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                 if (pm_ops && pm_ops->enter) {
  48                         kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
  49                         error = pm_ops->enter(PM_SUSPEND_DISK);
  50                         break;
  51                 }
  52         case PM_DISK_SHUTDOWN:
  53                 kernel_power_off();
  54                 break;
  55         case PM_DISK_REBOOT:
  56                 kernel_restart(NULL);
  57                 break;
  58         }
  59         kernel_halt();
  60         /* Valid image is on the disk, if we continue we risk serious data corruption
  61            after resume. */
  62         printk(KERN_CRIT "Please power me down manually\n");
  63         while(1);
  64 }
  65
  66 static inline void platform_finish(void)
  67 {
  68         if (pm_disk_mode == PM_DISK_PLATFORM) {
  69                 if (pm_ops && pm_ops->finish)
  70                         pm_ops->finish(PM_SUSPEND_DISK);
  71         }
  72 }
  73
  74 static int prepare_processes(void)
  75 {
  76         int error;
  77
  78         pm_prepare_console();
  79
  80         error = disable_nonboot_cpus();
  81         if (error)
  82                 goto enable_cpus;
  83
  84         if (freeze_processes()) {
  85                 error = -EBUSY;
  86                 goto thaw;
  87         }
  88
  89         /* Free memory before shutting down devices. */
  90         if (!(error = swsusp_shrink_memory()))
  91                 return 0;
  92 thaw:
  93         thaw_processes();
  94 enable_cpus:
  95         enable_nonboot_cpus();
  96         pm_restore_console();
  97         return error;
  98 }
  99
 100 static void unprepare_processes(void)
 101 {
 102         platform_finish();
 103         thaw_processes();
 104         enable_nonboot_cpus();
 105         pm_restore_console();
 106 }
 107
 108 /**
 109  *      pm_suspend_disk - The granpappy of hibernation power management.
 110  *
 111  *      If we're going through the firmware, then get it over with quickly.
 112  *
 113  *      If not, then call swsusp to do its thing, then figure out how
 114  *      to power down the system.
 115  */
 116
 117 int pm_suspend_disk(void)
 118 {
 119         int error;
 120
 121         error = prepare_processes();
 122         if (error)
 123                 return error;
 124
 125         suspend_console();
 126         error = device_suspend(PMSG_FREEZE);
 127         if (error) {
 128                 resume_console();
 129                 printk("Some devices failed to suspend\n");
 130                 unprepare_processes();
 131                 return error;
 132         }
 133
 134         pr_debug("PM: snapshotting memory.\n");
 135         in_suspend = 1;
 136         if ((error = swsusp_suspend()))
 137                 goto Done;
 138
 139         if (in_suspend) {
 140                 device_resume();
 141                 resume_console();
 142                 pr_debug("PM: writing image.\n");
 143                 error = swsusp_write();
 144                 if (!error)
 145                         power_down(pm_disk_mode);
 146                 else {
 147                         swsusp_free();
 148                         unprepare_processes();
 149                         return error;
 150                 }
 151         } else
 152                 pr_debug("PM: Image restored successfully.\n");
 153
 154         swsusp_free();
 155  Done:
 156         device_resume();
 157         resume_console();
 158         unprepare_processes();
 159         return error;
 160 }
 161
 162
 163 /**
 164  *      software_resume - Resume from a saved image.
 165  *
 166  *      Called as a late_initcall (so all devices are discovered and
 167  *      initialized), we call swsusp to see if we have a saved image or not.
 168  *      If so, we quiesce devices, the restore the saved image. We will
 169  *      return above (in pm_suspend_disk() ) if everything goes well.
 170  *      Otherwise, we fail gracefully and return to the normally
 171  *      scheduled program.
 172  *
 173  */
 174
 175 static int software_resume(void)
 176 {
 177         int error;
 178
 179         down(&pm_sem);
 180         if (!swsusp_resume_device) {
 181                 if (!strlen(resume_file)) {
 182                         up(&pm_sem);
 183                         return -ENOENT;
 184                 }
 185                 swsusp_resume_device = name_to_dev_t(resume_file);
 186                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 187         } else {
 188                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 189                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 190         }
 191
 192         if (noresume) {
 193                 /**
 194                  * FIXME: If noresume is specified, we need to find the partition
 195                  * and reset it back to normal swap space.
 196                  */
 197                 up(&pm_sem);
 198                 return 0;
 199         }
 200
 201         pr_debug("PM: Checking swsusp image.\n");
 202
 203         if ((error = swsusp_check()))
 204                 goto Done;
 205
 206         pr_debug("PM: Preparing processes for restore.\n");
 207
 208         if ((error = prepare_processes())) {
 209                 swsusp_close();
 210                 goto Done;
 211         }
 212
 213         pr_debug("PM: Reading swsusp image.\n");
 214
 215         if ((error = swsusp_read())) {
 216                 swsusp_free();
 217                 goto Thaw;
 218         }
 219
 220         pr_debug("PM: Preparing devices for restore.\n");
 221
 222         suspend_console();
 223         if ((error = device_suspend(PMSG_PRETHAW))) {
 224                 resume_console();
 225                 printk("Some devices failed to suspend\n");
 226                 swsusp_free();
 227                 goto Thaw;
 228         }
 229
 230         mb();
 231
 232         pr_debug("PM: Restoring saved image.\n");
 233         swsusp_resume();
 234         pr_debug("PM: Restore failed, recovering.n");
 235         device_resume();
 236         resume_console();
 237  Thaw:
 238         unprepare_processes();
 239  Done:
 240         /* For success case, the suspend path will release the lock */
 241         up(&pm_sem);
 242         pr_debug("PM: Resume from disk failed.\n");
 243         return 0;
 244 }
 245
 246 late_initcall(software_resume);
 247
 248
 249 static const char * const 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         suspend_disk_method_t 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 ssize_t resume_show(struct subsystem * subsys, char *buf)
 329 {
 330         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 331                        MINOR(swsusp_resume_device));
 332 }
 333
 334 static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
 335 {
 336         unsigned int maj, min;
 337         dev_t res;
 338         int ret = -EINVAL;
 339
 340         if (sscanf(buf, "%u:%u", &maj, &min) != 2)
 341                 goto out;
 342
 343         res = MKDEV(maj,min);
 344         if (maj != MAJOR(res) || min != MINOR(res))
 345                 goto out;
 346
 347         down(&pm_sem);
 348         swsusp_resume_device = res;
 349         up(&pm_sem);
 350         printk("Attempting manual resume\n");
 351         noresume = 0;
 352         software_resume();
 353         ret = n;
 354 out:
 355         return ret;
 356 }
 357
 358 power_attr(resume);
 359
 360 static ssize_t image_size_show(struct subsystem * subsys, char *buf)
 361 {
 362         return sprintf(buf, "%lu\n", image_size);
 363 }
 364
 365 static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
 366 {
 367         unsigned long size;
 368
 369         if (sscanf(buf, "%lu", &size) == 1) {
 370                 image_size = size;
 371                 return n;
 372         }
 373
 374         return -EINVAL;
 375 }
 376
 377 power_attr(image_size);
 378
 379 static struct attribute * g[] = {
 380         &disk_attr.attr,
 381         &resume_attr.attr,
 382         &image_size_attr.attr,
 383         NULL,
 384 };
 385
 386
 387 static struct attribute_group attr_group = {
 388         .attrs = g,
 389 };
 390
 391
 392 static int __init pm_disk_init(void)
 393 {
 394         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 395 }
 396
 397 core_initcall(pm_disk_init);
 398
 399
 400 static int __init resume_setup(char *str)
 401 {
 402         if (noresume)
 403                 return 1;
 404
 405         strncpy( resume_file, str, 255 );
 406         return 1;
 407 }
 408
 409 static int __init noresume_setup(char *str)
 410 {
 411         noresume = 1;
 412         return 1;
 413 }
 414
 415 __setup("noresume", noresume_setup);
 416 __setup("resume=", resume_setup);