LXR linux/arch/arm/kernel/suspend.c

   1#include <linux/init.h>
   2
   3#include <asm/pgalloc.h>
   4#include <asm/pgtable.h>
   5#include <asm/memory.h>
   6#include <asm/suspend.h>
   7#include <asm/tlbflush.h>
   8
   9static pgd_t *suspend_pgd;
  10
  11extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
  12extern void cpu_resume_mmu(void);
  13
  14/*
  15 * This is called by __cpu_suspend() to save the state, and do whatever
  16 * flushing is required to ensure that when the CPU goes to sleep we have
  17 * the necessary data available when the caches are not searched.
  18 */
  19void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
  20{
  21        *save_ptr = virt_to_phys(ptr);
  22
  23        /* This must correspond to the LDM in cpu_resume() assembly */
  24        *ptr++ = virt_to_phys(suspend_pgd);
  25        *ptr++ = sp;
  26        *ptr++ = virt_to_phys(cpu_do_resume);
  27
  28        cpu_do_suspend(ptr);
  29
  30        flush_cache_all();
  31        outer_clean_range(*save_ptr, *save_ptr + ptrsz);
  32        outer_clean_range(virt_to_phys(save_ptr),
  33                          virt_to_phys(save_ptr) + sizeof(*save_ptr));
  34}
  35
  36/*
  37 * Hide the first two arguments to __cpu_suspend - these are an implementation
  38 * detail which platform code shouldn't have to know about.
  39 */
  40int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  41{
  42        struct mm_struct *mm = current->active_mm;
  43        int ret;
  44
  45        if (!suspend_pgd)
  46                return -EINVAL;
  47
  48        /*
  49         * Provide a temporary page table with an identity mapping for
  50         * the MMU-enable code, required for resuming.  On successful
  51         * resume (indicated by a zero return code), we need to switch
  52         * back to the correct page tables.
  53         */
  54        ret = __cpu_suspend(arg, fn);
  55        if (ret == 0) {
  56                cpu_switch_mm(mm->pgd, mm);
  57                local_flush_tlb_all();
  58        }
  59
  60        return ret;
  61}
  62
  63static int __init cpu_suspend_init(void)
  64{
  65        suspend_pgd = pgd_alloc(&init_mm);
  66        if (suspend_pgd) {
  67                unsigned long addr = virt_to_phys(cpu_resume_mmu);
  68                identity_mapping_add(suspend_pgd, addr, addr + SECTION_SIZE);
  69        }
  70        return suspend_pgd ? 0 : -ENOMEM;
  71}
  72core_initcall(cpu_suspend_init);
  73