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 <linux/workqueue.h> 26 #include <linux/spinlock.h> 27 #include <linux/wait.h> 28 #include <linux/timer.h> 29 #include <linux/completion.h> 30 31 /* 32 * Callbacks for platform drivers to implement. 33 */ 34 extern void (*pm_idle)(void); 35 extern void (*pm_power_off)(void); 36 extern void (*pm_power_off_prepare)(void); 37 38 /* 39 * Device power management 40 */ 41 42 struct device; 43 44 #ifdef CONFIG_PM 45 extern const char power_group_name[]; /* = "power" */ 46 #else 47 #define power_group_name NULL 48 #endif 49 50 typedef struct pm_message { 51 int event; 52 } pm_message_t; 53 54 /** 55 * struct dev_pm_ops - device PM callbacks 56 * 57 * Several device power state transitions are externally visible, affecting 58 * the state of pending I/O queues and (for drivers that touch hardware) 59 * interrupts, wakeups, DMA, and other hardware state. There may also be 60 * internal transitions to various low-power modes which are transparent 61 * to the rest of the driver stack (such as a driver that's ON gating off 62 * clocks which are not in active use). 63 * 64 * The externally visible transitions are handled with the help of callbacks 65 * included in this structure in such a way that two levels of callbacks are 66 * involved. First, the PM core executes callbacks provided by PM domains, 67 * device types, classes and bus types. They are the subsystem-level callbacks 68 * supposed to execute callbacks provided by device drivers, although they may 69 * choose not to do that. If the driver callbacks are executed, they have to 70 * collaborate with the subsystem-level callbacks to achieve the goals 71 * appropriate for the given system transition, given transition phase and the 72 * subsystem the device belongs to. 73 * 74 * @prepare: The principal role of this callback is to prevent new children of 75 * the device from being registered after it has returned (the driver's 76 * subsystem and generally the rest of the kernel is supposed to prevent 77 * new calls to the probe method from being made too once @prepare() has 78 * succeeded). If @prepare() detects a situation it cannot handle (e.g. 79 * registration of a child already in progress), it may return -EAGAIN, so 80 * that the PM core can execute it once again (e.g. after a new child has 81 * been registered) to recover from the race condition. 82 * This method is executed for all kinds of suspend transitions and is 83 * followed by one of the suspend callbacks: @suspend(), @freeze(), or 84 * @poweroff(). The PM core executes subsystem-level @prepare() for all 85 * devices before starting to invoke suspend callbacks for any of them, so 86 * generally devices may be assumed to be functional or to respond to 87 * runtime resume requests while @prepare() is being executed. However, 88 * device drivers may NOT assume anything about the availability of user 89 * space at that time and it is NOT valid to request firmware from within 90 * @prepare() (it's too late to do that). It also is NOT valid to allocate 91 * substantial amounts of memory from @prepare() in the GFP_KERNEL mode. 92 * [To work around these limitations, drivers may register suspend and 93 * hibernation notifiers to be executed before the freezing of tasks.] 94 * 95 * @complete: Undo the changes made by @prepare(). This method is executed for 96 * all kinds of resume transitions, following one of the resume callbacks: 97 * @resume(), @thaw(), @restore(). Also called if the state transition 98 * fails before the driver's suspend callback: @suspend(), @freeze() or 99 * @poweroff(), can be executed (e.g. if the suspend callback fails for one 100 * of the other devices that the PM core has unsuccessfully attempted to 101 * suspend earlier). 102 * The PM core executes subsystem-level @complete() after it has executed 103 * the appropriate resume callbacks for all devices. 104 * 105 * @suspend: Executed before putting the system into a sleep state in which the 106 * contents of main memory are preserved. The exact action to perform 107 * depends on the device's subsystem (PM domain, device type, class or bus 108 * type), but generally the device must be quiescent after subsystem-level 109 * @suspend() has returned, so that it doesn't do any I/O or DMA. 110 * Subsystem-level @suspend() is executed for all devices after invoking 111 * subsystem-level @prepare() for all of them. 112 * 113 * @resume: Executed after waking the system up from a sleep state in which the 114 * contents of main memory were preserved. The exact action to perform 115 * depends on the device's subsystem, but generally the driver is expected 116 * to start working again, responding to hardware events and software 117 * requests (the device itself may be left in a low-power state, waiting 118 * for a runtime resume to occur). The state of the device at the time its 119 * driver's @resume() callback is run depends on the platform and subsystem 120 * the device belongs to. On most platforms, there are no restrictions on 121 * availability of resources like clocks during @resume(). 122 * Subsystem-level @resume() is executed for all devices after invoking 123 * subsystem-level @resume_noirq() for all of them. 124 * 125 * @freeze: Hibernation-specific, executed before creating a hibernation image. 126 * Analogous to @suspend(), but it should not enable the device to signal 127 * wakeup events or change its power state. The majority of subsystems 128 * (with the notable exception of the PCI bus type) expect the driver-level 129 * @freeze() to save the device settings in memory to be used by @restore() 130 * during the subsequent resume from hibernation. 131 * Subsystem-level @freeze() is executed for all devices after invoking 132 * subsystem-level @prepare() for all of them. 133 * 134 * @thaw: Hibernation-specific, executed after creating a hibernation image OR 135 * if the creation of an image has failed. Also executed after a failing 136 * attempt to restore the contents of main memory from such an image. 137 * Undo the changes made by the preceding @freeze(), so the device can be 138 * operated in the same way as immediately before the call to @freeze(). 139 * Subsystem-level @thaw() is executed for all devices after invoking 140 * subsystem-level @thaw_noirq() for all of them. It also may be executed 141 * directly after @freeze() in case of a transition error. 142 * 143 * @poweroff: Hibernation-specific, executed after saving a hibernation image. 144 * Analogous to @suspend(), but it need not save the device's settings in 145 * memory. 146 * Subsystem-level @poweroff() is executed for all devices after invoking 147 * subsystem-level @prepare() for all of them. 148 * 149 * @restore: Hibernation-specific, executed after restoring the contents of main 150 * memory from a hibernation image, analogous to @resume(). 151 * 152 * @suspend_noirq: Complete the actions started by @suspend(). Carry out any 153 * additional operations required for suspending the device that might be 154 * racing with its driver's interrupt handler, which is guaranteed not to 155 * run while @suspend_noirq() is being executed. 156 * It generally is expected that the device will be in a low-power state 157 * (appropriate for the target system sleep state) after subsystem-level 158 * @suspend_noirq() has returned successfully. If the device can generate 159 * system wakeup signals and is enabled to wake up the system, it should be 160 * configured to do so at that time. However, depending on the platform 161 * and device's subsystem, @suspend() may be allowed to put the device into 162 * the low-power state and configure it to generate wakeup signals, in 163 * which case it generally is not necessary to define @suspend_noirq(). 164 * 165 * @resume_noirq: Prepare for the execution of @resume() by carrying out any 166 * operations required for resuming the device that might be racing with 167 * its driver's interrupt handler, which is guaranteed not to run while 168 * @resume_noirq() is being executed. 169 * 170 * @freeze_noirq: Complete the actions started by @freeze(). Carry out any 171 * additional operations required for freezing the device that might be 172 * racing with its driver's interrupt handler, which is guaranteed not to 173 * run while @freeze_noirq() is being executed. 174 * The power state of the device should not be changed by either @freeze() 175 * or @freeze_noirq() and it should not be configured to signal system 176 * wakeup by any of these callbacks. 177 * 178 * @thaw_noirq: Prepare for the execution of @thaw() by carrying out any 179 * operations required for thawing the device that might be racing with its 180 * driver's interrupt handler, which is guaranteed not to run while 181 * @thaw_noirq() is being executed. 182 * 183 * @poweroff_noirq: Complete the actions started by @poweroff(). Analogous to 184 * @suspend_noirq(), but it need not save the device's settings in memory. 185 * 186 * @restore_noirq: Prepare for the execution of @restore() by carrying out any 187 * operations required for thawing the device that might be racing with its 188 * driver's interrupt handler, which is guaranteed not to run while 189 * @restore_noirq() is being executed. Analogous to @resume_noirq(). 190 * 191 * All of the above callbacks, except for @complete(), return error codes. 192 * However, the error codes returned by the resume operations, @resume(), 193 * @thaw(), @restore(), @resume_noirq(), @thaw_noirq(), and @restore_noirq(), do 194 * not cause the PM core to abort the resume transition during which they are 195 * returned. The error codes returned in those cases are only printed by the PM 196 * core to the system logs for debugging purposes. Still, it is recommended 197 * that drivers only return error codes from their resume methods in case of an 198 * unrecoverable failure (i.e. when the device being handled refuses to resume 199 * and becomes unusable) to allow us to modify the PM core in the future, so 200 * that it can avoid attempting to handle devices that failed to resume and 201 * their children. 202 * 203 * It is allowed to unregister devices while the above callbacks are being 204 * executed. However, a callback routine must NOT try to unregister the device 205 * it was called for, although it may unregister children of that device (for 206 * example, if it detects that a child was unplugged while the system was 207 * asleep). 208 * 209 * Refer to Documentation/power/devices.txt for more information about the role 210 * of the above callbacks in the system suspend process. 211 * 212 * There also are callbacks related to runtime power management of devices. 213 * Again, these callbacks are executed by the PM core only for subsystems 214 * (PM domains, device types, classes and bus types) and the subsystem-level 215 * callbacks are supposed to invoke the driver callbacks. Moreover, the exact 216 * actions to be performed by a device driver's callbacks generally depend on 217 * the platform and subsystem the device belongs to. 218 * 219 * @runtime_suspend: Prepare the device for a condition in which it won't be 220 * able to communicate with the CPU(s) and RAM due to power management. 221 * This need not mean that the device should be put into a low-power state. 222 * For example, if the device is behind a link which is about to be turned 223 * off, the device may remain at full power. If the device does go to low 224 * power and is capable of generating runtime wakeup events, remote wakeup 225 * (i.e., a hardware mechanism allowing the device to request a change of 226 * its power state via an interrupt) should be enabled for it. 227 * 228 * @runtime_resume: Put the device into the fully active state in response to a 229 * wakeup event generated by hardware or at the request of software. If 230 * necessary, put the device into the full-power state and restore its 231 * registers, so that it is fully operational. 232 * 233 * @runtime_idle: Device appears to be inactive and it might be put into a 234 * low-power state if all of the necessary conditions are satisfied. Check 235 * these conditions and handle the device as appropriate, possibly queueing 236 * a suspend request for it. The return value is ignored by the PM core. 237 * 238 * Refer to Documentation/power/runtime_pm.txt for more information about the 239 * role of the above callbacks in device runtime power management. 240 * 241 */ 242 243 struct dev_pm_ops { 244 int (*prepare)(struct device *dev); 245 void (*complete)(struct device *dev); 246 int (*suspend)(struct device *dev); 247 int (*resume)(struct device *dev); 248 int (*freeze)(struct device *dev); 249 int (*thaw)(struct device *dev); 250 int (*poweroff)(struct device *dev); 251 int (*restore)(struct device *dev); 252 int (*suspend_noirq)(struct device *dev); 253 int (*resume_noirq)(struct device *dev); 254 int (*freeze_noirq)(struct device *dev); 255 int (*thaw_noirq)(struct device *dev); 256 int (*poweroff_noirq)(struct device *dev); 257 int (*restore_noirq)(struct device *dev); 258 int (*runtime_suspend)(struct device *dev); 259 int (*runtime_resume)(struct device *dev); 260 int (*runtime_idle)(struct device *dev); 261 }; 262 263 #ifdef CONFIG_PM_SLEEP 264 #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ 265 .suspend = suspend_fn, \ 266 .resume = resume_fn, \ 267 .freeze = suspend_fn, \ 268 .thaw = resume_fn, \ 269 .poweroff = suspend_fn, \ 270 .restore = resume_fn, 271 #else 272 #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) 273 #endif 274 275 #ifdef CONFIG_PM_RUNTIME 276 #define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \ 277 .runtime_suspend = suspend_fn, \ 278 .runtime_resume = resume_fn, \ 279 .runtime_idle = idle_fn, 280 #else 281 #define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) 282 #endif 283 284 /* 285 * Use this if you want to use the same suspend and resume callbacks for suspend 286 * to RAM and hibernation. 287 */ 288 #define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ 289 const struct dev_pm_ops name = { \ 290 SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ 291 } 292 293 /* 294 * Use this for defining a set of PM operations to be used in all situations 295 * (sustem suspend, hibernation or runtime PM). 296 */ 297 #define UNIVERSAL_DEV_PM_OPS(name, suspend_fn, resume_fn, idle_fn) \ 298 const struct dev_pm_ops name = { \ 299 SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ 300 SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) \ 301 } 302 303 /* 304 * Use this for subsystems (bus types, device types, device classes) that don't 305 * need any special suspend/resume handling in addition to invoking the PM 306 * callbacks provided by device drivers supporting both the system sleep PM and 307 * runtime PM, make the pm member point to generic_subsys_pm_ops. 308 */ 309 #ifdef CONFIG_PM 310 extern struct dev_pm_ops generic_subsys_pm_ops; 311 #define GENERIC_SUBSYS_PM_OPS (&generic_subsys_pm_ops) 312 #else 313 #define GENERIC_SUBSYS_PM_OPS NULL 314 #endif 315 316 /** 317 * PM_EVENT_ messages 318 * 319 * The following PM_EVENT_ messages are defined for the internal use of the PM 320 * core, in order to provide a mechanism allowing the high level suspend and 321 * hibernation code to convey the necessary information to the device PM core 322 * code: 323 * 324 * ON No transition. 325 * 326 * FREEZE System is going to hibernate, call ->prepare() and ->freeze() 327 * for all devices. 328 * 329 * SUSPEND System is going to suspend, call ->prepare() and ->suspend() 330 * for all devices. 331 * 332 * HIBERNATE Hibernation image has been saved, call ->prepare() and 333 * ->poweroff() for all devices. 334 * 335 * QUIESCE Contents of main memory are going to be restored from a (loaded) 336 * hibernation image, call ->prepare() and ->freeze() for all 337 * devices. 338 * 339 * RESUME System is resuming, call ->resume() and ->complete() for all 340 * devices. 341 * 342 * THAW Hibernation image has been created, call ->thaw() and 343 * ->complete() for all devices. 344 * 345 * RESTORE Contents of main memory have been restored from a hibernation 346 * image, call ->restore() and ->complete() for all devices. 347 * 348 * RECOVER Creation of a hibernation image or restoration of the main 349 * memory contents from a hibernation image has failed, call 350 * ->thaw() and ->complete() for all devices. 351 * 352 * The following PM_EVENT_ messages are defined for internal use by 353 * kernel subsystems. They are never issued by the PM core. 354 * 355 * USER_SUSPEND Manual selective suspend was issued by userspace. 356 * 357 * USER_RESUME Manual selective resume was issued by userspace. 358 * 359 * REMOTE_WAKEUP Remote-wakeup request was received from the device. 360 * 361 * AUTO_SUSPEND Automatic (device idle) runtime suspend was 362 * initiated by the subsystem. 363 * 364 * AUTO_RESUME Automatic (device needed) runtime resume was 365 * requested by a driver. 366 */ 367 368 #define PM_EVENT_INVALID (-1) 369 #define PM_EVENT_ON 0x0000 370 #define PM_EVENT_FREEZE 0x0001 371 #define PM_EVENT_SUSPEND 0x0002 372 #define PM_EVENT_HIBERNATE 0x0004 373 #define PM_EVENT_QUIESCE 0x0008 374 #define PM_EVENT_RESUME 0x0010 375 #define PM_EVENT_THAW 0x0020 376 #define PM_EVENT_RESTORE 0x0040 377 #define PM_EVENT_RECOVER 0x0080 378 #define PM_EVENT_USER 0x0100 379 #define PM_EVENT_REMOTE 0x0200 380 #define PM_EVENT_AUTO 0x0400 381 382 #define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE) 383 #define PM_EVENT_USER_SUSPEND (PM_EVENT_USER | PM_EVENT_SUSPEND) 384 #define PM_EVENT_USER_RESUME (PM_EVENT_USER | PM_EVENT_RESUME) 385 #define PM_EVENT_REMOTE_RESUME (PM_EVENT_REMOTE | PM_EVENT_RESUME) 386 #define PM_EVENT_AUTO_SUSPEND (PM_EVENT_AUTO | PM_EVENT_SUSPEND) 387 #define PM_EVENT_AUTO_RESUME (PM_EVENT_AUTO | PM_EVENT_RESUME) 388 389 #define PMSG_INVALID ((struct pm_message){ .event = PM_EVENT_INVALID, }) 390 #define PMSG_ON ((struct pm_message){ .event = PM_EVENT_ON, }) 391 #define PMSG_FREEZE ((struct pm_message){ .event = PM_EVENT_FREEZE, }) 392 #define PMSG_QUIESCE ((struct pm_message){ .event = PM_EVENT_QUIESCE, }) 393 #define PMSG_SUSPEND ((struct pm_message){ .event = PM_EVENT_SUSPEND, }) 394 #define PMSG_HIBERNATE ((struct pm_message){ .event = PM_EVENT_HIBERNATE, }) 395 #define PMSG_RESUME ((struct pm_message){ .event = PM_EVENT_RESUME, }) 396 #define PMSG_THAW ((struct pm_message){ .event = PM_EVENT_THAW, }) 397 #define PMSG_RESTORE ((struct pm_message){ .event = PM_EVENT_RESTORE, }) 398 #define PMSG_RECOVER ((struct pm_message){ .event = PM_EVENT_RECOVER, }) 399 #define PMSG_USER_SUSPEND ((struct pm_message) \ 400 { .event = PM_EVENT_USER_SUSPEND, }) 401 #define PMSG_USER_RESUME ((struct pm_message) \ 402 { .event = PM_EVENT_USER_RESUME, }) 403 #define PMSG_REMOTE_RESUME ((struct pm_message) \ 404 { .event = PM_EVENT_REMOTE_RESUME, }) 405 #define PMSG_AUTO_SUSPEND ((struct pm_message) \ 406 { .event = PM_EVENT_AUTO_SUSPEND, }) 407 #define PMSG_AUTO_RESUME ((struct pm_message) \ 408 { .event = PM_EVENT_AUTO_RESUME, }) 409 410 #define PMSG_IS_AUTO(msg) (((msg).event & PM_EVENT_AUTO) != 0) 411 412 /** 413 * Device run-time power management status. 414 * 415 * These status labels are used internally by the PM core to indicate the 416 * current status of a device with respect to the PM core operations. They do 417 * not reflect the actual power state of the device or its status as seen by the 418 * driver. 419 * 420 * RPM_ACTIVE Device is fully operational. Indicates that the device 421 * bus type's ->runtime_resume() callback has completed 422 * successfully. 423 * 424 * RPM_SUSPENDED Device bus type's ->runtime_suspend() callback has 425 * completed successfully. The device is regarded as 426 * suspended. 427 * 428 * RPM_RESUMING Device bus type's ->runtime_resume() callback is being 429 * executed. 430 * 431 * RPM_SUSPENDING Device bus type's ->runtime_suspend() callback is being 432 * executed. 433 */ 434 435 enum rpm_status { 436 RPM_ACTIVE = 0, 437 RPM_RESUMING, 438 RPM_SUSPENDED, 439 RPM_SUSPENDING, 440 }; 441 442 /** 443 * Device run-time power management request types. 444 * 445 * RPM_REQ_NONE Do nothing. 446 * 447 * RPM_REQ_IDLE Run the device bus type's ->runtime_idle() callback 448 * 449 * RPM_REQ_SUSPEND Run the device bus type's ->runtime_suspend() callback 450 * 451 * RPM_REQ_AUTOSUSPEND Same as RPM_REQ_SUSPEND, but not until the device has 452 * been inactive for as long as power.autosuspend_delay 453 * 454 * RPM_REQ_RESUME Run the device bus type's ->runtime_resume() callback 455 */ 456 457 enum rpm_request { 458 RPM_REQ_NONE = 0, 459 RPM_REQ_IDLE, 460 RPM_REQ_SUSPEND, 461 RPM_REQ_AUTOSUSPEND, 462 RPM_REQ_RESUME, 463 }; 464 465 struct wakeup_source; 466 467 struct pm_domain_data { 468 struct list_head list_node; 469 struct device *dev; 470 }; 471 472 struct pm_subsys_data { 473 spinlock_t lock; 474 unsigned int refcount; 475 #ifdef CONFIG_PM_CLK 476 struct list_head clock_list; 477 #endif 478 #ifdef CONFIG_PM_GENERIC_DOMAINS 479 struct pm_domain_data *domain_data; 480 #endif 481 }; 482 483 struct dev_pm_info { 484 pm_message_t power_state; 485 unsigned int can_wakeup:1; 486 unsigned int async_suspend:1; 487 bool is_prepared:1; /* Owned by the PM core */ 488 bool is_suspended:1; /* Ditto */ 489 bool ignore_children:1; 490 spinlock_t lock; 491 #ifdef CONFIG_PM_SLEEP 492 struct list_head entry; 493 struct completion completion; 494 struct wakeup_source *wakeup; 495 bool wakeup_path:1; 496 #else 497 unsigned int should_wakeup:1; 498 #endif 499 #ifdef CONFIG_PM_RUNTIME 500 struct timer_list suspend_timer; 501 unsigned long timer_expires; 502 struct work_struct work; 503 wait_queue_head_t wait_queue; 504 atomic_t usage_count; 505 atomic_t child_count; 506 unsigned int disable_depth:3; 507 unsigned int idle_notification:1; 508 unsigned int request_pending:1; 509 unsigned int deferred_resume:1; 510 unsigned int run_wake:1; 511 unsigned int runtime_auto:1; 512 unsigned int no_callbacks:1; 513 unsigned int irq_safe:1; 514 unsigned int use_autosuspend:1; 515 unsigned int timer_autosuspends:1; 516 enum rpm_request request; 517 enum rpm_status runtime_status; 518 int runtime_error; 519 int autosuspend_delay; 520 unsigned long last_busy; 521 unsigned long active_jiffies; 522 unsigned long suspended_jiffies; 523 unsigned long accounting_timestamp; 524 #endif 525 struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */ 526 struct pm_qos_constraints *constraints; 527 }; 528 529 extern void update_pm_runtime_accounting(struct device *dev); 530 extern int dev_pm_get_subsys_data(struct device *dev); 531 extern int dev_pm_put_subsys_data(struct device *dev); 532 533 /* 534 * Power domains provide callbacks that are executed during system suspend, 535 * hibernation, system resume and during runtime PM transitions along with 536 * subsystem-level and driver-level callbacks. 537 */ 538 struct dev_pm_domain { 539 struct dev_pm_ops ops; 540 }; 541 542 /* 543 * The PM_EVENT_ messages are also used by drivers implementing the legacy 544 * suspend framework, based on the ->suspend() and ->resume() callbacks common 545 * for suspend and hibernation transitions, according to the rules below. 546 */ 547 548 /* Necessary, because several drivers use PM_EVENT_PRETHAW */ 549 #define PM_EVENT_PRETHAW PM_EVENT_QUIESCE 550 551 /* 552 * One transition is triggered by resume(), after a suspend() call; the 553 * message is implicit: 554 * 555 * ON Driver starts working again, responding to hardware events 556 * and software requests. The hardware may have gone through 557 * a power-off reset, or it may have maintained state from the 558 * previous suspend() which the driver will rely on while 559 * resuming. On most platforms, there are no restrictions on 560 * availability of resources like clocks during resume(). 561 * 562 * Other transitions are triggered by messages sent using suspend(). All 563 * these transitions quiesce the driver, so that I/O queues are inactive. 564 * That commonly entails turning off IRQs and DMA; there may be rules 565 * about how to quiesce that are specific to the bus or the device's type. 566 * (For example, network drivers mark the link state.) Other details may 567 * differ according to the message: 568 * 569 * SUSPEND Quiesce, enter a low power device state appropriate for 570 * the upcoming system state (such as PCI_D3hot), and enable 571 * wakeup events as appropriate. 572 * 573 * HIBERNATE Enter a low power device state appropriate for the hibernation 574 * state (eg. ACPI S4) and enable wakeup events as appropriate. 575 * 576 * FREEZE Quiesce operations so that a consistent image can be saved; 577 * but do NOT otherwise enter a low power device state, and do 578 * NOT emit system wakeup events. 579 * 580 * PRETHAW Quiesce as if for FREEZE; additionally, prepare for restoring 581 * the system from a snapshot taken after an earlier FREEZE. 582 * Some drivers will need to reset their hardware state instead 583 * of preserving it, to ensure that it's never mistaken for the 584 * state which that earlier snapshot had set up. 585 * 586 * A minimally power-aware driver treats all messages as SUSPEND, fully 587 * reinitializes its device during resume() -- whether or not it was reset 588 * during the suspend/resume cycle -- and can't issue wakeup events. 589 * 590 * More power-aware drivers may also use low power states at runtime as 591 * well as during system sleep states like PM_SUSPEND_STANDBY. They may 592 * be able to use wakeup events to exit from runtime low-power states, 593 * or from system low-power states such as standby or suspend-to-RAM. 594 */ 595 596 #ifdef CONFIG_PM_SLEEP 597 extern void device_pm_lock(void); 598 extern void dpm_resume_noirq(pm_message_t state); 599 extern void dpm_resume_end(pm_message_t state); 600 extern void dpm_resume(pm_message_t state); 601 extern void dpm_complete(pm_message_t state); 602 603 extern void device_pm_unlock(void); 604 extern int dpm_suspend_noirq(pm_message_t state); 605 extern int dpm_suspend_start(pm_message_t state); 606 extern int dpm_suspend(pm_message_t state); 607 extern int dpm_prepare(pm_message_t state); 608 609 extern void __suspend_report_result(const char *function, void *fn, int ret); 610 611 #define suspend_report_result(fn, ret) \ 612 do { \ 613 __suspend_report_result(__func__, fn, ret); \ 614 } while (0) 615 616 extern int device_pm_wait_for_dev(struct device *sub, struct device *dev); 617 618 extern int pm_generic_prepare(struct device *dev); 619 extern int pm_generic_suspend_noirq(struct device *dev); 620 extern int pm_generic_suspend(struct device *dev); 621 extern int pm_generic_resume_noirq(struct device *dev); 622 extern int pm_generic_resume(struct device *dev); 623 extern int pm_generic_freeze_noirq(struct device *dev); 624 extern int pm_generic_freeze(struct device *dev); 625 extern int pm_generic_thaw_noirq(struct device *dev); 626 extern int pm_generic_thaw(struct device *dev); 627 extern int pm_generic_restore_noirq(struct device *dev); 628 extern int pm_generic_restore(struct device *dev); 629 extern int pm_generic_poweroff_noirq(struct device *dev); 630 extern int pm_generic_poweroff(struct device *dev); 631 extern void pm_generic_complete(struct device *dev); 632 633 #else /* !CONFIG_PM_SLEEP */ 634 635 #define device_pm_lock() do {} while (0) 636 #define device_pm_unlock() do {} while (0) 637 638 static inline int dpm_suspend_start(pm_message_t state) 639 { 640 return 0; 641 } 642 643 #define suspend_report_result(fn, ret) do {} while (0) 644 645 static inline int device_pm_wait_for_dev(struct device *a, struct device *b) 646 { 647 return 0; 648 } 649 650 #define pm_generic_prepare NULL 651 #define pm_generic_suspend NULL 652 #define pm_generic_resume NULL 653 #define pm_generic_freeze NULL 654 #define pm_generic_thaw NULL 655 #define pm_generic_restore NULL 656 #define pm_generic_poweroff NULL 657 #define pm_generic_complete NULL 658 #endif /* !CONFIG_PM_SLEEP */ 659 660 /* How to reorder dpm_list after device_move() */ 661 enum dpm_order { 662 DPM_ORDER_NONE, 663 DPM_ORDER_DEV_AFTER_PARENT, 664 DPM_ORDER_PARENT_BEFORE_DEV, 665 DPM_ORDER_DEV_LAST, 666 }; 667 668 #endif /* _LINUX_PM_H */ 669