ia64/linux-2.6.18-xen.hg

view kernel/power/main.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/main.c - PM subsystem core functionality.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 *
7 * This file is released under the GPLv2
8 *
9 */
11 #include <linux/suspend.h>
12 #include <linux/kobject.h>
13 #include <linux/string.h>
14 #include <linux/delay.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
17 #include <linux/pm.h>
18 #include <linux/console.h>
20 #include "power.h"
22 /*This is just an arbitrary number */
23 #define FREE_PAGE_NUMBER (100)
25 DECLARE_MUTEX(pm_sem);
27 struct pm_ops *pm_ops;
28 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
30 /**
31 * pm_set_ops - Set the global power method table.
32 * @ops: Pointer to ops structure.
33 */
35 void pm_set_ops(struct pm_ops * ops)
36 {
37 down(&pm_sem);
38 pm_ops = ops;
39 up(&pm_sem);
40 }
43 /**
44 * suspend_prepare - Do prep work before entering low-power state.
45 * @state: State we're entering.
46 *
47 * This is common code that is called for each state that we're
48 * entering. Allocate a console, stop all processes, then make sure
49 * the platform can enter the requested state.
50 */
52 static int suspend_prepare(suspend_state_t state)
53 {
54 int error = 0;
55 unsigned int free_pages;
57 if (!pm_ops || !pm_ops->enter)
58 return -EPERM;
60 pm_prepare_console();
62 disable_nonboot_cpus();
64 if (num_online_cpus() != 1) {
65 error = -EPERM;
66 goto Enable_cpu;
67 }
69 if (freeze_processes()) {
70 error = -EAGAIN;
71 goto Thaw;
72 }
74 if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
75 pr_debug("PM: free some memory\n");
76 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
77 if (nr_free_pages() < FREE_PAGE_NUMBER) {
78 error = -ENOMEM;
79 printk(KERN_ERR "PM: No enough memory\n");
80 goto Thaw;
81 }
82 }
84 if (pm_ops->prepare) {
85 if ((error = pm_ops->prepare(state)))
86 goto Thaw;
87 }
89 suspend_console();
90 if ((error = device_suspend(PMSG_SUSPEND))) {
91 printk(KERN_ERR "Some devices failed to suspend\n");
92 goto Finish;
93 }
94 return 0;
95 Finish:
96 if (pm_ops->finish)
97 pm_ops->finish(state);
98 Thaw:
99 thaw_processes();
100 Enable_cpu:
101 enable_nonboot_cpus();
102 pm_restore_console();
103 return error;
104 }
107 int suspend_enter(suspend_state_t state)
108 {
109 int error = 0;
110 unsigned long flags;
112 local_irq_save(flags);
114 if ((error = device_power_down(PMSG_SUSPEND))) {
115 printk(KERN_ERR "Some devices failed to power down\n");
116 goto Done;
117 }
118 error = pm_ops->enter(state);
119 device_power_up();
120 Done:
121 local_irq_restore(flags);
122 return error;
123 }
126 /**
127 * suspend_finish - Do final work before exiting suspend sequence.
128 * @state: State we're coming out of.
129 *
130 * Call platform code to clean up, restart processes, and free the
131 * console that we've allocated. This is not called for suspend-to-disk.
132 */
134 static void suspend_finish(suspend_state_t state)
135 {
136 device_resume();
137 resume_console();
138 thaw_processes();
139 enable_nonboot_cpus();
140 if (pm_ops && pm_ops->finish)
141 pm_ops->finish(state);
142 pm_restore_console();
143 }
148 static const char * const pm_states[PM_SUSPEND_MAX] = {
149 [PM_SUSPEND_STANDBY] = "standby",
150 [PM_SUSPEND_MEM] = "mem",
151 #ifdef CONFIG_SOFTWARE_SUSPEND
152 [PM_SUSPEND_DISK] = "disk",
153 #endif
154 };
156 static inline int valid_state(suspend_state_t state)
157 {
158 /* Suspend-to-disk does not really need low-level support.
159 * It can work with reboot if needed. */
160 if (state == PM_SUSPEND_DISK)
161 return 1;
163 if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
164 return 0;
165 return 1;
166 }
169 /**
170 * enter_state - Do common work of entering low-power state.
171 * @state: pm_state structure for state we're entering.
172 *
173 * Make sure we're the only ones trying to enter a sleep state. Fail
174 * if someone has beat us to it, since we don't want anything weird to
175 * happen when we wake up.
176 * Then, do the setup for suspend, enter the state, and cleaup (after
177 * we've woken up).
178 */
180 static int enter_state(suspend_state_t state)
181 {
182 int error;
184 if (!valid_state(state))
185 return -ENODEV;
186 if (down_trylock(&pm_sem))
187 return -EBUSY;
189 if (state == PM_SUSPEND_DISK) {
190 error = pm_suspend_disk();
191 goto Unlock;
192 }
194 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
195 if ((error = suspend_prepare(state)))
196 goto Unlock;
198 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
199 error = suspend_enter(state);
201 pr_debug("PM: Finishing wakeup.\n");
202 suspend_finish(state);
203 Unlock:
204 up(&pm_sem);
205 return error;
206 }
208 /*
209 * This is main interface to the outside world. It needs to be
210 * called from process context.
211 */
212 int software_suspend(void)
213 {
214 return enter_state(PM_SUSPEND_DISK);
215 }
218 /**
219 * pm_suspend - Externally visible function for suspending system.
220 * @state: Enumarted value of state to enter.
221 *
222 * Determine whether or not value is within range, get state
223 * structure, and enter (above).
224 */
226 int pm_suspend(suspend_state_t state)
227 {
228 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
229 return enter_state(state);
230 return -EINVAL;
231 }
235 decl_subsys(power,NULL,NULL);
238 /**
239 * state - control system power state.
240 *
241 * show() returns what states are supported, which is hard-coded to
242 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
243 * 'disk' (Suspend-to-Disk).
244 *
245 * store() accepts one of those strings, translates it into the
246 * proper enumerated value, and initiates a suspend transition.
247 */
249 static ssize_t state_show(struct subsystem * subsys, char * buf)
250 {
251 int i;
252 char * s = buf;
254 for (i = 0; i < PM_SUSPEND_MAX; i++) {
255 if (pm_states[i] && valid_state(i))
256 s += sprintf(s,"%s ", pm_states[i]);
257 }
258 s += sprintf(s,"\n");
259 return (s - buf);
260 }
262 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
263 {
264 suspend_state_t state = PM_SUSPEND_STANDBY;
265 const char * const *s;
266 char *p;
267 int error;
268 int len;
270 p = memchr(buf, '\n', n);
271 len = p ? p - buf : n;
273 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
274 if (*s && !strncmp(buf, *s, len))
275 break;
276 }
277 if (state < PM_SUSPEND_MAX && *s)
278 error = enter_state(state);
279 else
280 error = -EINVAL;
281 return error ? error : n;
282 }
284 power_attr(state);
286 static struct attribute * g[] = {
287 &state_attr.attr,
288 NULL,
289 };
291 static struct attribute_group attr_group = {
292 .attrs = g,
293 };
296 static int __init pm_init(void)
297 {
298 int error = subsystem_register(&power_subsys);
299 if (!error)
300 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
301 return error;
302 }
304 core_initcall(pm_init);