有江湖的地方就会的历史,忘记历史就意味着背叛。每天打打杀杀,如果不小心就会有人在背后给自己来一刀,这就是背叛的滋味。不要忘记历史,这是前人的血的教训。
cpu/s3c64xx/start.S
#include <config.h> #include <version.h> #ifdef CONFIG_ENABLE_MMU #include <asm/proc/domain.h> #endif #include <regs.h> #ifndef CONFIG_ENABLE_MMU #ifndef CFG_PHY_UBOOT_BASE #define CFG_PHY_UBOOT_BASE CFG_UBOOT_BASE #endif #endif /* * ARM处理器为特殊的任务或者专门的功能指定了3个寄存器:r13,r14,r15. * 寄存器r13通常用作堆栈指针(sp),保存当前处理器模式的堆栈的栈顶。 * 寄存器r14又被称为连接寄存器(lr),保存调用子程序的返回地址。 * 寄存器r15是程序计数器(pc),其内容是处理器要取的下一条指令的地址。 * 两个状态寄存器:cpsr和spsr,分别是当前和备份的程序状态寄存器。 */ /* ************************************************************************* * * Jump vector table as in table 3.1 in [1] * ************************************************************************* */ /* * ARM分支指令可以改变程序的执行流程或者调用子程序。这种指令使得一个程序可以使用子程序、if-then-else * 结构及循环。执行流程的改变迫使程序计数器PC指向一个新的地址。 * B{<cond>} lable 跳转 pc=lable * BL{<cond>} lable 带返回的跳转 pc=lable,lr=BL后面的第一条指令地址 * BX{<cond>} Rm 跳转并切换状态 PC = Rm & 0xfffffffe,T=Rm&1 * BLX{<cond>} lable | Rm 带返回的跳转并切换状态 pc = lable, T =1 pc =Rm & 0xfffffffe,T=Rm&1 lr=BLX后面的第一条指令地址 * 地址lable以一个有符号的相对于pc的偏移量保存在指令中,必须被限制在分支指令的约32MB范围内。T对应于cpsr中的Thumb位,如果指令设 * 置了T,那么ARM切换到Thumb状态。 */ /* * ldr属于load-store指令,它用于在存储器和处理器寄存器之间传输数据。load-store指令有三种类型:单寄存器传输指令 * 多寄存器传输指令和交换指令; * 单寄存器传输指令用于把单个的数据传入或者传出一个寄存器。 * ldr/str <cond> {B} Rd, addressing1 其中ldr是把一个字装入一个寄存器: Rd <--mem32[address];str是从一个寄存器保存一个字或者一个字节 Rd -->mem32[address] */ .globl _start _start: b reset /*该部分为处理器的异常处理向量表。*/ ldr pc, _undefined_instruction ldr pc, _software_interrupt ldr pc, _prefetch_abort ldr pc, _data_abort ldr pc, _not_used ldr pc, _irq ldr pc, _fiq /* * 在当前标号_undefined_instruction所在的地址处放入四字节的数据,这个数据就是undefined_instruction标号 * 的地址.意思就是说在当前_undefined_instruction对应的地址中放的是undefined_instruction的地址 */ /* .word伪操作用于分配一段字内存单元(分配的单元都是字对齐的),并用伪操作中的expr初始化。.long和.int作用与之相同。 */ _undefined_instruction: .word undefined_instruction _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 */ .global _end_vect _end_vect: .balignl 16,0xdeadbeef /* ************************************************************************* * * Startup Code (reset vector) * * 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 在/board/config.mk文档中定义, 他定义了代码在运行时所在的地址, _TEXT_BASE中保存了这个地址 */ _TEXT_BASE: .word TEXT_BASE /* * 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. */ _TEXT_PHY_BASE: .word CFG_PHY_UBOOT_BASE .globl _armboot_start/*声明全局标志. 声明的该标号_armboot_start可以被外部使用*/ _armboot_start: .word _start /* * These are defined in the board-specific linker script. */ .globl _bss_start /*预处理标号 目的:让_bss_start指向__bss_start标号所在的地址*/ _bss_start: .word __bss_start /*在当前标号_bss_start所在的地址处放入__bss_start标号的地址*/ .globl _bss_end/*预处理标号 目的:让_bss_end指向_end标号所在的地址*/ _bss_end: .word _end #ifdef CONFIG_USE_IRQ /* IRQ stack memory (calculated at run-time) */ .globl IRQ_STACK_START /*预处理标号 目的:让IRQ_STACK_START指向地址0x0badc0de(这个需要根据硬件更改)*/ 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 */ /* * 复位向量是处理器上电后执行的第一条指令的位置。这条指令使处理器跳转到初始化代码处。 */ /* * 处理器模式决定了哪些寄存器是活动的以及对cpsr的访问权。处理器复位时则进入到管理模式(Supervisor,SVC) */ reset: /* * set the cpu to SVC32 mode */ /* * ARM指令集提供了2条指令,可以直接控制程序状态寄存器(psr)。MRS指令用于把cpsr或者spsr的值传送到一个寄存器。 * MSR与MRS相反,把一个寄存器的内容传送到cpsr或者spsr。这两条指令可用于对cpsr和spsr进行读/写操作。 */ mrs r0,cpsr bic r0,r0,#0x1f /*EC: 模式位清零*//*bic是位清零(Bit Clear)指令,本语句是把r0的Bit[4:0]位清零(由0x1F指示),然后把结果写入r0中。*/ orr r0,r0,#0xd3 /*EC: 工作模式位设置为10011,为管理模式,irq fiq设置为1,屏蔽中断*/ /*orr指令是按位求或,本语句是r0的 Bit7,Bit6,Bit4,Bit1,Bit0 置为1,其它位保持不变。*/ msr cpsr,r0/*把寄存器r0的值传送到cpsr(当前程序状态寄存器)*/ /*执行完上述操作后,cpsr中的 I=1, F=1, T保持不变(默认为0),M[4:0]=10011,意思是禁止IRQ,禁止FIQ,工作在ARM状态,工作在SVC32模式。*/ /* ************************************************************************* * * CPU_init_critical registers * * setup important registers * setup memory timing * ************************************************************************* */ /* * we do sys-critical inits only at reboot, * not when booting from ram! */ cpu_init_crit: /* * flush v4 I/D caches *//*数据处理指令对于存放在寄存器中的数据进行操作。*/ mov r0, #0 /*协处理器指令用于扩展指令集P协处理器指令可用于提供附加的计算能力,有可用于控制包括cache和内存 * 管理的存储子系统。协处理器指令包括数据处理指令,寄存器传输指令及内存传输指令。协处理器指令只用于带 * 有协处理器的ARM内核。 * CDP {<cond>} cp, opcode1, Cd, Cn{,opcode2} 协处理器数据处理 -- 在协处理器内部执行一个数据处理操作 * <MRC/MCR> {<cond>} cp, opcode1, Rd, Cn, Cm{,opcode2} 协处理器寄存器传输 -- 把数据送入/取出协处理器寄存器 * <LDC/STC> {<cod>} cp, Cd, addressing 协处理器内存比较 -- 从协处理器装载/存储一个内存数据块 * 其中:cp域代表协处理器的编号,为p0~P15. opcode域描述要在协处理器中进行的操作。Cn, Cm及Cd描述在协处理器中的寄存器。 * 协处理器15(CP15)是为系统控制预留的,如内存管理,写缓冲控制,cache控制及寄存器识别等。 * MRC p15,0,r10,c0,c0,0 把协处理器15寄存器c0的内容拷贝到r10中,cp15寄存器c0中包含处理器标识,其内容拷贝到通用寄存器r10 */ mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */ mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */ /* * disable MMU stuff and caches */ 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 /* Peri port setup */ ldr r0, =0x70000000 orr r0, r0, #0x13 mcr p15,0,r0,c15,c2,4 @ 256M(0x70000000-0x7fffffff) #ifdef CONFIG_BOOT_ONENAND ldr r0, =0x70000000 @ onenand controller setup orr r0, r0, #0x100000 ldr r1, =0x4000 orr r1, r1, #0xe0 str r1, [r0] #if defined(CONFIG_S3C6410) || defined(CONFIG_S3C6430) orr r0, r0, #300 @ disable watchdog mov r1, #1 str r1, [r0] mov r1, #0x23000000 @ start buffer register orr r1, r1, #0x30000 orr r1, r1, #0xc800 #else mov r1, =0x20000000 @ start buffer register orr r1, r1, #0xc30000 orr r1, r1, #0xc800 #endif sub r0, r1, #0x0400 @ start address1 register ldr r2, [r1, #0x84] @ ecc bypass orr r2, r2, #0x100 str r2, [r1, #0x84] mov r3, #0x0 @ DFS, FBA str r3, [r0, #0x00] str r3, [r0, #0x04] @ select dataram for DDP as 0 mov r4, #0x104 @ interrupt register mov r5, #0x0002 @ FPA, FSA mov r6, #0x0800 @ BSA onenand_bl1_load: str r5, [r0, #0x1c] @ save FPA, FSA orr r6, r6, #0x02 @ BSC str r6, [r1, #0x00] @ save BSA, BSC str r3, [r1, r4] @ clear interrupt str r3, [r1, #0x80] @ write load command mov r7, #0x100 @ need small delay onenand_wait_loop1: subs r7, r7, #0x1 bne onenand_wait_loop1 add r5, r5, #0x2 @ next FPA, FSA sub r6, r6, #0x2 add r6, r6, #0x200 @ next BSA cmp r5, #0x8 bne onenand_bl1_load #endif /* * Go setup Memory and board specific bits prior to relocation. */ bl lowlevel_init /* go setup pll,mux,memory */ /* when we already run in ram, we don't need to relocate U-Boot. * and actually, memory controller must be configured before U-Boot * is running in ram. */ ldr r0, =0xff000fff bic r1, pc, r0 /* r0 <- current base addr of code */ ldr r2, _TEXT_BASE /* r1 <- original base addr in ram */ bic r2, r2, r0 /* r0 <- current base addr of code */ cmp r1, r2 /* compare r0, r1 */ beq after_copy /* r0 == r1 then skip flash copy */ #ifdef CONFIG_BOOT_NOR /* relocate U-Boot to RAM */ adr r0, _start /* r0 <- current position of code */ ldr r1, _TEXT_PHY_BASE /* r1 <- destination */ ldr r2, _armboot_start ldr r3, _bss_start sub r2, r3, r2 /* r2 <- size of armboot */ add r2, r0, r2 /* r2 <- source end address */ nor_copy_loop: ldmia r0!, {r3-r10} /* copy from source address [r0] */ stmia r1!, {r3-r10} /* copy to target address [r1] */ cmp r0, r2 /* until source end addreee [r2] */ ble nor_copy_loop b after_copy #endif #ifdef CONFIG_BOOT_NAND mov r0, #0x1000 bl copy_from_nand #endif #ifdef CONFIG_BOOT_MOVINAND ldr sp, _TEXT_PHY_BASE bl movi_bl2_copy b after_copy #endif #ifdef CONFIG_BOOT_ONENAND ldr sp, =0x50000000 @ temporary stack #ifdef CONFIG_S3C6400 mov r1, =0x20000000 @ start buffer register orr r1, r1, #0xc30000 orr r1, r1, #0xc800 #else mov r1, #0x23000000 @ start buffer register orr r1, r1, #0x30000 orr r1, r1, #0xc800 #endif ldr r2, [r1, #0x84] @ ecc bypass orr r2, r2, #0x100 str r2, [r1, #0x84] sub r0, r1, #0x0400 @ start address1 register str r3, [r0, #0x00] str r3, [r0, #0x04] @ select dataram for DDP as 0 mov r4, #0x104 @ interrupt register mov r6, #0x0c00 @ fixed dataram1 sector number str r6, [r1, #0x00] mov r3, #0x0 @ DFS, FBA mov r5, #0x0000 @ FPA, FSA ldr r9, =CFG_PHY_UBOOT_BASE @ destination onenand_bl2_load: str r3, [r0, #0x00] @ save DFS, FBA str r5, [r0, #0x1c] @ save FPA, FSA mov r7, #0x0 @ clear interrupt str r7, [r1, r4] str r7, [r1, #0x80] @ write load command mov r8, #0x1000 onenand_wait_loop2: subs r8, r8, #0x1 bne onenand_wait_loop2 onenand_wait_int: @ wait INT and RI ldr r7, [r1, r4] mov r8, #0x8000 orr r8, r8, #0x80 tst r7, r8 beq onenand_wait_int mov r7, #0x0 @ clear interrupt str r7, [r1, r4] mov r8, #0xc00 @ source address (dataram1) mov r10, #0x40 @ copy loop count (64 = 2048 / 32) stmia sp, {r0-r7} @ backup onenand_copy_to_ram: ldmia r8!, {r0-r7} stmia r9!, {r0-r7} subs r10, r10, #0x1 bne onenand_copy_to_ram ldmia sp, {r0-r7} @ restore add r5, r5, #0x4 @ next FPA cmp r5, #0x100 @ last FPA? bne onenand_bl2_load /* next block */ mov r5, #0x0 @ reset FPA add r3, r3, #0x1 @ next FBA cmp r3, #0x2 @ last FBA? bne onenand_bl2_load b after_copy #endif #ifdef CONFIG_BOOT_ONENAND_IROM ldr sp, _TEXT_PHY_BASE bl onenand_bl2_copy b after_copy #endif after_copy: ldr r0, =ELFIN_GPIO_BASE ldr r1, =0xC00 str r1, [r0, #GPPDAT_OFFSET] ldr r1, [r0, #GPFPUD_OFFSET] bic r1, r1, #0xc0000000 orr r1, r1, #0x80000000 str r1, [r0, #GPFPUD_OFFSET] ldr r1, [r0, #GPFDAT_OFFSET] orr r1, r1, #0x8000 str r1, [r0, #GPFDAT_OFFSET] ldr r1, [r0, #GPFCON_OFFSET] bic r1, r1, #0xc0000000 orr r1, r1, #0x40000000 str r1, [r0, #GPFCON_OFFSET] #ifdef CONFIG_ENABLE_MMU enable_mmu: /* enable domain access */ ldr r5, =0x0000ffff 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 /* Enable the MMU */ mmu_on: mrc p15, 0, r0, c1, c0, 0 orr r0, r0, #1 /* Set CR_M to enable MMU */ mcr p15, 0, r0, c1, c0, 0 nop nop nop nop #endif skip_hw_init: /* Set up the stack */ stack_setup: #ifdef CONFIG_MEMORY_UPPER_CODE ldr sp, =(CFG_UBOOT_BASE + CFG_UBOOT_SIZE - 0xc) #else ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */ sub r0, r0, #CFG_MALLOC_LEN /* malloc area */ sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo */ #ifdef CONFIG_USE_IRQ sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ) #endif sub sp, r0, #12 /* leave 3 words for abort-stack */ #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... */ add r0, r0, #4 cmp r0, r1 ble clbss_l ldr pc, _start_armboot _start_armboot: .word start_armboot /*c运行环境已经准备好,通过直接跳转代码进入第二阶段*/ #ifdef 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: mov r10, lr /* save return address */ mov r9, r0 /* get ready to call C functions */ ldr sp, _TEXT_PHY_BASE /* setup temp stack pointer */ sub sp, sp, #12 mov fp, #0 /* no previous frame, so fp=0 */ mov r9, #0x1000 bl copy_uboot_to_ram 3: tst r0, #0x0 bne copy_failed ldr r0, =0x0c000000 ldr r1, _TEXT_PHY_BASE 1: ldr r3, [r0], #4 ldr r4, [r1], #4 teq r3, r4 bne compare_failed /* not matched */ subs r9, r9, #4 bne 1b 4: mov lr, r10 /* all is OK */ mov pc, lr 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); */ #ifdef CONFIG_ENABLE_MMU .globl theLastJump theLastJump: mov r9, r0 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 */ 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 #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 /* * 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 /* * 将r0~r12共13个寄存器的数据都转到sp上句空出的空间里面.具体过程是:先将r0中断数据转到sp指向的地 * 址处,然后将sp调整到sp+4位置处,再将r1中的数据转过去,以此类推... */ 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 /* * 将sp所对应的堆栈的数据送到r0~r14个寄存器中,因为lr就是r14. IA:表示先传送,再递增地址 * (4字节递增) ^:这里不涉及R15,所以只是想告诉CPU使用的是用户模式下的寄存器r0~r14 */ 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 */ .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 #ifdef 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 arm1136_cache_flush arm1136_cache_flush: mcr p15, 0, r1, c7, c5, 0 @ invalidate I cache mov pc, lr @ back to caller #if defined(CONFIG_INTEGRATOR) && defined(CONFIG_ARCH_CINTEGRATOR) /* Use the IntegratorCP function from board/integratorcp/platform.S */ #elif defined(CONFIG_S3C64XX) /* 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 */ mov r0, r0 _loop_forever: b _loop_forever rstctl: .word PM_RSTCTRL_WKUP #endif在这一刻,我真的迷惘了,知道了江湖的成份,但是想详细了解江湖还是这么困难。但我知道我已经没有了退路,江湖我会战胜你的!
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