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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> | |
21 | #include <linux/module.h> | |
d779249e | 22 | #include <linux/kthread.h> |
735a7ffb | 23 | #include <linux/wait.h> |
07e4a3e2 PM |
24 | |
25 | #include "base.h" | |
26 | #include "power/power.h" | |
27 | ||
07e4a3e2 | 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", | |
2b3a302a | 33 | __func__, kobject_name(&dev->kobj)); |
1901fb26 | 34 | return; |
f86db396 | 35 | } |
4c898c7f | 36 | |
7dc72b28 | 37 | pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->bus_id, |
2b3a302a | 38 | __func__, dev->driver->name); |
116af378 BH |
39 | |
40 | if (dev->bus) | |
c6f7e72a | 41 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
42 | BUS_NOTIFY_BOUND_DRIVER, dev); |
43 | ||
e5dd1278 | 44 | klist_add_tail(&dev->knode_driver, &dev->driver->p->klist_devices); |
1901fb26 KS |
45 | } |
46 | ||
47 | static int driver_sysfs_add(struct device *dev) | |
48 | { | |
49 | int ret; | |
50 | ||
e5dd1278 | 51 | ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj, |
07e4a3e2 | 52 | kobject_name(&dev->kobj)); |
f86db396 | 53 | if (ret == 0) { |
e5dd1278 | 54 | ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj, |
f86db396 AM |
55 | "driver"); |
56 | if (ret) | |
e5dd1278 | 57 | sysfs_remove_link(&dev->driver->p->kobj, |
f86db396 AM |
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) { | |
e5dd1278 | 68 | sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj)); |
1901fb26 KS |
69 | sysfs_remove_link(&dev->kobj, "driver"); |
70 | } | |
71 | } | |
72 | ||
73 | /** | |
4a3ad20c GKH |
74 | * device_bind_driver - bind a driver to one device. |
75 | * @dev: device. | |
1901fb26 | 76 | * |
4a3ad20c GKH |
77 | * Allow manual attachment of a driver to a device. |
78 | * Caller must have already set @dev->driver. | |
1901fb26 | 79 | * |
4a3ad20c GKH |
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.) | |
1901fb26 | 84 | * |
4a3ad20c | 85 | * This function must be called with @dev->sem held. |
1901fb26 KS |
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 | 95 | } |
4a3ad20c | 96 | EXPORT_SYMBOL_GPL(device_bind_driver); |
1901fb26 | 97 | |
d779249e | 98 | static atomic_t probe_count = ATOMIC_INIT(0); |
735a7ffb AM |
99 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
100 | ||
21c7f30b | 101 | static int really_probe(struct device *dev, struct device_driver *drv) |
07e4a3e2 | 102 | { |
0d3e5a2e | 103 | int ret = 0; |
07e4a3e2 | 104 | |
d779249e | 105 | atomic_inc(&probe_count); |
7dc72b28 | 106 | pr_debug("bus: '%s': %s: probing driver %s with device %s\n", |
2b3a302a | 107 | drv->bus->name, __func__, drv->name, dev->bus_id); |
9ac7849e | 108 | WARN_ON(!list_empty(&dev->devres_head)); |
07e4a3e2 | 109 | |
07e4a3e2 | 110 | dev->driver = drv; |
1901fb26 KS |
111 | if (driver_sysfs_add(dev)) { |
112 | printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", | |
2b3a302a | 113 | __func__, dev->bus_id); |
1901fb26 KS |
114 | goto probe_failed; |
115 | } | |
116 | ||
594c8281 RK |
117 | if (dev->bus->probe) { |
118 | ret = dev->bus->probe(dev); | |
1901fb26 | 119 | if (ret) |
d779249e | 120 | goto probe_failed; |
594c8281 | 121 | } else if (drv->probe) { |
0d3e5a2e | 122 | ret = drv->probe(dev); |
1901fb26 | 123 | if (ret) |
d779249e | 124 | goto probe_failed; |
f86db396 | 125 | } |
1901fb26 KS |
126 | |
127 | driver_bound(dev); | |
0d3e5a2e | 128 | ret = 1; |
7dc72b28 | 129 | pr_debug("bus: '%s': %s: bound device %s to driver %s\n", |
2b3a302a | 130 | drv->bus->name, __func__, dev->bus_id, drv->name); |
d779249e | 131 | goto done; |
0d3e5a2e | 132 | |
d779249e | 133 | probe_failed: |
9ac7849e | 134 | devres_release_all(dev); |
1901fb26 KS |
135 | driver_sysfs_remove(dev); |
136 | dev->driver = NULL; | |
137 | ||
c578abbc | 138 | if (ret != -ENODEV && ret != -ENXIO) { |
0d3e5a2e PM |
139 | /* driver matched but the probe failed */ |
140 | printk(KERN_WARNING | |
141 | "%s: probe of %s failed with error %d\n", | |
142 | drv->name, dev->bus_id, ret); | |
143 | } | |
c578abbc CH |
144 | /* |
145 | * Ignore errors returned by ->probe so that the next driver can try | |
146 | * its luck. | |
147 | */ | |
148 | ret = 0; | |
d779249e | 149 | done: |
d779249e | 150 | atomic_dec(&probe_count); |
735a7ffb | 151 | wake_up(&probe_waitqueue); |
d779249e GKH |
152 | return ret; |
153 | } | |
154 | ||
155 | /** | |
156 | * driver_probe_done | |
157 | * Determine if the probe sequence is finished or not. | |
158 | * | |
159 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
160 | */ | |
161 | int driver_probe_done(void) | |
162 | { | |
2b3a302a | 163 | pr_debug("%s: probe_count = %d\n", __func__, |
d779249e GKH |
164 | atomic_read(&probe_count)); |
165 | if (atomic_read(&probe_count)) | |
166 | return -EBUSY; | |
167 | return 0; | |
168 | } | |
169 | ||
170 | /** | |
171 | * driver_probe_device - attempt to bind device & driver together | |
172 | * @drv: driver to bind a device to | |
173 | * @dev: device to try to bind to the driver | |
174 | * | |
175 | * First, we call the bus's match function, if one present, which should | |
176 | * compare the device IDs the driver supports with the device IDs of the | |
177 | * device. Note we don't do this ourselves because we don't know the | |
178 | * format of the ID structures, nor what is to be considered a match and | |
179 | * what is not. | |
180 | * | |
21c7f30b CH |
181 | * This function returns 1 if a match is found, -ENODEV if the device is |
182 | * not registered, and 0 otherwise. | |
d779249e GKH |
183 | * |
184 | * This function must be called with @dev->sem held. When called for a | |
185 | * USB interface, @dev->parent->sem must be held as well. | |
186 | */ | |
4a3ad20c | 187 | int driver_probe_device(struct device_driver *drv, struct device *dev) |
d779249e | 188 | { |
d779249e GKH |
189 | int ret = 0; |
190 | ||
f2eaae19 AS |
191 | if (!device_is_registered(dev)) |
192 | return -ENODEV; | |
d779249e GKH |
193 | if (drv->bus->match && !drv->bus->match(dev, drv)) |
194 | goto done; | |
195 | ||
7dc72b28 | 196 | pr_debug("bus: '%s': %s: matched device %s with driver %s\n", |
2b3a302a | 197 | drv->bus->name, __func__, dev->bus_id, drv->name); |
d779249e | 198 | |
21c7f30b | 199 | ret = really_probe(dev, drv); |
d779249e GKH |
200 | |
201 | done: | |
0d3e5a2e | 202 | return ret; |
07e4a3e2 PM |
203 | } |
204 | ||
4a3ad20c | 205 | static int __device_attach(struct device_driver *drv, void *data) |
2287c322 | 206 | { |
4a3ad20c | 207 | struct device *dev = data; |
0d3e5a2e | 208 | return driver_probe_device(drv, dev); |
2287c322 PM |
209 | } |
210 | ||
07e4a3e2 | 211 | /** |
4a3ad20c GKH |
212 | * device_attach - try to attach device to a driver. |
213 | * @dev: device. | |
07e4a3e2 | 214 | * |
4a3ad20c GKH |
215 | * Walk the list of drivers that the bus has and call |
216 | * driver_probe_device() for each pair. If a compatible | |
217 | * pair is found, break out and return. | |
0d3e5a2e | 218 | * |
4a3ad20c GKH |
219 | * Returns 1 if the device was bound to a driver; |
220 | * 0 if no matching device was found; | |
221 | * -ENODEV if the device is not registered. | |
bf74ad5b | 222 | * |
4a3ad20c | 223 | * When called for a USB interface, @dev->parent->sem must be held. |
07e4a3e2 | 224 | */ |
4a3ad20c | 225 | int device_attach(struct device *dev) |
07e4a3e2 | 226 | { |
0d3e5a2e PM |
227 | int ret = 0; |
228 | ||
229 | down(&dev->sem); | |
07e4a3e2 | 230 | if (dev->driver) { |
f86db396 AM |
231 | ret = device_bind_driver(dev); |
232 | if (ret == 0) | |
233 | ret = 1; | |
c6a46696 CH |
234 | else { |
235 | dev->driver = NULL; | |
236 | ret = 0; | |
237 | } | |
21c7f30b | 238 | } else { |
5adc55da | 239 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); |
21c7f30b | 240 | } |
0d3e5a2e PM |
241 | up(&dev->sem); |
242 | return ret; | |
2287c322 | 243 | } |
4a3ad20c | 244 | EXPORT_SYMBOL_GPL(device_attach); |
2287c322 | 245 | |
4a3ad20c | 246 | static int __driver_attach(struct device *dev, void *data) |
2287c322 | 247 | { |
4a3ad20c | 248 | struct device_driver *drv = data; |
0d3e5a2e PM |
249 | |
250 | /* | |
251 | * Lock device and try to bind to it. We drop the error | |
252 | * here and always return 0, because we need to keep trying | |
253 | * to bind to devices and some drivers will return an error | |
254 | * simply if it didn't support the device. | |
255 | * | |
256 | * driver_probe_device() will spit a warning if there | |
257 | * is an error. | |
258 | */ | |
259 | ||
bf74ad5b AS |
260 | if (dev->parent) /* Needed for USB */ |
261 | down(&dev->parent->sem); | |
0d3e5a2e PM |
262 | down(&dev->sem); |
263 | if (!dev->driver) | |
264 | driver_probe_device(drv, dev); | |
265 | up(&dev->sem); | |
bf74ad5b AS |
266 | if (dev->parent) |
267 | up(&dev->parent->sem); | |
0d3e5a2e | 268 | |
07e4a3e2 PM |
269 | return 0; |
270 | } | |
271 | ||
272 | /** | |
4a3ad20c GKH |
273 | * driver_attach - try to bind driver to devices. |
274 | * @drv: driver. | |
07e4a3e2 | 275 | * |
4a3ad20c GKH |
276 | * Walk the list of devices that the bus has on it and try to |
277 | * match the driver with each one. If driver_probe_device() | |
278 | * returns 0 and the @dev->driver is set, we've found a | |
279 | * compatible pair. | |
07e4a3e2 | 280 | */ |
4a3ad20c | 281 | int driver_attach(struct device_driver *drv) |
07e4a3e2 | 282 | { |
f86db396 | 283 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 284 | } |
4a3ad20c | 285 | EXPORT_SYMBOL_GPL(driver_attach); |
07e4a3e2 | 286 | |
ab71c6f0 | 287 | /* |
4a3ad20c GKH |
288 | * __device_release_driver() must be called with @dev->sem held. |
289 | * When called for a USB interface, @dev->parent->sem must be held as well. | |
07e4a3e2 | 290 | */ |
4a3ad20c | 291 | static void __device_release_driver(struct device *dev) |
07e4a3e2 | 292 | { |
4a3ad20c | 293 | struct device_driver *drv; |
07e4a3e2 | 294 | |
ef2c5174 | 295 | drv = dev->driver; |
c95a6b05 | 296 | if (drv) { |
1901fb26 | 297 | driver_sysfs_remove(dev); |
0d3e5a2e | 298 | sysfs_remove_link(&dev->kobj, "driver"); |
0d3e5a2e | 299 | |
116af378 | 300 | if (dev->bus) |
c6f7e72a | 301 | blocking_notifier_call_chain(&dev->bus->p->bus_notifier, |
116af378 BH |
302 | BUS_NOTIFY_UNBIND_DRIVER, |
303 | dev); | |
304 | ||
0f836ca4 | 305 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
306 | dev->bus->remove(dev); |
307 | else if (drv->remove) | |
0d3e5a2e | 308 | drv->remove(dev); |
9ac7849e | 309 | devres_release_all(dev); |
0d3e5a2e | 310 | dev->driver = NULL; |
ef2c5174 | 311 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 312 | } |
07e4a3e2 PM |
313 | } |
314 | ||
ab71c6f0 | 315 | /** |
4a3ad20c GKH |
316 | * device_release_driver - manually detach device from driver. |
317 | * @dev: device. | |
ab71c6f0 | 318 | * |
4a3ad20c GKH |
319 | * Manually detach device from driver. |
320 | * When called for a USB interface, @dev->parent->sem must be held. | |
ab71c6f0 | 321 | */ |
4a3ad20c | 322 | void device_release_driver(struct device *dev) |
94e7b1c5 | 323 | { |
c95a6b05 AS |
324 | /* |
325 | * If anyone calls device_release_driver() recursively from | |
326 | * within their ->remove callback for the same device, they | |
327 | * will deadlock right here. | |
328 | */ | |
329 | down(&dev->sem); | |
330 | __device_release_driver(dev); | |
331 | up(&dev->sem); | |
94e7b1c5 | 332 | } |
4a3ad20c | 333 | EXPORT_SYMBOL_GPL(device_release_driver); |
c95a6b05 | 334 | |
07e4a3e2 PM |
335 | /** |
336 | * driver_detach - detach driver from all devices it controls. | |
337 | * @drv: driver. | |
338 | */ | |
4a3ad20c | 339 | void driver_detach(struct device_driver *drv) |
07e4a3e2 | 340 | { |
4a3ad20c | 341 | struct device *dev; |
c95a6b05 AS |
342 | |
343 | for (;;) { | |
e5dd1278 GKH |
344 | spin_lock(&drv->p->klist_devices.k_lock); |
345 | if (list_empty(&drv->p->klist_devices.k_list)) { | |
346 | spin_unlock(&drv->p->klist_devices.k_lock); | |
c95a6b05 AS |
347 | break; |
348 | } | |
e5dd1278 | 349 | dev = list_entry(drv->p->klist_devices.k_list.prev, |
c95a6b05 AS |
350 | struct device, knode_driver.n_node); |
351 | get_device(dev); | |
e5dd1278 | 352 | spin_unlock(&drv->p->klist_devices.k_lock); |
c95a6b05 | 353 | |
bf74ad5b AS |
354 | if (dev->parent) /* Needed for USB */ |
355 | down(&dev->parent->sem); | |
c95a6b05 AS |
356 | down(&dev->sem); |
357 | if (dev->driver == drv) | |
358 | __device_release_driver(dev); | |
359 | up(&dev->sem); | |
bf74ad5b AS |
360 | if (dev->parent) |
361 | up(&dev->parent->sem); | |
c95a6b05 AS |
362 | put_device(dev); |
363 | } | |
07e4a3e2 | 364 | } |