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