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mini2440开发板中启动代码2440INIT.S分析

发布时间:2020-12-15 06:49:15 所属栏目:百科 来源:网络整理
导读:? 声明:文章转自别处,非本人自创 http://hi.baidu.com/haijie0707/blog/item/6ff41a3bff7ccef93a87ced5.html;========================================= ; NAME: 2440INIT.S ; DESC: C start up codes ; Configure memory,ISR,stacks ; Initialize C-varia
?
声明:文章转自别处,非本人自创
http://hi.baidu.com/haijie0707/blog/item/6ff41a3bff7ccef93a87ced5.html
;========================================= 
; NAME: 2440INIT.S 
; DESC: C start up codes 
;       Configure memory,ISR,stacks 
; Initialize C-variables 
; HISTORY: 
; 2002.02.25:kwtark: ver 0.0 
; 2002.03.20:purnnamu: Add some s for testing STOP,Sleep mode 
; 2003.03.14:DonGo: Modified for 2440. 
;========================================= 
 
;首先,启动代码定义了一些常量 
;汇编不能使用include包含头文件,所有用Get
;汇编也不认识*.h 文件,所有只能用*.inc
?GET option.inc??? ;定义芯片相关的配置
?GET memcfg.inc??? ;定义存储器配置
?GET 2440addr.inc? ;定义了寄存器符号

;REFRESH寄存器[22]bit : 0- auto refresh; 1 - self refresh

;用于节电模式中,SDRAM自动刷新

BIT_SELFREFRESH EQU (1<<22)
?
;处理器模式常量: CPSR寄存器的后5位决定目前处理器模式 M[4:0]
USERMODE    EQU  0x10 
FIQMODE     EQU  0x11 
IRQMODE     EQU  0x12 
SVCMODE     EQU  0x13 
ABORTMODE   EQU  0x17 
UNDEFMODE   EQU  0x1b 
MODEMASK    EQU  0x1f 
NOINT       EQU  0xc0 
 
;定义处理器各模式下堆栈地址常量 
;_STACK_BASEADDRESS定义在option.inc中
UserStack EQU (_STACK_BASEADDRESS-0x3800)    ;0x33ff4800 ~ 
SVCStack EQU (_STACK_BASEADDRESS-0x2800)     ;0x33ff5800 ~ 
UndefStack EQU (_STACK_BASEADDRESS-0x2400)   ;0x33ff5c00 ~ 
AbortStack EQU (_STACK_BASEADDRESS-0x2000)   ;0x33ff6000 ~ 
IRQStack EQU (_STACK_BASEADDRESS-0x1000)     ;0x33ff7000 ~ 
FIQStack EQU (_STACK_BASEADDRESS-0x0)        ;0x33ff8000 ~ 
 
;arm处理器有两种工作状态 1.arm:32位 这种工作状态下执行字对准的arm指令 2.Thumb:16位 这种工状;态执行半字对准的Thumb指令
;因为处理器分为16位 32位两种工作状态 程序的编译器也是分16位和32两种编译方式 所以下面的程序用
;于根据处理器工作状态确定编译器编译方式
;code16伪指令指示汇编编译器后面的指令为16位的thumb指令
;code32伪指令指示汇编编译器后面的指令为32位的arm指令
;
;Arm上电时处于ARM状态,故无论指令为ARM集或Thumb集,都先强制成ARM集,待init.s初始化完成后
;再根据用户的编译配置转换成相应的指令模式。为此,定义变量THUMBCODE作为指示,跳转到main之前
;根据其值切换指令模式
;
;这段是为了统一目前的处理器工作状态和软件编译方式(16位编译环境使用tasm.exe编译
;检查在tasm.exe里是否设置了采用THUMB(16位)代码(armasm -16 ...@ADS 1.0)
?
?
?GBLL THUMBCODE?????????????? ?;定义THUMBCODE全局变量
?? [ {CONFIG} = 16?
???????????????????????????????? ;如果发现是在用16位代码的话(编译选项中指定使用thumb指令
???? THUMBCODE SETL {TRUE} ?? ;把THUMBCODE设置为TURE ????
?????? CODE32 ?????????????????? ;把处理器从新设置成为ARM模式 ????????
??????? ?| ????????????????????? ;如果处理器现在就是ARM模式
??? THUMBCODE SETL {FALSE}?? ;把THUMBCODE设置为FALSE就行了 ???
?? ] ??
?MACRO?
??????????????;一个根据THUMBCODE把PC寄存的值保存到LR的宏,宏 MOV_PC_LR
? MOV_PC_LR [?? THUMBCODE bx lr?? ;([表示if)
????????????????????????????????????? ;在ARM模式中要使用BX指令转跳到THUMB指令,并转换模式
|????????? ;(|表示else)如果编译选项本来就指定为ARM模式

mov pc,lr? ;如果目标地址也是ARM指令的话就采用这种方式
]?????????????? ;(]表示endif)
MEND

MACRO??????????? ?;和上面的宏一样,只是多了一个相等的条件
MOVEQ_PC_LR
[???? THUMBCODE
bxeq lr
|
moveq pc,lr
]
MEND

;=======================================================================================
;下面这个宏是用于第一次查表过程的实现中断向量的重定向,如果你比较细心的话就是发现
;在_ISR_STARTADDRESS=0x33FF_FF00里定义的第一级中断向量表是采用型如Handle***的方式的.
;而在程序的ENTRY处(程序开始处)采用的是b Handler***的方式.
;在这里Handler***就是通过HANDLER这个宏和Handle***进立联系的.
;这种方式的优点就是正真定义的向量数据在内存空间里,而不是在ENTRY处的ROM(FLASH)空间里,
;这样,我们就可以在程序里灵活的改动向量的数据了.
;========================================================================================?
;;这段程序用于把中断服务程序的首地址装载到pc中,有人称之为“加载程序”。
;本初始化程序定义了一个数据区(在文件最后),34个字空间,存放相应中断服务程序的首地址。每个字
;空间都有一个标号,以Handle***命名。
;在向量中断模式下使用“加载程序”来执行中断服务程序。
;这里就必须讲一下向量中断模式和非向量中断模式的概念
;向量中断模式是当cpu读取位于0x18处的IRQ中断指令的时候,系统自动读取对应于该中断源确定地址上的;
;指令取代0x18处的指令,通过跳转指令系统就直接跳转到对应地址
;函数中 节省了中断处理时间提高了中断处理速度标 例如 ADC中断的向量地址为0xC0,则在0xC0处放如下
;代码:ldr PC,=HandlerADC 当ADC中断产生的时候系统会
;自动跳转到HandlerADC函数中
;非向量中断模式处理方式是一种传统的中断处理方法,当系统产生中断的时候,系统将interrupt
;pending寄存器中对应标志位置位 然后跳转到位于0x18处的统一中断
;函数中 该函数通过读取interrupt pending寄存器中对应标志位 来判断中? 断? 源 并根据优先级关系再跳到
;对应中断源的处理代码中
;

MACRO
$HandlerLabel HANDLER $HandleLabel

$HandlerLabel?????? ;标号

sub sp,sp,#4??????? ;减少sp(用于存放转跳地址)
stmfd sp!,{r0}????? ;把工作寄存器压入栈(lr does not push because it return to original
address)
ldr???? r0,=$HandleLabel??? ;将HandleXXX的址址放入r0
ldr???? r0,[r0]????????????????????????? ;把HandleXXX所指向的内容(也就是中断程序的入口)放入r0
str???? r0,[sp,#4]?????????????????? ?;把中断服务程序(ISR)压入栈
ldmfd?? sp!,{r0,pc}???????????? ? ;用出栈的方式恢复r0的原值和为pc设定新值(也就完成了到ISR的转跳)
MEND


;=========================================================================================
;在这里用IMPORT伪指令(和c语言的extren一样)引入|Image$$RO$$Base|,|Image$$RO$$Limit|...
;这些变量是通过ADS的工程设置里面设定的RO Base和RW Base设定的,
;最终由编译脚本和连接程序导入程序.
;那为什么要引入这玩意呢,最简单的用处是可以根据它们拷贝自已
;==========================================================================================
IMPORT? |Image$$RO$$Base|?? ; ROM code(也就是代码)的开始地址
IMPORT? |Image$$RO$$Limit|?? ?; ROM code的结束地址 (=ROM data的开始地址)
IMPORT? |Image$$RW$$Base|?? ; 要初始化的RAM的开始地址
IMPORT? |Image$$ZI$$Base|???? ?; area(需要清零的RAM区域)的开始地址
IMPORT? |Image$$ZI$$Limit|??? ?? ; area的结束地址

;这里引入一些在其它文件中实现在函数,包括为我们所熟知的main函数
IMPORT MMU_SetAsyncBusMode
IMPORT MMU_SetFastBusMode ;hzh?

?

?

?


IMPORT?Main

  1. ????????????????????????????????????????????????????????????; The main entryof mon program?

    ;从这里开始就是正真的代码入口了!
    AREA??? Init,CODE,READONLY???? ;这表明下面的是一个名为Init的代码段

    ENTRY???????????????????????????????????????????? ? ;定义程序的入口(调试用)?

    EXPORT __ENTRY??????????????????????? ?;导出符号_ENTRY,
    告知 __ENTRY 不

??????????????????????????是在本源文件中,是在别的中定义???????????????????????? 的 在本源文件中要用到

__ENTRY
ResetEntry?

?

?

?


;1)The code,which converts to Big-endian,should be in little endian code.
;2)The following little endian code will be compiled in Big-Endian mode.
;? The code byte order should be changed as the memory bus width.
;3)The pseudo instruction,DCD can not be used here because the linker generates error.

?
?

????????? ;条件编译,在编译成机器码前就设定好
?ASSERT :DEF:ENDIAN_CHANGE
[????? ???????? ENDIAN_CHANGE????????????

????? ;下面是大小端的一个判断,在Option.inc里已经设?FALSE?
ASSERT? :DEF:ENTRY_BUS_WIDTH??????? ;判断ENTRY_BUS_WIDTH是否已定义

[????????? ENTRY_BUS_WIDTH=32????????;如果已经定义了ENTRY_BUS_WIDTH,则判断是不是为32

b ChangeBigEndian????????????????? ?;DCD 0xea000007

?????????????? ;在bigendian中,地址为A的字单元包括字节单元A,A+1,A+2,A+3,字节单元由高位到低位为A,A+1,A+2,A+3
;????地址为A的字单元包括半字单元A,A+2,半字单元由高位到低位为A,A+2

]

[???????? ENTRY_BUS_WIDTH=16?
andeq r14,r7,r0,lsl #20?????????????? ?;DCD 0x0007ea00
]???????????????????????????????????????????????????????????? b?ChangeBigEndian指令,只是由于总线不一样而取 机???????????????????????????????????????????????????????? 器码的顺序不一样

[??????????? ENTRY_BUS_WIDTH=8?
streq r0,[r0,-r10,ror #1]??????????? ?;DCD 0x070000ea
]
|
b ResetHandler ;设成FALSE的话就来到这了,转跳到复位程序入口
]
b HandlerUndef?????????????? ?;转跳到Undefined mode程序入口?0x04
b HandlerSWI?????????????? ;转跳到SWI 中断程序入口 0x08
b HandlerPabort??????????? ;转跳到PAbort(指令异常)程序入口 0x0c
b HandlerDabort??????????? ?;转跳到DAbort(数据异常)程序入口 0x10
b .? ;保留???????????????????????? 0x14
b HandlerIRQ?????????????? ;转跳到IRQ 中断程序入口 0x18
b HandlerFIQ????????????? ;转跳到FIQ 中断程序入口 0x1c

;@0x20
b EnterPWDN??????????? ; Must be @0x20.

;==================================================================================
;下面是改变大小端的程序,这里采用直接定义机器码的方式,至说为什么这么做就得问三星了
;反正我们程序里这段代码也不会去执行,不用去管它
;==================================================================================
ChangeBigEndian???
;@0x24
[ ENTRY_BUS_WIDTH=32
DCD 0xee110f10 ;0xee110f10 => mrc p15,c1,c0,0
DCD 0xe3800080 ;0xe3800080 => orr r0,#0x80;? //Big-endian
DCD 0xee010f10 ;0xee010f10 => mcr p15,0
]
[ ENTRY_BUS_WIDTH=16
DCD 0x0f10ee11
DCD 0x0080e380
DCD 0x0f10ee01
]
[ ENTRY_BUS_WIDTH=8
DCD 0x100f11ee
DCD 0x800080e3
DCD 0x100f01ee
]
DCD 0xffffffff? ;swinv 0xffffff is similar with NOP and run well in both endian mode.
DCD 0xffffffff
DCD 0xffffffff
DCD 0xffffffff
DCD 0xffffffff
b ResetHandler

;=========================================================================================
; Function for entering power down mode
; 1. SDRAM should be in self-refresh mode.
; 2. All interrupt should be maksked for SDRAM/DRAM self-refresh.
; 3. LCD controller should be disabled for SDRAM/DRAM self-refresh.
; 4. The I-cache may have to be turned on.
; 5. The location of the following code may have not to be changed.

;void EnterPWDN(int CLKCON);
EnterPWDN

??ldr? r0,=rCLKCON??
mov r2,r0???????????????????? ;r2=rCLKCON 保存原始数据 0x4c00000c 使能各模块的时钟输入
tst r0,#0x8?????????????????? ;测试bit[3] SLEEP mode? 1=>sleep
bne ENTER_SLEEP??? ?;C=0,即TST结果非0,bit[3]=1

???????????????????????????????????? ;//进入PWDN后如果不是sleep则进入stop

?????????????????????????????????????;//进入Stop mode
ENTER_STOP
?ldr r0,=REFRESH????????? ;0x48000024?? DRAM/SDRAM refresh config
ldr r3,[r0]???????????????????????;r3=rREFRESH
mov r1,r3
orr r1,r1,#BIT_SELFREFRESH??????????????? ?;Enable SDRAM self-refresh
str r1,[r0]???????????????????????????????????????????????? ;Enable SDRAM self-refresh
mov r1,#16???????????????????????????????????????????? ??;wait until self-refresh is issued. may not be needed.
0
subs r1,#1
bne %B0?????????????????????????????????????????????????? ; %B?表示向前找 到 0处
;//wait 16 fclks for self-refresh
ldr r0,=CLKCON??????????????????????????????????????? ;enter STOP mode.
str r2,[r0]

? mov r1,#32
0
subs r1,#1????????????????????????????????????;1) wait until the STOP mode is in effect.
bne %B0????????????????????????????????????????? ;2) Or wait here until the CPU&Peripherals will be turned-off
;Entering SLEEP mode,only the reset by wake-up is available.

?ldr r0,=REFRESH????????????????????????????? ;exit from SDRAM self refresh mode.
str r3,255)">?MOV_PC_LR???????????????????????????????? ?;back to main process

ENTER_SLEEP
;NOTE.
;1) rGSTATUS3 should have the return address after wake-up from SLEEP mode.

?mov r1,#16????????????????????????????? ??;Wait until self-refresh is issued,which may not be needed.
0?
subs r1,#1
bne %B0
;//Wait until self-refresh is issued,which may not be needed

?ldr?r1,=MISCCR????????????????????????? ;IO register
ldr?r0,[r1]
orr?r0,#(7<<17)????????????????????????;Set SCLK0=1,SCLK1=1,SCKE=1.
str?r0,[r1]

?b .??????????????????????????????????????????? ;CPU will die here.
;//进入Sleep Mode,1)设置SDRAM为self-refresh
;//?????? 2)设置MISCCR bit[17] 1:sclk0=sclk 0:sclk0=0
;//???????? bit[18] 1:sclk1=sclk 0:sclk1=0
;//???????? bit[19] 1:Self refresh retain enable
;//?????????? 0:Self refresh retain disable?
;//?????????? When 1,After wake-up from sleep,The self-refresh will be retained.

WAKEUP_SLEEP
;Release SCLKn after wake-up from the SLEEP mode.
ldr?r1,=MISCCR
ldr?r0,[r1]
bic?r0,#(7<<17)????????????? ;SCLK0:0->SCLK,SCLK1:0->SCLK,SCKE:0->=SCKE.
str?r0,[r1]
;//设置MISCCR

????????????????????????????????? ;Set memory control registers
;ldr?r0,=SMRDATA
adrl r0,SMRDATA
ldr?r1,=BWSCON????????????????????? ;BWSCON Address?;//总线宽度和等待控制寄存器
add?r2,#52????????????????????????? ?;End address of SMRDATA
0
ldr?r3,[r0],#4???????????????????????????? ;数据处理后R0自加4,[R0]->R3,R0+4->R0
str?r3,[r1],#4
cmp?r2,r0
bne?%B0
;//设置所有的memory control register,他的初始地址为BWSCON,初始
;//数据在以SMRDATA为起始的存储区

?ldr r1,=GSTATUS3??????????????;GSTATUS3 has the start address just after SLEEP wake-up
ldr r0,255)">?mov pc,r0
;//跳出Sleep Mode,进入Sleep状态前的PC

;如上所说,这里采用HANDLER宏去建立Hander***和Handle***之间的联系
HandlerFIQ????? HANDLER HandleFIQ
HandlerIRQ????? HANDLER HandleIRQ
HandlerUndef??? HANDLER HandleUndef
HandlerSWI????? HANDLER HandleSWI
HandlerDabort?? HANDLER HandleDabort
HandlerPabort?? HANDLER HandlePabort

;===================================================================================
,这一段程序就是用来进行第二次查表的过程了.
;如果说第一次查表是由硬件来完成的,那这一次查表就是由软件来实现的了.
;为什么要查两次表??
;没有办法,ARM把所有的中断都归纳成一个IRQ中断异常和一个FIRQ中断异常
;第一次查表主要是查出是什么异常,可我们总要知道是这个中断异常中的什么中断;
;===================================================================================
IsrIRQ
sub sp,#4 ;给PC寄存器保留
stmfd sp!,{r8-r9} ;把r8-r9压入栈

ldr r9,=INTOFFSET ;把INTOFFSET的地址装入r9? INTOFFSET是一个内部的寄存器,存着中断的偏移

ldr r9,[r9]? ;把INTOFFSET的值装入r9
ldr r8,=HandleEINT0 ;这就是我们第二个中断向量表的入口的,先装入r8
;===================================================================================
;哈哈,这查表方法够好了吧,r8(入口)+index*4(别望了一条指令是4 bytes的喔),
;这不就是我们要找的那一项了吗.找到了表项,下一步做什么?肯定先装入了!
;==================================================================================?
add r8,r8,r9,lsl #2??????? ?;地址对齐,因为每个中断向量占4个字节,即isr = IvectTable + Offeset * 4

ldr r8,[r8]???????????????????? ;装入中断服务程序的入口
str r8,#8]?????????????? ;把入口也入栈,准备用旧招
ldmfd sp!,{r8-r9,pc}?????? ;施招,弹出栈,哈哈,顺便把r8弹出到PC,O了,跳转成功!


LTORG?? ;声明文字池,因为我们用了ldr伪指令


;==============================================================================
; ENTRY(好了,我们的CPU要在这复位了.)
;==============================================================================
ResetHandler
ldr r0,=WTCON?????? ;1.关看门狗
ldr r1,=0x0???????????????? ;bit[5]: 0 - disable; 1 - enable (reset 默认)

str r1,[r0]

ldr r0,=INTMSK
ldr r1,=0xffffffff? ;2.关中断
str r1,=INTSUBMSK
ldr r1,=0x7fff ;3.关子中断
str r1,[r0]

[ {FALSE}?

??????????????????????????????????????????????? ?;4.得有些表示了,该点点LED灯了,不过被FALSE掉了.?
;rGPFDAT = (rGPFDAT & ~(0xf<<4)) | ((~data & 0xf)<<4);
; Led_Display
ldr r0,=GPFCON
ldr r1,=0x5500
str r1,[r0]
ldr r0,=GPFDAT
ldr r1,=0x10
str r1,[r0]
]

;5.为了减少PLL的lock time,调整LOCKTIME寄存器.
ldr r0,=LOCKTIME
ldr r1,=0xffffff
str r1,[r0]

;6.下面就来设置PLL了,你的板快不快就看这了!!?

;这里介绍一下计算公式
;//Fpllo=(m*Fin)/(p*2^s)
;//m=MDIV+8,p=PDIV+2,s=SDIV
;The proper range of P and M: 1<=P<=62,1<=M<=248

;Fpllo必须大于200Mhz小于600Mhz
;Fpllo*2^s必须小于1.2GHz
;如下面的PLLCON设定中的M_DIV P_DIV S_DIV是取自option.h中
;#elif (MCLK==40000000)
;#define PLL_M (0x48)
;#define PLL_P (0x3)
;#define PLL_S (0x2)
;所以m=MDIV+8=80,p=PDIV+2=5,s=SDIV=2
;硬件使用晶振为10Mhz,即Fin=10Mhz
;Fpllo=80*10/5*2^2=40Mhz?
?[? PLL_ON_START

??? ? ; Added for confirm clock divide. for 2440.
; Setting value Fclk:Hclk:Pclk

ldr r0,=CLKDIVN
ldr r1,=CLKDIV_VAL????????????????????? ; 0=1:1:1,1=1:1:2,2=1:2:2,3=1:2:4,?
str r1,[r0]???????????????????????????????????????; 4=1:4:4,5=1:4:8,6=1:3:3,7=1:3:6.?
;//数据表示分频数

;===============================================================================
;MMU_SetAsyncBusMode 和 MMU_SetFastBusMode 都在4K代码以上,
;如果你想你编译出来的程序能在NAND上运行的话,就不要在这调用这两函数了.
;如果你不要求的话,你就用把.啥事没有.
;为什么是4K,问三星吧,就提供4K的内部SRAM,要是提供400K多好呀.
;好了,好了,4K就4K吧,不能用这两函数,自己写还不行吗,下面的代码这这么来了,
;实现和上面两函数一样的功能.
;===============================================================================
; [ CLKDIV_VAL>1?? ; 意思是 Fclk:Hclk 不是 1:1.
; bl MMU_SetAsyncBusMode
; |
; bl MMU_SetFastBusMode ; default value.
; ]

[ CLKDIV_VAL>1?? ; 意思是 Fclk:Hclk 不是 1:1.?
mrc p15,0
orr r0,#0xc0000000??????????????????????????????? ;R1_nF:OR:R1_iA
mcr p15,0
|
mrc p15,0
bic r0,#0xc0000000????????????????????????????????;R1_iA:OR:R1_nF?
mcr p15,0
]

/****************************************************************************************************************************************************/

上接mini2440开发板中启动代码2440INIT.S分析(1)

;配置 UPLL?
;//Configure UPLL Fin=12.0MHz UFout=48MHz
ldr r0,=UPLLCON
ldr r1,=((U_MDIV<<12)+(U_PDIV<<4)+U_SDIV)??
str r1,[r0]
nop ; Caution: After UPLL setting,at least 7-clocks?
nop ; delay must be inserted for setting hardware be completed.
nop
nop
nop
nop
nop?
;配置 MPLL
;//Configure MPLL Fin=12.0MHz MFout=304.8MHz一定要使最后的频率为16.9344MHz,不然你甭想用USB接口了?
ldr r0,=MPLLCON
ldr r1,=((M_MDIV<<12)+(M_PDIV<<4)+M_SDIV)
str r1,[r0]
? ]

;检查是否从SLEEP模式中恢复
ldr r1,=GSTATUS2
ldr r0,[r1]
tst r0,#0x2
;如果是从SLEEP模式中恢复,转跳到SLEEP_WAKEUP.
bne WAKEUP_SLEEP

EXPORT?? ?StartPointAfterSleepWakeUp?????? ;导出符号StartPointAfterSleepWakeUp
StartPointAfterSleepWakeUp

;===============================================================================
;设置内存控制器等寄存器的值,因为这些寄存器是连续排列的,所以采用如下办法对这些
;寄存器进行连续设置.其中用到了
SMRDATA的数据,这在代码后面有定义
;===============================================================================
? ;ldr r0,=SMRDATA
adrl r0,SMRDATA????????????????? ;be careful!,hzh
ldr r1,=BWSCON???????????????? ?;BWSCON 地址
add r2,#52 ;??????????????????????? SMRDATA数据的结束地址,共有52字节的数据

0
ldr r3,#4
str r3,#4
cmp r2,r0
bne %B0

;================================================================================
;如果 EINT0 产生(这中断就是我们按键产生的),就清除SDRAM,不过好像没人会在这个时候按
;================================================================================
; check if EIN0 button is pressed

ldr r0,=0x0
str r1,=GPFUP
ldr r1,=0xff
str r1,[r0]

ldr r1,=GPFDAT
ldr r0,[r1]
bic r0,#(0x1e<<1)? ; bit clear
tst r0,#0x1
bne %F1?? ;如果没有按,就跳到后面的1标号处



; 这就是清零内存的代码

ldr r0,=0x55aa
str r1,[r0]
; ldr r0,=GPFUP
; ldr r1,=0xff
; str r1,[r0] ;LED=****

mov r1,#0
mov r2,#0
mov r3,#0
mov r4,#0
mov r5,#0
mov r6,#0
mov r7,#0
mov r8,#0

ldr r9,=0x4000000?? ;64MB
ldr r0,=0x30000000
0?
stmia r0!,{r1-r8}
subs r9,#32?
bne %B0

;到这就结束了.

1
bl InitStacks ;初始化堆栈
;bl Led_Test ;又是LED,注掉了

;=======================================================================
; 哈哈,下面又有看头了,这个初始化程序好像被名曰hzh的高手改过
; 能在NOR NAND 还有内存中运行,当然了,在内存中运行最简单了.
; 在NOR NAND中运行的话都要先把自己拷到内存中.
; 此外,还记得上面提到的|Image$$RO$$Base|,|Image$$RO$$Limit|...吗?
; 这就是拷贝的依据了!!!
;=========================================================================
ldr r0,=BWSCON
ldr r0,[r0]
ands r0,#6????????????????????????? ?;OM[1:0] != 0,?从NOR FLash启动或直接在内存运行
bne copy_proc_beg???????????????;不读取NAND FLASH
adr r0,ResetEntry?????????????????????;OM[1:0] == 0,为从NAND FLash启动
cmp r0,#0???????????????????????????????? ?;再比较入口是否为0地址处
;==========================================================================
;如果不是,则表示主板设置了从NAND启动,但这个程序由于其它原因,
;并没有从NAND启动,这种情况最有可能的原因就是用仿真器.
;==========================================================================
bne copy_proc_beg???? ?;这种情况也不读取NAND FLASH.
;nop?????????????????????????????????? ;如果是0才是真正从NAND 启动,因为其4k被复制到0地址??????????????????????????????????????????????????? 开始的stepingstone 内部sram中
; 注意adr得到的是 相对 地址,非绝对地址 == if use Multi-ice,

;===========================================================
nand_boot_beg???????????????????????? ?;这一段代码完成从NAND读代码到RAM
mov r5,#NFCONF??????????????????????? ;首先设定NAND的一些控制寄存器
;set timing value
ldr r0,=(7<<12)|(7<<8)|(7<<4)
str r0,[r5]
;enable control??????????????????
ldr r0,=(0<<13)|(0<<12)|(0<<10)|(0<<9)|(0<<8)|(1<<6)|(1<<5)|(1<<4)|(1<<1)|(1<<0)
str r0,[r5,#4]

bl ReadNandID ;按着读取NAND的ID号,结果保存在r5里
mov r6,#0? ;r6设初值0.
ldr r0,=0xec73 ;期望的NAND ID号
cmp r5,r0 ;这里进行比较
beq %F1? ;相等的话就跳到下一个1标号处
ldr r0,=0xec75 ;这是另一个期望值
cmp r5,r0
beq %F1? ;相等的话就跳到下一个1标号处
mov r6,#1? ;不相等了,设置r6=1.
1?
bl ReadNandStatus???????????????????????????? ;读取NAND状态,结果放在r1里

mov r8,#0????????????????????????????????????????????? ?;r8设初值0,意义为页号
ldr r9,=ResetEntry???????????????????????????????? ;r9设初值为初始化程序入口地址
;=========================================================================
; 注意,在这里使用的是ldr伪指令,而不是上面用的adr伪指令,它加载的是ResetEntry
; 的决对地址,也就是我们期望的RAM中的地址,在这里,它和|Image$$RO$$Base|一样
; 也就是说,我如我们编译程序时RO BASE指定的地址在RAM里,而把生成的文件拷到
; NAND里运行,由ldr加载的r9的值还是定位在内存.
;=========================================================================
2?
ands r0,#0x1f??????????????????????????? ;凡r8为0x1f(32)的整数倍-1,eq有效,ne无效
bne? %F3?????????????????????????????????????????;这句的意思是对每个块(32页)进行检错
mov? r0,r8??????????????????????????????????????? ;r8->r0
bl? CheckBadBlk?????????????????????????????;检查NAND的坏区
cmp? r0,#0?????????????????????????????????????? ;比较r0和0
addne r8,#32 ;存在坏块的话就跳过这个坏块
bne? %F4 ;没有的话就跳到标???? 号4处
3?
mov r0,r8? ;当前页号->r0
mov r1,r9? ;当前目标地址->r1
bl ReadNandPage ;读取该页的NAND数据到RAM
add r9,#512 ;每一页的大小是512Bytes
add r8,#1 ;r8指向下一页
4?
cmp r8,#256???????????????????????????????? ;比较是否读完256页即128KBytes
bcc %B2?????????????????????????????????????? ?;如果r8小于256(没读完),就返回前面的标号2处

mov r5,#NFCONF??????????????????? ?? ;DsNandFlash
ldr r0,#4]
bic r0,#1
str r0,#4]
ldr pc,=copy_proc_beg???????????????????????????? ;调用copy_proc_beg
;===========================================================
copy_proc_beg
adr r0,ResetEntry??????????????????????????? ?;ResetEntry值->r0
ldr r2,BaseOfROM????????????????????????? ;BaseOfROM值(后面有定义)->r2
cmp r0,r2????????????????????????????????????????? ;比较r0和r2
ldreq r0,TopOfROM?????????????????????????;如果相等的话(在内存运行),TopOfROM->r0
beq InitRam???????????????????????????????????? ;同时跳到InitRam

;=========================================================
;下面这个是针对代码在NOR FLASH时的拷贝方法
;功能为把从ResetEntry起,TopOfROM-BaseOfROM大小的数据拷到BaseOfROM
;TopOfROM和BaseOfROM为|Image$$RO$$Limit|和|Image$$RO$$Base|
;|Image$$RO$$Limit|和|Image$$RO$$Base|由连接器生成
;为生成的代码的代码段运行时的起启和终止地址
;BaseOfBSS和BaseOfZero为|Image$$RW$$Base|和|Image$$ZI$$Base|
;|Image$$RW$$Base|和|Image$$ZI$$Base|也是由连接器生成
;两者之间就是初始化数据的存放地放
;=======================================================

ldr r3,TopOfROM?
0
ldmia r0!,{r4-r7}
stmia r2!,{r4-r7}
cmp r2,r3
bcc %B0

sub r2,r2,r3? ;r2=BaseOfROM-TopOfROM=(-)代码长度??
sub r0,r2 ;r0=ResetEntry-(-)代码长度=ResetEntry+代码长度?

InitRam?
ldr r2,BaseOfBSS??????????????????????????? ;BaseOfBSS->r2
ldr r3,BaseOfZero??????????????????????????? ?;BaseOfZero->r3
0
cmp r2,r3????????????????????????? ?;比较BaseOfBSS和BaseOfZero
ldrcc r1,#4? ;要是r21?? ; means Fclk:Hclk is not 1:1.
; bl MMU_SetAsyncBusMode
; |
; bl MMU_SetFastBusMode ; default value.
; ]

;bl Led_Test

;===========================================================
; 进入C语言前的最后一步了,就是把我们用说查二级向量表
; 的中断例程安装到一级向量表(异常向量表)里.
ldr r0,=HandleIRQ?????? ;This routine is needed
ldr r1,=IsrIRQ?? ;if there is not 'subs pc,lr,#4' at 0x18,0x1c
str r1,[r0]

; ;Copy and paste RW data/zero initialized data
; ldr r0,=|Image$$RO$$Limit| ; Get pointer to ROM data
; ldr r1,=|Image$$RW$$Base|? ; and RAM copy
; ldr r3,=|Image$$ZI$$Base|
;
; ;Zero init base => top of initialised data
; cmp r0,r1????? ; Check that they are different
; beq %F2
;1
; cmp r1,r3????? ; Copy init data
; ldrcc r2,#4??? ;--> LDRCC r2,[r0] + ADD r0,#4
; strcc r2,#4??? ;--> STRCC r2,[r1] + ADD r1,#4
; bcc %B1
;2
; ldr r1,=|Image$$ZI$$Limit| ; Top of zero init segment
; mov r2,#0
;3
; cmp r3,r1????? ; Zero init
; strcc r2,[r3],#4
; bcc %B3


;*****************************************************************************
;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
; 妈呀,终说见到艳阳天了!!!!!!!!!!
;?????? 跳到C语言的main函数处了.
;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
;*****************************************************************************
[ :LNOT:THUMBCODE
bl Main ;Do not use main() because ......
;ldr pc,=Main ;hzh
b .
]

[ THUMBCODE? ;for start-up code for Thumb mode
orr lr,pc,#1
bx lr
CODE16
bl Main ;Do not use main() because ......
b .
CODE32
]


; initializing stacks
InitStacks
;Do not use DRAM,such as stmfd,ldmfd......
;SVCstack is initialized before
;Under toolkit ver 2.5,'msr cpsr,r1' can be used instead of 'msr cpsr_cxsf,r1'
mrs r0,cpsr
bic r0,#MODEMASK
orr r1,#UNDEFMODE|NOINT
msr cpsr_cxsf,r1? ;UndefMode
ldr sp,=UndefStack? ; UndefStack=0x33FF_5C00

orr r1,#ABORTMODE|NOINT
msr cpsr_cxsf,r1? ;AbortMode
ldr sp,=AbortStack? ; AbortStack=0x33FF_6000

orr r1,#IRQMODE|NOINT
msr cpsr_cxsf,r1? ;IRQMode
ldr sp,=IRQStack? ; IRQStack=0x33FF_7000

orr r1,#FIQMODE|NOINT
msr cpsr_cxsf,r1? ;FIQMode
ldr sp,=FIQStack? ; FIQStack=0x33FF_8000

bic r0,#MODEMASK|NOINT
orr r1,#SVCMODE
msr cpsr_cxsf,r1? ;SVCMode
ldr sp,=SVCStack? ; SVCStack=0x33FF_5800

;USER mode has not be initialized.

mov pc,lr
;The LR register will not be valid if the current mode is not SVC mode.

;===========================================================
ReadNandID
mov????? r7,#NFCONF
ldr????? r0,[r7,#4]? ;NFChipEn();
bic????? r0,#2
str????? r0,#4]
mov????? r0,#0x90? ;WrNFCmd(RdIDCMD);
strb???? r0,#8]
mov????? r4,#0?? ;WrNFAddr(0);
strb???? r4,#0xc]
1?????? ;while(NFIsBusy());
ldr????? r0,#0x20]
tst????? r0,#1
beq????? %B1
ldrb???? r0,#0x10] ;id? = RdNFDat()<<8;
mov????? r0,lsl #8
ldrb???? r1,#0x10] ;id |= RdNFDat();
orr????? r5,r0
ldr????? r0,#4]? ;NFChipDs();
orr????? r0,#4]
mov?? pc,lr?

ReadNandStatus
mov?? r7,#0x70? ;WrNFCmd(QUERYCMD);
strb???? r0,#8]?
ldrb???? r1,#0x10] ;r1 = RdNFDat();
ldr????? r0,lr

WaitNandBusy
mov????? r0,#0x70? ;WrNFCmd(QUERYCMD);
mov????? r1,#NFCONF
strb???? r0,[r1,#8]
1?????? ;while(!(RdNFDat()&0x40));?
ldrb???? r0,#0x10]
tst????? r0,#0x40
beq?? %B1
mov????? r0,#0?? ;WrNFCmd(READCMD0);
strb???? r0,#8]
mov????? pc,lr

CheckBadBlk
mov? r7,lr
mov? r5,#NFCONF

bic????? r0,#0x1f ;addr &= ~0x1f;
ldr????? r1,#4]? ;NFChipEn()
bic????? r1,#2
str????? r1,#4]

mov????? r1,#0x50? ;WrNFCmd(READCMD2)
strb???? r1,#8]
mov????? r1,#5;6? ;6->5
strb???? r1,#0xc] ;WrNFAddr(5);(6) 6->5
strb???? r0,#0xc] ;WrNFAddr(addr)
mov????? r1,lsr #8 ;WrNFAddr(addr>>8)
strb???? r1,#0xc]
cmp????? r6,#0?? ;if(NandAddr)??
movne??? r0,lsr #16 ;WrNFAddr(addr>>16)
strneb?? r0,#0xc]

; bl? WaitNandBusy ;WaitNFBusy()
;do not use WaitNandBusy,after WaitNandBusy will read part A!
mov r0,#100
1
subs r0,#1
bne %B1
2
ldr r0,#0x20]
tst r0,#1
beq %B2?

ldrb r0,#0x10] ;RdNFDat()
sub? r0,#0xff

mov????? r1,#0?? ;WrNFCmd(READCMD0)
strb???? r1,#8]

ldr????? r1,#4]? ;NFChipDs()
orr????? r1,#4]

mov? pc,r7

ReadNandPage
mov?? r7,lr
mov????? r4,r1
mov????? r5,#NFCONF

ldr????? r1,#4]?

mov????? r1,#8]?
strb???? r1,#0xc] ;WrNFAddr(0)
strb???? r0,#0xc]?
cmp????? r6,#0xc]

ldr????? r0,#4]? ;InitEcc()
orr????? r0,#0x10
str????? r0,#4]

bl?????? WaitNandBusy ;WaitNFBusy()

mov????? r0,#0?? ;for(i=0; i<512; i++)
1
ldrb???? r1,#0x10] ;buf[i] = RdNFDat()
strb???? r1,[r4,r0]
add????? r0,#1
bic????? r0,#0x10000
cmp????? r0,#0x200
bcc????? %B1

ldr????? r0,#4]? ;NFChipDs()
orr????? r0,#4]

mov?? pc,r7

;--------------------LED test
EXPORT Led_Test
Led_Test
mov r0,#0x56000000
mov r1,#0x5500
str r1,#0x50]
0?
mov r1,#0x50
str r1,#0x54]
mov r2,#0x100000
1
subs r2,#1
bne %B1

mov r1,#0xa0
str r1,#0x100000
2
subs r2,#1
bne %B2
b %B0
mov pc,lr

;===========================================================

LTORG

;GCS0->SST39VF1601
;GCS1->16c550
;GCS2->IDE
;GCS3->CS8900
;GCS4->DM9000
;GCS5->CF Card
;GCS6->SDRAM
;GCS7->unused

SMRDATA DATA
; Memory configuration should be optimized for best performance
; The following parameter is not optimized.
; Memory access cycle parameter strategy
; 1) The memory settings is? safe parameters even at HCLK=75Mhz.
; 2) SDRAM refresh period is for HCLK<=75Mhz.

DCD (0+(B1_BWSCON<<4)+(B2_BWSCON<<8)+(B3_BWSCON<<12)+(B4_BWSCON<<16)+(B5_BWSCON<<20)+(B6_BWSCON<<24)+(B7_BWSCON<<28))
DCD ((B0_Tacs<<13)+(B0_Tcos<<11)+(B0_Tacc<<8)+(B0_Tcoh<<6)+(B0_Tah<<4)+(B0_Tacp<<2)+(B0_PMC))?? ;GCS0
DCD ((B1_Tacs<<13)+(B1_Tcos<<11)+(B1_Tacc<<8)+(B1_Tcoh<<6)+(B1_Tah<<4)+(B1_Tacp<<2)+(B1_PMC))?? ;GCS1
DCD ((B2_Tacs<<13)+(B2_Tcos<<11)+(B2_Tacc<<8)+(B2_Tcoh<<6)+(B2_Tah<<4)+(B2_Tacp<<2)+(B2_PMC))?? ;GCS2
DCD ((B3_Tacs<<13)+(B3_Tcos<<11)+(B3_Tacc<<8)+(B3_Tcoh<<6)+(B3_Tah<<4)+(B3_Tacp<<2)+(B3_PMC))?? ;GCS3
DCD ((B4_Tacs<<13)+(B4_Tcos<<11)+(B4_Tacc<<8)+(B4_Tcoh<<6)+(B4_Tah<<4)+(B4_Tacp<<2)+(B4_PMC))?? ;GCS4
DCD ((B5_Tacs<<13)+(B5_Tcos<<11)+(B5_Tacc<<8)+(B5_Tcoh<<6)+(B5_Tah<<4)+(B5_Tacp<<2)+(B5_PMC))?? ;GCS5
DCD ((B6_MT<<15)+(B6_Trcd<<2)+(B6_SCAN))??? ;GCS6
DCD ((B7_MT<<15)+(B7_Trcd<<2)+(B7_SCAN))??? ;GCS7
DCD ((REFEN<<23)+(TREFMD<<22)+(Trp<<20)+(Tsrc<<18)+(Tchr<<16)+REFCNT)

DCD 0x32???? ;SCLK power saving mode,BANKSIZE 128M/128M

DCD 0x30???? ;MRSR6 CL=3clk
DCD 0x30???? ;MRSR7 CL=3clk

BaseOfROM DCD |Image$$RO$$Base|
TopOfROM DCD |Image$$RO$$Limit|
BaseOfBSS DCD |Image$$RW$$Base|
BaseOfZero DCD |Image$$ZI$$Base|
EndOfBSS DCD |Image$$ZI$$Limit|

ALIGN

; for entering power down mode
; 1. SDRAM should be in self-refresh mode.
; 2. All interrupt should be maksked for SDRAM/DRAM self-refresh.
; 3. LCD controller should be disabled for SDRAM/DRAM self-refresh.
; 4. The I-cache may have to be turned on.
; 5. The location of the following code may have not to be changed.

;void EnterPWDN(int CLKCON);
EnterPWDN
mov r2,r0? ;r2=rCLKCON
tst r0,#0x8? ;SLEEP mode?
bne ENTER_SLEEP

ENTER_STOP
ldr r0,=REFRESH
ldr r3,[r0]? ;r3=rREFRESH
mov r1,r3
orr r1,#BIT_SELFREFRESH
str r1,[r0]? ;Enable SDRAM self-refresh

mov r1,#16?? ;wait until self-refresh is issued. may not be needed.
0 subs r1,#1
bne %B0

ldr r0,=CLKCON? ;enter STOP mode.
str r2,[r0]

mov r1,#32
0 subs r1,#1 ;1) wait until the STOP mode is in effect.
bne %B0? ;2) Or wait here until the CPU&Peripherals will be turned-off
;?? Entering SLEEP mode,only the reset by wake-up is available.

ldr r0,=REFRESH ;exit from SDRAM self refresh mode.
str r3,[r0]

MOV_PC_LR

ENTER_SLEEP
;NOTE.
;1) rGSTATUS3 should have the return address after wake-up from SLEEP mode.

ldr r0,=REFRESH
ldr r1,[r0]? ;r1=rREFRESH
orr r1,#16?? ;Wait until self-refresh is issued,which may not be needed.
0 subs r1,#1
bne %B0

ldr r1,=MISCCR
ldr r0,[r1]
orr r0,#(7<<17)? ;Set SCLK0=0,SCLK1=0,SCKE=0.
str r0,[r1]

ldr r0,=CLKCON? ; Enter sleep mode
str r2,[r0]

b .?? ;CPU will die here.


WAKEUP_SLEEP
;Release SCLKn after wake-up from the SLEEP mode.
ldr r1,#(7<<17)? ;SCLK0:0->SCLK,SCKE:0->=SCKE.
str r0,[r1]

;Set memory control registers
ldr r0,=SMRDATA ;be careful!,=BWSCON ;BWSCON Address
add r2,#52 ;
Endaddress of SMRDATA
0
ldr r3,r0
bne %B0

mov r1,#256
0 subs r1,#1 ;1) wait until the SelfRefresh is released.
bne %B0

ldr r1,=GSTATUS3? ;GSTATUS3 has the start address just after SLEEP wake-up
ldr r0,[r1]

mov pc,r0

;=====================================================================
; Clock division test
; Assemble code,because VSYNC time is very short
;=====================================================================
EXPORT CLKDIV124
EXPORT CLKDIV144

CLKDIV124

ldr???? r0,= CLKDIVN
ldr???? r1,= 0x3? ; 0x3 = 1:2:4
str???? r1,[r0]
; wait until clock is stable
nop
nop
nop
nop
nop

ldr???? r0,= REFRESH
ldr???? r1,[r0]
bic? r1,#0xff
bic? r1,#(0x7<<8)
orr? r1,#0x470 ; REFCNT135
str???? r1,[r0]
nop
nop
nop
nop
nop
mov???? pc,lr

CLKDIV144
ldr???? r0,= 0x4? ; 0x4 = 1:4:4
str???? r1,#0x630 ; REFCNT675 - 1520
str???? r1,lr


ALIGN

AREA RamData,DATA,READWRITE

^?? _ISR_STARTADDRESS? ; _ISR_STARTADDRESS=0x33FF_FF00
HandleReset? #?? 4
HandleUndef? #?? 4
HandleSWI? #?? 4
HandlePabort??? #?? 4
HandleDabort??? #?? 4
HandleReserved? #?? 4
HandleIRQ? #?? 4
HandleFIQ? #?? 4

;Do not use the label 'IntVectorTable',
;The value of IntVectorTable is different with theaddress you think it may be. ;IntVectorTable ;@0x33FF_FF20 HandleEINT0? #?? 4 HandleEINT1? #?? 4 HandleEINT2? #?? 4 HandleEINT3? #?? 4 HandleEINT4_7 #?? 4 HandleEINT8_23 #?? 4 HandleCAM? #?? 4? ; Added for 2440. HandleBATFLT #?? 4 HandleTICK? #?? 4 HandleWDT? #?? 4 HandleTIMER0? #?? 4 HandleTIMER1? #?? 4 HandleTIMER2? #?? 4 HandleTIMER3? #?? 4 HandleTIMER4? #?? 4 HandleUART2?? #?? 4 ;@0x33FF_FF60 HandleLCD?? #?? 4 HandleDMA0? #?? 4 HandleDMA1? #?? 4 HandleDMA2? #?? 4 HandleDMA3? #?? 4 HandleMMC? #?? 4 HandleSPI0? #?? 4 HandleUART1? #?? 4 HandleNFCON? #?? 4? ; Added for 2440. HandleUSBD? #?? 4 HandleUSBH? #?? 4 HandleIIC? #?? 4 HandleUART0? #?? 4 HandleSPI1?? #?? 4 HandleRTC?? #?? 4 HandleADC?? #?? 4 ;@0x33FF_FFA0

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