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Commit | Line | Data |
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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 GKH |
97 | struct stupid_thread_structure { |
98 | struct device_driver *drv; | |
99 | struct device *dev; | |
100 | }; | |
101 | ||
102 | static atomic_t probe_count = ATOMIC_INIT(0); | |
735a7ffb AM |
103 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
104 | ||
d779249e | 105 | static int really_probe(void *void_data) |
07e4a3e2 | 106 | { |
d779249e GKH |
107 | struct stupid_thread_structure *data = void_data; |
108 | struct device_driver *drv = data->drv; | |
109 | struct device *dev = data->dev; | |
0d3e5a2e | 110 | int ret = 0; |
07e4a3e2 | 111 | |
d779249e GKH |
112 | atomic_inc(&probe_count); |
113 | pr_debug("%s: Probing driver %s with device %s\n", | |
114 | drv->bus->name, drv->name, dev->bus_id); | |
07e4a3e2 | 115 | |
07e4a3e2 | 116 | dev->driver = drv; |
1901fb26 KS |
117 | if (driver_sysfs_add(dev)) { |
118 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
119 | __FUNCTION__, dev->bus_id); | |
120 | goto probe_failed; | |
121 | } | |
122 | ||
594c8281 RK |
123 | if (dev->bus->probe) { |
124 | ret = dev->bus->probe(dev); | |
1901fb26 | 125 | if (ret) |
d779249e | 126 | goto probe_failed; |
594c8281 | 127 | } else if (drv->probe) { |
0d3e5a2e | 128 | ret = drv->probe(dev); |
1901fb26 | 129 | if (ret) |
d779249e | 130 | goto probe_failed; |
f86db396 | 131 | } |
1901fb26 KS |
132 | |
133 | driver_bound(dev); | |
0d3e5a2e PM |
134 | ret = 1; |
135 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
136 | drv->bus->name, dev->bus_id, drv->name); | |
d779249e | 137 | goto done; |
0d3e5a2e | 138 | |
d779249e | 139 | probe_failed: |
1901fb26 KS |
140 | driver_sysfs_remove(dev); |
141 | dev->driver = NULL; | |
142 | ||
c578abbc | 143 | if (ret != -ENODEV && ret != -ENXIO) { |
0d3e5a2e PM |
144 | /* driver matched but the probe failed */ |
145 | printk(KERN_WARNING | |
146 | "%s: probe of %s failed with error %d\n", | |
147 | drv->name, dev->bus_id, ret); | |
148 | } | |
c578abbc CH |
149 | /* |
150 | * Ignore errors returned by ->probe so that the next driver can try | |
151 | * its luck. | |
152 | */ | |
153 | ret = 0; | |
d779249e GKH |
154 | done: |
155 | kfree(data); | |
156 | atomic_dec(&probe_count); | |
735a7ffb | 157 | wake_up(&probe_waitqueue); |
d779249e GKH |
158 | return ret; |
159 | } | |
160 | ||
161 | /** | |
162 | * driver_probe_done | |
163 | * Determine if the probe sequence is finished or not. | |
164 | * | |
165 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
166 | */ | |
167 | int driver_probe_done(void) | |
168 | { | |
169 | pr_debug("%s: probe_count = %d\n", __FUNCTION__, | |
170 | atomic_read(&probe_count)); | |
171 | if (atomic_read(&probe_count)) | |
172 | return -EBUSY; | |
173 | return 0; | |
174 | } | |
175 | ||
176 | /** | |
177 | * driver_probe_device - attempt to bind device & driver together | |
178 | * @drv: driver to bind a device to | |
179 | * @dev: device to try to bind to the driver | |
180 | * | |
181 | * First, we call the bus's match function, if one present, which should | |
182 | * compare the device IDs the driver supports with the device IDs of the | |
183 | * device. Note we don't do this ourselves because we don't know the | |
184 | * format of the ID structures, nor what is to be considered a match and | |
185 | * what is not. | |
186 | * | |
187 | * This function returns 1 if a match is found, an error if one occurs | |
188 | * (that is not -ENODEV or -ENXIO), and 0 otherwise. | |
189 | * | |
190 | * This function must be called with @dev->sem held. When called for a | |
191 | * USB interface, @dev->parent->sem must be held as well. | |
192 | */ | |
193 | int driver_probe_device(struct device_driver * drv, struct device * dev) | |
194 | { | |
195 | struct stupid_thread_structure *data; | |
196 | struct task_struct *probe_task; | |
197 | int ret = 0; | |
198 | ||
f2eaae19 AS |
199 | if (!device_is_registered(dev)) |
200 | return -ENODEV; | |
d779249e GKH |
201 | if (drv->bus->match && !drv->bus->match(dev, drv)) |
202 | goto done; | |
203 | ||
204 | pr_debug("%s: Matched Device %s with Driver %s\n", | |
205 | drv->bus->name, dev->bus_id, drv->name); | |
206 | ||
207 | data = kmalloc(sizeof(*data), GFP_KERNEL); | |
4d664238 AM |
208 | if (!data) |
209 | return -ENOMEM; | |
d779249e GKH |
210 | data->drv = drv; |
211 | data->dev = dev; | |
212 | ||
213 | if (drv->multithread_probe) { | |
214 | probe_task = kthread_run(really_probe, data, | |
215 | "probe-%s", dev->bus_id); | |
216 | if (IS_ERR(probe_task)) | |
0fbf116d | 217 | ret = really_probe(data); |
d779249e GKH |
218 | } else |
219 | ret = really_probe(data); | |
220 | ||
221 | done: | |
0d3e5a2e | 222 | return ret; |
07e4a3e2 PM |
223 | } |
224 | ||
2287c322 PM |
225 | static int __device_attach(struct device_driver * drv, void * data) |
226 | { | |
227 | struct device * dev = data; | |
0d3e5a2e | 228 | return driver_probe_device(drv, dev); |
2287c322 PM |
229 | } |
230 | ||
07e4a3e2 PM |
231 | /** |
232 | * device_attach - try to attach device to a driver. | |
233 | * @dev: device. | |
234 | * | |
235 | * Walk the list of drivers that the bus has and call | |
236 | * driver_probe_device() for each pair. If a compatible | |
237 | * pair is found, break out and return. | |
0d3e5a2e | 238 | * |
ca2b94ba HR |
239 | * Returns 1 if the device was bound to a driver; |
240 | * 0 if no matching device was found; error code otherwise. | |
bf74ad5b AS |
241 | * |
242 | * When called for a USB interface, @dev->parent->sem must be held. | |
07e4a3e2 PM |
243 | */ |
244 | int device_attach(struct device * dev) | |
245 | { | |
0d3e5a2e PM |
246 | int ret = 0; |
247 | ||
248 | down(&dev->sem); | |
07e4a3e2 | 249 | if (dev->driver) { |
f86db396 AM |
250 | ret = device_bind_driver(dev); |
251 | if (ret == 0) | |
252 | ret = 1; | |
0d3e5a2e PM |
253 | } else |
254 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
255 | up(&dev->sem); | |
256 | return ret; | |
2287c322 PM |
257 | } |
258 | ||
259 | static int __driver_attach(struct device * dev, void * data) | |
260 | { | |
261 | struct device_driver * drv = data; | |
0d3e5a2e PM |
262 | |
263 | /* | |
264 | * Lock device and try to bind to it. We drop the error | |
265 | * here and always return 0, because we need to keep trying | |
266 | * to bind to devices and some drivers will return an error | |
267 | * simply if it didn't support the device. | |
268 | * | |
269 | * driver_probe_device() will spit a warning if there | |
270 | * is an error. | |
271 | */ | |
272 | ||
bf74ad5b AS |
273 | if (dev->parent) /* Needed for USB */ |
274 | down(&dev->parent->sem); | |
0d3e5a2e PM |
275 | down(&dev->sem); |
276 | if (!dev->driver) | |
277 | driver_probe_device(drv, dev); | |
278 | up(&dev->sem); | |
bf74ad5b AS |
279 | if (dev->parent) |
280 | up(&dev->parent->sem); | |
0d3e5a2e | 281 | |
07e4a3e2 PM |
282 | return 0; |
283 | } | |
284 | ||
285 | /** | |
286 | * driver_attach - try to bind driver to devices. | |
287 | * @drv: driver. | |
288 | * | |
289 | * Walk the list of devices that the bus has on it and try to | |
290 | * match the driver with each one. If driver_probe_device() | |
291 | * returns 0 and the @dev->driver is set, we've found a | |
292 | * compatible pair. | |
07e4a3e2 | 293 | */ |
f86db396 | 294 | int driver_attach(struct device_driver * drv) |
07e4a3e2 | 295 | { |
f86db396 | 296 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 PM |
297 | } |
298 | ||
299 | /** | |
300 | * device_release_driver - manually detach device from driver. | |
301 | * @dev: device. | |
302 | * | |
303 | * Manually detach device from driver. | |
c95a6b05 AS |
304 | * |
305 | * __device_release_driver() must be called with @dev->sem held. | |
bf74ad5b AS |
306 | * When called for a USB interface, @dev->parent->sem must be held |
307 | * as well. | |
07e4a3e2 | 308 | */ |
c95a6b05 AS |
309 | |
310 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 311 | { |
0d3e5a2e | 312 | struct device_driver * drv; |
07e4a3e2 | 313 | |
c95a6b05 AS |
314 | drv = dev->driver; |
315 | if (drv) { | |
316 | get_driver(drv); | |
1901fb26 | 317 | driver_sysfs_remove(dev); |
0d3e5a2e | 318 | sysfs_remove_link(&dev->kobj, "driver"); |
c95a6b05 | 319 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 320 | |
116af378 BH |
321 | if (dev->bus) |
322 | blocking_notifier_call_chain(&dev->bus->bus_notifier, | |
323 | BUS_NOTIFY_UNBIND_DRIVER, | |
324 | dev); | |
325 | ||
0f836ca4 | 326 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
327 | dev->bus->remove(dev); |
328 | else if (drv->remove) | |
0d3e5a2e PM |
329 | drv->remove(dev); |
330 | dev->driver = NULL; | |
c95a6b05 | 331 | put_driver(drv); |
0d3e5a2e | 332 | } |
07e4a3e2 PM |
333 | } |
334 | ||
c95a6b05 | 335 | void device_release_driver(struct device * dev) |
94e7b1c5 | 336 | { |
c95a6b05 AS |
337 | /* |
338 | * If anyone calls device_release_driver() recursively from | |
339 | * within their ->remove callback for the same device, they | |
340 | * will deadlock right here. | |
341 | */ | |
342 | down(&dev->sem); | |
343 | __device_release_driver(dev); | |
344 | up(&dev->sem); | |
94e7b1c5 PM |
345 | } |
346 | ||
c95a6b05 | 347 | |
07e4a3e2 PM |
348 | /** |
349 | * driver_detach - detach driver from all devices it controls. | |
350 | * @drv: driver. | |
351 | */ | |
352 | void driver_detach(struct device_driver * drv) | |
353 | { | |
c95a6b05 AS |
354 | struct device * dev; |
355 | ||
356 | for (;;) { | |
2b08c8d0 | 357 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 358 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 359 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
360 | break; |
361 | } | |
362 | dev = list_entry(drv->klist_devices.k_list.prev, | |
363 | struct device, knode_driver.n_node); | |
364 | get_device(dev); | |
2b08c8d0 | 365 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 | 366 | |
bf74ad5b AS |
367 | if (dev->parent) /* Needed for USB */ |
368 | down(&dev->parent->sem); | |
c95a6b05 AS |
369 | down(&dev->sem); |
370 | if (dev->driver == drv) | |
371 | __device_release_driver(dev); | |
372 | up(&dev->sem); | |
bf74ad5b AS |
373 | if (dev->parent) |
374 | up(&dev->parent->sem); | |
c95a6b05 AS |
375 | put_device(dev); |
376 | } | |
07e4a3e2 PM |
377 | } |
378 | ||
735a7ffb AM |
379 | #ifdef CONFIG_PCI_MULTITHREAD_PROBE |
380 | static int __init wait_for_probes(void) | |
381 | { | |
382 | DEFINE_WAIT(wait); | |
383 | ||
384 | printk(KERN_INFO "%s: waiting for %d threads\n", __FUNCTION__, | |
385 | atomic_read(&probe_count)); | |
386 | if (!atomic_read(&probe_count)) | |
387 | return 0; | |
388 | while (atomic_read(&probe_count)) { | |
389 | prepare_to_wait(&probe_waitqueue, &wait, TASK_UNINTERRUPTIBLE); | |
390 | if (atomic_read(&probe_count)) | |
391 | schedule(); | |
392 | } | |
393 | finish_wait(&probe_waitqueue, &wait); | |
394 | return 0; | |
395 | } | |
396 | ||
397 | core_initcall_sync(wait_for_probes); | |
398 | postcore_initcall_sync(wait_for_probes); | |
399 | arch_initcall_sync(wait_for_probes); | |
400 | subsys_initcall_sync(wait_for_probes); | |
401 | fs_initcall_sync(wait_for_probes); | |
402 | device_initcall_sync(wait_for_probes); | |
403 | late_initcall_sync(wait_for_probes); | |
404 | #endif | |
07e4a3e2 | 405 | |
07e4a3e2 PM |
406 | EXPORT_SYMBOL_GPL(device_bind_driver); |
407 | EXPORT_SYMBOL_GPL(device_release_driver); | |
408 | EXPORT_SYMBOL_GPL(device_attach); | |
409 | EXPORT_SYMBOL_GPL(driver_attach); | |
410 |