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