text: #include <linux/init.h>
  
  #include <asm/idmap.h>
  #include <asm/pgalloc.h>
  #include <asm/pgtable.h>
  #include <asm/memory.h>
  #include <asm/suspend.h>
  #include <asm/tlbflush.h>
  
  extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
  extern void cpu_resume_mmu(void);
  
  /*
   * This is called by __cpu_suspend() to save the state, and do whatever
   * flushing is required to ensure that when the CPU goes to sleep we have
   * the necessary data available when the caches are not searched.
   */
  void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
  {
  	u32 *ctx = ptr;
  
  	*save_ptr = virt_to_phys(ptr);
  
  	/* This must correspond to the LDM in cpu_resume() assembly */
  	*ptr++ = virt_to_phys(idmap_pgd);
  	*ptr++ = sp;
  	*ptr++ = virt_to_phys(cpu_do_resume);
  
  	cpu_do_suspend(ptr);
  
  	flush_cache_louis();
  
  	/*
  	 * flush_cache_louis does not guarantee that
  	 * save_ptr and ptr are cleaned to main memory,
  	 * just up to the Level of Unification Inner Shareable.
  	 * Since the context pointer and context itself
  	 * are to be retrieved with the MMU off that
  	 * data must be cleaned from all cache levels
  	 * to main memory using "area" cache primitives.
  	*/
  	__cpuc_flush_dcache_area(ctx, ptrsz);
  	__cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr));
  
  	outer_clean_range(*save_ptr, *save_ptr + ptrsz);
  	outer_clean_range(virt_to_phys(save_ptr),
  			  virt_to_phys(save_ptr) + sizeof(*save_ptr));
  }
  
  /*
   * Hide the first two arguments to __cpu_suspend - these are an implementation
   * detail which platform code shouldn't have to know about.
   */
  int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
  {
  	struct mm_struct *mm = current->active_mm;
  	int ret;
  
  	if (!idmap_pgd)
  		return -EINVAL;
  
  	/*
  	 * Provide a temporary page table with an identity mapping for
  	 * the MMU-enable code, required for resuming.  On successful
  	 * resume (indicated by a zero return code), we need to switch
  	 * back to the correct page tables.
  	 */
  	ret = __cpu_suspend(arg, fn);
  	if (ret == 0) {
  		cpu_switch_mm(mm->pgd, mm);
  		local_flush_tlb_all();
  	}
  
  	return ret;
  }
  