Commit | Line | Data |
---|---|---|
07e4a3e2 | 1 | /* |
4a3ad20c | 2 | * drivers/base/dd.c - The core device/driver interactions. |
07e4a3e2 | 3 | * |
4a3ad20c GKH |
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. | |
07e4a3e2 | 7 | * |
4a3ad20c GKH |
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'. | |
07e4a3e2 | 11 | * |
4a3ad20c GKH |
12 | * Copyright (c) 2002-5 Patrick Mochel |
13 | * Copyright (c) 2002-3 Open Source Development Labs | |
b4028437 GKH |
14 | * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de> |
15 | * Copyright (c) 2007-2009 Novell Inc. | |
07e4a3e2 | 16 | * |
4a3ad20c | 17 | * This file is released under the GPLv2 |
07e4a3e2 | 18 | */ |
19 | ||
20 | #include <linux/device.h> | |
216773a7 | 21 | #include <linux/delay.h> |
07e4a3e2 | 22 | #include <linux/module.h> |
d779249e | 23 | #include <linux/kthread.h> |
735a7ffb | 24 | #include <linux/wait.h> |
216773a7 | 25 | #include <linux/async.h> |
5e928f77 | 26 | #include <linux/pm_runtime.h> |
ab78029e | 27 | #include <linux/pinctrl/devinfo.h> |
07e4a3e2 | 28 | |
29 | #include "base.h" | |
30 | #include "power/power.h" | |
31 | ||
d1c3414c GL |
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 | |
ef8a3fd6 | 49 | * of the (struct device*)->p->deferred_probe pointers are manipulated |
d1c3414c GL |
50 | */ |
51 | static DEFINE_MUTEX(deferred_probe_mutex); | |
52 | static LIST_HEAD(deferred_probe_pending_list); | |
53 | static LIST_HEAD(deferred_probe_active_list); | |
58b116bc | 54 | static atomic_t deferred_trigger_count = ATOMIC_INIT(0); |
d1c3414c | 55 | |
013c074f SG |
56 | /* |
57 | * In some cases, like suspend to RAM or hibernation, It might be reasonable | |
58 | * to prohibit probing of devices as it could be unsafe. | |
59 | * Once defer_all_probes is true all drivers probes will be forcibly deferred. | |
60 | */ | |
61 | static bool defer_all_probes; | |
62 | ||
41575335 | 63 | /* |
d1c3414c GL |
64 | * deferred_probe_work_func() - Retry probing devices in the active list. |
65 | */ | |
66 | static void deferred_probe_work_func(struct work_struct *work) | |
67 | { | |
68 | struct device *dev; | |
ef8a3fd6 | 69 | struct device_private *private; |
d1c3414c GL |
70 | /* |
71 | * This block processes every device in the deferred 'active' list. | |
72 | * Each device is removed from the active list and passed to | |
73 | * bus_probe_device() to re-attempt the probe. The loop continues | |
74 | * until every device in the active list is removed and retried. | |
75 | * | |
76 | * Note: Once the device is removed from the list and the mutex is | |
77 | * released, it is possible for the device get freed by another thread | |
78 | * and cause a illegal pointer dereference. This code uses | |
79 | * get/put_device() to ensure the device structure cannot disappear | |
80 | * from under our feet. | |
81 | */ | |
82 | mutex_lock(&deferred_probe_mutex); | |
83 | while (!list_empty(&deferred_probe_active_list)) { | |
ef8a3fd6 GKH |
84 | private = list_first_entry(&deferred_probe_active_list, |
85 | typeof(*dev->p), deferred_probe); | |
86 | dev = private->device; | |
87 | list_del_init(&private->deferred_probe); | |
d1c3414c GL |
88 | |
89 | get_device(dev); | |
90 | ||
8b0372a2 GKH |
91 | /* |
92 | * Drop the mutex while probing each device; the probe path may | |
93 | * manipulate the deferred list | |
94 | */ | |
d1c3414c | 95 | mutex_unlock(&deferred_probe_mutex); |
8153584e MB |
96 | |
97 | /* | |
98 | * Force the device to the end of the dpm_list since | |
99 | * the PM code assumes that the order we add things to | |
100 | * the list is a good order for suspend but deferred | |
101 | * probe makes that very unsafe. | |
102 | */ | |
103 | device_pm_lock(); | |
104 | device_pm_move_last(dev); | |
105 | device_pm_unlock(); | |
106 | ||
d1c3414c GL |
107 | dev_dbg(dev, "Retrying from deferred list\n"); |
108 | bus_probe_device(dev); | |
8153584e | 109 | |
d1c3414c GL |
110 | mutex_lock(&deferred_probe_mutex); |
111 | ||
112 | put_device(dev); | |
113 | } | |
114 | mutex_unlock(&deferred_probe_mutex); | |
115 | } | |
116 | static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); | |
117 | ||
118 | static void driver_deferred_probe_add(struct device *dev) | |
119 | { | |
120 | mutex_lock(&deferred_probe_mutex); | |
ef8a3fd6 | 121 | if (list_empty(&dev->p->deferred_probe)) { |
d1c3414c | 122 | dev_dbg(dev, "Added to deferred list\n"); |
1d29cfa5 | 123 | list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list); |
d1c3414c GL |
124 | } |
125 | mutex_unlock(&deferred_probe_mutex); | |
126 | } | |
127 | ||
128 | void driver_deferred_probe_del(struct device *dev) | |
129 | { | |
130 | mutex_lock(&deferred_probe_mutex); | |
ef8a3fd6 | 131 | if (!list_empty(&dev->p->deferred_probe)) { |
d1c3414c | 132 | dev_dbg(dev, "Removed from deferred list\n"); |
ef8a3fd6 | 133 | list_del_init(&dev->p->deferred_probe); |
d1c3414c GL |
134 | } |
135 | mutex_unlock(&deferred_probe_mutex); | |
136 | } | |
137 | ||
138 | static bool driver_deferred_probe_enable = false; | |
139 | /** | |
140 | * driver_deferred_probe_trigger() - Kick off re-probing deferred devices | |
141 | * | |
142 | * This functions moves all devices from the pending list to the active | |
143 | * list and schedules the deferred probe workqueue to process them. It | |
144 | * should be called anytime a driver is successfully bound to a device. | |
58b116bc GL |
145 | * |
146 | * Note, there is a race condition in multi-threaded probe. In the case where | |
147 | * more than one device is probing at the same time, it is possible for one | |
148 | * probe to complete successfully while another is about to defer. If the second | |
149 | * depends on the first, then it will get put on the pending list after the | |
9ba8af66 | 150 | * trigger event has already occurred and will be stuck there. |
58b116bc GL |
151 | * |
152 | * The atomic 'deferred_trigger_count' is used to determine if a successful | |
153 | * trigger has occurred in the midst of probing a driver. If the trigger count | |
154 | * changes in the midst of a probe, then deferred processing should be triggered | |
155 | * again. | |
d1c3414c GL |
156 | */ |
157 | static void driver_deferred_probe_trigger(void) | |
158 | { | |
159 | if (!driver_deferred_probe_enable) | |
160 | return; | |
161 | ||
8b0372a2 GKH |
162 | /* |
163 | * A successful probe means that all the devices in the pending list | |
d1c3414c | 164 | * should be triggered to be reprobed. Move all the deferred devices |
8b0372a2 GKH |
165 | * into the active list so they can be retried by the workqueue |
166 | */ | |
d1c3414c | 167 | mutex_lock(&deferred_probe_mutex); |
58b116bc | 168 | atomic_inc(&deferred_trigger_count); |
d1c3414c GL |
169 | list_splice_tail_init(&deferred_probe_pending_list, |
170 | &deferred_probe_active_list); | |
171 | mutex_unlock(&deferred_probe_mutex); | |
172 | ||
8b0372a2 GKH |
173 | /* |
174 | * Kick the re-probe thread. It may already be scheduled, but it is | |
175 | * safe to kick it again. | |
176 | */ | |
2c507e46 | 177 | schedule_work(&deferred_probe_work); |
d1c3414c GL |
178 | } |
179 | ||
013c074f SG |
180 | /** |
181 | * device_block_probing() - Block/defere device's probes | |
182 | * | |
183 | * It will disable probing of devices and defer their probes instead. | |
184 | */ | |
185 | void device_block_probing(void) | |
186 | { | |
187 | defer_all_probes = true; | |
188 | /* sync with probes to avoid races. */ | |
189 | wait_for_device_probe(); | |
190 | } | |
191 | ||
192 | /** | |
193 | * device_unblock_probing() - Unblock/enable device's probes | |
194 | * | |
195 | * It will restore normal behavior and trigger re-probing of deferred | |
196 | * devices. | |
197 | */ | |
198 | void device_unblock_probing(void) | |
199 | { | |
200 | defer_all_probes = false; | |
201 | driver_deferred_probe_trigger(); | |
202 | } | |
203 | ||
d1c3414c GL |
204 | /** |
205 | * deferred_probe_initcall() - Enable probing of deferred devices | |
206 | * | |
207 | * We don't want to get in the way when the bulk of drivers are getting probed. | |
208 | * Instead, this initcall makes sure that deferred probing is delayed until | |
209 | * late_initcall time. | |
210 | */ | |
211 | static int deferred_probe_initcall(void) | |
212 | { | |
d1c3414c GL |
213 | driver_deferred_probe_enable = true; |
214 | driver_deferred_probe_trigger(); | |
d72cca1e | 215 | /* Sort as many dependencies as possible before exiting initcalls */ |
2c507e46 | 216 | flush_work(&deferred_probe_work); |
d1c3414c GL |
217 | return 0; |
218 | } | |
219 | late_initcall(deferred_probe_initcall); | |
07e4a3e2 | 220 | |
6b9cb427 TV |
221 | /** |
222 | * device_is_bound() - Check if device is bound to a driver | |
223 | * @dev: device to check | |
224 | * | |
225 | * Returns true if passed device has already finished probing successfully | |
226 | * against a driver. | |
227 | * | |
228 | * This function must be called with the device lock held. | |
229 | */ | |
230 | bool device_is_bound(struct device *dev) | |
231 | { | |
3ded9104 | 232 | return dev->p && klist_node_attached(&dev->p->knode_driver); |
6b9cb427 TV |
233 | } |
234 | ||
1901fb26 | 235 | static void driver_bound(struct device *dev) |
07e4a3e2 | 236 | { |
6b9cb427 | 237 | if (device_is_bound(dev)) { |
f86db396 | 238 | printk(KERN_WARNING "%s: device %s already bound\n", |
2b3a302a | 239 | __func__, kobject_name(&dev->kobj)); |
1901fb26 | 240 | return; |
f86db396 | 241 | } |
4c898c7f | 242 | |
94f8cc0e FR |
243 | pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name, |
244 | __func__, dev_name(dev)); | |
116af378 | 245 | |
fbb88fad SS |
246 | klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); |
247 | ||
aa8e54b5 TV |
248 | device_pm_check_callbacks(dev); |
249 | ||
8b0372a2 GKH |
250 | /* |
251 | * Make sure the device is no longer in one of the deferred lists and | |
252 | * kick off retrying all pending devices | |
253 | */ | |
d1c3414c GL |
254 | driver_deferred_probe_del(dev); |
255 | driver_deferred_probe_trigger(); | |
256 | ||
116af378 | 257 | if (dev->bus) |
c6f7e72a | 258 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 | 259 | BUS_NOTIFY_BOUND_DRIVER, dev); |
1901fb26 KS |
260 | } |
261 | ||
262 | static int driver_sysfs_add(struct device *dev) | |
263 | { | |
264 | int ret; | |
265 | ||
45daef0f MD |
266 | if (dev->bus) |
267 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
268 | BUS_NOTIFY_BIND_DRIVER, dev); | |
269 | ||
e5dd1278 | 270 | ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
07e4a3e2 | 271 | kobject_name(&dev->kobj)); |
f86db396 | 272 | if (ret == 0) { |
e5dd1278 | 273 | ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
f86db396 AM |
274 | "driver"); |
275 | if (ret) | |
e5dd1278 | 276 | sysfs_remove_link(&dev->driver->p->kobj, |
f86db396 AM |
277 | kobject_name(&dev->kobj)); |
278 | } | |
279 | return ret; | |
07e4a3e2 | 280 | } |
281 | ||
1901fb26 KS |
282 | static void driver_sysfs_remove(struct device *dev) |
283 | { | |
284 | struct device_driver *drv = dev->driver; | |
285 | ||
286 | if (drv) { | |
e5dd1278 | 287 | sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
1901fb26 KS |
288 | sysfs_remove_link(&dev->kobj, "driver"); |
289 | } | |
290 | } | |
291 | ||
292 | /** | |
4a3ad20c GKH |
293 | * device_bind_driver - bind a driver to one device. |
294 | * @dev: device. | |
1901fb26 | 295 | * |
4a3ad20c GKH |
296 | * Allow manual attachment of a driver to a device. |
297 | * Caller must have already set @dev->driver. | |
1901fb26 | 298 | * |
4a3ad20c GKH |
299 | * Note that this does not modify the bus reference count |
300 | * nor take the bus's rwsem. Please verify those are accounted | |
301 | * for before calling this. (It is ok to call with no other effort | |
302 | * from a driver's probe() method.) | |
1901fb26 | 303 | * |
8e9394ce | 304 | * This function must be called with the device lock held. |
1901fb26 KS |
305 | */ |
306 | int device_bind_driver(struct device *dev) | |
307 | { | |
cb986b74 CH |
308 | int ret; |
309 | ||
310 | ret = driver_sysfs_add(dev); | |
311 | if (!ret) | |
312 | driver_bound(dev); | |
14b6257a AS |
313 | else if (dev->bus) |
314 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
315 | BUS_NOTIFY_DRIVER_NOT_BOUND, dev); | |
cb986b74 | 316 | return ret; |
1901fb26 | 317 | } |
4a3ad20c | 318 | EXPORT_SYMBOL_GPL(device_bind_driver); |
1901fb26 | 319 | |
d779249e | 320 | static atomic_t probe_count = ATOMIC_INIT(0); |
735a7ffb AM |
321 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
322 | ||
21c7f30b | 323 | static int really_probe(struct device *dev, struct device_driver *drv) |
07e4a3e2 | 324 | { |
013c074f | 325 | int ret = -EPROBE_DEFER; |
58b116bc | 326 | int local_trigger_count = atomic_read(&deferred_trigger_count); |
bea5b158 | 327 | bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE); |
07e4a3e2 | 328 | |
013c074f SG |
329 | if (defer_all_probes) { |
330 | /* | |
331 | * Value of defer_all_probes can be set only by | |
332 | * device_defer_all_probes_enable() which, in turn, will call | |
333 | * wait_for_device_probe() right after that to avoid any races. | |
334 | */ | |
335 | dev_dbg(dev, "Driver %s force probe deferral\n", drv->name); | |
336 | driver_deferred_probe_add(dev); | |
337 | return ret; | |
338 | } | |
339 | ||
d779249e | 340 | atomic_inc(&probe_count); |
7dc72b28 | 341 | pr_debug("bus: '%s': %s: probing driver %s with device %s\n", |
1e0b2cf9 | 342 | drv->bus->name, __func__, drv->name, dev_name(dev)); |
9ac7849e | 343 | WARN_ON(!list_empty(&dev->devres_head)); |
07e4a3e2 | 344 | |
bea5b158 | 345 | re_probe: |
07e4a3e2 | 346 | dev->driver = drv; |
ab78029e LW |
347 | |
348 | /* If using pinctrl, bind pins now before probing */ | |
349 | ret = pinctrl_bind_pins(dev); | |
350 | if (ret) | |
14b6257a | 351 | goto pinctrl_bind_failed; |
ab78029e | 352 | |
1901fb26 KS |
353 | if (driver_sysfs_add(dev)) { |
354 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
1e0b2cf9 | 355 | __func__, dev_name(dev)); |
1901fb26 KS |
356 | goto probe_failed; |
357 | } | |
358 | ||
e90d5532 RW |
359 | if (dev->pm_domain && dev->pm_domain->activate) { |
360 | ret = dev->pm_domain->activate(dev); | |
361 | if (ret) | |
362 | goto probe_failed; | |
363 | } | |
364 | ||
52cdbdd4 GS |
365 | /* |
366 | * Ensure devices are listed in devices_kset in correct order | |
367 | * It's important to move Dev to the end of devices_kset before | |
368 | * calling .probe, because it could be recursive and parent Dev | |
369 | * should always go first | |
370 | */ | |
371 | devices_kset_move_last(dev); | |
372 | ||
594c8281 RK |
373 | if (dev->bus->probe) { |
374 | ret = dev->bus->probe(dev); | |
1901fb26 | 375 | if (ret) |
d779249e | 376 | goto probe_failed; |
594c8281 | 377 | } else if (drv->probe) { |
0d3e5a2e | 378 | ret = drv->probe(dev); |
1901fb26 | 379 | if (ret) |
d779249e | 380 | goto probe_failed; |
f86db396 | 381 | } |
1901fb26 | 382 | |
bea5b158 RH |
383 | if (test_remove) { |
384 | test_remove = false; | |
385 | ||
386 | if (dev->bus && dev->bus->remove) | |
387 | dev->bus->remove(dev); | |
388 | else if (drv->remove) | |
389 | drv->remove(dev); | |
390 | ||
391 | devres_release_all(dev); | |
392 | driver_sysfs_remove(dev); | |
393 | dev->driver = NULL; | |
394 | dev_set_drvdata(dev, NULL); | |
395 | if (dev->pm_domain && dev->pm_domain->dismiss) | |
396 | dev->pm_domain->dismiss(dev); | |
397 | pm_runtime_reinit(dev); | |
398 | ||
399 | goto re_probe; | |
400 | } | |
401 | ||
ef0eebc0 DA |
402 | pinctrl_init_done(dev); |
403 | ||
e90d5532 RW |
404 | if (dev->pm_domain && dev->pm_domain->sync) |
405 | dev->pm_domain->sync(dev); | |
406 | ||
1901fb26 | 407 | driver_bound(dev); |
0d3e5a2e | 408 | ret = 1; |
7dc72b28 | 409 | pr_debug("bus: '%s': %s: bound device %s to driver %s\n", |
1e0b2cf9 | 410 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 411 | goto done; |
0d3e5a2e | 412 | |
d779249e | 413 | probe_failed: |
14b6257a AS |
414 | if (dev->bus) |
415 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
416 | BUS_NOTIFY_DRIVER_NOT_BOUND, dev); | |
417 | pinctrl_bind_failed: | |
9ac7849e | 418 | devres_release_all(dev); |
1901fb26 KS |
419 | driver_sysfs_remove(dev); |
420 | dev->driver = NULL; | |
0998d063 | 421 | dev_set_drvdata(dev, NULL); |
e90d5532 RW |
422 | if (dev->pm_domain && dev->pm_domain->dismiss) |
423 | dev->pm_domain->dismiss(dev); | |
5de85b9d | 424 | pm_runtime_reinit(dev); |
1901fb26 | 425 | |
bb2b4075 SS |
426 | switch (ret) { |
427 | case -EPROBE_DEFER: | |
d1c3414c | 428 | /* Driver requested deferred probing */ |
13fcffbb | 429 | dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name); |
d1c3414c | 430 | driver_deferred_probe_add(dev); |
58b116bc GL |
431 | /* Did a trigger occur while probing? Need to re-trigger if yes */ |
432 | if (local_trigger_count != atomic_read(&deferred_trigger_count)) | |
433 | driver_deferred_probe_trigger(); | |
bb2b4075 SS |
434 | break; |
435 | case -ENODEV: | |
436 | case -ENXIO: | |
437 | pr_debug("%s: probe of %s rejects match %d\n", | |
438 | drv->name, dev_name(dev), ret); | |
439 | break; | |
440 | default: | |
0d3e5a2e PM |
441 | /* driver matched but the probe failed */ |
442 | printk(KERN_WARNING | |
443 | "%s: probe of %s failed with error %d\n", | |
1e0b2cf9 | 444 | drv->name, dev_name(dev), ret); |
0d3e5a2e | 445 | } |
c578abbc CH |
446 | /* |
447 | * Ignore errors returned by ->probe so that the next driver can try | |
448 | * its luck. | |
449 | */ | |
450 | ret = 0; | |
d779249e | 451 | done: |
d779249e | 452 | atomic_dec(&probe_count); |
735a7ffb | 453 | wake_up(&probe_waitqueue); |
d779249e GKH |
454 | return ret; |
455 | } | |
456 | ||
457 | /** | |
458 | * driver_probe_done | |
459 | * Determine if the probe sequence is finished or not. | |
460 | * | |
461 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
462 | */ | |
463 | int driver_probe_done(void) | |
464 | { | |
2b3a302a | 465 | pr_debug("%s: probe_count = %d\n", __func__, |
d779249e GKH |
466 | atomic_read(&probe_count)); |
467 | if (atomic_read(&probe_count)) | |
468 | return -EBUSY; | |
469 | return 0; | |
470 | } | |
471 | ||
216773a7 AV |
472 | /** |
473 | * wait_for_device_probe | |
474 | * Wait for device probing to be completed. | |
216773a7 | 475 | */ |
b23530eb | 476 | void wait_for_device_probe(void) |
216773a7 | 477 | { |
013c074f | 478 | /* wait for the deferred probe workqueue to finish */ |
2c507e46 | 479 | flush_work(&deferred_probe_work); |
013c074f | 480 | |
216773a7 | 481 | /* wait for the known devices to complete their probing */ |
b23530eb | 482 | wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); |
216773a7 | 483 | async_synchronize_full(); |
216773a7 | 484 | } |
d4d5291c | 485 | EXPORT_SYMBOL_GPL(wait_for_device_probe); |
216773a7 | 486 | |
d779249e GKH |
487 | /** |
488 | * driver_probe_device - attempt to bind device & driver together | |
489 | * @drv: driver to bind a device to | |
490 | * @dev: device to try to bind to the driver | |
491 | * | |
49b420a1 | 492 | * This function returns -ENODEV if the device is not registered, |
af901ca1 | 493 | * 1 if the device is bound successfully and 0 otherwise. |
d779249e | 494 | * |
8e9394ce GKH |
495 | * This function must be called with @dev lock held. When called for a |
496 | * USB interface, @dev->parent lock must be held as well. | |
ddef08dd RW |
497 | * |
498 | * If the device has a parent, runtime-resume the parent before driver probing. | |
d779249e | 499 | */ |
4a3ad20c | 500 | int driver_probe_device(struct device_driver *drv, struct device *dev) |
d779249e | 501 | { |
d779249e GKH |
502 | int ret = 0; |
503 | ||
f2eaae19 AS |
504 | if (!device_is_registered(dev)) |
505 | return -ENODEV; | |
d779249e | 506 | |
7dc72b28 | 507 | pr_debug("bus: '%s': %s: matched device %s with driver %s\n", |
1e0b2cf9 | 508 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 509 | |
ddef08dd RW |
510 | if (dev->parent) |
511 | pm_runtime_get_sync(dev->parent); | |
512 | ||
5e928f77 | 513 | pm_runtime_barrier(dev); |
21c7f30b | 514 | ret = really_probe(dev, drv); |
fa180eb4 | 515 | pm_request_idle(dev); |
d779249e | 516 | |
ddef08dd RW |
517 | if (dev->parent) |
518 | pm_runtime_put(dev->parent); | |
519 | ||
0d3e5a2e | 520 | return ret; |
07e4a3e2 | 521 | } |
522 | ||
765230b5 | 523 | bool driver_allows_async_probing(struct device_driver *drv) |
2287c322 | 524 | { |
d173a137 LR |
525 | switch (drv->probe_type) { |
526 | case PROBE_PREFER_ASYNCHRONOUS: | |
f2411da7 LR |
527 | return true; |
528 | ||
d173a137 LR |
529 | case PROBE_FORCE_SYNCHRONOUS: |
530 | return false; | |
531 | ||
532 | default: | |
80c6e146 | 533 | if (module_requested_async_probing(drv->owner)) |
d173a137 | 534 | return true; |
f2411da7 | 535 | |
d173a137 LR |
536 | return false; |
537 | } | |
765230b5 DT |
538 | } |
539 | ||
540 | struct device_attach_data { | |
541 | struct device *dev; | |
542 | ||
543 | /* | |
544 | * Indicates whether we are are considering asynchronous probing or | |
545 | * not. Only initial binding after device or driver registration | |
546 | * (including deferral processing) may be done asynchronously, the | |
547 | * rest is always synchronous, as we expect it is being done by | |
548 | * request from userspace. | |
549 | */ | |
550 | bool check_async; | |
551 | ||
552 | /* | |
553 | * Indicates if we are binding synchronous or asynchronous drivers. | |
554 | * When asynchronous probing is enabled we'll execute 2 passes | |
555 | * over drivers: first pass doing synchronous probing and second | |
556 | * doing asynchronous probing (if synchronous did not succeed - | |
557 | * most likely because there was no driver requiring synchronous | |
558 | * probing - and we found asynchronous driver during first pass). | |
559 | * The 2 passes are done because we can't shoot asynchronous | |
560 | * probe for given device and driver from bus_for_each_drv() since | |
561 | * driver pointer is not guaranteed to stay valid once | |
562 | * bus_for_each_drv() iterates to the next driver on the bus. | |
563 | */ | |
564 | bool want_async; | |
565 | ||
566 | /* | |
567 | * We'll set have_async to 'true' if, while scanning for matching | |
568 | * driver, we'll encounter one that requests asynchronous probing. | |
569 | */ | |
570 | bool have_async; | |
571 | }; | |
572 | ||
573 | static int __device_attach_driver(struct device_driver *drv, void *_data) | |
574 | { | |
575 | struct device_attach_data *data = _data; | |
576 | struct device *dev = data->dev; | |
577 | bool async_allowed; | |
656b8035 | 578 | int ret; |
765230b5 DT |
579 | |
580 | /* | |
581 | * Check if device has already been claimed. This may | |
582 | * happen with driver loading, device discovery/registration, | |
583 | * and deferred probe processing happens all at once with | |
584 | * multiple threads. | |
585 | */ | |
586 | if (dev->driver) | |
587 | return -EBUSY; | |
49b420a1 | 588 | |
656b8035 TV |
589 | ret = driver_match_device(drv, dev); |
590 | if (ret == 0) { | |
591 | /* no match */ | |
49b420a1 | 592 | return 0; |
656b8035 TV |
593 | } else if (ret == -EPROBE_DEFER) { |
594 | dev_dbg(dev, "Device match requests probe deferral\n"); | |
595 | driver_deferred_probe_add(dev); | |
596 | } else if (ret < 0) { | |
597 | dev_dbg(dev, "Bus failed to match device: %d", ret); | |
598 | return ret; | |
599 | } /* ret > 0 means positive match */ | |
49b420a1 | 600 | |
765230b5 DT |
601 | async_allowed = driver_allows_async_probing(drv); |
602 | ||
603 | if (async_allowed) | |
604 | data->have_async = true; | |
605 | ||
606 | if (data->check_async && async_allowed != data->want_async) | |
607 | return 0; | |
608 | ||
0d3e5a2e | 609 | return driver_probe_device(drv, dev); |
2287c322 | 610 | } |
611 | ||
765230b5 DT |
612 | static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) |
613 | { | |
614 | struct device *dev = _dev; | |
615 | struct device_attach_data data = { | |
616 | .dev = dev, | |
617 | .check_async = true, | |
618 | .want_async = true, | |
619 | }; | |
620 | ||
621 | device_lock(dev); | |
622 | ||
ddef08dd RW |
623 | if (dev->parent) |
624 | pm_runtime_get_sync(dev->parent); | |
625 | ||
765230b5 DT |
626 | bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver); |
627 | dev_dbg(dev, "async probe completed\n"); | |
628 | ||
629 | pm_request_idle(dev); | |
630 | ||
ddef08dd RW |
631 | if (dev->parent) |
632 | pm_runtime_put(dev->parent); | |
633 | ||
765230b5 DT |
634 | device_unlock(dev); |
635 | ||
636 | put_device(dev); | |
637 | } | |
638 | ||
802a87fd | 639 | static int __device_attach(struct device *dev, bool allow_async) |
07e4a3e2 | 640 | { |
0d3e5a2e PM |
641 | int ret = 0; |
642 | ||
8e9394ce | 643 | device_lock(dev); |
07e4a3e2 | 644 | if (dev->driver) { |
6b9cb427 | 645 | if (device_is_bound(dev)) { |
8497d6a2 SO |
646 | ret = 1; |
647 | goto out_unlock; | |
648 | } | |
f86db396 AM |
649 | ret = device_bind_driver(dev); |
650 | if (ret == 0) | |
651 | ret = 1; | |
c6a46696 CH |
652 | else { |
653 | dev->driver = NULL; | |
654 | ret = 0; | |
655 | } | |
21c7f30b | 656 | } else { |
765230b5 DT |
657 | struct device_attach_data data = { |
658 | .dev = dev, | |
659 | .check_async = allow_async, | |
660 | .want_async = false, | |
661 | }; | |
662 | ||
ddef08dd RW |
663 | if (dev->parent) |
664 | pm_runtime_get_sync(dev->parent); | |
665 | ||
765230b5 DT |
666 | ret = bus_for_each_drv(dev->bus, NULL, &data, |
667 | __device_attach_driver); | |
668 | if (!ret && allow_async && data.have_async) { | |
669 | /* | |
670 | * If we could not find appropriate driver | |
671 | * synchronously and we are allowed to do | |
672 | * async probes and there are drivers that | |
673 | * want to probe asynchronously, we'll | |
674 | * try them. | |
675 | */ | |
676 | dev_dbg(dev, "scheduling asynchronous probe\n"); | |
677 | get_device(dev); | |
678 | async_schedule(__device_attach_async_helper, dev); | |
679 | } else { | |
680 | pm_request_idle(dev); | |
681 | } | |
ddef08dd RW |
682 | |
683 | if (dev->parent) | |
684 | pm_runtime_put(dev->parent); | |
21c7f30b | 685 | } |
8497d6a2 | 686 | out_unlock: |
8e9394ce | 687 | device_unlock(dev); |
0d3e5a2e | 688 | return ret; |
2287c322 | 689 | } |
765230b5 DT |
690 | |
691 | /** | |
692 | * device_attach - try to attach device to a driver. | |
693 | * @dev: device. | |
694 | * | |
695 | * Walk the list of drivers that the bus has and call | |
696 | * driver_probe_device() for each pair. If a compatible | |
697 | * pair is found, break out and return. | |
698 | * | |
699 | * Returns 1 if the device was bound to a driver; | |
700 | * 0 if no matching driver was found; | |
701 | * -ENODEV if the device is not registered. | |
702 | * | |
703 | * When called for a USB interface, @dev->parent lock must be held. | |
704 | */ | |
705 | int device_attach(struct device *dev) | |
706 | { | |
707 | return __device_attach(dev, false); | |
708 | } | |
4a3ad20c | 709 | EXPORT_SYMBOL_GPL(device_attach); |
2287c322 | 710 | |
765230b5 DT |
711 | void device_initial_probe(struct device *dev) |
712 | { | |
713 | __device_attach(dev, true); | |
714 | } | |
715 | ||
4a3ad20c | 716 | static int __driver_attach(struct device *dev, void *data) |
2287c322 | 717 | { |
4a3ad20c | 718 | struct device_driver *drv = data; |
656b8035 | 719 | int ret; |
0d3e5a2e PM |
720 | |
721 | /* | |
722 | * Lock device and try to bind to it. We drop the error | |
723 | * here and always return 0, because we need to keep trying | |
724 | * to bind to devices and some drivers will return an error | |
725 | * simply if it didn't support the device. | |
726 | * | |
727 | * driver_probe_device() will spit a warning if there | |
728 | * is an error. | |
729 | */ | |
730 | ||
656b8035 TV |
731 | ret = driver_match_device(drv, dev); |
732 | if (ret == 0) { | |
733 | /* no match */ | |
6cd49586 | 734 | return 0; |
656b8035 TV |
735 | } else if (ret == -EPROBE_DEFER) { |
736 | dev_dbg(dev, "Device match requests probe deferral\n"); | |
737 | driver_deferred_probe_add(dev); | |
738 | } else if (ret < 0) { | |
739 | dev_dbg(dev, "Bus failed to match device: %d", ret); | |
740 | return ret; | |
741 | } /* ret > 0 means positive match */ | |
6cd49586 | 742 | |
bf74ad5b | 743 | if (dev->parent) /* Needed for USB */ |
8e9394ce GKH |
744 | device_lock(dev->parent); |
745 | device_lock(dev); | |
0d3e5a2e PM |
746 | if (!dev->driver) |
747 | driver_probe_device(drv, dev); | |
8e9394ce | 748 | device_unlock(dev); |
bf74ad5b | 749 | if (dev->parent) |
8e9394ce | 750 | device_unlock(dev->parent); |
0d3e5a2e | 751 | |
07e4a3e2 | 752 | return 0; |
753 | } | |
754 | ||
755 | /** | |
4a3ad20c GKH |
756 | * driver_attach - try to bind driver to devices. |
757 | * @drv: driver. | |
07e4a3e2 | 758 | * |
4a3ad20c GKH |
759 | * Walk the list of devices that the bus has on it and try to |
760 | * match the driver with each one. If driver_probe_device() | |
761 | * returns 0 and the @dev->driver is set, we've found a | |
762 | * compatible pair. | |
07e4a3e2 | 763 | */ |
4a3ad20c | 764 | int driver_attach(struct device_driver *drv) |
07e4a3e2 | 765 | { |
f86db396 | 766 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 767 | } |
4a3ad20c | 768 | EXPORT_SYMBOL_GPL(driver_attach); |
07e4a3e2 | 769 | |
ab71c6f0 | 770 | /* |
8e9394ce GKH |
771 | * __device_release_driver() must be called with @dev lock held. |
772 | * When called for a USB interface, @dev->parent lock must be held as well. | |
07e4a3e2 | 773 | */ |
4a3ad20c | 774 | static void __device_release_driver(struct device *dev) |
07e4a3e2 | 775 | { |
4a3ad20c | 776 | struct device_driver *drv; |
07e4a3e2 | 777 | |
ef2c5174 | 778 | drv = dev->driver; |
c95a6b05 | 779 | if (drv) { |
765230b5 DT |
780 | if (driver_allows_async_probing(drv)) |
781 | async_synchronize_full(); | |
782 | ||
e1866b33 | 783 | pm_runtime_get_sync(dev); |
5e928f77 | 784 | |
1901fb26 | 785 | driver_sysfs_remove(dev); |
0d3e5a2e | 786 | |
116af378 | 787 | if (dev->bus) |
c6f7e72a | 788 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
789 | BUS_NOTIFY_UNBIND_DRIVER, |
790 | dev); | |
791 | ||
baab52de | 792 | pm_runtime_put_sync(dev); |
e1866b33 | 793 | |
0f836ca4 | 794 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
795 | dev->bus->remove(dev); |
796 | else if (drv->remove) | |
0d3e5a2e | 797 | drv->remove(dev); |
9ac7849e | 798 | devres_release_all(dev); |
0d3e5a2e | 799 | dev->driver = NULL; |
0998d063 | 800 | dev_set_drvdata(dev, NULL); |
e90d5532 RW |
801 | if (dev->pm_domain && dev->pm_domain->dismiss) |
802 | dev->pm_domain->dismiss(dev); | |
5de85b9d | 803 | pm_runtime_reinit(dev); |
e90d5532 | 804 | |
8940b4f3 | 805 | klist_remove(&dev->p->knode_driver); |
aa8e54b5 | 806 | device_pm_check_callbacks(dev); |
309b7d60 JR |
807 | if (dev->bus) |
808 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
809 | BUS_NOTIFY_UNBOUND_DRIVER, | |
810 | dev); | |
0d3e5a2e | 811 | } |
07e4a3e2 | 812 | } |
813 | ||
ab71c6f0 | 814 | /** |
4a3ad20c GKH |
815 | * device_release_driver - manually detach device from driver. |
816 | * @dev: device. | |
ab71c6f0 | 817 | * |
4a3ad20c | 818 | * Manually detach device from driver. |
8e9394ce | 819 | * When called for a USB interface, @dev->parent lock must be held. |
ab71c6f0 | 820 | */ |
4a3ad20c | 821 | void device_release_driver(struct device *dev) |
94e7b1c5 | 822 | { |
c95a6b05 AS |
823 | /* |
824 | * If anyone calls device_release_driver() recursively from | |
825 | * within their ->remove callback for the same device, they | |
826 | * will deadlock right here. | |
827 | */ | |
8e9394ce | 828 | device_lock(dev); |
c95a6b05 | 829 | __device_release_driver(dev); |
8e9394ce | 830 | device_unlock(dev); |
94e7b1c5 | 831 | } |
4a3ad20c | 832 | EXPORT_SYMBOL_GPL(device_release_driver); |
c95a6b05 | 833 | |
07e4a3e2 | 834 | /** |
835 | * driver_detach - detach driver from all devices it controls. | |
836 | * @drv: driver. | |
837 | */ | |
4a3ad20c | 838 | void driver_detach(struct device_driver *drv) |
07e4a3e2 | 839 | { |
8940b4f3 | 840 | struct device_private *dev_prv; |
4a3ad20c | 841 | struct device *dev; |
c95a6b05 AS |
842 | |
843 | for (;;) { | |
e5dd1278 GKH |
844 | spin_lock(&drv->p->klist_devices.k_lock); |
845 | if (list_empty(&drv->p->klist_devices.k_list)) { | |
846 | spin_unlock(&drv->p->klist_devices.k_lock); | |
c95a6b05 AS |
847 | break; |
848 | } | |
8940b4f3 GKH |
849 | dev_prv = list_entry(drv->p->klist_devices.k_list.prev, |
850 | struct device_private, | |
851 | knode_driver.n_node); | |
852 | dev = dev_prv->device; | |
c95a6b05 | 853 | get_device(dev); |
e5dd1278 | 854 | spin_unlock(&drv->p->klist_devices.k_lock); |
c95a6b05 | 855 | |
bf74ad5b | 856 | if (dev->parent) /* Needed for USB */ |
8e9394ce GKH |
857 | device_lock(dev->parent); |
858 | device_lock(dev); | |
c95a6b05 AS |
859 | if (dev->driver == drv) |
860 | __device_release_driver(dev); | |
8e9394ce | 861 | device_unlock(dev); |
bf74ad5b | 862 | if (dev->parent) |
8e9394ce | 863 | device_unlock(dev->parent); |
c95a6b05 AS |
864 | put_device(dev); |
865 | } | |
07e4a3e2 | 866 | } |