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_shrink_memory(void);
  28 extern int swsusp_suspend(void);
  29 extern int swsusp_write(struct pbe *pblist, unsigned int nr_pages);
  30 extern int swsusp_check(void);
  31 extern int swsusp_read(struct pbe **pblist_ptr);
  32 extern void swsusp_close(void);
  33 extern int swsusp_resume(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         int error = 0;
  53
  54         switch(mode) {
  55         case PM_DISK_PLATFORM:
  56                 kernel_power_off_prepare();
  57                 error = pm_ops->enter(PM_SUSPEND_DISK);
  58                 break;
  59         case PM_DISK_SHUTDOWN:
  60                 kernel_power_off();
  61                 break;
  62         case PM_DISK_REBOOT:
  63                 kernel_restart(NULL);
  64                 break;
  65         }
  66         kernel_halt();
  67         /* Valid image is on the disk, if we continue we risk serious data corruption
  68            after resume. */
  69         printk(KERN_CRIT "Please power me down manually\n");
  70         while(1);
  71 }
  72
  73
  74 static int in_suspend __nosavedata = 0;
  75
  76
  77 static inline void platform_finish(void)
  78 {
  79         if (pm_disk_mode == PM_DISK_PLATFORM) {
  80                 if (pm_ops && pm_ops->finish)
  81                         pm_ops->finish(PM_SUSPEND_DISK);
  82         }
  83 }
  84
  85 static int prepare_processes(void)
  86 {
  87         int error;
  88
  89         pm_prepare_console();
  90         sys_sync();
  91         disable_nonboot_cpus();
  92
  93         if (freeze_processes()) {
  94                 error = -EBUSY;
  95                 goto thaw;
  96         }
  97
  98         if (pm_disk_mode == PM_DISK_PLATFORM) {
  99                 if (pm_ops && pm_ops->prepare) {
 100                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 101                                 goto thaw;
 102                 }
 103         }
 104
 105         /* Free memory before shutting down devices. */
 106         if (!(error = swsusp_shrink_memory()))
 107                 return 0;
 108 thaw:
 109         thaw_processes();
 110         enable_nonboot_cpus();
 111         pm_restore_console();
 112         return error;
 113 }
 114
 115 static void unprepare_processes(void)
 116 {
 117         platform_finish();
 118         thaw_processes();
 119         enable_nonboot_cpus();
 120         pm_restore_console();
 121 }
 122
 123 /**
 124  *      pm_suspend_disk - The granpappy of power management.
 125  *
 126  *      If we're going through the firmware, then get it over with quickly.
 127  *
 128  *      If not, then call swsusp to do its thing, then figure out how
 129  *      to power down the system.
 130  */
 131
 132 int pm_suspend_disk(void)
 133 {
 134         int error;
 135
 136         error = prepare_processes();
 137         if (error)
 138                 return error;
 139
 140         error = device_suspend(PMSG_FREEZE);
 141         if (error) {
 142                 printk("Some devices failed to suspend\n");
 143                 unprepare_processes();
 144                 return error;
 145         }
 146
 147         pr_debug("PM: snapshotting memory.\n");
 148         in_suspend = 1;
 149         if ((error = swsusp_suspend()))
 150                 goto Done;
 151
 152         if (in_suspend) {
 153                 device_resume();
 154                 pr_debug("PM: writing image.\n");
 155                 error = swsusp_write(pagedir_nosave, nr_copy_pages);
 156                 if (!error)
 157                         power_down(pm_disk_mode);
 158                 else {
 159                         swsusp_free();
 160                         unprepare_processes();
 161                         return error;
 162                 }
 163         } else
 164                 pr_debug("PM: Image restored successfully.\n");
 165
 166         swsusp_free();
 167  Done:
 168         device_resume();
 169         unprepare_processes();
 170         return error;
 171 }
 172
 173
 174 /**
 175  *      software_resume - Resume from a saved image.
 176  *
 177  *      Called as a late_initcall (so all devices are discovered and
 178  *      initialized), we call swsusp to see if we have a saved image or not.
 179  *      If so, we quiesce devices, the restore the saved image. We will
 180  *      return above (in pm_suspend_disk() ) if everything goes well.
 181  *      Otherwise, we fail gracefully and return to the normally
 182  *      scheduled program.
 183  *
 184  */
 185
 186 static int software_resume(void)
 187 {
 188         int error;
 189
 190         down(&pm_sem);
 191         if (!swsusp_resume_device) {
 192                 if (!strlen(resume_file)) {
 193                         up(&pm_sem);
 194                         return -ENOENT;
 195                 }
 196                 swsusp_resume_device = name_to_dev_t(resume_file);
 197                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 198         } else {
 199                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 200                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 201         }
 202
 203         if (noresume) {
 204                 /**
 205                  * FIXME: If noresume is specified, we need to find the partition
 206                  * and reset it back to normal swap space.
 207                  */
 208                 up(&pm_sem);
 209                 return 0;
 210         }
 211
 212         pr_debug("PM: Checking swsusp image.\n");
 213
 214         if ((error = swsusp_check()))
 215                 goto Done;
 216
 217         pr_debug("PM: Preparing processes for restore.\n");
 218
 219         if ((error = prepare_processes())) {
 220                 swsusp_close();
 221                 goto Done;
 222         }
 223
 224         pr_debug("PM: Reading swsusp image.\n");
 225
 226         if ((error = swsusp_read(&pagedir_nosave))) {
 227                 swsusp_free();
 228                 goto Thaw;
 229         }
 230
 231         pr_debug("PM: Preparing devices for restore.\n");
 232
 233         if ((error = device_suspend(PMSG_FREEZE))) {
 234                 printk("Some devices failed to suspend\n");
 235                 swsusp_free();
 236                 goto Thaw;
 237         }
 238
 239         mb();
 240
 241         pr_debug("PM: Restoring saved image.\n");
 242         swsusp_resume();
 243         pr_debug("PM: Restore failed, recovering.n");
 244         device_resume();
 245  Thaw:
 246         unprepare_processes();
 247  Done:
 248         /* For success case, the suspend path will release the lock */
 249         up(&pm_sem);
 250         pr_debug("PM: Resume from disk failed.\n");
 251         return 0;
 252 }
 253
 254 late_initcall(software_resume);
 255
 256
 257 static char * pm_disk_modes[] = {
 258         [PM_DISK_FIRMWARE]      = "firmware",
 259         [PM_DISK_PLATFORM]      = "platform",
 260         [PM_DISK_SHUTDOWN]      = "shutdown",
 261         [PM_DISK_REBOOT]        = "reboot",
 262 };
 263
 264 /**
 265  *      disk - Control suspend-to-disk mode
 266  *
 267  *      Suspend-to-disk can be handled in several ways. The greatest
 268  *      distinction is who writes memory to disk - the firmware or the OS.
 269  *      If the firmware does it, we assume that it also handles suspending
 270  *      the system.
 271  *      If the OS does it, then we have three options for putting the system
 272  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 273  *      powering off the system or rebooting the system (for testing).
 274  *
 275  *      The system will support either 'firmware' or 'platform', and that is
 276  *      known a priori (and encoded in pm_ops). But, the user may choose
 277  *      'shutdown' or 'reboot' as alternatives.
 278  *
 279  *      show() will display what the mode is currently set to.
 280  *      store() will accept one of
 281  *
 282  *      'firmware'
 283  *      'platform'
 284  *      'shutdown'
 285  *      'reboot'
 286  *
 287  *      It will only change to 'firmware' or 'platform' if the system
 288  *      supports it (as determined from pm_ops->pm_disk_mode).
 289  */
 290
 291 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 292 {
 293         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 294 }
 295
 296
 297 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 298 {
 299         int error = 0;
 300         int i;
 301         int len;
 302         char *p;
 303         suspend_disk_method_t mode = 0;
 304
 305         p = memchr(buf, '\n', n);
 306         len = p ? p - buf : n;
 307
 308         down(&pm_sem);
 309         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 310                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 311                         mode = i;
 312                         break;
 313                 }
 314         }
 315         if (mode) {
 316                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 317                         pm_disk_mode = mode;
 318                 else {
 319                         if (pm_ops && pm_ops->enter &&
 320                             (mode == pm_ops->pm_disk_mode))
 321                                 pm_disk_mode = mode;
 322                         else
 323                                 error = -EINVAL;
 324                 }
 325         } else
 326                 error = -EINVAL;
 327
 328         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 329                  pm_disk_modes[mode]);
 330         up(&pm_sem);
 331         return error ? error : n;
 332 }
 333
 334 power_attr(disk);
 335
 336 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 337 {
 338         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 339                        MINOR(swsusp_resume_device));
 340 }
 341
 342 static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
 343 {
 344         unsigned int maj, min;
 345         dev_t res;
 346         int ret = -EINVAL;
 347
 348         if (sscanf(buf, "%u:%u", &maj, &min) != 2)
 349                 goto out;
 350
 351         res = MKDEV(maj,min);
 352         if (maj != MAJOR(res) || min != MINOR(res))
 353                 goto out;
 354
 355         down(&pm_sem);
 356         swsusp_resume_device = res;
 357         up(&pm_sem);
 358         printk("Attempting manual resume\n");
 359         noresume = 0;
 360         software_resume();
 361         ret = n;
 362 out:
 363         return ret;
 364 }
 365
 366 power_attr(resume);
 367
 368 static ssize_t image_size_show(struct subsystem * subsys, char *buf)
 369 {
 370         return sprintf(buf, "%u\n", image_size);
 371 }
 372
 373 static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
 374 {
 375         unsigned int size;
 376
 377         if (sscanf(buf, "%u", &size) == 1) {
 378                 image_size = size;
 379                 return n;
 380         }
 381
 382         return -EINVAL;
 383 }
 384
 385 power_attr(image_size);
 386
 387 static struct attribute * g[] = {
 388         &disk_attr.attr,
 389         &resume_attr.attr,
 390         &image_size_attr.attr,
 391         NULL,
 392 };
 393
 394
 395 static struct attribute_group attr_group = {
 396         .attrs = g,
 397 };
 398
 399
 400 static int __init pm_disk_init(void)
 401 {
 402         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 403 }
 404
 405 core_initcall(pm_disk_init);
 406
 407
 408 static int __init resume_setup(char *str)
 409 {
 410         if (noresume)
 411                 return 1;
 412
 413         strncpy( resume_file, str, 255 );
 414         return 1;
 415 }
 416
 417 static int __init noresume_setup(char *str)
 418 {
 419         noresume = 1;
 420         return 1;
 421 }
 422
 423 __setup("noresume", noresume_setup);
 424 __setup("resume=", resume_setup);