arch/arm/kernel/suspend.c

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