Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 
 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 }
 31 
 32 /**
 33  * acpi_save_state_mem - save kernel state
 34  *
 35  * Create an identity mapped page table and copy the wakeup routine to
 36  * low memory.
 37  */
 38 int acpi_save_state_mem (void)
 39 {
 40         if (!acpi_wakeup_address)
 41                 return 1;
 42         init_low_mapping(swapper_pg_dir, USER_PTRS_PER_PGD);
 43         memcpy((void *) acpi_wakeup_address, &wakeup_start, &wakeup_end - &wakeup_start);
 44         acpi_copy_wakeup_routine(acpi_wakeup_address);
 45 
 46         return 0;
 47 }
 48 
 49 /**
 50  * acpi_save_state_disk - save kernel state to disk
 51  *
 52  */
 53 int acpi_save_state_disk (void)
 54 {
 55         return 1;
 56 }
 57 
 58 /*
 59  * acpi_restore_state - undo effects of acpi_save_state_mem
 60  */
 61 void acpi_restore_state_mem (void)
 62 {
 63         zap_low_mappings();
 64 }
 65 
 66 /**
 67  * acpi_reserve_bootmem - do _very_ early ACPI initialisation
 68  *
 69  * We allocate a page from the first 1MB of memory for the wakeup
 70  * routine for when we come back from a sleep state. The
 71  * runtime allocator allows specification of <16MB pages, but not
 72  * <1MB pages.
 73  */
 74 void __init acpi_reserve_bootmem(void)
 75 {
 76         if ((&wakeup_end - &wakeup_start) > PAGE_SIZE) {
 77                 printk(KERN_ERR "ACPI: Wakeup code way too big, S3 disabled.\n");
 78                 return;
 79         }
 80 
 81         acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);
 82         if (!acpi_wakeup_address)
 83                 printk(KERN_ERR "ACPI: Cannot allocate lowmem, S3 disabled.\n");
 84 }
 85 
 86 static int __init acpi_sleep_setup(char *str)
 87 {
 88         while ((str != NULL) && (*str != '\0')) {
 89                 if (strncmp(str, "s3_bios", 7) == 0)
 90                         acpi_video_flags = 1;
 91                 if (strncmp(str, "s3_mode", 7) == 0)
 92                         acpi_video_flags |= 2;
 93                 str = strchr(str, ',');
 94                 if (str != NULL)
 95                         str += strspn(str, ", \t");
 96         }
 97         return 1;
 98 }
 99 
100 
101 __setup("acpi_sleep=", acpi_sleep_setup);
102 
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