_JFFS2??? ??? * JFFS2 Support

????????????? CONFIG_CMD_KGDB????????? * kgdb

????????????? CONFIG_CMD_LOADB ? ??loadb

????????????? CONFIG_CMD_LOADS ? ??loads

????????????? CONFIG_CMD_MEMORY??? ? md,mm,nm,mw,cp,cmp,crc,base,

?????????????????????????????????? ? loop,loopw,mtest

????????????? CONFIG_CMD_MISC?????????? ? Misc functions like sleep etc

????????????? CONFIG_CMD_MMC?????????? * MMC memory mapped support

????????????? CONFIG_CMD_MII??????? ?? * MII utility commands

????????????? CONFIG_CMD_NAND????????? * NAND support

????????????? CONFIG_CMD_NET????????????? ? bootp,tftpboot,rarpboot

????????????? CONFIG_CMD_PCI??????? * pciinfo

????????????? CONFIG_CMD_PCMCIA???????????? * PCMCIA support

????????????? CONFIG_CMD_PING??????????? * send ICMP ECHO_REQUEST to network

?????????????????????????????????? ? host

????????????? CONFIG_CMD_PORTIO?????? * Port I/O

????????????? CONFIG_CMD_REGINFO??? * Register dump

????????????? CONFIG_CMD_RUN???????????? ? run command in env variable

????????????? CONFIG_CMD_SAVES? * save S record dump

????????????? CONFIG_CMD_SCSI???????????? * SCSI Support

????????????? CONFIG_CMD_SDRAM?????? * print SDRAM configuration information

?????????????????????????????????? ? (requires CONFIG_CMD_I2C)

????????????? CONFIG_CMD_SETGETDCR????? ? Support for DCR Register access

?????????????????????????????????? ? (4xx only)

????????????? CONFIG_CMD_SPI??????? ??? * SPI serial bus support

?????? ?????? CONFIG_CMD_USB????????????? * USB support

????????????? CONFIG_CMD_VFD???????????? * VFD support (TRAB)

????????????? CONFIG_CMD_CDP???????????? * Cisco Discover Protocol support

????????????? CONFIG_CMD_FSL????????????? ??? * Microblaze FSL support

?

?

????????????? EXAMPLE: If you want all functions except of network

????????????? support you can write:

???? ?? 比如你需要除网络外的所有函数，你可以写入下面几行

?

????????????? #include "config_cmd_all.h"

????????????? #undef CONFIG_CMD_NET

?

?????? Other Commands:

????????????? fdt (flattened device tree) command: CONFIG_OF_LIBFDT

?

?????? Note:????? Don't enable the "icache" and "dcache" commands

????????????? (configuration option CONFIG_CMD_CACHE) unless you know

????????????? what you (and your U-Boot users) are doing. Data

????????????? cache cannot be enabled on systems like the 8xx or

????????????? 8260 (where accesses to the IMMR region must be

????????????? uncached),and it cannot be disabled on all other

????????????? systems where we (mis-) use the data cache to hold an

????????????? initial stack and some data.

?

?

????????????? XXX - this list needs to get updated!

?

-???????? Watchdog:

-???????? 看门狗

????????????? CONFIG_WATCHDOG

????????????? If this variable is defined,it enables watchdog

????????????? support.

若被定义则支持看门狗

There must be support in the platform specific

????????????? code for a watchdog. For the 8xx and 8260 CPUs,the

????????????? SIU Watchdog feature is enabled in the SYPCR

????????????? register.

?

-???????? U-Boot Version:

-???????? UBOOT 版本

????????????? CONFIG_VERSION_VARIABLE

????????????? If this variable is defined,an environment variable

????????????? named "ver" is created by U-Boot showing the U-Boot

????????????? version as printed by the "version" command.

????????????? This variable is readonly.

?????? 若这个变量被定义则 "ver" 的环境变量被 UBOOT 创建，通过 "version" 命令进行读取，此变量为只读

?

-???????? Real-Time Clock:

-???????? 实时时钟

?

????????????? When CONFIG_CMD_DATE is selected,the type of the RTC

????????????? has to be selected,too. Define exactly one of the

????????????? following options:

?????? 当 CONFIG_CMD_DATE 被选取时， RTC 的类型也要被选取，从以下选项中选一个最接近的

?

????????????? CONFIG_RTC_MPC8xx? - use internal RTC of MPC8xx

????????????? CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC

????????????? CONFIG_RTC_MC13783?????? - use MC13783 RTC

????????????? CONFIG_RTC_MC146818???? - use MC146818 RTC

????????????? CONFIG_RTC_DS1307?? - use Maxim,Inc. DS1307 RTC

????????????? CONFIG_RTC_DS1337?? - use Maxim,Inc. DS1337 RTC

????????????? CONFIG_RTC_DS1338?? - use Maxim,Inc. DS1338 RTC

????????????? CONFIG_RTC_DS164x?? - use Dallas DS164x RTC

????????????? CONFIG_RTC_ISL1208? - use Intersil ISL1208 RTC

????????????? CONFIG_RTC_MAX6900????? - use Maxim,Inc. MAX6900 RTC

????????????? CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337

?

????????????? Note that if the RTC uses I2C,then the I2C interface

????????????? must also be configured. See I2C Support,below.

?????? 若 RTC 用 I2C ，则 I2C 接口也要被配置。

?

-???????? Timestamp Support:

-???????? 时间戳支持

?

????????????? When CONFIG_TIMESTAMP is selected,the timestamp

????????????? (date and time) of an image is printed by image

????????????? commands like bootm or iminfo. This option is

????????????? automatically enabled when you select CONFIG_CMD_DATE .

?????? 当选择了 CONFIG_CMD_DATE 后这个选项被自动使能，通过映像命令来打印映像的时间戳

?

-???????? Partition Support:

-???????? 分区支持

????????????? CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION

????????????? and/or CONFIG_ISO_PARTITION

?

????????????? If IDE or SCSI support is enabled (CONFIG_CMD_IDE or

????????????? CONFIG_CMD_SCSI ) you must configure support for at

????????????? least one partition type as well.

?

-???????? IDE Reset method:

-???????? 对 IDE 的支持

????????????? CONFIG_IDE_RESET_ROUTINE - this is defined in several

????????????? board configurations files but used nowhere!

?

????????????? CONFIG_IDE_RESET - is this is defined,IDE Reset will

????????????? be performed by calling the function

???????????????????? ide_set_reset(int reset)

????????????? which has to be defined in a board specific file

?

- ATAPI Support:

????????????? CONFIG_ATAPI

?

????????????? Set this to enable ATAPI support.

?

- LBA48 Support

????????????? CONFIG_LBA48

?

????????????? Set this to enable support for disks larger than 137GB

????????????? Also look at CFG_64BIT_LBA,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL

????????????? Whithout these,LBA48 support uses 32bit variables and will 'only'

????????????? support disks up to 2.1TB.

?

????????????? CFG_64BIT_LBA:

???????????????????? When enabled,makes the IDE subsystem use 64bit sector addresses.

???????????????????? Default is 32bit.

?

- SCSI Support:

????????????? At the moment only there is only support for the

????????????? SYM53C8XX SCSI controller; define

????????????? CONFIG_SCSI_SYM53C8XX to enable it.

?

????????????? CFG_SCSI_MAX_LUN [8],CFG_SCSI_MAX_SCSI_ID [7] and

????????????? CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *

????????????? CFG_SCSI_MAX_LUN] can be adjusted to define the

????????????? maximum numbers of LUNs,SCSI ID's and target

????????????? devices.

????????????? CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)

?

-???????? NETWORK Support (PCI):

-???????? 网络支持（ PCI ）

????????????? CONFIG_E1000

????????????? Support for Intel 8254x gigabit chips.

?

????????????? CONFIG_E1000_FALLBACK_MAC

????????????? default MAC for empty EEPROM after production.

?

????????????? CONFIG_EEPRO100

????????????? Support for Intel 82557/82559/82559ER chips.

????????????? Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM

????????????? write routine for first time initialisation.

?

????????????? CONFIG_TULIP

????????????? Support for Digital 2114x chips.

????????????? Optional CONFIG_TULIP_SELECT_MEDIA for board specific

????????????? modem chip initialisation (KS8761/QS6611).

?

????????????? CONFIG_NATSEMI

????????????? Support for National dp83815 chips.

?

????????????? CONFIG_NS8382X

????????????? Support for National dp8382[01] gigabit chips.

?

- NETWORK Support (other):

?

????????????? CONFIG_DRIVER_LAN91C96

????????????? Support for SMSC's LAN91C96 chips.

?

???????????????????? CONFIG_LAN91C96_BASE

???????????????????? Define this to hold the physical address

???????????????????? of the LAN91C96's I/O space

?

???????????????????? CONFIG_LAN91C96_USE_32_BIT

???????????????????? Define this to enable 32 bit addressing

?

????????????? CONFIG_DRIVER_SMC91111

????????????? Support for SMSC's LAN91C111 chip

?

???????????????????? CONFIG_SMC91111_BASE

???????????????????? Define this to hold the physical address

???????????????????? of the device (I/O space)

?

???????????????????? CONFIG_SMC_USE_32_BIT

???????????????????? Define this if data bus is 32 bits

?

???????????????????? CONFIG_SMC_USE_IOFUNCS

???????????????????? Define this to use i/o functions instead of macros

???????????????????? (some hardware wont work with macros)

?

????????????? CONFIG_DRIVER_SMC911X

????????????? Support for SMSC's LAN911x and LAN921x chips

?

???????????????????? CONFIG_DRIVER_SMC911X_BASE

???????????????????? Define this to hold the physical address

???????????????????? of the device (I/O space)

?

???????????????????? CONFIG_DRIVER_SMC911X_32_BIT

???????????????????? Define this if data bus is 32 bits

?

???????????????????? CONFIG_DRIVER_SMC911X_16_BIT

???????????????????? Define this if data bus is 16 bits. If your processor

???????????????????? automatically converts one 32 bit word to two 16 bit

???????????????????? words you may also try CONFIG_DRIVER_SMC911X_32_BIT.

?

-???????? USB Support:

-???????? USB 支持

????????????? At the moment only the UHCI host controller is

????????????? supported (PIP405,MIP405,MPC5200);

目前只支持通用主控制器接口的主控制器

defineCONFIG_USB_UHCI to enable it.

定义 CONFIG_USB_UHCI 允许 USB 主控制器

????????????? define CONFIG_USB_KEYBOARD to enable the USB Keyboard

定义 CONFIG_USB_KEYBOARD 允许 USB 键盘

????????????? and define CONFIG_USB_STORAGE to enable the USB

?????? 定义 CONFIG_USB_STORAGE 来允许 USB 储存器

????????????? storage devices.

????????????? Note:

????????????? Supported are USB Keyboards and USB Floppy drives

????????????? (TEAC FD-05PUB).

????????????? MPC5200 USB requires additional defines:

???????????????????? CONFIG_USB_CLOCK

????????????? ????????????? for 528 MHz Clock: 0x0001bbbb

???????????????????? CONFIG_USB_CONFIG

??????????????????????????? for differential drivers: 0x00001000

??????????????????????????? for single ended drivers: 0x00005000

???????????????????? CFG_USB_EVENT_POLL

??????????????????????????? May be defined to allow interrupt polling

??????????????????????????? instead of using asynchronous interrupts

?

-???????? USB Device:

-???????? USB 器件

????????????? Define the below if you wish to use the USB console.

????? ? 若想使用 USB 控制台，定义下面的变量

????????????? Once firmware is rebuilt from a serial console issue the

????????????? command "setenv stdin usbtty; setenv stdout usbtty" and

????????????? attach your USB cable. The Unix command "dmesg" should print

????????????? it has found a new device. The environment variable usbtty

????????????? can be set to gserial or cdc_acm to enable your device to

????????????? appear to a USB host as a Linux gserial device or a

????????????? Common Device Class Abstract Control Model serial device.

????????????? If you select usbtty = gserial you should be able to enumerate

????????????? a Linux host by

????????????? # modprobe usbserial vendor=0xVendorID product=0xProductID

????????????? else if using cdc_acm,simply setting the environment

????????????? variable usbtty to be cdc_acm should suffice. The following

????????????? might be defined in YourBoardName.h

?

???????????????????? CONFIG_USB_DEVICE

???????????????????? Define this to build a UDC device

?????? ???? 定义这项来构建 UDC 设备

?

???????????????????? CONFIG_USB_TTY

???????????????????? Define this to have a tty type of device available to

???????????????????? talk to the UDC device

????????? 定义，以拥有一个和 UDC 通信的 tty 设备。

?

???????????????????? CFG_CONSOLE_IS_IN_ENV

???????????????????? Define this if you want stdin,stdout &/or stderr to

???????????????????? be set to usbtty.

????????? 若想 stdin,stdout,stderr 被设置到 usbtty 就定义此项

?

???????????????????? mpc8xx:

??????????????????????????? CFG_USB_EXTC_CLK 0xBLAH

??????????????????????????? Derive USB clock from external clock "blah"

??????????????????????????? - CFG_USB_EXTC_CLK 0x02

?

??????????????????????????? CFG_USB_BRG_CLK 0xBLAH

??????????????????????????? Derive USB clock from brgclk

??????????????????????????? - CFG_USB_BRG_CLK 0x04

?

????????????? If you have a USB-IF assigned VendorID then you may wish to

????????????? define your own vendor specific values either in BoardName.h

????????????? or directly in usbd_vendor_info.h . If you don't define

????????????? CONFIG_USBD_MANUFACTURER,CONFIG_USBD_PRODUCT_NAME,

????????????? CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID,then U-Boot

????????????? should pretend to be a Linux device to it's target host.

???? ? 若没有定义 CONFIG_USBD_MANUFACTURER,

????????????? CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID 则 UBOOT 就对其目标主机假装成一个 Linux 设备

?

???????????????????? CONFIG_USBD_MANUFACTURER

???????????????????? Define this string as the name of your company for

???????????????????? - CONFIG_USBD_MANUFACTURER "my company"

?

???????????????????? CONFIG_USBD_PRODUCT_NAME

???????????????????? Define this string as the name of your product

???????????????????? - CONFIG_USBD_PRODUCT_NAME "acme usb device"

?

???????????????????? CONFIG_USBD_VENDORID

???????????????????? Define this as your assigned Vendor ID from the USB

???????????????????? Implementors Forum. This *must* be a genuine Vendor ID

???????????????????? to avoid polluting the USB namespace.

???????????????????? - CONFIG_USBD_VENDORID 0xFFFF

?

???????????????????? CONFIG_USBD_PRODUCTID

???????????????????? Define this as the unique Product ID

???????????????????? for your device

???????????????????? - CONFIG_USBD_PRODUCTID 0xFFFF

?

?

-???????? MMC Support:

-???????? MMC 支持

????????????? The MMC controller on the Intel PXA is supported. To

????????????? enable this define CONFIG_MMC. The MMC can be

????????????? accessed from the boot prompt by mapping the device

????????????? to physical memory similar to flash. Command line is

????????????? enabled with CONFIG_CMD_MMC. The MMC driver also works with

????????????? the FAT fs. This is enabled with CONFIG_CMD_FAT.

?

-???????? Journaling Flash filesystem support:

-???????? Flash 日志文件系统支持

????????????? CONFIG_JFFS2_NAND,CONFIG_JFFS2_NAND_OFF,CONFIG_JFFS2_NAND_SIZE,

????????????? CONFIG_JFFS2_NAND_DEV

????????????? Define these for a default partition on a NAND device

???? ? 定义这些作为 NAND 缺省分区支持

?

????????????? CFG_JFFS2_FIRST_SECTOR,

????????????? CFG_JFFS2_FIRST_BANK,CFG_JFFS2_NUM_BANKS

????????????? Define these for a default partition on a NOR device

?????? 定义这些作为 NOR 缺省分区支持

?

????????????? CFG_JFFS_CUSTOM_PART

????????????? Define this to create an own partition. You have to provide a

????????????? function struct part_info* jffs2_part_info(int part_num)

????? ? 定义自己的分区，你必须提供函数结构

part_info* jffs2_part_info(int part_num)

?

????????????? If you define only one JFFS2 partition you may also want to

?????? 若只定义一个 JFFF2 分区则用以下命令

????????????? #define CFG_JFFS_SINGLE_PART????? 1

????????????? to disable the command chpart. This is the default when you

????????????? have not defined a custom partition

?

- Keyboard Support:

????????????? CONFIG_ISA_KEYBOARD

?

????????????? Define this to enable standard (PC-Style) keyboard

????????????? support

?

????????????? CONFIG_I8042_KBD

????????????? Standard PC keyboard driver with US (is default) and

????????????? GERMAN key layout (switch via environment 'keymap=de') support.

????????????? Export function i8042_kbd_init,i8042_tstc and i8042_getc

????????????? for cfb_console. Supports cursor blinking.

?

-???????? Video support:

-???????? 视频支持

????????????? CONFIG_VIDEO

?

????????????? Define this to enable video support (for output to

????????????? video).

?????? 定义此项允许输出视频

?

????????????? CONFIG_VIDEO_CT69000

?

????????????? Enable Chips & Technologies 69000 Video chip

?

????????????? CONFIG_VIDEO_SMI_LYNXEM

????????????? Enable Silicon Motion SMI 712/710/810 Video chip.

支持慧荣科技 SMI 712/710/810 视频芯片

The

????????????? video output is selected via environment 'videoout'

????????????? (1 = LCD and 2 = CRT). If videoout is undefined,CRT is

????????????? assumed.

?????? 视频输出通过环境变量 'videoout' 选择， 1 为 LCD ， 2 为 CRT ，默认为 CRT

?

????????????? For the CT69000 and SMI_LYNXEM drivers,videomode is

????????????? selected via environment 'videomode'. Two different ways

????????????? are possible:

????????????? - "videomode=num"?? 'num' is a standard LiLo mode numbers.

?????? 视频模式由环境变量 'videomode' 选择

?????? - "videomode=num"

????????????? Following standard modes are supported (* is default):

?

????????????? ???? ?Colors????? 640x480 800x600 1024x768 1152x864 1280x1024

????????????? -------------+---------------------------------------------

????????????? ????? 8 bits |????? 0x301*? 0x303??? 0x305? ? 0x161?????? ??? 0x307

????????????? ???? 15 bits |????? 0x310??? 0x313??? 0x316? ? 0x162?????? ??? 0x319

????????????? ???? 16 bits |????? 0x311???? 0x314??? 0x317? ? 0x163?????? ??? 0x31A

????????????? ???? 24 bits |????? 0x312??? 0x315??? 0x318? ??? ???? ??? 0x31B

????????????? -------------+---------------------------------------------

?????? 应用举例

????????????? (i.e. setenv videomode 317; saveenv; reset;)

?

????????????? - "videomode=bootargs" all the video parameters are parsed

????????????? from the bootargs. (See drivers/video/videomodes.c )

?

?

????????????? CONFIG_VIDEO_SED13806

????????????? Enable Epson SED13806 driver. This driver supports 8bpp

????????????? and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP

????????????? or CONFIG_VIDEO_SED13806_16BPP

?

- Keyboard Support:

????????????? CONFIG_KEYBOARD

?

????????????? Define this to enable a custom keyboard support.

????????????? This simply calls drv_keyboard_init() which must be

????????????? defined in your board-specific files.

????????????? The only board using this so far is RBC823.

?

-???????? LCD Support:??????

-???????? 支持 LCD

?????? CONFIG_LCD

?

????????????? Define this to enable LCD support (for output to LCD

????????????? display); also select one of the supported displays

????????????? by defining one of these:

?????? 定义此项来支持 LCD 输出，同时从以下几个选项中选一个来配置

?

????????????? CONFIG_ATMEL_LCD:

?

???????????????????? HITACHI TX09D70VM1CCA,3.5",240x320.

????????? 日立 TX09D70VM1CCA,240x320

?

????????????? CONFIG_NEC_NL6448AC33:

?

???????????????????? NEC NL6448AC33-18. Active,color,single scan.

?

????????????? CONFIG_NEC_NL6448BC20

?

???????????????????? NEC NL6448BC20-08. 6.5",640x480.

???????????????????? Active,single scan.

?

????????????? CONFIG_NEC_NL6448BC33_54

?

???????????????????? NEC NL6448BC33-54. 10.4",single scan.

?

????????????? CONFIG_SHARP_16x9

?

???????????????????? Sharp 320x240. Active,single scan.

???????????????????? It isn't 16x9,and I am not sure what it is.

?

????????????? CONFIG_SHARP_LQ64D341

?

???????????????????? Sharp LQ64D341 display,single scan.

?

????????????? CONFIG_HLD1045

?

???????????????????? HLD1045 display,single scan.

?

????????????? CONFIG_OPTREX_BW

?

???????????????????? Optrex?? CBL50840-2 NF-FW 99 22 M5

???????????????????? or

???????????????????? Hitachi??? LMG6912RPFC-00T

???????????????????? or

???????????????????? Hitachi??? SP14Q002

?

???????????????????? 320x240. Black & white.

?

????????????? Normally display is black on white background;

正常显示为白底黑字

Define? CFG_WHITE_ON_BLACK to get it inverted.

定义 CFG_WHITE_ON_BLACK 取得反白效果

?

-???????? Splash Screen Support:

-???????? 溅射屏幕（程序启动画面）支持

?

?????? CONFIG_SPLASH_SCREEN

?

????????????? If this option is set,the environment is checked for

????????????? a variable "splashimage". If found,the usual display

????????????? of logo,copyright and system information on the LCD

????????????? is suppressed and the BMP image at the address

????????????? specified in "splashimage" is loaded instead. The

????????????? console is redirected to the "nulldev",too. This

????????????? allows for a "silent" boot where a splash screen is

????????????? loaded very quickly after power-on.

?????? 若被设置，就会在启动时显示放于环境变量 "splashimage" 中的 BMP 图片

?

-???????? Gzip compressed BMP image support:

-???????? Gzip 压缩 BMP 图片支持

CONFIG_VIDEO_BMP_GZIP

?

????????????? If this option is set,additionally to standard BMP

????????????? images,gzipped BMP images can be displayed via the

????????????? splashscreen support or the bmp command.

?

-???????? Compression support:

-???????? 压缩支持

????????????? CONFIG_BZIP2

?

????????????? If this option is set,support for bzip2 compressed

????????????? images is included. If not,only uncompressed and gzip

????????????? compressed images are supported.

???? ?? 若被设置就能支持 bzip2 压缩格式的映像

?

????????????? NOTE: the bzip2 algorithm requires a lot of RAM,so

????????????? the malloc area (as defined by CFG_MALLOC_LEN) should

????????????? be at least 4MB.

?

-???????? MII/PHY support:

-???????? 媒体独立接口 / 物理接口收发器支持

????????????? CONFIG_PHY_ADDR

?

????????????? The address of PHY on MII bus.

?????? 媒体独立接口中物理层的地址

?

????????????? CONFIG_PHY_CLOCK_FREQ (ppc4xx)

?

????????????? The clock frequency of the MII bus

?????? 媒体独立接口时钟频率

?

????????????? CONFIG_PHY_GIGE

?

????????????? If this option is set,support for speed/duplex

????????????? detection of gigabit PHY is included.

?

????????????? CONFIG_PHY_RESET_DELAY

?

????????????? Some PHY like Intel LXT971A need extra delay after

????????????? reset before any MII register access is possible.

????????????? For such PHY,set this option to the usec delay

????????????? required. (minimum 300usec for LXT971A)

?????? 物理层接口延时，某些物理层接口如 Intel LXT971A 重启后需要一定延时时间

????????????? CONFIG_PHY_CMD_DELAY (ppc4xx)

?

????????????? Some PHY like Intel LXT971A need extra delay after

????????????? command issued before MII status register can be read

?

-???????? Ethernet address:

-???????? 以太网地址

????????????? CONFIG_ETHADDR

????????????? CONFIG_ETH2ADDR

????????????? CONFIG_ETH3ADDR

?

????????????? Define a default value for Ethernet address to use

????????????? for the respective Ethernet interface,in case this

????????????? is not determined automatically.

????? ? 配置不同以太网接口的地址

?

-???????? IP address:

-???????? IP 地址

????????????? CONFIG_IPADDR

?

????????????? Define a default value for the IP address to use for

????????????? the default Ethernet interface,in case this is not

????????????? determined through e.g. bootp.

?

-???????? Server IP address:

-???????? 服务器 IP 地址

????????????? CONFIG_SERVERIP

?

????????????? Defines a default value for the IP address of a TFTP

????????????? server to contact when using the "tftboot" command.

?????? 为 "tftboot" 命令的 TFTP 服务定义一个缺省的 IP 地址

?

-???????? Multicast TFTP Mode:

-???????? 多点传送 TFTP 模式

????????????? CONFIG_MCAST_TFTP

?

????????????? Defines whether you want to support multicast TFTP as per

????????????? rfc-2090; for example to work with atftp.? Lets lots of targets

????????????? tftp down the same boot image concurrently.? Note: the Ethernet

????????????? driver in use must provide a function: mcast() to join/leave a

????????????? multicast group.

?????? 定义是否支持多目标 tftp 同时下载同一映像，在以太网驱动中必须用 mcast() 函数来加入 / 离开多点传送。

?

????????????? CONFIG_BOOTP_RANDOM_DELAY

- BOOTP Recovery Mode:

????????????? CONFIG_BOOTP_RANDOM_DELAY

?

????????????? If you have many targets in a network that try to

????????????? boot using BOOTP,you may want to avoid that all

????????????? systems send out BOOTP requests at precisely the same

????????????? moment (which would happen for instance at recovery

????????????? from a power failure,when all systems will try to

????????????? boot,thus flooding the BOOTP server. Defining

????????????? CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be

????????????? inserted before sending out BOOTP requests.

?????? 定义一个 BOOTP 请求发送延时来避免所有系统正好同时发出 BOOTP 请求（同时发请求会导致 BOOTP 服务器溢出）

The? following delays are inserted then:

插入的延时时间表

?

????????????? 1st BOOTP request:??? delay 0 ... 1 sec

????????????? 2nd BOOTP request:?? delay 0 ... 2 sec

????????????? 3rd BOOTP request:?? delay 0 ... 4 sec

????????????? 4th and following

????????????? BOOTP requests:??????? delay 0 ... 8 sec

?

-???????? DHCP Advanced Options:

-???????? DHCP 高级选项

????????????? You can fine tune the DHCP functionality by defining

????????????? CONFIG_BOOTP_* symbols:

?

????????????? CONFIG_BOOTP_SUBNETMASK

????????????? CONFIG_BOOTP_GATEWAY

????????????? CONFIG_BOOTP_HOSTNAME

????????????? CONFIG_BOOTP_NISDOMAIN

????????????? CONFIG_BOOTP_BOOTPATH

????????????? CONFIG_BOOTP_BOOTFILESIZE

????????????? CONFIG_BOOTP_DNS

????????????? CONFIG_BOOTP_DNS2

????????????? CONFIG_BOOTP_SEND_HOSTNAME

????????????? CONFIG_BOOTP_NTPSERVER

????????????? CONFIG_BOOTP_TIMEOFFSET

????????????? CONFIG_BOOTP_VENDOREX

?

????????????? CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip

????????????? environment variable,not the BOOTP server.

?

????????????? CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS

????????????? serverip from a DHCP server,it is possible that more

????????????? than one DNS serverip is offered to the client.

????????????? If CONFIG_BOOTP_DNS2 is enabled,the secondary DNS

????????????? serverip will be stored in the additional environment

????????????? variable "dnsip2". The first DNS serverip is always

????????????? stored in the variable "dnsip",when CONFIG_BOOTP_DNS

????????????? is defined.

?

????????????? CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable

????????????? to do a dynamic update of a DNS server. To do this,they

????????????? need the hostname of the DHCP requester.

????????????? If CONFIG_BOOTP_SEND_HOSTNAME is defined,the content

????????????? of the "hostname" environment variable is passed as

????????????? option 12 to the DHCP server.

?

????????????? CONFIG_BOOTP_DHCP_REQUEST_DELAY

?

????????????? A 32bit value in microseconds for a delay between

????????????? receiving a "DHCP Offer" and sending the "DHCP Request".

????????????? This fixes a problem with certain DHCP servers that don't

????????????? respond 100% of the time to a "DHCP request". E.g. On an

????????????? AT91RM9200 processor running at 180MHz,this delay needed

????????????? to be *at least* 15,000 usec before a Windows Server 2003

????????????? DHCP server would reply 100% of the time. I recommend at

????????????? least 50,000 usec to be safe. The alternative is to hope

????????????? that one of the retries will be successful but note that

????????????? the DHCP timeout and retry process takes a longer than

????????????? this delay.

????? ? 推荐值为 50000

?

?- CDP Options:

????????????? CONFIG_CDP_DEVICE_ID

?

????????????? The device id used in CDP trigger frames.

?

????????????? CONFIG_CDP_DEVICE_ID_PREFIX

?

????????????? A two character string which is prefixed to the MAC address

????????????? of the device.

?

????????????? CONFIG_CDP_PORT_ID

?

????????????? A printf format string which contains the ascii name of

????????????? the port. Normally is set to "eth%d" which sets

????????????? eth0 for the first Ethernet,eth1 for the second etc.

?

????????????? CONFIG_CDP_CAPABILITIES

?

?????? ?????? A 32bit integer which indicates the device capabilities;

????????????? 0x00000010 for a normal host which does not forwards.

?

????????????? CONFIG_CDP_VERSION

?

????????????? An ascii string containing the version of the software.

?

????????????? CONFIG_CDP_PLATFORM

?

????????????? An ascii string containing the name of the platform.

?

????????????? CONFIG_CDP_TRIGGER

?

????????????? A 32bit integer sent on the trigger.

?

????????????? CONFIG_CDP_POWER_CONSUMPTION

?

????????????? A 16bit integer containing the power consumption of the

????????????? device in .1 of milliwatts.

?

????????????? CONFIG_CDP_APPLIANCE_VLAN_TYPE

?

????????????? A byte containing the id of the VLAN.

?

-???????? Status LED:???

-???????? 状态 LED

?????? CONFIG_STATUS_LED

?

????????????? Several configurations allow to display the current

????????????? status using a LED. For instance,the LED will blink

????????????? fast while running U-Boot code,stop blinking as

????????????? soon as a reply to a BOOTP request was received,and

????????????? start blinking slow once the Linux kernel is running

????????????? (supported by a status LED driver in the Linux

????????????? kernel). Defining CONFIG_STATUS_LED enables this

????????????? feature in U-Boot.

?

-???????? CAN Support:??????

-???????? CAN 总线支持

CONFIG_CAN_DRIVER

?

????????????? Defining CONFIG_CAN_DRIVER enables CAN driver support

????????????? on those systems that support this (optional)

????????????? feature,like the TQM8xxL modules.

?

-???????? I2C Support:

-???????? I2C 支持

? CONFIG_HARD_I2C | CONFIG_SOFT_I2C

?

????????????? These enable I2C serial bus commands. Defining either of

????????????? (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will

????????????? include the appropriate I2C driver for the selected CPU.

?????? 定义这两项将允许 I2C 串行总线命令。配置这两项将包含相应的驱动

?

????????????? This will allow you to use i2c commands at the u-boot

????????????? command line (as long as you set CONFIG_CMD_I2C in

????????????? CONFIG_COMMANDS) and communicate with i2c based realtime

????????????? clock chips. See common/cmd_i2c.c for a description of the

????????????? command line interface.

?

????????????? CONFIG_I2C_CMD_TREE is a recommended option that places

????????????? all I2C commands under a single 'i2c' root command.? The

????????????? older 'imm','imd','iprobe' etc. commands are considered

????????????? deprecated and may disappear in the future.

?

????????????? CONFIG_HARD_I2C selects a hardware I2C controller.

?

????????????? CONFIG_SOFT_I2C configures u-boot to use a software (aka

????????????? bit-banging) driver instead of CPM or similar hardware

????????????? support for I2C.

?

????????????? There are several other quantities that must also be

????????????? defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.

?

????????????? In both cases you will need to define CFG_I2C_SPEED

????????????? to be the frequency (in Hz) at which you wish your i2c bus

????????????? to run and CFG_I2C_SLAVE to be the address of this node (ie

????????????? the CPU's i2c node address).

?

????????????? Now,the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)

????????????? sets the CPU up as a master node and so its address should

????????????? therefore be cleared to 0 (See,eg,MPC823e User's Manual

????????????? p.16-473). So,set CFG_I2C_SLAVE to 0.

?

????????????? That's all that's required for CONFIG_HARD_I2C.

?

????????????? If you use the software i2c interface (CONFIG_SOFT_I2C)

????????????? then the following macros need to be defined (examples are

????????????? from include/configs/lwmon.h ):

????? ? 若用软件 I2C 接口，则下面的宏应被定义

?

?????? ?????? I2C_INIT

?

????????????? (Optional). Any commands necessary to enable the I2C

????????????? controller or configure ports.

?

????????????? eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |=?????? PB_SCL)

?

?????? ?????? I2C_PORT

?

????????????? (Only for MPC8260 CPU). The I/O port to use (the code

????????????? assumes both bits are on the same port). Valid values

????????????? are 0..3 for ports A..D.

?

????????????? I2C_ACTIVE

?

????????????? The code necessary to make the I2C data line active

????????????? (driven).? If the data line is open collector,this

????????????? define can be null.

????? ? 用来激活 I2C 数据线

?

????????????? eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |=? PB_SDA)

?

????????????? I2C_TRISTATE

?

????????????? The code necessary to make the I2C data line tri-stated

????????????? (inactive).? If the data line is open collector,this

????????????? define can be null.

?

????????????? eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)

?

????????????? I2C_READ

?

????????????? Code that returns TRUE if the I2C data line is high,

????????????? FALSE if it is low.

?????? 当 I2C 数据线为高则返回 TRUE ，为低则返回 FALSE

?

????????????? eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)

?

????????????? I2C_SDA(bit)

?

????????????? If <bit> is TRUE,sets the I2C data line high. If it

????????????? is FALSE,it clears it (low).

?????? Bit 为 TRUE 则设置 I2C 数据线为高

?

????????????? eg: #define I2C_SDA(bit) /

???????????????????? if(bit) immr->im_cpm.cp_pbdat |=? PB_SDA; /

???????????????????? else immr->im_cpm.cp_pbdat &= ~PB_SDA

?

????????????? I2C_SCL(bit)

?

????????????? If <bit> is TRUE,sets the I2C clock line high. If it

????????????? is FALSE,it clears it (low).

?????? Bit 为 TRUE 则设置 I2C 时钟线为高

?

????????????? eg: #define I2C_SCL(bit) /

???????????????????? if(bit) immr->im_cpm.cp_pbdat |=? PB_SCL; /

???????????????????? else immr->im_cpm.cp_pbdat &= ~PB_SCL

?

????????????? I2C_DELAY

?

????????????? This delay is invoked four times per clock cycle so this

????????????? controls the rate of data transfer.?

一个时钟周期调用四次延时，所以它决定了数据传输速率

The data rate thus is

数据速率为 1 / (I2C_DELAY * 4) . Often defined to be something

????????????? like:

?

????????????? #define I2C_DELAY? udelay(2)

?

????????????? CFG_I2C_INIT_BOARD

?

????????????? When a board is reset during an i2c bus transfer

????????????? chips might think that the current transfer is still

????????????? in progress. On some boards it is possible to access

????????????? the i2c SCLK line directly,either by using the

????????????? processor pin as a GPIO or by having a second pin

????????????? connected to the bus. If this option is defined a

????????????? custom i2c_init_board() routine in boards/xxx/board.c

????????????? is run early in the boot sequence.

?

????????????? CONFIG_I2CFAST (PPC405GP|PPC405EP only)

?

????????????? This option enables configuration of bi_iic_fast[] flags

????????????? in u-boot bd_info structure based on u-boot environment

????????????? variable "i2cfast". (see also i2cfast)

?

????????????? CONFIG_I2C_MULTI_BUS

?

????????????? This option allows the use of multiple I2C buses,each of which

????????????? must have a controller.? At any point in time,only one bus is

????????????? active.? To switch to a different bus,use the 'i2c dev' command.

????????????? Note that bus numbering is zero-based.

?????? 多 I2C 总线支持通过 'i2c dev' 命令切换

?

????????????? CFG_I2C_NOPROBES

?

????????????? This option specifies a list of I2C devices that will be skipped

????????????? when the 'i2c probe' command is issued (or 'iprobe' using the legacy

????????????? command).

?????? 当输入命令 'i2c probe' 时将跳过这些 I2C 设备

?

?If CONFIG_I2C_MULTI_BUS is set,specify a list of bus-device

????????????? pairs.????? Otherwise,specify a 1D array of device addresses

?

????????????? e.g.

???????????????????? #undef??? CONFIG_I2C_MULTI_BUS

???????????????????? #define CFG_I2C_NOPROBES????? {0x50,0x68}

??????

?

????????????? will skip addresses 0x50 and 0x68 on a board with one I2C bus

?? ???? 跳过地址 0x50 和 0x68

?

???????????????????? #define?? CONFIG_I2C_MULTI_BUS

???????????????????? #define CFG_I2C_MULTI_NOPROBES????? {{0,0x50},{0,0x68},{1,0x54}}

?

????????????? will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1

?????? 跳过总线 0 的地址 0x50 和 0x68 ，总线 1 的地址 0X54

?

????????????? CFG_SPD_BUS_NUM

?

????????????? If defined,then this indicates the I2C bus number for DDR SPD.

????????????? If not defined,then U-Boot assumes that SPD is on I2C bus 0.

?????? 指出 DDR SPD 所在 I2C 的总线，默认为 0 总线

?

????????????? CFG_RTC_BUS_NUM

?

????????????? If defined,then this indicates the I2C bus number for the RTC.

????????????? If not defined,then U-Boot assumes that RTC is on I2C bus 0.

?

????????????? CFG_DTT_BUS_NUM

?

????????????? If defined,then this indicates the I2C bus number for the DTT.

????????????? If not defined,then U-Boot assumes that DTT is on I2C bus 0.

?

????????????? CONFIG_FSL_I2C

?

????????????? Define this option if you want to use Freescale's I2C driver in

????????????? drivers/i2c/fsl_i2c.c .

????? ? 若用飞思卡尔的 I2C 驱动则定义

?

?

-???????? SPI Support:

-???????? SPI 支持

??? CONFIG_SPI

?

????????????? Enables SPI driver (so far only tested with

????????????? SPI EEPROM,also an instance works with Crystal A/D and

????????????? D/As on the SACSng board)

?

????????????? CONFIG_SPI_X

?

????????????? Enables extended (16-bit) SPI EEPROM addressing.

????????????? (symmetrical to CONFIG_I2C_X)

?

????????????? CONFIG_SOFT_SPI

?

????????????? Enables a software (bit-bang) SPI driver rather than

????????????? using hardware support. This is a general purpose

????????????? driver that only requires three general I/O port pins

????????????? (two outputs,one input) to function. If this is

????????????? defined,the board configuration must define several

????????????? SPI configuration items (port pins to use,etc). For

????????????? an example,see include/configs/sacsng.h.

?????? 允许不依赖硬件的软件 SPI 驱动，若想使用此项，则还在定义一些 SPI 配置选项，如 IO 管脚等，查看 include/configs/sacsng.h.

?

????????????? CONFIG_HARD_SPI

?

????????????? Enables a hardware SPI driver for general-purpose reads

????????????? and writes.? As with CONFIG_SOFT_SPI,the board configuration

????????????? must define a list of chip-select function pointers.

????????????? Currently supported on some MPC8xxx processors.? For an

????????????? example,see include/configs/mpc8349emds.h.

?

????????????? CONFIG_MXC_SPI

?

????????????? Enables the driver for the SPI controllers on i.MX and MXC

????????????? SoCs. Currently only i.MX31 is supported.

?

-???????? FPGA Support:

-???????? FPGA 支持

CONFIG_FPGA

?

????????????? Enables FPGA subsystem.

?

????????????? CONFIG_FPGA_<vendor>

?

????????????? Enables support for specific chip vendors.

????????????? (ALTERA,XILINX)

?

????????????? CONFIG_FPGA_<family>

?

????????????? Enables support for FPGA family.

????????????? (SPARTAN2,SPARTAN3,VIRTEX2,CYCLONE2,ACEX1K,ACEX)

?

????????????? CONFIG_FPGA_COUNT

?

????????????? Specify the number of FPGA devices to support.

?

????????????? CFG_FPGA_PROG_FEEDBACK

?

????????????? Enable printing of hash marks during FPGA configuration.

?

????????????? CFG_FPGA_CHECK_BUSY

?

????????????? Enable checks on FPGA configuration interface busy

????????????? status by the configuration function. This option

????????????? will require a board or device specific function to

????????????? be written.

?

????????????? CONFIG_FPGA_DELAY

?

????????????? If defined,a function that provides delays in the FPGA

????????????? configuration driver.

?

????????????? CFG_FPGA_CHECK_CTRLC

????????????? Allow Control-C to interrupt FPGA configuration

?

????????????? CFG_FPGA_CHECK_ERROR

?

????????????? Check for configuration errors during FPGA bitfile

????????????? loading. For example,abort during Virtex II

????????????? configuration if the INIT_B line goes low (which

????????????? indicated a CRC error).

?

????????????? CFG_FPGA_WAIT_INIT

?

????????????? Maximum time to wait for the INIT_B line to deassert

????????????? after PROB_B has been deasserted during a Virtex II

????????????? FPGA configuration sequence. The default time is 500

????????????? ms.

?

????????????? CFG_FPGA_WAIT_BUSY

?

????????????? Maximum time to wait for BUSY to deassert during

????????????? Virtex II FPGA configuration. The default is 5 ms.

?

????????????? CFG_FPGA_WAIT_CONFIG

?

????????????? Time to wait after FPGA configuration. The default is

????????????? 200 ms.

?

-???????? Configuration Management:

-???????? 结构管理

????????????? CONFIG_IDENT_STRING

?

????????????? If defined,this string will be added to the U-Boot

????????????? version information (U_BOOT_VERSION)

?????? 定义的字符串将出现在 UBOOT 版本信息里

?

- Vendor Parameter Protection:

卖主参数保护

?

????????????? U-Boot considers the values of the environment

????????????? variables "serial#" (Board Serial Number) and

????????????? "ethaddr" (Ethernet Address) to be parameters that

????????????? are set once by the board vendor / manufacturer,and

????????????? protects these variables from casual modification by

????????????? the user. Once set,these variables are read-only,

????????????? and write or delete attempts are rejected.

UBOOT 把环境变量 "serial#" 和 "ethaddr" 当作板卖主或是制造商一次性写入的，为防止用户偶然性的更改而对这些变量加以保护，一旦设置，这些变量就为只读，所有写入或删除操作将被拒绝

You can change this behaviour:

?

????????????? If CONFIG_ENV_OVERWRITE is #defined in your config

????????????? file,the write protection for vendor parameters is

????????????? completely disabled. Anybody can change or delete

????????????? these parameters.

????? ? 一旦 CONFIG_ENV_OVERWRITE 在配置文件中被定义，则所有卖主参数的写保护都被禁止，任何人可以进行更改和读写

?

????????????? Alternatively,if you #define _both_ CONFIG_ETHADDR

????????????? _and_ CONFIG_OVERWRITE_ETHADDR_ONCE,a default

????????????? Ethernet address is installed in the environment,

????????????? which can be changed exactly ONCE by the user. [The

????????????? serial# is unaffected by this,i. e. it remains

????????????? read-only.]

?

-???????? Protected RAM:

-???????? 保护 RAM

????????????? CONFIG_PRAM

?

????????????? Define this variable to enable the reservation of

????????????? "protected RAM",i. e. RAM which is not overwritten

????????????? by U-Boot.

保护的 RAM 将不会被 UBOOT 覆盖

Define CONFIG_PRAM to hold the number of

????????????? kB you want to reserve for pRAM.

?????? 定义你想保护的字节大小，单位为 KB

You can overwrite

????????????? this default value by defining an environment

????????????? variable "pram" to the number of kB you want to

????????????? reserve. Note that the board info structure will

????????????? still show the full amount of RAM. If pRAM is

????????????? reserved,a new environment variable "mem" will

????????????? automatically be defined to hold the amount of

????????????? remaining RAM in a form that can be passed as boot

????????????? argument to Linux,for instance like that:

?

???????????????????? setenv bootargs ... mem=/${mem}

???????????????????? saveenv

?

????????????? This way you can tell Linux not to use this memory,

????????????? either,which results in a memory region that will

????????????? not be affected by reboots.

?

????????????? *WARNING* If your board configuration uses automatic

????????????? detection of the RAM size,you must make sure that

????????????? this memory test is non-destructive.

? 若板子配置为自动检测 RAM 大小，请确保检测是无损的

?So far,the

????????????? following board configurations are known to be

????????????? "pRAM-clean":

?

???????????????????? ETX094,IVMS8,IVML24,SPD8xx,TQM8xxL,

???????????????????? HERMES,IP860,RPXlite,LWMON,LANTEC,

???????????????????? PCU_E,FLAGADM,TQM8260

?

-???????? Error Recovery:

-???????? 错误纠正

????????????? CONFIG_PANIC_HANG

?

????????????? Define this variable to stop the system in case of a

????????????? fatal error,so that you have to reset it manually.

??? ??? 一旦发生错误就停止系统，并要手动重启

????????????? This is probably NOT a good idea for an embedded

????????????? system where you want the system to reboot

????????????? automatically as fast as possible,but it may be

????????????? useful during development since you can try to debug

????????????? the conditions that lead to the situation.

?

????????????? CONFIG_NET_RETRY_COUNT

?

????????????? This variable defines the number of retries for

????????????? network operations like ARP,RARP,TFTP,or BOOTP

????????????? before giving up the operation. If not defined,a

????????????? default value of 5 is used.

?????? 定义网络操作的重试次数，默认为 5

?

????????????? CONFIG_ARP_TIMEOUT

?

????????????? Timeout waiting for an ARP reply in milliseconds.

?

-???????? Command Interpreter:

-???????? 命令解释

????????????? CONFIG_AUTO_COMPLETE

?

????????????? Enable auto completion of commands using TAB.

?????? 允许用 TAB 来自动完成命令

?

????????????? Note that this feature has NOT been implemented yet

????????????? for the "hush" shell.

?

?

????????????? CFG_HUSH_PARSER

?

????????????? Define this variable to enable the "hush" shell (from

????????????? Busybox) as command line interpreter,thus enabling

????????????? powerful command line syntax like

????????????? if...then...else...fi conditionals or `&&' and '||'

????????????? constructs ("shell scripts").

?

????????????? If undefined,you get the old,much simpler behaviour

????????????? with a somewhat smaller memory footprint.

?

?

????????????? CFG_PROMPT_HUSH_PS2

?

????????????? This defines the secondary prompt string,which is

????????????? printed when the command interpreter needs more input

????????????? to complete a command. Usually "> ".

?????? 定义命令行的第二个提示符

?

?????? Note:

?

????????????? In the current implementation,the local variables

????????????? space and global environment variables space are

????????????? separated. Local variables are those you define by

????????????? simply typing `name=value'. To access a local

????????????? variable later on,you have write `$name' or

????????????? `${name}'; to execute the contents of a variable

????????????? directly type `$name' at the command prompt.

????? ? 目前本地变量空间和全局环境变量空间是分开的，本地变量是通过

`name=value' 定义的，可通过 `$name' 或 `${name}' 来访问，在命令提示符下输入 `$name' 来访问变量内容

????????????? Global environment variables are those you use

????????????? setenv/printenv to work with. To run a command stored

????????????? in such a variable,you need to use the run command,

????????????? and you must not use the '$' sign to access them.

?????? 全局环境变量是通过 setenv/printenv 来运行和访问的

?

????????????? To store commands and special characters in a

????????????? variable,please use double quotation marks

????????????? surrounding the whole text of the variable,instead

????????????? of the backslashes before semicolons and special

????????????? symbols.

?

- Commandline Editing and History:

????????????? CONFIG_CMDLINE_EDITING

?

????????????? Enable editing and History functions for interactive

????????????? commandline input operations

?

- Default Environment:

????????????? CONFIG_EXTRA_ENV_SETTINGS

?

????????????? Define this to contain any number of null terminated

????????????? strings (variable = value pairs) that will be part of

????????????? the default environment compiled into the boot image.

?

????????????? For example,place something like this in your

????????????? board's config file:

?

????????????? #define CONFIG_EXTRA_ENV_SETTINGS /

???????????????????? "myvar1=value1/0" /

???????????????????? "myvar2=value2/0"

?

????????????? Warning: This method is based on knowledge about the

????????????? internal format how the environment is stored by the

????????????? U-Boot code. This is NOT an official,exported

????????????? interface! Although it is unlikely that this format

????????????? will change soon,there is no guarantee either.

????????????? You better know what you are doing here.

?

????????????? Note: overly (ab)use of the default environment is

????????????? discouraged. Make sure to check other ways to preset

????????????? the environment like the autoscript function or the

????????????? boot command first.

?

-???????? DataFlash Support:

-???????? 数据 Flash 支持

????????????? CONFIG_HAS_DATAFLASH

?

????????????? Defining this option enables DataFlash features and

????????????? allows to read/write in Dataflash via the standard

????????????? commands cp,md...

?????? 定义此项来允许数据 Flash 特性，如 cp,md 命令

?

- SystemACE Support:

????????????? CONFIG_SYSTEMACE

?

????????????? Adding this option adds support for Xilinx SystemACE

????????????? chips attached via some sort of local bus. The address

????????????? of the chip must also be defined in the

????????????? CFG_SYSTEMACE_BASE macro. For example:

?

????????????? #define CONFIG_SYSTEMACE

????????????? #define CFG_SYSTEMACE_BASE 0xf0000000

?

????????????? When SystemACE support is added,the "ace" device type

????????????? becomes available to the fat commands,i.e. fatls.

?

-???????? TFTP Fixed UDP Port:

-???????? TFTP 固定 UDP 端口

????????????? CONFIG_TFTP_PORT

?

????????????? If this is defined,the environment variable tftpsrcp

????????????? is used to supply the TFTP UDP source port value.

????????????? If tftpsrcp isn't defined,the normal pseudo-random port

????????????? number generator is used.

?????? 若被定义则环境变量 tftpsrcp 用来提供 TFTP UDP 源端口值，

若 tftpsrcp 没被定义则默认一个伪随机端口

?

????????????? Also,the environment variable tftpdstp is used to supply

????????????? the TFTP UDP destination port value.? If tftpdstp isn't

????????????? defined,the normal port 69 is used.

?????? Tftpdstp 环境变来用来指定目的端口，若不定义则默认 69

?

????????????? The purpose for tftpsrcp is to allow a TFTP server to

????????????? blindly start the TFTP transfer using the pre-configured

????????????? target IP address and UDP port. This has the effect of

????????????? "punching through" the (Windows XP) firewall,allowing

????????????? the remainder of the TFTP transfer to proceed normally.

????????????? A better solution is to properly configure the firewall,

????????????? but sometimes that is not allowed.

?

-???????? Show boot progress:

-???????? 显示 BOOT 过程

????????????? CONFIG_SHOW_BOOT_PROGRESS

?

????????????? Defining this option allows to add some board-

????????????? specific code (calling a user-provided function

????????????? "show_boot_progress(int)") that enables you to show

????????????? the system's boot progress on some display (for

????????????? example,some LED's) on your board. At the moment,

????????????? the following checkpoints are implemented:

?????? 允许用户通过调用函数 "show_boot_progress(int)" 在特定设备显示系统启动过程，此刻下面的检查点将被执行

?

Legacy uImage format:

?

? Arg??? Where????????????????? When

??? 1??? common/cmd_bootm.c?????? before attempting to boot an image

?? -1???? common/cmd_bootm.c?????? Image header has bad? magic number

??? 2??? common/cmd_bootm.c?????? Image header has correct magic number

?? -2???? common/cmd_bootm.c?????? Image header has bad? checksum

??? 3??? common/cmd_bootm.c?????? Image header has correct checksum

?? -3???? common/cmd_bootm.c?????? Image data?? has bad checksum

??? 4??? common/cmd_bootm.c?????? Image data?? has correct checksum

?? -4???? common/cmd_bootm.c?????? Image is for unsupported architecture

??? 5??? common/cmd_bootm.c?????? Architecture check OK

?? -5???? common/cmd_bootm.c?????? Wrong Image Type (not kernel,multi)

??? 6??? common/cmd_bootm.c?????? Image Type check OK

?? -6???? common/cmd_bootm.c?????? gunzip uncompression error

?? -7???? common/cmd_bootm.c?????? Unimplemented compression type

??? 7??? common/cmd_bootm.c?????? Uncompression OK

??? 8??? common/cmd_bootm.c?????? No uncompress/copy overwrite error

?? -9???? common/cmd_bootm.c?????? Unsupported OS (not Linux,BSD,VxWorks,QNX)

?

??? 9??? common/image.c????????? Start initial ramdisk verification

? -10???? common/image.c????????? Ramdisk header has bad???? ?? magic number

? -11???? common/image.c????????? Ramdisk header has bad???? ?? checksum

?? 10??? common/image.c????????? Ramdisk header is OK

? -12???? common/image.c????????? Ramdisk data?? has bad??? ?? checksum

?? 11??? common/image.c????????? Ramdisk data?? has correct checksum

?? 12??? common/image.c????????? Ramdisk verification complete,start loading

? -13???? common/image.c????????? Wrong Image Type (not PPC Linux ramdisk)

?? 13??? common/image.c????????? Start multifile image verification

?? 14??? common/image.c????????? No initial ramdisk,no multifile,continue.

?

?? 15??? lib_<arch>/bootm.c???? All preparation done,transferring control to OS

?

? -30???? lib_ppc/board.c?????????? Fatal error,hang the system

? -31???? post/post.c?????????? POST test failed,detected by post_output_backlog()

? -32???? post/post.c?????????? POST test failed,detected by post_run_single()

?

?? 34??? common/cmd_doc.c??? before loading a Image from a DOC device

? -35???? common/cmd_doc.c??? Bad usage of "doc" command

?? 35??? common/cmd_doc.c??? correct usage of "doc" command

? -36???? common/cmd_doc.c??? No boot device

?? 36??? common/cmd_doc.c??? correct boot device

? -37???? common/cmd_doc.c??? Unknown Chip ID on boot device

?? 37??? common/cmd_doc.c??? correct chip ID found,device available

? -38???? common/cmd_doc.c??? Read Error on boot device

?? 38??? common/cmd_doc.c??? reading Image header from DOC device OK

? -39???? common/cmd_doc.c??? Image header has bad magic number

?? 39??? common/cmd_doc.c??? Image header has correct magic number

? -40???? common/cmd_doc.c??? Error reading Image from DOC device

?? 40??? common/cmd_doc.c??? Image header has correct magic number

?? 41??? common/cmd_ide.c???? before loading a Image from a IDE device

? -42???? common/cmd_ide.c???? Bad usage of "ide" command

?? 42??? common/cmd_ide.c???? correct usage of "ide" command

? -43???? common/cmd_ide.c???? No boot device

?? 43??? common/cmd_ide.c???? boot device found

? -44???? common/cmd_ide.c???? Device not available

?? 44??? common/cmd_ide.c???? Device available

? -45???? common/cmd_ide.c???? wrong partition selected

?? 45??? common/cmd_ide.c???? partition selected

? -46???? common/cmd_ide.c???? Unknown partition table

?? 46??? common/cmd_ide.c???? valid partition table found

? -47???? common/cmd_ide.c???? Invalid partition type

?? 47??? common/cmd_ide.c???? correct partition type

? -48???? common/cmd_ide.c???? Error reading Image Header on boot device

?? 48??? common/cmd_ide.c???? reading Image Header from IDE device OK

? -49???? common/cmd_ide.c???? Image header has bad magic number

?? 49??? common/cmd_ide.c???? Image header has correct magic number

? -50???? common/cmd_ide.c???? Image header has bad? checksum

?? 50??? common/cmd_ide.c???? Image header has correct checksum

? -51???? common/cmd_ide.c???? Error reading Image from IDE device

?? 51??? common/cmd_ide.c???? reading Image from IDE device OK

?? 52??? common/cmd_nand.c?? before loading a Image from a NAND device

? -53???? common/cmd_nand.c?? Bad usage of "nand" command

?? 53??? common/cmd_nand.c?? correct usage of "nand" command

? -54???? common/cmd_nand.c?? No boot device

?? 54??? common/cmd_nand.c?? boot device found

? -55???? common/cmd_nand.c?? Unknown Chip ID on boot device

?? 55??? common/cmd_nand.c?? correct chip ID found,device available

? -56???? common/cmd_nand.c?? Error reading Image Header on boot device

?? 56??? common/cmd_nand.c?? reading Image Header from NAND device OK

? -57???? common/cmd_nand.c?? Image header has bad magic number

?? 57??? common/cmd_nand.c?? Image header has correct magic number

? -58???? common/cmd_nand.c?? Error reading Image from NAND device

?? 58??? common/cmd_nand.c?? reading Image from NAND device OK

?

? -60???? common/env_common.c???? Environment has a bad CRC,using default

?

?? 64??? net/eth.c??????? starting with Ethernet configuration.

? -64???? net/eth.c??????? no Ethernet found.

?? 65??? net/eth.c??????? Ethernet found.

?

? -80???? common/cmd_net.c???? usage wrong

?? 80??? common/cmd_net.c???? before calling NetLoop()

? -81???? common/cmd_net.c???? some error in NetLoop() occurred

?? 81??? common/cmd_net.c???? NetLoop() back without error

? -82???? common/cmd_net.c???? size == 0 (File with size 0 loaded)

?? 82??? common/cmd_net.c???? trying automatic boot

?? 83??? common/cmd_net.c???? running autoscript

? -83???? common/cmd_net.c???? some error in automatic boot or autoscript

?? 84??? common/cmd_net.c???? end without errors

?

FIT uImage format:

?

? Arg??? Where????????????????? When

? 100??? common/cmd_bootm.c?????? Kernel FIT Image has correct format

?-100???? common/cmd_bootm.c?????? Kernel FIT Image has incorrect format

? 101??? common/cmd_bootm.c?????? No Kernel subimage unit name,using configuration

?-101???? common/cmd_bootm.c?????? Can't get configuration for kernel subimage

? 102??? common/cmd_bootm.c?????? Kernel unit name specified

?-103???? common/cmd_bootm.c?????? Can't get kernel subimage node offset

? 103??? common/cmd_bootm.c?????? Found configuration node

? 104??? common/cmd_bootm.c?????? Got kernel subimage node offset

?-104???? common/cmd_bootm.c?????? Kernel subimage hash verification failed

? 105??? common/cmd_bootm.c?????? Kernel subimage hash verification OK

?-105???? common/cmd_bootm.c?????? Kernel subimage is for unsupported architecture

? 106??? common/cmd_bootm.c?????? Architecture check OK

?-106???? common/cmd_bootm.c?????? Kernel subimage has wrong type

? 107??? common/cmd_bootm.c?????? Kernel subimage type OK

?-107???? common/cmd_bootm.c?????? Can't get kernel subimage data/size

? 108??? common/cmd_bootm.c?????? Got kernel subimage data/size

?-108???? common/cmd_bootm.c?????? Wrong image type (not legacy,FIT)

?-109???? common/cmd_bootm.c?????? Can't get kernel subimage type

?-110???? common/cmd_bootm.c?????? Can't get kernel subimage comp

?-111???? common/cmd_bootm.c?????? Can't get kernel subimage os

?-112???? common/cmd_bootm.c?????? Can't get kernel subimage load address

?-113???? common/cmd_bootm.c?????? Image uncompress/copy overwrite error

?

? 120??? common/image.c????????? Start initial ramdisk verification

?-120???? common/image.c????????? Ramdisk FIT image has incorrect format

? 121??? common/image.c????????? Ramdisk FIT image has correct format

? 122??? common/image.c????????? No ramdisk subimage unit name,using configuration

?-122???? common/image.c????????? Can't get configuration for ramdisk subimage

? 123??? common/image.c????????? Ramdisk unit name specified

?-124???? common/image.c????????? Can't get ramdisk subimage node offset

? 125??? common/image.c????????? Got ramdisk subimage node offset

?-125???? common/image.c????????? Ramdisk subimage hash verification failed

? 126??? common/image.c????????? Ramdisk subimage hash verification OK

?-126???? common/image.c????????? Ramdisk subimage for unsupported architecture

? 127??? common/image.c????????? Architecture check OK

?-127???? common/image.c????????? Can't get ramdisk subimage data/size

? 128??? common/image.c????????? Got ramdisk subimage data/size

? 129??? common/image.c????????? Can't get ramdisk load address

?-129???? common/image.c????????? Got ramdisk load address

?

?-130???? common/cmd_doc.c??? Incorrect FIT image format

? 131??? common/cmd_doc.c??? FIT image format OK

?

?-140???? common/cmd_ide.c???? Incorrect FIT image format

? 141??? common/cmd_ide.c???? FIT image format OK

?

?-150???? common/cmd_nand.c?? Incorrect FIT image format

? 151??? common/cmd_nand.c?? FIT image format OK

?

?

Modem Support:

调制解调器支持

--------------

?

[so far only for SMDK2400 and TRAB boards]

目前只支持 SMDK2400 和 TRAB 板

?

- Modem support enable:

????????????? CONFIG_MODEM_SUPPORT

?

- RTS/CTS Flow control enable:

????????????? CONFIG_HWFLOW

?

- Modem debug support:

????????????? CONFIG_MODEM_SUPPORT_DEBUG

?

????????????? Enables debugging stuff (char screen[1024],dbg())

????????????? for modem support. Useful only with BDI2000.

?

-???????? Interrupt support (PPC):

-???????? 中断支持（ PPC ）

?

????????????? There are common interrupt_init() and timer_interrupt()

????????????? for all PPC archs. interrupt_init() calls interrupt_init_cpu()

????????????? for CPU specific initialization. interrupt_init_cpu()

????????????? should set decrementer_count to appropriate value. If

????????????? CPU resets decrementer automatically after interrupt

????????????? (ppc4xx) it should set decrementer_count to zero.

????????????? timer_interrupt() calls timer_interrupt_cpu() for CPU

????????????? specific handling. If board has watchdog / status_led

????????????? / other_activity_monitor it works automatically from

????????????? general timer_interrupt().

?

- General:

?

????????????? In the target system modem support is enabled when a

????????????? specific key (key combination) is pressed during

????????????? power-on. Otherwise U-Boot will boot normally

????????????? (autoboot). The key_pressed() function is called from

????????????? board_init(). Currently key_pressed() is a dummy

????????????? function,returning 1 and thus enabling modem

????????????? initialization.

?

????????????? If there are no modem init strings in the

????????????? environment,U-Boot proceed to autoboot; the

????????????? previous output (banner,info printfs) will be

????????????? suppressed,though.

?

????????????? See also: doc/README.Modem

?

?

Configuration Settings:

配置设置

-----------------------

?

- CFG_LONGHELP: Defined when you want long help messages included;

????????????? undefine this when you're short of memory.

?????? 当需要较长的帮助时就定义此项，若内存太小就不要定义

?

- CFG_PROMPT:?????? This is what U-Boot prints on the console to

????????????? prompt for user input.

?????? UBOOT 打印到控制台的输入提示

?

- CFG_CBSIZE:? Buffer size for input from the Console

?????? 控制台输入的缓存大小

?

- CFG_PBSIZE:? Buffer size for Console output

?????? 控制台输出的缓存大小

?

- CFG_MAXARGS:?? max. Number of arguments accepted for monitor commands

?????? 监控器接受的最大参数数量

?

- CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to

????????????? the application (usually a Linux kernel) when it is

????????????? booted

?????? 传入应用程序的启动参数的缓存的大小

?

- CFG_BAUDRATE_TABLE:

????????????? List of legal baudrate settings for this board.

?????? 此板所有合法的波特率

?

- CFG_CONSOLE_INFO_QUIET

????????????? Suppress display of console information at boot.

?????? 禁止显示启动信息

?

- CFG_CONSOLE_IS_IN_ENV

????????????? If the board specific function

???????????????????? extern int overwrite_console (void);

????????????? returns 1,the stdin,stderr and stdout are switched to the

????????????? serial port,else the settings in the environment are used.

?????? 若函数 extern int overwrite_console (void) 返回 1 ，则 stdin,stderr 和 stdout

?????? 转接到串口，否则环境中的设置将被应用

?

- CFG_CONSOLE_OVERWRITE_ROUTINE

????????????? Enable the call to overwrite_console().

?????? 允许调用 overwrite_console()

?

- CFG_CONSOLE_ENV_OVERWRITE

????????????? Enable overwrite of previous console environment settings.

?? ??????? 允许覆盖以前的控制台环境设置

?

- CFG_MEMTEST_START,CFG_MEMTEST_END:

????????????? Begin and End addresses of the area used by the

????????????? simple memory test.

?????? 用来简单内存测试地区的起始和结束地址

?

- CFG_ALT_MEMTEST:

????????????? Enable an alternate,more extensive memory test.

?

- CFG_MEMTEST_SCRATCH:

????????????? Scratch address used by the alternate memory test

????????????? You only need to set this if address zero isn't writeable

?

- CFG_MEM_TOP_HIDE (PPC only):

????????????? If CFG_MEM_TOP_HIDE is defined in the board config header,

????????????? this specified memory area will get subtracted from the top

????????????? (end) of RAM and won't get "touched" at all by U-Boot. By

????????????? fixing up gd->ram_size the Linux kernel should gets passed

????????????? the now "corrected" memory size and won't touch it either.

????????????? This should work for arch/ppc and arch/powerpc. Only Linux

????????????? board ports in arch/powerpc with bootwrapper support that

????????????? recalculate the memory size from the SDRAM controller setup

????????????? will have to get fixed in Linux additionally.

?

????????????? This option can be used as a workaround for the 440EPx/GRx

????????????? CHIP 11 errata where the last 256 bytes in SDRAM shouldn't

????????????? be touched.

?

????????????? WARNING: Please make sure that this value is a multiple of

????????????? the Linux page size (normally 4k). If this is not the case,

????????????? then the end address of the Linux memory will be located at a

????????????? non page size aligned address and this could cause major

????????????? problems.

?

- CFG_TFTP_LOADADDR:

????????????? Default load address for network file downloads

?????? 网络文件下载的默认加载地址

?

- CFG_LOADS_BAUD_CHANGE:

????????????? Enable temporary baudrate change while serial download

?????? 在串口下载时允许暂时改变波特率

?

- CFG_SDRAM_BASE:

????????????? Physical start address of SDRAM. _Must_ be 0 here.

????? ?SDRAM 的物理开始地址

?

- CFG_MBIO_BASE:

????????????? Physical start address of Motherboard I/O (if using a

????????????? Cogent motherboard)

?????? 主板 I/O 物理起始地址

?

- CFG_FLASH_BASE:

????????????? Physical start address of Flash memory.

?????? Flash 的物理起始地址

?

- CFG_MONITOR_BASE:

????????????? Physical start address of boot monitor code (set by

????????????? make config files to be same as the text base address

????????????? (TEXT_BASE) used when linking) - same as

????????????? CFG_FLASH_BASE when booting from flash.

?????? 启动监视器代码的物理起始地址，

当从 flash 启动时同 CFG_FLASH_BASE

?

- CFG_MONITOR_LEN:

????????????? Size of memory reserved for monitor code,used to

????????????? determine _at_compile_time_ (!) if the environment is

????????????? embedded within the U-Boot image,or in a separate

????????????? flash sector.

?????? 保存监视器代码的储存器大小

?

- CFG_MALLOC_LEN:

????????????? Size of DRAM reserved for malloc() use.

?????? DRAM 中保留为 malloc() 所用的大小

?

- CFG_BOOTM_LEN:

????????????? Normally compressed uImages are limited to an

????????????? uncompressed size of 8 MBytes. If this is not enough,

????????????? you can define CFG_BOOTM_LEN in your board config file

????????????? to adjust this setting to your needs.

?????? 对压缩映像解压后大小的限制，默认为 8MB

?

- CFG_BOOTMAPSZ:

????????????? Maximum size of memory mapped by the startup code of

????????????? the Linux kernel; all data that must be processed by

????????????? the Linux kernel (bd_info,boot arguments,FDT blob if

????????????? used) must be put below this limit,unless "bootm_low"

????????????? enviroment variable is defined and non-zero. In such case

????????????? all data for the Linux kernel must be between "bootm_low"

????????????? and "bootm_low" + CFG_BOOTMAPSZ.

?????? Linux 内核启动代码所映射的最大内存空间

?

- CFG_MAX_FLASH_BANKS:

????????????? Max number of Flash memory banks

?????? 最大的 Flash bank 数量

?

- CFG_MAX_FLASH_SECT:

????????????? Max number of sectors on a Flash chip

?????? Flash 芯片的最大分区

?

- CFG_FLASH_ERASE_TOUT:

????????????? Timeout for Flash erase operations (in ms)

?????? Flash 擦除超时时间，单位 ms

?

- CFG_FLASH_WRITE_TOUT:

????????????? Timeout for Flash write operations (in ms)

?????? Flash 写入超时时间，单位 ms

?

- CFG_FLASH_LOCK_TOUT

????????????? Timeout for Flash set sector lock bit operation (in ms)

?????? Flash 设置 lock 位超时时间

?

- CFG_FLASH_UNLOCK_TOUT

????????????? Timeout for Flash clear lock bits operation (in ms)

?????? 清楚 LOCK 超时时间

?

- CFG_FLASH_PROTECTION

????????????? If defined,hardware flash sectors protection is used

????????????? instead of U-Boot software protection.

????? ? 定义硬件 FLASH 段保护

?

- CFG_DIRECT_FLASH_TFTP:

?

????????????? Enable TFTP transfers directly to flash memory;

?????? 允许 TFTP 直接传输到 flash

????????????? without this option such a download has to be

????????????? performed in two steps: (1) download to RAM,and (2)

????????????? copy from RAM to flash.

?????? 否则先要下到 RAM 再有 RAM 拷贝到 flash

?

????????????? The two-step approach is usually more reliable,since

????????????? you can check if the download worked before you erase

????????????? the flash,but in some situations (when system RAM is

????????????? too limited to allow for a temporary copy of the

????????????? downloaded image) this option may be very useful.

?????? 分两步将更可靠，因为你可以在下载前先检查是否擦除了 flash

?

- CFG_FLASH_CFI:

????????????? Define if the flash driver uses extra elements in the

????????????? common flash structure for storing flash geometry.

?

- CFG_FLASH_CFI_DRIVER

????????????? This option also enables the building of the cfi_flash driver

????????????? in the drivers directory

?

- CFG_FLASH_USE_BUFFER_WRITE

????????????? Use buffered writes to flash.

?????? 利用缓存写 flash

?

- CONFIG_FLASH_SPANSION_S29WS_N

????????????? s29ws-n MirrorBit flash has non-standard addresses for buffered

????????????? write commands.

?

- CFG_FLASH_QUIET_TEST

????????????? If this option is defined,the common CFI flash doesn't

????????????? print it's warning upon not recognized FLASH banks.

定义在识别 FLASH banks 之前打印通用 CFI flash 警告信息

This

????????????? is useful,if some of the configured banks are only

????????????? optionally available.

?

- CONFIG_FLASH_SHOW_PROGRESS

????????????? If defined (must be an integer),print out countdown

????????????? digits and dots.

?????? 定义打印出计数数字和点

Recommended value: 45 (9..1) for 80

????????????? column displays,15 (3..1) for 40 column displays.

?

- CFG_RX_ETH_BUFFER:

????????????? Defines the number of Ethernet receive buffers.

?????? 定义以太网接受缓存

On some

????????????? Ethernet controllers it is recommended to set this value

????????????? to 8 or even higher (EEPRO100 or 405 EMAC),since all

????????????? buffers can be full shortly after enabling the interface

????????????? on high Ethernet traffic.

????????????? Defaults to 4 if not defined.

?

The following definitions that deal with the placement and management

of environment data (variable area);

下面为设置环境变量

in general,we support the following configurations:

?

- CFG_ENV_IS_IN_FLASH:

?

?????? Define this if the environment is in flash memory.

??? 若环境变量在 FLASH 中就定义此项

?

?????? a) The environment occupies one whole flash sector,which is

?????? ?? "embedded" in the text segment with the U-Boot code.

环境占用了 flash 的一个整段

This

?????? ?? happens usually with "bottom boot sector" or "top boot

?????? ?? sector" type flash chips,which have several smaller

?????? ?? sectors at the start or the end. For instance,such a

?????? ?? layout can have sector sizes of 8,2x4,Nx32 kB. In

?????? ?? such a case you would place the environment in one of the

?????? ?? 4 kB sectors - with U-Boot code before and after it. With

?????? ?? "top boot sector" type flash chips,you would put the

?????? ?? environment in one of the last sectors,leaving a gap

?????? ?? between U-Boot and the environment.

????? 将环境放在最后一个分区中，在 UBOOT 和环境变量中哦国内留出间隙

?

?????? - CFG_ENV_OFFSET:

?

?????? ?? Offset of environment data (variable area) to the

?????? ?? beginning of flash memory; for instance,with bottom boot

?????? ?? type flash chips the second sector can be used: the offset

?????? ?? for this sector is given here.

?

?????? ?? CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.

?

?????? - CFG_ENV_ADDR:

?

?????? ?? This is just another way to specify the start address of

?????? ?? the flash sector containing the environment (instead of

?????? ?? CFG_ENV_OFFSET).

?????? 指定包含环境的 FLASH 段的开始地址

?

?????? - CFG_ENV_SECT_SIZE:

?

?????? ?? Size of the sector containing the environment.

??? ??? 环境段的大小

?

?

?????? b) Sometimes flash chips have few,equal sized,BIG sectors.

?????? ?? In such a case you don't want to spend a whole sector for

?????? ?? the environment.

?

?????? - CFG_ENV_SIZE:

?

?????? ?? If you use this in combination with CFG_ENV_IS_IN_FLASH

?????? ?? and CFG_ENV_SECT_SIZE,you can specify to use only a part

?????? ?? of this flash sector for the environment. This saves

?????? ?? memory for the RAM copy of the environment.

?????? 联合 CFG_ENV_IS_IN_FLASH 和 CFG_ENV_SECT_SIZE 就能指定段中的一部分用来设置环境

?

?????? ?? It may also save flash memory if you decide to use this

?????? ?? when your environment is "embedded" within U-Boot code,

?????? ?? since then the remainder of the flash sector could be used

?????? ?? for U-Boot code.

但你的环境变量嵌在 UBOOT 代码中，而你决定使用这个的话，它可以保存 flash 存储器

It should be pointed out that this is

?????? ?? STRONGLY DISCOURAGED from a robustness point of view:

?????? ?? updating the environment in flash makes it always

?????? ?? necessary to erase the WHOLE sector. If something goes

?????? ?? wrong before the contents has been restored from a copy in

?????? ?? RAM,your target system will be dead.

?

?????? - CFG_ENV_ADDR_REDUND

?????? ? CFG_ENV_SIZE_REDUND

?

?????? ?? These settings describe a second storage area used to hold

?????? ?? a redundant copy of the environment data,so that there is

?????? ?? a valid backup copy in case there is a power failure during

?????? ?? a "saveenv" operation.

?????? 第二个储存环境变量的空间，用来作为备份

?

BE CAREFUL! Any changes to the flash layout,and some changes to the

source code will make it necessary to adapt <board>/u-boot.lds*

accordingly!

?

?

- CFG_ENV_IS_IN_NVRAM:

?

?????? Define this if you have some non-volatile memory device

?????? (NVRAM,battery buffered SRAM) which you want to use for the

?????? environment.

??? 若将环境变量保存到非易失性 RAM 中，定义此项

?

?????? - CFG_ENV_ADDR:

?????? - CFG_ENV_SIZE:

?

?????? ? These two #defines are used to determine the memory area you

?????? ? want to use for environment. It is assumed that this memory

?????? ? can just be read and written to,without any special

?????? ? provision.

????? 定义用作环境变量的储存器地址和大小

?

BE CAREFUL! The first access to the environment happens quite early

in U-Boot initalization (when we try to get the setting of for the

console baudrate). You *MUST* have mapped your NVRAM area then,or

U-Boot will hang.

小心第一次对环境变量的存取发生在 UBOOT 初始化的过程中

?

Please note that even with NVRAM we still use a copy of the

environment in RAM: we could work on NVRAM directly,but we want to

keep settings there always unmodified except somebody uses "saveenv"

to save the current settings.

注意，即使是用非易失性 RAM 我们仍然用 RAM 中的环境变量，为的是保持环境变量的不更改，除非使用 "saveenv" 保存环境变量

?

?

- CFG_ENV_IS_IN_EEPROM:

?

?????? Use this if you have an EEPROM or similar serial access

?????? device and a driver for it.

?? EEPROM 或相应的串行访问设备时定义此项

?

?????? - CFG_ENV_OFFSET:

?????? - CFG_ENV_SIZE:

?

?????? ? These two #defines specify the offset and size of the

?????? ? environment area within the total memory of your EEPROM.

???? 指定环境变量在 EEPROM 中的偏移和大小

?

?????? - CFG_I2C_EEPROM_ADDR:

?????? ? If defined,specified the chip address of the EEPROM device.

?????? ? The default address is zero.

???? 定义 EERPOM 的器件地址，默认为 0

?

?????? - CFG_EEPROM_PAGE_WRITE_BITS:

?????? ? If defined,the number of bits used to address bytes in a

?????? ? single page in the EEPROM device.? A 64 byte page,for example

?????? ? would require six bits.

????? 用来声明 EEPROM 单页字节的位

?

?????? - CFG_EEPROM_PAGE_WRITE_DELAY_MS:

?????? ? If defined,the number of milliseconds to delay between

?????? ? page writes.????? The default is zero milliseconds.

???? 写页间隔，默认为 0 ，单位为毫秒

?

?????? - CFG_I2C_EEPROM_ADDR_LEN:

?????? ? The length in bytes of the EEPROM memory array address.? Note

?????? ? that this is NOT the chip address length!

???? EEPROM 储存阵列地址长度，非器件地址长度

?

?????? - CFG_I2C_EEPROM_ADDR_OVERFLOW:

?????? ? EEPROM chips that implement "address overflow" are ones

?????? ? like Catalyst 24WC04/08/16 which has 9/10/11 bits of

?????? ? address and the extra bits end up in the "chip address" bit

?????? ? slots. This makes a 24WC08 (1Kbyte) chip look like four 256

?????? ? byte chips.

?

?????? ? Note that we consider the length of the address field to

?????? ? still be one byte because the extra address bits are hidden

?????? ? in the chip address.

?

?????? - CFG_EEPROM_SIZE:

?????? ? The size in bytes of the EEPROM device.

????? EEPROM 大小，单位为字节

?

?

- CFG_ENV_IS_IN_DATAFLASH:

?

?????? Define this if you have a DataFlash memory device which you

?????? want to use for the environment.

?? ? 若想用数据 Flash 来储存环境变量就定义此项

?

?????? - CFG_ENV_OFFSET:

?????? - CFG_ENV_ADDR:

?????? - CFG_ENV_SIZE:

?

?????? ? These three #defines specify the offset and size of the

?????? ? environment area within the total memory of your DataFlash placed

?????? ? at the specified address.

?

- CFG_ENV_IS_IN_NAND:

?

?????? Define this if you have a NAND device which you want to use

?????? for the environment.

若想用 NAND Flash 来储存环境变量就定义此项

?

?????? - CFG_ENV_OFFSET:

?????? - CFG_ENV_SIZE:

?

?????? ? These two #defines specify the offset and size of the environment

?????? ? area within the first NAND device.

???? 指明环境变量在第一个 NAND 器件中的地址偏移和大小

?

?????? - CFG_ENV_OFFSET_REDUND

?

?????? ? This setting describes a second storage area of CFG_ENV_SIZE

?????? ? size used to hold a redundant copy of the environment data,

?????? ? so that there is a valid backup copy in case there is a

?????? ? power failure during a "saveenv" operation.

?

?????? Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned

?????? to a block boundary,and CFG_ENV_SIZE must be a multiple of

?????? the NAND devices block size.

CFG_ENV_SIZE 的大小必须是 NAND 器件块大小的倍数

?

- CFG_SPI_INIT_OFFSET

?

?????? Defines offset to the initial SPI buffer area in DPRAM. The

?????? area is used at an early stage (ROM part) if the environment

?????? is configured to reside in the SPI EEPROM: We need a 520 byte

?????? scratch DPRAM area. It is used between the two initialization

?????? calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems

?????? to be a good choice since it makes it far enough from the

?????? start of the data area as well as from the stack pointer.

?? 若环境变量存放在 SPI EEPROM 中时定义 DPRAM 中 SPI 缓存区的偏移

?

Please note that the environment is read-only until the monitor

has been relocated to RAM and a RAM copy of the environment has been

created; also,when using EEPROM you will have to use getenv_r()

until then to read environment variables.

在监视器被重新分配到 RAM 和环境变量在 RAM 中拷贝以前，环境变量为只读

?

The environment is protected by a CRC32 checksum. Before the monitor

is relocated into RAM,as a result of a bad CRC you will be working

with the compiled-in default environment - *silently*!!! [This is

necessary,because the first environment variable we need is the

"baudrate" setting for the console - if we have a bad CRC,we don't

have any device yet where we could complain.]

?

Note: once the monitor has been relocated,then it will complain if

the default environment is used; a new CRC is computed as soon as you

use the "saveenv" command to store a valid environment.

?

- CFG_FAULT_ECHO_LINK_DOWN:

????????????? Echo the inverted Ethernet link state to the fault LED.

?

????????????? Note: If this option is active,then CFG_FAULT_MII_ADDR

????????????? ????? also needs to be defined.

?

- CFG_FAULT_MII_ADDR:

????????????? MII address of the PHY to check for the Ethernet link state.

?

- CFG_64BIT_VSPRINTF:

????????????? Makes vsprintf (and all *printf functions) support printing

????????????? of 64bit values by using the L quantifier

?

- CFG_64BIT_STRTOUL:

????????????? Adds simple_strtoull that returns a 64bit value

?

Low Level (hardware related) configuration options:

底层配置选项（与硬件关联）

---------------------------------------------------

?

- CFG_CACHELINE_SIZE:

????????????? Cache Line Size of the CPU.

????? ?CPU Cache 大小

?

- CFG_DEFAULT_IMMR:

????????????? Default address of the IMMR after system reset.

?????? 系统重设后的 IMMR 默认地址

?

????????????? Needed on some 8260 systems (MPC8260ADS,PQ2FADS-ZU,

????????????? and RPXsuper) to be able to adjust the position of

????????????? the IMMR register after a reset.

?

-???????? Floppy Disk Support:

-???????? 软盘支持

????????????? CFG_FDC_DRIVE_NUMBER

?

????????????? the default drive number (default value 0)

?????? 默认驱动号，缺省为 0

?

????????????? CFG_ISA_IO_STRIDE

?

?????? ?????? defines the spacing between FDC chipset registers

????????????? (default value 1)

?????? FDC 芯片集寄存器间的空间

?

????????????? CFG_ISA_IO_OFFSET

?

????????????? defines the offset of register from address. It

????????????? depends on which part of the data bus is connected to

????????????? the FDC chipset. (default value 0)

?????? 寄存器的地址偏移，取决于 FDC 芯片集所连接的数据总线

?

????????????? If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and

????????????? CFG_FDC_DRIVE_NUMBER are undefined,they take their

????????????? default value.

?

????????????? if CFG_FDC_HW_INIT is defined,then the function

????????????? fdc_hw_init() is called at the beginning of the FDC

????????????? setup. fdc_hw_init() must be provided by the board

????????????? source code. It is used to make hardware dependant

????????????? initializations.

????? ? 若 CFG_FDC_HW_INIT 被定义，则板级源码中必须提供 fdc_hw_init() 的实现

?

-???????? CFG_IMMR:

?????? Physical address of the Internal Memory.

?????? 内存物理地址

?????? ?????? DO NOT CHANGE unless you know exactly what you're

????????????? doing! (11-4) [MPC8xx/82xx systems only]

????? ? 仅 MPC8xx/82xx

?

- CFG_INIT_RAM_ADDR:

?

????????????? Start address of memory area that can be used for

????????????? initial data and stack;

?????? 用来初始化数据和堆栈的内存起始地址

please note that this must be

????????????? writable memory that is working WITHOUT special

????????????? initialization,i. e. you CANNOT use normal RAM which

????????????? will become available only after programming the

????????????? memory controller and running certain initialization

????????????? sequences.

?????? 你不能用通常的 RAM ，因为他们只要在设置内存控制器

及初始化后才可用

?

????????????? U-Boot uses the following memory types:

?????? UBOOT 用一下几种内存

????????????? - MPC8xx and MPC8260: IMMR (internal memory of the CPU)

????????????? - MPC824X: data cache

????????????? - PPC4xx:? data cache

?

- CFG_GBL_DATA_OFFSET:

?

????????????? Offset of the initial data structure in the memory

????????????? area defined by CFG_INIT_RAM_ADDR.

? 内存中初始化数据结构的偏移地址

?Usually

????????????? CFG_GBL_DATA_OFFSET is chosen such that the initial

????????????? data is located at the end of the available space

?????? CFG_GBL_DATA_OFFSET 常选存在于可用空间末端的初始化数据

????????????? (sometimes written as (CFG_INIT_RAM_END -

????????????? CFG_INIT_DATA_SIZE),and the initial stack is just

????????????? below that area (growing from (CFG_INIT_RAM_ADDR +

????????????? CFG_GBL_DATA_OFFSET) downward.

?

?????? Note:

????????????? On the MPC824X (or other systems that use the data

????????????? cache for initial memory) the address chosen for

????????????? CFG_INIT_RAM_ADDR is basically arbitrary - it must

????????????? point to an otherwise UNUSED address space between

????????????? the top of RAM and the start of the PCI space.

?

- CFG_SIUMCR:?????? SIU Module Configuration (11-6)

?

- CFG_SYPCR:?? System Protection Control (11-9)

系统保护控制

?

- CFG_TBSCR:?? Time Base Status and Control (11-26)

?

- CFG_PISCR:??? Periodic Interrupt Status and Control (11-31)

?

- CFG_PLPRCR: PLL,Low-Power,and Reset Control Register (15-30)

PLL,低功耗，重启控制寄存器

?

- CFG_SCCR:???? System Clock and reset Control Register (15-27)

系统时钟和重设寄存器

?

- CFG_OR_TIMING_SDRAM:

????????????? SDRAM timing

SDRAM 时钟

?

- CFG_MAMR_PTA:

????????????? periodic timer for refresh

周期刷新时钟

?

- CFG_DER: Debug Event Register (37-47)

?

- FLASH_BASE0_PRELIM,FLASH_BASE1_PRELIM,CFG_REMAP_OR_AM,

? CFG_PRELIM_OR_AM,CFG_OR_TIMING_FLASH,CFG_OR0_REMAP,

? CFG_OR0_PRELIM,CFG_BR0_PRELIM,CFG_OR1_REMAP,CFG_OR1_PRELIM,

? CFG_BR1_PRELIM:

????????????? Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)

?

- SDRAM_BASE2_PRELIM,SDRAM_BASE3_PRELIM,SDRAM_MAX_SIZE,

? CFG_OR_TIMING_SDRAM,CFG_OR2_PRELIM,CFG_BR2_PRELIM,

? CFG_OR3_PRELIM,CFG_BR3_PRELIM:

????????????? Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)

?

- CFG_MAMR_PTA,CFG_MPTPR_2BK_4K,CFG_MPTPR_1BK_4K,CFG_MPTPR_2BK_8K,

? CFG_MPTPR_1BK_8K,CFG_MAMR_8COL,CFG_MAMR_9COL:

????????????? Machine Mode Register and Memory Periodic Timer

????????????? Prescaler definitions (SDRAM timing)

?

- CFG_I2C_UCODE_PATCH,CFG_I2C_DPMEM_OFFSET [0x1FC0]:

????????????? enable I2C microcode relocation patch (MPC8xx);

????????????? define relocation offset in DPRAM [DSP2]

?

- CFG_SMC_UCODE_PATCH,CFG_SMC_DPMEM_OFFSET [0x1FC0]:

????????????? enable SMC microcode relocation patch (MPC8xx);

????????????? define relocation offset in DPRAM [SMC1]

?

- CFG_SPI_UCODE_PATCH,CFG_SPI_DPMEM_OFFSET [0x1FC0]:

????????????? enable SPI microcode relocation patch (MPC8xx);

????????????? define relocation offset in DPRAM [SCC4]

?

- CFG_USE_OSCCLK:

????????????? Use OSCM clock mode on MBX8xx board. Be careful,

????????????? wrong setting might damage your board. Read

????????????? doc/README.MBX before setting this variable!

?

- CFG_CPM_POST_WORD_ADDR: (MPC8xx,MPC8260 only)

????????????? Offset of the bootmode word in DPRAM used by post

????????????? (Power On Self Tests). This definition overrides

????????????? #define'd default value in commproc.h resp.

????????????? cpm_8260.h.

?

- CFG_PCI_SLV_MEM_LOCAL,CFG_PCI_SLV_MEM_BUS,CFG_PICMR0_MASK_ATTRIB,

? CFG_PCI_MSTR0_LOCAL,CFG_PCIMSK0_MASK,CFG_PCI_MSTR1_LOCAL,

? CFG_PCIMSK1_MASK,CFG_PCI_MSTR_MEM_LOCAL,CFG_PCI_MSTR_MEM_BUS,

? CFG_CPU_PCI_MEM_START,CFG_PCI_MSTR_MEM_SIZE,CFG_POCMR0_MASK_ATTRIB,

? CFG_PCI_MSTR_MEMIO_LOCAL,CFG_PCI_MSTR_MEMIO_BUS,CPU_PCI_MEMIO_START,

? CFG_PCI_MSTR_MEMIO_SIZE,CFG_POCMR1_MASK_ATTRIB,CFG_PCI_MSTR_IO_LOCAL,

? CFG_PCI_MSTR_IO_BUS,CFG_CPU_PCI_IO_START,CFG_PCI_MSTR_IO_SIZE,

? CFG_POCMR2_MASK_ATTRIB: (MPC826x only)

????????????? Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.

?

- CONFIG_SPD_EEPROM

????????????? Get DDR timing information from an I2C EEPROM. Common

????????????? with pluggable memory modules such as SODIMMs

?

? SPD_EEPROM_ADDRESS

????????????? I2C address of the SPD EEPROM

?

- CFG_SPD_BUS_NUM

????????????? If SPD EEPROM is on an I2C bus other than the first

????????????? one,specify here. Note that the value must resolve

????????????? to something your driver can deal with.

?

- CFG_83XX_DDR_USES_CS0

????????????? Only for 83xx systems. If specified,then DDR should

????????????? be configured using CS0 and CS1 instead of CS2 and CS3.

?

- CFG_83XX_DDR_USES_CS0

????????????? Only for 83xx systems. If specified,then DDR should

????????????? be configured using CS0 and CS1 instead of CS2 and CS3.

?

- CONFIG_ETHER_ON_FEC[12]

????????????? Define to enable FEC[12] on a 8xx series processor.

?

- CONFIG_FEC[12]_PHY

????????????? Define to the hardcoded PHY address which corresponds

????????????? to the given FEC; i. e.

???????????????????? #define CONFIG_FEC1_PHY 4

????????????? means that the PHY with address 4 is connected to FEC1

?

????????????? When set to -1,means to probe for first available.

?

- CONFIG_FEC[12]_PHY_NORXERR

????????????? The PHY does not have a RXERR line (RMII only).

????????????? (so program the FEC to ignore it).

?

- CONFIG_RMII

????????????? Enable RMII mode for all FECs.

????????????? Note that this is a global option,we can't

????????????? have one FEC in standard MII mode and another in RMII mode.

?

- CONFIG_CRC32_VERIFY

????????????? Add a verify option to the crc32 command.

????????????? The syntax is:

?

????????????? => crc32 -v <address> <count> <crc32>

?

????????????? Where address/count indicate a memory area

????????????? and crc32 is the correct crc32 which the

????????????? area should have.

?

- CONFIG_LOOPW

????????????? Add the "loopw" memory command. This only takes effect if

????????????? the memory commands are activated globally (CONFIG_CMD_MEM).

?

- CONFIG_MX_CYCLIC

????????????? Add the "mdc" and "mwc" memory commands. These are cyclic

????????????? "md/mw" commands.

????????????? Examples:

?

????????????? => mdc.b 10 4 500

????????????? This command will print 4 bytes (10,11,12,13) each 500 ms.

?

????????????? => mwc.l 100 12345678 10

????????????? This command will write 12345678 to address 100 all 10 ms.

?

????????????? This only takes effect if the memory commands are activated

????????????? globally (CONFIG_CMD_MEM).

?

- CONFIG_SKIP_LOWLEVEL_INIT

- CONFIG_SKIP_RELOCATE_UBOOT

?

????????????? [ARM only] If these variables are defined,then

????????????? certain low level initializations (like setting up

????????????? the memory controller) are omitted and/or U-Boot does

????????????? not relocate itself into RAM.

????? ? 【仅对 ARM 】如果这些变量定义，则忽略一些底层初始化，

UBOOT 不重加载自己到 RAM

????????????? Normally these variables MUST NOT be defined. The

????????????? only exception is when U-Boot is loaded (to RAM) by

????????????? some other boot loader or by a debugger which

????????????? performs these initializations itself.

?????? 通常这些变量不要被定义，除非有 UBOOT 由

其他 BOOTLOADER 加载到 RAM ，并初始化

?

?

第二步

Building the Software:

编译软件

======================

?

Building U-Boot has been tested in several native build environments

and in many different cross environments. Of course we cannot support

all possibly existing versions of cross development tools in all

(potentially obsolete) versions. In case of tool chain problems we

recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)

which is extensively used to build and test U-Boot.

UBOOT 已经在很多编译环境下编译成功，但我们不保证所有的交叉编译工具都能使用，如果发生问题，请用 ELDK 编译工具编译和测试 UBOOT

http://www.denx.de/wiki/DULG/ELDK

?

If you are not using a native environment,it is assumed that you

have GNU cross compiling tools available in your path.

若你不用本地环境，我们假设在你的路径下已经有了 GNU 的交叉编译工具。

In this case,

you must set the environment variable CROSS_COMPILE in your shell.

这时你必须设置环境变量 CROSS_COMPILE

Note that no changes to the Makefile or any other source files are

necessary. For example using the ELDK on a 4xx CPU,please enter:

?

?????? $ CROSS_COMPILE=ppc_4xx-

?????? $ export CROSS_COMPILE

?

U-Boot is intended to be simple to build. After installing the

sources you must configure U-Boot for one specific board type. This

is done by typing:

UBOOT 目标是容易编译。安装完源码后你必须为特定的板配置 UBOOT 。

如下：

?

?????? make NAME_config

?

where "NAME_config" is the name of one of the existing configu-

rations; see the main Makefile for supported names.

"NAME_config" 是应经存在的配置，查看主 Makefile 或得支持的名字

?

Note: for some board special configuration names may exist; check if

????? additional information is available from the board vendor; for

????? instance,the TQM823L systems are available without (standard)

????? or with LCD support.

有一些特殊配置名已经存在，检查板供应商的附加信息是否已经存在

如 TQM823L 系统有带 LCD 和不带之分，都已存在配置名

You can select such additional "features"

????? when choosing the configuration,i. e.

?

????? make TQM823L_config

?????? - will configure for a plain TQM823L,i. e. no LCD support

?

????? make TQM823L_LCD_config

?????? - will configure for a TQM823L with U-Boot console on LCD

????? 这两个配置命令都可以使用，但是前一个不配置 LCD 控制台

?

????? etc.

?

?

Finally,type "make all",and you should get some working U-Boot

images ready for download to / installation on your system:

最后执行 "make all" ， 你将得到一些 UBOOT 映像，用来下载或初始化你的系统。

?

- "u-boot.bin" is a raw binary image

"u-boot.bin" 原始二进制映像

- "u-boot" is an image in ELF binary format

"u-boot"ELF 二进制格式映像

-???????? "u-boot.srec" is in Motorola S-Record format

"u-boot.srec" 摩托罗拉 S-Record 格式映像

?

By default the build is performed locally and the objects are saved

in the source directory. One of the two methods can be used to change

this behavior and build U-Boot to some external directory:

默认情况下，编译在本地执行，目标文件保存到原目录，若想改变编译目录可用以下方法

?

1.????? Add O= to the make command line invocations:

在 make 命令行增加 O 标记

?

?????? make O=/tmp/build distclean

?????? make O=/tmp/build NAME_config

?????? make O=/tmp/build all

?

2.????? Set environment variable BUILD_DIR to point to the desired location:

设置环境变量指向希望的目录

?

?????? export BUILD_DIR=/tmp/build

?????? make distclean

?????? make NAME_config

?????? make all

?

Note that the command line "O=" setting overrides the BUILD_DIR environment

variable.

第一方法的优先级高于第二方法

?

?

Please be aware that the Makefiles assume you are using GNU make,so

for instance on NetBSD you might need to use "gmake" instead of

native "make".

Makefiles 假定你使用 GNU 的 make ，比如在 NetBSD 上你应该用 gmake

?

?

If the system board that you have is not listed,then you will need

to port U-Boot to your hardware platform.

若你的系统板没有列出来，那你将移植 UBOOT 到你的硬件平台上

To do this,follow these steps:

遵照一下步骤进行移植：

?

1.? Add a new configuration option for your board to the toplevel

??? "Makefile" and to the "MAKEALL" script,using the existing

entries as examples.

依照已存在的入口在顶层 "Makefile" 和 "MAKEALL" 脚本中

增加你板子的配置选项

Note that here and at many other places

??? boards and other names are listed in alphabetical sort order. Please

keep this order.

板和其他名字都是按字母排序的，请遵照这种顺序

2.? Create a new directory to hold your board specific code. Add any

??? files you need. In your board directory,you will need at least

the "Makefile",a "<board>.c","flash.c" and "u-boot.lds".

创建一个新的目录来保存你板子的代码，增加你需要的文件。

在你的目录里至少需要 "Makefile" 、 "<board>.c" 、 "flash.c" 、 "u-boot.lds"

3.? Create a new configuration file "include/configs/<board>.h" for

your board

为你的板子创建一个新的配置文件 "include/configs/<board>.h"

3.? If you're porting U-Boot to a new CPU,then also create a new

directory to hold your CPU specific code. Add any files you need.

若你移植 UBOOT 到一个新的 CPU ，你还需建立一个新的目录

来保存你 CPU 的代码，和文件

4.? Run "make <board>_config" with your new name.

??? 用你的新名运行 "make <board>_config" ，

5.? Type "make",and you should get a working "u-boot.srec" file

to be installed on your target system.

得到映像文件

6.? Debug and solve any problems that might arise.

[Of course,this last step is much harder than it sounds.]

调试

?

?

Testing of U-Boot Modifications,Ports to New Hardware,etc.:

测试 UBOOT 的更改，移植到新的硬件

=============================================================

?

If you have modified U-Boot sources (for instance added a new board

or support for new devices,a new CPU,etc.) you are expected to

provide feedback to the other developers. The feedback normally takes

the form of a "patch",i. e. a context diff against a certain (latest

official or latest in the git repository) version of U-Boot sources.

如果你更改了 UBOOT 源码，并希望反馈给其他的开发者，

你可以以补丁的形式分发

?

But before you submit such a patch,please verify that your modifi-

cation did not break existing code. At least make sure that *ALL* of

the supported boards compile WITHOUT ANY compiler warnings. To do so,

just run the "MAKEALL" script,which will configure and build U-Boot

for ALL supported system.

为确保你的更改没有错误，请执行 "MAKEALL" 脚本配置所有支持的系统

Be warned,this will take a while. You can

select which (cross) compiler to use by passing a `CROSS_COMPILE'

environment variable to the script,i. e. to use the ELDK cross tools

you can type

?

?????? CROSS_COMPILE=ppc_8xx- MAKEALL

?

or to build on a native PowerPC system you can type

?

?????? CROSS_COMPILE=' ' MAKEALL

?

When using the MAKEALL script,the default behaviour is to build

U-Boot in the source directory. This location can be changed by

setting the BUILD_DIR environment variable. Also,for each target

built,the MAKEALL script saves two log files (<target>.ERR and

<target>.MAKEALL) in the <source dir>/LOG directory. This default

location can be changed by setting the MAKEALL_LOGDIR environment

variable.

当执行 MAKEALL 脚本默认在 UBOOT 源目录生成日志文件

<target>.ERR 和 <target>.MAKEALL ，若要更改路径则需设置

MAKEALL_LOGDIR 环境变量

For example:

?

?????? export BUILD_DIR=/tmp/build

?????? export MAKEALL_LOGDIR=/tmp/log

?????? CROSS_COMPILE=ppc_8xx- MAKEALL

?

With the above settings build objects are saved in the /tmp/build,

log files are saved in the /tmp/log and the source tree remains clean

during the whole build process.

这样可以保持源码目录树的清洁

?

?

See also "U-Boot Porting Guide" below.

继续查看下面的 "U-Boot Porting Guide"UBOOT 移植手册

?

?

Monitor Commands - Overview:

监控命令概述

============================

?

go ?? - start application at address 'addr'

???? ? 运行在地址 'addr' 的程序

run ? - run commands in an environment variable

????? 执行环境变量中的命令

bootm ??? - boot application image from memory

????? 从内存启动应用映像

bootp ???? - boot image via network using BootP/TFTP protocol

用 BootP/TFTP 协议通过网络启动映像

tftpboot - boot image via network using TFTP protocol

用 TFTP 协议通过网络启动映像

?

?????? ?????? and env variables "ipaddr" and "serverip"

?????? ?????? (and eventually "gatewayip")

rarpboot - boot image via network using RARP/TFTP protocol

???????? 用 RARP/TFTP 协议通过网络启动映像

?

diskboot - boot from IDE devicebootd?? - boot default,i.e.,run 'bootcmd'

????? 从 IDE 设备启动

loads ????? - load S-Record file over serial line

????? 通过串口加载 S-Record 文件

loadb ????? - load binary file over serial line (kermit mode)

????? 通过串口加载二进制文件

md ? - memory display

????? 显示储存器

mm ? - memory modify (auto-incrementing)

???? ? 更改储存器（自动增量）

nm ?? - memory modify (constant address)

???? ? 更改储存器（静态地址）

mw ? - memory write (fill)

????? 写储存器

cp ?? - memory copy

????? 拷贝储存器

cmp - memory compare

????? 比较储存器

crc32 ???? - checksum calculation

????? 校验和计算

imd ? - i2c memory display

?????? 显示 i2c 储存器

imm - i2c memory modify (auto-incrementing)

????????????? 更改 i2c 储存器（自动增量）

inm ? - i2c memory modify (constant address)

????????????? 更改 i2c 储存器（静态地址）

imw - i2c memory write (fill)

????????????? 写 i2c 储存器

icrc32 ???? - i2c checksum calculation

?????? i2c 校验和计算

iprobe ??? - probe to discover valid I2C chip addresses

?????? 查找存在的 I2C 器件地址

iloop ?????? - infinite loop on address range

????????????? 在地址范围内无限循环

isdram ??? - print SDRAM configuration information

?????? 显示 SDRAM 配置信息

sspi - SPI utility commands

????????????? SPI 命令

base ?????? - print or set address offset

????????????? 显示或设置地址偏移

printenv - print environment variables

????????????? 显示环境变量

setenv ???? - set environment variables

????????????? 设置环境变量

????????????? 不带参数的 setenv 可删除环境变量数据

saveenv - save environment variables to persistent storage

????????????? 永久保存环境变量

protect - enable or disable FLASH write protection

????????????? 允许或禁止 FLASH 写保护

erase ????? - erase FLASH memory

????????????? 擦除 FLASH

flinfo ?????? - print FLASH memory information

????????????? 显示 FLASH 信息

bdinfo ???? - print Board Info structure

????????????? 显示板信息

iminfo ???? - print header information for application image

????????????? 显示镜像的开头信息

coninfo - print console devices and informations

????????????? 显示控制台设备及其信息

ide ?? - IDE sub-system

????????????? IDE 子系统

loop ?????? - infinite loop on address range

????????????? 在地址范围内无限循环

loopw ???? - infinite write loop on address range

????????????? 在地址范围内无限写循环

mtest ????? - simple RAM test

????????????? 简单 RAM 测试

icache ???? - enable or disable instruction cache

????????????? 使能或禁止指令 cache

dcache ?? - enable or disable data cache

????????????? 使能或禁止数据 cache

reset ?????? - Perform RESET of the CPU

????????????? 执行 CPU 重设

echo ?????? - echo args to console

????????????? 回显参数

version - print monitor version

????????????? 显示版本信息

help - print online help

????????????? 显示在线帮助

? ???? - alias for 'help'

????????????? 显示帮助

?

?

Monitor Commands - Detailed Description:

监控命令 — 详细说明

========================================

?

TODO.

?

For now: just type "help <command>".

?

?

Environment Variables:

环境变量

======================

?

U-Boot supports user configuration using Environment Variables which

can be made persistent by saving to Flash memory.

?

Environment Variables are set using "setenv",printed using

"printenv",and saved to Flash using "saveenv". Using "setenv"

without a value can be used to delete a variable from the

environment. As long as you don't save the environment you are

working with an in-memory copy. In case the Flash area containing the

environment is erased by accident,a default environment is provided.

?

Some configuration options can be set using Environment Variables:

下面这些配置选项课通过环境变量来设置

?

? baudrate??? - see CONFIG_BAUDRATE

?

? bootdelay? - see CONFIG_BOOTDELAY

?

? bootcmd??? - see CONFIG_BOOTCOMMAND

?

? bootargs??? - Boot arguments when booting an RTOS image

?

? bootfile????? - Name of the image to load with TFTP

?

? bootm_low?????? - Memory range available for image processing in the bootm

????????????? ? command can be restricted. This variable is given as

????????????? ? a hexadecimal number and defines lowest address allowed

????????????? ? for use by the bootm command.

定义了 bootm 命令的最低地址

See also "bootm_size"

????????????? ? environment variable. Address defined by "bootm_low" is

????????????? ? also the base of the initial memory mapping for the Linux

????????????? ? kernel -- see the description of CFG_BOOTMAPSZ.

???????????????????? 也是 Linux 映像初始化内存映射的基址

?

??bootm_size?????? - Memory range available for image processing in the bootm

????????????? ? command can be restricted. This variable is given as

????????????? ? a hexadecimal number and defines the size of the region

????????????? ? allowed for use by the bootm command.

定义了 bootm 命令的范围

??See also "bootm_low"

????????????? ? environment variable.

?

? autoload??? - if set to "no" (any string beginning with 'n'),

????????????? ? "bootp" will just load perform a lookup of the

????????????? ? configuration from the BOOTP server,but not try to

????????????? ? load any image using TFTP

????????????????? 若设置为 "no" （任何以 'n' 开头的字符串）， "bootp" 将只在 BOOTP 服务器查找映像，但不下载

?

? autoscript? - if set to "yes" commands like "loadb","loady",

????????????? ? "bootp","tftpb","rarpboot" and "nfs" will attempt

????????????? ? to automatically run script images (by internally

????????????? ? calling "autoscript").

????????????? ?? 若设置为 "yes" 则 "loadb","bootp",

"rarpboot" and "nfs" 将尝试自动运行脚本映像

?

? autoscript_uname - if script image is in a format (FIT) this

????????????? ???? variable is used to get script subimage unit name.

?

? autostart??? - if set to "yes",an image loaded using the "bootp",

????????????? ? "rarpboot","tftpboot" or "diskboot" commands will

????????????? ? be automatically started (by internally calling

????????????? ? "bootm")

???????????????????? 若设置为 "yes" 则通过 "bootp","rarpboot","tftpboot" or "diskboot"

????????????? ?? 命令下载的映像将自动开始

?

????????????? ? If set to "no",a standalone image passed to the

????????????? ? "bootm" command will be copied to the load address

????????????? ? (and eventually uncompressed),but NOT be started.

????????????? ? This can be used to load and uncompress arbitrary

????????????? ? data.

?

? i2cfast?????? - (PPC405GP|PPC405EP only)

????????????? ? if set to 'y' configures Linux I2C driver for fast

????????????? ? mode (400kHZ). This environment variable is used in

????????????? ? initialization code. So,for changes to be effective

????????????? ? it must be saved and board must be reset.

?

? initrd_high? - restrict positioning of initrd images:

????????????? ? 限制 initrd 镜像的位置

????????????? ? If this variable is not set,initrd images will be

????????????? ? copied to the highest possible address in RAM;

??????? ? 不设置的话就会放到 RAM 的最高地址

This is usually what you want since it allows for

????????????? ? maximum initrd size. If for some reason you want to

????????????? ? make sure that the initrd image is loaded below the

????????????? ? CFG_BOOTMAPSZ limit,you can set this environment

????????????? ? variable to a value of "no" or "off" or "0".

????????????? ? Alternatively,you can set it to a maximum upper

????????????? ? address to use (U-Boot will still check that it

????????????? ? does not overwrite the U-Boot stack and data).

?

????????????? ? For instance,when you have a system with 16 MB

????????????? ? RAM,and want to reserve 4 MB from use by Linux,

????????????? ? you can do this by adding "mem=12M" to the value of

????????????? ? the "bootargs" variable. However,now you must make

????????????? ? sure that the initrd image is placed in the first

????????????? ? 12 MB as well - this can be done with

???????? 比如你有 16M RAM ，你想保留 4M ，则把 "mem=12M" 增加到

"bootargs" 环境变量，现在你必须保证 initrd 镜像被放置在开头

12M 的空间，你可以运行：

?

????????????? ? setenv initrd_high 00c00000

?

?

????????????? ? If you set initrd_high to 0xFFFFFFFF,this is an

????????????? ? indication to U-Boot that all addresses are legal

????????????? ? for the Linux kernel,including addresses in flash

????????????? ? memory. In this case U-Boot will NOT COPY the

????????????? ? ramdisk at all. This may be useful to reduce the

????????????? ? boot time on your system,but requires that this

????????????? ? feature is supported by your Linux kernel.

?

? ipaddr?????? - IP address; needed for tftpboot command

????????? ?tftpboot 命令会用到的 IP 地址

?

? loadaddr??? - Default load address for commands like "bootp","tftpboot","loadb" or "diskboot"

"bootp","loadb" or "diskboot"

? 命令的默认装载地址

?

?

? loads_echo?????? - see CONFIG_LOADS_ECHO

?

? serverip???? - TFTP server IP address; needed for tftpboot command

???????? TFTP 服务的 IP 地址

?

? bootretry?? - see CONFIG_BOOT_RETRY_TIME

?

? bootdelaykey??? - see CONFIG_AUTOBOOT_DELAY_STR

?

? bootstopkey???? - see CONFIG_AUTOBOOT_STOP_STR

?

? ethprime??? - When CONFIG_NET_MULTI is enabled controls which

????????????? ? interface is used first.

?

? ethact - When CONFIG_NET_MULTI is enabled controls which

????????????? ? interface is currently active.

???????? 激活哪个网络接口

For example you can do the following

?

????????????? ? => setenv ethact FEC ETHERNET

????????????? ? => ping 192.168.0.1 # traffic sent on FEC ETHERNET

????????????? ? => setenv ethact SCC ETHERNET

????????????? ? => ping 10.0.0.1 # traffic sent on SCC ETHERNET

?

? ethrotate??? - When set to "no" U-Boot does not go through all

????????????? ? available network interfaces.

?????? ???? 若设置为 "no"UBOOT 将不会遍历所有的可用网络接口

????????????? ? It just stays at the currently selected interface.

?

?? netretry??? - When set to "no" each network operation will

????????????? ? either succeed or fail without retrying.

??????? ? 网络操作不重试

????????????? ? When set to "once" the network operation will

????????????? ? fail when all the available network interfaces

????????????? ? are tried once without success.

????????????? ? Useful on scripts which control the retry operation

????????????? ? themselves.

?

? npe_ucode?????? - see CONFIG_IXP4XX_NPE_EXT_UCOD

????????????? ? if set load address for the NPE microcode

?

? tftpsrcport - If this is set,the value is used for TFTP's

????????????? ? UDP source port.

??????????? TFTP UDP 源端口

?

? tftpdstport - If this is set,the value is used for TFTP's UDP

????????????? ? destination port instead of the Well Know Port 69.

??????????? TFTP UDP 源端口目的端口

?

?? vlan???????? - When set to a value < 4095 the traffic over

????????????? ? Ethernet is encapsulated/received over 802.1q

????????????? ? VLAN tagged frames.

?

The following environment variables may be used and automatically

updated by the network boot commands ("bootp" and "rarpboot"),

depending the information provided by your boot server:

?

? bootfile????? - see above

? dnsip???????? - IP address of your Domain Name Server

? dnsip2?????? - IP address of your secondary Domain Name Server

? gatewayip? - IP address of the Gateway (Router) to use

? hostname?? - Target hostname

? ipaddr?????? - see above

? netmask???? - Subnet Mask

? rootpath??? - Pathname of the root filesystem on the NFS server

? serverip???? - see above

?

?

There are two special Environment Variables:

?

? serial#?????? - contains hardware identification information such

????????????? ? as type string and/or serial number

? ethaddr????? - Ethernet address

?

These variables can be set only once (usually during manufacturing of

the board). U-Boot refuses to delete or overwrite these variables

once they have been set once.

?

?

Further special Environment Variables:

?

? ver??????????? - Contains the U-Boot version string as printed

????????????? ? with the "version" command. This variable is

????????????? ? readonly (see CONFIG_VERSION_VARIABLE).

?

?

Please note that changes to some configuration parameters may take

only effect after the next boot (yes,that's just like Windoze :-).

?

?

Command Line Parsing:

命令行分析

=====================

?

There are two different command line parsers available with U-Boot:

UBOOT 支持两种不同的命令行

the old "simple" one,and the much more powerful "hush" shell:

?

Old,simple command line parser:

老而简单的

--------------------------------

?

- supports environment variables (through setenv / saveenv commands)

- several commands on one line,separated by ';'

同一行的多个命令用分号隔开

- variable substitution using "... ${name} ..." syntax

变量替换语法 "... ${name} ..."

-???????? special characters ('$',';') can be escaped by prefixing with '/',

特殊字符前加 '/'

? for example:

?????? setenv bootcmd bootm /${address}

- You can also escape text by enclosing in single apostrophes,for example:

?????? setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'

?

Hush shell:

Hush shell

-----------

?

-???????? similar to Bourne shell,with control structures like

-???????? 同 Bourne shell 类似

??if...then...else...fi,for...do...done; while...do...done,

? until...do...done,...

- supports environment ("global") variables (through setenv / saveenv

? commands) and local shell variables (through standard shell syntax

? "name=value"); only environment variables can be used with "run"

? Command

? 支持环境变量和本地 shell 变量，只有环境变量才可用 "run" 命令

?

General rules:

--------------

?

(1) If a command line (or an environment variable executed by a "run"

??? command) contains several commands separated by semicolon,and

??? one of these commands fails,then the remaining commands will be

??? executed anyway.

?

(2) If you execute several variables with one call to run (i. e.

??? calling run with a list of variables as arguments),any failing

??? command will cause "run" to terminate,i. e. the remaining

??? variables are not executed.

?

Note for Redundant Ethernet Interfaces:

关于以太网接口

=======================================

?

Some boards come with redundant Ethernet interfaces; U-Boot supports

such configurations and is capable of automatic selection of a

"working" interface when needed. MAC assignment works as follows:

?

Network interfaces are numbered eth0,eth1,eth2,... Corresponding

MAC addresses can be stored in the environment as "ethaddr" (=>eth0),

"eth1addr" (=>eth1),"eth2addr",...

支持多网卡

?

If the network interface stores some valid MAC address (for instance

in SROM),this is used as default address if there is NO correspon-

ding setting in the environment; if the corresponding environment

variable is set,this overrides the settings in the card; that means:

?

o If the SROM has a valid MAC address,and there is no address in the

? environment,the SROM's address is used.

?

o If there is no valid address in the SROM,and a definition in the

? environment exists,then the value from the environment variable is

? used.

?

o If both the SROM and the environment contain a MAC address,and

? both addresses are the same,this MAC address is used.

?

o If both the SROM and the environment contain a MAC address,and the

? addresses differ,the value from the environment is used and a

? warning is printed.

? 若网卡 SROM 中 MAC 地址和环境变量中的 MAC 地址不一样

则默认使用环境变量

?

o If neither SROM nor the environment contain a MAC address,an error

? is raised.

?

?

Image Formats:

映像格式

==============

?

U-Boot is capable of booting (and performing other auxiliary operations on)

images in two formats:

?

New uImage format (FIT)

新 uImage 格式（ FIT ）

-----------------------

?

Flexible and powerful format based on Flattened Image Tree -- FIT (similar

to Flattened Device Tree). It allows the use of images with multiple

components (several kernels,ramdisks,etc.),with contents protected by

SHA1,MD5 or CRC32. More details are found in the doc/uImage.FIT directory.

更多细节请阅读 doc/uImage.FIT

?

?

Old uImage format

老 uImage 格式

-----------------

?

Old image format is based on binary files which can be basically anything,

preceded by a special header; see the definitions in include/image.h for

details; basically,the header defines the following image properties:

?

* Target Operating System (Provisions for OpenBSD,NetBSD,FreeBSD,

? 4.4BSD,Linux,SVR4,Esix,Solaris,Irix,SCO,Dell,NCR,

? LynxOS,pSOS,QNX,RTEMS,ARTOS;

? Currently supported: Linux,ARTOS,LynxOS).

* Target CPU Architecture (Provisions for Alpha,ARM,AVR32,Intel x86,

? IA64,MIPS,NIOS,PowerPC,IBM S390,SuperH,Sparc,Sparc 64 Bit;

? Currently supported: ARM,PowerPC).

* Compression Type (uncompressed,gzip,bzip2)

* Load Address

* Entry Point

* Image Name

* Image Timestamp

?

The header is marked by a special Magic Number,and both the header

and the data portions of the image are secured against corruption by

CRC32 checksums.

?

?

Linux Support:

==============

?

Although U-Boot should support any OS or standalone application

easily,the main focus has always been on Linux during the design of

U-Boot.

?

U-Boot includes many features that so far have been part of some

special "boot loader" code within the Linux kernel. Also,any

"initrd" images to be used are no longer part of one big Linux image;

instead,kernel and "initrd" are separate images. This implementation

serves several purposes:

?

- the same features can be used for other OS or standalone

? applications (for instance: using compressed images to reduce the

? Flash memory footprint)

?

- it becomes much easier to port new Linux kernel versions because

? lots of low-level,hardware dependent stuff are done by U-Boot

?

- the same Linux kernel image can now be used with different "initrd"

? images; of course this also means that different kernel images can

? be run with the same "initrd". This makes testing easier (you don't

? have to build a new "zImage.initrd" Linux image when you just

? change a file in your "initrd"). Also,a field-upgrade of the

? software is easier now.

?

?

Linux HOWTO:

怎么移植 Linux

============

?

Porting Linux to U-Boot based systems:

---------------------------------------

?

U-Boot cannot save you from doing all the necessary modifications to

configure the Linux device drivers for use with your target hardware

(no,we don't intend to provide a full virtual machine interface to

Linux :-).

?

But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).

?

Just make sure your machine specific header file (for instance

include/asm-ppc/tqm8xx.h) includes the same definition of the Board

Information structure as we define in include/u-boot.h,and make

sure that your definition of IMAP_ADDR uses the same value as your

U-Boot configuration in CFG_IMMR.

确保你机器的特殊头文件包含板卡的定义与在 include/u-boot.h 中的定义相同，

确保 IMAP_ADDR 定义和 UBOOT 中的 CFG_IMMR 定义相同

?

?

?

Configuring the Linux kernel:

配置 Linux 内核

-----------------------------

?

No specific requirements for U-Boot. Make sure you have some root

device (initial ramdisk,NFS) for your target system.

?

?

Building a Linux Image:

编译 Linux 内核

-----------------------

?

With U-Boot,"normal" build targets like "zImage" or "bzImage" are

not used. If you use recent kernel source,a new build target

"uImage" will exist which automatically builds an image usable by

U-Boot. Most older kernels also have support for a "pImage" target,

which was introduced for our predecessor project PPCBoot and uses a

100% compatible format.

编译成新的 "uImage" 目标格式

?

Example:

?

?????? make TQM850L_config

?????? make oldconfig

?????? make dep

?????? make uImage

?

The "uImage" build target uses a special tool (in 'tools/mkimage') to

encapsulate a compressed Linux kernel image with header??? information,

CRC32 checksum etc. for use with U-Boot. This is what we are doing:

?

* build a standard "vmlinux" kernel image (in ELF binary format):

编译成标准 "vmlinux" 内核镜像

?

convert the kernel into a raw binary image:

转换为原始二进制映像

?

?????? ${CROSS_COMPILE}-objcopy -O binary /

??????????????????????????? ?-R .note -R .comment /

??????????????????????????? ?-S vmlinux linux.bin

?

compress the binary image:

压缩映像

?

?????? gzip -9 linux.bin

?

package compressed binary image for U-Boot:

打包

?

?????? mkimage -A ppc -O linux -T kernel -C gzip /

????????????? -a 0 -e 0 -n "Linux Kernel Image" /

????????????? -d linux.bin.gz uImage

?

?

The "mkimage" tool can also be used to create ramdisk images for use

with U-Boot,either separated from the Linux kernel image,or

combined into one file. "mkimage" encapsulates the images with a 64

byte header containing information about target architecture,

operating system,image type,compression method,entry points,time

stamp,CRC32 checksums,etc.

?

"mkimage" can be called in two ways: to verify existing images and

print the header information,or to build new images.

"mkimage" 有两种调用方法

?

In the first form (with "-l" option) mkimage lists the information

contained in the header of an existing U-Boot image; this includes

checksum verification:

?

1 、打印头信息

?????? tools/mkimage -l image

?????? ? -l ==> list image header information

?

The second form (with "-d" option) is used to build a U-Boot image

from a "data file" which is used as image payload:

2 、把数据文件压缩成映像

?????? tools/mkimage -A arch -O os -T type -C comp -a addr -e ep /

????????????? ????? -n name -d data_file image

?????? ? -A ==> set architecture to 'arch'

?????? ? -O ==> set operating system to 'os'

?????? ? -T ==> set image type to 'type'

?????? ? -C ==> set compression type 'comp'

?????? ? -a ==> set load address to 'addr' (hex)

?????? ? -e ==> set entry point to 'ep' (hex)

?????? ? -n ==> set image name to 'name'

?????? ? -d ==> use image data from 'datafile'

?

Right now,all Linux kernels for PowerPC systems use the same load

address (0x00000000),but the entry point address depends on the

kernel version:

?

- 2.2.x kernels have the entry point at 0x0000000C,

- 2.3.x and later kernels have the entry point at 0x00000000.

?

So a typical call to build a U-Boot image would read:

?

?????? -> tools/mkimage -n '2.4.4 kernel for TQM850L' /

?????? > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 /

?????? > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz /

?????? > examples/uImage.TQM850L

?????? Image Name:?? 2.4.4 kernel for TQM850L

?????? Created:????? Wed Jul 19 02:34:59 2000

?????? Image Type:?? PowerPC Linux Kernel Image (gzip compressed)

?????? Data Size:??? 335725 Bytes = 327.86 kB = 0.32 MB

?????? Load Address: 0x00000000

?????? Entry Point:? 0x00000000

?

To verify the contents of the image (or check for corruption):

?

?????? -> tools/mkimage -l examples/uImage.TQM850L

?????? Image Name:?? 2.4.4 kernel for TQM850L

?????? Created:????? Wed Jul 19 02:34:59 2000

?????? Image Type:?? PowerPC Linux Kernel Image (gzip compressed)

?????? Data Size:??? 335725 Bytes = 327.86 kB = 0.32 MB

?????? Load Address: 0x00000000

?????? Entry Point:? 0x00000000

?

NOTE: for embedded systems where boot time is critical you can trade

speed for memory and install an UNCOMPRESSED image instead: this

needs more space in Flash,but boots much faster since it does not

need to be uncompressed:

?

?????? -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz

?????? -> tools/mkimage -n '2.4.4 kernel for TQM850L' /

?????? > -A ppc -O linux -T kernel -C none -a 0 -e 0 /

?????? > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux /

?????? > examples/uImage.TQM850L-uncompressed

?????? Image Name:?? 2.4.4 kernel for TQM850L

?????? Created:????? Wed Jul 19 02:34:59 2000

?????? Image Type:?? PowerPC Linux Kernel Image (uncompressed)

?????? Data Size:??? 792160 Bytes = 773.59 kB = 0.76 MB

?????? Load Address: 0x00000000

?????? Entry Point:? 0x00000000

?

?

Similar you can build U-Boot images from a 'ramdisk.image.gz' file

when your kernel is intended to use an initial ramdisk:

?

?????? -> tools/mkimage -n 'Simple Ramdisk Image' /

?????? > -A ppc -O linux -T ramdisk -C gzip /

?????? > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd

?????? Image Name:?? Simple Ramdisk Image

?????? Created:????? Wed Jan 12 14:01:50 2000

?????? Image Type:?? PowerPC Linux RAMDisk Image (gzip compressed)

?????? Data Size:??? 566530 Bytes = 553.25 kB = 0.54 MB

?????? Load Address: 0x00000000

?????? Entry Point:? 0x00000000

?

?

Installing a Linux Image:

-------------------------

?

To downloading a U-Boot image over the serial (console) interface,

you must convert the image to S-Record format:

要从串口下载 UBOOT 映像，就要将其转换为 S-Record 格式

?

?????? objcopy -I binary -O srec examples/image examples/image.srec

?

The 'objcopy' does not understand the information in the U-Boot

image header,so the resulting S-Record file will be relative to

address 0x00000000. To load it to a given address,you need to

specify the target address as 'offset' parameter with the 'loads'

command.

?

Example: install the image to address 0x40100000 (which on the

TQM8xxL is in the first Flash bank):

?

?????? => erase 40100000 401FFFFF

?

?????? .......... done

?????? Erased 8 sectors

?

?????? => loads 40100000

?????? ## Ready for S-Record download ...

?????? ~>examples/image.srec

?????? 1 2 3 4 5 6 7 8 9 10 11 12 13 ...

?????? ...

?????? 15989 15990 15991 15992

?????? [file transfer complete]

?????? [connected]

?????? ## Start Addr = 0x00000000

?

?

You can check the success of the download using the 'iminfo' command;

this includes a checksum verification so you can be sure no data

corruption happened:

?

?????? => imi 40100000

?

?????? ## Checking Image at 40100000 ...

?????? ?? Image Name:? 2.2.13 for initrd on TQM850L

?????? ?? Image Type:??? PowerPC Linux Kernel Image (gzip compressed)

?????? ?? Data Size:?????? 335725 Bytes = 327 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 0000000c

?????? ?? Verifying Checksum ... OK

?

?

Boot Linux:

启动 Linux

-----------

?

The "bootm" command is used to boot an application that is stored in

memory (RAM or Flash). In case of a Linux kernel image,the contents

of the "bootargs" environment variable is passed to the kernel as

parameters.

"bootargs" 环境变量将作为参数传递到内核

You can check and modify this variable using the

"printenv" and "setenv" commands:

?

?

?????? => printenv bootargs

?????? bootargs=root=/dev/ram

?

?????? => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2

?

?????? => printenv bootargs

?????? bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2

?

?????? => bootm 40020000

?????? ## Booting Linux kernel at 40020000 ...

?????? ?? Image Name:? 2.2.13 for NFS on TQM850L

?????? ?? Image Type:??? PowerPC Linux Kernel Image (gzip compressed)

?????? ?? Data Size:?????? 381681 Bytes = 372 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 0000000c

?????? ?? Verifying Checksum ... OK

?????? ?? Uncompressing Kernel Image ... OK

?????? Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000

?????? Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2

?????? time_init: decrementer frequency = 187500000/60

?????? Calibrating delay loop... 49.77 BogoMIPS

?????? Memory: 15208k available (700k kernel code,444k data,32k init) [c0000000,c1000000]

?????? ...

?

If you want to boot a Linux kernel with initial RAM disk,you pass

the memory addresses of both the kernel and the initrd image (PPBCOOT

format!) to the "bootm" command:

?

?????? => imi 40100000 40200000

?

?????? ## Checking Image at 40100000 ...

?????? ?? Image Name:? 2.2.13 for initrd on TQM850L

?????? ?? Image Type:??? PowerPC Linux Kernel Image (gzip compressed)

?????? ?? Data Size:?????? 335725 Bytes = 327 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 0000000c

?????? ?? Verifying Checksum ... OK

?

?????? ## Checking Image at 40200000 ...

?????? ?? Image Name:? Simple Ramdisk Image

?????? ?? Image Type:??? PowerPC Linux RAMDisk Image (gzip compressed)

?????? ?? Data Size:?????? 566530 Bytes = 553 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 00000000

?????? ?? Verifying Checksum ... OK

?

?????? => bootm 40100000 40200000

?????? ## Booting Linux kernel at 40100000 ...

?????? ?? Image Name:? 2.2.13 for initrd on TQM850L

?????? ?? Image Type:??? PowerPC Linux Kernel Image (gzip compressed)

?????? ?? Data Size:?????? 335725 Bytes = 327 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 0000000c

?????? ?? Verifying Checksum ... OK

?????? ?? Uncompressing Kernel Image ... OK

?????? ## Loading RAMDisk Image at 40200000 ...

?????? ?? Image Name:? Simple Ramdisk Image

?????? ?? Image Type:??? PowerPC Linux RAMDisk Image (gzip compressed)

?????? ?? Data Size:?????? 566530 Bytes = 553 kB = 0 MB

?????? ?? Load Address: 00000000

?????? ?? Entry Point:???? 00000000

?????? ?? Verifying Checksum ... OK

?????? ?? Loading Ramdisk ... OK

?????? Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000

?????? Boot arguments: root=/dev/ram

?????? time_init: decrementer frequency = 187500000/60

?????? Calibrating delay loop... 49.77 BogoMIPS

?????? ...

?????? RAMDISK: Compressed image found at block 0

?????? VFS: Mounted root (ext2 filesystem).

?

?????? bash#

?

Boot Linux and pass a flat device tree:

-----------

?

First,U-Boot must be compiled with the appropriate defines. See the section

titled "Linux Kernel Interface" above for a more in depth explanation. The

following is an example of how to start a kernel and pass an updated

flat device tree:

?

=> print oftaddr

oftaddr=0x300000

=> print oft

oft=oftrees/mpc8540ads.dtb

=> tftp $oftaddr $oft

Speed: 1000,full duplex

Using TSEC0 device

TFTP from server 192.168.1.1; our IP address is 192.168.1.101

Filename 'oftrees/mpc8540ads.dtb'.

Load address: 0x300000

Loading: #

done

Bytes transferred = 4106 (100a hex)

=> tftp $loadaddr $bootfile

Speed: 1000,full duplex

Using TSEC0 device

TFTP from server 192.168.1.1; our IP address is 192.168.1.2

Filename 'uImage'.

Load address: 0x200000

Loading:############

done

Bytes transferred = 1029407 (fb51f hex)

=> print loadaddr

loadaddr=200000

=> print oftaddr

oftaddr=0x300000

=> bootm $loadaddr - $oftaddr

## Booting image at 00200000 ...

?? Image Name:? Linux-2.6.17-dirty

?? Image Type:??? PowerPC Linux Kernel Image (gzip compressed)

?? Data Size:?????? 1029343 Bytes = 1005.2 kB

?? Load Address: 00000000

?? Entry Point:???? 00000000

?? Verifying Checksum ... OK

?? Uncompressing Kernel Image ... OK

Booting using flat device tree at 0x300000

Using MPC85xx ADS machine description

Memory CAM mapping: CAM0=256Mb,CAM1=256Mb,CAM2=0Mb residual: 0Mb

[snip]

?

?

More About U-Boot Image Types:

更多 UBOOT 映像

------------------------------

?

U-Boot supports the following image types:

?

?? "Standalone Programs" are directly runnable in the environment

?????? provided by U-Boot; it is expected that (if they behave

?????? well) you can continue to work in U-Boot after return from

?????? the Standalone Program.

?? "OS Kernel Images" are usually images of some Embedded OS which

?????? will take over control completely. Usually these programs

?????? will install their own set of exception handlers,device

?????? drivers,set up the MMU,etc. - this means,that you cannot

?????? expect to re-enter U-Boot except by resetting the CPU.

?? "RAMDisk Images" are more or less just data blocks,and their

?????? parameters (address,size) are passed to an OS kernel that is

?????? being started.

?? "Multi-File Images" contain several images,typically an OS

?????? (Linux) kernel image and one or more data images like

?????? RAMDisks. This construct is useful for instance when you want

?????? to boot over the network using BOOTP etc.,where the boot

?????? server provides just a single image file,but you want to get

?????? for instance an OS kernel and a RAMDisk image.

?

?????? "Multi-File Images" start with a list of image sizes,each

?????? image size (in bytes) specified by an "uint32_t" in network

?????? byte order. This list is terminated by an "(uint32_t)0".

?????? Immediately after the terminating 0 follow the images,one by

?????? one,all aligned on "uint32_t" boundaries (size rounded up to

?????? a multiple of 4 bytes).

?

?? "Firmware Images" are binary images containing firmware (like

?????? U-Boot or FPGA images) which usually will be programmed to

?????? flash memory.

?

?? "Script files" are command sequences that will be executed by

?????? U-Boot's command interpreter; this feature is especially

?????? useful when you configure U-Boot to use a real shell (hush)

?????? as command interpreter.

?

?

Standalone HOWTO:

独立程序

=================

?

One of the features of U-Boot is that you can dynamically load and

run "standalone" applications,which can use some resources of

U-Boot like console I/O functions or interrupt services.

?

Two simple examples are included with the sources:

两个例子

?

"Hello World" Demo:

"Hello World" Demo:

-------------------

?

'examples/hello_world.c' contains a small "Hello World" Demo

application; it is automatically compiled when you build U-Boot.

It's configured to run at address 0x00040004,so you can play with it

like that:

?

?????? => loads

?????? ## Ready for S-Record download ...

?????? ~>examples/hello_world.srec

?????? 1 2 3 4 5 6 7 8 9 10 11 ...

?????? [file transfer complete]

?????? [connected]

?????? ## Start Addr = 0x00040004

?

?????? => go 40004 Hello World! This is a test.

?????? ## Starting application at 0x00040004 ...

?????? Hello World

?????? argc = 7

?????? argv[0] = "40004"

?????? argv[1] = "Hello"

?????? argv[2] = "World!"

?????? argv[3] = "This"

?????? argv[4] = "is"

?????? argv[5] = "a"

?????? argv[6] = "test."

?????? argv[7] = "<NULL>"

?????? Hit any key to exit ...

?

?????? ## Application terminated,rc = 0x0

?

Another example,which demonstrates how to register a CPM interrupt

handler with the U-Boot code,can be found in 'examples/timer.c'.

Here,a CPM timer is set up to generate an interrupt every second.

The interrupt service routine is trivial,just printing a '.'

character,but this is just a demo program. The application can be

controlled by the following keys:

?

?????? ? - print current values og the CPM Timer registers

?????? b - enable interrupts and start timer

?????? e - stop timer and disable interrupts

?????? q - quit application

?

?????? => loads

?????? ## Ready for S-Record download ...

?????? ~>examples/timer.srec

?????? 1 2 3 4 5 6 7 8 9 10 11 ...

?????? [file transfer complete]

?????? [connected]

?????? ## Start Addr = 0x00040004

?

?????? => go 40004

?????? ## Starting application at 0x00040004 ...

?????? TIMERS=0xfff00980

?????? Using timer 1

?????? ? tgcr @ 0xfff00980,tmr @ 0xfff00990,trr @ 0xfff00994,tcr @ 0xfff00998,tcn @ 0xfff0099c,ter @ 0xfff009b0

?

Hit 'b':

?????? [q,b,e,?] Set interval 1000000 us

?????? Enabling timer

Hit '?':

?????? [q,?] ........

?????? tgcr=0x1,tmr=0xff1c,trr=0x3d09,tcr=0x0,tcn=0xef6,ter=0x0

Hit '?':

?????? [q,?] .

?????? tgcr=0x1,tcn=0x2ad4,tcn=0x1efc,tcn=0x169d,ter=0x0

Hit 'e':

?????? [q,?] ...Stopping timer

Hit 'q':

?????? [q,?] ## Application terminated,rc = 0x0

?

?

Minicom warning:

Minicom 警告

================

?

Over time,many people have reported problems when trying to use the

"minicom" terminal emulation program for serial download.

许多人报告说用 minicom 出错。

I (wd)

consider minicom to be broken,and recommend not to use it. Under

Unix,I recommend to use C-Kermit for general purpose use (and

especially for kermit binary protocol download ("loadb" command),and

use "cu" for S-Record download ("loads" command).

建议在 Unix 下使用 C-Kermit

?

Nevertheless,if you absolutely want to use it try adding this

configuration to your "File transfer protocols" section:

?

?????? ?? Name????? ?? Program??????????????? Name U/D FullScr IO-Red. Multi

?????? X? kermit? /usr/bin/kermit -i -l %l -s????? Y??? U????? ?? Y???? ?? N???? ? N

?????? Y? kermit? /usr/bin/kermit -i -l %l -r????? N??? D???? ?? Y???? ?? N???? ? N

?

?

NetBSD Notes:

=============

?

Starting at version 0.9.2,U-Boot supports NetBSD both as host

(build U-Boot) and target system (boots NetBSD/mpc8xx).

?

Building requires a cross environment; it is known to work on

NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also

need gmake since the Makefiles are not compatible with BSD make).

Note that the cross-powerpc package does not install include files;

attempting to build U-Boot will fail because <machine/ansi.h> is

missing.? This file has to be installed and patched manually:

?

?????? # cd /usr/pkg/cross/powerpc-netbsd/include

?????? # mkdir powerpc

?????? # ln -s powerpc machine

?????? # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h

?????? # ${EDIT} powerpc/ansi.h ## must remove __va_list,_BSD_VA_LIST

?

Native builds *don't* work due to incompatibilities between native

and U-Boot include files.

?

Booting assumes that (the first part of) the image booted is a

stage-2 loader which in turn loads and then invokes the kernel

proper. Loader sources will eventually appear in the NetBSD source

tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the

meantime,see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz

?

?

Implementation Internals:

=========================

?

The following is not intended to be a complete description of every

implementation detail. However,it should help to understand the

inner workings of U-Boot and make it easier to port it to custom

hardware.

?

?

Initial Stack,Global Data:

---------------------------

?

The implementation of U-Boot is complicated by the fact that U-Boot

starts running out of ROM (flash memory),usually without access to

system RAM (because the memory controller is not initialized yet).

This means that we don't have writable Data or BSS segments,and BSS

is not initialized as zero. To be able to get a C environment working

at all,we have to allocate at least a minimal stack. Implementation

options for this are defined and restricted by the CPU used: Some CPU

models provide on-chip memory (like the IMMR area on MPC8xx and

MPC826x processors),on others (parts of) the data cache can be

locked as (mis-) used as memory,etc.

?

?????? Chris Hallinan posted a good summary of these issues to the

?????? u-boot-users mailing list:

?

?????? Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?

?????? From: "Chris Hallinan" <clh@net1plus.com>

?????? Date: Mon,10 Feb 2003 16:43:46 -0500 (22:43 MET)

?????? ...

?

?????? Correct me if I'm wrong,folks,but the way I understand it

?????? is this: Using DCACHE as initial RAM for Stack,etc,does not

?????? require any physical RAM backing up the cache. The cleverness

?????? is that the cache is being used as a temporary supply of

?????? necessary storage before the SDRAM controller is setup. It's

?????? beyond the scope of this list to explain the details,but you

?????? can see how this works by studying the cache architecture and

?????? operation in the architecture and processor-specific manuals.

?

?????? OCM is On Chip Memory,which I believe the 405GP has 4K. It

?????? is another option for the system designer to use as an

?????? initial stack/RAM area prior to SDRAM being available. Either

?????? option should work for you. Using CS 4 should be fine if your

?????? board designers haven't used it for something that would

?????? cause you grief during the initial boot! It is frequently not

?????? used.

?

?????? CFG_INIT_RAM_ADDR should be somewhere that won't interfere

?????? with your processor/board/system design. The default value

?????? you will find in any recent u-boot distribution in

?????? walnut.h should work for you. I'd set it to a value larger

?????? than your SDRAM module. If you have a 64MB SDRAM module,set

?????? it above 400_0000. Just make sure your board has no resources

?????? that are supposed to respond to that address! That code in

?????? start.S has been around a while and should work as is when

?????? you get the config right.

?

?????? -Chris Hallinan

?????? DS4.COM,Inc.

?

It is essential to remember this,since it has some impact on the C

code for the initialization procedures:

?

* Initialized global data (data segment) is read-only. Do not attempt

? to write it.

?

* Do not use any uninitialized global data (or implicitely initialized

? as zero data - BSS segment) at all - this is undefined,initiali-

? zation is performed later (when relocating to RAM).

?

* Stack space is very limited. Avoid big data buffers or things like

? that.

?

Having only the stack as writable memory limits means we cannot use

normal global data to share information beween the code. But it

turned out that the implementation of U-Boot can be greatly

simplified by making a global data structure (gd_t) available to all

functions. We could pass a pointer to this data as argument to _all_

functions,but this would bloat the code. Instead we use a feature of

the GCC compiler (Global Register Variables) to share the data: we

place a pointer (gd) to the global data into a register which we

reserve for this purpose.

?

When choosing a register for such a purpose we are restricted by the

relevant? (E)ABI? specifications for the current architecture,and by

GCC's implementation.

?

For PowerPC,the following registers have specific use:

?????? R1:? stack pointer

?????? R2:? reserved for system use

?????? R3-R4:?? parameter passing and return values

?????? R5-R10: parameter passing

?????? R13:?????? small data area pointer

?????? R30:?????? GOT pointer

?????? R31:?????? frame pointer

?

?????? (U-Boot also uses R14 as internal GOT pointer.)

?

??? ==> U-Boot will use R2 to hold a pointer to the global data

?

??? Note: on PPC,we could use a static initializer (since the

??? address of the global data structure is known at compile time),

??? but it turned out that reserving a register results in somewhat

??? smaller code - although the code savings are not that big (on

??? average for all boards 752 bytes for the whole U-Boot image,

??? 624 text + 127 data).

?

On Blackfin,the normal C ABI (except for P5) is followed as documented here:

?????? http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface

?

??? ==> U-Boot will use P5 to hold a pointer to the global data

?

On ARM,the following registers are used:

?

?????? R0:? function argument word/integer result

?????? R1-R3:?? function argument word

?????? R9:? GOT pointer

?????? R10:?????? stack limit (used only if stack checking if enabled)

?????? R11:?????? argument (frame) pointer

?????? R12:?????? temporary workspace

?????? R13:?????? stack pointer

?????? R14:?????? link register

?????? R15:?????? program counter

?

??? ==> U-Boot will use R8 to hold a pointer to the global data

?

NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,

or current versions of GCC may "optimize" the code too much.

?

Memory Management:

------------------

?

U-Boot runs in system state and uses physical addresses,i.e. the

MMU is not used either for address mapping nor for memory protection.

?

The available memory is mapped to fixed addresses using the memory

controller. In this process,a contiguous block is formed for each

memory type (Flash,SDRAM,SRAM),even when it consists of several

physical memory banks.

?

U-Boot is installed in the first 128 kB of the first Flash bank (on

TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After

booting and sizing and initializing DRAM,the code relocates itself

to the upper end of DRAM. Immediately below the U-Boot code some

memory is reserved for use by malloc() [see CFG_MALLOC_LEN

configuration setting]. Below that,a structure with global Board

Info data is placed,followed by the stack (growing downward).

?

Additionally,some exception handler code is copied to the low 8 kB

of DRAM (0x00000000 ... 0x00001FFF).

?

So a typical memory configuration with 16 MB of DRAM could look like

this:

?

?????? 0x0000 0000?????? Exception Vector code

?????? ????? :

?????? 0x0000 1FFF

?????? 0x0000 2000?????? Free for Application Use

?????? ????? :

?????? ????? :

?

?????? ????? :

?????? ????? :

?????? 0x00FB FF20????? Monitor Stack (Growing downward)

?????? 0x00FB FFAC???? Board Info Data and permanent copy of global data

?????? 0x00FC 0000????? Malloc Arena

?????? ????? :

?????? 0x00FD FFFF

?????? 0x00FE 0000?????? RAM Copy of Monitor Code

?????? ...?????????? eventually: LCD or video framebuffer

?????? ...?????????? eventually: pRAM (Protected RAM - unchanged by reset)

?????? 0x00FF FFFF????? [End of RAM]

?

?

System Initialization:

----------------------

?

In the reset configuration,U-Boot starts at the reset entry point

(on most PowerPC systems at address 0x00000100). Because of the reset

configuration for CS0# this is a mirror of the onboard Flash memory.

To be able to re-map memory U-Boot then jumps to its link address.

To be able to implement the initialization code in C,a (small!)

initial stack is set up in the internal Dual Ported RAM (in case CPUs

which provide such a feature like MPC8xx or MPC8260),or in a locked

part of the data cache. After that,U-Boot initializes the CPU core,

the caches and the SIU.

?

Next,all (potentially) available memory banks are mapped using a

preliminary mapping. For example,we put them on 512 MB boundaries

(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000,Flash

on 0x40000000 and 0x60000000,SRAM on 0x80000000). Then UPM A is

programmed for SDRAM access. Using the temporary configuration,a

simple memory test is run that determines the size of the SDRAM

banks.

?

When there is more than one SDRAM bank,and the banks are of

different size,the largest is mapped first. For equal size,the first

bank (CS2#) is mapped first. The first mapping is always for address

0x00000000,with any additional banks following immediately to create

contiguous memory starting from 0.

?

Then,the monitor installs itself at the upper end of the SDRAM area

and allocates memory for use by malloc() and for the global Board

Info data; also,the exception vector code is copied to the low RAM

pages,and the final stack is set up.

?

Only after this relocation will you have a "normal" C environment;

until that you are restricted in several ways,mostly because you are

running from ROM,and because the code will have to be relocated to a

new address in RAM.

?

?

U-Boot Porting Guide:

----------------------

?

[Based on messages by Jerry Van Baren in the U-Boot-Users mailing

list,October 2002]

?

?

int main (int argc,char *argv[])

{

?????? sighandler_t no_more_time;

?

?????? signal (SIGALRM,no_more_time);

?????? alarm (PROJECT_DEADLINE - toSec (3 * WEEK));

?

?????? if (available_money > available_manpower) {

????????????? pay consultant to port U-Boot;

????????????? return 0;

?????? }

?

?????? Download latest U-Boot source;

?

?????? Subscribe to u-boot-users mailing list;

?

?????? if (clueless) {

????????????? email ("Hi,I am new to U-Boot,how do I get started?");

?????? }

?

?????? while (learning) {

????????????? Read the README file in the top level directory;

????????????? Read http://www.denx.de/twiki/bin/view/DULG/Manual ;

????????????? Read the source,Luke;

?????? }

?

?????? if (available_money > toLocalCurrency ($2500)) {

????????????? Buy a BDI2000;

?????? } else {

????????????? Add a lot of aggravation and time;

?????? }

?

?????? Create your own board support subdirectory;

?

?????? Create your own board config file;

?

?????? while (!running) {

????????????? do {

???????????????????? Add / modify source code;

????????????? } until (compiles);

????????????? Debug;

????????????? if (clueless)

???????????????????? email ("Hi,I am having problems...");

?????? }

?????? Send patch file to Wolfgang;

?

?????? return 0;

}

?

void no_more_time (int sig)

{

????? hire_a_guru();

}

?

?

Coding Standards:

-----------------

?

All contributions to U-Boot should conform to the Linux kernel

coding style; see the file "Documentation/CodingStyle" and the script

"scripts/Lindent" in your Linux kernel source directory.? In sources

originating from U-Boot a style corresponding to "Lindent -pcs" (adding

spaces before parameters to function calls) is actually used.

?

Source files originating from a different project (for example the

MTD subsystem) are generally exempt from these guidelines and are not

reformated to ease subsequent migration to newer versions of those

sources.

?

Please note that U-Boot is implemented in C (and to some small parts in

Assembler); no C++ is used,so please do not use C++ style comments (//)

in your code.

?

Please also stick to the following formatting rules:

- remove any trailing white space

- use TAB characters for indentation,not spaces

- make sure NOT to use DOS '/r/n' line feeds

- do not add more than 2 empty lines to source files

- do not add trailing empty lines to source files

?

Submissions which do not conform to the standards may be returned

with a request to reformat the changes.

?

?

Submitting Patches:

-------------------

?

Since the number of patches for U-Boot is growing,we need to

establish some rules. Submissions which do not conform to these rules

may be rejected,even when they contain important and valuable stuff.

?

Patches shall be sent to the u-boot-users mailing list.

?

Please see http://www.denx.de/wiki/U-Boot/Patches for details.

?

When you send a patch,please include the following information with

it:

?

* For bug fixes: a description of the bug and how your patch fixes

? this bug. Please try to include a way of demonstrating that the

? patch actually fixes something.

?

* For new features: a description of the feature and your

? implementation.

?

* A CHANGELOG entry as plaintext (separate from the patch)

?

* For major contributions,your entry to the CREDITS file

?

* When you add support for a new board,don't forget to add this

? board to the MAKEALL script,too.

?

* If your patch adds new configuration options,don't forget to

? document these in the README file.

?

* The patch itself. If you are using git (which is *strongly*

? recommended) you can easily generate the patch using the

? "git-format-patch". If you then use "git-send-email" to send it to

? the U-Boot mailing list,you will avoid most of the common problems

? with some other mail clients.

?

? If you cannot use git,use "diff -purN OLD NEW". If your version of

? diff does not support these options,then get the latest version of

? GNU diff.

?

? The current directory when running this command shall be the parent

? directory of the U-Boot source tree (i. e. please make sure that

? your patch includes sufficient directory information for the

? affected files).

?

? We prefer patches as plain text. MIME attachments are discouraged,

? and compressed attachments must not be used.

?

* If one logical set of modifications affects or creates several

? files,all these changes shall be submitted in a SINGLE patch file.

?

* Changesets that contain different,unrelated modifications shall be

? submitted as SEPARATE patches,one patch per changeset.

?

?

Notes:

?

* Before sending the patch,run the MAKEALL script on your patched

? source tree and make sure that no errors or warnings are reported

? for any of the boards.

?

* Keep your modifications to the necessary minimum: A patch

? containing several unrelated changes or arbitrary reformats will be

? returned with a request to re-formatting / split it.

?

* If you modify existing code,make sure that your new code does not

? add to the memory footprint of the code ;-) Small is beautiful!

? When adding new features,these should compile conditionally only

? (using #ifdef),and the resulting code with the new feature

? disabled must not need more memory than the old code without your

? modification.

?

* Remember that there is a size limit of 40 kB per message on the

? u-boot-users mailing list. Bigger patches will be moderated. If

? they are reasonable and not bigger than 100 kB,they will be

? acknowledged. Even bigger patches should be avoided.