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1/*
2 * drivers/base/dd.c - The core device/driver interactions.
3 *
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
7 *
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
11 *
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
14 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
15 * Copyright (c) 2007-2009 Novell Inc.
16 *
17 * This file is released under the GPLv2
18 */
19
20#include <linux/device.h>
21#include <linux/delay.h>
22#include <linux/module.h>
23#include <linux/kthread.h>
24#include <linux/wait.h>
25#include <linux/async.h>
26#include <linux/pm_runtime.h>
27#include <linux/pinctrl/devinfo.h>
28
29#include "base.h"
30#include "power/power.h"
31
32/*
33 * Deferred Probe infrastructure.
34 *
35 * Sometimes driver probe order matters, but the kernel doesn't always have
36 * dependency information which means some drivers will get probed before a
37 * resource it depends on is available. For example, an SDHCI driver may
38 * first need a GPIO line from an i2c GPIO controller before it can be
39 * initialized. If a required resource is not available yet, a driver can
40 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
41 *
42 * Deferred probe maintains two lists of devices, a pending list and an active
43 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
44 * pending list. A successful driver probe will trigger moving all devices
45 * from the pending to the active list so that the workqueue will eventually
46 * retry them.
47 *
48 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
49 * of the (struct device*)->p->deferred_probe pointers are manipulated
50 */
51static DEFINE_MUTEX(deferred_probe_mutex);
52static LIST_HEAD(deferred_probe_pending_list);
53static LIST_HEAD(deferred_probe_active_list);
54static struct workqueue_struct *deferred_wq;
55static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
56
57/**
58 * deferred_probe_work_func() - Retry probing devices in the active list.
59 */
60static void deferred_probe_work_func(struct work_struct *work)
61{
62 struct device *dev;
63 struct device_private *private;
64 /*
65 * This block processes every device in the deferred 'active' list.
66 * Each device is removed from the active list and passed to
67 * bus_probe_device() to re-attempt the probe. The loop continues
68 * until every device in the active list is removed and retried.
69 *
70 * Note: Once the device is removed from the list and the mutex is
71 * released, it is possible for the device get freed by another thread
72 * and cause a illegal pointer dereference. This code uses
73 * get/put_device() to ensure the device structure cannot disappear
74 * from under our feet.
75 */
76 mutex_lock(&deferred_probe_mutex);
77 while (!list_empty(&deferred_probe_active_list)) {
78 private = list_first_entry(&deferred_probe_active_list,
79 typeof(*dev->p), deferred_probe);
80 dev = private->device;
81 list_del_init(&private->deferred_probe);
82
83 get_device(dev);
84
85 /*
86 * Drop the mutex while probing each device; the probe path may
87 * manipulate the deferred list
88 */
89 mutex_unlock(&deferred_probe_mutex);
90
91 /*
92 * Force the device to the end of the dpm_list since
93 * the PM code assumes that the order we add things to
94 * the list is a good order for suspend but deferred
95 * probe makes that very unsafe.
96 */
97 device_pm_lock();
98 device_pm_move_last(dev);
99 device_pm_unlock();
100
101 dev_dbg(dev, "Retrying from deferred list\n");
102 bus_probe_device(dev);
103
104 mutex_lock(&deferred_probe_mutex);
105
106 put_device(dev);
107 }
108 mutex_unlock(&deferred_probe_mutex);
109}
110static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
111
112static void driver_deferred_probe_add(struct device *dev)
113{
114 mutex_lock(&deferred_probe_mutex);
115 if (list_empty(&dev->p->deferred_probe)) {
116 dev_dbg(dev, "Added to deferred list\n");
117 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
118 }
119 mutex_unlock(&deferred_probe_mutex);
120}
121
122void driver_deferred_probe_del(struct device *dev)
123{
124 mutex_lock(&deferred_probe_mutex);
125 if (!list_empty(&dev->p->deferred_probe)) {
126 dev_dbg(dev, "Removed from deferred list\n");
127 list_del_init(&dev->p->deferred_probe);
128 }
129 mutex_unlock(&deferred_probe_mutex);
130}
131
132static bool driver_deferred_probe_enable = false;
133/**
134 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
135 *
136 * This functions moves all devices from the pending list to the active
137 * list and schedules the deferred probe workqueue to process them. It
138 * should be called anytime a driver is successfully bound to a device.
139 *
140 * Note, there is a race condition in multi-threaded probe. In the case where
141 * more than one device is probing at the same time, it is possible for one
142 * probe to complete successfully while another is about to defer. If the second
143 * depends on the first, then it will get put on the pending list after the
144 * trigger event has already occured and will be stuck there.
145 *
146 * The atomic 'deferred_trigger_count' is used to determine if a successful
147 * trigger has occurred in the midst of probing a driver. If the trigger count
148 * changes in the midst of a probe, then deferred processing should be triggered
149 * again.
150 */
151static void driver_deferred_probe_trigger(void)
152{
153 if (!driver_deferred_probe_enable)
154 return;
155
156 /*
157 * A successful probe means that all the devices in the pending list
158 * should be triggered to be reprobed. Move all the deferred devices
159 * into the active list so they can be retried by the workqueue
160 */
161 mutex_lock(&deferred_probe_mutex);
162 atomic_inc(&deferred_trigger_count);
163 list_splice_tail_init(&deferred_probe_pending_list,
164 &deferred_probe_active_list);
165 mutex_unlock(&deferred_probe_mutex);
166
167 /*
168 * Kick the re-probe thread. It may already be scheduled, but it is
169 * safe to kick it again.
170 */
171 queue_work(deferred_wq, &deferred_probe_work);
172}
173
174/**
175 * deferred_probe_initcall() - Enable probing of deferred devices
176 *
177 * We don't want to get in the way when the bulk of drivers are getting probed.
178 * Instead, this initcall makes sure that deferred probing is delayed until
179 * late_initcall time.
180 */
181static int deferred_probe_initcall(void)
182{
183 deferred_wq = create_singlethread_workqueue("deferwq");
184 if (WARN_ON(!deferred_wq))
185 return -ENOMEM;
186
187 driver_deferred_probe_enable = true;
188 driver_deferred_probe_trigger();
189 /* Sort as many dependencies as possible before exiting initcalls */
190 flush_workqueue(deferred_wq);
191 return 0;
192}
193late_initcall(deferred_probe_initcall);
194
195static void driver_bound(struct device *dev)
196{
197 if (klist_node_attached(&dev->p->knode_driver)) {
198 printk(KERN_WARNING "%s: device %s already bound\n",
199 __func__, kobject_name(&dev->kobj));
200 return;
201 }
202
203 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
204 __func__, dev_name(dev));
205
206 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
207
208 /*
209 * Make sure the device is no longer in one of the deferred lists and
210 * kick off retrying all pending devices
211 */
212 driver_deferred_probe_del(dev);
213 driver_deferred_probe_trigger();
214
215 if (dev->bus)
216 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
217 BUS_NOTIFY_BOUND_DRIVER, dev);
218}
219
220static int driver_sysfs_add(struct device *dev)
221{
222 int ret;
223
224 if (dev->bus)
225 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
226 BUS_NOTIFY_BIND_DRIVER, dev);
227
228 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
229 kobject_name(&dev->kobj));
230 if (ret == 0) {
231 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
232 "driver");
233 if (ret)
234 sysfs_remove_link(&dev->driver->p->kobj,
235 kobject_name(&dev->kobj));
236 }
237 return ret;
238}
239
240static void driver_sysfs_remove(struct device *dev)
241{
242 struct device_driver *drv = dev->driver;
243
244 if (drv) {
245 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
246 sysfs_remove_link(&dev->kobj, "driver");
247 }
248}
249
250/**
251 * device_bind_driver - bind a driver to one device.
252 * @dev: device.
253 *
254 * Allow manual attachment of a driver to a device.
255 * Caller must have already set @dev->driver.
256 *
257 * Note that this does not modify the bus reference count
258 * nor take the bus's rwsem. Please verify those are accounted
259 * for before calling this. (It is ok to call with no other effort
260 * from a driver's probe() method.)
261 *
262 * This function must be called with the device lock held.
263 */
264int device_bind_driver(struct device *dev)
265{
266 int ret;
267
268 ret = driver_sysfs_add(dev);
269 if (!ret)
270 driver_bound(dev);
271 return ret;
272}
273EXPORT_SYMBOL_GPL(device_bind_driver);
274
275static atomic_t probe_count = ATOMIC_INIT(0);
276static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
277
278static int really_probe(struct device *dev, struct device_driver *drv)
279{
280 int ret = 0;
281 int local_trigger_count = atomic_read(&deferred_trigger_count);
282
283 atomic_inc(&probe_count);
284 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
285 drv->bus->name, __func__, drv->name, dev_name(dev));
286 WARN_ON(!list_empty(&dev->devres_head));
287
288 dev->driver = drv;
289
290 /* If using pinctrl, bind pins now before probing */
291 ret = pinctrl_bind_pins(dev);
292 if (ret)
293 goto probe_failed;
294
295 if (driver_sysfs_add(dev)) {
296 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
297 __func__, dev_name(dev));
298 goto probe_failed;
299 }
300
301 if (dev->bus->probe) {
302 ret = dev->bus->probe(dev);
303 if (ret)
304 goto probe_failed;
305 } else if (drv->probe) {
306 ret = drv->probe(dev);
307 if (ret)
308 goto probe_failed;
309 }
310
311 driver_bound(dev);
312 ret = 1;
313 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
314 drv->bus->name, __func__, dev_name(dev), drv->name);
315 goto done;
316
317probe_failed:
318 devres_release_all(dev);
319 driver_sysfs_remove(dev);
320 dev->driver = NULL;
321 dev_set_drvdata(dev, NULL);
322
323 if (ret == -EPROBE_DEFER) {
324 /* Driver requested deferred probing */
325 dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
326 driver_deferred_probe_add(dev);
327 /* Did a trigger occur while probing? Need to re-trigger if yes */
328 if (local_trigger_count != atomic_read(&deferred_trigger_count))
329 driver_deferred_probe_trigger();
330 } else if (ret != -ENODEV && ret != -ENXIO) {
331 /* driver matched but the probe failed */
332 printk(KERN_WARNING
333 "%s: probe of %s failed with error %d\n",
334 drv->name, dev_name(dev), ret);
335 } else {
336 pr_debug("%s: probe of %s rejects match %d\n",
337 drv->name, dev_name(dev), ret);
338 }
339 /*
340 * Ignore errors returned by ->probe so that the next driver can try
341 * its luck.
342 */
343 ret = 0;
344done:
345 atomic_dec(&probe_count);
346 wake_up(&probe_waitqueue);
347 return ret;
348}
349
350/**
351 * driver_probe_done
352 * Determine if the probe sequence is finished or not.
353 *
354 * Should somehow figure out how to use a semaphore, not an atomic variable...
355 */
356int driver_probe_done(void)
357{
358 pr_debug("%s: probe_count = %d\n", __func__,
359 atomic_read(&probe_count));
360 if (atomic_read(&probe_count))
361 return -EBUSY;
362 return 0;
363}
364
365/**
366 * wait_for_device_probe
367 * Wait for device probing to be completed.
368 */
369void wait_for_device_probe(void)
370{
371 /* wait for the known devices to complete their probing */
372 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
373 async_synchronize_full();
374}
375EXPORT_SYMBOL_GPL(wait_for_device_probe);
376
377/**
378 * driver_probe_device - attempt to bind device & driver together
379 * @drv: driver to bind a device to
380 * @dev: device to try to bind to the driver
381 *
382 * This function returns -ENODEV if the device is not registered,
383 * 1 if the device is bound successfully and 0 otherwise.
384 *
385 * This function must be called with @dev lock held. When called for a
386 * USB interface, @dev->parent lock must be held as well.
387 */
388int driver_probe_device(struct device_driver *drv, struct device *dev)
389{
390 int ret = 0;
391
392 if (!device_is_registered(dev))
393 return -ENODEV;
394
395 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
396 drv->bus->name, __func__, dev_name(dev), drv->name);
397
398 pm_runtime_barrier(dev);
399 ret = really_probe(dev, drv);
400 pm_request_idle(dev);
401
402 return ret;
403}
404
405static int __device_attach(struct device_driver *drv, void *data)
406{
407 struct device *dev = data;
408
409 if (!driver_match_device(drv, dev))
410 return 0;
411
412 return driver_probe_device(drv, dev);
413}
414
415/**
416 * device_attach - try to attach device to a driver.
417 * @dev: device.
418 *
419 * Walk the list of drivers that the bus has and call
420 * driver_probe_device() for each pair. If a compatible
421 * pair is found, break out and return.
422 *
423 * Returns 1 if the device was bound to a driver;
424 * 0 if no matching driver was found;
425 * -ENODEV if the device is not registered.
426 *
427 * When called for a USB interface, @dev->parent lock must be held.
428 */
429int device_attach(struct device *dev)
430{
431 int ret = 0;
432
433 device_lock(dev);
434 if (dev->driver) {
435 if (klist_node_attached(&dev->p->knode_driver)) {
436 ret = 1;
437 goto out_unlock;
438 }
439 ret = device_bind_driver(dev);
440 if (ret == 0)
441 ret = 1;
442 else {
443 dev->driver = NULL;
444 ret = 0;
445 }
446 } else {
447 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
448 pm_request_idle(dev);
449 }
450out_unlock:
451 device_unlock(dev);
452 return ret;
453}
454EXPORT_SYMBOL_GPL(device_attach);
455
456static int __driver_attach(struct device *dev, void *data)
457{
458 struct device_driver *drv = data;
459
460 /*
461 * Lock device and try to bind to it. We drop the error
462 * here and always return 0, because we need to keep trying
463 * to bind to devices and some drivers will return an error
464 * simply if it didn't support the device.
465 *
466 * driver_probe_device() will spit a warning if there
467 * is an error.
468 */
469
470 if (!driver_match_device(drv, dev))
471 return 0;
472
473 if (dev->parent) /* Needed for USB */
474 device_lock(dev->parent);
475 device_lock(dev);
476 if (!dev->driver)
477 driver_probe_device(drv, dev);
478 device_unlock(dev);
479 if (dev->parent)
480 device_unlock(dev->parent);
481
482 return 0;
483}
484
485/**
486 * driver_attach - try to bind driver to devices.
487 * @drv: driver.
488 *
489 * Walk the list of devices that the bus has on it and try to
490 * match the driver with each one. If driver_probe_device()
491 * returns 0 and the @dev->driver is set, we've found a
492 * compatible pair.
493 */
494int driver_attach(struct device_driver *drv)
495{
496 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
497}
498EXPORT_SYMBOL_GPL(driver_attach);
499
500/*
501 * __device_release_driver() must be called with @dev lock held.
502 * When called for a USB interface, @dev->parent lock must be held as well.
503 */
504static void __device_release_driver(struct device *dev)
505{
506 struct device_driver *drv;
507
508 drv = dev->driver;
509 if (drv) {
510 pm_runtime_get_sync(dev);
511
512 driver_sysfs_remove(dev);
513
514 if (dev->bus)
515 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
516 BUS_NOTIFY_UNBIND_DRIVER,
517 dev);
518
519 pm_runtime_put_sync(dev);
520
521 if (dev->bus && dev->bus->remove)
522 dev->bus->remove(dev);
523 else if (drv->remove)
524 drv->remove(dev);
525 devres_release_all(dev);
526 dev->driver = NULL;
527 dev_set_drvdata(dev, NULL);
528 klist_remove(&dev->p->knode_driver);
529 if (dev->bus)
530 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
531 BUS_NOTIFY_UNBOUND_DRIVER,
532 dev);
533
534 }
535}
536
537/**
538 * device_release_driver - manually detach device from driver.
539 * @dev: device.
540 *
541 * Manually detach device from driver.
542 * When called for a USB interface, @dev->parent lock must be held.
543 */
544void device_release_driver(struct device *dev)
545{
546 /*
547 * If anyone calls device_release_driver() recursively from
548 * within their ->remove callback for the same device, they
549 * will deadlock right here.
550 */
551 device_lock(dev);
552 __device_release_driver(dev);
553 device_unlock(dev);
554}
555EXPORT_SYMBOL_GPL(device_release_driver);
556
557/**
558 * driver_detach - detach driver from all devices it controls.
559 * @drv: driver.
560 */
561void driver_detach(struct device_driver *drv)
562{
563 struct device_private *dev_prv;
564 struct device *dev;
565
566 for (;;) {
567 spin_lock(&drv->p->klist_devices.k_lock);
568 if (list_empty(&drv->p->klist_devices.k_list)) {
569 spin_unlock(&drv->p->klist_devices.k_lock);
570 break;
571 }
572 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
573 struct device_private,
574 knode_driver.n_node);
575 dev = dev_prv->device;
576 get_device(dev);
577 spin_unlock(&drv->p->klist_devices.k_lock);
578
579 if (dev->parent) /* Needed for USB */
580 device_lock(dev->parent);
581 device_lock(dev);
582 if (dev->driver == drv)
583 __device_release_driver(dev);
584 device_unlock(dev);
585 if (dev->parent)
586 device_unlock(dev->parent);
587 put_device(dev);
588 }
589}
590
591/*
592 * These exports can't be _GPL due to .h files using this within them, and it
593 * might break something that was previously working...
594 */
595void *dev_get_drvdata(const struct device *dev)
596{
597 if (dev && dev->p)
598 return dev->p->driver_data;
599 return NULL;
600}
601EXPORT_SYMBOL(dev_get_drvdata);
602
603int dev_set_drvdata(struct device *dev, void *data)
604{
605 int error;
606
607 if (!dev->p) {
608 error = device_private_init(dev);
609 if (error)
610 return error;
611 }
612 dev->p->driver_data = data;
613 return 0;
614}
615EXPORT_SYMBOL(dev_set_drvdata);
1/*
2 * drivers/base/dd.c - The core device/driver interactions.
3 *
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
7 *
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
11 *
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
14 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
15 * Copyright (c) 2007-2009 Novell Inc.
16 *
17 * This file is released under the GPLv2
18 */
19
20#include <linux/device.h>
21#include <linux/delay.h>
22#include <linux/module.h>
23#include <linux/kthread.h>
24#include <linux/wait.h>
25#include <linux/async.h>
26#include <linux/pm_runtime.h>
27#include <scsi/scsi_scan.h>
28
29#include "base.h"
30#include "power/power.h"
31
32/*
33 * Deferred Probe infrastructure.
34 *
35 * Sometimes driver probe order matters, but the kernel doesn't always have
36 * dependency information which means some drivers will get probed before a
37 * resource it depends on is available. For example, an SDHCI driver may
38 * first need a GPIO line from an i2c GPIO controller before it can be
39 * initialized. If a required resource is not available yet, a driver can
40 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
41 *
42 * Deferred probe maintains two lists of devices, a pending list and an active
43 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
44 * pending list. A successful driver probe will trigger moving all devices
45 * from the pending to the active list so that the workqueue will eventually
46 * retry them.
47 *
48 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
49 * of the (struct device*)->p->deferred_probe pointers are manipulated
50 */
51static DEFINE_MUTEX(deferred_probe_mutex);
52static LIST_HEAD(deferred_probe_pending_list);
53static LIST_HEAD(deferred_probe_active_list);
54static struct workqueue_struct *deferred_wq;
55
56/**
57 * deferred_probe_work_func() - Retry probing devices in the active list.
58 */
59static void deferred_probe_work_func(struct work_struct *work)
60{
61 struct device *dev;
62 struct device_private *private;
63 /*
64 * This block processes every device in the deferred 'active' list.
65 * Each device is removed from the active list and passed to
66 * bus_probe_device() to re-attempt the probe. The loop continues
67 * until every device in the active list is removed and retried.
68 *
69 * Note: Once the device is removed from the list and the mutex is
70 * released, it is possible for the device get freed by another thread
71 * and cause a illegal pointer dereference. This code uses
72 * get/put_device() to ensure the device structure cannot disappear
73 * from under our feet.
74 */
75 mutex_lock(&deferred_probe_mutex);
76 while (!list_empty(&deferred_probe_active_list)) {
77 private = list_first_entry(&deferred_probe_active_list,
78 typeof(*dev->p), deferred_probe);
79 dev = private->device;
80 list_del_init(&private->deferred_probe);
81
82 get_device(dev);
83
84 /*
85 * Drop the mutex while probing each device; the probe path may
86 * manipulate the deferred list
87 */
88 mutex_unlock(&deferred_probe_mutex);
89 dev_dbg(dev, "Retrying from deferred list\n");
90 bus_probe_device(dev);
91 mutex_lock(&deferred_probe_mutex);
92
93 put_device(dev);
94 }
95 mutex_unlock(&deferred_probe_mutex);
96}
97static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
98
99static void driver_deferred_probe_add(struct device *dev)
100{
101 mutex_lock(&deferred_probe_mutex);
102 if (list_empty(&dev->p->deferred_probe)) {
103 dev_dbg(dev, "Added to deferred list\n");
104 list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
105 }
106 mutex_unlock(&deferred_probe_mutex);
107}
108
109void driver_deferred_probe_del(struct device *dev)
110{
111 mutex_lock(&deferred_probe_mutex);
112 if (!list_empty(&dev->p->deferred_probe)) {
113 dev_dbg(dev, "Removed from deferred list\n");
114 list_del_init(&dev->p->deferred_probe);
115 }
116 mutex_unlock(&deferred_probe_mutex);
117}
118
119static bool driver_deferred_probe_enable = false;
120/**
121 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
122 *
123 * This functions moves all devices from the pending list to the active
124 * list and schedules the deferred probe workqueue to process them. It
125 * should be called anytime a driver is successfully bound to a device.
126 */
127static void driver_deferred_probe_trigger(void)
128{
129 if (!driver_deferred_probe_enable)
130 return;
131
132 /*
133 * A successful probe means that all the devices in the pending list
134 * should be triggered to be reprobed. Move all the deferred devices
135 * into the active list so they can be retried by the workqueue
136 */
137 mutex_lock(&deferred_probe_mutex);
138 list_splice_tail_init(&deferred_probe_pending_list,
139 &deferred_probe_active_list);
140 mutex_unlock(&deferred_probe_mutex);
141
142 /*
143 * Kick the re-probe thread. It may already be scheduled, but it is
144 * safe to kick it again.
145 */
146 queue_work(deferred_wq, &deferred_probe_work);
147}
148
149/**
150 * deferred_probe_initcall() - Enable probing of deferred devices
151 *
152 * We don't want to get in the way when the bulk of drivers are getting probed.
153 * Instead, this initcall makes sure that deferred probing is delayed until
154 * late_initcall time.
155 */
156static int deferred_probe_initcall(void)
157{
158 deferred_wq = create_singlethread_workqueue("deferwq");
159 if (WARN_ON(!deferred_wq))
160 return -ENOMEM;
161
162 driver_deferred_probe_enable = true;
163 driver_deferred_probe_trigger();
164 return 0;
165}
166late_initcall(deferred_probe_initcall);
167
168static void driver_bound(struct device *dev)
169{
170 if (klist_node_attached(&dev->p->knode_driver)) {
171 printk(KERN_WARNING "%s: device %s already bound\n",
172 __func__, kobject_name(&dev->kobj));
173 return;
174 }
175
176 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev),
177 __func__, dev->driver->name);
178
179 klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
180
181 /*
182 * Make sure the device is no longer in one of the deferred lists and
183 * kick off retrying all pending devices
184 */
185 driver_deferred_probe_del(dev);
186 driver_deferred_probe_trigger();
187
188 if (dev->bus)
189 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
190 BUS_NOTIFY_BOUND_DRIVER, dev);
191}
192
193static int driver_sysfs_add(struct device *dev)
194{
195 int ret;
196
197 if (dev->bus)
198 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
199 BUS_NOTIFY_BIND_DRIVER, dev);
200
201 ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
202 kobject_name(&dev->kobj));
203 if (ret == 0) {
204 ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
205 "driver");
206 if (ret)
207 sysfs_remove_link(&dev->driver->p->kobj,
208 kobject_name(&dev->kobj));
209 }
210 return ret;
211}
212
213static void driver_sysfs_remove(struct device *dev)
214{
215 struct device_driver *drv = dev->driver;
216
217 if (drv) {
218 sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
219 sysfs_remove_link(&dev->kobj, "driver");
220 }
221}
222
223/**
224 * device_bind_driver - bind a driver to one device.
225 * @dev: device.
226 *
227 * Allow manual attachment of a driver to a device.
228 * Caller must have already set @dev->driver.
229 *
230 * Note that this does not modify the bus reference count
231 * nor take the bus's rwsem. Please verify those are accounted
232 * for before calling this. (It is ok to call with no other effort
233 * from a driver's probe() method.)
234 *
235 * This function must be called with the device lock held.
236 */
237int device_bind_driver(struct device *dev)
238{
239 int ret;
240
241 ret = driver_sysfs_add(dev);
242 if (!ret)
243 driver_bound(dev);
244 return ret;
245}
246EXPORT_SYMBOL_GPL(device_bind_driver);
247
248static atomic_t probe_count = ATOMIC_INIT(0);
249static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
250
251static int really_probe(struct device *dev, struct device_driver *drv)
252{
253 int ret = 0;
254
255 atomic_inc(&probe_count);
256 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
257 drv->bus->name, __func__, drv->name, dev_name(dev));
258 WARN_ON(!list_empty(&dev->devres_head));
259
260 dev->driver = drv;
261 if (driver_sysfs_add(dev)) {
262 printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
263 __func__, dev_name(dev));
264 goto probe_failed;
265 }
266
267 if (dev->bus->probe) {
268 ret = dev->bus->probe(dev);
269 if (ret)
270 goto probe_failed;
271 } else if (drv->probe) {
272 ret = drv->probe(dev);
273 if (ret)
274 goto probe_failed;
275 }
276
277 driver_bound(dev);
278 ret = 1;
279 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
280 drv->bus->name, __func__, dev_name(dev), drv->name);
281 goto done;
282
283probe_failed:
284 devres_release_all(dev);
285 driver_sysfs_remove(dev);
286 dev->driver = NULL;
287
288 if (ret == -EPROBE_DEFER) {
289 /* Driver requested deferred probing */
290 dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
291 driver_deferred_probe_add(dev);
292 } else if (ret != -ENODEV && ret != -ENXIO) {
293 /* driver matched but the probe failed */
294 printk(KERN_WARNING
295 "%s: probe of %s failed with error %d\n",
296 drv->name, dev_name(dev), ret);
297 } else {
298 pr_debug("%s: probe of %s rejects match %d\n",
299 drv->name, dev_name(dev), ret);
300 }
301 /*
302 * Ignore errors returned by ->probe so that the next driver can try
303 * its luck.
304 */
305 ret = 0;
306done:
307 atomic_dec(&probe_count);
308 wake_up(&probe_waitqueue);
309 return ret;
310}
311
312/**
313 * driver_probe_done
314 * Determine if the probe sequence is finished or not.
315 *
316 * Should somehow figure out how to use a semaphore, not an atomic variable...
317 */
318int driver_probe_done(void)
319{
320 pr_debug("%s: probe_count = %d\n", __func__,
321 atomic_read(&probe_count));
322 if (atomic_read(&probe_count))
323 return -EBUSY;
324 return 0;
325}
326
327/**
328 * wait_for_device_probe
329 * Wait for device probing to be completed.
330 */
331void wait_for_device_probe(void)
332{
333 /* wait for the known devices to complete their probing */
334 wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
335 async_synchronize_full();
336 scsi_complete_async_scans();
337}
338EXPORT_SYMBOL_GPL(wait_for_device_probe);
339
340/**
341 * driver_probe_device - attempt to bind device & driver together
342 * @drv: driver to bind a device to
343 * @dev: device to try to bind to the driver
344 *
345 * This function returns -ENODEV if the device is not registered,
346 * 1 if the device is bound successfully and 0 otherwise.
347 *
348 * This function must be called with @dev lock held. When called for a
349 * USB interface, @dev->parent lock must be held as well.
350 */
351int driver_probe_device(struct device_driver *drv, struct device *dev)
352{
353 int ret = 0;
354
355 if (!device_is_registered(dev))
356 return -ENODEV;
357
358 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
359 drv->bus->name, __func__, dev_name(dev), drv->name);
360
361 pm_runtime_get_noresume(dev);
362 pm_runtime_barrier(dev);
363 ret = really_probe(dev, drv);
364 pm_runtime_put_sync(dev);
365
366 return ret;
367}
368
369static int __device_attach(struct device_driver *drv, void *data)
370{
371 struct device *dev = data;
372
373 if (!driver_match_device(drv, dev))
374 return 0;
375
376 return driver_probe_device(drv, dev);
377}
378
379/**
380 * device_attach - try to attach device to a driver.
381 * @dev: device.
382 *
383 * Walk the list of drivers that the bus has and call
384 * driver_probe_device() for each pair. If a compatible
385 * pair is found, break out and return.
386 *
387 * Returns 1 if the device was bound to a driver;
388 * 0 if no matching driver was found;
389 * -ENODEV if the device is not registered.
390 *
391 * When called for a USB interface, @dev->parent lock must be held.
392 */
393int device_attach(struct device *dev)
394{
395 int ret = 0;
396
397 device_lock(dev);
398 if (dev->driver) {
399 if (klist_node_attached(&dev->p->knode_driver)) {
400 ret = 1;
401 goto out_unlock;
402 }
403 ret = device_bind_driver(dev);
404 if (ret == 0)
405 ret = 1;
406 else {
407 dev->driver = NULL;
408 ret = 0;
409 }
410 } else {
411 pm_runtime_get_noresume(dev);
412 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
413 pm_runtime_put_sync(dev);
414 }
415out_unlock:
416 device_unlock(dev);
417 return ret;
418}
419EXPORT_SYMBOL_GPL(device_attach);
420
421static int __driver_attach(struct device *dev, void *data)
422{
423 struct device_driver *drv = data;
424
425 /*
426 * Lock device and try to bind to it. We drop the error
427 * here and always return 0, because we need to keep trying
428 * to bind to devices and some drivers will return an error
429 * simply if it didn't support the device.
430 *
431 * driver_probe_device() will spit a warning if there
432 * is an error.
433 */
434
435 if (!driver_match_device(drv, dev))
436 return 0;
437
438 if (dev->parent) /* Needed for USB */
439 device_lock(dev->parent);
440 device_lock(dev);
441 if (!dev->driver)
442 driver_probe_device(drv, dev);
443 device_unlock(dev);
444 if (dev->parent)
445 device_unlock(dev->parent);
446
447 return 0;
448}
449
450/**
451 * driver_attach - try to bind driver to devices.
452 * @drv: driver.
453 *
454 * Walk the list of devices that the bus has on it and try to
455 * match the driver with each one. If driver_probe_device()
456 * returns 0 and the @dev->driver is set, we've found a
457 * compatible pair.
458 */
459int driver_attach(struct device_driver *drv)
460{
461 return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
462}
463EXPORT_SYMBOL_GPL(driver_attach);
464
465/*
466 * __device_release_driver() must be called with @dev lock held.
467 * When called for a USB interface, @dev->parent lock must be held as well.
468 */
469static void __device_release_driver(struct device *dev)
470{
471 struct device_driver *drv;
472
473 drv = dev->driver;
474 if (drv) {
475 pm_runtime_get_sync(dev);
476
477 driver_sysfs_remove(dev);
478
479 if (dev->bus)
480 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
481 BUS_NOTIFY_UNBIND_DRIVER,
482 dev);
483
484 pm_runtime_put_sync(dev);
485
486 if (dev->bus && dev->bus->remove)
487 dev->bus->remove(dev);
488 else if (drv->remove)
489 drv->remove(dev);
490 devres_release_all(dev);
491 dev->driver = NULL;
492 klist_remove(&dev->p->knode_driver);
493 if (dev->bus)
494 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
495 BUS_NOTIFY_UNBOUND_DRIVER,
496 dev);
497
498 }
499}
500
501/**
502 * device_release_driver - manually detach device from driver.
503 * @dev: device.
504 *
505 * Manually detach device from driver.
506 * When called for a USB interface, @dev->parent lock must be held.
507 */
508void device_release_driver(struct device *dev)
509{
510 /*
511 * If anyone calls device_release_driver() recursively from
512 * within their ->remove callback for the same device, they
513 * will deadlock right here.
514 */
515 device_lock(dev);
516 __device_release_driver(dev);
517 device_unlock(dev);
518}
519EXPORT_SYMBOL_GPL(device_release_driver);
520
521/**
522 * driver_detach - detach driver from all devices it controls.
523 * @drv: driver.
524 */
525void driver_detach(struct device_driver *drv)
526{
527 struct device_private *dev_prv;
528 struct device *dev;
529
530 for (;;) {
531 spin_lock(&drv->p->klist_devices.k_lock);
532 if (list_empty(&drv->p->klist_devices.k_list)) {
533 spin_unlock(&drv->p->klist_devices.k_lock);
534 break;
535 }
536 dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
537 struct device_private,
538 knode_driver.n_node);
539 dev = dev_prv->device;
540 get_device(dev);
541 spin_unlock(&drv->p->klist_devices.k_lock);
542
543 if (dev->parent) /* Needed for USB */
544 device_lock(dev->parent);
545 device_lock(dev);
546 if (dev->driver == drv)
547 __device_release_driver(dev);
548 device_unlock(dev);
549 if (dev->parent)
550 device_unlock(dev->parent);
551 put_device(dev);
552 }
553}
554
555/*
556 * These exports can't be _GPL due to .h files using this within them, and it
557 * might break something that was previously working...
558 */
559void *dev_get_drvdata(const struct device *dev)
560{
561 if (dev && dev->p)
562 return dev->p->driver_data;
563 return NULL;
564}
565EXPORT_SYMBOL(dev_get_drvdata);
566
567int dev_set_drvdata(struct device *dev, void *data)
568{
569 int error;
570
571 if (!dev->p) {
572 error = device_private_init(dev);
573 if (error)
574 return error;
575 }
576 dev->p->driver_data = data;
577 return 0;
578}
579EXPORT_SYMBOL(dev_set_drvdata);