arch/arm/kernel/suspend.c

   1 #include <linux/init.h>
   2 #include <linux/slab.h>
   3 #include <linux/mm_types.h>
   4
   5 #include <asm/cacheflush.h>
   6 #include <asm/idmap.h>
   7 #include <asm/pgalloc.h>
   8 #include <asm/pgtable.h>
   9 #include <asm/memory.h>
  10 #include <asm/smp_plat.h>
  11 #include <asm/suspend.h>
  12 #include <asm/tlbflush.h>
  13
  14 extern int __cpu_suspend(unsigned long, int (*)(unsigned long), u32 cpuid);
  15 extern void cpu_resume_mmu(void);
  16
  17 #ifdef CONFIG_MMU
  18 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  19 {
  20         struct mm_struct *mm = current->active_mm;
  21         u32 __mpidr = cpu_logical_map(smp_processor_id());
  22         int ret;
  23
  24         if (!idmap_pgd)
  25                 return -EINVAL;
  26
  27         /*
  28          * Provide a temporary page table with an identity mapping for
  29          * the MMU-enable code, required for resuming.  On successful
  30          * resume (indicated by a zero return code), we need to switch
  31          * back to the correct page tables.
  32          */
  33         ret = __cpu_suspend(arg, fn, __mpidr);
  34         if (ret == 0) {
  35                 cpu_switch_mm(mm->pgd, mm);
  36                 local_flush_bp_all();
  37                 local_flush_tlb_all();
  38         }
  39
  40         return ret;
  41 }
  42 #else
  43 int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  44 {
  45         u32 __mpidr = cpu_logical_map(smp_processor_id());
  46         return __cpu_suspend(arg, fn, __mpidr);
  47 }
  48 #define idmap_pgd       NULL
  49 #endif
  50
  51 /*
  52  * This is called by __cpu_suspend() to save the state, and do whatever
  53  * flushing is required to ensure that when the CPU goes to sleep we have
  54  * the necessary data available when the caches are not searched.
  55  */
  56 void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
  57 {
  58         u32 *ctx = ptr;
  59
  60         *save_ptr = virt_to_phys(ptr);
  61
  62         /* This must correspond to the LDM in cpu_resume() assembly */
  63         *ptr++ = virt_to_phys(idmap_pgd);
  64         *ptr++ = sp;
  65         *ptr++ = virt_to_phys(cpu_do_resume);
  66
  67         cpu_do_suspend(ptr);
  68
  69         flush_cache_louis();
  70
  71         /*
  72          * flush_cache_louis does not guarantee that
  73          * save_ptr and ptr are cleaned to main memory,
  74          * just up to the Level of Unification Inner Shareable.
  75          * Since the context pointer and context itself
  76          * are to be retrieved with the MMU off that
  77          * data must be cleaned from all cache levels
  78          * to main memory using "area" cache primitives.
  79         */
  80         __cpuc_flush_dcache_area(ctx, ptrsz);
  81         __cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr));
  82
  83         outer_clean_range(*save_ptr, *save_ptr + ptrsz);
  84         outer_clean_range(virt_to_phys(save_ptr),
  85                           virt_to_phys(save_ptr) + sizeof(*save_ptr));
  86 }
  87
  88 extern struct sleep_save_sp sleep_save_sp;
  89
  90 static int cpu_suspend_alloc_sp(void)
  91 {
  92         void *ctx_ptr;
  93         /* ctx_ptr is an array of physical addresses */
  94         ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(u32), GFP_KERNEL);
  95
  96         if (WARN_ON(!ctx_ptr))
  97                 return -ENOMEM;
  98         sleep_save_sp.save_ptr_stash = ctx_ptr;
  99         sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr);
 100         sync_cache_w(&sleep_save_sp);
 101         return 0;
 102 }
 103 early_initcall(cpu_suspend_alloc_sp);