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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 | |
14 | * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> | |
15 | * Copyright (c) 2007 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> |
07e4a3e2 | 22 | #include <linux/module.h> |
d779249e | 23 | #include <linux/kthread.h> |
735a7ffb | 24 | #include <linux/wait.h> |
216773a7 | 25 | #include <linux/async.h> |
07e4a3e2 PM |
26 | |
27 | #include "base.h" | |
28 | #include "power/power.h" | |
29 | ||
07e4a3e2 | 30 | |
1901fb26 | 31 | static void driver_bound(struct device *dev) |
07e4a3e2 | 32 | { |
cda5e83f | 33 | if (klist_node_attached(&dev->knode_driver)) { |
f86db396 | 34 | printk(KERN_WARNING "%s: device %s already bound\n", |
2b3a302a | 35 | __func__, kobject_name(&dev->kobj)); |
1901fb26 | 36 | return; |
f86db396 | 37 | } |
4c898c7f | 38 | |
1e0b2cf9 | 39 | pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev), |
2b3a302a | 40 | __func__, dev->driver->name); |
116af378 BH |
41 | |
42 | if (dev->bus) | |
c6f7e72a | 43 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
44 | BUS_NOTIFY_BOUND_DRIVER, dev); |
45 | ||
cda5e83f | 46 | klist_add_tail(&dev->knode_driver, &dev->driver->p->klist_devices); |
1901fb26 KS |
47 | } |
48 | ||
49 | static int driver_sysfs_add(struct device *dev) | |
50 | { | |
51 | int ret; | |
52 | ||
e5dd1278 | 53 | ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
07e4a3e2 | 54 | kobject_name(&dev->kobj)); |
f86db396 | 55 | if (ret == 0) { |
e5dd1278 | 56 | ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
f86db396 AM |
57 | "driver"); |
58 | if (ret) | |
e5dd1278 | 59 | sysfs_remove_link(&dev->driver->p->kobj, |
f86db396 AM |
60 | kobject_name(&dev->kobj)); |
61 | } | |
62 | return ret; | |
07e4a3e2 PM |
63 | } |
64 | ||
1901fb26 KS |
65 | static void driver_sysfs_remove(struct device *dev) |
66 | { | |
67 | struct device_driver *drv = dev->driver; | |
68 | ||
69 | if (drv) { | |
e5dd1278 | 70 | sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
1901fb26 KS |
71 | sysfs_remove_link(&dev->kobj, "driver"); |
72 | } | |
73 | } | |
74 | ||
75 | /** | |
4a3ad20c GKH |
76 | * device_bind_driver - bind a driver to one device. |
77 | * @dev: device. | |
1901fb26 | 78 | * |
4a3ad20c GKH |
79 | * Allow manual attachment of a driver to a device. |
80 | * Caller must have already set @dev->driver. | |
1901fb26 | 81 | * |
4a3ad20c GKH |
82 | * Note that this does not modify the bus reference count |
83 | * nor take the bus's rwsem. Please verify those are accounted | |
84 | * for before calling this. (It is ok to call with no other effort | |
85 | * from a driver's probe() method.) | |
1901fb26 | 86 | * |
4a3ad20c | 87 | * This function must be called with @dev->sem held. |
1901fb26 KS |
88 | */ |
89 | int device_bind_driver(struct device *dev) | |
90 | { | |
cb986b74 CH |
91 | int ret; |
92 | ||
93 | ret = driver_sysfs_add(dev); | |
94 | if (!ret) | |
95 | driver_bound(dev); | |
96 | return ret; | |
1901fb26 | 97 | } |
4a3ad20c | 98 | EXPORT_SYMBOL_GPL(device_bind_driver); |
1901fb26 | 99 | |
d779249e | 100 | static atomic_t probe_count = ATOMIC_INIT(0); |
735a7ffb AM |
101 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
102 | ||
21c7f30b | 103 | static int really_probe(struct device *dev, struct device_driver *drv) |
07e4a3e2 | 104 | { |
0d3e5a2e | 105 | int ret = 0; |
07e4a3e2 | 106 | |
d779249e | 107 | atomic_inc(&probe_count); |
7dc72b28 | 108 | pr_debug("bus: '%s': %s: probing driver %s with device %s\n", |
1e0b2cf9 | 109 | drv->bus->name, __func__, drv->name, dev_name(dev)); |
9ac7849e | 110 | WARN_ON(!list_empty(&dev->devres_head)); |
07e4a3e2 | 111 | |
07e4a3e2 | 112 | dev->driver = drv; |
1901fb26 KS |
113 | if (driver_sysfs_add(dev)) { |
114 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
1e0b2cf9 | 115 | __func__, dev_name(dev)); |
1901fb26 KS |
116 | goto probe_failed; |
117 | } | |
118 | ||
594c8281 RK |
119 | if (dev->bus->probe) { |
120 | ret = dev->bus->probe(dev); | |
1901fb26 | 121 | if (ret) |
d779249e | 122 | goto probe_failed; |
594c8281 | 123 | } else if (drv->probe) { |
0d3e5a2e | 124 | ret = drv->probe(dev); |
1901fb26 | 125 | if (ret) |
d779249e | 126 | goto probe_failed; |
f86db396 | 127 | } |
1901fb26 KS |
128 | |
129 | driver_bound(dev); | |
0d3e5a2e | 130 | ret = 1; |
7dc72b28 | 131 | pr_debug("bus: '%s': %s: bound device %s to driver %s\n", |
1e0b2cf9 | 132 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 133 | goto done; |
0d3e5a2e | 134 | |
d779249e | 135 | probe_failed: |
9ac7849e | 136 | devres_release_all(dev); |
1901fb26 KS |
137 | driver_sysfs_remove(dev); |
138 | dev->driver = NULL; | |
139 | ||
c578abbc | 140 | if (ret != -ENODEV && ret != -ENXIO) { |
0d3e5a2e PM |
141 | /* driver matched but the probe failed */ |
142 | printk(KERN_WARNING | |
143 | "%s: probe of %s failed with error %d\n", | |
1e0b2cf9 | 144 | drv->name, dev_name(dev), ret); |
0d3e5a2e | 145 | } |
c578abbc CH |
146 | /* |
147 | * Ignore errors returned by ->probe so that the next driver can try | |
148 | * its luck. | |
149 | */ | |
150 | ret = 0; | |
d779249e | 151 | done: |
d779249e | 152 | atomic_dec(&probe_count); |
735a7ffb | 153 | wake_up(&probe_waitqueue); |
d779249e GKH |
154 | return ret; |
155 | } | |
156 | ||
157 | /** | |
158 | * driver_probe_done | |
159 | * Determine if the probe sequence is finished or not. | |
160 | * | |
161 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
162 | */ | |
163 | int driver_probe_done(void) | |
164 | { | |
2b3a302a | 165 | pr_debug("%s: probe_count = %d\n", __func__, |
d779249e GKH |
166 | atomic_read(&probe_count)); |
167 | if (atomic_read(&probe_count)) | |
168 | return -EBUSY; | |
169 | return 0; | |
170 | } | |
171 | ||
216773a7 AV |
172 | /** |
173 | * wait_for_device_probe | |
174 | * Wait for device probing to be completed. | |
175 | * | |
176 | * Note: this function polls at 100 msec intervals. | |
177 | */ | |
178 | int wait_for_device_probe(void) | |
179 | { | |
180 | /* wait for the known devices to complete their probing */ | |
181 | while (driver_probe_done() != 0) | |
182 | msleep(100); | |
183 | async_synchronize_full(); | |
184 | return 0; | |
185 | } | |
186 | ||
d779249e GKH |
187 | /** |
188 | * driver_probe_device - attempt to bind device & driver together | |
189 | * @drv: driver to bind a device to | |
190 | * @dev: device to try to bind to the driver | |
191 | * | |
49b420a1 ML |
192 | * This function returns -ENODEV if the device is not registered, |
193 | * 1 if the device is bound sucessfully and 0 otherwise. | |
d779249e GKH |
194 | * |
195 | * This function must be called with @dev->sem held. When called for a | |
196 | * USB interface, @dev->parent->sem must be held as well. | |
197 | */ | |
4a3ad20c | 198 | int driver_probe_device(struct device_driver *drv, struct device *dev) |
d779249e | 199 | { |
d779249e GKH |
200 | int ret = 0; |
201 | ||
f2eaae19 AS |
202 | if (!device_is_registered(dev)) |
203 | return -ENODEV; | |
d779249e | 204 | |
7dc72b28 | 205 | pr_debug("bus: '%s': %s: matched device %s with driver %s\n", |
1e0b2cf9 | 206 | drv->bus->name, __func__, dev_name(dev), drv->name); |
d779249e | 207 | |
21c7f30b | 208 | ret = really_probe(dev, drv); |
d779249e | 209 | |
0d3e5a2e | 210 | return ret; |
07e4a3e2 PM |
211 | } |
212 | ||
4a3ad20c | 213 | static int __device_attach(struct device_driver *drv, void *data) |
2287c322 | 214 | { |
4a3ad20c | 215 | struct device *dev = data; |
49b420a1 ML |
216 | |
217 | if (!driver_match_device(drv, dev)) | |
218 | return 0; | |
219 | ||
0d3e5a2e | 220 | return driver_probe_device(drv, dev); |
2287c322 PM |
221 | } |
222 | ||
07e4a3e2 | 223 | /** |
4a3ad20c GKH |
224 | * device_attach - try to attach device to a driver. |
225 | * @dev: device. | |
07e4a3e2 | 226 | * |
4a3ad20c GKH |
227 | * Walk the list of drivers that the bus has and call |
228 | * driver_probe_device() for each pair. If a compatible | |
229 | * pair is found, break out and return. | |
0d3e5a2e | 230 | * |
4a3ad20c GKH |
231 | * Returns 1 if the device was bound to a driver; |
232 | * 0 if no matching device was found; | |
233 | * -ENODEV if the device is not registered. | |
bf74ad5b | 234 | * |
4a3ad20c | 235 | * When called for a USB interface, @dev->parent->sem must be held. |
07e4a3e2 | 236 | */ |
4a3ad20c | 237 | int device_attach(struct device *dev) |
07e4a3e2 | 238 | { |
0d3e5a2e PM |
239 | int ret = 0; |
240 | ||
241 | down(&dev->sem); | |
07e4a3e2 | 242 | if (dev->driver) { |
f86db396 AM |
243 | ret = device_bind_driver(dev); |
244 | if (ret == 0) | |
245 | ret = 1; | |
c6a46696 CH |
246 | else { |
247 | dev->driver = NULL; | |
248 | ret = 0; | |
249 | } | |
21c7f30b | 250 | } else { |
5adc55da | 251 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); |
21c7f30b | 252 | } |
0d3e5a2e PM |
253 | up(&dev->sem); |
254 | return ret; | |
2287c322 | 255 | } |
4a3ad20c | 256 | EXPORT_SYMBOL_GPL(device_attach); |
2287c322 | 257 | |
4a3ad20c | 258 | static int __driver_attach(struct device *dev, void *data) |
2287c322 | 259 | { |
4a3ad20c | 260 | struct device_driver *drv = data; |
0d3e5a2e PM |
261 | |
262 | /* | |
263 | * Lock device and try to bind to it. We drop the error | |
264 | * here and always return 0, because we need to keep trying | |
265 | * to bind to devices and some drivers will return an error | |
266 | * simply if it didn't support the device. | |
267 | * | |
268 | * driver_probe_device() will spit a warning if there | |
269 | * is an error. | |
270 | */ | |
271 | ||
49b420a1 | 272 | if (!driver_match_device(drv, dev)) |
6cd49586 AV |
273 | return 0; |
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 | /** | |
4a3ad20c GKH |
288 | * driver_attach - try to bind driver to devices. |
289 | * @drv: driver. | |
07e4a3e2 | 290 | * |
4a3ad20c GKH |
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 | */ |
4a3ad20c | 296 | int driver_attach(struct device_driver *drv) |
07e4a3e2 | 297 | { |
f86db396 | 298 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 299 | } |
4a3ad20c | 300 | EXPORT_SYMBOL_GPL(driver_attach); |
07e4a3e2 | 301 | |
ab71c6f0 | 302 | /* |
4a3ad20c GKH |
303 | * __device_release_driver() must be called with @dev->sem held. |
304 | * When called for a USB interface, @dev->parent->sem must be held as well. | |
07e4a3e2 | 305 | */ |
4a3ad20c | 306 | static void __device_release_driver(struct device *dev) |
07e4a3e2 | 307 | { |
4a3ad20c | 308 | struct device_driver *drv; |
07e4a3e2 | 309 | |
ef2c5174 | 310 | drv = dev->driver; |
c95a6b05 | 311 | if (drv) { |
1901fb26 | 312 | driver_sysfs_remove(dev); |
0d3e5a2e | 313 | |
116af378 | 314 | if (dev->bus) |
c6f7e72a | 315 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
316 | BUS_NOTIFY_UNBIND_DRIVER, |
317 | dev); | |
318 | ||
0f836ca4 | 319 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
320 | dev->bus->remove(dev); |
321 | else if (drv->remove) | |
0d3e5a2e | 322 | drv->remove(dev); |
9ac7849e | 323 | devres_release_all(dev); |
0d3e5a2e | 324 | dev->driver = NULL; |
cda5e83f | 325 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 326 | } |
07e4a3e2 PM |
327 | } |
328 | ||
ab71c6f0 | 329 | /** |
4a3ad20c GKH |
330 | * device_release_driver - manually detach device from driver. |
331 | * @dev: device. | |
ab71c6f0 | 332 | * |
4a3ad20c GKH |
333 | * Manually detach device from driver. |
334 | * When called for a USB interface, @dev->parent->sem must be held. | |
ab71c6f0 | 335 | */ |
4a3ad20c | 336 | void device_release_driver(struct device *dev) |
94e7b1c5 | 337 | { |
c95a6b05 AS |
338 | /* |
339 | * If anyone calls device_release_driver() recursively from | |
340 | * within their ->remove callback for the same device, they | |
341 | * will deadlock right here. | |
342 | */ | |
343 | down(&dev->sem); | |
344 | __device_release_driver(dev); | |
345 | up(&dev->sem); | |
94e7b1c5 | 346 | } |
4a3ad20c | 347 | EXPORT_SYMBOL_GPL(device_release_driver); |
c95a6b05 | 348 | |
07e4a3e2 PM |
349 | /** |
350 | * driver_detach - detach driver from all devices it controls. | |
351 | * @drv: driver. | |
352 | */ | |
4a3ad20c | 353 | void driver_detach(struct device_driver *drv) |
07e4a3e2 | 354 | { |
4a3ad20c | 355 | struct device *dev; |
c95a6b05 AS |
356 | |
357 | for (;;) { | |
e5dd1278 GKH |
358 | spin_lock(&drv->p->klist_devices.k_lock); |
359 | if (list_empty(&drv->p->klist_devices.k_list)) { | |
360 | spin_unlock(&drv->p->klist_devices.k_lock); | |
c95a6b05 AS |
361 | break; |
362 | } | |
cda5e83f GKH |
363 | dev = list_entry(drv->p->klist_devices.k_list.prev, |
364 | struct device, knode_driver.n_node); | |
c95a6b05 | 365 | get_device(dev); |
e5dd1278 | 366 | spin_unlock(&drv->p->klist_devices.k_lock); |
c95a6b05 | 367 | |
bf74ad5b AS |
368 | if (dev->parent) /* Needed for USB */ |
369 | down(&dev->parent->sem); | |
c95a6b05 AS |
370 | down(&dev->sem); |
371 | if (dev->driver == drv) | |
372 | __device_release_driver(dev); | |
373 | up(&dev->sem); | |
bf74ad5b AS |
374 | if (dev->parent) |
375 | up(&dev->parent->sem); | |
c95a6b05 AS |
376 | put_device(dev); |
377 | } | |
07e4a3e2 | 378 | } |