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         u32 *ctx = ptr;
  21
  22         *save_ptr = virt_to_phys(ptr);
  23
  24         /* This must correspond to the LDM in cpu_resume() assembly */
  25         *ptr++ = virt_to_phys(idmap_pgd);
  26         *ptr++ = sp;
  27         *ptr++ = virt_to_phys(cpu_do_resume);
  28
  29         cpu_do_suspend(ptr);
  30
  31         flush_cache_louis();
  32
  33         /*
  34          * flush_cache_louis does not guarantee that
  35          * save_ptr and ptr are cleaned to main memory,
  36          * just up to the Level of Unification Inner Shareable.
  37          * Since the context pointer and context itself
  38          * are to be retrieved with the MMU off that
  39          * data must be cleaned from all cache levels
  40          * to main memory using "area" cache primitives.
  41         */
  42         __cpuc_flush_dcache_area(ctx, ptrsz);
  43         __cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr));
  44
  45         outer_clean_range(*save_ptr, *save_ptr + ptrsz);
  46         outer_clean_range(virt_to_phys(save_ptr),
  47                           virt_to_phys(save_ptr) + sizeof(*save_ptr));
  48 }
  49
  50 /*
  51  * Hide the first two arguments to __cpu_suspend - these are an implementation
  52  * detail which platform code shouldn't have to know about.
  53  */
  54 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  55 {
  56         struct mm_struct *mm = current->active_mm;
  57         int ret;
  58
  59         if (!idmap_pgd)
  60                 return -EINVAL;
  61
  62         /*
  63          * Provide a temporary page table with an identity mapping for
  64          * the MMU-enable code, required for resuming.  On successful
  65          * resume (indicated by a zero return code), we need to switch
  66          * back to the correct page tables.
  67          */
  68         ret = __cpu_suspend(arg, fn);
  69         if (ret == 0) {
  70                 cpu_switch_mm(mm->pgd, mm);
  71                 local_flush_bp_all();
  72                 local_flush_tlb_all();
  73         }
  74
  75         return ret;
  76 }