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 "power.h"
  20
  21
  22 extern suspend_disk_method_t pm_disk_mode;
  23 extern struct pm_ops * pm_ops;
  24
  25 extern int swsusp_suspend(void);
  26 extern int swsusp_write(void);
  27 extern int swsusp_check(void);
  28 extern int swsusp_read(void);
  29 extern void swsusp_close(void);
  30 extern int swsusp_resume(void);
  31 extern int swsusp_free(void);
  32
  33
  34 static int noresume = 0;
  35 char resume_file[256] = CONFIG_PM_STD_PARTITION;
  36 dev_t swsusp_resume_device;
  37
  38 /**
  39  *      power_down - Shut machine down for hibernate.
  40  *      @mode:          Suspend-to-disk mode
  41  *
  42  *      Use the platform driver, if configured so, and return gracefully if it
  43  *      fails.
  44  *      Otherwise, try to power off and reboot. If they fail, halt the machine,
  45  *      there ain't no turning back.
  46  */
  47
  48 static void power_down(suspend_disk_method_t mode)
  49 {
  50         unsigned long flags;
  51         int error = 0;
  52
  53         local_irq_save(flags);
  54         switch(mode) {
  55         case PM_DISK_PLATFORM:
  56                 device_shutdown();
  57                 error = pm_ops->enter(PM_SUSPEND_DISK);
  58                 break;
  59         case PM_DISK_SHUTDOWN:
  60                 printk("Powering off system\n");
  61                 device_shutdown();
  62                 machine_power_off();
  63                 break;
  64         case PM_DISK_REBOOT:
  65                 device_shutdown();
  66                 machine_restart(NULL);
  67                 break;
  68         }
  69         machine_halt();
  70         /* Valid image is on the disk, if we continue we risk serious data corruption
  71            after resume. */
  72         printk(KERN_CRIT "Please power me down manually\n");
  73         while(1);
  74 }
  75
  76
  77 static int in_suspend __nosavedata = 0;
  78
  79
  80 /**
  81  *      free_some_memory -  Try to free as much memory as possible
  82  *
  83  *      ... but do not OOM-kill anyone
  84  *
  85  *      Notice: all userland should be stopped at this point, or
  86  *      livelock is possible.
  87  */
  88
  89 static void free_some_memory(void)
  90 {
  91         unsigned int i = 0;
  92         unsigned int tmp;
  93         unsigned long pages = 0;
  94         char *p = "-\\|/";
  95
  96         printk("Freeing memory...  ");
  97         while ((tmp = shrink_all_memory(10000))) {
  98                 pages += tmp;
  99                 printk("\b%c", p[i]);
 100                 i++;
 101                 if (i > 3)
 102                         i = 0;
 103         }
 104         printk("\bdone (%li pages freed)\n", pages);
 105 }
 106
 107
 108 static inline void platform_finish(void)
 109 {
 110         if (pm_disk_mode == PM_DISK_PLATFORM) {
 111                 if (pm_ops && pm_ops->finish)
 112                         pm_ops->finish(PM_SUSPEND_DISK);
 113         }
 114 }
 115
 116 static void finish(void)
 117 {
 118         device_resume();
 119         platform_finish();
 120         thaw_processes();
 121         enable_nonboot_cpus();
 122         pm_restore_console();
 123 }
 124
 125
 126 static int prepare_processes(void)
 127 {
 128         int error;
 129
 130         pm_prepare_console();
 131
 132         sys_sync();
 133
 134         disable_nonboot_cpus();
 135
 136         if (freeze_processes()) {
 137                 error = -EBUSY;
 138                 goto thaw;
 139         }
 140
 141         if (pm_disk_mode == PM_DISK_PLATFORM) {
 142                 if (pm_ops && pm_ops->prepare) {
 143                         if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
 144                                 goto thaw;
 145                 }
 146         }
 147
 148         /* Free memory before shutting down devices. */
 149         free_some_memory();
 150         return 0;
 151 thaw:
 152         thaw_processes();
 153         enable_nonboot_cpus();
 154         pm_restore_console();
 155         return error;
 156 }
 157
 158 static void unprepare_processes(void)
 159 {
 160         platform_finish();
 161         thaw_processes();
 162         enable_nonboot_cpus();
 163         pm_restore_console();
 164 }
 165
 166 static int prepare_devices(void)
 167 {
 168         int error;
 169
 170         if ((error = device_suspend(PMSG_FREEZE)))
 171                 printk("Some devices failed to suspend\n");
 172         return error;
 173 }
 174
 175 /**
 176  *      pm_suspend_disk - The granpappy of power management.
 177  *
 178  *      If we're going through the firmware, then get it over with quickly.
 179  *
 180  *      If not, then call swsusp to do its thing, then figure out how
 181  *      to power down the system.
 182  */
 183
 184 int pm_suspend_disk(void)
 185 {
 186         int error;
 187
 188         error = prepare_processes();
 189         if (error)
 190                 return error;
 191         error = prepare_devices();
 192
 193         if (error) {
 194                 unprepare_processes();
 195                 return error;
 196         }
 197
 198         pr_debug("PM: Attempting to suspend to disk.\n");
 199         if (pm_disk_mode == PM_DISK_FIRMWARE)
 200                 return pm_ops->enter(PM_SUSPEND_DISK);
 201
 202         pr_debug("PM: snapshotting memory.\n");
 203         in_suspend = 1;
 204         if ((error = swsusp_suspend()))
 205                 goto Done;
 206
 207         if (in_suspend) {
 208                 pr_debug("PM: writing image.\n");
 209                 error = swsusp_write();
 210                 if (!error)
 211                         power_down(pm_disk_mode);
 212         } else
 213                 pr_debug("PM: Image restored successfully.\n");
 214         swsusp_free();
 215  Done:
 216         finish();
 217         return error;
 218 }
 219
 220
 221 /**
 222  *      software_resume - Resume from a saved image.
 223  *
 224  *      Called as a late_initcall (so all devices are discovered and
 225  *      initialized), we call swsusp to see if we have a saved image or not.
 226  *      If so, we quiesce devices, the restore the saved image. We will
 227  *      return above (in pm_suspend_disk() ) if everything goes well.
 228  *      Otherwise, we fail gracefully and return to the normally
 229  *      scheduled program.
 230  *
 231  */
 232
 233 static int software_resume(void)
 234 {
 235         int error;
 236
 237         if (noresume) {
 238                 /**
 239                  * FIXME: If noresume is specified, we need to find the partition
 240                  * and reset it back to normal swap space.
 241                  */
 242                 return 0;
 243         }
 244
 245         pr_debug("PM: Checking swsusp image.\n");
 246
 247         if ((error = swsusp_check()))
 248                 goto Done;
 249
 250         pr_debug("PM: Preparing processes for restore.\n");
 251
 252         if ((error = prepare_processes())) {
 253                 swsusp_close();
 254                 goto Done;
 255         }
 256
 257         pr_debug("PM: Reading swsusp image.\n");
 258
 259         if ((error = swsusp_read()))
 260                 goto Cleanup;
 261
 262         pr_debug("PM: Preparing devices for restore.\n");
 263
 264         if ((error = prepare_devices()))
 265                 goto Free;
 266
 267         mb();
 268
 269         pr_debug("PM: Restoring saved image.\n");
 270         swsusp_resume();
 271         pr_debug("PM: Restore failed, recovering.n");
 272         finish();
 273  Free:
 274         swsusp_free();
 275  Cleanup:
 276         unprepare_processes();
 277  Done:
 278         pr_debug("PM: Resume from disk failed.\n");
 279         return 0;
 280 }
 281
 282 late_initcall(software_resume);
 283
 284
 285 static char * pm_disk_modes[] = {
 286         [PM_DISK_FIRMWARE]      = "firmware",
 287         [PM_DISK_PLATFORM]      = "platform",
 288         [PM_DISK_SHUTDOWN]      = "shutdown",
 289         [PM_DISK_REBOOT]        = "reboot",
 290 };
 291
 292 /**
 293  *      disk - Control suspend-to-disk mode
 294  *
 295  *      Suspend-to-disk can be handled in several ways. The greatest
 296  *      distinction is who writes memory to disk - the firmware or the OS.
 297  *      If the firmware does it, we assume that it also handles suspending
 298  *      the system.
 299  *      If the OS does it, then we have three options for putting the system
 300  *      to sleep - using the platform driver (e.g. ACPI or other PM registers),
 301  *      powering off the system or rebooting the system (for testing).
 302  *
 303  *      The system will support either 'firmware' or 'platform', and that is
 304  *      known a priori (and encoded in pm_ops). But, the user may choose
 305  *      'shutdown' or 'reboot' as alternatives.
 306  *
 307  *      show() will display what the mode is currently set to.
 308  *      store() will accept one of
 309  *
 310  *      'firmware'
 311  *      'platform'
 312  *      'shutdown'
 313  *      'reboot'
 314  *
 315  *      It will only change to 'firmware' or 'platform' if the system
 316  *      supports it (as determined from pm_ops->pm_disk_mode).
 317  */
 318
 319 static ssize_t disk_show(struct subsystem * subsys, char * buf)
 320 {
 321         return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
 322 }
 323
 324
 325 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 326 {
 327         int error = 0;
 328         int i;
 329         int len;
 330         char *p;
 331         suspend_disk_method_t mode = 0;
 332
 333         p = memchr(buf, '\n', n);
 334         len = p ? p - buf : n;
 335
 336         down(&pm_sem);
 337         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
 338                 if (!strncmp(buf, pm_disk_modes[i], len)) {
 339                         mode = i;
 340                         break;
 341                 }
 342         }
 343         if (mode) {
 344                 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
 345                         pm_disk_mode = mode;
 346                 else {
 347                         if (pm_ops && pm_ops->enter &&
 348                             (mode == pm_ops->pm_disk_mode))
 349                                 pm_disk_mode = mode;
 350                         else
 351                                 error = -EINVAL;
 352                 }
 353         } else
 354                 error = -EINVAL;
 355
 356         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
 357                  pm_disk_modes[mode]);
 358         up(&pm_sem);
 359         return error ? error : n;
 360 }
 361
 362 power_attr(disk);
 363
 364 static ssize_t resume_show(struct subsystem * subsys, char *buf)
 365 {
 366         return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
 367                        MINOR(swsusp_resume_device));
 368 }
 369
 370 static ssize_t resume_store(struct subsystem * subsys, const char * buf, size_t n)
 371 {
 372         int len;
 373         char *p;
 374         unsigned int maj, min;
 375         int error = -EINVAL;
 376         dev_t res;
 377
 378         p = memchr(buf, '\n', n);
 379         len = p ? p - buf : n;
 380
 381         if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
 382                 res = MKDEV(maj,min);
 383                 if (maj == MAJOR(res) && min == MINOR(res)) {
 384                         swsusp_resume_device = res;
 385                         printk("Attempting manual resume\n");
 386                         noresume = 0;
 387                         software_resume();
 388                 }
 389         }
 390
 391         return error >= 0 ? n : error;
 392 }
 393
 394 power_attr(resume);
 395
 396 static struct attribute * g[] = {
 397         &disk_attr.attr,
 398         &resume_attr.attr,
 399         NULL,
 400 };
 401
 402
 403 static struct attribute_group attr_group = {
 404         .attrs = g,
 405 };
 406
 407
 408 static int __init pm_disk_init(void)
 409 {
 410         return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
 411 }
 412
 413 core_initcall(pm_disk_init);
 414
 415
 416 static int __init resume_setup(char *str)
 417 {
 418         if (noresume)
 419                 return 1;
 420
 421         strncpy( resume_file, str, 255 );
 422         return 1;
 423 }
 424
 425 static int __init noresume_setup(char *str)
 426 {
 427         noresume = 1;
 428         return 1;
 429 }
 430
 431 __setup("noresume", noresume_setup);
 432 __setup("resume=", resume_setup);