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五彩晶圆(中级)

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u-boot_smdkv210 分析二:启动代码start.s分析 [复制链接]

u-boot_smdkv210 分析二:启动代码start.s分析

1.链接文件
. = 0x00000000;

. = ALIGN(4);
.text      :
{
  cpu/s5pc11x/start.o    (.text)
  cpu/s5pc11x/s5pc110/cpu_init.o  (.text)

又链接文件可知,首先启动的是start.o,现在从start.s开始分析。

2.启动阶段
u-boot的启动分为两个阶段:
stage1: 系统上电后执行的汇编代码,完成系统初始化、代码搬移等操作。
stage2:搭建c环境,进入c语言执行。


3.start.s

#if defined(CONFIG_EVT1) && !defined(CONFIG_FUSED)    阶段启动相关配置
.word 0x2000
.word 0x0
.word 0x0
.word 0x0
#endif


.globl _start
_start: b reset                                 复位入口,此处使用b指令为相对调整,不依赖运行地址
ldr pc, _undefined_instruction            以下进入异常处理函数
ldr pc, _software_interrupt
ldr pc, _prefetch_abort
ldr pc, _data_abort
ldr pc, _not_used
ldr pc, _irq
ldr pc, _fiq

_undefined_instruction:
.word undefined_instruction                   定义异常处理函数地址
_software_interrupt:
.word software_interrupt
_prefetch_abort:
.word prefetch_abort
_data_abort:
.word data_abort
_not_used:
.word not_used
_irq:
.word irq
_fiq:
.word fiq
_pad:
.word 0x12345678 /* now 16*4=64 */           保证16字节对齐
.global _end_vect
_end_vect:

.balignl 16,0xdeadbeef                       同样是保证16字节对齐,详见.align实验文章
/*
*************************************************************************
*
* Startup Code (reset vector)                       启动代码(复位向量)此处仅进行重要的初始化操作,搬移代码和建立堆栈
*
* do important init only if we don't start from memory!
* setup Memory and board specific bits prior to relocation.
* relocate armboot to ram
* setup stack
*
*************************************************************************
*/

_TEXT_BASE:
.word TEXT_BASE                            TEST_BASE为根目录下Makefile传递进来的参数,具体为0xc3e00000

/*
* Below variable is very important because we use MMU in U-Boot.
* Without it, we cannot run code correctly before MMU is ON.
* by scsuh.                                        下面的代码非常重要,因为我们使用了MMU,没有这段代码,在MMC开启前我们将不能正确的运行代码
*/
_TEXT_PHY_BASE:
.word CFG_PHY_UBOOT_BASE                  由dram的物理地址0x20000000加上0x3e00000而得,即0x23e00000.这个地址为MMU开启前的物理地址

.globl _armboot_start
_armboot_start:
.word _start                                复位地址,具体为0xc3e00010

/*
* These are defined in the board-specific linker script.
*/
.globl _bss_start
_bss_start:
.word __bss_start                           __bss_start在链接脚本文件中的bss段开始,_end在bss段结尾,用于清零bss端,这两个值在链接时才确定

.globl _bss_end
_bss_end:
.word _end

#if defined(CONFIG_USE_IRQ)                         如果使用中断,定义中断栈地址
/* IRQ stack memory (calculated at run-time) */
.globl IRQ_STACK_START
IRQ_STACK_START:
.word 0x0badc0de

/* IRQ stack memory (calculated at run-time) */
.globl FIQ_STACK_START
FIQ_STACK_START:
.word 0x0badc0de
#endif

/*
* the actual reset code
*/

reset:
/*
  * set the cpu to SVC32 mode and IRQ & FIQ disable
  */
@;mrs r0,cpsr
@;bic r0,r0,#0x1f
@;orr r0,r0,#0xd3
@;msr cpsr,r0
msr cpsr_c, #0xd3  @ I & F disable, Mode: 0x13 - SVC  1.进入svc模式,中断禁止


/*
*************************************************************************
*
* CPU_init_critical registers
*
* setup important registers
* setup memory timing
*
*************************************************************************
*/
         /*
         * we do sys-critical inits only at reboot, 仅在关键初始化时执行,而不是在从ram复位时执行
         * not when booting from ram!
         */
cpu_init_crit:

#ifndef CONFIG_EVT1
#if 0
bl v7_flush_dcache_all
#else
bl disable_l2cache                  2.禁止l2cache

mov r0, #0x0 @
mov r1, #0x0 @ i
mov r3, #0x0
mov r4, #0x0
lp1:
mov r2, #0x0 @ j
lp2:
mov r3, r1, LSL #29  @ r3 = r1(i) <<29
mov r4, r2, LSL #6  @ r4 = r2(j) <<6
orr r4, r4, #0x2  @ r3 = (i<<29)|(j<<6)|(1<<1)
orr r3, r3, r4
mov r0, r3   @ r0 = r3
bl CoInvalidateDCacheIndex                        3.清除数据缓存 8 * 1024
add r2, #0x1  @ r2(j)++
cmp r2, #1024  @ r2 < 1024
bne lp2   @ jump to lp2
add r1, #0x1  @ r1(i)++
cmp r1, #8   @ r1(i) < 8
bne lp1   @ jump to lp1

bl set_l2cache_auxctrl                            4.锁定l2cache

bl enable_l2cache                                 5.使能l2cache地址对齐
#endif
#endif

bl disable_l2cache                                6.禁止l2cache

bl set_l2cache_auxctrl_cycle                      7.锁定l2cache

bl enable_l2cache                                 8.使能l2cache

       /*
        * Invalidate L1 I/D
        */
        mov r0, #0                  @ set up for MCR
        mcr p15, 0, r0, c8, c7, 0   @ invalidate TLBs      9.禁止TLB
        mcr p15, 0, r0, c7, c5, 0   @ invalidate icache    10.禁止指令缓存

       /*
        * disable MMU stuff and caches
        */
        mrc p15, 0, r0, c1, c0, 0
        bic r0, r0, #0x00002000     @ clear bits 13 (--V-)
        bic r0, r0, #0x00000007     @ clear bits 2:0 (-CAM)
        orr r0, r0, #0x00000002     @ set bit 1 (--A-) Align
        orr r0, r0, #0x00000800     @ set bit 12 (Z---) BTB
        mcr  p15, 0, r0, c1, c0, 0                         11.禁止MMC和cache


        /* Read booting information */
        ldr r0, =PRO_ID_BASE
        ldr r1, [r0,#OMR_OFFSET]
        bic r2, r1, #0xffffffc1                           12.读取启动信息

#ifdef CONFIG_VOGUES
/* PS_HOLD(GPH0_0) set to output high */
ldr r0, =ELFIN_GPIO_BASE
ldr r1, =0x00000001
str r1, [r0, #GPH0CON_OFFSET]

ldr r1, =0x5500
str r1, [r0, #GPH0PUD_OFFSET]

ldr r1, =0x01
str r1, [r0, #GPH0DAT_OFFSET]
#endif

/* NAND BOOT */
cmp r2, #0x0  @ 512B 4-cycle      13.识别各种启动方式,并将识别到的启动识别码写入R3中
moveq r3, #BOOT_NAND

cmp r2, #0x2  @ 2KB 5-cycle
moveq r3, #BOOT_NAND

cmp r2, #0x4  @ 4KB 5-cycle 8-bit ECC
moveq r3, #BOOT_NAND

cmp r2, #0x6  @ 4KB 5-cycle 16-bit ECC
moveq r3, #BOOT_NAND

cmp r2, #0x8  @ OneNAND Mux
moveq r3, #BOOT_ONENAND

/* SD/MMC BOOT */
cmp     r2, #0xc
moveq   r3, #BOOT_MMCSD

/* NOR BOOT */
cmp     r2, #0x14
moveq   r3, #BOOT_NOR

#if 0 /* Android C110 BSP uses OneNAND booting! */
/* For second device booting */
/* OneNAND BOOTONG failed */
cmp     r2, #0x8
moveq   r3, #BOOT_SEC_DEV
#endif

/* Uart BOOTONG failed */
cmp     r2, #(0x1<<4)
moveq   r3, #BOOT_SEC_DEV

ldr r0, =INF_REG_BASE
str r3, [r0, #INF_REG3_OFFSET]                                 14.将启动标识码写入INF_REG3中

/*
  * Go setup Memory and board specific bits prior to relocation.    15.重定位前初始化存储器和板特殊位
  */

ldr sp, =0xd0036000 /* end of sram dedicated to u-boot */      16.分配给u-boot的sram的结尾 sram为0xd0020000-d003ffff 分配大小为90k
sub sp, sp, #12 /* set stack */
mov fp, #0

bl lowlevel_init /* go setup pll,mux,memory */              17.调用lowlevel_init函数初始化pll memory等与板子相关的内容 函数位于board目录下
/* To hold max8698 output before releasing power on switch,
  * set PS_HOLD signal to high
  */
ldr r0, =0xE010E81C  /* PS_HOLD_CONTROL register */            18.PS_HOLD输出高电平,PS_HOLD使能。PMIC相关
ldr r1, =0x00005301  /* PS_HOLD output high */
str r1, [r0]

/* get ready to call C functions */
ldr sp, _TEXT_PHY_BASE /* setup temp stack pointer */     19.建立临时栈指针,内容为0x23e00000
sub sp, sp, #12
mov fp, #0   /* no previous frame, so fp=0 */

/* when we already run in ram, we don't need to relocate U-Boot.
  * and actually, memory controller must be configured before U-Boot   20.如果程序已经在ram中运行,我们不需要重新定位u-boot。
  * is running in ram.                                                    实际上存储器一定在u-boot在ram中运行前被初始化了
  */
ldr r0, =0xff000fff
bic r1, pc, r0  /* r0 <- current base addr of code */  21.r1=当前PC
ldr r2, _TEXT_BASE  /* r1 <- original base addr in ram */
bic r2, r2, r0  /* r0 <- current base addr of code */  22.r2=定位后运行地址
cmp     r1, r2                  /* compare r0, r1                  */
beq     after_copy  /* r0 == r1 then skip flash copy   */  23.如果r1=r2,跳过复制部分

#if defined(CONFIG_EVT1)
/* If BL1 was copied from SD/MMC CH2 */
ldr r0, =0xD0037488
ldr r1, [r0]                          24.取0xd0037488地址的值
ldr r2, =0xEB200000
cmp r1, r2
beq     mmcsd_boot                        25.如果等于0xEB200000,跳转到mmcsd_boot
#endif

ldr r0, =INF_REG_BASE                 26.读取存储的INF_REG3中的启动类型
ldr r1, [r0, #INF_REG3_OFFSET]
cmp r1, #BOOT_NAND  /* 0x0 => boot device is nand */
beq nand_boot
cmp r1, #BOOT_ONENAND /* 0x1 => boot device is onenand */
beq onenand_boot
cmp     r1, #BOOT_MMCSD
beq     mmcsd_boot
cmp     r1, #BOOT_NOR
beq     nor_boot
cmp     r1, #BOOT_SEC_DEV
beq     mmcsd_boot

nand_boot:
mov r0, #0x1000                       27.以下函数实现代码的搬移
bl copy_from_nand
b after_copy

onenand_boot:
bl onenand_bl2_copy
b after_copy

mmcsd_boot:
#if DELETE
ldr     sp, _TEXT_PHY_BASE      
sub     sp, sp, #12
mov     fp, #0
#endif
bl      movi_bl2_copy
b       after_copy

nor_boot:
bl      read_hword
b       after_copy


after_copy:

#if defined(CONFIG_ENABLE_MMU)
enable_mmu:
/* enable domain access */
ldr r5, =0x0000ffff                 28.定义使能域的访问权限
mcr p15, 0, r5, c3, c0, 0  @load domain access register

/* Set the TTB register */
ldr r0, _mmu_table_base
ldr r1, =CFG_PHY_UBOOT_BASE
ldr r2, =0xfff00000
bic r0, r0, r2
orr r1, r0, r1
mcr p15, 0, r1, c2, c0, 0           29.将MMU启用前的的mmu_table_base转成sdram中的地址,并写入cp15的c2中

/* Enable the MMU */
mmu_on:
mrc p15, 0, r0, c1, c0, 0           30.启用mmu
orr r0, r0, #1
mcr p15, 0, r0, c1, c0, 0
nop
nop
nop
nop
#endif

skip_hw_init:
/* Set up the stack          */
stack_setup:
#if defined(CONFIG_MEMORY_UPPER_CODE)
ldr sp, =(CFG_UBOOT_BASE + CFG_UBOOT_SIZE - 0x1000)
#else
ldr r0, _TEXT_BASE  /* upper 128 KiB: relocated uboot   */      0xc3e00000
sub r0, r0, #CFG_MALLOC_LEN /* malloc area                      */      0x4000
sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo                        */      128
#if defined(CONFIG_USE_IRQ)
sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)                2*4*1024
#endif
sub sp, r0, #12  /* leave 3 words for abort-stack    */      31.为取址终止异常预留3个字空间

#endif

clear_bss:
ldr r0, _bss_start  /* find start of bss segment        */
ldr r1, _bss_end  /* stop here                        */
mov  r2, #0x00000000  /* clear                            */

clbss_l:
str r2, [r0]  /* clear loop...                    */      32.清除bss端内存
add r0, r0, #4
cmp r0, r1
ble clbss_l

ldr pc, _start_armboot                                                  33.第一阶段结束,进入c程序阶段

_start_armboot:
.word start_armboot

#if defined(CONFIG_ENABLE_MMU)
_mmu_table_base:
.word mmu_table
#endif

/*
* copy U-Boot to SDRAM and jump to ram (from NAND or OneNAND)
* r0: size to be compared
* Load 1'st 2blocks to RAM because U-boot's size is larger than 1block(128k) size
*/
.globl copy_from_nand
copy_from_nand:
push {lr}  /* save return address */

mov r9, r0

mov r9, #0x100  /* Compare about 8KB */
bl copy_uboot_to_ram                                 35.从nandflash中读取512k到0x23e00000中
tst  r0, #0x0
bne copy_failed

#if defined(CONFIG_EVT1)
ldr r0, =0xd0020000                                   36.iram的起始地址
#else
ldr r0, =0xd0030000                                   37.iram的中间地址
#endif
ldr r1, _TEXT_PHY_BASE /* 0x23e00000 */

#if !defined(CONFIG_SECURE_BOOT)
1: ldr r3, [r0], #4                                      38.取r0+4地址的值到r3中
ldr r4, [r1], #4                                      39.取r1+4地址的值到r4中
teq r3, r4
bne compare_failed /* not matched */                 40.如果r3和r4不相等,比较失败
subs r9, r9, #4
bne 1b
#endif
pop {pc}  /* all is OK */                   41.复制成功,返回

copy_failed:
nop   /* copy from nand failed */
b copy_failed

compare_failed:
nop   /* compare failed */
b compare_failed

/*
* we assume that cache operation is done before. (eg. cleanup_before_linux())
* actually, we don't need to do anything about cache if not use d-cache in U-Boot
* So, in this function we clean only MMU. by scsuh
*
* void theLastJump(void *kernel, int arch_num, uint boot_params);
*/
#if defined(CONFIG_ENABLE_MMU)
.globl theLastJump
theLastJump:
mov r9, r0                    保存内核地址
ldr r3, =0xfff00000
ldr r4, _TEXT_PHY_BASE
adr r5, phy_last_jump
bic r5, r5, r3
orr r5, r5, r4
mov pc, r5
phy_last_jump:
/*
  * disable MMU stuff             关闭MMU
  */
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #0x00002300 /* clear bits 13, 9:8 (--V- --RS) */
bic r0, r0, #0x00000087 /* clear bits 7, 2:0 (B--- -CAM) */
orr r0, r0, #0x00000002 /* set bit 2 (A) Align */
orr r0, r0, #0x00001000 /* set bit 12 (I) I-Cache */
mcr p15, 0, r0, c1, c0, 0

mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */

mov r0, #0
mov pc, r9                      跳转到内核地址
#endif
/*
*************************************************************************
*
* Interrupt handling
*
*************************************************************************
*/
@
@ IRQ stack frame.
@
#define S_FRAME_SIZE 72

#define S_OLD_R0 68
#define S_PSR  64
#define S_PC  60
#define S_LR  56
#define S_SP  52

#define S_IP  48
#define S_FP  44
#define S_R10  40
#define S_R9  36
#define S_R8  32
#define S_R7  28
#define S_R6  24
#define S_R5  20
#define S_R4  16
#define S_R3  12
#define S_R2  8
#define S_R1  4
#define S_R0  0

#define MODE_SVC 0x13
#define I_BIT  0x80

/*                                                     定义异常时保存寄存器的宏
* use bad_save_user_regs for abort/prefetch/undef/swi ...
* use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
*/

.macro bad_save_user_regs
sub sp, sp, #S_FRAME_SIZE  @ carve out a frame on current user stack
stmia sp, {r0 - r12}   @ Save user registers (now in svc mode) r0-r12

ldr r2, _armboot_start
sub r2, r2, #(CFG_MALLOC_LEN)
sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
ldmia r2, {r2 - r3}   @ get values for "aborted" pc and cpsr (into parm regs)
add r0, sp, #S_FRAME_SIZE  @ grab pointer to old stack

add r5, sp, #S_SP
mov r1, lr
stmia r5, {r0 - r3}   @ save sp_SVC, lr_SVC, pc, cpsr
mov r0, sp    @ save current stack into r0 (param register)
.endm

.macro irq_save_user_regs
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12}   @ Calling r0-r12
add r8, sp, #S_PC   @ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
stmdb r8, {sp, lr}^   @ Calling SP, LR
str lr, [r8, #0]   @ Save calling PC
mrs r6, spsr
str r6, [r8, #4]   @ Save CPSR
str r0, [r8, #8]   @ Save OLD_R0
mov r0, sp
.endm

.macro irq_restore_user_regs
ldmia sp, {r0 - lr}^   @ Calling r0 - lr
mov r0, r0
ldr lr, [sp, #S_PC]   @ Get PC
add sp, sp, #S_FRAME_SIZE
subs pc, lr, #4   @ return & move spsr_svc into cpsr
.endm

.macro get_bad_stack
ldr r13, _armboot_start  @ setup our mode stack (enter in banked mode)
sub r13, r13, #(CFG_MALLOC_LEN) @ move past malloc pool
sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ move to reserved a couple spots for abort stack

str lr, [r13]   @ save caller lr in position 0 of saved stack
mrs lr, spsr   @ get the spsr
str lr, [r13, #4]   @ save spsr in position 1 of saved stack

mov r13, #MODE_SVC   @ prepare SVC-Mode
@ msr spsr_c, r13
msr spsr, r13   @ switch modes, make sure moves will execute
mov lr, pc    @ capture return pc
movs pc, lr    @ jump to next instruction & switch modes.
.endm

.macro get_bad_stack_swi
sub r13, r13, #4   @ space on current stack for scratch reg.
str r0, [r13]   @ save R0's value.
ldr r0, _armboot_start  @ get data regions start
sub r0, r0, #(CFG_MALLOC_LEN) @ move past malloc pool
sub r0, r0, #(CFG_GBL_DATA_SIZE+8) @ move past gbl and a couple spots for abort stack
str lr, [r0]   @ save caller lr in position 0 of saved stack
mrs r0, spsr   @ get the spsr
str lr, [r0, #4]   @ save spsr in position 1 of saved stack
ldr r0, [r13]   @ restore r0
add r13, r13, #4   @ pop stack entry
.endm

.macro get_irq_stack   @ setup IRQ stack
ldr sp, IRQ_STACK_START
.endm

.macro get_fiq_stack   @ setup FIQ stack
ldr sp, FIQ_STACK_START
.endm

/*
* exception handlers                         异常处理句柄
*/
.align 5
undefined_instruction:
get_bad_stack
bad_save_user_regs
bl do_undefined_instruction

.align 5
software_interrupt:
get_bad_stack_swi
bad_save_user_regs
bl do_software_interrupt

.align 5
prefetch_abort:
get_bad_stack
bad_save_user_regs
bl do_prefetch_abort

.align 5
data_abort:
get_bad_stack
bad_save_user_regs
bl do_data_abort

.align 5
not_used:
get_bad_stack
bad_save_user_regs
bl do_not_used

#if defined(CONFIG_USE_IRQ)

.align 5
irq:
get_irq_stack
irq_save_user_regs
bl do_irq
irq_restore_user_regs

.align 5
fiq:
get_fiq_stack
/* someone ought to write a more effiction fiq_save_user_regs */
irq_save_user_regs
bl do_fiq
irq_restore_user_regs

#else

.align 5
irq:
get_bad_stack
bad_save_user_regs
bl do_irq

.align 5
fiq:
get_bad_stack
bad_save_user_regs
bl do_fiq

#endif
.align 5
.global arm_cache_flush
arm_cache_flush:
       mcr     p15, 0, r1, c7, c5, 0           @ invalidate I cache
       mov     pc, lr                          @ back to caller

/*
*     v7_flush_dcache_all()
*
*     Flush the whole D-cache.
*
*     Corrupted registers: r0-r5, r7, r9-r11
*
*     - mm    - mm_struct describing address space
*/
       .align 5
.global v7_flush_dcache_all
v7_flush_dcache_all:

ldr r0, =0xffffffff
mrc p15, 1, r0, c0, c0, 1   @ Read CLIDR
ands r3, r0, #0x7000000
mov r3, r3, LSR #23         @ Cache level value (naturally aligned)
beq  Finished
mov r10, #0
Loop1:         
add r2, r10, r10, LSR #1    @ Work out 3xcachelevel
mov r1, r0, LSR r2          @ bottom 3 bits are the Ctype for this level
and r1, r1, #7              @ get those 3 bits alone
cmp r1, #2
blt Skip                     @ no cache or only instruction cache at this level
mcr p15, 2, r10, c0, c0, 0   @ write the Cache Size selection register
mov r1, #0
mcr p15, 0, r1, c7, c5, 4   @ PrefetchFlush to sync the change to the CacheSizeID reg
mrc p15, 1, r1, c0, c0, 0   @ reads current Cache Size ID register
and r2, r1, #0x7             @ extract the line length field
add r2, r2, #4              @ add 4 for the line length offset (log2 16 bytes)
ldr r4, =0x3FF
ands r4, r4, r1, LSR #3     @ R4 is the max number on the way size (right aligned)
clz r5, r4                  @ R5 is the bit position of the way size increment
ldr r7, =0x00007FFF
ands r7, r7, r1, LSR #13    @ R7 is the max number of the index size (right aligned)
Loop2:         
mov r9, r4                       @ R9 working copy of the max way size (right aligned)
Loop3:         
orr r11, r10, r9, LSL r5         @ factor in the way number and cache number into R11
orr r11, r11, r7, LSL r2         @ factor in the index number
mcr p15, 0, r11, c7, c6, 2   @ invalidate by set/way
subs r9, r9, #1                  @ decrement the way number
bge Loop3
subs r7, r7, #1                  @ decrement the index
bge Loop2
Skip:         
add r10, r10, #2                 @ increment the cache number
cmp r3, r10
bgt Loop1
Finished:
mov pc, lr

       .align  5
.global disable_l2cache
disable_l2cache:
mrc     p15, 0, r0, c1, c0, 1
bic     r0, r0, #(1<<1)
mcr     p15, 0, r0, c1, c0, 1
mov pc, lr


       .align  5
.global enable_l2cache
enable_l2cache:
mrc     p15, 0, r0, c1, c0, 1
orr     r0, r0, #(1<<1)
mcr     p15, 0, r0, c1, c0, 1
mov     pc, lr

       .align  5
.global set_l2cache_auxctrl
set_l2cache_auxctrl:
mov r0, #0x0
mcr     p15, 1, r0, c9, c0, 2
mov     pc, lr

       .align  5
.global set_l2cache_auxctrl_cycle
set_l2cache_auxctrl_cycle:
mrc  p15, 1, r0, c9, c0, 2                   值0010_0000_0010_0000_0001_1100_0111?
bic  r0, r0, #(0x1<<29)
bic  r0, r0, #(0x1<<21)
bic  r0, r0, #(0x7<<6)
bic  r0, r0, #(0x7<<0)
mcr  p15, 1, r0, c9, c0, 2
mov     pc,lr

.align 5
CoInvalidateDCacheIndex:
;/* r0 = index */
mcr     p15, 0, r0, c7, c6, 2
mov     pc,lr


#if defined(CONFIG_INTEGRATOR) && defined(CONFIG_ARCH_CINTEGRATOR)
/* Use the IntegratorCP function from board/integratorcp/platform.S */
#elif defined(CONFIG_S5PC11X)
/* For future usage of S3C64XX*/
#else
.align 5
.globl reset_cpu
reset_cpu:
ldr r1, rstctl /* get addr for global reset reg */
mov r3, #0x2 /* full reset pll+mpu */
str r3, [r1] /* force reset */              复位CPU
mov r0, r0
_loop_forever:
b _loop_forever
rstctl:
.word PM_RSTCTRL_WKUP

#endif


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