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