u-boot移植前的准备工作：
1 下载源码，建立工作目录
Uboot的源码可以从以下网址下载：http://downloads.sourceforge.net/u-boot/u-boot-1.1.4.tar.bz2?modtime=1134752480&big_mirror=0
我们这里下载的是u-boot-1.1.4.tar.bz2
建立工作目录：
mkdir /root/build_uboot
cd /root/build_uboot
把下载的源码拷贝到该目录,解压；
tar jxvf u-boot-1.1.4.tar.bz2
mv u-boot-1.1.4 u-boot
2 确定分区：
u-boot移植的具体步骤：
一 建立适合的board平台
参照board/smdk2410目录，我们在源码的board下建立自己的自己的平台gec2410，步骤如下.
1 修改顶层Makefile
cd /root/build_uboot/u-boot
vi Makefile
找到：
smdk2410_config : unconfig
@./mkconfig $(@:_config=) arm arm920t smdk2410 NULL s3c24x0
在其后面添加：
gec2410_config : unconfig
@./mkconfig $(@:_config=) arm arm920t gec2410 NULL s3c24x0
各项的意思如下:
arm:??????? CPU的架构(ARCH)
arm920t:??? CPU的类型(CPU)，其对应于cpu/arm920t子目录。
gec2410:??? 开发板的型号(BOARD)，对应于board/gec2410目录。
NULL:?????? 开发者/或经销商(vender)。
s3c24x0:??? 片上系统(SOC)。
我把我的板子起名叫gec2410，可以依自己的喜好修改
2 建立board/gec2410目录，拷贝board/smdk2410下的文件到board/gec2410目录，将smdk2410.c更名为gec2410.c
cp -r board/smdk2410 board/gec2410
3 修改board/gec2410/Makefile
将：
OBJS??? := smdk2410.o flash.o
改为：
OBJS???? := gec2410.o flash.o
4 cp include/configs/smdk2410.h include/configs/gec2410.h
5 修改cpu/arm920t/config.mk文件
将：
PLATFORM_CPPFLAGS +=$(call cc-option,-mapcs-32,-mabi=apcs-gnu)
改为：
PLATFORM_CPPFLAGS +=$(call cc-option,$(call cc-option,-mabi=apcs-gnu),)
6 设置交叉编译环境变量
export PATH=/usr/local/arm/2.95.3/bin:$PATH
7 测试编译能否成功：
make gec2410_config
make all ARCH=arm
生成u-boot.bin就OK了
二 支持网络和 nand flash操作命令
1 添加网络命令
在include/configs/gec2410.h
只要在
#define CONFIG_COMMANDS
添加定义
????????????????????????? CFG_CMD_NET
????????????????????????? CFG_CMD_PING
就可以了
??? 说明：include/configs/gec2410.h文件是与开发板相关的配置头文件。
2 支持nand flash启动和读写
(1) 支持从nand flash 启动
a 添加nandflash寄存器的定义
修改include/configs/gec2410.h文件，添加如下内容：
***********************************************************************************************
/*
* Nandflash Boot
*/
#define CONFIG_S3C2410_NAND_BOOT 1
#define STACK_BASE??? 0x33f00000
#define STACK_SIZE??? 0x8000
#define UBOOT_RAM_BASE??? 0x33f80000
/* NAND Flash Controller */
#define NAND_CTL_BASE??????????? 0x4E000000
#define bINT_CTL(Nb)??????? __REG(INT_CTL_BASE + (Nb))
/* Offset */
#define oNFCONF?????????????? 0x00
#define oNFCMD??????????????? 0x04
#define oNFADDR?????????????? 0x08
#define oNFDATA?????????????? 0x0c
#define oNFSTAT?????????????? 0x10
#define oNFECC??????????????? 0x14
************************************************************************************************
b 在start.S加入搬运代码
修改cpu/arm920t/start.S文件
在ldr pc,_start_armboot之前加入：
************************************************************************************************
#ifdef CONFIG_S3C2410_NAND_BOOT
bl??? copy_myself
@ jump to ram
ldr?? r1,=on_the_ram
add pc,r1,#0
nop
nop
1:??? b???? 1b????????? @ infinite loop
on_the_ram:
#endif
************************************************************************************************
在_start_armboot: .word start_armboot之后加入：
************************************************************************************************
#ifdef CONFIG_S3C2410_NAND_BOOT
copy_myself:
mov r10,lr
@ reset NAND
mov r1,#NAND_CTL_BASE
ldr?? r2,=0xf830?????????? @ initial value
str?? r2,[r1,#oNFCONF]
ldr?? r2,#oNFCONF]
bic r2,r2,#0x800????????????? @ enable chip
str?? r2,#oNFCONF]
mov r2,#0xff???????? @ RESET command
strb r2,#oNFCMD]
mov r3,#0?????????????????? @ wait
1:add r3,r3,#0x1
cmp r3,#0xa
blt?? 1b
2:ldr?? r2,#oNFSTAT]????? @ wait ready
tst??? r2,#0x1
beq 2b
ldr?? r2,#oNFCONF]
orr r2,#0x800????????????? @ disable chip
str?? r2,#oNFCONF]
@ get read to call C functions (for nand_read())
ldr?? sp,DW_STACK_START?????? @ setup stack pointer
mov fp,#0??????????????????? @ no previous frame,so fp=0
@ copy vivi to RAM
ldr?? r0,=UBOOT_RAM_BASE
mov???? r1,#0x0
mov r2,#0x20000
bl??? nand_read_ll
tst??? r0,#0x0
beq ok_nand_read
#ifdef CONFIG_DEBUG_LL
bad_nand_read:
ldr?? r0,STR_FAIL
ldr?? r1,SerBase
bl??? PrintWord
1:b???? 1b????????? @ infinite loop
#endif
ok_nand_read:
#ifdef CONFIG_DEBUG_LL
ldr?? r0,STR_OK
ldr?? r1,SerBase
bl??? PrintWord
#endif
@ verify
mov r0,#0
ldr?? r1,=UBOOT_RAM_BASE
mov r2,#0x400???? @ 4 bytes * 1024 = 4K-bytes
go_next:
ldr?? r3,[r0],#4
ldr?? r4,[r1],#4
teq?? r3,r4
bne notmatch
subs r2,#4
beq done_nand_read
bne go_next
notmatch:
#ifdef CONFIG_DEBUG_LL
sub r0,r0,#4
ldr?? r1,SerBase
bl??? PrintHexWord
ldr?? r0,SerBase
bl??? PrintWord
#endif
1:b???? 1b
done_nand_read:
#ifdef CONFIG_DEBUG_LL
ldr?? r0,SerBase
bl??? PrintWord
#endif
mov pc,r10
@ clear memory
@ r0: start address
@ r1: length
mem_clear:
mov r2,#0
mov r3,r2
mov r4,r2
mov r5,r2
mov r6,r2
mov r7,r2
mov r8,r2
mov r9,r2
clear_loop:
stmia????? r0!,{r2-r9}
subs r1,#(8 * 4)
bne clear_loop
mov pc,lr
#endif @ CONFIG_S3C2410_NAND_BOOT
************************************************************************************************
在文件的最后加入如下，堆栈地址：
*************************************************************************************************
?? .align???? 2
DW_STACK_START:
.word????? STACK_BASE+STACK_SIZE-4
*************************************************************************************************
c 添加nand_read_ll函数的实现
在board/gec2410/建立nand_read.c，加入如下内容(copy from vivi)：
*************************************************************************************************
#include <config.h>
#define __REGb(x) (*(volatile unsigned char *)(x))
#define __REGi(x) (*(volatile unsigned int *)(x))
#define NF_BASE 0x4e000000
#define NFCONF __REGi(NF_BASE + 0x0)
#define NFCMD __REGb(NF_BASE + 0x4)
#define NFADDR __REGb(NF_BASE + 0x8)
#define NFDATA __REGb(NF_BASE + 0xc)
#define NFSTAT __REGb(NF_BASE + 0x10)
#define BUSY 1
inline void wait_idle(void) {
??? int i;
??? while(!(NFSTAT & BUSY))
????? for(i=0; i<10; i++);
}
#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)
/* low level nand read function */
int
nand_read_ll(unsigned char *buf,unsigned long start_addr,int size)
{
??? int i,j;
??? if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
??????? return -1; /* invalid alignment */
??? }
??? /* chip Enable */
??? NFCONF &= ~0x800;
??? for(i=0; i<10; i++);
???? for(i=start_addr; i < (start_addr + size);) {
????? /* READ0 */
????? NFCMD = 0;
?????? /* Write Address */
????? NFADDR = i & 0xff;
????? NFADDR = (i >> 9) & 0xff;
????? NFADDR = (i >> 17) & 0xff;
????? NFADDR = (i >> 25) & 0xff;
?????? wait_idle();
?????? for(j=0; j < NAND_SECTOR_SIZE; j++,i++) {
*buf = (NFDATA & 0xff);
buf++;
????? }
??? }
???? /* chip Disable */
??? NFCONF |= 0x800; /* chip disable */
??? return 0;
}
************************************************************************************************
修改board/gec2410/Makefile为
OBJS := gec2410.o flash.o nand_read.o
以上步骤就可以把u-boot烧写到nandflash上了
2） 支持nand flash操作命令
a 在/include/configs/gec2410.h文件中添加宏定义
#define CONFIG_COMMANDS
添加定义
????????????????????????? CFG_CMD_NAND
??????????????????????? CFG_CMD_ENV????????
b 定义环境变量宏
#define CFG_ENV_IS_IN_FLASH 1
#define CFG_ENV_SIZE?????????????? 0x10000 /* Total Size of Environment Sector */
改为
#define CFG_ENV_IS_IN_NAND??????? 1
#define CFG_ENV_OFFSET???????????? 0x030000
#define CFG_NAND_BASE??? 0x4E000000
#define CMD_SAVEENV
#define CFG_NAND_LEGACY
#define CFG_ENV_SIZE?????????????? 0x10000 /* Total Size of Environment Sector */???????????????????????
/*set env*/
#define CFG_MONITOR_BASE PHYS_SDRAM_1
c 修改common/cmd_nand.c文件，添加nand flash初始化函数
添加
**************************************************************************************************
#define rNFCONF (*(volatile unsigned *)0x4E000000)
#define rNFCMD (*(volatile unsigned *)0x4E000004)
#define rNFADDR (*(volatile unsigned *)0x4E000008)
#define rNFDATA (*(volatile unsigned *)0x4E00000C)
#define rNFSTAT (*(volatile unsigned *)0x4E000010)
#define rNFECC (*(volatile unsigned *)0x4E000014)
#define CFG_NAND_BASE??? 0x4E000000
#define CFG_MAX_NAND_DEVICE 1 /* Max number of NAND devices */
#define SECTORSIZE 512
#define ADDR_COLUMN 1
#define ADDR_PAGE 2
#define ADDR_COLUMN_PAGE 3
#define NAND_ChipID_UNKNOWN 0x00
#define NAND_MAX_FLOORS 1
#define NAND_MAX_CHIPS 1
#define NAND_WAIT_READY(nand) {while(!(rNFSTAT&(1<<0)));}
#define NAND_DISABLE_CE(nand) {rNFCONF|=(1<<11);}
#define NAND_ENABLE_CE(nand) {rNFCONF&=~(1<<11);}
#define WRITE_NAND_COMMAND(d,adr) {rNFCMD=d;}
#define WRITE_NAND_ADDRESS(d,adr) {rNFADDR=d;}
#define WRITE_NAND(d,adr) {rNFDATA=d;}
#define READ_NAND(adr)???????? (rNFDATA)
/* the following functions are NOP's because S3C24X0 handles this in hardware */
#define NAND_CTL_CLRALE(nandptr)
#define NAND_CTL_SETALE(nandptr)
#define NAND_CTL_CLRCLE(nandptr)
#define NAND_CTL_SETCLE(nandptr)
#define CONFIG_MTD_NAND_VERIFY_WRITE 1
********************************************************************************************************
添加nand_init()函数的实现
*******************************************************************************************************
void nand_init(void)
{
???????? int i;
???????? unsigned long j;
???????? rNFCONF=(1<<15)|(1<<14)|(1<<13)|(1<<12)|(1<<11)|(0<<8)|(3<<4)|(0<<0);
????????
???????? rNFCONF=rNFCONF&~(1<<11);
???????? rNFCMD=0xff;
????????????????
???????? for(i=0;i<10;i++);
???????? while(!(rNFSTAT&(1<<0)));
????????
???????? rNFCONF=rNFCONF|(1<<11);
???????? j=nand_probe(0x4e000000);
???????? printf("nand flash : %4lu MBn",j>>20);
}
********************************************************************************************************
d 在nand_probe函数中添加一行
********************************************************************************************************
#endif
???????? oob_config.badblock_pos = 5;
??????? nand_dev_desc[0].ChipID = 0x00;
********************************************************************************************************
uboot移植完成！
配置编译
export PATH=/usr/local/arm/2.95.3/bin:$PATH
make gec2410_config
make ARCH=arm all
u-boot的测试
把u-boot烧写到nand flash上
启动信息：
*************************************************************
U-Boot 1.1.4 (Feb 10 2007 - 23:56:56)???????????????
????????????????????????????????????????????????????
U-Boot code: 33F80000 -> 33F9C5D0 BSS: -> 33FA06B8
RAM Configuration:
Bank #0: 30000000 64 MB
Flash: 512 kB
nand flash :?? 64 MB
In:??? serial
Out:?? serial
Err:?? serial
GEC2410#
**************************************************************
tftp 30008000 zImage
go 300080000
出现错误，因为go命令的实现函数不完整。
下面完善go命令的实现函数do_go()
三 完善do_go函数
gedit common/cmd_boot.c
添加
/*添加call_linux函数*/
********************************************************************************
void call_linux(long a0,long a1,long a2)
{??
__asm__(
???????????? "?? mov r1,#0n"
???????????? "?? mov r1,#7 << 5n"??????? /* 8 segments */
???????????? "1: orr r3,#63 << 26n"????? /* 64 entries */
???????????? "2: mcr p15,c7,c14,2n" /* clean & invalidate D index */
???????????? "?? subs??? r3,#1 << 26n"
???????????? "?? bcs 2bn"???????????? /* entries 64 to 0 */
???????????? "?? subs??? r1,#1 << 5n"
???????????? "?? bcs 1bn"???????????? /* segments 7 to 0 */
???????????? "?? mcr p15,c5,0n" /* invalidate I cache */
???????????? "?? mcr p15,c10,4n" /* drain WB */
);
__asm__(
"mov??? r0,#0n"
"mcr??? p15,4n"?? /* drain WB */
"mcr??? p15,c8,0n"??? /* invalidate I & D TLBs */
);
__asm__(
"mov??? r0,%0n"
"mov??? r1,#0x0c1n"
"mov??? r2,%2n"
"mov??? ip,ip,c13,c0,0n"?? /* zero PID */
"mcr??? p15,0n"??? /* invalidate I,D caches */
"mcr??? p15,4n"?? /* drain write buffer */
"mcr??? p15,D TLBs */
"mrc??? p15,c1,0n"??? /* get control register */
"bic??? ip,#0x0001n"????? /* disable MMU */
"mcr??? p15,0n"??? /* write control register */
"mov??? pc,r2n"
"nopn"
"nopn"
: /* no outpus */
: "r" (a0),"r" (a1),"r" (a2)
);
}
****************************************************************************
添加setup_linux_param函数
****************************************************************************
static void setup_linux_param(ulong param_base)
{??
struct param_struct *params = (struct param_struct *)param_base;
char *linux_cmd;
//linux_cmd = "noinitrd root=/dev/mtdblock/2 init=/linuxrc console=ttyS0";
linux_cmd = getenv("bootargs");
memset(params,sizeof(struct param_struct));
params->u1.s.page_size = 0x00001000;
params->u1.s.nr_pages = (0x04000000 >> 12);
/* set linux command line */
memcpy(params->commandline,linux_cmd,strlen(linux_cmd) + 1);
}
****************************************************************************
在do_go()函数中添加
****************************************************************************
printf ("## Starting application at 0x%08lX ...n",addr);
???????? setup_linux_param(0x30000100);
???????? call_linux(0,0x0c1,0x30008000);
???????? printf("okn");
****************************************************************************
3重新编译u-boot
make all ARCH=arm
通过jtag将u-boot烧写到flash中就可以从NAND flash启动了
U-BOOT常用命令介绍
printenv?? 打印环境变量
setenv???? 设置环境变量
如：setenv ipaddr 172.22.60.44
????? Setenv serverip 172.22.60.88
saveenv??????? 保存设定的环境变量
我们经常要设置的环境变量有ipaddr,serverip，bootcmd，bootargs。
tftp?????? 即将内核镜像文件从PC中下载到SDRAM的指定地址，然后通过bootm来引导内核，前提是所用PC要安装设置tftp服务。
如: tftp 30008000 zImage
nand erase 擦除nand flash中数据块 如：nand erase 0x40000 0x1c0000 ?????????????? 起始地址 大小 nand write 把RAM中的数据写到Nand Flash中 如：nand write 0x30008000 0x40000 0x1c0000 nand read?? 从nand flash中读取数据到RAM 如：nand read 0x30008000 0x40000 0x1c0000 go????????? 直接跳转到可执行文件的入口地址，执行可执行文件。 下载并烧写内核如下 1 用网线连接开发板和PC机 2 启动U-BOOT并设置环境变量 setenv ipaddr 172.22.60.32 //设置开发板的IP setenv serverip 172.22.60.99 //设置PC机的IP setenv ethaddr 11.22.33.44.55.66 //设置开发板的物理地址 saveenv //保存 3 在PC机端打开TFTP服务器，并且把要下载的文件拷贝到tftp服务器程序所在的目录下 4 下载和烧写 在u-boot下用以下命令 ??? tftp 30008000 zImage nand erase 40000 1c0000 nand write 30008000 40000 1c0000
