]>
Commit | Line | Data |
---|---|---|
07e4a3e2 PM |
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 | * | |
15 | * This file is released under the GPLv2 | |
16 | */ | |
17 | ||
18 | #include <linux/device.h> | |
19 | #include <linux/module.h> | |
d779249e | 20 | #include <linux/kthread.h> |
735a7ffb | 21 | #include <linux/wait.h> |
07e4a3e2 PM |
22 | |
23 | #include "base.h" | |
24 | #include "power/power.h" | |
25 | ||
26 | #define to_drv(node) container_of(node, struct device_driver, kobj.entry) | |
27 | ||
28 | ||
1901fb26 | 29 | static void driver_bound(struct device *dev) |
07e4a3e2 | 30 | { |
f86db396 AM |
31 | if (klist_node_attached(&dev->knode_driver)) { |
32 | printk(KERN_WARNING "%s: device %s already bound\n", | |
33 | __FUNCTION__, kobject_name(&dev->kobj)); | |
1901fb26 | 34 | return; |
f86db396 | 35 | } |
4c898c7f | 36 | |
07e4a3e2 PM |
37 | pr_debug("bound device '%s' to driver '%s'\n", |
38 | dev->bus_id, dev->driver->name); | |
116af378 BH |
39 | |
40 | if (dev->bus) | |
41 | blocking_notifier_call_chain(&dev->bus->bus_notifier, | |
42 | BUS_NOTIFY_BOUND_DRIVER, dev); | |
43 | ||
d856f1e3 | 44 | klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); |
1901fb26 KS |
45 | } |
46 | ||
47 | static int driver_sysfs_add(struct device *dev) | |
48 | { | |
49 | int ret; | |
50 | ||
f86db396 | 51 | ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
07e4a3e2 | 52 | kobject_name(&dev->kobj)); |
f86db396 AM |
53 | if (ret == 0) { |
54 | ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj, | |
55 | "driver"); | |
56 | if (ret) | |
57 | sysfs_remove_link(&dev->driver->kobj, | |
58 | kobject_name(&dev->kobj)); | |
59 | } | |
60 | return ret; | |
07e4a3e2 PM |
61 | } |
62 | ||
1901fb26 KS |
63 | static void driver_sysfs_remove(struct device *dev) |
64 | { | |
65 | struct device_driver *drv = dev->driver; | |
66 | ||
67 | if (drv) { | |
68 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); | |
69 | sysfs_remove_link(&dev->kobj, "driver"); | |
70 | } | |
71 | } | |
72 | ||
73 | /** | |
74 | * device_bind_driver - bind a driver to one device. | |
75 | * @dev: device. | |
76 | * | |
77 | * Allow manual attachment of a driver to a device. | |
78 | * Caller must have already set @dev->driver. | |
79 | * | |
80 | * Note that this does not modify the bus reference count | |
81 | * nor take the bus's rwsem. Please verify those are accounted | |
82 | * for before calling this. (It is ok to call with no other effort | |
83 | * from a driver's probe() method.) | |
84 | * | |
85 | * This function must be called with @dev->sem held. | |
86 | */ | |
87 | int device_bind_driver(struct device *dev) | |
88 | { | |
cb986b74 CH |
89 | int ret; |
90 | ||
91 | ret = driver_sysfs_add(dev); | |
92 | if (!ret) | |
93 | driver_bound(dev); | |
94 | return ret; | |
1901fb26 KS |
95 | } |
96 | ||
d779249e | 97 | static atomic_t probe_count = ATOMIC_INIT(0); |
735a7ffb AM |
98 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
99 | ||
21c7f30b | 100 | static int really_probe(struct device *dev, struct device_driver *drv) |
07e4a3e2 | 101 | { |
0d3e5a2e | 102 | int ret = 0; |
07e4a3e2 | 103 | |
d779249e GKH |
104 | atomic_inc(&probe_count); |
105 | pr_debug("%s: Probing driver %s with device %s\n", | |
106 | drv->bus->name, drv->name, dev->bus_id); | |
9ac7849e | 107 | WARN_ON(!list_empty(&dev->devres_head)); |
07e4a3e2 | 108 | |
07e4a3e2 | 109 | dev->driver = drv; |
1901fb26 KS |
110 | if (driver_sysfs_add(dev)) { |
111 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
112 | __FUNCTION__, dev->bus_id); | |
113 | goto probe_failed; | |
114 | } | |
115 | ||
594c8281 RK |
116 | if (dev->bus->probe) { |
117 | ret = dev->bus->probe(dev); | |
1901fb26 | 118 | if (ret) |
d779249e | 119 | goto probe_failed; |
594c8281 | 120 | } else if (drv->probe) { |
0d3e5a2e | 121 | ret = drv->probe(dev); |
1901fb26 | 122 | if (ret) |
d779249e | 123 | goto probe_failed; |
f86db396 | 124 | } |
1901fb26 KS |
125 | |
126 | driver_bound(dev); | |
0d3e5a2e PM |
127 | ret = 1; |
128 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
129 | drv->bus->name, dev->bus_id, drv->name); | |
d779249e | 130 | goto done; |
0d3e5a2e | 131 | |
d779249e | 132 | probe_failed: |
9ac7849e | 133 | devres_release_all(dev); |
1901fb26 KS |
134 | driver_sysfs_remove(dev); |
135 | dev->driver = NULL; | |
136 | ||
c578abbc | 137 | if (ret != -ENODEV && ret != -ENXIO) { |
0d3e5a2e PM |
138 | /* driver matched but the probe failed */ |
139 | printk(KERN_WARNING | |
140 | "%s: probe of %s failed with error %d\n", | |
141 | drv->name, dev->bus_id, ret); | |
142 | } | |
c578abbc CH |
143 | /* |
144 | * Ignore errors returned by ->probe so that the next driver can try | |
145 | * its luck. | |
146 | */ | |
147 | ret = 0; | |
d779249e | 148 | done: |
d779249e | 149 | atomic_dec(&probe_count); |
735a7ffb | 150 | wake_up(&probe_waitqueue); |
d779249e GKH |
151 | return ret; |
152 | } | |
153 | ||
154 | /** | |
155 | * driver_probe_done | |
156 | * Determine if the probe sequence is finished or not. | |
157 | * | |
158 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
159 | */ | |
160 | int driver_probe_done(void) | |
161 | { | |
162 | pr_debug("%s: probe_count = %d\n", __FUNCTION__, | |
163 | atomic_read(&probe_count)); | |
164 | if (atomic_read(&probe_count)) | |
165 | return -EBUSY; | |
166 | return 0; | |
167 | } | |
168 | ||
169 | /** | |
170 | * driver_probe_device - attempt to bind device & driver together | |
171 | * @drv: driver to bind a device to | |
172 | * @dev: device to try to bind to the driver | |
173 | * | |
174 | * First, we call the bus's match function, if one present, which should | |
175 | * compare the device IDs the driver supports with the device IDs of the | |
176 | * device. Note we don't do this ourselves because we don't know the | |
177 | * format of the ID structures, nor what is to be considered a match and | |
178 | * what is not. | |
179 | * | |
21c7f30b CH |
180 | * This function returns 1 if a match is found, -ENODEV if the device is |
181 | * not registered, and 0 otherwise. | |
d779249e GKH |
182 | * |
183 | * This function must be called with @dev->sem held. When called for a | |
184 | * USB interface, @dev->parent->sem must be held as well. | |
185 | */ | |
186 | int driver_probe_device(struct device_driver * drv, struct device * dev) | |
187 | { | |
d779249e GKH |
188 | int ret = 0; |
189 | ||
f2eaae19 AS |
190 | if (!device_is_registered(dev)) |
191 | return -ENODEV; | |
d779249e GKH |
192 | if (drv->bus->match && !drv->bus->match(dev, drv)) |
193 | goto done; | |
194 | ||
195 | pr_debug("%s: Matched Device %s with Driver %s\n", | |
196 | drv->bus->name, dev->bus_id, drv->name); | |
197 | ||
21c7f30b | 198 | ret = really_probe(dev, drv); |
d779249e GKH |
199 | |
200 | done: | |
0d3e5a2e | 201 | return ret; |
07e4a3e2 PM |
202 | } |
203 | ||
2287c322 PM |
204 | static int __device_attach(struct device_driver * drv, void * data) |
205 | { | |
206 | struct device * dev = data; | |
0d3e5a2e | 207 | return driver_probe_device(drv, dev); |
2287c322 PM |
208 | } |
209 | ||
21c7f30b CH |
210 | static int device_probe_drivers(void *data) |
211 | { | |
212 | struct device *dev = data; | |
213 | int ret = 0; | |
214 | ||
215 | if (dev->bus) { | |
216 | down(&dev->sem); | |
217 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
218 | up(&dev->sem); | |
219 | } | |
220 | return ret; | |
221 | } | |
222 | ||
07e4a3e2 PM |
223 | /** |
224 | * device_attach - try to attach device to a driver. | |
225 | * @dev: device. | |
226 | * | |
227 | * Walk the list of drivers that the bus has and call | |
228 | * driver_probe_device() for each pair. If a compatible | |
21c7f30b CH |
229 | * pair is found, break out and return. If the bus specifies |
230 | * multithreaded probing, walking the list of drivers is done | |
231 | * on a probing thread. | |
0d3e5a2e | 232 | * |
ca2b94ba | 233 | * Returns 1 if the device was bound to a driver; |
21c7f30b CH |
234 | * 0 if no matching device was found or multithreaded probing is done; |
235 | * error code otherwise. | |
bf74ad5b AS |
236 | * |
237 | * When called for a USB interface, @dev->parent->sem must be held. | |
07e4a3e2 PM |
238 | */ |
239 | int device_attach(struct device * dev) | |
240 | { | |
0d3e5a2e | 241 | int ret = 0; |
21c7f30b | 242 | struct task_struct *probe_task = ERR_PTR(-ENOMEM); |
0d3e5a2e PM |
243 | |
244 | down(&dev->sem); | |
07e4a3e2 | 245 | if (dev->driver) { |
f86db396 AM |
246 | ret = device_bind_driver(dev); |
247 | if (ret == 0) | |
248 | ret = 1; | |
21c7f30b CH |
249 | } else { |
250 | if (dev->bus->multithread_probe) | |
251 | probe_task = kthread_run(device_probe_drivers, dev, | |
252 | "probe-%s", dev->bus_id); | |
253 | if(IS_ERR(probe_task)) | |
254 | ret = bus_for_each_drv(dev->bus, NULL, dev, | |
255 | __device_attach); | |
256 | } | |
0d3e5a2e PM |
257 | up(&dev->sem); |
258 | return ret; | |
2287c322 PM |
259 | } |
260 | ||
261 | static int __driver_attach(struct device * dev, void * data) | |
262 | { | |
263 | struct device_driver * drv = data; | |
0d3e5a2e PM |
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 | ||
bf74ad5b AS |
275 | if (dev->parent) /* Needed for USB */ |
276 | down(&dev->parent->sem); | |
0d3e5a2e PM |
277 | down(&dev->sem); |
278 | if (!dev->driver) | |
279 | driver_probe_device(drv, dev); | |
280 | up(&dev->sem); | |
bf74ad5b AS |
281 | if (dev->parent) |
282 | up(&dev->parent->sem); | |
0d3e5a2e | 283 | |
07e4a3e2 PM |
284 | return 0; |
285 | } | |
286 | ||
287 | /** | |
288 | * driver_attach - try to bind driver to devices. | |
289 | * @drv: driver. | |
290 | * | |
291 | * Walk the list of devices that the bus has on it and try to | |
292 | * match the driver with each one. If driver_probe_device() | |
293 | * returns 0 and the @dev->driver is set, we've found a | |
294 | * compatible pair. | |
07e4a3e2 | 295 | */ |
f86db396 | 296 | int driver_attach(struct device_driver * drv) |
07e4a3e2 | 297 | { |
f86db396 | 298 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 PM |
299 | } |
300 | ||
301 | /** | |
302 | * device_release_driver - manually detach device from driver. | |
303 | * @dev: device. | |
304 | * | |
305 | * Manually detach device from driver. | |
c95a6b05 AS |
306 | * |
307 | * __device_release_driver() must be called with @dev->sem held. | |
bf74ad5b AS |
308 | * When called for a USB interface, @dev->parent->sem must be held |
309 | * as well. | |
07e4a3e2 | 310 | */ |
c95a6b05 AS |
311 | |
312 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 313 | { |
0d3e5a2e | 314 | struct device_driver * drv; |
07e4a3e2 | 315 | |
c95a6b05 AS |
316 | drv = dev->driver; |
317 | if (drv) { | |
318 | get_driver(drv); | |
1901fb26 | 319 | driver_sysfs_remove(dev); |
0d3e5a2e | 320 | sysfs_remove_link(&dev->kobj, "driver"); |
c95a6b05 | 321 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 322 | |
116af378 BH |
323 | if (dev->bus) |
324 | blocking_notifier_call_chain(&dev->bus->bus_notifier, | |
325 | BUS_NOTIFY_UNBIND_DRIVER, | |
326 | dev); | |
327 | ||
0f836ca4 | 328 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
329 | dev->bus->remove(dev); |
330 | else if (drv->remove) | |
0d3e5a2e | 331 | drv->remove(dev); |
9ac7849e | 332 | devres_release_all(dev); |
0d3e5a2e | 333 | dev->driver = NULL; |
c95a6b05 | 334 | put_driver(drv); |
0d3e5a2e | 335 | } |
07e4a3e2 PM |
336 | } |
337 | ||
c95a6b05 | 338 | void device_release_driver(struct device * dev) |
94e7b1c5 | 339 | { |
c95a6b05 AS |
340 | /* |
341 | * If anyone calls device_release_driver() recursively from | |
342 | * within their ->remove callback for the same device, they | |
343 | * will deadlock right here. | |
344 | */ | |
345 | down(&dev->sem); | |
346 | __device_release_driver(dev); | |
347 | up(&dev->sem); | |
94e7b1c5 PM |
348 | } |
349 | ||
c95a6b05 | 350 | |
07e4a3e2 PM |
351 | /** |
352 | * driver_detach - detach driver from all devices it controls. | |
353 | * @drv: driver. | |
354 | */ | |
355 | void driver_detach(struct device_driver * drv) | |
356 | { | |
c95a6b05 AS |
357 | struct device * dev; |
358 | ||
359 | for (;;) { | |
2b08c8d0 | 360 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 361 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 362 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
363 | break; |
364 | } | |
365 | dev = list_entry(drv->klist_devices.k_list.prev, | |
366 | struct device, knode_driver.n_node); | |
367 | get_device(dev); | |
2b08c8d0 | 368 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 | 369 | |
bf74ad5b AS |
370 | if (dev->parent) /* Needed for USB */ |
371 | down(&dev->parent->sem); | |
c95a6b05 AS |
372 | down(&dev->sem); |
373 | if (dev->driver == drv) | |
374 | __device_release_driver(dev); | |
375 | up(&dev->sem); | |
bf74ad5b AS |
376 | if (dev->parent) |
377 | up(&dev->parent->sem); | |
c95a6b05 AS |
378 | put_device(dev); |
379 | } | |
07e4a3e2 PM |
380 | } |
381 | ||
735a7ffb AM |
382 | #ifdef CONFIG_PCI_MULTITHREAD_PROBE |
383 | static int __init wait_for_probes(void) | |
384 | { | |
385 | DEFINE_WAIT(wait); | |
386 | ||
387 | printk(KERN_INFO "%s: waiting for %d threads\n", __FUNCTION__, | |
388 | atomic_read(&probe_count)); | |
389 | if (!atomic_read(&probe_count)) | |
390 | return 0; | |
391 | while (atomic_read(&probe_count)) { | |
392 | prepare_to_wait(&probe_waitqueue, &wait, TASK_UNINTERRUPTIBLE); | |
393 | if (atomic_read(&probe_count)) | |
394 | schedule(); | |
395 | } | |
396 | finish_wait(&probe_waitqueue, &wait); | |
397 | return 0; | |
398 | } | |
399 | ||
400 | core_initcall_sync(wait_for_probes); | |
401 | postcore_initcall_sync(wait_for_probes); | |
402 | arch_initcall_sync(wait_for_probes); | |
403 | subsys_initcall_sync(wait_for_probes); | |
404 | fs_initcall_sync(wait_for_probes); | |
405 | device_initcall_sync(wait_for_probes); | |
406 | late_initcall_sync(wait_for_probes); | |
407 | #endif | |
07e4a3e2 | 408 | |
07e4a3e2 PM |
409 | EXPORT_SYMBOL_GPL(device_bind_driver); |
410 | EXPORT_SYMBOL_GPL(device_release_driver); | |
411 | EXPORT_SYMBOL_GPL(device_attach); | |
412 | EXPORT_SYMBOL_GPL(driver_attach); | |
413 |