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                 printk("Powering off system\n");
  63                 device_shutdown();
  64                 machine_power_off();
  65                 break;
  66         case PM_DISK_REBOOT:
  67                 device_shutdown();
  68                 machine_restart(NULL);
  69                 break;
  70         }
  71         machine_halt();
  72         /* Valid image is on the disk, if we continue we risk serious data corruption
  73            after resume. */
  74         printk(KERN_CRIT "Please power me down manually\n");
  75         while(1);
  76 }
  77
  78
  79 static int in_suspend __nosavedata = 0;
  80
  81
  82 /**
  83  *      free_some_memory -  Try to free as much memory as possible
  84  *
  85  *      ... but do not OOM-kill anyone
  86  *
  87  *      Notice: all userland should be stopped at this point, or
  88  *      livelock is possible.
  89  */
  90
  91 static void free_some_memory(void)
  92 {
  93         unsigned int i = 0;
  94         unsigned int tmp;
  95         unsigned long pages = 0;
  96         char *p = "-\\|/";
  97
  98         printk("Freeing memory...  ");
  99         while ((tmp = shrink_all_memory(10000))) {
 100                 pages += tmp;
 101                 printk("\b%c", p[i]);
 102                 i++;
 103                 if (i > 3)
 104                         i = 0;
 105         }
 106         printk("\bdone (%li pages freed)\n", pages);
 107 }
 108
 109
 110 static inline void platform_finish(void)
 111 {
 112         if (pm_disk_mode == PM_DISK_PLATFORM) {
 113                 if (pm_ops && pm_ops->finish)
 114                         pm_ops->finish(PM_SUSPEND_DISK);
 115         }
 116 }
 117
 118 static void finish(void)
 119 {
 120         device_resume();
 121         platform_finish();
 122         thaw_processes();
 123         enable_nonboot_cpus();
 124         pm_restore_console();
 125 }
 126
 127
 128 static int prepare_processes(void)
 129 {
 130         int error;
 131
 132         pm_prepare_console();
 133
 134         sys_sync();
 135
 136         disable_nonboot_cpus();
 137
 138         if (freeze_processes()) {
 139                 error = -EBUSY;
 140                 goto thaw;
 141         }
 142
 143         if (pm_disk_mode == PM_DISK_PLATFORM) {
 144                 if (pm_ops && pm_ops->prepare) {
 145                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 146                                 goto thaw;
 147                 }
 148         }
 149
 150         /* Free memory before shutting down devices. */
 151         free_some_memory();
 152         return 0;
 153 thaw:
 154         thaw_processes();
 155         enable_nonboot_cpus();
 156         pm_restore_console();
 157         return error;
 158 }
 159
 160 static void unprepare_processes(void)
 161 {
 162         platform_finish();
 163         thaw_processes();
 164         enable_nonboot_cpus();
 165         pm_restore_console();
 166 }
 167
 168 static int prepare_devices(void)
 169 {
 170         int error;
 171
 172         if ((error = device_suspend(PMSG_FREEZE)))
 173                 printk("Some devices failed to suspend\n");
 174         return error;
 175 }
 176
 177 /**
 178  *      pm_suspend_disk - The granpappy of power management.
 179  *
 180  *      If we're going through the firmware, then get it over with quickly.
 181  *
 182  *      If not, then call swsusp to do its thing, then figure out how
 183  *      to power down the system.
 184  */
 185
 186 int pm_suspend_disk(void)
 187 {
 188         int error;
 189
 190         error = prepare_processes();
 191         if (error)
 192                 return error;
 193         error = prepare_devices();
 194
 195         if (error) {
 196                 unprepare_processes();
 197                 return error;
 198         }
 199
 200         pr_debug("PM: Attempting to suspend to disk.\n");
 201         if (pm_disk_mode == PM_DISK_FIRMWARE)
 202                 return pm_ops->enter(PM_SUSPEND_DISK);
 203
 204         pr_debug("PM: snapshotting memory.\n");
 205         in_suspend = 1;
 206         if ((error = swsusp_suspend()))
 207                 goto Done;
 208
 209         if (in_suspend) {
 210                 pr_debug("PM: writing image.\n");
 211                 error = swsusp_write();
 212                 if (!error)
 213                         power_down(pm_disk_mode);
 214         } else
 215                 pr_debug("PM: Image restored successfully.\n");
 216         swsusp_free();
 217  Done:
 218         finish();
 219         return error;
 220 }
 221
 222
 223 /**
 224  *      software_resume - Resume from a saved image.
 225  *
 226  *      Called as a late_initcall (so all devices are discovered and
 227  *      initialized), we call swsusp to see if we have a saved image or not.
 228  *      If so, we quiesce devices, the restore the saved image. We will
 229  *      return above (in pm_suspend_disk() ) if everything goes well.
 230  *      Otherwise, we fail gracefully and return to the normally
 231  *      scheduled program.
 232  *
 233  */
 234
 235 static int software_resume(void)
 236 {
 237         int error;
 238
 239         if (!swsusp_resume_device) {
 240                 if (!strlen(resume_file))
 241                         return -ENOENT;
 242                 swsusp_resume_device = name_to_dev_t(resume_file);
 243                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 244         } else {
 245                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 246                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 247         }
 248
 249         if (noresume) {
 250                 /**
 251                  * FIXME: If noresume is specified, we need to find the partition
 252                  * and reset it back to normal swap space.
 253                  */
 254                 return 0;
 255         }
 256
 257         pr_debug("PM: Checking swsusp image.\n");
 258
 259         if ((error = swsusp_check()))
 260                 goto Done;
 261
 262         pr_debug("PM: Preparing processes for restore.\n");
 263
 264         if ((error = prepare_processes())) {
 265                 swsusp_close();
 266                 goto Done;
 267         }
 268
 269         pr_debug("PM: Reading swsusp image.\n");
 270
 271         if ((error = swsusp_read()))
 272                 goto Cleanup;
 273
 274         pr_debug("PM: Preparing devices for restore.\n");
 275
 276         if ((error = prepare_devices()))
 277                 goto Free;
 278
 279         mb();
 280
 281         pr_debug("PM: Restoring saved image.\n");
 282         swsusp_resume();
 283         pr_debug("PM: Restore failed, recovering.n");
 284         finish();
 285  Free:
 286         swsusp_free();
 287  Cleanup:
 288         unprepare_processes();
 289  Done:
 290         pr_debug("PM: Resume from disk failed.\n");
 291         return 0;
 292 }
 293
 294 late_initcall(software_resume);
 295
 296
 297 static char * pm_disk_modes[] = {
 298         [PM_DISK_FIRMWARE]      = "firmware",
 299         [PM_DISK_PLATFORM]      = "platform",
 300         [PM_DISK_SHUTDOWN]      = "shutdown",
 301         [PM_DISK_REBOOT]        = "reboot",
 302 };
 303
 304 /**
 305  *      disk - Control suspend-to-disk mode
 306  *
 307  *      Suspend-to-disk can be handled in several ways. The greatest
 308  *      distinction is who writes memory to disk - the firmware or the OS.
 309  *      If the firmware does it, we assume that it also handles suspending
 310  *      the system.
 311  *      If the OS does it, then we have three options for putting the system
 312  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 313  *      powering off the system or rebooting the system (for testing).
 314  *
 315  *      The system will support either 'firmware' or 'platform', and that is
 316  *      known a priori (and encoded in pm_ops). But, the user may choose
 317  *      'shutdown' or 'reboot' as alternatives.
 318  *
 319  *      show() will display what the mode is currently set to.
 320  *      store() will accept one of
 321  *
 322  *      'firmware'
 323  *      'platform'
 324  *      'shutdown'
 325  *      'reboot'
 326  *
 327  *      It will only change to 'firmware' or 'platform' if the system
 328  *      supports it (as determined from pm_ops->pm_disk_mode).
 329  */
 330
 331 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 332 {
 333         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 334 }
 335
 336
 337 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 338 {
 339         int error = 0;
 340         int i;
 341         int len;
 342         char *p;
 343         suspend_disk_method_t mode = 0;
 344
 345         p = memchr(buf, '\n', n);
 346         len = p ? p - buf : n;
 347
 348         down(&pm_sem);
 349         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 350                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 351                         mode = i;
 352                         break;
 353                 }
 354         }
 355         if (mode) {
 356                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 357                         pm_disk_mode = mode;
 358                 else {
 359                         if (pm_ops && pm_ops->enter &&
 360                             (mode == pm_ops->pm_disk_mode))
 361                                 pm_disk_mode = mode;
 362                         else
 363                                 error = -EINVAL;
 364                 }
 365         } else
 366                 error = -EINVAL;
 367
 368         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 369                  pm_disk_modes[mode]);
 370         up(&pm_sem);
 371         return error ? error : n;
 372 }
 373
 374 power_attr(disk);
 375
 376 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 377 {
 378         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 379                        MINOR(swsusp_resume_device));
 380 }
 381
 382 static ssize_t resume_store(struct subsystem * subsys, const char * buf, size_t n)
 383 {
 384         int len;
 385         char *p;
 386         unsigned int maj, min;
 387         int error = -EINVAL;
 388         dev_t res;
 389
 390         p = memchr(buf, '\n', n);
 391         len = p ? p - buf : n;
 392
 393         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
 394                 res = MKDEV(maj,min);
 395                 if (maj == MAJOR(res) && min == MINOR(res)) {
 396                         swsusp_resume_device = res;
 397                         printk("Attempting manual resume\n");
 398                         noresume = 0;
 399                         software_resume();
 400                 }
 401         }
 402
 403         return error >= 0 ? n : error;
 404 }
 405
 406 power_attr(resume);
 407
 408 static struct attribute * g[] = {
 409         &disk_attr.attr,
 410         &resume_attr.attr,
 411         NULL,
 412 };
 413
 414
 415 static struct attribute_group attr_group = {
 416         .attrs = g,
 417 };
 418
 419
 420 static int __init pm_disk_init(void)
 421 {
 422         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 423 }
 424
 425 core_initcall(pm_disk_init);
 426
 427
 428 static int __init resume_setup(char *str)
 429 {
 430         if (noresume)
 431                 return 1;
 432
 433         strncpy( resume_file, str, 255 );
 434         return 1;
 435 }
 436
 437 static int __init noresume_setup(char *str)
 438 {
 439         noresume = 1;
 440         return 1;
 441 }
 442
 443 __setup("noresume", noresume_setup);
 444 __setup("resume=", resume_setup);