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
  22 #include "power.h"
  23
  24
  25 extern suspend_disk_method_t pm_disk_mode;
  26
  27 extern int swsusp_suspend(void);
  28 extern int swsusp_write(void);
  29 extern int swsusp_check(void);
  30 extern int swsusp_read(void);
  31 extern void swsusp_close(void);
  32 extern int swsusp_resume(void);
  33
  34
  35 static int noresume = 0;
  36 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  37 dev_t swsusp_resume_device;
  38
  39 /**
  40  *      power_down - Shut machine down for hibernate.
  41  *      @mode:          Suspend-to-disk mode
  42  *
  43  *      Use the platform driver, if configured so, and return gracefully if it
  44  *      fails.
  45  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  46  *      there ain't no turning back.
  47  */
  48
  49 static void power_down(suspend_disk_method_t mode)
  50 {
  51         int error = 0;
  52
  53         switch(mode) {
  54         case PM_DISK_PLATFORM:
  55                 kernel_power_off_prepare();
  56                 error = pm_ops->enter(PM_SUSPEND_DISK);
  57                 break;
  58         case PM_DISK_SHUTDOWN:
  59                 kernel_power_off();
  60                 break;
  61         case PM_DISK_REBOOT:
  62                 kernel_restart(NULL);
  63                 break;
  64         }
  65         kernel_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 }
  71
  72
  73 static int in_suspend __nosavedata = 0;
  74
  75
  76 /**
  77  *      free_some_memory -  Try to free as much memory as possible
  78  *
  79  *      ... but do not OOM-kill anyone
  80  *
  81  *      Notice: all userland should be stopped at this point, or
  82  *      livelock is possible.
  83  */
  84
  85 static void free_some_memory(void)
  86 {
  87         unsigned int i = 0;
  88         unsigned int tmp;
  89         unsigned long pages = 0;
  90         char *p = "-\\|/";
  91
  92         printk("Freeing memory...  ");
  93         while ((tmp = shrink_all_memory(10000))) {
  94                 pages += tmp;
  95                 printk("\b%c", p[i]);
  96                 i++;
  97                 if (i > 3)
  98                         i = 0;
  99         }
 100         printk("\bdone (%li pages freed)\n", pages);
 101 }
 102
 103
 104 static inline void platform_finish(void)
 105 {
 106         if (pm_disk_mode == PM_DISK_PLATFORM) {
 107                 if (pm_ops && pm_ops->finish)
 108                         pm_ops->finish(PM_SUSPEND_DISK);
 109         }
 110 }
 111
 112 static int prepare_processes(void)
 113 {
 114         int error;
 115
 116         pm_prepare_console();
 117         sys_sync();
 118         disable_nonboot_cpus();
 119
 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         return 0;
 135 thaw:
 136         thaw_processes();
 137         enable_nonboot_cpus();
 138         pm_restore_console();
 139         return error;
 140 }
 141
 142 static void unprepare_processes(void)
 143 {
 144         platform_finish();
 145         thaw_processes();
 146         enable_nonboot_cpus();
 147         pm_restore_console();
 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 swsusp to do its 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         error = prepare_processes();
 164         if (error)
 165                 return error;
 166
 167         error = device_suspend(PMSG_FREEZE);
 168         if (error) {
 169                 printk("Some devices failed to suspend\n");
 170                 unprepare_processes();
 171                 return error;
 172         }
 173
 174         pr_debug("PM: snapshotting memory.\n");
 175         in_suspend = 1;
 176         if ((error = swsusp_suspend()))
 177                 goto Done;
 178
 179         if (in_suspend) {
 180                 pr_debug("PM: writing image.\n");
 181                 error = swsusp_write();
 182                 if (!error)
 183                         power_down(pm_disk_mode);
 184                 else {
 185                 /* swsusp_write can not fail in device_resume,
 186                    no need to do second device_resume */
 187                         swsusp_free();
 188                         unprepare_processes();
 189                         return error;
 190                 }
 191         } else
 192                 pr_debug("PM: Image restored successfully.\n");
 193
 194         swsusp_free();
 195  Done:
 196         device_resume();
 197         unprepare_processes();
 198         return error;
 199 }
 200
 201
 202 /**
 203  *      software_resume - Resume from a saved image.
 204  *
 205  *      Called as a late_initcall (so all devices are discovered and
 206  *      initialized), we call swsusp to see if we have a saved image or not.
 207  *      If so, we quiesce devices, the restore the saved image. We will
 208  *      return above (in pm_suspend_disk() ) if everything goes well.
 209  *      Otherwise, we fail gracefully and return to the normally
 210  *      scheduled program.
 211  *
 212  */
 213
 214 static int software_resume(void)
 215 {
 216         int error;
 217
 218         down(&pm_sem);
 219         if (!swsusp_resume_device) {
 220                 if (!strlen(resume_file)) {
 221                         up(&pm_sem);
 222                         return -ENOENT;
 223                 }
 224                 swsusp_resume_device = name_to_dev_t(resume_file);
 225                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 226         } else {
 227                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 228                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 229         }
 230
 231         if (noresume) {
 232                 /**
 233                  * FIXME: If noresume is specified, we need to find the partition
 234                  * and reset it back to normal swap space.
 235                  */
 236                 up(&pm_sem);
 237                 return 0;
 238         }
 239
 240         pr_debug("PM: Checking swsusp image.\n");
 241
 242         if ((error = swsusp_check()))
 243                 goto Done;
 244
 245         pr_debug("PM: Preparing processes for restore.\n");
 246
 247         if ((error = prepare_processes())) {
 248                 swsusp_close();
 249                 goto Done;
 250         }
 251
 252         pr_debug("PM: Reading swsusp image.\n");
 253
 254         if ((error = swsusp_read())) {
 255                 swsusp_free();
 256                 goto Thaw;
 257         }
 258
 259         pr_debug("PM: Preparing devices for restore.\n");
 260
 261         if ((error = device_suspend(PMSG_FREEZE))) {
 262                 printk("Some devices failed to suspend\n");
 263                 swsusp_free();
 264                 goto Thaw;
 265         }
 266
 267         mb();
 268
 269         pr_debug("PM: Restoring saved image.\n");
 270         swsusp_resume();
 271         pr_debug("PM: Restore failed, recovering.n");
 272         device_resume();
 273  Thaw:
 274         unprepare_processes();
 275  Done:
 276         /* For success case, the suspend path will release the lock */
 277         up(&pm_sem);
 278         pr_debug("PM: Resume from disk failed.\n");
 279         return 0;
 280 }
 281
 282 late_initcall(software_resume);
 283
 284
 285 static char * pm_disk_modes[] = {
 286         [PM_DISK_FIRMWARE]      = "firmware",
 287         [PM_DISK_PLATFORM]      = "platform",
 288         [PM_DISK_SHUTDOWN]      = "shutdown",
 289         [PM_DISK_REBOOT]        = "reboot",
 290 };
 291
 292 /**
 293  *      disk - Control suspend-to-disk mode
 294  *
 295  *      Suspend-to-disk can be handled in several ways. The greatest
 296  *      distinction is who writes memory to disk - the firmware or the OS.
 297  *      If the firmware does it, we assume that it also handles suspending
 298  *      the system.
 299  *      If the OS does it, then we have three options for putting the system
 300  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 301  *      powering off the system or rebooting the system (for testing).
 302  *
 303  *      The system will support either 'firmware' or 'platform', and that is
 304  *      known a priori (and encoded in pm_ops). But, the user may choose
 305  *      'shutdown' or 'reboot' as alternatives.
 306  *
 307  *      show() will display what the mode is currently set to.
 308  *      store() will accept one of
 309  *
 310  *      'firmware'
 311  *      'platform'
 312  *      'shutdown'
 313  *      'reboot'
 314  *
 315  *      It will only change to 'firmware' or 'platform' if the system
 316  *      supports it (as determined from pm_ops->pm_disk_mode).
 317  */
 318
 319 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 320 {
 321         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 322 }
 323
 324
 325 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 326 {
 327         int error = 0;
 328         int i;
 329         int len;
 330         char *p;
 331         suspend_disk_method_t mode = 0;
 332
 333         p = memchr(buf, '\n', n);
 334         len = p ? p - buf : n;
 335
 336         down(&pm_sem);
 337         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 338                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 339                         mode = i;
 340                         break;
 341                 }
 342         }
 343         if (mode) {
 344                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 345                         pm_disk_mode = mode;
 346                 else {
 347                         if (pm_ops && pm_ops->enter &&
 348                             (mode == pm_ops->pm_disk_mode))
 349                                 pm_disk_mode = mode;
 350                         else
 351                                 error = -EINVAL;
 352                 }
 353         } else
 354                 error = -EINVAL;
 355
 356         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 357                  pm_disk_modes[mode]);
 358         up(&pm_sem);
 359         return error ? error : n;
 360 }
 361
 362 power_attr(disk);
 363
 364 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 365 {
 366         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 367                        MINOR(swsusp_resume_device));
 368 }
 369
 370 static ssize_t resume_store(struct subsystem * subsys, const char * buf, size_t n)
 371 {
 372         int len;
 373         char *p;
 374         unsigned int maj, min;
 375         int error = -EINVAL;
 376         dev_t res;
 377
 378         p = memchr(buf, '\n', n);
 379         len = p ? p - buf : n;
 380
 381         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
 382                 res = MKDEV(maj,min);
 383                 if (maj == MAJOR(res) && min == MINOR(res)) {
 384                         down(&pm_sem);
 385                         swsusp_resume_device = res;
 386                         up(&pm_sem);
 387                         printk("Attempting manual resume\n");
 388                         noresume = 0;
 389                         software_resume();
 390                 }
 391         }
 392
 393         return error >= 0 ? n : error;
 394 }
 395
 396 power_attr(resume);
 397
 398 static struct attribute * g[] = {
 399         &disk_attr.attr,
 400         &resume_attr.attr,
 401         NULL,
 402 };
 403
 404
 405 static struct attribute_group attr_group = {
 406         .attrs = g,
 407 };
 408
 409
 410 static int __init pm_disk_init(void)
 411 {
 412         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 413 }
 414
 415 core_initcall(pm_disk_init);
 416
 417
 418 static int __init resume_setup(char *str)
 419 {
 420         if (noresume)
 421                 return 1;
 422
 423         strncpy( resume_file, str, 255 );
 424         return 1;
 425 }
 426
 427 static int __init noresume_setup(char *str)
 428 {
 429         noresume = 1;
 430         return 1;
 431 }
 432
 433 __setup("noresume", noresume_setup);
 434 __setup("resume=", resume_setup);