pm.h revision e7ecb331e11d1f7aa66aeef9170fc20781c9bb55
1/* 2 * pm.h - Power management interface 3 * 4 * Copyright (C) 2000 Andrew Henroid 5 * 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. 10 * 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. 15 * 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 19 */ 20 21#ifndef _LINUX_PM_H 22#define _LINUX_PM_H 23 24#include <linux/list.h> 25#include <asm/atomic.h> 26#include <asm/errno.h> 27 28/* 29 * Callbacks for platform drivers to implement. 30 */ 31extern void (*pm_idle)(void); 32extern void (*pm_power_off)(void); 33extern void (*pm_power_off_prepare)(void); 34 35/* 36 * Device power management 37 */ 38 39struct device; 40 41typedef struct pm_message { 42 int event; 43} pm_message_t; 44 45/** 46 * struct pm_ops - device PM callbacks 47 * 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). 54 * 55 * The externally visible transitions are handled with the help of the following 56 * callbacks included in this structure: 57 * 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 78 * freezing of tasks.] 79 * 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 86 * suspend earlier). 87 * The PM core executes @complete() after it has executed the appropriate 88 * resume callback for all devices. 89 * 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. 94 * 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(). 104 * 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. 112 * 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(). 118 * 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 122 * appropriate. 123 * 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(). 130 * 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. 141 * 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. 145 */ 146 147struct pm_ops { 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); 156}; 157 158/** 159 * struct pm_ext_ops - extended device PM callbacks 160 * 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 164 * 'struct pm_ops'. 165 * 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. 170 * 171 * @suspend_noirq: Complete the operations of ->suspend() by carrying out any 172 * actions required for suspending the device that need interrupts to be 173 * disabled 174 * 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 177 * disabled 178 * 179 * @freeze_noirq: Complete the operations of ->freeze() by carrying out any 180 * actions required for freezing the device that need interrupts to be 181 * disabled 182 * 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 185 * disabled 186 * 187 * @poweroff_noirq: Complete the operations of ->poweroff() by carrying out any 188 * actions required for handling the device that need interrupts to be 189 * disabled 190 * 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 194 * 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. 203 */ 204 205struct pm_ext_ops { 206 struct pm_ops base; 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); 213}; 214 215/** 216 * PM_EVENT_ messages 217 * 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 221 * code: 222 * 223 * ON No transition. 224 * 225 * FREEZE System is going to hibernate, call ->prepare() and ->freeze() 226 * for all devices. 227 * 228 * SUSPEND System is going to suspend, call ->prepare() and ->suspend() 229 * for all devices. 230 * 231 * HIBERNATE Hibernation image has been saved, call ->prepare() and 232 * ->poweroff() for all devices. 233 * 234 * QUIESCE Contents of main memory are going to be restored from a (loaded) 235 * hibernation image, call ->prepare() and ->freeze() for all 236 * devices. 237 * 238 * RESUME System is resuming, call ->resume() and ->complete() for all 239 * devices. 240 * 241 * THAW Hibernation image has been created, call ->thaw() and 242 * ->complete() for all devices. 243 * 244 * RESTORE Contents of main memory have been restored from a hibernation 245 * image, call ->restore() and ->complete() for all devices. 246 * 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. 250 */ 251 252#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 261 262#define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE) 263 264#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, }) 273 274/** 275 * Device power management states 276 * 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. 279 * 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. 283 * 284 * DPM_PREPARING Device is going to be prepared for a PM transition. Set 285 * when ->prepare() is about to be called. 286 * 287 * DPM_RESUMING Device is going to be resumed. Set when ->resume(), 288 * ->thaw(), or ->restore() is about to be called. 289 * 290 * DPM_SUSPENDING Device has been prepared for a power transition. Set 291 * when ->prepare() has just succeeded. 292 * 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. 297 * 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. 301 */ 302 303enum dpm_state { 304 DPM_INVALID, 305 DPM_ON, 306 DPM_PREPARING, 307 DPM_RESUMING, 308 DPM_SUSPENDING, 309 DPM_OFF, 310 DPM_OFF_IRQ, 311}; 312 313struct dev_pm_info { 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; 320#endif 321}; 322 323/* 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. 327 */ 328 329/* Necessary, because several drivers use PM_EVENT_PRETHAW */ 330#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE 331 332/* 333 * One transition is triggered by resume(), after a suspend() call; the 334 * message is implicit: 335 * 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(). 342 * 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: 349 * 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. 353 * 354 * HIBERNATE Enter a low power device state appropriate for the hibernation 355 * state (eg. ACPI S4) and enable wakeup events as appropriate. 356 * 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. 360 * 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. 366 * 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. 370 * 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. 375 */ 376 377#ifdef CONFIG_PM_SLEEP 378extern void device_pm_lock(void); 379extern void device_power_up(pm_message_t state); 380extern void device_resume(pm_message_t state); 381 382extern void device_pm_unlock(void); 383extern int device_power_down(pm_message_t state); 384extern int device_suspend(pm_message_t state); 385extern int device_prepare_suspend(pm_message_t state); 386 387extern void __suspend_report_result(const char *function, void *fn, int ret); 388 389#define suspend_report_result(fn, ret) \ 390 do { \ 391 __suspend_report_result(__FUNCTION__, fn, ret); \ 392 } while (0) 393 394#else /* !CONFIG_PM_SLEEP */ 395 396static inline int device_suspend(pm_message_t state) 397{ 398 return 0; 399} 400 401#define suspend_report_result(fn, ret) do {} while (0) 402 403#endif /* !CONFIG_PM_SLEEP */ 404 405/* 406 * Global Power Management flags 407 * Used to keep APM and ACPI from both being active 408 */ 409extern unsigned int pm_flags; 410 411#define PM_APM 1 412#define PM_ACPI 2 413 414#endif /* _LINUX_PM_H */ 415