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
  21 #include "power.h"
  22
  23
  24 extern suspend_disk_method_t pm_disk_mode;
  25 extern struct pm_ops * pm_ops;
  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 extern int swsusp_free(void);
  34
  35
  36 static int noresume = 0;
  37 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  38 dev_t swsusp_resume_device;
  39
  40 /**
  41  *      power_down - Shut machine down for hibernate.
  42  *      @mode:          Suspend-to-disk mode
  43  *
  44  *      Use the platform driver, if configured so, and return gracefully if it
  45  *      fails.
  46  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  47  *      there ain't no turning back.
  48  */
  49
  50 static void power_down(suspend_disk_method_t mode)
  51 {
  52         unsigned long flags;
  53         int error = 0;
  54
  55         local_irq_save(flags);
  56         switch(mode) {
  57         case PM_DISK_PLATFORM:
  58                 device_shutdown();
  59                 error = pm_ops->enter(PM_SUSPEND_DISK);
  60                 break;
  61         case PM_DISK_SHUTDOWN:
  62                 kernel_power_off();
  63                 break;
  64         case PM_DISK_REBOOT:
  65                 kernel_restart(NULL);
  66                 break;
  67         }
  68         kernel_halt();
  69         /* Valid image is on the disk, if we continue we risk serious data corruption
  70            after resume. */
  71         printk(KERN_CRIT "Please power me down manually\n");
  72         while(1);
  73 }
  74
  75
  76 static int in_suspend __nosavedata = 0;
  77
  78
  79 /**
  80  *      free_some_memory -  Try to free as much memory as possible
  81  *
  82  *      ... but do not OOM-kill anyone
  83  *
  84  *      Notice: all userland should be stopped at this point, or
  85  *      livelock is possible.
  86  */
  87
  88 static void free_some_memory(void)
  89 {
  90         unsigned int i = 0;
  91         unsigned int tmp;
  92         unsigned long pages = 0;
  93         char *p = "-\\|/";
  94
  95         printk("Freeing memory...  ");
  96         while ((tmp = shrink_all_memory(10000))) {
  97                 pages += tmp;
  98                 printk("\b%c", p[i]);
  99                 i++;
 100                 if (i > 3)
 101                         i = 0;
 102         }
 103         printk("\bdone (%li pages freed)\n", pages);
 104 }
 105
 106
 107 static inline void platform_finish(void)
 108 {
 109         if (pm_disk_mode == PM_DISK_PLATFORM) {
 110                 if (pm_ops && pm_ops->finish)
 111                         pm_ops->finish(PM_SUSPEND_DISK);
 112         }
 113 }
 114
 115 static int prepare_processes(void)
 116 {
 117         int error;
 118
 119         pm_prepare_console();
 120         sys_sync();
 121         disable_nonboot_cpus();
 122
 123         if (freeze_processes()) {
 124                 error = -EBUSY;
 125                 goto thaw;
 126         }
 127
 128         if (pm_disk_mode == PM_DISK_PLATFORM) {
 129                 if (pm_ops && pm_ops->prepare) {
 130                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 131                                 goto thaw;
 132                 }
 133         }
 134
 135         /* Free memory before shutting down devices. */
 136         free_some_memory();
 137         return 0;
 138 thaw:
 139         thaw_processes();
 140         enable_nonboot_cpus();
 141         pm_restore_console();
 142         return error;
 143 }
 144
 145 static void unprepare_processes(void)
 146 {
 147         platform_finish();
 148         thaw_processes();
 149         enable_nonboot_cpus();
 150         pm_restore_console();
 151 }
 152
 153 /**
 154  *      pm_suspend_disk - The granpappy of power management.
 155  *
 156  *      If we're going through the firmware, then get it over with quickly.
 157  *
 158  *      If not, then call swsusp to do its thing, then figure out how
 159  *      to power down the system.
 160  */
 161
 162 int pm_suspend_disk(void)
 163 {
 164         int error;
 165
 166         error = prepare_processes();
 167         if (error)
 168                 return error;
 169
 170         error = device_suspend(PMSG_FREEZE);
 171         if (error) {
 172                 printk("Some devices failed to suspend\n");
 173                 unprepare_processes();
 174                 return error;
 175         }
 176
 177         pr_debug("PM: snapshotting memory.\n");
 178         in_suspend = 1;
 179         if ((error = swsusp_suspend()))
 180                 goto Done;
 181
 182         if (in_suspend) {
 183                 pr_debug("PM: writing image.\n");
 184                 error = swsusp_write();
 185                 if (!error)
 186                         power_down(pm_disk_mode);
 187                 else {
 188                 /* swsusp_write can not fail in device_resume,
 189                    no need to do second device_resume */
 190                         swsusp_free();
 191                         unprepare_processes();
 192                         return error;
 193                 }
 194         } else
 195                 pr_debug("PM: Image restored successfully.\n");
 196
 197         swsusp_free();
 198  Done:
 199         device_resume();
 200         unprepare_processes();
 201         return error;
 202 }
 203
 204
 205 /**
 206  *      software_resume - Resume from a saved image.
 207  *
 208  *      Called as a late_initcall (so all devices are discovered and
 209  *      initialized), we call swsusp to see if we have a saved image or not.
 210  *      If so, we quiesce devices, the restore the saved image. We will
 211  *      return above (in pm_suspend_disk() ) if everything goes well.
 212  *      Otherwise, we fail gracefully and return to the normally
 213  *      scheduled program.
 214  *
 215  */
 216
 217 static int software_resume(void)
 218 {
 219         int error;
 220
 221         down(&pm_sem);
 222         if (!swsusp_resume_device) {
 223                 if (!strlen(resume_file)) {
 224                         up(&pm_sem);
 225                         return -ENOENT;
 226                 }
 227                 swsusp_resume_device = name_to_dev_t(resume_file);
 228                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 229         } else {
 230                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 231                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 232         }
 233
 234         if (noresume) {
 235                 /**
 236                  * FIXME: If noresume is specified, we need to find the partition
 237                  * and reset it back to normal swap space.
 238                  */
 239                 up(&pm_sem);
 240                 return 0;
 241         }
 242
 243         pr_debug("PM: Checking swsusp image.\n");
 244
 245         if ((error = swsusp_check()))
 246                 goto Done;
 247
 248         pr_debug("PM: Preparing processes for restore.\n");
 249
 250         if ((error = prepare_processes())) {
 251                 swsusp_close();
 252                 goto Done;
 253         }
 254
 255         pr_debug("PM: Reading swsusp image.\n");
 256
 257         if ((error = swsusp_read()))
 258                 goto Cleanup;
 259
 260         pr_debug("PM: Preparing devices for restore.\n");
 261
 262         if ((error = device_suspend(PMSG_FREEZE))) {
 263                 printk("Some devices failed to suspend\n");
 264                 goto Free;
 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  Free:
 274         swsusp_free();
 275  Cleanup:
 276         unprepare_processes();
 277  Done:
 278         /* For success case, the suspend path will release the lock */
 279         up(&pm_sem);
 280         pr_debug("PM: Resume from disk failed.\n");
 281         return 0;
 282 }
 283
 284 late_initcall(software_resume);
 285
 286
 287 static char * pm_disk_modes[] = {
 288         [PM_DISK_FIRMWARE]      = "firmware",
 289         [PM_DISK_PLATFORM]      = "platform",
 290         [PM_DISK_SHUTDOWN]      = "shutdown",
 291         [PM_DISK_REBOOT]        = "reboot",
 292 };
 293
 294 /**
 295  *      disk - Control suspend-to-disk mode
 296  *
 297  *      Suspend-to-disk can be handled in several ways. The greatest
 298  *      distinction is who writes memory to disk - the firmware or the OS.
 299  *      If the firmware does it, we assume that it also handles suspending
 300  *      the system.
 301  *      If the OS does it, then we have three options for putting the system
 302  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 303  *      powering off the system or rebooting the system (for testing).
 304  *
 305  *      The system will support either 'firmware' or 'platform', and that is
 306  *      known a priori (and encoded in pm_ops). But, the user may choose
 307  *      'shutdown' or 'reboot' as alternatives.
 308  *
 309  *      show() will display what the mode is currently set to.
 310  *      store() will accept one of
 311  *
 312  *      'firmware'
 313  *      'platform'
 314  *      'shutdown'
 315  *      'reboot'
 316  *
 317  *      It will only change to 'firmware' or 'platform' if the system
 318  *      supports it (as determined from pm_ops->pm_disk_mode).
 319  */
 320
 321 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 322 {
 323         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 324 }
 325
 326
 327 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 328 {
 329         int error = 0;
 330         int i;
 331         int len;
 332         char *p;
 333         suspend_disk_method_t mode = 0;
 334
 335         p = memchr(buf, '\n', n);
 336         len = p ? p - buf : n;
 337
 338         down(&pm_sem);
 339         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 340                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 341                         mode = i;
 342                         break;
 343                 }
 344         }
 345         if (mode) {
 346                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 347                         pm_disk_mode = mode;
 348                 else {
 349                         if (pm_ops && pm_ops->enter &&
 350                             (mode == pm_ops->pm_disk_mode))
 351                                 pm_disk_mode = mode;
 352                         else
 353                                 error = -EINVAL;
 354                 }
 355         } else
 356                 error = -EINVAL;
 357
 358         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 359                  pm_disk_modes[mode]);
 360         up(&pm_sem);
 361         return error ? error : n;
 362 }
 363
 364 power_attr(disk);
 365
 366 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 367 {
 368         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 369                        MINOR(swsusp_resume_device));
 370 }
 371
 372 static ssize_t resume_store(struct subsystem * subsys, const char * buf, size_t n)
 373 {
 374         int len;
 375         char *p;
 376         unsigned int maj, min;
 377         int error = -EINVAL;
 378         dev_t res;
 379
 380         p = memchr(buf, '\n', n);
 381         len = p ? p - buf : n;
 382
 383         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
 384                 res = MKDEV(maj,min);
 385                 if (maj == MAJOR(res) && min == MINOR(res)) {
 386                         down(&pm_sem);
 387                         swsusp_resume_device = res;
 388                         up(&pm_sem);
 389                         printk("Attempting manual resume\n");
 390                         noresume = 0;
 391                         software_resume();
 392                 }
 393         }
 394
 395         return error >= 0 ? n : error;
 396 }
 397
 398 power_attr(resume);
 399
 400 static struct attribute * g[] = {
 401         &disk_attr.attr,
 402         &resume_attr.attr,
 403         NULL,
 404 };
 405
 406
 407 static struct attribute_group attr_group = {
 408         .attrs = g,
 409 };
 410
 411
 412 static int __init pm_disk_init(void)
 413 {
 414         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 415 }
 416
 417 core_initcall(pm_disk_init);
 418
 419
 420 static int __init resume_setup(char *str)
 421 {
 422         if (noresume)
 423                 return 1;
 424
 425         strncpy( resume_file, str, 255 );
 426         return 1;
 427 }
 428
 429 static int __init noresume_setup(char *str)
 430 {
 431         noresume = 1;
 432         return 1;
 433 }
 434
 435 __setup("noresume", noresume_setup);
 436 __setup("resume=", resume_setup);