kernel/power/disk.c

   1 /*
   2  * kernel/power/disk.c - Suspend-to-disk support.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2.
   8  *
   9  */
  10
  11 #include <linux/suspend.h>
  12 #include <linux/syscalls.h>
  13 #include <linux/reboot.h>
  14 #include <linux/string.h>
  15 #include <linux/device.h>
  16 #include <linux/delay.h>
  17 #include <linux/fs.h>
  18 #include "power.h"
  19
  20
  21 extern u32 pm_disk_mode;
  22 extern struct pm_ops * pm_ops;
  23
  24 extern int swsusp_suspend(void);
  25 extern int swsusp_write(void);
  26 extern int swsusp_read(void);
  27 extern int swsusp_resume(void);
  28 extern int swsusp_free(void);
  29
  30
  31 static int noresume = 0;
  32 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  33
  34 /**
  35  *      power_down - Shut machine down for hibernate.
  36  *      @mode:          Suspend-to-disk mode
  37  *
  38  *      Use the platform driver, if configured so, and return gracefully if it
  39  *      fails.
  40  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  41  *      there ain't no turning back.
  42  */
  43
  44 static int power_down(u32 mode)
  45 {
  46         unsigned long flags;
  47         int error = 0;
  48
  49         local_irq_save(flags);
  50         switch(mode) {
  51         case PM_DISK_PLATFORM:
  52                 device_power_down(PM_SUSPEND_DISK);
  53                 error = pm_ops->enter(PM_SUSPEND_DISK);
  54                 break;
  55         case PM_DISK_SHUTDOWN:
  56                 printk("Powering off system\n");
  57                 device_shutdown();
  58                 machine_power_off();
  59                 break;
  60         case PM_DISK_REBOOT:
  61                 device_shutdown();
  62                 machine_restart(NULL);
  63                 break;
  64         }
  65         machine_halt();
  66         /* Valid image is on the disk, if we continue we risk serious data corruption
  67            after resume. */
  68         printk(KERN_CRIT "Please power me down manually\n");
  69         while(1);
  70         return 0;
  71 }
  72
  73
  74 static int in_suspend __nosavedata = 0;
  75
  76
  77 /**
  78  *      free_some_memory -  Try to free as much memory as possible
  79  *
  80  *      ... but do not OOM-kill anyone
  81  *
  82  *      Notice: all userland should be stopped at this point, or
  83  *      livelock is possible.
  84  */
  85
  86 static void free_some_memory(void)
  87 {
  88         printk("Freeing memory: ");
  89         while (shrink_all_memory(10000))
  90                 printk(".");
  91         printk("|\n");
  92 }
  93
  94
  95 static inline void platform_finish(void)
  96 {
  97         if (pm_disk_mode == PM_DISK_PLATFORM) {
  98                 if (pm_ops && pm_ops->finish)
  99                         pm_ops->finish(PM_SUSPEND_DISK);
 100         }
 101 }
 102
 103 static void finish(void)
 104 {
 105         device_resume();
 106         platform_finish();
 107         enable_nonboot_cpus();
 108         thaw_processes();
 109         pm_restore_console();
 110 }
 111
 112
 113 static int prepare(void)
 114 {
 115         int error;
 116
 117         pm_prepare_console();
 118
 119         sys_sync();
 120         if (freeze_processes()) {
 121                 error = -EBUSY;
 122                 goto Thaw;
 123         }
 124
 125         if (pm_disk_mode == PM_DISK_PLATFORM) {
 126                 if (pm_ops && pm_ops->prepare) {
 127                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 128                                 goto Thaw;
 129                 }
 130         }
 131
 132         /* Free memory before shutting down devices. */
 133         free_some_memory();
 134
 135         disable_nonboot_cpus();
 136         if ((error = device_suspend(PM_SUSPEND_DISK)))
 137                 goto Finish;
 138
 139         return 0;
 140  Finish:
 141         platform_finish();
 142  Thaw:
 143         enable_nonboot_cpus();
 144         thaw_processes();
 145         pm_restore_console();
 146         return error;
 147 }
 148
 149
 150 /**
 151  *      pm_suspend_disk - The granpappy of power management.
 152  *
 153  *      If we're going through the firmware, then get it over with quickly.
 154  *
 155  *      If not, then call pmdis to do it's thing, then figure out how
 156  *      to power down the system.
 157  */
 158
 159 int pm_suspend_disk(void)
 160 {
 161         int error;
 162
 163         if ((error = prepare()))
 164                 return error;
 165
 166         pr_debug("PM: Attempting to suspend to disk.\n");
 167         if (pm_disk_mode == PM_DISK_FIRMWARE)
 168                 return pm_ops->enter(PM_SUSPEND_DISK);
 169
 170         pr_debug("PM: snapshotting memory.\n");
 171         in_suspend = 1;
 172         if ((error = swsusp_suspend()))
 173                 goto Done;
 174
 175         if (in_suspend) {
 176                 pr_debug("PM: writing image.\n");
 177
 178                 /*
 179                  * FIXME: Leftover from swsusp. Are they necessary?
 180                  */
 181                 mb();
 182                 barrier();
 183
 184                 error = swsusp_write();
 185                 if (!error) {
 186                         error = power_down(pm_disk_mode);
 187                         pr_debug("PM: Power down failed.\n");
 188                 }
 189         } else
 190                 pr_debug("PM: Image restored successfully.\n");
 191         swsusp_free();
 192  Done:
 193         finish();
 194         return error;
 195 }
 196
 197
 198 /**
 199  *      software_resume - Resume from a saved image.
 200  *
 201  *      Called as a late_initcall (so all devices are discovered and
 202  *      initialized), we call pmdisk to see if we have a saved image or not.
 203  *      If so, we quiesce devices, the restore the saved image. We will
 204  *      return above (in pm_suspend_disk() ) if everything goes well.
 205  *      Otherwise, we fail gracefully and return to the normally
 206  *      scheduled program.
 207  *
 208  */
 209
 210 static int software_resume(void)
 211 {
 212         int error;
 213
 214         if (noresume) {
 215                 /**
 216                  * FIXME: If noresume is specified, we need to find the partition
 217                  * and reset it back to normal swap space.
 218                  */
 219                 return 0;
 220         }
 221
 222         pr_debug("PM: Reading pmdisk image.\n");
 223
 224         if ((error = swsusp_read()))
 225                 goto Done;
 226
 227         pr_debug("PM: Preparing system for restore.\n");
 228
 229         if ((error = prepare()))
 230                 goto Free;
 231
 232         barrier();
 233         mb();
 234
 235         pr_debug("PM: Restoring saved image.\n");
 236         swsusp_resume();
 237         pr_debug("PM: Restore failed, recovering.n");
 238         finish();
 239  Free:
 240         swsusp_free();
 241  Done:
 242         pr_debug("PM: Resume from disk failed.\n");
 243         return 0;
 244 }
 245
 246 late_initcall(software_resume);
 247
 248
 249 static char * pm_disk_modes[] = {
 250         [PM_DISK_FIRMWARE]      = "firmware",
 251         [PM_DISK_PLATFORM]      = "platform",
 252         [PM_DISK_SHUTDOWN]      = "shutdown",
 253         [PM_DISK_REBOOT]        = "reboot",
 254 };
 255
 256 /**
 257  *      disk - Control suspend-to-disk mode
 258  *
 259  *      Suspend-to-disk can be handled in several ways. The greatest
 260  *      distinction is who writes memory to disk - the firmware or the OS.
 261  *      If the firmware does it, we assume that it also handles suspending
 262  *      the system.
 263  *      If the OS does it, then we have three options for putting the system
 264  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 265  *      powering off the system or rebooting the system (for testing).
 266  *
 267  *      The system will support either 'firmware' or 'platform', and that is
 268  *      known a priori (and encoded in pm_ops). But, the user may choose
 269  *      'shutdown' or 'reboot' as alternatives.
 270  *
 271  *      show() will display what the mode is currently set to.
 272  *      store() will accept one of
 273  *
 274  *      'firmware'
 275  *      'platform'
 276  *      'shutdown'
 277  *      'reboot'
 278  *
 279  *      It will only change to 'firmware' or 'platform' if the system
 280  *      supports it (as determined from pm_ops->pm_disk_mode).
 281  */
 282
 283 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 284 {
 285         return sprintf(buf,"%s\n",pm_disk_modes[pm_disk_mode]);
 286 }
 287
 288
 289 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 290 {
 291         int error = 0;
 292         int i;
 293         int len;
 294         char *p;
 295         u32 mode = 0;
 296
 297         p = memchr(buf, '\n', n);
 298         len = p ? p - buf : n;
 299
 300         down(&pm_sem);
 301         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 302                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 303                         mode = i;
 304                         break;
 305                 }
 306         }
 307         if (mode) {
 308                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 309                         pm_disk_mode = mode;
 310                 else {
 311                         if (pm_ops && pm_ops->enter &&
 312                             (mode == pm_ops->pm_disk_mode))
 313                                 pm_disk_mode = mode;
 314                         else
 315                                 error = -EINVAL;
 316                 }
 317         } else
 318                 error = -EINVAL;
 319
 320         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 321                  pm_disk_modes[mode]);
 322         up(&pm_sem);
 323         return error ? error : n;
 324 }
 325
 326 power_attr(disk);
 327
 328 static struct attribute * g[] = {
 329         &disk_attr.attr,
 330         NULL,
 331 };
 332
 333
 334 static struct attribute_group attr_group = {
 335         .attrs = g,
 336 };
 337
 338
 339 static int __init pm_disk_init(void)
 340 {
 341         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 342 }
 343
 344 core_initcall(pm_disk_init);
 345
 346
 347 static int __init resume_setup(char *str)
 348 {
 349         if (noresume)
 350                 return 1;
 351
 352         strncpy( resume_file, str, 255 );
 353         return 1;
 354 }
 355
 356 static int __init noresume_setup(char *str)
 357 {
 358         noresume = 1;
 359         return 1;
 360 }
 361
 362 __setup("noresume", noresume_setup);
 363 __setup("resume=", resume_setup);