arch/i386/kernel/acpi/sleep.c

   1 /*
   2  * sleep.c - x86-specific ACPI sleep support.
   3  *
   4  *  Copyright (C) 2001-2003 Patrick Mochel
   5  *  Copyright (C) 2001-2003 Pavel Machek <pavel@suse.cz>
   6  */
   7
   8 #include <linux/acpi.h>
   9 #include <linux/bootmem.h>
  10 #include <asm/smp.h>
  11 #include <asm/tlbflush.h>
  12
  13 /* address in low memory of the wakeup routine. */
  14 unsigned long acpi_wakeup_address = 0;
  15 unsigned long acpi_video_flags;
  16 extern char wakeup_start, wakeup_end;
  17
  18 extern void zap_low_mappings(void);
  19
  20 extern unsigned long FASTCALL(acpi_copy_wakeup_routine(unsigned long));
  21
  22 static void init_low_mapping(pgd_t *pgd, int pgd_limit)
  23 {
  24         int pgd_ofs = 0;
  25
  26         while ((pgd_ofs < pgd_limit) && (pgd_ofs + USER_PTRS_PER_PGD < PTRS_PER_PGD)) {
  27                 set_pgd(pgd, *(pgd+USER_PTRS_PER_PGD));
  28                 pgd_ofs++, pgd++;
  29         }
  30         flush_tlb_all();
  31 }
  32
  33 /**
  34  * acpi_save_state_mem - save kernel state
  35  *
  36  * Create an identity mapped page table and copy the wakeup routine to
  37  * low memory.
  38  */
  39 int acpi_save_state_mem (void)
  40 {
  41         if (!acpi_wakeup_address)
  42                 return 1;
  43         init_low_mapping(swapper_pg_dir, USER_PTRS_PER_PGD);
  44         memcpy((void *) acpi_wakeup_address, &wakeup_start, &wakeup_end - &wakeup_start);
  45         acpi_copy_wakeup_routine(acpi_wakeup_address);
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * acpi_restore_state - undo effects of acpi_save_state_mem
  52  */
  53 void acpi_restore_state_mem (void)
  54 {
  55         zap_low_mappings();
  56 }
  57
  58 /**
  59  * acpi_reserve_bootmem - do _very_ early ACPI initialisation
  60  *
  61  * We allocate a page from the first 1MB of memory for the wakeup
  62  * routine for when we come back from a sleep state. The
  63  * runtime allocator allows specification of <16MB pages, but not
  64  * <1MB pages.
  65  */
  66 void __init acpi_reserve_bootmem(void)
  67 {
  68         if ((&wakeup_end - &wakeup_start) > PAGE_SIZE) {
  69                 printk(KERN_ERR "ACPI: Wakeup code way too big, S3 disabled.\n");
  70                 return;
  71         }
  72
  73         acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);
  74         if (!acpi_wakeup_address)
  75                 printk(KERN_ERR "ACPI: Cannot allocate lowmem, S3 disabled.\n");
  76 }
  77
  78 static int __init acpi_sleep_setup(char *str)
  79 {
  80         while ((str != NULL) && (*str != '\0')) {
  81                 if (strncmp(str, "s3_bios", 7) == 0)
  82                         acpi_video_flags = 1;
  83                 if (strncmp(str, "s3_mode", 7) == 0)
  84                         acpi_video_flags |= 2;
  85                 str = strchr(str, ',');
  86                 if (str != NULL)
  87                         str += strspn(str, ", \t");
  88         }
  89         return 1;
  90 }
  91
  92
  93 __setup("acpi_sleep=", acpi_sleep_setup);