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Commit | Line | Data |
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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 PM |
18 | */ |
19 | ||
20 | #include <linux/device.h> | |
216773a7 | 21 | #include <linux/delay.h> |
09515ef5 | 22 | #include <linux/dma-mapping.h> |
1f5000bd | 23 | #include <linux/init.h> |
07e4a3e2 | 24 | #include <linux/module.h> |
d779249e | 25 | #include <linux/kthread.h> |
735a7ffb | 26 | #include <linux/wait.h> |
216773a7 | 27 | #include <linux/async.h> |
5e928f77 | 28 | #include <linux/pm_runtime.h> |
ab78029e | 29 | #include <linux/pinctrl/devinfo.h> |
07e4a3e2 PM |
30 | |
31 | #include "base.h" | |
32 | #include "power/power.h" | |
33 | ||
d1c3414c GL |
34 | /* |
35 | * Deferred Probe infrastructure. | |
36 | * | |
37 | * Sometimes driver probe order matters, but the kernel doesn't always have | |
38 | * dependency information which means some drivers will get probed before a | |
39 | * resource it depends on is available. For example, an SDHCI driver may | |
40 | * first need a GPIO line from an i2c GPIO controller before it can be | |
41 | * initialized. If a required resource is not available yet, a driver can | |
42 | * request probing to be deferred by returning -EPROBE_DEFER from its probe hook | |
43 | * | |
44 | * Deferred probe maintains two lists of devices, a pending list and an active | |
45 | * list. A driver returning -EPROBE_DEFER causes the device to be added to the | |
46 | * pending list. A successful driver probe will trigger moving all devices | |
47 | * from the pending to the active list so that the workqueue will eventually | |
48 | * retry them. | |
49 | * | |
50 | * The deferred_probe_mutex must be held any time the deferred_probe_*_list | |
ef8a3fd6 | 51 | * of the (struct device*)->p->deferred_probe pointers are manipulated |
d1c3414c GL |
52 | */ |
53 | static DEFINE_MUTEX(deferred_probe_mutex); | |
54 | static LIST_HEAD(deferred_probe_pending_list); | |
55 | static LIST_HEAD(deferred_probe_active_list); | |
58b116bc | 56 | static atomic_t deferred_trigger_count = ATOMIC_INIT(0); |
1f5000bd | 57 | static bool initcalls_done; |
d1c3414c | 58 | |
013c074f SG |
59 | /* |
60 | * In some cases, like suspend to RAM or hibernation, It might be reasonable | |
61 | * to prohibit probing of devices as it could be unsafe. | |
62 | * Once defer_all_probes is true all drivers probes will be forcibly deferred. | |
63 | */ | |
64 | static bool defer_all_probes; | |
65 | ||
1f5000bd TP |
66 | /* |
67 | * For initcall_debug, show the deferred probes executed in late_initcall | |
68 | * processing. | |
69 | */ | |
70 | static void deferred_probe_debug(struct device *dev) | |
71 | { | |
72 | ktime_t calltime, delta, rettime; | |
73 | unsigned long long duration; | |
74 | ||
75 | printk(KERN_DEBUG "deferred probe %s @ %i\n", dev_name(dev), | |
76 | task_pid_nr(current)); | |
77 | calltime = ktime_get(); | |
78 | bus_probe_device(dev); | |
79 | rettime = ktime_get(); | |
80 | delta = ktime_sub(rettime, calltime); | |
81 | duration = (unsigned long long) ktime_to_ns(delta) >> 10; | |
82 | printk(KERN_DEBUG "deferred probe %s returned after %lld usecs\n", | |
83 | dev_name(dev), duration); | |
84 | } | |
85 | ||
41575335 | 86 | /* |
d1c3414c GL |
87 | * deferred_probe_work_func() - Retry probing devices in the active list. |
88 | */ | |
89 | static void deferred_probe_work_func(struct work_struct *work) | |
90 | { | |
91 | struct device *dev; | |
ef8a3fd6 | 92 | struct device_private *private; |
d1c3414c GL |
93 | /* |
94 | * This block processes every device in the deferred 'active' list. | |
95 | * Each device is removed from the active list and passed to | |
96 | * bus_probe_device() to re-attempt the probe. The loop continues | |
97 | * until every device in the active list is removed and retried. | |
98 | * | |
99 | * Note: Once the device is removed from the list and the mutex is | |
100 | * released, it is possible for the device get freed by another thread | |
101 | * and cause a illegal pointer dereference. This code uses | |
102 | * get/put_device() to ensure the device structure cannot disappear | |
103 | * from under our feet. | |
104 | */ | |
105 | mutex_lock(&deferred_probe_mutex); | |
106 | while (!list_empty(&deferred_probe_active_list)) { | |
ef8a3fd6 GKH |
107 | private = list_first_entry(&deferred_probe_active_list, |
108 | typeof(*dev->p), deferred_probe); | |
109 | dev = private->device; | |
110 | list_del_init(&private->deferred_probe); | |
d1c3414c GL |
111 | |
112 | get_device(dev); | |
113 | ||
8b0372a2 GKH |
114 | /* |
115 | * Drop the mutex while probing each device; the probe path may | |
116 | * manipulate the deferred list | |
117 | */ | |
d1c3414c | 118 | mutex_unlock(&deferred_probe_mutex); |
8153584e MB |
119 | |
120 | /* | |
121 | * Force the device to the end of the dpm_list since | |
122 | * the PM code assumes that the order we add things to | |
123 | * the list is a good order for suspend but deferred | |
124 | * probe makes that very unsafe. | |
125 | */ | |
126 | device_pm_lock(); | |
127 | device_pm_move_last(dev); | |
128 | device_pm_unlock(); | |
129 | ||
d1c3414c | 130 | dev_dbg(dev, "Retrying from deferred list\n"); |
1f5000bd TP |
131 | if (initcall_debug && !initcalls_done) |
132 | deferred_probe_debug(dev); | |
133 | else | |
134 | bus_probe_device(dev); | |
8153584e | 135 | |
d1c3414c GL |
136 | mutex_lock(&deferred_probe_mutex); |
137 | ||
138 | put_device(dev); | |
139 | } | |
140 | mutex_unlock(&deferred_probe_mutex); | |
141 | } | |
142 | static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); | |
143 | ||
144 | static void driver_deferred_probe_add(struct device *dev) | |
145 | { | |
146 | mutex_lock(&deferred_probe_mutex); | |
ef8a3fd6 | 147 | if (list_empty(&dev->p->deferred_probe)) { |
d1c3414c | 148 | dev_dbg(dev, "Added to deferred list\n"); |
1d29cfa5 | 149 | list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list); |
d1c3414c GL |
150 | } |
151 | mutex_unlock(&deferred_probe_mutex); | |
152 | } | |
153 | ||
154 | void driver_deferred_probe_del(struct device *dev) | |
155 | { | |
156 | mutex_lock(&deferred_probe_mutex); | |
ef8a3fd6 | 157 | if (!list_empty(&dev->p->deferred_probe)) { |
d1c3414c | 158 | dev_dbg(dev, "Removed from deferred list\n"); |
ef8a3fd6 | 159 | list_del_init(&dev->p->deferred_probe); |
d1c3414c GL |
160 | } |
161 | mutex_unlock(&deferred_probe_mutex); | |
162 | } | |
163 | ||
164 | static bool driver_deferred_probe_enable = false; | |
165 | /** | |
166 | * driver_deferred_probe_trigger() - Kick off re-probing deferred devices | |
167 | * | |
168 | * This functions moves all devices from the pending list to the active | |
169 | * list and schedules the deferred probe workqueue to process them. It | |
170 | * should be called anytime a driver is successfully bound to a device. | |
58b116bc GL |
171 | * |
172 | * Note, there is a race condition in multi-threaded probe. In the case where | |
173 | * more than one device is probing at the same time, it is possible for one | |
174 | * probe to complete successfully while another is about to defer. If the second | |
175 | * depends on the first, then it will get put on the pending list after the | |
9ba8af66 | 176 | * trigger event has already occurred and will be stuck there. |
58b116bc GL |
177 | * |
178 | * The atomic 'deferred_trigger_count' is used to determine if a successful | |
179 | * trigger has occurred in the midst of probing a driver. If the trigger count | |
180 | * changes in the midst of a probe, then deferred processing should be triggered | |
181 | * again. | |
d1c3414c GL |
182 | */ |
183 | static void driver_deferred_probe_trigger(void) | |
184 | { | |
185 | if (!driver_deferred_probe_enable) | |
186 | return; | |
187 | ||
8b0372a2 GKH |
188 | /* |
189 | * A successful probe means that all the devices in the pending list | |
d1c3414c | 190 | * should be triggered to be reprobed. Move all the deferred devices |
8b0372a2 GKH |
191 | * into the active list so they can be retried by the workqueue |
192 | */ | |
d1c3414c | 193 | mutex_lock(&deferred_probe_mutex); |
58b116bc | 194 | atomic_inc(&deferred_trigger_count); |
d1c3414c GL |
195 | list_splice_tail_init(&deferred_probe_pending_list, |
196 | &deferred_probe_active_list); | |
197 | mutex_unlock(&deferred_probe_mutex); | |
198 | ||
8b0372a2 GKH |
199 | /* |
200 | * Kick the re-probe thread. It may already be scheduled, but it is | |
201 | * safe to kick it again. | |
202 | */ | |
2c507e46 | 203 | schedule_work(&deferred_probe_work); |
d1c3414c GL |
204 | } |
205 | ||
013c074f SG |
206 | /** |
207 | * device_block_probing() - Block/defere device's probes | |
208 | * | |
209 | * It will disable probing of devices and defer their probes instead. | |
210 | */ | |
211 | void device_block_probing(void) | |
212 | { | |
213 | defer_all_probes = true; | |
214 | /* sync with probes to avoid races. */ | |
215 | wait_for_device_probe(); | |
216 | } | |
217 | ||
218 | /** | |
219 | * device_unblock_probing() - Unblock/enable device's probes | |
220 | * | |
221 | * It will restore normal behavior and trigger re-probing of deferred | |
222 | * devices. | |
223 | */ | |
224 | void device_unblock_probing(void) | |
225 | { | |
226 | defer_all_probes = false; | |
227 | driver_deferred_probe_trigger(); | |
228 | } | |
229 | ||
d1c3414c GL |
230 | /** |
231 | * deferred_probe_initcall() - Enable probing of deferred devices | |
232 | * | |
233 | * We don't want to get in the way when the bulk of drivers are getting probed. | |
234 | * Instead, this initcall makes sure that deferred probing is delayed until | |
235 | * late_initcall time. | |
236 | */ | |
237 | static int deferred_probe_initcall(void) | |
238 | { | |
d1c3414c GL |
239 | driver_deferred_probe_enable = true; |
240 | driver_deferred_probe_trigger(); | |
d72cca1e | 241 | /* Sort as many dependencies as possible before exiting initcalls */ |
2c507e46 | 242 | flush_work(&deferred_probe_work); |
1f5000bd | 243 | initcalls_done = true; |
d1c3414c GL |
244 | return 0; |
245 | } | |
246 | late_initcall(deferred_probe_initcall); | |
07e4a3e2 | 247 | |
6b9cb427 TV |
248 | /** |
249 | * device_is_bound() - Check if device is bound to a driver | |
250 | * @dev: device to check | |
251 | * | |
252 | * Returns true if passed device has already finished probing successfully | |
253 | * against a driver. | |
254 | * | |
255 | * This function must be called with the device lock held. | |
256 | */ | |
257 | bool device_is_bound(struct device *dev) | |
258 | { | |
3ded9104 | 259 | return dev->p && klist_node_attached(&dev->p->knode_driver); |
6b9cb427 TV |
260 | } |
261 | ||
1901fb26 | 262 | static void driver_bound(struct device *dev) |
07e4a3e2 | 263 | { |
6b9cb427 | 264 | if (device_is_bound(dev)) { |
f86db396 | 265 | printk(KERN_WARNING "%s: device %s already bound\n", |
2b3a302a | 266 | __func__, kobject_name(&dev->kobj)); |
1901fb26 | 267 | return; |
f86db396 | 268 | } |
4c898c7f | 269 | |
94f8cc0e FR |
270 | pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name, |
271 | __func__, dev_name(dev)); | |
116af378 | 272 | |
fbb88fad | 273 | klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); |
9ed98953 | 274 | device_links_driver_bound(dev); |
fbb88fad | 275 | |
aa8e54b5 TV |
276 | device_pm_check_callbacks(dev); |
277 | ||
8b0372a2 GKH |
278 | /* |
279 | * Make sure the device is no longer in one of the deferred lists and | |
280 | * kick off retrying all pending devices | |
281 | */ | |
d1c3414c GL |
282 | driver_deferred_probe_del(dev); |
283 | driver_deferred_probe_trigger(); | |
284 | ||
116af378 | 285 | if (dev->bus) |
c6f7e72a | 286 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 | 287 | BUS_NOTIFY_BOUND_DRIVER, dev); |
1455cf8d DT |
288 | |
289 | kobject_uevent(&dev->kobj, KOBJ_BIND); | |
1901fb26 KS |
290 | } |
291 | ||
292 | static int driver_sysfs_add(struct device *dev) | |
293 | { | |
294 | int ret; | |
295 | ||
45daef0f MD |
296 | if (dev->bus) |
297 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
298 | BUS_NOTIFY_BIND_DRIVER, dev); | |
299 | ||
e5dd1278 | 300 | ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
07e4a3e2 | 301 | kobject_name(&dev->kobj)); |
f86db396 | 302 | if (ret == 0) { |
e5dd1278 | 303 | ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
f86db396 AM |
304 | "driver"); |
305 | if (ret) | |
e5dd1278 | 306 | sysfs_remove_link(&dev->driver->p->kobj, |
f86db396 AM |
307 | kobject_name(&dev->kobj)); |
308 | } | |
309 | return ret; | |
07e4a3e2 PM |
310 | } |
311 | ||
1901fb26 KS |
312 | static void driver_sysfs_remove(struct device *dev) |
313 | { | |
314 | struct device_driver *drv = dev->driver; | |
315 | ||
316 | if (drv) { | |
e5dd1278 | 317 | sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
1901fb26 KS |
318 | sysfs_remove_link(&dev->kobj, "driver"); |
319 | } | |
320 | } | |
321 | ||
322 | /** | |
4a3ad20c GKH |
323 | * device_bind_driver - bind a driver to one device. |
324 | * @dev: device. | |
1901fb26 | 325 | * |
4a3ad20c GKH |
326 | * Allow manual attachment of a driver to a device. |
327 | * Caller must have already set @dev->driver. | |
1901fb26 | 328 | * |
4a3ad20c GKH |
329 | * Note that this does not modify the bus reference count |
330 | * nor take the bus's rwsem. Please verify those are accounted | |
331 | * for before calling this. (It is ok to call with no other effort | |
332 | * from a driver's probe() method.) | |
1901fb26 | 333 | * |
8e9394ce | 334 | * This function must be called with the device lock held. |
1901fb26 KS |
335 | */ |
336 | int device_bind_driver(struct device *dev) | |
337 | { | |
cb986b74 CH |
338 | int ret; |
339 | ||
340 | ret = driver_sysfs_add(dev); | |
341 | if (!ret) | |
342 | driver_bound(dev); | |
14b6257a AS |
343 | else if (dev->bus) |
344 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
345 | BUS_NOTIFY_DRIVER_NOT_BOUND, dev); | |
cb986b74 | 346 | return ret; |
1901fb26 | 347 | } |
4a3ad20c | 348 | EXPORT_SYMBOL_GPL(device_bind_driver); |
1901fb26 | 349 | |
d779249e | 350 | static atomic_t probe_count = ATOMIC_INIT(0); |
735a7ffb AM |
351 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
352 | ||
0ff26c66 AH |
353 | static void driver_deferred_probe_add_trigger(struct device *dev, |
354 | int local_trigger_count) | |
355 | { | |
356 | driver_deferred_probe_add(dev); | |
357 | /* Did a trigger occur while probing? Need to re-trigger if yes */ | |
358 | if (local_trigger_count != atomic_read(&deferred_trigger_count)) | |
359 | driver_deferred_probe_trigger(); | |
360 | } | |
361 | ||
21c7f30b | 362 | static int really_probe(struct device *dev, struct device_driver *drv) |
07e4a3e2 | 363 | { |
013c074f | 364 | int ret = -EPROBE_DEFER; |
58b116bc | 365 | int local_trigger_count = atomic_read(&deferred_trigger_count); |
c5f06274 RH |
366 | bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) && |
367 | !drv->suppress_bind_attrs; | |
07e4a3e2 | 368 | |
013c074f SG |
369 | if (defer_all_probes) { |
370 | /* | |
371 | * Value of defer_all_probes can be set only by | |
372 | * device_defer_all_probes_enable() which, in turn, will call | |
373 | * wait_for_device_probe() right after that to avoid any races. | |
374 | */ | |
375 | dev_dbg(dev, "Driver %s force probe deferral\n", drv->name); | |
376 | driver_deferred_probe_add(dev); | |
377 | return ret; | |
378 | } | |
379 | ||
9ed98953 | 380 | ret = device_links_check_suppliers(dev); |
0ff26c66 AH |
381 | if (ret == -EPROBE_DEFER) |
382 | driver_deferred_probe_add_trigger(dev, local_trigger_count); | |
9ed98953 RW |
383 | if (ret) |
384 | return ret; | |
385 | ||
d779249e | 386 | atomic_inc(&probe_count); |
7dc72b28 | 387 | pr_debug("bus: '%s': %s: probing driver %s with device %s\n", |
1e0b2cf9 | 388 | drv->bus->name, __func__, drv->name, dev_name(dev)); |
9ac7849e | 389 | WARN_ON(!list_empty(&dev->devres_head)); |
07e4a3e2 | 390 | |
bea5b158 | 391 | re_probe: |
07e4a3e2 | 392 | dev->driver = drv; |
ab78029e LW |
393 | |
394 | /* If using pinctrl, bind pins now before probing */ | |
395 | ret = pinctrl_bind_pins(dev); | |
396 | if (ret) | |
14b6257a | 397 | goto pinctrl_bind_failed; |
ab78029e | 398 | |
09515ef5 S |
399 | ret = dma_configure(dev); |
400 | if (ret) | |
401 | goto dma_failed; | |
402 | ||
1901fb26 KS |
403 | if (driver_sysfs_add(dev)) { |
404 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
1e0b2cf9 | 405 | __func__, dev_name(dev)); |
1901fb26 KS |
406 | goto probe_failed; |
407 | } | |
408 | ||
e90d5532 RW |
409 | if (dev->pm_domain && dev->pm_domain->activate) { |
410 | ret = dev->pm_domain->activate(dev); | |
411 | if (ret) | |
412 | goto probe_failed; | |
413 | } | |
414 | ||
594c8281 RK |
415 | if (dev->bus->probe) { |
416 | ret = dev->bus->probe(dev); | |
1901fb26 | 417 | if (ret) |
d779249e | 418 | goto probe_failed; |
594c8281 | 419 | } else if (drv->probe) { |
0d3e5a2e | 420 | ret = drv->probe(dev); |
1901fb26 | 421 | if (ret) |
d779249e | 422 | goto probe_failed; |
f86db396 | 423 | } |
1901fb26 | 424 | |
bea5b158 RH |
425 | if (test_remove) { |
426 | test_remove = false; | |
427 | ||
bdacd1b4 | 428 | if (dev->bus->remove) |
bea5b158 RH |
429 | dev->bus->remove(dev); |
430 | else if (drv->remove) | |
431 | drv->remove(dev); | |
432 | ||
433 | devres_release_all(dev); | |
434 | driver_sysfs_remove(dev); | |
435 | dev->driver = NULL; | |
436 | dev_set_drvdata(dev, NULL); | |
437 | if (dev->pm_domain && dev->pm_domain->dismiss) | |
438 | dev->pm_domain->dismiss(dev); | |
439 | pm_runtime_reinit(dev); | |
440 | ||
441 | goto re_probe; | |
442 | } | |
443 | ||
ef0eebc0 DA |
444 | pinctrl_init_done(dev); |
445 | ||
e90d5532 RW |
446 | if (dev->pm_domain && dev->pm_domain->sync) |
447 | dev->pm_domain->sync(dev); | |
448 | ||
1901fb26 | 449 | driver_bound(dev); |
0d3e5a2e | 450 | ret = 1; |
7dc72b28 | 451 | pr_debug("bus: '%s': %s: bound device %s to driver %s\n", |
1e0b2cf9 | 452 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 453 | goto done; |
0d3e5a2e | 454 | |
d779249e | 455 | probe_failed: |
09515ef5 S |
456 | dma_deconfigure(dev); |
457 | dma_failed: | |
14b6257a AS |
458 | if (dev->bus) |
459 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
460 | BUS_NOTIFY_DRIVER_NOT_BOUND, dev); | |
461 | pinctrl_bind_failed: | |
9ed98953 | 462 | device_links_no_driver(dev); |
9ac7849e | 463 | devres_release_all(dev); |
1901fb26 KS |
464 | driver_sysfs_remove(dev); |
465 | dev->driver = NULL; | |
0998d063 | 466 | dev_set_drvdata(dev, NULL); |
e90d5532 RW |
467 | if (dev->pm_domain && dev->pm_domain->dismiss) |
468 | dev->pm_domain->dismiss(dev); | |
5de85b9d | 469 | pm_runtime_reinit(dev); |
08810a41 | 470 | dev_pm_set_driver_flags(dev, 0); |
1901fb26 | 471 | |
bb2b4075 SS |
472 | switch (ret) { |
473 | case -EPROBE_DEFER: | |
d1c3414c | 474 | /* Driver requested deferred probing */ |
13fcffbb | 475 | dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name); |
0ff26c66 | 476 | driver_deferred_probe_add_trigger(dev, local_trigger_count); |
bb2b4075 SS |
477 | break; |
478 | case -ENODEV: | |
479 | case -ENXIO: | |
480 | pr_debug("%s: probe of %s rejects match %d\n", | |
481 | drv->name, dev_name(dev), ret); | |
482 | break; | |
483 | default: | |
0d3e5a2e PM |
484 | /* driver matched but the probe failed */ |
485 | printk(KERN_WARNING | |
486 | "%s: probe of %s failed with error %d\n", | |
1e0b2cf9 | 487 | drv->name, dev_name(dev), ret); |
0d3e5a2e | 488 | } |
c578abbc CH |
489 | /* |
490 | * Ignore errors returned by ->probe so that the next driver can try | |
491 | * its luck. | |
492 | */ | |
493 | ret = 0; | |
d779249e | 494 | done: |
d779249e | 495 | atomic_dec(&probe_count); |
735a7ffb | 496 | wake_up(&probe_waitqueue); |
d779249e GKH |
497 | return ret; |
498 | } | |
499 | ||
500 | /** | |
501 | * driver_probe_done | |
502 | * Determine if the probe sequence is finished or not. | |
503 | * | |
504 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
505 | */ | |
506 | int driver_probe_done(void) | |
507 | { | |
2b3a302a | 508 | pr_debug("%s: probe_count = %d\n", __func__, |
d779249e GKH |
509 | atomic_read(&probe_count)); |
510 | if (atomic_read(&probe_count)) | |
511 | return -EBUSY; | |
512 | return 0; | |
513 | } | |
514 | ||
216773a7 AV |
515 | /** |
516 | * wait_for_device_probe | |
517 | * Wait for device probing to be completed. | |
216773a7 | 518 | */ |
b23530eb | 519 | void wait_for_device_probe(void) |
216773a7 | 520 | { |
013c074f | 521 | /* wait for the deferred probe workqueue to finish */ |
2c507e46 | 522 | flush_work(&deferred_probe_work); |
013c074f | 523 | |
216773a7 | 524 | /* wait for the known devices to complete their probing */ |
b23530eb | 525 | wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); |
216773a7 | 526 | async_synchronize_full(); |
216773a7 | 527 | } |
d4d5291c | 528 | EXPORT_SYMBOL_GPL(wait_for_device_probe); |
216773a7 | 529 | |
d779249e GKH |
530 | /** |
531 | * driver_probe_device - attempt to bind device & driver together | |
532 | * @drv: driver to bind a device to | |
533 | * @dev: device to try to bind to the driver | |
534 | * | |
49b420a1 | 535 | * This function returns -ENODEV if the device is not registered, |
af901ca1 | 536 | * 1 if the device is bound successfully and 0 otherwise. |
d779249e | 537 | * |
8e9394ce GKH |
538 | * This function must be called with @dev lock held. When called for a |
539 | * USB interface, @dev->parent lock must be held as well. | |
ddef08dd RW |
540 | * |
541 | * If the device has a parent, runtime-resume the parent before driver probing. | |
d779249e | 542 | */ |
4a3ad20c | 543 | int driver_probe_device(struct device_driver *drv, struct device *dev) |
d779249e | 544 | { |
d779249e GKH |
545 | int ret = 0; |
546 | ||
f2eaae19 AS |
547 | if (!device_is_registered(dev)) |
548 | return -ENODEV; | |
d779249e | 549 | |
7dc72b28 | 550 | pr_debug("bus: '%s': %s: matched device %s with driver %s\n", |
1e0b2cf9 | 551 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 552 | |
21d5c57b | 553 | pm_runtime_get_suppliers(dev); |
ddef08dd RW |
554 | if (dev->parent) |
555 | pm_runtime_get_sync(dev->parent); | |
556 | ||
5e928f77 | 557 | pm_runtime_barrier(dev); |
21c7f30b | 558 | ret = really_probe(dev, drv); |
fa180eb4 | 559 | pm_request_idle(dev); |
d779249e | 560 | |
ddef08dd RW |
561 | if (dev->parent) |
562 | pm_runtime_put(dev->parent); | |
563 | ||
21d5c57b | 564 | pm_runtime_put_suppliers(dev); |
0d3e5a2e | 565 | return ret; |
07e4a3e2 PM |
566 | } |
567 | ||
765230b5 | 568 | bool driver_allows_async_probing(struct device_driver *drv) |
2287c322 | 569 | { |
d173a137 LR |
570 | switch (drv->probe_type) { |
571 | case PROBE_PREFER_ASYNCHRONOUS: | |
f2411da7 LR |
572 | return true; |
573 | ||
d173a137 LR |
574 | case PROBE_FORCE_SYNCHRONOUS: |
575 | return false; | |
576 | ||
577 | default: | |
80c6e146 | 578 | if (module_requested_async_probing(drv->owner)) |
d173a137 | 579 | return true; |
f2411da7 | 580 | |
d173a137 LR |
581 | return false; |
582 | } | |
765230b5 DT |
583 | } |
584 | ||
585 | struct device_attach_data { | |
586 | struct device *dev; | |
587 | ||
588 | /* | |
589 | * Indicates whether we are are considering asynchronous probing or | |
590 | * not. Only initial binding after device or driver registration | |
591 | * (including deferral processing) may be done asynchronously, the | |
592 | * rest is always synchronous, as we expect it is being done by | |
593 | * request from userspace. | |
594 | */ | |
595 | bool check_async; | |
596 | ||
597 | /* | |
598 | * Indicates if we are binding synchronous or asynchronous drivers. | |
599 | * When asynchronous probing is enabled we'll execute 2 passes | |
600 | * over drivers: first pass doing synchronous probing and second | |
601 | * doing asynchronous probing (if synchronous did not succeed - | |
602 | * most likely because there was no driver requiring synchronous | |
603 | * probing - and we found asynchronous driver during first pass). | |
604 | * The 2 passes are done because we can't shoot asynchronous | |
605 | * probe for given device and driver from bus_for_each_drv() since | |
606 | * driver pointer is not guaranteed to stay valid once | |
607 | * bus_for_each_drv() iterates to the next driver on the bus. | |
608 | */ | |
609 | bool want_async; | |
610 | ||
611 | /* | |
612 | * We'll set have_async to 'true' if, while scanning for matching | |
613 | * driver, we'll encounter one that requests asynchronous probing. | |
614 | */ | |
615 | bool have_async; | |
616 | }; | |
617 | ||
618 | static int __device_attach_driver(struct device_driver *drv, void *_data) | |
619 | { | |
620 | struct device_attach_data *data = _data; | |
621 | struct device *dev = data->dev; | |
622 | bool async_allowed; | |
656b8035 | 623 | int ret; |
765230b5 DT |
624 | |
625 | /* | |
626 | * Check if device has already been claimed. This may | |
627 | * happen with driver loading, device discovery/registration, | |
628 | * and deferred probe processing happens all at once with | |
629 | * multiple threads. | |
630 | */ | |
631 | if (dev->driver) | |
632 | return -EBUSY; | |
49b420a1 | 633 | |
656b8035 TV |
634 | ret = driver_match_device(drv, dev); |
635 | if (ret == 0) { | |
636 | /* no match */ | |
49b420a1 | 637 | return 0; |
656b8035 TV |
638 | } else if (ret == -EPROBE_DEFER) { |
639 | dev_dbg(dev, "Device match requests probe deferral\n"); | |
640 | driver_deferred_probe_add(dev); | |
641 | } else if (ret < 0) { | |
642 | dev_dbg(dev, "Bus failed to match device: %d", ret); | |
643 | return ret; | |
644 | } /* ret > 0 means positive match */ | |
49b420a1 | 645 | |
765230b5 DT |
646 | async_allowed = driver_allows_async_probing(drv); |
647 | ||
648 | if (async_allowed) | |
649 | data->have_async = true; | |
650 | ||
651 | if (data->check_async && async_allowed != data->want_async) | |
652 | return 0; | |
653 | ||
0d3e5a2e | 654 | return driver_probe_device(drv, dev); |
2287c322 PM |
655 | } |
656 | ||
765230b5 DT |
657 | static void __device_attach_async_helper(void *_dev, async_cookie_t cookie) |
658 | { | |
659 | struct device *dev = _dev; | |
660 | struct device_attach_data data = { | |
661 | .dev = dev, | |
662 | .check_async = true, | |
663 | .want_async = true, | |
664 | }; | |
665 | ||
666 | device_lock(dev); | |
667 | ||
ddef08dd RW |
668 | if (dev->parent) |
669 | pm_runtime_get_sync(dev->parent); | |
670 | ||
765230b5 DT |
671 | bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver); |
672 | dev_dbg(dev, "async probe completed\n"); | |
673 | ||
674 | pm_request_idle(dev); | |
675 | ||
ddef08dd RW |
676 | if (dev->parent) |
677 | pm_runtime_put(dev->parent); | |
678 | ||
765230b5 DT |
679 | device_unlock(dev); |
680 | ||
681 | put_device(dev); | |
682 | } | |
683 | ||
802a87fd | 684 | static int __device_attach(struct device *dev, bool allow_async) |
07e4a3e2 | 685 | { |
0d3e5a2e PM |
686 | int ret = 0; |
687 | ||
8e9394ce | 688 | device_lock(dev); |
07e4a3e2 | 689 | if (dev->driver) { |
6b9cb427 | 690 | if (device_is_bound(dev)) { |
8497d6a2 SO |
691 | ret = 1; |
692 | goto out_unlock; | |
693 | } | |
f86db396 AM |
694 | ret = device_bind_driver(dev); |
695 | if (ret == 0) | |
696 | ret = 1; | |
c6a46696 CH |
697 | else { |
698 | dev->driver = NULL; | |
699 | ret = 0; | |
700 | } | |
21c7f30b | 701 | } else { |
765230b5 DT |
702 | struct device_attach_data data = { |
703 | .dev = dev, | |
704 | .check_async = allow_async, | |
705 | .want_async = false, | |
706 | }; | |
707 | ||
ddef08dd RW |
708 | if (dev->parent) |
709 | pm_runtime_get_sync(dev->parent); | |
710 | ||
765230b5 DT |
711 | ret = bus_for_each_drv(dev->bus, NULL, &data, |
712 | __device_attach_driver); | |
713 | if (!ret && allow_async && data.have_async) { | |
714 | /* | |
715 | * If we could not find appropriate driver | |
716 | * synchronously and we are allowed to do | |
717 | * async probes and there are drivers that | |
718 | * want to probe asynchronously, we'll | |
719 | * try them. | |
720 | */ | |
721 | dev_dbg(dev, "scheduling asynchronous probe\n"); | |
722 | get_device(dev); | |
723 | async_schedule(__device_attach_async_helper, dev); | |
724 | } else { | |
725 | pm_request_idle(dev); | |
726 | } | |
ddef08dd RW |
727 | |
728 | if (dev->parent) | |
729 | pm_runtime_put(dev->parent); | |
21c7f30b | 730 | } |
8497d6a2 | 731 | out_unlock: |
8e9394ce | 732 | device_unlock(dev); |
0d3e5a2e | 733 | return ret; |
2287c322 | 734 | } |
765230b5 DT |
735 | |
736 | /** | |
737 | * device_attach - try to attach device to a driver. | |
738 | * @dev: device. | |
739 | * | |
740 | * Walk the list of drivers that the bus has and call | |
741 | * driver_probe_device() for each pair. If a compatible | |
742 | * pair is found, break out and return. | |
743 | * | |
744 | * Returns 1 if the device was bound to a driver; | |
745 | * 0 if no matching driver was found; | |
746 | * -ENODEV if the device is not registered. | |
747 | * | |
748 | * When called for a USB interface, @dev->parent lock must be held. | |
749 | */ | |
750 | int device_attach(struct device *dev) | |
751 | { | |
752 | return __device_attach(dev, false); | |
753 | } | |
4a3ad20c | 754 | EXPORT_SYMBOL_GPL(device_attach); |
2287c322 | 755 | |
765230b5 DT |
756 | void device_initial_probe(struct device *dev) |
757 | { | |
758 | __device_attach(dev, true); | |
759 | } | |
760 | ||
4a3ad20c | 761 | static int __driver_attach(struct device *dev, void *data) |
2287c322 | 762 | { |
4a3ad20c | 763 | struct device_driver *drv = data; |
656b8035 | 764 | int ret; |
0d3e5a2e PM |
765 | |
766 | /* | |
767 | * Lock device and try to bind to it. We drop the error | |
768 | * here and always return 0, because we need to keep trying | |
769 | * to bind to devices and some drivers will return an error | |
770 | * simply if it didn't support the device. | |
771 | * | |
772 | * driver_probe_device() will spit a warning if there | |
773 | * is an error. | |
774 | */ | |
775 | ||
656b8035 TV |
776 | ret = driver_match_device(drv, dev); |
777 | if (ret == 0) { | |
778 | /* no match */ | |
6cd49586 | 779 | return 0; |
656b8035 TV |
780 | } else if (ret == -EPROBE_DEFER) { |
781 | dev_dbg(dev, "Device match requests probe deferral\n"); | |
782 | driver_deferred_probe_add(dev); | |
783 | } else if (ret < 0) { | |
784 | dev_dbg(dev, "Bus failed to match device: %d", ret); | |
785 | return ret; | |
786 | } /* ret > 0 means positive match */ | |
6cd49586 | 787 | |
bf74ad5b | 788 | if (dev->parent) /* Needed for USB */ |
8e9394ce GKH |
789 | device_lock(dev->parent); |
790 | device_lock(dev); | |
0d3e5a2e PM |
791 | if (!dev->driver) |
792 | driver_probe_device(drv, dev); | |
8e9394ce | 793 | device_unlock(dev); |
bf74ad5b | 794 | if (dev->parent) |
8e9394ce | 795 | device_unlock(dev->parent); |
0d3e5a2e | 796 | |
07e4a3e2 PM |
797 | return 0; |
798 | } | |
799 | ||
800 | /** | |
4a3ad20c GKH |
801 | * driver_attach - try to bind driver to devices. |
802 | * @drv: driver. | |
07e4a3e2 | 803 | * |
4a3ad20c GKH |
804 | * Walk the list of devices that the bus has on it and try to |
805 | * match the driver with each one. If driver_probe_device() | |
806 | * returns 0 and the @dev->driver is set, we've found a | |
807 | * compatible pair. | |
07e4a3e2 | 808 | */ |
4a3ad20c | 809 | int driver_attach(struct device_driver *drv) |
07e4a3e2 | 810 | { |
f86db396 | 811 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 812 | } |
4a3ad20c | 813 | EXPORT_SYMBOL_GPL(driver_attach); |
07e4a3e2 | 814 | |
5c727d0a AW |
815 | void *vfio_pci_driver_ptr = (void *)0xdeadfeed; |
816 | EXPORT_SYMBOL(vfio_pci_driver_ptr); | |
817 | ||
ab71c6f0 | 818 | /* |
8e9394ce GKH |
819 | * __device_release_driver() must be called with @dev lock held. |
820 | * When called for a USB interface, @dev->parent lock must be held as well. | |
07e4a3e2 | 821 | */ |
9ed98953 | 822 | static void __device_release_driver(struct device *dev, struct device *parent) |
07e4a3e2 | 823 | { |
4a3ad20c | 824 | struct device_driver *drv; |
07e4a3e2 | 825 | |
ef2c5174 | 826 | drv = dev->driver; |
c95a6b05 | 827 | if (drv) { |
765230b5 DT |
828 | if (driver_allows_async_probing(drv)) |
829 | async_synchronize_full(); | |
830 | ||
9ed98953 RW |
831 | while (device_links_busy(dev)) { |
832 | device_unlock(dev); | |
833 | if (parent) | |
834 | device_unlock(parent); | |
835 | ||
836 | device_links_unbind_consumers(dev); | |
837 | if (parent) | |
838 | device_lock(parent); | |
839 | ||
840 | device_lock(dev); | |
841 | /* | |
842 | * A concurrent invocation of the same function might | |
843 | * have released the driver successfully while this one | |
844 | * was waiting, so check for that. | |
845 | */ | |
846 | if (dev->driver != drv) | |
847 | return; | |
848 | } | |
849 | ||
e1866b33 | 850 | pm_runtime_get_sync(dev); |
21d5c57b | 851 | pm_runtime_clean_up_links(dev); |
5e928f77 | 852 | |
1901fb26 | 853 | driver_sysfs_remove(dev); |
0d3e5a2e | 854 | |
116af378 | 855 | if (dev->bus) |
c6f7e72a | 856 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
857 | BUS_NOTIFY_UNBIND_DRIVER, |
858 | dev); | |
859 | ||
baab52de | 860 | pm_runtime_put_sync(dev); |
e1866b33 | 861 | |
0f836ca4 | 862 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
863 | dev->bus->remove(dev); |
864 | else if (drv->remove) | |
0d3e5a2e | 865 | drv->remove(dev); |
876dcb5f AW |
866 | /* |
867 | * A concurrent invocation of the same function might | |
868 | * have released the driver successfully while this one | |
869 | * was waiting, so check for that. | |
5c727d0a AW |
870 | * LP: #1792099 |
871 | * | |
872 | * Limit this to the vfio_pci_driver as some drivers NULL | |
873 | * out this pointer in their remove() function. | |
874 | * LP: #1803942 | |
876dcb5f | 875 | */ |
5c727d0a | 876 | if (drv == vfio_pci_driver_ptr && dev->driver != drv) |
876dcb5f | 877 | return; |
9ed98953 RW |
878 | |
879 | device_links_driver_cleanup(dev); | |
09515ef5 S |
880 | dma_deconfigure(dev); |
881 | ||
9ac7849e | 882 | devres_release_all(dev); |
0d3e5a2e | 883 | dev->driver = NULL; |
0998d063 | 884 | dev_set_drvdata(dev, NULL); |
e90d5532 RW |
885 | if (dev->pm_domain && dev->pm_domain->dismiss) |
886 | dev->pm_domain->dismiss(dev); | |
5de85b9d | 887 | pm_runtime_reinit(dev); |
08810a41 | 888 | dev_pm_set_driver_flags(dev, 0); |
e90d5532 | 889 | |
8940b4f3 | 890 | klist_remove(&dev->p->knode_driver); |
aa8e54b5 | 891 | device_pm_check_callbacks(dev); |
309b7d60 JR |
892 | if (dev->bus) |
893 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
894 | BUS_NOTIFY_UNBOUND_DRIVER, | |
895 | dev); | |
1455cf8d DT |
896 | |
897 | kobject_uevent(&dev->kobj, KOBJ_UNBIND); | |
0d3e5a2e | 898 | } |
07e4a3e2 PM |
899 | } |
900 | ||
9ed98953 RW |
901 | void device_release_driver_internal(struct device *dev, |
902 | struct device_driver *drv, | |
903 | struct device *parent) | |
4bdb3550 RW |
904 | { |
905 | if (parent) | |
906 | device_lock(parent); | |
907 | ||
908 | device_lock(dev); | |
909 | if (!drv || drv == dev->driver) | |
9ed98953 | 910 | __device_release_driver(dev, parent); |
4bdb3550 RW |
911 | |
912 | device_unlock(dev); | |
913 | if (parent) | |
914 | device_unlock(parent); | |
915 | } | |
916 | ||
ab71c6f0 | 917 | /** |
4a3ad20c GKH |
918 | * device_release_driver - manually detach device from driver. |
919 | * @dev: device. | |
ab71c6f0 | 920 | * |
4a3ad20c | 921 | * Manually detach device from driver. |
8e9394ce | 922 | * When called for a USB interface, @dev->parent lock must be held. |
9ed98953 RW |
923 | * |
924 | * If this function is to be called with @dev->parent lock held, ensure that | |
925 | * the device's consumers are unbound in advance or that their locks can be | |
926 | * acquired under the @dev->parent lock. | |
ab71c6f0 | 927 | */ |
4a3ad20c | 928 | void device_release_driver(struct device *dev) |
94e7b1c5 | 929 | { |
c95a6b05 AS |
930 | /* |
931 | * If anyone calls device_release_driver() recursively from | |
932 | * within their ->remove callback for the same device, they | |
933 | * will deadlock right here. | |
934 | */ | |
4bdb3550 | 935 | device_release_driver_internal(dev, NULL, NULL); |
94e7b1c5 | 936 | } |
4a3ad20c | 937 | EXPORT_SYMBOL_GPL(device_release_driver); |
c95a6b05 | 938 | |
07e4a3e2 PM |
939 | /** |
940 | * driver_detach - detach driver from all devices it controls. | |
941 | * @drv: driver. | |
942 | */ | |
4a3ad20c | 943 | void driver_detach(struct device_driver *drv) |
07e4a3e2 | 944 | { |
8940b4f3 | 945 | struct device_private *dev_prv; |
4a3ad20c | 946 | struct device *dev; |
c95a6b05 AS |
947 | |
948 | for (;;) { | |
e5dd1278 GKH |
949 | spin_lock(&drv->p->klist_devices.k_lock); |
950 | if (list_empty(&drv->p->klist_devices.k_list)) { | |
951 | spin_unlock(&drv->p->klist_devices.k_lock); | |
c95a6b05 AS |
952 | break; |
953 | } | |
8940b4f3 GKH |
954 | dev_prv = list_entry(drv->p->klist_devices.k_list.prev, |
955 | struct device_private, | |
956 | knode_driver.n_node); | |
957 | dev = dev_prv->device; | |
c95a6b05 | 958 | get_device(dev); |
e5dd1278 | 959 | spin_unlock(&drv->p->klist_devices.k_lock); |
4bdb3550 | 960 | device_release_driver_internal(dev, drv, dev->parent); |
c95a6b05 AS |
961 | put_device(dev); |
962 | } | |
07e4a3e2 | 963 | } |