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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 | ||
28 | #include "base.h" | |
29 | #include "power/power.h" | |
30 | ||
31 | ||
32 | static void driver_bound(struct device *dev) | |
33 | { | |
34 | if (klist_node_attached(&dev->p->knode_driver)) { | |
35 | printk(KERN_WARNING "%s: device %s already bound\n", | |
36 | __func__, kobject_name(&dev->kobj)); | |
37 | return; | |
38 | } | |
39 | ||
40 | pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev), | |
41 | __func__, dev->driver->name); | |
42 | ||
43 | if (dev->bus) | |
44 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
45 | BUS_NOTIFY_BOUND_DRIVER, dev); | |
46 | ||
47 | klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); | |
48 | } | |
49 | ||
50 | static int driver_sysfs_add(struct device *dev) | |
51 | { | |
52 | int ret; | |
53 | ||
54 | ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, | |
55 | kobject_name(&dev->kobj)); | |
56 | if (ret == 0) { | |
57 | ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, | |
58 | "driver"); | |
59 | if (ret) | |
60 | sysfs_remove_link(&dev->driver->p->kobj, | |
61 | kobject_name(&dev->kobj)); | |
62 | } | |
63 | return ret; | |
64 | } | |
65 | ||
66 | static void driver_sysfs_remove(struct device *dev) | |
67 | { | |
68 | struct device_driver *drv = dev->driver; | |
69 | ||
70 | if (drv) { | |
71 | sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); | |
72 | sysfs_remove_link(&dev->kobj, "driver"); | |
73 | } | |
74 | } | |
75 | ||
76 | /** | |
77 | * device_bind_driver - bind a driver to one device. | |
78 | * @dev: device. | |
79 | * | |
80 | * Allow manual attachment of a driver to a device. | |
81 | * Caller must have already set @dev->driver. | |
82 | * | |
83 | * Note that this does not modify the bus reference count | |
84 | * nor take the bus's rwsem. Please verify those are accounted | |
85 | * for before calling this. (It is ok to call with no other effort | |
86 | * from a driver's probe() method.) | |
87 | * | |
88 | * This function must be called with @dev->sem held. | |
89 | */ | |
90 | int device_bind_driver(struct device *dev) | |
91 | { | |
92 | int ret; | |
93 | ||
94 | ret = driver_sysfs_add(dev); | |
95 | if (!ret) | |
96 | driver_bound(dev); | |
97 | return ret; | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(device_bind_driver); | |
100 | ||
101 | static atomic_t probe_count = ATOMIC_INIT(0); | |
102 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); | |
103 | ||
104 | static int really_probe(struct device *dev, struct device_driver *drv) | |
105 | { | |
106 | int ret = 0; | |
107 | ||
108 | atomic_inc(&probe_count); | |
109 | pr_debug("bus: '%s': %s: probing driver %s with device %s\n", | |
110 | drv->bus->name, __func__, drv->name, dev_name(dev)); | |
111 | WARN_ON(!list_empty(&dev->devres_head)); | |
112 | ||
113 | dev->driver = drv; | |
114 | if (driver_sysfs_add(dev)) { | |
115 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
116 | __func__, dev_name(dev)); | |
117 | goto probe_failed; | |
118 | } | |
119 | ||
120 | if (dev->bus->probe) { | |
121 | ret = dev->bus->probe(dev); | |
122 | if (ret) | |
123 | goto probe_failed; | |
124 | } else if (drv->probe) { | |
125 | ret = drv->probe(dev); | |
126 | if (ret) | |
127 | goto probe_failed; | |
128 | } | |
129 | ||
130 | driver_bound(dev); | |
131 | ret = 1; | |
132 | pr_debug("bus: '%s': %s: bound device %s to driver %s\n", | |
133 | drv->bus->name, __func__, dev_name(dev), drv->name); | |
134 | goto done; | |
135 | ||
136 | probe_failed: | |
137 | devres_release_all(dev); | |
138 | driver_sysfs_remove(dev); | |
139 | dev->driver = NULL; | |
140 | ||
141 | if (ret != -ENODEV && ret != -ENXIO) { | |
142 | /* driver matched but the probe failed */ | |
143 | printk(KERN_WARNING | |
144 | "%s: probe of %s failed with error %d\n", | |
145 | drv->name, dev_name(dev), ret); | |
146 | } | |
147 | /* | |
148 | * Ignore errors returned by ->probe so that the next driver can try | |
149 | * its luck. | |
150 | */ | |
151 | ret = 0; | |
152 | done: | |
153 | atomic_dec(&probe_count); | |
154 | wake_up(&probe_waitqueue); | |
155 | return ret; | |
156 | } | |
157 | ||
158 | /** | |
159 | * driver_probe_done | |
160 | * Determine if the probe sequence is finished or not. | |
161 | * | |
162 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
163 | */ | |
164 | int driver_probe_done(void) | |
165 | { | |
166 | pr_debug("%s: probe_count = %d\n", __func__, | |
167 | atomic_read(&probe_count)); | |
168 | if (atomic_read(&probe_count)) | |
169 | return -EBUSY; | |
170 | return 0; | |
171 | } | |
172 | ||
173 | /** | |
174 | * wait_for_device_probe | |
175 | * Wait for device probing to be completed. | |
176 | */ | |
177 | void wait_for_device_probe(void) | |
178 | { | |
179 | /* wait for the known devices to complete their probing */ | |
180 | wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); | |
181 | async_synchronize_full(); | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(wait_for_device_probe); | |
184 | ||
185 | /** | |
186 | * driver_probe_device - attempt to bind device & driver together | |
187 | * @drv: driver to bind a device to | |
188 | * @dev: device to try to bind to the driver | |
189 | * | |
190 | * This function returns -ENODEV if the device is not registered, | |
191 | * 1 if the device is bound sucessfully and 0 otherwise. | |
192 | * | |
193 | * This function must be called with @dev->sem held. When called for a | |
194 | * USB interface, @dev->parent->sem must be held as well. | |
195 | */ | |
196 | int driver_probe_device(struct device_driver *drv, struct device *dev) | |
197 | { | |
198 | int ret = 0; | |
199 | ||
200 | if (!device_is_registered(dev)) | |
201 | return -ENODEV; | |
202 | ||
203 | pr_debug("bus: '%s': %s: matched device %s with driver %s\n", | |
204 | drv->bus->name, __func__, dev_name(dev), drv->name); | |
205 | ||
206 | pm_runtime_get_noresume(dev); | |
207 | pm_runtime_barrier(dev); | |
208 | ret = really_probe(dev, drv); | |
209 | pm_runtime_put_sync(dev); | |
210 | ||
211 | return ret; | |
212 | } | |
213 | ||
214 | static int __device_attach(struct device_driver *drv, void *data) | |
215 | { | |
216 | struct device *dev = data; | |
217 | ||
218 | if (!driver_match_device(drv, dev)) | |
219 | return 0; | |
220 | ||
221 | return driver_probe_device(drv, dev); | |
222 | } | |
223 | ||
224 | /** | |
225 | * device_attach - try to attach device to a driver. | |
226 | * @dev: device. | |
227 | * | |
228 | * Walk the list of drivers that the bus has and call | |
229 | * driver_probe_device() for each pair. If a compatible | |
230 | * pair is found, break out and return. | |
231 | * | |
232 | * Returns 1 if the device was bound to a driver; | |
233 | * 0 if no matching driver was found; | |
234 | * -ENODEV if the device is not registered. | |
235 | * | |
236 | * When called for a USB interface, @dev->parent->sem must be held. | |
237 | */ | |
238 | int device_attach(struct device *dev) | |
239 | { | |
240 | int ret = 0; | |
241 | ||
242 | down(&dev->sem); | |
243 | if (dev->driver) { | |
244 | ret = device_bind_driver(dev); | |
245 | if (ret == 0) | |
246 | ret = 1; | |
247 | else { | |
248 | dev->driver = NULL; | |
249 | ret = 0; | |
250 | } | |
251 | } else { | |
252 | pm_runtime_get_noresume(dev); | |
253 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
254 | pm_runtime_put_sync(dev); | |
255 | } | |
256 | up(&dev->sem); | |
257 | return ret; | |
258 | } | |
259 | EXPORT_SYMBOL_GPL(device_attach); | |
260 | ||
261 | static int __driver_attach(struct device *dev, void *data) | |
262 | { | |
263 | struct device_driver *drv = data; | |
264 | ||
265 | /* | |
266 | * Lock device and try to bind to it. We drop the error | |
267 | * here and always return 0, because we need to keep trying | |
268 | * to bind to devices and some drivers will return an error | |
269 | * simply if it didn't support the device. | |
270 | * | |
271 | * driver_probe_device() will spit a warning if there | |
272 | * is an error. | |
273 | */ | |
274 | ||
275 | if (!driver_match_device(drv, dev)) | |
276 | return 0; | |
277 | ||
278 | if (dev->parent) /* Needed for USB */ | |
279 | down(&dev->parent->sem); | |
280 | down(&dev->sem); | |
281 | if (!dev->driver) | |
282 | driver_probe_device(drv, dev); | |
283 | up(&dev->sem); | |
284 | if (dev->parent) | |
285 | up(&dev->parent->sem); | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
290 | /** | |
291 | * driver_attach - try to bind driver to devices. | |
292 | * @drv: driver. | |
293 | * | |
294 | * Walk the list of devices that the bus has on it and try to | |
295 | * match the driver with each one. If driver_probe_device() | |
296 | * returns 0 and the @dev->driver is set, we've found a | |
297 | * compatible pair. | |
298 | */ | |
299 | int driver_attach(struct device_driver *drv) | |
300 | { | |
301 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); | |
302 | } | |
303 | EXPORT_SYMBOL_GPL(driver_attach); | |
304 | ||
305 | /* | |
306 | * __device_release_driver() must be called with @dev->sem held. | |
307 | * When called for a USB interface, @dev->parent->sem must be held as well. | |
308 | */ | |
309 | static void __device_release_driver(struct device *dev) | |
310 | { | |
311 | struct device_driver *drv; | |
312 | ||
313 | drv = dev->driver; | |
314 | if (drv) { | |
315 | pm_runtime_get_noresume(dev); | |
316 | pm_runtime_barrier(dev); | |
317 | ||
318 | driver_sysfs_remove(dev); | |
319 | ||
320 | if (dev->bus) | |
321 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
322 | BUS_NOTIFY_UNBIND_DRIVER, | |
323 | dev); | |
324 | ||
325 | if (dev->bus && dev->bus->remove) | |
326 | dev->bus->remove(dev); | |
327 | else if (drv->remove) | |
328 | drv->remove(dev); | |
329 | devres_release_all(dev); | |
330 | dev->driver = NULL; | |
331 | klist_remove(&dev->p->knode_driver); | |
332 | if (dev->bus) | |
333 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, | |
334 | BUS_NOTIFY_UNBOUND_DRIVER, | |
335 | dev); | |
336 | ||
337 | pm_runtime_put_sync(dev); | |
338 | } | |
339 | } | |
340 | ||
341 | /** | |
342 | * device_release_driver - manually detach device from driver. | |
343 | * @dev: device. | |
344 | * | |
345 | * Manually detach device from driver. | |
346 | * When called for a USB interface, @dev->parent->sem must be held. | |
347 | */ | |
348 | void device_release_driver(struct device *dev) | |
349 | { | |
350 | /* | |
351 | * If anyone calls device_release_driver() recursively from | |
352 | * within their ->remove callback for the same device, they | |
353 | * will deadlock right here. | |
354 | */ | |
355 | down(&dev->sem); | |
356 | __device_release_driver(dev); | |
357 | up(&dev->sem); | |
358 | } | |
359 | EXPORT_SYMBOL_GPL(device_release_driver); | |
360 | ||
361 | /** | |
362 | * driver_detach - detach driver from all devices it controls. | |
363 | * @drv: driver. | |
364 | */ | |
365 | void driver_detach(struct device_driver *drv) | |
366 | { | |
367 | struct device_private *dev_prv; | |
368 | struct device *dev; | |
369 | ||
370 | for (;;) { | |
371 | spin_lock(&drv->p->klist_devices.k_lock); | |
372 | if (list_empty(&drv->p->klist_devices.k_list)) { | |
373 | spin_unlock(&drv->p->klist_devices.k_lock); | |
374 | break; | |
375 | } | |
376 | dev_prv = list_entry(drv->p->klist_devices.k_list.prev, | |
377 | struct device_private, | |
378 | knode_driver.n_node); | |
379 | dev = dev_prv->device; | |
380 | get_device(dev); | |
381 | spin_unlock(&drv->p->klist_devices.k_lock); | |
382 | ||
383 | if (dev->parent) /* Needed for USB */ | |
384 | down(&dev->parent->sem); | |
385 | down(&dev->sem); | |
386 | if (dev->driver == drv) | |
387 | __device_release_driver(dev); | |
388 | up(&dev->sem); | |
389 | if (dev->parent) | |
390 | up(&dev->parent->sem); | |
391 | put_device(dev); | |
392 | } | |
393 | } | |
394 | ||
395 | /* | |
396 | * These exports can't be _GPL due to .h files using this within them, and it | |
397 | * might break something that was previously working... | |
398 | */ | |
399 | void *dev_get_drvdata(const struct device *dev) | |
400 | { | |
401 | if (dev && dev->p) | |
402 | return dev->p->driver_data; | |
403 | return NULL; | |
404 | } | |
405 | EXPORT_SYMBOL(dev_get_drvdata); | |
406 | ||
407 | void dev_set_drvdata(struct device *dev, void *data) | |
408 | { | |
409 | int error; | |
410 | ||
411 | if (!dev) | |
412 | return; | |
413 | if (!dev->p) { | |
414 | error = device_private_init(dev); | |
415 | if (error) | |
416 | return; | |
417 | } | |
418 | dev->p->driver_data = data; | |
419 | } | |
420 | EXPORT_SYMBOL(dev_set_drvdata); |