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