main.c 21 KB

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  1. /*
  2. * drivers/base/power/main.c - Where the driver meets power management.
  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. *
  10. * The driver model core calls device_pm_add() when a device is registered.
  11. * This will intialize the embedded device_pm_info object in the device
  12. * and add it to the list of power-controlled devices. sysfs entries for
  13. * controlling device power management will also be added.
  14. *
  15. * A separate list is used for keeping track of power info, because the power
  16. * domain dependencies may differ from the ancestral dependencies that the
  17. * subsystem list maintains.
  18. */
  19. #include <linux/device.h>
  20. #include <linux/kallsyms.h>
  21. #include <linux/mutex.h>
  22. #include <linux/pm.h>
  23. #include <linux/pm_runtime.h>
  24. #include <linux/resume-trace.h>
  25. #include <linux/rwsem.h>
  26. #include <linux/interrupt.h>
  27. #include <linux/sched.h>
  28. #include "../base.h"
  29. #include "power.h"
  30. /*
  31. * The entries in the dpm_list list are in a depth first order, simply
  32. * because children are guaranteed to be discovered after parents, and
  33. * are inserted at the back of the list on discovery.
  34. *
  35. * Since device_pm_add() may be called with a device semaphore held,
  36. * we must never try to acquire a device semaphore while holding
  37. * dpm_list_mutex.
  38. */
  39. LIST_HEAD(dpm_list);
  40. static DEFINE_MUTEX(dpm_list_mtx);
  41. /*
  42. * Set once the preparation of devices for a PM transition has started, reset
  43. * before starting to resume devices. Protected by dpm_list_mtx.
  44. */
  45. static bool transition_started;
  46. /**
  47. * device_pm_init - Initialize the PM-related part of a device object.
  48. * @dev: Device object being initialized.
  49. */
  50. void device_pm_init(struct device *dev)
  51. {
  52. dev->power.status = DPM_ON;
  53. pm_runtime_init(dev);
  54. }
  55. /**
  56. * device_pm_lock - Lock the list of active devices used by the PM core.
  57. */
  58. void device_pm_lock(void)
  59. {
  60. mutex_lock(&dpm_list_mtx);
  61. }
  62. /**
  63. * device_pm_unlock - Unlock the list of active devices used by the PM core.
  64. */
  65. void device_pm_unlock(void)
  66. {
  67. mutex_unlock(&dpm_list_mtx);
  68. }
  69. /**
  70. * device_pm_add - Add a device to the PM core's list of active devices.
  71. * @dev: Device to add to the list.
  72. */
  73. void device_pm_add(struct device *dev)
  74. {
  75. pr_debug("PM: Adding info for %s:%s\n",
  76. dev->bus ? dev->bus->name : "No Bus",
  77. kobject_name(&dev->kobj));
  78. mutex_lock(&dpm_list_mtx);
  79. if (dev->parent) {
  80. if (dev->parent->power.status >= DPM_SUSPENDING)
  81. dev_warn(dev, "parent %s should not be sleeping\n",
  82. dev_name(dev->parent));
  83. } else if (transition_started) {
  84. /*
  85. * We refuse to register parentless devices while a PM
  86. * transition is in progress in order to avoid leaving them
  87. * unhandled down the road
  88. */
  89. dev_WARN(dev, "Parentless device registered during a PM transaction\n");
  90. }
  91. list_add_tail(&dev->power.entry, &dpm_list);
  92. mutex_unlock(&dpm_list_mtx);
  93. }
  94. /**
  95. * device_pm_remove - Remove a device from the PM core's list of active devices.
  96. * @dev: Device to be removed from the list.
  97. */
  98. void device_pm_remove(struct device *dev)
  99. {
  100. pr_debug("PM: Removing info for %s:%s\n",
  101. dev->bus ? dev->bus->name : "No Bus",
  102. kobject_name(&dev->kobj));
  103. mutex_lock(&dpm_list_mtx);
  104. list_del_init(&dev->power.entry);
  105. mutex_unlock(&dpm_list_mtx);
  106. pm_runtime_remove(dev);
  107. }
  108. /**
  109. * device_pm_move_before - Move device in the PM core's list of active devices.
  110. * @deva: Device to move in dpm_list.
  111. * @devb: Device @deva should come before.
  112. */
  113. void device_pm_move_before(struct device *deva, struct device *devb)
  114. {
  115. pr_debug("PM: Moving %s:%s before %s:%s\n",
  116. deva->bus ? deva->bus->name : "No Bus",
  117. kobject_name(&deva->kobj),
  118. devb->bus ? devb->bus->name : "No Bus",
  119. kobject_name(&devb->kobj));
  120. /* Delete deva from dpm_list and reinsert before devb. */
  121. list_move_tail(&deva->power.entry, &devb->power.entry);
  122. }
  123. /**
  124. * device_pm_move_after - Move device in the PM core's list of active devices.
  125. * @deva: Device to move in dpm_list.
  126. * @devb: Device @deva should come after.
  127. */
  128. void device_pm_move_after(struct device *deva, struct device *devb)
  129. {
  130. pr_debug("PM: Moving %s:%s after %s:%s\n",
  131. deva->bus ? deva->bus->name : "No Bus",
  132. kobject_name(&deva->kobj),
  133. devb->bus ? devb->bus->name : "No Bus",
  134. kobject_name(&devb->kobj));
  135. /* Delete deva from dpm_list and reinsert after devb. */
  136. list_move(&deva->power.entry, &devb->power.entry);
  137. }
  138. /**
  139. * device_pm_move_last - Move device to end of the PM core's list of devices.
  140. * @dev: Device to move in dpm_list.
  141. */
  142. void device_pm_move_last(struct device *dev)
  143. {
  144. pr_debug("PM: Moving %s:%s to end of list\n",
  145. dev->bus ? dev->bus->name : "No Bus",
  146. kobject_name(&dev->kobj));
  147. list_move_tail(&dev->power.entry, &dpm_list);
  148. }
  149. /**
  150. * pm_op - Execute the PM operation appropriate for given PM event.
  151. * @dev: Device to handle.
  152. * @ops: PM operations to choose from.
  153. * @state: PM transition of the system being carried out.
  154. */
  155. static int pm_op(struct device *dev,
  156. const struct dev_pm_ops *ops,
  157. pm_message_t state)
  158. {
  159. int error = 0;
  160. ktime_t calltime, delta, rettime;
  161. if (initcall_debug) {
  162. pr_info("calling %s+ @ %i\n",
  163. dev_name(dev), task_pid_nr(current));
  164. calltime = ktime_get();
  165. }
  166. switch (state.event) {
  167. #ifdef CONFIG_SUSPEND
  168. case PM_EVENT_SUSPEND:
  169. if (ops->suspend) {
  170. error = ops->suspend(dev);
  171. suspend_report_result(ops->suspend, error);
  172. }
  173. break;
  174. case PM_EVENT_RESUME:
  175. if (ops->resume) {
  176. error = ops->resume(dev);
  177. suspend_report_result(ops->resume, error);
  178. }
  179. break;
  180. #endif /* CONFIG_SUSPEND */
  181. #ifdef CONFIG_HIBERNATION
  182. case PM_EVENT_FREEZE:
  183. case PM_EVENT_QUIESCE:
  184. if (ops->freeze) {
  185. error = ops->freeze(dev);
  186. suspend_report_result(ops->freeze, error);
  187. }
  188. break;
  189. case PM_EVENT_HIBERNATE:
  190. if (ops->poweroff) {
  191. error = ops->poweroff(dev);
  192. suspend_report_result(ops->poweroff, error);
  193. }
  194. break;
  195. case PM_EVENT_THAW:
  196. case PM_EVENT_RECOVER:
  197. if (ops->thaw) {
  198. error = ops->thaw(dev);
  199. suspend_report_result(ops->thaw, error);
  200. }
  201. break;
  202. case PM_EVENT_RESTORE:
  203. if (ops->restore) {
  204. error = ops->restore(dev);
  205. suspend_report_result(ops->restore, error);
  206. }
  207. break;
  208. #endif /* CONFIG_HIBERNATION */
  209. default:
  210. error = -EINVAL;
  211. }
  212. if (initcall_debug) {
  213. rettime = ktime_get();
  214. delta = ktime_sub(rettime, calltime);
  215. pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
  216. error, (unsigned long long)ktime_to_ns(delta) >> 10);
  217. }
  218. return error;
  219. }
  220. /**
  221. * pm_noirq_op - Execute the PM operation appropriate for given PM event.
  222. * @dev: Device to handle.
  223. * @ops: PM operations to choose from.
  224. * @state: PM transition of the system being carried out.
  225. *
  226. * The driver of @dev will not receive interrupts while this function is being
  227. * executed.
  228. */
  229. static int pm_noirq_op(struct device *dev,
  230. const struct dev_pm_ops *ops,
  231. pm_message_t state)
  232. {
  233. int error = 0;
  234. ktime_t calltime, delta, rettime;
  235. if (initcall_debug) {
  236. pr_info("calling %s_i+ @ %i\n",
  237. dev_name(dev), task_pid_nr(current));
  238. calltime = ktime_get();
  239. }
  240. switch (state.event) {
  241. #ifdef CONFIG_SUSPEND
  242. case PM_EVENT_SUSPEND:
  243. if (ops->suspend_noirq) {
  244. error = ops->suspend_noirq(dev);
  245. suspend_report_result(ops->suspend_noirq, error);
  246. }
  247. break;
  248. case PM_EVENT_RESUME:
  249. if (ops->resume_noirq) {
  250. error = ops->resume_noirq(dev);
  251. suspend_report_result(ops->resume_noirq, error);
  252. }
  253. break;
  254. #endif /* CONFIG_SUSPEND */
  255. #ifdef CONFIG_HIBERNATION
  256. case PM_EVENT_FREEZE:
  257. case PM_EVENT_QUIESCE:
  258. if (ops->freeze_noirq) {
  259. error = ops->freeze_noirq(dev);
  260. suspend_report_result(ops->freeze_noirq, error);
  261. }
  262. break;
  263. case PM_EVENT_HIBERNATE:
  264. if (ops->poweroff_noirq) {
  265. error = ops->poweroff_noirq(dev);
  266. suspend_report_result(ops->poweroff_noirq, error);
  267. }
  268. break;
  269. case PM_EVENT_THAW:
  270. case PM_EVENT_RECOVER:
  271. if (ops->thaw_noirq) {
  272. error = ops->thaw_noirq(dev);
  273. suspend_report_result(ops->thaw_noirq, error);
  274. }
  275. break;
  276. case PM_EVENT_RESTORE:
  277. if (ops->restore_noirq) {
  278. error = ops->restore_noirq(dev);
  279. suspend_report_result(ops->restore_noirq, error);
  280. }
  281. break;
  282. #endif /* CONFIG_HIBERNATION */
  283. default:
  284. error = -EINVAL;
  285. }
  286. if (initcall_debug) {
  287. rettime = ktime_get();
  288. delta = ktime_sub(rettime, calltime);
  289. printk("initcall %s_i+ returned %d after %Ld usecs\n", dev_name(dev),
  290. error, (unsigned long long)ktime_to_ns(delta) >> 10);
  291. }
  292. return error;
  293. }
  294. static char *pm_verb(int event)
  295. {
  296. switch (event) {
  297. case PM_EVENT_SUSPEND:
  298. return "suspend";
  299. case PM_EVENT_RESUME:
  300. return "resume";
  301. case PM_EVENT_FREEZE:
  302. return "freeze";
  303. case PM_EVENT_QUIESCE:
  304. return "quiesce";
  305. case PM_EVENT_HIBERNATE:
  306. return "hibernate";
  307. case PM_EVENT_THAW:
  308. return "thaw";
  309. case PM_EVENT_RESTORE:
  310. return "restore";
  311. case PM_EVENT_RECOVER:
  312. return "recover";
  313. default:
  314. return "(unknown PM event)";
  315. }
  316. }
  317. static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
  318. {
  319. dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
  320. ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
  321. ", may wakeup" : "");
  322. }
  323. static void pm_dev_err(struct device *dev, pm_message_t state, char *info,
  324. int error)
  325. {
  326. printk(KERN_ERR "PM: Device %s failed to %s%s: error %d\n",
  327. kobject_name(&dev->kobj), pm_verb(state.event), info, error);
  328. }
  329. /*------------------------- Resume routines -------------------------*/
  330. /**
  331. * device_resume_noirq - Execute an "early resume" callback for given device.
  332. * @dev: Device to handle.
  333. * @state: PM transition of the system being carried out.
  334. *
  335. * The driver of @dev will not receive interrupts while this function is being
  336. * executed.
  337. */
  338. static int device_resume_noirq(struct device *dev, pm_message_t state)
  339. {
  340. int error = 0;
  341. TRACE_DEVICE(dev);
  342. TRACE_RESUME(0);
  343. if (dev->bus && dev->bus->pm) {
  344. pm_dev_dbg(dev, state, "EARLY ");
  345. error = pm_noirq_op(dev, dev->bus->pm, state);
  346. }
  347. TRACE_RESUME(error);
  348. return error;
  349. }
  350. /**
  351. * dpm_resume_noirq - Execute "early resume" callbacks for non-sysdev devices.
  352. * @state: PM transition of the system being carried out.
  353. *
  354. * Call the "noirq" resume handlers for all devices marked as DPM_OFF_IRQ and
  355. * enable device drivers to receive interrupts.
  356. */
  357. void dpm_resume_noirq(pm_message_t state)
  358. {
  359. struct device *dev;
  360. mutex_lock(&dpm_list_mtx);
  361. transition_started = false;
  362. list_for_each_entry(dev, &dpm_list, power.entry)
  363. if (dev->power.status > DPM_OFF) {
  364. int error;
  365. dev->power.status = DPM_OFF;
  366. error = device_resume_noirq(dev, state);
  367. if (error)
  368. pm_dev_err(dev, state, " early", error);
  369. }
  370. mutex_unlock(&dpm_list_mtx);
  371. resume_device_irqs();
  372. }
  373. EXPORT_SYMBOL_GPL(dpm_resume_noirq);
  374. /**
  375. * device_resume - Execute "resume" callbacks for given device.
  376. * @dev: Device to handle.
  377. * @state: PM transition of the system being carried out.
  378. */
  379. static int device_resume(struct device *dev, pm_message_t state)
  380. {
  381. int error = 0;
  382. TRACE_DEVICE(dev);
  383. TRACE_RESUME(0);
  384. down(&dev->sem);
  385. if (dev->bus) {
  386. if (dev->bus->pm) {
  387. pm_dev_dbg(dev, state, "");
  388. error = pm_op(dev, dev->bus->pm, state);
  389. } else if (dev->bus->resume) {
  390. pm_dev_dbg(dev, state, "legacy ");
  391. error = dev->bus->resume(dev);
  392. }
  393. if (error)
  394. goto End;
  395. }
  396. if (dev->type) {
  397. if (dev->type->pm) {
  398. pm_dev_dbg(dev, state, "type ");
  399. error = pm_op(dev, dev->type->pm, state);
  400. }
  401. if (error)
  402. goto End;
  403. }
  404. if (dev->class) {
  405. if (dev->class->pm) {
  406. pm_dev_dbg(dev, state, "class ");
  407. error = pm_op(dev, dev->class->pm, state);
  408. } else if (dev->class->resume) {
  409. pm_dev_dbg(dev, state, "legacy class ");
  410. error = dev->class->resume(dev);
  411. }
  412. }
  413. End:
  414. up(&dev->sem);
  415. TRACE_RESUME(error);
  416. return error;
  417. }
  418. /**
  419. * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
  420. * @state: PM transition of the system being carried out.
  421. *
  422. * Execute the appropriate "resume" callback for all devices whose status
  423. * indicates that they are suspended.
  424. */
  425. static void dpm_resume(pm_message_t state)
  426. {
  427. struct list_head list;
  428. INIT_LIST_HEAD(&list);
  429. mutex_lock(&dpm_list_mtx);
  430. while (!list_empty(&dpm_list)) {
  431. struct device *dev = to_device(dpm_list.next);
  432. get_device(dev);
  433. if (dev->power.status >= DPM_OFF) {
  434. int error;
  435. dev->power.status = DPM_RESUMING;
  436. mutex_unlock(&dpm_list_mtx);
  437. error = device_resume(dev, state);
  438. mutex_lock(&dpm_list_mtx);
  439. if (error)
  440. pm_dev_err(dev, state, "", error);
  441. } else if (dev->power.status == DPM_SUSPENDING) {
  442. /* Allow new children of the device to be registered */
  443. dev->power.status = DPM_RESUMING;
  444. }
  445. if (!list_empty(&dev->power.entry))
  446. list_move_tail(&dev->power.entry, &list);
  447. put_device(dev);
  448. }
  449. list_splice(&list, &dpm_list);
  450. mutex_unlock(&dpm_list_mtx);
  451. }
  452. /**
  453. * device_complete - Complete a PM transition for given device.
  454. * @dev: Device to handle.
  455. * @state: PM transition of the system being carried out.
  456. */
  457. static void device_complete(struct device *dev, pm_message_t state)
  458. {
  459. down(&dev->sem);
  460. if (dev->class && dev->class->pm && dev->class->pm->complete) {
  461. pm_dev_dbg(dev, state, "completing class ");
  462. dev->class->pm->complete(dev);
  463. }
  464. if (dev->type && dev->type->pm && dev->type->pm->complete) {
  465. pm_dev_dbg(dev, state, "completing type ");
  466. dev->type->pm->complete(dev);
  467. }
  468. if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {
  469. pm_dev_dbg(dev, state, "completing ");
  470. dev->bus->pm->complete(dev);
  471. }
  472. up(&dev->sem);
  473. }
  474. /**
  475. * dpm_complete - Complete a PM transition for all non-sysdev devices.
  476. * @state: PM transition of the system being carried out.
  477. *
  478. * Execute the ->complete() callbacks for all devices whose PM status is not
  479. * DPM_ON (this allows new devices to be registered).
  480. */
  481. static void dpm_complete(pm_message_t state)
  482. {
  483. struct list_head list;
  484. INIT_LIST_HEAD(&list);
  485. mutex_lock(&dpm_list_mtx);
  486. transition_started = false;
  487. while (!list_empty(&dpm_list)) {
  488. struct device *dev = to_device(dpm_list.prev);
  489. get_device(dev);
  490. if (dev->power.status > DPM_ON) {
  491. dev->power.status = DPM_ON;
  492. mutex_unlock(&dpm_list_mtx);
  493. device_complete(dev, state);
  494. pm_runtime_put_noidle(dev);
  495. mutex_lock(&dpm_list_mtx);
  496. }
  497. if (!list_empty(&dev->power.entry))
  498. list_move(&dev->power.entry, &list);
  499. put_device(dev);
  500. }
  501. list_splice(&list, &dpm_list);
  502. mutex_unlock(&dpm_list_mtx);
  503. }
  504. /**
  505. * dpm_resume_end - Execute "resume" callbacks and complete system transition.
  506. * @state: PM transition of the system being carried out.
  507. *
  508. * Execute "resume" callbacks for all devices and complete the PM transition of
  509. * the system.
  510. */
  511. void dpm_resume_end(pm_message_t state)
  512. {
  513. might_sleep();
  514. dpm_resume(state);
  515. dpm_complete(state);
  516. }
  517. EXPORT_SYMBOL_GPL(dpm_resume_end);
  518. /*------------------------- Suspend routines -------------------------*/
  519. /**
  520. * resume_event - Return a "resume" message for given "suspend" sleep state.
  521. * @sleep_state: PM message representing a sleep state.
  522. *
  523. * Return a PM message representing the resume event corresponding to given
  524. * sleep state.
  525. */
  526. static pm_message_t resume_event(pm_message_t sleep_state)
  527. {
  528. switch (sleep_state.event) {
  529. case PM_EVENT_SUSPEND:
  530. return PMSG_RESUME;
  531. case PM_EVENT_FREEZE:
  532. case PM_EVENT_QUIESCE:
  533. return PMSG_RECOVER;
  534. case PM_EVENT_HIBERNATE:
  535. return PMSG_RESTORE;
  536. }
  537. return PMSG_ON;
  538. }
  539. /**
  540. * device_suspend_noirq - Execute a "late suspend" callback for given device.
  541. * @dev: Device to handle.
  542. * @state: PM transition of the system being carried out.
  543. *
  544. * The driver of @dev will not receive interrupts while this function is being
  545. * executed.
  546. */
  547. static int device_suspend_noirq(struct device *dev, pm_message_t state)
  548. {
  549. int error = 0;
  550. if (dev->bus && dev->bus->pm) {
  551. pm_dev_dbg(dev, state, "LATE ");
  552. error = pm_noirq_op(dev, dev->bus->pm, state);
  553. }
  554. return error;
  555. }
  556. /**
  557. * dpm_suspend_noirq - Execute "late suspend" callbacks for non-sysdev devices.
  558. * @state: PM transition of the system being carried out.
  559. *
  560. * Prevent device drivers from receiving interrupts and call the "noirq" suspend
  561. * handlers for all non-sysdev devices.
  562. */
  563. int dpm_suspend_noirq(pm_message_t state)
  564. {
  565. struct device *dev;
  566. int error = 0;
  567. suspend_device_irqs();
  568. mutex_lock(&dpm_list_mtx);
  569. list_for_each_entry_reverse(dev, &dpm_list, power.entry) {
  570. error = device_suspend_noirq(dev, state);
  571. if (error) {
  572. pm_dev_err(dev, state, " late", error);
  573. break;
  574. }
  575. dev->power.status = DPM_OFF_IRQ;
  576. }
  577. mutex_unlock(&dpm_list_mtx);
  578. if (error)
  579. dpm_resume_noirq(resume_event(state));
  580. return error;
  581. }
  582. EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
  583. /**
  584. * device_suspend - Execute "suspend" callbacks for given device.
  585. * @dev: Device to handle.
  586. * @state: PM transition of the system being carried out.
  587. */
  588. static int device_suspend(struct device *dev, pm_message_t state)
  589. {
  590. int error = 0;
  591. down(&dev->sem);
  592. if (dev->class) {
  593. if (dev->class->pm) {
  594. pm_dev_dbg(dev, state, "class ");
  595. error = pm_op(dev, dev->class->pm, state);
  596. } else if (dev->class->suspend) {
  597. pm_dev_dbg(dev, state, "legacy class ");
  598. error = dev->class->suspend(dev, state);
  599. suspend_report_result(dev->class->suspend, error);
  600. }
  601. if (error)
  602. goto End;
  603. }
  604. if (dev->type) {
  605. if (dev->type->pm) {
  606. pm_dev_dbg(dev, state, "type ");
  607. error = pm_op(dev, dev->type->pm, state);
  608. }
  609. if (error)
  610. goto End;
  611. }
  612. if (dev->bus) {
  613. if (dev->bus->pm) {
  614. pm_dev_dbg(dev, state, "");
  615. error = pm_op(dev, dev->bus->pm, state);
  616. } else if (dev->bus->suspend) {
  617. pm_dev_dbg(dev, state, "legacy ");
  618. error = dev->bus->suspend(dev, state);
  619. suspend_report_result(dev->bus->suspend, error);
  620. }
  621. }
  622. End:
  623. up(&dev->sem);
  624. return error;
  625. }
  626. /**
  627. * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
  628. * @state: PM transition of the system being carried out.
  629. */
  630. static int dpm_suspend(pm_message_t state)
  631. {
  632. struct list_head list;
  633. int error = 0;
  634. INIT_LIST_HEAD(&list);
  635. mutex_lock(&dpm_list_mtx);
  636. while (!list_empty(&dpm_list)) {
  637. struct device *dev = to_device(dpm_list.prev);
  638. get_device(dev);
  639. mutex_unlock(&dpm_list_mtx);
  640. error = device_suspend(dev, state);
  641. mutex_lock(&dpm_list_mtx);
  642. if (error) {
  643. pm_dev_err(dev, state, "", error);
  644. put_device(dev);
  645. break;
  646. }
  647. dev->power.status = DPM_OFF;
  648. if (!list_empty(&dev->power.entry))
  649. list_move(&dev->power.entry, &list);
  650. put_device(dev);
  651. }
  652. list_splice(&list, dpm_list.prev);
  653. mutex_unlock(&dpm_list_mtx);
  654. return error;
  655. }
  656. /**
  657. * device_prepare - Prepare a device for system power transition.
  658. * @dev: Device to handle.
  659. * @state: PM transition of the system being carried out.
  660. *
  661. * Execute the ->prepare() callback(s) for given device. No new children of the
  662. * device may be registered after this function has returned.
  663. */
  664. static int device_prepare(struct device *dev, pm_message_t state)
  665. {
  666. int error = 0;
  667. down(&dev->sem);
  668. if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {
  669. pm_dev_dbg(dev, state, "preparing ");
  670. error = dev->bus->pm->prepare(dev);
  671. suspend_report_result(dev->bus->pm->prepare, error);
  672. if (error)
  673. goto End;
  674. }
  675. if (dev->type && dev->type->pm && dev->type->pm->prepare) {
  676. pm_dev_dbg(dev, state, "preparing type ");
  677. error = dev->type->pm->prepare(dev);
  678. suspend_report_result(dev->type->pm->prepare, error);
  679. if (error)
  680. goto End;
  681. }
  682. if (dev->class && dev->class->pm && dev->class->pm->prepare) {
  683. pm_dev_dbg(dev, state, "preparing class ");
  684. error = dev->class->pm->prepare(dev);
  685. suspend_report_result(dev->class->pm->prepare, error);
  686. }
  687. End:
  688. up(&dev->sem);
  689. return error;
  690. }
  691. /**
  692. * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
  693. * @state: PM transition of the system being carried out.
  694. *
  695. * Execute the ->prepare() callback(s) for all devices.
  696. */
  697. static int dpm_prepare(pm_message_t state)
  698. {
  699. struct list_head list;
  700. int error = 0;
  701. INIT_LIST_HEAD(&list);
  702. mutex_lock(&dpm_list_mtx);
  703. transition_started = true;
  704. while (!list_empty(&dpm_list)) {
  705. struct device *dev = to_device(dpm_list.next);
  706. get_device(dev);
  707. dev->power.status = DPM_PREPARING;
  708. mutex_unlock(&dpm_list_mtx);
  709. pm_runtime_get_noresume(dev);
  710. if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) {
  711. /* Wake-up requested during system sleep transition. */
  712. pm_runtime_put_noidle(dev);
  713. error = -EBUSY;
  714. } else {
  715. error = device_prepare(dev, state);
  716. }
  717. mutex_lock(&dpm_list_mtx);
  718. if (error) {
  719. dev->power.status = DPM_ON;
  720. if (error == -EAGAIN) {
  721. put_device(dev);
  722. error = 0;
  723. continue;
  724. }
  725. printk(KERN_ERR "PM: Failed to prepare device %s "
  726. "for power transition: error %d\n",
  727. kobject_name(&dev->kobj), error);
  728. put_device(dev);
  729. break;
  730. }
  731. dev->power.status = DPM_SUSPENDING;
  732. if (!list_empty(&dev->power.entry))
  733. list_move_tail(&dev->power.entry, &list);
  734. put_device(dev);
  735. }
  736. list_splice(&list, &dpm_list);
  737. mutex_unlock(&dpm_list_mtx);
  738. return error;
  739. }
  740. /**
  741. * dpm_suspend_start - Prepare devices for PM transition and suspend them.
  742. * @state: PM transition of the system being carried out.
  743. *
  744. * Prepare all non-sysdev devices for system PM transition and execute "suspend"
  745. * callbacks for them.
  746. */
  747. int dpm_suspend_start(pm_message_t state)
  748. {
  749. int error;
  750. might_sleep();
  751. error = dpm_prepare(state);
  752. if (!error)
  753. error = dpm_suspend(state);
  754. return error;
  755. }
  756. EXPORT_SYMBOL_GPL(dpm_suspend_start);
  757. void __suspend_report_result(const char *function, void *fn, int ret)
  758. {
  759. if (ret)
  760. printk(KERN_ERR "%s(): %pF returns %d\n", function, fn, ret);
  761. }
  762. EXPORT_SYMBOL_GPL(__suspend_report_result);