ia64/linux-2.6.18-xen.hg

view kernel/power/disk.c @ 562:66faefe721eb

pvSCSI backend driver

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Jun 02 09:58:27 2008 +0100 (2008-06-02)
parents 831230e53067
children
line source
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 */
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>
22 #include "power.h"
25 static int noresume = 0;
26 char resume_file[256] = CONFIG_PM_STD_PARTITION;
27 dev_t swsusp_resume_device;
29 /**
30 * power_down - Shut machine down for hibernate.
31 * @mode: Suspend-to-disk mode
32 *
33 * Use the platform driver, if configured so, and return gracefully if it
34 * fails.
35 * Otherwise, try to power off and reboot. If they fail, halt the machine,
36 * there ain't no turning back.
37 */
39 static void power_down(suspend_disk_method_t mode)
40 {
41 int error = 0;
43 switch(mode) {
44 case PM_DISK_PLATFORM:
45 kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
46 error = pm_ops->enter(PM_SUSPEND_DISK);
47 break;
48 case PM_DISK_SHUTDOWN:
49 kernel_power_off();
50 break;
51 case PM_DISK_REBOOT:
52 kernel_restart(NULL);
53 break;
54 }
55 kernel_halt();
56 /* Valid image is on the disk, if we continue we risk serious data corruption
57 after resume. */
58 printk(KERN_CRIT "Please power me down manually\n");
59 while(1);
60 }
62 static inline void platform_finish(void)
63 {
64 if (pm_disk_mode == PM_DISK_PLATFORM) {
65 if (pm_ops && pm_ops->finish)
66 pm_ops->finish(PM_SUSPEND_DISK);
67 }
68 }
70 static int prepare_processes(void)
71 {
72 int error;
74 pm_prepare_console();
75 disable_nonboot_cpus();
77 if (freeze_processes()) {
78 error = -EBUSY;
79 goto thaw;
80 }
82 /* Free memory before shutting down devices. */
83 if (!(error = swsusp_shrink_memory()))
84 return 0;
85 thaw:
86 thaw_processes();
87 enable_nonboot_cpus();
88 pm_restore_console();
89 return error;
90 }
92 static void unprepare_processes(void)
93 {
94 platform_finish();
95 thaw_processes();
96 enable_nonboot_cpus();
97 pm_restore_console();
98 }
100 /**
101 * pm_suspend_disk - The granpappy of power management.
102 *
103 * If we're going through the firmware, then get it over with quickly.
104 *
105 * If not, then call swsusp to do its thing, then figure out how
106 * to power down the system.
107 */
109 int pm_suspend_disk(void)
110 {
111 int error;
113 error = prepare_processes();
114 if (error)
115 return error;
117 error = device_suspend(PMSG_FREEZE);
118 if (error) {
119 printk("Some devices failed to suspend\n");
120 unprepare_processes();
121 return error;
122 }
124 pr_debug("PM: snapshotting memory.\n");
125 in_suspend = 1;
126 if ((error = swsusp_suspend()))
127 goto Done;
129 if (in_suspend) {
130 device_resume();
131 pr_debug("PM: writing image.\n");
132 error = swsusp_write();
133 if (!error)
134 power_down(pm_disk_mode);
135 else {
136 swsusp_free();
137 unprepare_processes();
138 return error;
139 }
140 } else
141 pr_debug("PM: Image restored successfully.\n");
143 swsusp_free();
144 Done:
145 device_resume();
146 unprepare_processes();
147 return error;
148 }
151 /**
152 * software_resume - Resume from a saved image.
153 *
154 * Called as a late_initcall (so all devices are discovered and
155 * initialized), we call swsusp to see if we have a saved image or not.
156 * If so, we quiesce devices, the restore the saved image. We will
157 * return above (in pm_suspend_disk() ) if everything goes well.
158 * Otherwise, we fail gracefully and return to the normally
159 * scheduled program.
160 *
161 */
163 static int software_resume(void)
164 {
165 int error;
167 down(&pm_sem);
168 if (!swsusp_resume_device) {
169 if (!strlen(resume_file)) {
170 up(&pm_sem);
171 return -ENOENT;
172 }
173 swsusp_resume_device = name_to_dev_t(resume_file);
174 pr_debug("swsusp: Resume From Partition %s\n", resume_file);
175 } else {
176 pr_debug("swsusp: Resume From Partition %d:%d\n",
177 MAJOR(swsusp_resume_device), MINOR(swsusp_resume_device));
178 }
180 if (noresume) {
181 /**
182 * FIXME: If noresume is specified, we need to find the partition
183 * and reset it back to normal swap space.
184 */
185 up(&pm_sem);
186 return 0;
187 }
189 pr_debug("PM: Checking swsusp image.\n");
191 if ((error = swsusp_check()))
192 goto Done;
194 pr_debug("PM: Preparing processes for restore.\n");
196 if ((error = prepare_processes())) {
197 swsusp_close();
198 goto Done;
199 }
201 pr_debug("PM: Reading swsusp image.\n");
203 if ((error = swsusp_read())) {
204 swsusp_free();
205 goto Thaw;
206 }
208 pr_debug("PM: Preparing devices for restore.\n");
210 if ((error = device_suspend(PMSG_FREEZE))) {
211 printk("Some devices failed to suspend\n");
212 swsusp_free();
213 goto Thaw;
214 }
216 mb();
218 pr_debug("PM: Restoring saved image.\n");
219 swsusp_resume();
220 pr_debug("PM: Restore failed, recovering.n");
221 device_resume();
222 Thaw:
223 unprepare_processes();
224 Done:
225 /* For success case, the suspend path will release the lock */
226 up(&pm_sem);
227 pr_debug("PM: Resume from disk failed.\n");
228 return 0;
229 }
231 late_initcall(software_resume);
234 static const char * const pm_disk_modes[] = {
235 [PM_DISK_FIRMWARE] = "firmware",
236 [PM_DISK_PLATFORM] = "platform",
237 [PM_DISK_SHUTDOWN] = "shutdown",
238 [PM_DISK_REBOOT] = "reboot",
239 };
241 /**
242 * disk - Control suspend-to-disk mode
243 *
244 * Suspend-to-disk can be handled in several ways. The greatest
245 * distinction is who writes memory to disk - the firmware or the OS.
246 * If the firmware does it, we assume that it also handles suspending
247 * the system.
248 * If the OS does it, then we have three options for putting the system
249 * to sleep - using the platform driver (e.g. ACPI or other PM registers),
250 * powering off the system or rebooting the system (for testing).
251 *
252 * The system will support either 'firmware' or 'platform', and that is
253 * known a priori (and encoded in pm_ops). But, the user may choose
254 * 'shutdown' or 'reboot' as alternatives.
255 *
256 * show() will display what the mode is currently set to.
257 * store() will accept one of
258 *
259 * 'firmware'
260 * 'platform'
261 * 'shutdown'
262 * 'reboot'
263 *
264 * It will only change to 'firmware' or 'platform' if the system
265 * supports it (as determined from pm_ops->pm_disk_mode).
266 */
268 static ssize_t disk_show(struct subsystem * subsys, char * buf)
269 {
270 return sprintf(buf, "%s\n", pm_disk_modes[pm_disk_mode]);
271 }
274 static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
275 {
276 int error = 0;
277 int i;
278 int len;
279 char *p;
280 suspend_disk_method_t mode = 0;
282 p = memchr(buf, '\n', n);
283 len = p ? p - buf : n;
285 down(&pm_sem);
286 for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
287 if (!strncmp(buf, pm_disk_modes[i], len)) {
288 mode = i;
289 break;
290 }
291 }
292 if (mode) {
293 if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
294 pm_disk_mode = mode;
295 else {
296 if (pm_ops && pm_ops->enter &&
297 (mode == pm_ops->pm_disk_mode))
298 pm_disk_mode = mode;
299 else
300 error = -EINVAL;
301 }
302 } else
303 error = -EINVAL;
305 pr_debug("PM: suspend-to-disk mode set to '%s'\n",
306 pm_disk_modes[mode]);
307 up(&pm_sem);
308 return error ? error : n;
309 }
311 power_attr(disk);
313 static ssize_t resume_show(struct subsystem * subsys, char *buf)
314 {
315 return sprintf(buf,"%d:%d\n", MAJOR(swsusp_resume_device),
316 MINOR(swsusp_resume_device));
317 }
319 static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
320 {
321 unsigned int maj, min;
322 dev_t res;
323 int ret = -EINVAL;
325 if (sscanf(buf, "%u:%u", &maj, &min) != 2)
326 goto out;
328 res = MKDEV(maj,min);
329 if (maj != MAJOR(res) || min != MINOR(res))
330 goto out;
332 down(&pm_sem);
333 swsusp_resume_device = res;
334 up(&pm_sem);
335 printk("Attempting manual resume\n");
336 noresume = 0;
337 software_resume();
338 ret = n;
339 out:
340 return ret;
341 }
343 power_attr(resume);
345 static ssize_t image_size_show(struct subsystem * subsys, char *buf)
346 {
347 return sprintf(buf, "%lu\n", image_size);
348 }
350 static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
351 {
352 unsigned long size;
354 if (sscanf(buf, "%lu", &size) == 1) {
355 image_size = size;
356 return n;
357 }
359 return -EINVAL;
360 }
362 power_attr(image_size);
364 static struct attribute * g[] = {
365 &disk_attr.attr,
366 &resume_attr.attr,
367 &image_size_attr.attr,
368 NULL,
369 };
372 static struct attribute_group attr_group = {
373 .attrs = g,
374 };
377 static int __init pm_disk_init(void)
378 {
379 return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
380 }
382 core_initcall(pm_disk_init);
385 static int __init resume_setup(char *str)
386 {
387 if (noresume)
388 return 1;
390 strncpy( resume_file, str, 255 );
391 return 1;
392 }
394 static int __init noresume_setup(char *str)
395 {
396 noresume = 1;
397 return 1;
398 }
400 __setup("noresume", noresume_setup);
401 __setup("resume=", resume_setup);