arch/arm/kernel/sleep.S

   1 #include <linux/linkage.h>
   2 #include <asm/asm-offsets.h>
   3 #include <asm/assembler.h>
   4 #include <asm/glue-cache.h>
   5 #include <asm/glue-proc.h>
   6 #include <asm/system.h>
   7         .text
   8
   9 /*
  10  * Save CPU state for a suspend
  11  *  r1 = v:p offset
  12  *  r3 = virtual return function
  13  * Note: sp is decremented to allocate space for CPU state on stack
  14  * r0-r3,r9,r10,lr corrupted
  15  */
  16 ENTRY(cpu_suspend)
  17         mov     r9, lr
  18 #ifdef MULTI_CPU
  19         ldr     r10, =processor
  20         mov     r2, sp                  @ current virtual SP
  21         ldr     r0, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
  22         ldr     ip, [r10, #CPU_DO_RESUME] @ virtual resume function
  23         sub     sp, sp, r0              @ allocate CPU state on stack
  24         mov     r0, sp                  @ save pointer
  25         add     ip, ip, r1              @ convert resume fn to phys
  26         stmfd   sp!, {r1, r2, r3, ip}   @ save v:p, virt SP, retfn, phys resume fn
  27         ldr     r3, =sleep_save_sp
  28         add     r2, sp, r1              @ convert SP to phys
  29         str     r2, [r3]                @ save phys SP
  30         mov     lr, pc
  31         ldr     pc, [r10, #CPU_DO_SUSPEND] @ save CPU state
  32 #else
  33         mov     r2, sp                  @ current virtual SP
  34         ldr     r0, =cpu_suspend_size
  35         sub     sp, sp, r0              @ allocate CPU state on stack
  36         mov     r0, sp                  @ save pointer
  37         stmfd   sp!, {r1, r2, r3}       @ save v:p, virt SP, return fn
  38         ldr     r3, =sleep_save_sp
  39         add     r2, sp, r1              @ convert SP to phys
  40         str     r2, [r3]                @ save phys SP
  41         bl      cpu_do_suspend
  42 #endif
  43
  44         @ flush data cache
  45 #ifdef MULTI_CACHE
  46         ldr     r10, =cpu_cache
  47         mov     lr, r9
  48         ldr     pc, [r10, #CACHE_FLUSH_KERN_ALL]
  49 #else
  50         mov     lr, r9
  51         b       __cpuc_flush_kern_all
  52 #endif
  53 ENDPROC(cpu_suspend)
  54         .ltorg
  55
  56 /*
  57  * r0 = control register value
  58  * r1 = v:p offset (preserved by cpu_do_resume)
  59  * r2 = phys page table base
  60  * r3 = L1 section flags
  61  */
  62 ENTRY(cpu_resume_mmu)
  63         adr     r4, cpu_resume_turn_mmu_on
  64         mov     r4, r4, lsr #20
  65         orr     r3, r3, r4, lsl #20
  66         ldr     r5, [r2, r4, lsl #2]    @ save old mapping
  67         str     r3, [r2, r4, lsl #2]    @ setup 1:1 mapping for mmu code
  68         sub     r2, r2, r1
  69         ldr     r3, =cpu_resume_after_mmu
  70         bic     r1, r0, #CR_C           @ ensure D-cache is disabled
  71         b       cpu_resume_turn_mmu_on
  72 ENDPROC(cpu_resume_mmu)
  73         .ltorg
  74         .align  5
  75 cpu_resume_turn_mmu_on:
  76         mcr     p15, 0, r1, c1, c0, 0   @ turn on MMU, I-cache, etc
  77         mrc     p15, 0, r1, c0, c0, 0   @ read id reg
  78         mov     r1, r1
  79         mov     r1, r1
  80         mov     pc, r3                  @ jump to virtual address
  81 ENDPROC(cpu_resume_turn_mmu_on)
  82 cpu_resume_after_mmu:
  83         str     r5, [r2, r4, lsl #2]    @ restore old mapping
  84         mcr     p15, 0, r0, c1, c0, 0   @ turn on D-cache
  85         mov     pc, lr
  86 ENDPROC(cpu_resume_after_mmu)
  87
  88 /*
  89  * Note: Yes, part of the following code is located into the .data section.
  90  *       This is to allow sleep_save_sp to be accessed with a relative load
  91  *       while we can't rely on any MMU translation.  We could have put
  92  *       sleep_save_sp in the .text section as well, but some setups might
  93  *       insist on it to be truly read-only.
  94  */
  95         .data
  96         .align
  97 ENTRY(cpu_resume)
  98         ldr     r0, sleep_save_sp       @ stack phys addr
  99         msr     cpsr_c, #PSR_I_BIT | PSR_F_BIT | SVC_MODE @ set SVC, irqs off
 100 #ifdef MULTI_CPU
 101         ldmia   r0!, {r1, sp, lr, pc}   @ load v:p, stack, return fn, resume fn
 102 #else
 103         ldmia   r0!, {r1, sp, lr}       @ load v:p, stack, return fn
 104         b       cpu_do_resume
 105 #endif
 106 ENDPROC(cpu_resume)
 107
 108 sleep_save_sp:
 109         .word   0                               @ preserve stack phys ptr here