2 * pm.h - Power management interface
4 * Copyright (C) 2000 Andrew Henroid
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/list.h>
25 #include <asm/atomic.h>
26 #include <asm/errno.h>
29 * Callbacks for platform drivers to implement.
31 extern void (*pm_idle)(void);
32 extern void (*pm_power_off)(void);
33 extern void (*pm_power_off_prepare)(void);
36 * Device power management
41 typedef struct pm_message {
46 * struct pm_ops - device PM callbacks
48 * Several driver power state transitions are externally visible, affecting
49 * the state of pending I/O queues and (for drivers that touch hardware)
50 * interrupts, wakeups, DMA, and other hardware state. There may also be
51 * internal transitions to various low power modes, which are transparent
52 * to the rest of the driver stack (such as a driver that's ON gating off
53 * clocks which are not in active use).
55 * The externally visible transitions are handled with the help of the following
56 * callbacks included in this structure:
58 * @prepare: Prepare the device for the upcoming transition, but do NOT change
59 * its hardware state. Prevent new children of the device from being
60 * registered after @prepare() returns (the driver's subsystem and
61 * generally the rest of the kernel is supposed to prevent new calls to the
62 * probe method from being made too once @prepare() has succeeded). If
63 * @prepare() detects a situation it cannot handle (e.g. registration of a
64 * child already in progress), it may return -EAGAIN, so that the PM core
65 * can execute it once again (e.g. after the new child has been registered)
66 * to recover from the race condition. This method is executed for all
67 * kinds of suspend transitions and is followed by one of the suspend
68 * callbacks: @suspend(), @freeze(), or @poweroff().
69 * The PM core executes @prepare() for all devices before starting to
70 * execute suspend callbacks for any of them, so drivers may assume all of
71 * the other devices to be present and functional while @prepare() is being
72 * executed. In particular, it is safe to make GFP_KERNEL memory
73 * allocations from within @prepare(). However, drivers may NOT assume
74 * anything about the availability of the user space at that time and it
75 * is not correct to request firmware from within @prepare() (it's too
76 * late to do that). [To work around this limitation, drivers may
77 * register suspend and hibernation notifiers that are executed before the
80 * @complete: Undo the changes made by @prepare(). This method is executed for
81 * all kinds of resume transitions, following one of the resume callbacks:
82 * @resume(), @thaw(), @restore(). Also called if the state transition
83 * fails before the driver's suspend callback (@suspend(), @freeze(),
84 * @poweroff()) can be executed (e.g. if the suspend callback fails for one
85 * of the other devices that the PM core has unsuccessfully attempted to
87 * The PM core executes @complete() after it has executed the appropriate
88 * resume callback for all devices.
90 * @suspend: Executed before putting the system into a sleep state in which the
91 * contents of main memory are preserved. Quiesce the device, put it into
92 * a low power state appropriate for the upcoming system state (such as
93 * PCI_D3hot), and enable wakeup events as appropriate.
95 * @resume: Executed after waking the system up from a sleep state in which the
96 * contents of main memory were preserved. Put the device into the
97 * appropriate state, according to the information saved in memory by the
98 * preceding @suspend(). The driver starts working again, responding to
99 * hardware events and software requests. The hardware may have gone
100 * through a power-off reset, or it may have maintained state from the
101 * previous suspend() which the driver may rely on while resuming. On most
102 * platforms, there are no restrictions on availability of resources like
103 * clocks during @resume().
105 * @freeze: Hibernation-specific, executed before creating a hibernation image.
106 * Quiesce operations so that a consistent image can be created, but do NOT
107 * otherwise put the device into a low power device state and do NOT emit
108 * system wakeup events. Save in main memory the device settings to be
109 * used by @restore() during the subsequent resume from hibernation or by
110 * the subsequent @thaw(), if the creation of the image or the restoration
111 * of main memory contents from it fails.
113 * @thaw: Hibernation-specific, executed after creating a hibernation image OR
114 * if the creation of the image fails. Also executed after a failing
115 * attempt to restore the contents of main memory from such an image.
116 * Undo the changes made by the preceding @freeze(), so the device can be
117 * operated in the same way as immediately before the call to @freeze().
119 * @poweroff: Hibernation-specific, executed after saving a hibernation image.
120 * Quiesce the device, put it into a low power state appropriate for the
121 * upcoming system state (such as PCI_D3hot), and enable wakeup events as
124 * @restore: Hibernation-specific, executed after restoring the contents of main
125 * memory from a hibernation image. Driver starts working again,
126 * responding to hardware events and software requests. Drivers may NOT
127 * make ANY assumptions about the hardware state right prior to @restore().
128 * On most platforms, there are no restrictions on availability of
129 * resources like clocks during @restore().
131 * All of the above callbacks, except for @complete(), return error codes.
132 * However, the error codes returned by the resume operations, @resume(),
133 * @thaw(), and @restore(), do not cause the PM core to abort the resume
134 * transition during which they are returned. The error codes returned in
135 * that cases are only printed by the PM core to the system logs for debugging
136 * purposes. Still, it is recommended that drivers only return error codes
137 * from their resume methods in case of an unrecoverable failure (i.e. when the
138 * device being handled refuses to resume and becomes unusable) to allow us to
139 * modify the PM core in the future, so that it can avoid attempting to handle
140 * devices that failed to resume and their children.
142 * It is allowed to unregister devices while the above callbacks are being
143 * executed. However, it is not allowed to unregister a device from within any
144 * of its own callbacks.
148 int (*prepare)(struct device *dev);
149 void (*complete)(struct device *dev);
150 int (*suspend)(struct device *dev);
151 int (*resume)(struct device *dev);
152 int (*freeze)(struct device *dev);
153 int (*thaw)(struct device *dev);
154 int (*poweroff)(struct device *dev);
155 int (*restore)(struct device *dev);
159 * struct pm_ext_ops - extended device PM callbacks
161 * Some devices require certain operations related to suspend and hibernation
162 * to be carried out with interrupts disabled. Thus, 'struct pm_ext_ops' below
163 * is defined, adding callbacks to be executed with interrupts disabled to
166 * The following callbacks included in 'struct pm_ext_ops' are executed with
167 * the nonboot CPUs switched off and with interrupts disabled on the only
168 * functional CPU. They also are executed with the PM core list of devices
169 * locked, so they must NOT unregister any devices.
171 * @suspend_noirq: Complete the operations of ->suspend() by carrying out any
172 * actions required for suspending the device that need interrupts to be
175 * @resume_noirq: Prepare for the execution of ->resume() by carrying out any
176 * actions required for resuming the device that need interrupts to be
179 * @freeze_noirq: Complete the operations of ->freeze() by carrying out any
180 * actions required for freezing the device that need interrupts to be
183 * @thaw_noirq: Prepare for the execution of ->thaw() by carrying out any
184 * actions required for thawing the device that need interrupts to be
187 * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any
188 * actions required for handling the device that need interrupts to be
191 * @restore_noirq: Prepare for the execution of ->restore() by carrying out any
192 * actions required for restoring the operations of the device that need
193 * interrupts to be disabled
195 * All of the above callbacks return error codes, but the error codes returned
196 * by the resume operations, @resume_noirq(), @thaw_noirq(), and
197 * @restore_noirq(), do not cause the PM core to abort the resume transition
198 * during which they are returned. The error codes returned in that cases are
199 * only printed by the PM core to the system logs for debugging purposes.
200 * Still, as stated above, it is recommended that drivers only return error
201 * codes from their resume methods if the device being handled fails to resume
202 * and is not usable any more.
207 int (*suspend_noirq)(struct device *dev);
208 int (*resume_noirq)(struct device *dev);
209 int (*freeze_noirq)(struct device *dev);
210 int (*thaw_noirq)(struct device *dev);
211 int (*poweroff_noirq)(struct device *dev);
212 int (*restore_noirq)(struct device *dev);
218 * The following PM_EVENT_ messages are defined for the internal use of the PM
219 * core, in order to provide a mechanism allowing the high level suspend and
220 * hibernation code to convey the necessary information to the device PM core
225 * FREEZE System is going to hibernate, call ->prepare() and ->freeze()
228 * SUSPEND System is going to suspend, call ->prepare() and ->suspend()
231 * HIBERNATE Hibernation image has been saved, call ->prepare() and
232 * ->poweroff() for all devices.
234 * QUIESCE Contents of main memory are going to be restored from a (loaded)
235 * hibernation image, call ->prepare() and ->freeze() for all
238 * RESUME System is resuming, call ->resume() and ->complete() for all
241 * THAW Hibernation image has been created, call ->thaw() and
242 * ->complete() for all devices.
244 * RESTORE Contents of main memory have been restored from a hibernation
245 * image, call ->restore() and ->complete() for all devices.
247 * RECOVER Creation of a hibernation image or restoration of the main
248 * memory contents from a hibernation image has failed, call
249 * ->thaw() and ->complete() for all devices.
252 #define PM_EVENT_ON 0x0000
253 #define PM_EVENT_FREEZE 0x0001
254 #define PM_EVENT_SUSPEND 0x0002
255 #define PM_EVENT_HIBERNATE 0x0004
256 #define PM_EVENT_QUIESCE 0x0008
257 #define PM_EVENT_RESUME 0x0010
258 #define PM_EVENT_THAW 0x0020
259 #define PM_EVENT_RESTORE 0x0040
260 #define PM_EVENT_RECOVER 0x0080
262 #define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE)
264 #define PMSG_FREEZE ((struct pm_message){ .event = PM_EVENT_FREEZE, })
265 #define PMSG_QUIESCE ((struct pm_message){ .event = PM_EVENT_QUIESCE, })
266 #define PMSG_SUSPEND ((struct pm_message){ .event = PM_EVENT_SUSPEND, })
267 #define PMSG_HIBERNATE ((struct pm_message){ .event = PM_EVENT_HIBERNATE, })
268 #define PMSG_RESUME ((struct pm_message){ .event = PM_EVENT_RESUME, })
269 #define PMSG_THAW ((struct pm_message){ .event = PM_EVENT_THAW, })
270 #define PMSG_RESTORE ((struct pm_message){ .event = PM_EVENT_RESTORE, })
271 #define PMSG_RECOVER ((struct pm_message){ .event = PM_EVENT_RECOVER, })
272 #define PMSG_ON ((struct pm_message){ .event = PM_EVENT_ON, })
275 * Device power management states
277 * These state labels are used internally by the PM core to indicate the current
278 * status of a device with respect to the PM core operations.
280 * DPM_ON Device is regarded as operational. Set this way
281 * initially and when ->complete() is about to be called.
282 * Also set when ->prepare() fails.
284 * DPM_PREPARING Device is going to be prepared for a PM transition. Set
285 * when ->prepare() is about to be called.
287 * DPM_RESUMING Device is going to be resumed. Set when ->resume(),
288 * ->thaw(), or ->restore() is about to be called.
290 * DPM_SUSPENDING Device has been prepared for a power transition. Set
291 * when ->prepare() has just succeeded.
293 * DPM_OFF Device is regarded as inactive. Set immediately after
294 * ->suspend(), ->freeze(), or ->poweroff() has succeeded.
295 * Also set when ->resume()_noirq, ->thaw_noirq(), or
296 * ->restore_noirq() is about to be called.
298 * DPM_OFF_IRQ Device is in a "deep sleep". Set immediately after
299 * ->suspend_noirq(), ->freeze_noirq(), or
300 * ->poweroff_noirq() has just succeeded.
314 pm_message_t power_state;
315 unsigned can_wakeup:1;
316 unsigned should_wakeup:1;
317 enum dpm_state status; /* Owned by the PM core */
318 #ifdef CONFIG_PM_SLEEP
319 struct list_head entry;
324 * The PM_EVENT_ messages are also used by drivers implementing the legacy
325 * suspend framework, based on the ->suspend() and ->resume() callbacks common
326 * for suspend and hibernation transitions, according to the rules below.
329 /* Necessary, because several drivers use PM_EVENT_PRETHAW */
330 #define PM_EVENT_PRETHAW PM_EVENT_QUIESCE
333 * One transition is triggered by resume(), after a suspend() call; the
334 * message is implicit:
336 * ON Driver starts working again, responding to hardware events
337 * and software requests. The hardware may have gone through
338 * a power-off reset, or it may have maintained state from the
339 * previous suspend() which the driver will rely on while
340 * resuming. On most platforms, there are no restrictions on
341 * availability of resources like clocks during resume().
343 * Other transitions are triggered by messages sent using suspend(). All
344 * these transitions quiesce the driver, so that I/O queues are inactive.
345 * That commonly entails turning off IRQs and DMA; there may be rules
346 * about how to quiesce that are specific to the bus or the device's type.
347 * (For example, network drivers mark the link state.) Other details may
348 * differ according to the message:
350 * SUSPEND Quiesce, enter a low power device state appropriate for
351 * the upcoming system state (such as PCI_D3hot), and enable
352 * wakeup events as appropriate.
354 * HIBERNATE Enter a low power device state appropriate for the hibernation
355 * state (eg. ACPI S4) and enable wakeup events as appropriate.
357 * FREEZE Quiesce operations so that a consistent image can be saved;
358 * but do NOT otherwise enter a low power device state, and do
359 * NOT emit system wakeup events.
361 * PRETHAW Quiesce as if for FREEZE; additionally, prepare for restoring
362 * the system from a snapshot taken after an earlier FREEZE.
363 * Some drivers will need to reset their hardware state instead
364 * of preserving it, to ensure that it's never mistaken for the
365 * state which that earlier snapshot had set up.
367 * A minimally power-aware driver treats all messages as SUSPEND, fully
368 * reinitializes its device during resume() -- whether or not it was reset
369 * during the suspend/resume cycle -- and can't issue wakeup events.
371 * More power-aware drivers may also use low power states at runtime as
372 * well as during system sleep states like PM_SUSPEND_STANDBY. They may
373 * be able to use wakeup events to exit from runtime low-power states,
374 * or from system low-power states such as standby or suspend-to-RAM.
377 #ifdef CONFIG_PM_SLEEP
378 extern void device_pm_lock(void);
379 extern void device_power_up(pm_message_t state);
380 extern void device_resume(pm_message_t state);
382 extern void device_pm_unlock(void);
383 extern int device_power_down(pm_message_t state);
384 extern int device_suspend(pm_message_t state);
385 extern int device_prepare_suspend(pm_message_t state);
387 extern void __suspend_report_result(const char *function, void *fn, int ret);
389 #define suspend_report_result(fn, ret) \
391 __suspend_report_result(__FUNCTION__, fn, ret); \
394 #else /* !CONFIG_PM_SLEEP */
396 static inline int device_suspend(pm_message_t state)
401 #define suspend_report_result(fn, ret) do {} while (0)
403 #endif /* !CONFIG_PM_SLEEP */
406 * Global Power Management flags
407 * Used to keep APM and ACPI from both being active
409 extern unsigned int pm_flags;
414 #endif /* _LINUX_PM_H */