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