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  * Copyright (c) 2004 Pavel Machek <pavel@suse.cz>
   7  *
   8  * This file is released under the GPLv2.
   9  *
  10  */
  11
  12 #include <linux/suspend.h>
  13 #include <linux/syscalls.h>
  14 #include <linux/reboot.h>
  15 #include <linux/string.h>
  16 #include <linux/device.h>
  17 #include <linux/delay.h>
  18 #include <linux/fs.h>
  19 #include <linux/mount.h>
  20 #include <linux/pm.h>
  21 #include <linux/console.h>
  22 #include <linux/cpu.h>
  23
  24 #include "power.h"
  25
  26
  27 static int noresume = 0;
  28 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  29 dev_t swsusp_resume_device;
  30
  31 /**
  32  *      power_down - Shut machine down for hibernate.
  33  *      @mode:          Suspend-to-disk mode
  34  *
  35  *      Use the platform driver, if configured so, and return gracefully if it
  36  *      fails.
  37  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  38  *      there ain't no turning back.
  39  */
  40
  41 static void power_down(suspend_disk_method_t mode)
  42 {
  43         int error = 0;
  44
  45         switch(mode) {
  46         case PM_DISK_PLATFORM:
  47                 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
  48                 error = pm_ops->enter(PM_SUSPEND_DISK);
  49                 break;
  50         case PM_DISK_SHUTDOWN:
  51                 kernel_power_off();
  52                 break;
  53         case PM_DISK_REBOOT:
  54                 kernel_restart(NULL);
  55                 break;
  56         }
  57         kernel_halt();
  58         /* Valid image is on the disk, if we continue we risk serious data corruption
  59            after resume. */
  60         printk(KERN_CRIT "Please power me down manually\n");
  61         while(1);
  62 }
  63
  64 static inline void platform_finish(void)
  65 {
  66         if (pm_disk_mode == PM_DISK_PLATFORM) {
  67                 if (pm_ops && pm_ops->finish)
  68                         pm_ops->finish(PM_SUSPEND_DISK);
  69         }
  70 }
  71
  72 static int prepare_processes(void)
  73 {
  74         int error;
  75
  76         pm_prepare_console();
  77
  78         error = disable_nonboot_cpus();
  79         if (error)
  80                 goto enable_cpus;
  81
  82         if (freeze_processes()) {
  83                 error = -EBUSY;
  84                 goto thaw;
  85         }
  86
  87         /* Free memory before shutting down devices. */
  88         if (!(error = swsusp_shrink_memory()))
  89                 return 0;
  90 thaw:
  91         thaw_processes();
  92 enable_cpus:
  93         enable_nonboot_cpus();
  94         pm_restore_console();
  95         return error;
  96 }
  97
  98 static void unprepare_processes(void)
  99 {
 100         platform_finish();
 101         thaw_processes();
 102         enable_nonboot_cpus();
 103         pm_restore_console();
 104 }
 105
 106 /**
 107  *      pm_suspend_disk - The granpappy of hibernation power management.
 108  *
 109  *      If we're going through the firmware, then get it over with quickly.
 110  *
 111  *      If not, then call swsusp to do its thing, then figure out how
 112  *      to power down the system.
 113  */
 114
 115 int pm_suspend_disk(void)
 116 {
 117         int error;
 118
 119         error = prepare_processes();
 120         if (error)
 121                 return error;
 122
 123         suspend_console();
 124         error = device_suspend(PMSG_FREEZE);
 125         if (error) {
 126                 resume_console();
 127                 printk("Some devices failed to suspend\n");
 128                 unprepare_processes();
 129                 return error;
 130         }
 131
 132         pr_debug("PM: snapshotting memory.\n");
 133         in_suspend = 1;
 134         if ((error = swsusp_suspend()))
 135                 goto Done;
 136
 137         if (in_suspend) {
 138                 device_resume();
 139                 resume_console();
 140                 pr_debug("PM: writing image.\n");
 141                 error = swsusp_write();
 142                 if (!error)
 143                         power_down(pm_disk_mode);
 144                 else {
 145                         swsusp_free();
 146                         unprepare_processes();
 147                         return error;
 148                 }
 149         } else
 150                 pr_debug("PM: Image restored successfully.\n");
 151
 152         swsusp_free();
 153  Done:
 154         device_resume();
 155         resume_console();
 156         unprepare_processes();
 157         return error;
 158 }
 159
 160
 161 /**
 162  *      software_resume - Resume from a saved image.
 163  *
 164  *      Called as a late_initcall (so all devices are discovered and
 165  *      initialized), we call swsusp to see if we have a saved image or not.
 166  *      If so, we quiesce devices, the restore the saved image. We will
 167  *      return above (in pm_suspend_disk() ) if everything goes well.
 168  *      Otherwise, we fail gracefully and return to the normally
 169  *      scheduled program.
 170  *
 171  */
 172
 173 static int software_resume(void)
 174 {
 175         int error;
 176
 177         down(&pm_sem);
 178         if (!swsusp_resume_device) {
 179                 if (!strlen(resume_file)) {
 180                         up(&pm_sem);
 181                         return -ENOENT;
 182                 }
 183                 swsusp_resume_device = name_to_dev_t(resume_file);
 184                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 185         } else {
 186                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 187                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 188         }
 189
 190         if (noresume) {
 191                 /**
 192                  * FIXME: If noresume is specified, we need to find the partition
 193                  * and reset it back to normal swap space.
 194                  */
 195                 up(&pm_sem);
 196                 return 0;
 197         }
 198
 199         pr_debug("PM: Checking swsusp image.\n");
 200
 201         if ((error = swsusp_check()))
 202                 goto Done;
 203
 204         pr_debug("PM: Preparing processes for restore.\n");
 205
 206         if ((error = prepare_processes())) {
 207                 swsusp_close();
 208                 goto Done;
 209         }
 210
 211         pr_debug("PM: Reading swsusp image.\n");
 212
 213         if ((error = swsusp_read())) {
 214                 swsusp_free();
 215                 goto Thaw;
 216         }
 217
 218         pr_debug("PM: Preparing devices for restore.\n");
 219
 220         suspend_console();
 221         if ((error = device_suspend(PMSG_PRETHAW))) {
 222                 resume_console();
 223                 printk("Some devices failed to suspend\n");
 224                 swsusp_free();
 225                 goto Thaw;
 226         }
 227
 228         mb();
 229
 230         pr_debug("PM: Restoring saved image.\n");
 231         swsusp_resume();
 232         pr_debug("PM: Restore failed, recovering.n");
 233         device_resume();
 234         resume_console();
 235  Thaw:
 236         unprepare_processes();
 237  Done:
 238         /* For success case, the suspend path will release the lock */
 239         up(&pm_sem);
 240         pr_debug("PM: Resume from disk failed.\n");
 241         return 0;
 242 }
 243
 244 late_initcall(software_resume);
 245
 246
 247 static const char * const pm_disk_modes[] = {
 248         [PM_DISK_FIRMWARE]      = "firmware",
 249         [PM_DISK_PLATFORM]      = "platform",
 250         [PM_DISK_SHUTDOWN]      = "shutdown",
 251         [PM_DISK_REBOOT]        = "reboot",
 252 };
 253
 254 /**
 255  *      disk - Control suspend-to-disk mode
 256  *
 257  *      Suspend-to-disk can be handled in several ways. The greatest
 258  *      distinction is who writes memory to disk - the firmware or the OS.
 259  *      If the firmware does it, we assume that it also handles suspending
 260  *      the system.
 261  *      If the OS does it, then we have three options for putting the system
 262  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 263  *      powering off the system or rebooting the system (for testing).
 264  *
 265  *      The system will support either 'firmware' or 'platform', and that is
 266  *      known a priori (and encoded in pm_ops). But, the user may choose
 267  *      'shutdown' or 'reboot' as alternatives.
 268  *
 269  *      show() will display what the mode is currently set to.
 270  *      store() will accept one of
 271  *
 272  *      'firmware'
 273  *      'platform'
 274  *      'shutdown'
 275  *      'reboot'
 276  *
 277  *      It will only change to 'firmware' or 'platform' if the system
 278  *      supports it (as determined from pm_ops->pm_disk_mode).
 279  */
 280
 281 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 282 {
 283         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 284 }
 285
 286
 287 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 288 {
 289         int error = 0;
 290         int i;
 291         int len;
 292         char *p;
 293         suspend_disk_method_t mode = 0;
 294
 295         p = memchr(buf, '\n', n);
 296         len = p ? p - buf : n;
 297
 298         down(&pm_sem);
 299         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 300                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 301                         mode = i;
 302                         break;
 303                 }
 304         }
 305         if (mode) {
 306                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 307                         pm_disk_mode = mode;
 308                 else {
 309                         if (pm_ops && pm_ops->enter &&
 310                             (mode == pm_ops->pm_disk_mode))
 311                                 pm_disk_mode = mode;
 312                         else
 313                                 error = -EINVAL;
 314                 }
 315         } else
 316                 error = -EINVAL;
 317
 318         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 319                  pm_disk_modes[mode]);
 320         up(&pm_sem);
 321         return error ? error : n;
 322 }
 323
 324 power_attr(disk);
 325
 326 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 327 {
 328         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 329                        MINOR(swsusp_resume_device));
 330 }
 331
 332 static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
 333 {
 334         unsigned int maj, min;
 335         dev_t res;
 336         int ret = -EINVAL;
 337
 338         if (sscanf(buf, "%u:%u", &maj, &min) != 2)
 339                 goto out;
 340
 341         res = MKDEV(maj,min);
 342         if (maj != MAJOR(res) || min != MINOR(res))
 343                 goto out;
 344
 345         down(&pm_sem);
 346         swsusp_resume_device = res;
 347         up(&pm_sem);
 348         printk("Attempting manual resume\n");
 349         noresume = 0;
 350         software_resume();
 351         ret = n;
 352 out:
 353         return ret;
 354 }
 355
 356 power_attr(resume);
 357
 358 static ssize_t image_size_show(struct subsystem * subsys, char *buf)
 359 {
 360         return sprintf(buf, "%lu\n", image_size);
 361 }
 362
 363 static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
 364 {
 365         unsigned long size;
 366
 367         if (sscanf(buf, "%lu", &size) == 1) {
 368                 image_size = size;
 369                 return n;
 370         }
 371
 372         return -EINVAL;
 373 }
 374
 375 power_attr(image_size);
 376
 377 static struct attribute * g[] = {
 378         &disk_attr.attr,
 379         &resume_attr.attr,
 380         &image_size_attr.attr,
 381         NULL,
 382 };
 383
 384
 385 static struct attribute_group attr_group = {
 386         .attrs = g,
 387 };
 388
 389
 390 static int __init pm_disk_init(void)
 391 {
 392         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 393 }
 394
 395 core_initcall(pm_disk_init);
 396
 397
 398 static int __init resume_setup(char *str)
 399 {
 400         if (noresume)
 401                 return 1;
 402
 403         strncpy( resume_file, str, 255 );
 404         return 1;
 405 }
 406
 407 static int __init noresume_setup(char *str)
 408 {
 409         noresume = 1;
 410         return 1;
 411 }
 412
 413 __setup("noresume", noresume_setup);
 414 __setup("resume=", resume_setup);