arch/arm/kernel/suspend.c

   1 #include <linux/init.h>
   2
   3 #include <asm/idmap.h>
   4 #include <asm/pgalloc.h>
   5 #include <asm/pgtable.h>
   6 #include <asm/memory.h>
   7 #include <asm/suspend.h>
   8 #include <asm/tlbflush.h>
   9
  10 extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
  11 extern void cpu_resume_mmu(void);
  12
  13 /*
  14  * This is called by __cpu_suspend() to save the state, and do whatever
  15  * flushing is required to ensure that when the CPU goes to sleep we have
  16  * the necessary data available when the caches are not searched.
  17  */
  18 void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
  19 {
  20         *save_ptr = virt_to_phys(ptr);
  21
  22         /* This must correspond to the LDM in cpu_resume() assembly */
  23         *ptr++ = virt_to_phys(idmap_pgd);
  24         *ptr++ = sp;
  25         *ptr++ = virt_to_phys(cpu_do_resume);
  26
  27         cpu_do_suspend(ptr);
  28
  29         flush_cache_all();
  30         outer_clean_range(*save_ptr, *save_ptr + ptrsz);
  31         outer_clean_range(virt_to_phys(save_ptr),
  32                           virt_to_phys(save_ptr) + sizeof(*save_ptr));
  33 }
  34
  35 /*
  36  * Hide the first two arguments to __cpu_suspend - these are an implementation
  37  * detail which platform code shouldn't have to know about.
  38  */
  39 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  40 {
  41         struct mm_struct *mm = current->active_mm;
  42         int ret;
  43
  44         if (!idmap_pgd)
  45                 return -EINVAL;
  46
  47         /*
  48          * Provide a temporary page table with an identity mapping for
  49          * the MMU-enable code, required for resuming.  On successful
  50          * resume (indicated by a zero return code), we need to switch
  51          * back to the correct page tables.
  52          */
  53         ret = __cpu_suspend(arg, fn);
  54         if (ret == 0) {
  55                 cpu_switch_mm(mm->pgd, mm);
  56                 local_flush_tlb_all();
  57         }
  58
  59         return ret;
  60 }