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_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
  34
  35 static int noresume = 0;
  36 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  37 dev_t swsusp_resume_device;
  38
  39 /**
  40  *      power_down - Shut machine down for hibernate.
  41  *      @mode:          Suspend-to-disk mode
  42  *
  43  *      Use the platform driver, if configured so, and return gracefully if it
  44  *      fails.
  45  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  46  *      there ain't no turning back.
  47  */
  48
  49 static void power_down(suspend_disk_method_t mode)
  50 {
  51         int error = 0;
  52
  53         switch(mode) {
  54         case PM_DISK_PLATFORM:
  55                 kernel_power_off_prepare();
  56                 error = pm_ops->enter(PM_SUSPEND_DISK);
  57                 break;
  58         case PM_DISK_SHUTDOWN:
  59                 kernel_power_off();
  60                 break;
  61         case PM_DISK_REBOOT:
  62                 kernel_restart(NULL);
  63                 break;
  64         }
  65         kernel_halt();
  66         /* Valid image is on the disk, if we continue we risk serious data corruption
  67            after resume. */
  68         printk(KERN_CRIT "Please power me down manually\n");
  69         while(1);
  70 }
  71
  72
  73 static int in_suspend __nosavedata = 0;
  74
  75
  76 /**
  77  *      free_some_memory -  Try to free as much memory as possible
  78  *
  79  *      ... but do not OOM-kill anyone
  80  *
  81  *      Notice: all userland should be stopped at this point, or
  82  *      livelock is possible.
  83  */
  84
  85 static void free_some_memory(void)
  86 {
  87         unsigned int i = 0;
  88         unsigned int tmp;
  89         unsigned long pages = 0;
  90         char *p = "-\\|/";
  91
  92         printk("Freeing memory...  ");
  93         while ((tmp = shrink_all_memory(10000))) {
  94                 pages += tmp;
  95                 printk("\b%c", p[i++ % 4]);
  96         }
  97         printk("\bdone (%li pages freed)\n", pages);
  98 }
  99
 100
 101 static inline void platform_finish(void)
 102 {
 103         if (pm_disk_mode == PM_DISK_PLATFORM) {
 104                 if (pm_ops && pm_ops->finish)
 105                         pm_ops->finish(PM_SUSPEND_DISK);
 106         }
 107 }
 108
 109 static int prepare_processes(void)
 110 {
 111         int error;
 112
 113         pm_prepare_console();
 114         sys_sync();
 115         disable_nonboot_cpus();
 116
 117         if (freeze_processes()) {
 118                 error = -EBUSY;
 119                 goto thaw;
 120         }
 121
 122         if (pm_disk_mode == PM_DISK_PLATFORM) {
 123                 if (pm_ops && pm_ops->prepare) {
 124                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 125                                 goto thaw;
 126                 }
 127         }
 128
 129         /* Free memory before shutting down devices. */
 130         free_some_memory();
 131         return 0;
 132 thaw:
 133         thaw_processes();
 134         enable_nonboot_cpus();
 135         pm_restore_console();
 136         return error;
 137 }
 138
 139 static void unprepare_processes(void)
 140 {
 141         platform_finish();
 142         thaw_processes();
 143         enable_nonboot_cpus();
 144         pm_restore_console();
 145 }
 146
 147 /**
 148  *      pm_suspend_disk - The granpappy of power management.
 149  *
 150  *      If we're going through the firmware, then get it over with quickly.
 151  *
 152  *      If not, then call swsusp to do its thing, then figure out how
 153  *      to power down the system.
 154  */
 155
 156 int pm_suspend_disk(void)
 157 {
 158         int error;
 159
 160         error = prepare_processes();
 161         if (error)
 162                 return error;
 163
 164         error = device_suspend(PMSG_FREEZE);
 165         if (error) {
 166                 printk("Some devices failed to suspend\n");
 167                 unprepare_processes();
 168                 return error;
 169         }
 170
 171         pr_debug("PM: snapshotting memory.\n");
 172         in_suspend = 1;
 173         if ((error = swsusp_suspend()))
 174                 goto Done;
 175
 176         if (in_suspend) {
 177                 device_resume();
 178                 pr_debug("PM: writing image.\n");
 179                 error = swsusp_write();
 180                 if (!error)
 181                         power_down(pm_disk_mode);
 182                 else {
 183                         swsusp_free();
 184                         unprepare_processes();
 185                         return error;
 186                 }
 187         } else
 188                 pr_debug("PM: Image restored successfully.\n");
 189
 190         swsusp_free();
 191  Done:
 192         device_resume();
 193         unprepare_processes();
 194         return error;
 195 }
 196
 197
 198 /**
 199  *      software_resume - Resume from a saved image.
 200  *
 201  *      Called as a late_initcall (so all devices are discovered and
 202  *      initialized), we call swsusp to see if we have a saved image or not.
 203  *      If so, we quiesce devices, the restore the saved image. We will
 204  *      return above (in pm_suspend_disk() ) if everything goes well.
 205  *      Otherwise, we fail gracefully and return to the normally
 206  *      scheduled program.
 207  *
 208  */
 209
 210 static int software_resume(void)
 211 {
 212         int error;
 213
 214         down(&pm_sem);
 215         if (!swsusp_resume_device) {
 216                 if (!strlen(resume_file)) {
 217                         up(&pm_sem);
 218                         return -ENOENT;
 219                 }
 220                 swsusp_resume_device = name_to_dev_t(resume_file);
 221                 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
 222         } else {
 223                 pr_debug("swsusp: Resume From Partition %d:%d\n",
 224                          MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
 225         }
 226
 227         if (noresume) {
 228                 /**
 229                  * FIXME: If noresume is specified, we need to find the partition
 230                  * and reset it back to normal swap space.
 231                  */
 232                 up(&pm_sem);
 233                 return 0;
 234         }
 235
 236         pr_debug("PM: Checking swsusp image.\n");
 237
 238         if ((error = swsusp_check()))
 239                 goto Done;
 240
 241         pr_debug("PM: Preparing processes for restore.\n");
 242
 243         if ((error = prepare_processes())) {
 244                 swsusp_close();
 245                 goto Done;
 246         }
 247
 248         pr_debug("PM: Reading swsusp image.\n");
 249
 250         if ((error = swsusp_read())) {
 251                 swsusp_free();
 252                 goto Thaw;
 253         }
 254
 255         pr_debug("PM: Preparing devices for restore.\n");
 256
 257         if ((error = device_suspend(PMSG_FREEZE))) {
 258                 printk("Some devices failed to suspend\n");
 259                 swsusp_free();
 260                 goto Thaw;
 261         }
 262
 263         mb();
 264
 265         pr_debug("PM: Restoring saved image.\n");
 266         swsusp_resume();
 267         pr_debug("PM: Restore failed, recovering.n");
 268         device_resume();
 269  Thaw:
 270         unprepare_processes();
 271  Done:
 272         /* For success case, the suspend path will release the lock */
 273         up(&pm_sem);
 274         pr_debug("PM: Resume from disk failed.\n");
 275         return 0;
 276 }
 277
 278 late_initcall(software_resume);
 279
 280
 281 static char * pm_disk_modes[] = {
 282         [PM_DISK_FIRMWARE]      = "firmware",
 283         [PM_DISK_PLATFORM]      = "platform",
 284         [PM_DISK_SHUTDOWN]      = "shutdown",
 285         [PM_DISK_REBOOT]        = "reboot",
 286 };
 287
 288 /**
 289  *      disk - Control suspend-to-disk mode
 290  *
 291  *      Suspend-to-disk can be handled in several ways. The greatest
 292  *      distinction is who writes memory to disk - the firmware or the OS.
 293  *      If the firmware does it, we assume that it also handles suspending
 294  *      the system.
 295  *      If the OS does it, then we have three options for putting the system
 296  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 297  *      powering off the system or rebooting the system (for testing).
 298  *
 299  *      The system will support either 'firmware' or 'platform', and that is
 300  *      known a priori (and encoded in pm_ops). But, the user may choose
 301  *      'shutdown' or 'reboot' as alternatives.
 302  *
 303  *      show() will display what the mode is currently set to.
 304  *      store() will accept one of
 305  *
 306  *      'firmware'
 307  *      'platform'
 308  *      'shutdown'
 309  *      'reboot'
 310  *
 311  *      It will only change to 'firmware' or 'platform' if the system
 312  *      supports it (as determined from pm_ops->pm_disk_mode).
 313  */
 314
 315 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 316 {
 317         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 318 }
 319
 320
 321 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 322 {
 323         int error = 0;
 324         int i;
 325         int len;
 326         char *p;
 327         suspend_disk_method_t mode = 0;
 328
 329         p = memchr(buf, '\n', n);
 330         len = p ? p - buf : n;
 331
 332         down(&pm_sem);
 333         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 334                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 335                         mode = i;
 336                         break;
 337                 }
 338         }
 339         if (mode) {
 340                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 341                         pm_disk_mode = mode;
 342                 else {
 343                         if (pm_ops && pm_ops->enter &&
 344                             (mode == pm_ops->pm_disk_mode))
 345                                 pm_disk_mode = mode;
 346                         else
 347                                 error = -EINVAL;
 348                 }
 349         } else
 350                 error = -EINVAL;
 351
 352         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 353                  pm_disk_modes[mode]);
 354         up(&pm_sem);
 355         return error ? error : n;
 356 }
 357
 358 power_attr(disk);
 359
 360 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 361 {
 362         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 363                        MINOR(swsusp_resume_device));
 364 }
 365
 366 static ssize_t resume_store(struct subsystem * subsys, const char * buf, size_t n)
 367 {
 368         int len;
 369         char *p;
 370         unsigned int maj, min;
 371         int error = -EINVAL;
 372         dev_t res;
 373
 374         p = memchr(buf, '\n', n);
 375         len = p ? p - buf : n;
 376
 377         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
 378                 res = MKDEV(maj,min);
 379                 if (maj == MAJOR(res) && min == MINOR(res)) {
 380                         down(&pm_sem);
 381                         swsusp_resume_device = res;
 382                         up(&pm_sem);
 383                         printk("Attempting manual resume\n");
 384                         noresume = 0;
 385                         software_resume();
 386                 }
 387         }
 388
 389         return error >= 0 ? n : error;
 390 }
 391
 392 power_attr(resume);
 393
 394 static struct attribute * g[] = {
 395         &disk_attr.attr,
 396         &resume_attr.attr,
 397         NULL,
 398 };
 399
 400
 401 static struct attribute_group attr_group = {
 402         .attrs = g,
 403 };
 404
 405
 406 static int __init pm_disk_init(void)
 407 {
 408         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 409 }
 410
 411 core_initcall(pm_disk_init);
 412
 413
 414 static int __init resume_setup(char *str)
 415 {
 416         if (noresume)
 417                 return 1;
 418
 419         strncpy( resume_file, str, 255 );
 420         return 1;
 421 }
 422
 423 static int __init noresume_setup(char *str)
 424 {
 425         noresume = 1;
 426         return 1;
 427 }
 428
 429 __setup("noresume", noresume_setup);
 430 __setup("resume=", resume_setup);