Commit | Line | Data |
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07e4a3e2 | 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> |
07e4a3e2 | 21 | |
22 | #include "base.h" | |
23 | #include "power/power.h" | |
24 | ||
25 | #define to_drv(node) container_of(node, struct device_driver, kobj.entry) | |
26 | ||
27 | ||
28 | /** | |
29 | * device_bind_driver - bind a driver to one device. | |
30 | * @dev: device. | |
31 | * | |
32 | * Allow manual attachment of a driver to a device. | |
33 | * Caller must have already set @dev->driver. | |
34 | * | |
35 | * Note that this does not modify the bus reference count | |
36 | * nor take the bus's rwsem. Please verify those are accounted | |
37 | * for before calling this. (It is ok to call with no other effort | |
38 | * from a driver's probe() method.) | |
0d3e5a2e PM |
39 | * |
40 | * This function must be called with @dev->sem held. | |
07e4a3e2 | 41 | */ |
f86db396 | 42 | int device_bind_driver(struct device *dev) |
07e4a3e2 | 43 | { |
f86db396 AM |
44 | int ret; |
45 | ||
46 | if (klist_node_attached(&dev->knode_driver)) { | |
47 | printk(KERN_WARNING "%s: device %s already bound\n", | |
48 | __FUNCTION__, kobject_name(&dev->kobj)); | |
49 | return 0; | |
50 | } | |
4c898c7f | 51 | |
07e4a3e2 | 52 | pr_debug("bound device '%s' to driver '%s'\n", |
53 | dev->bus_id, dev->driver->name); | |
d856f1e3 | 54 | klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); |
f86db396 | 55 | ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
07e4a3e2 | 56 | kobject_name(&dev->kobj)); |
f86db396 AM |
57 | if (ret == 0) { |
58 | ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj, | |
59 | "driver"); | |
60 | if (ret) | |
61 | sysfs_remove_link(&dev->driver->kobj, | |
62 | kobject_name(&dev->kobj)); | |
63 | } | |
64 | return ret; | |
07e4a3e2 | 65 | } |
66 | ||
d779249e GKH |
67 | struct stupid_thread_structure { |
68 | struct device_driver *drv; | |
69 | struct device *dev; | |
70 | }; | |
71 | ||
72 | static atomic_t probe_count = ATOMIC_INIT(0); | |
73 | static int really_probe(void *void_data) | |
07e4a3e2 | 74 | { |
d779249e GKH |
75 | struct stupid_thread_structure *data = void_data; |
76 | struct device_driver *drv = data->drv; | |
77 | struct device *dev = data->dev; | |
0d3e5a2e | 78 | int ret = 0; |
07e4a3e2 | 79 | |
d779249e GKH |
80 | atomic_inc(&probe_count); |
81 | pr_debug("%s: Probing driver %s with device %s\n", | |
82 | drv->bus->name, drv->name, dev->bus_id); | |
07e4a3e2 | 83 | |
07e4a3e2 | 84 | dev->driver = drv; |
594c8281 RK |
85 | if (dev->bus->probe) { |
86 | ret = dev->bus->probe(dev); | |
87 | if (ret) { | |
88 | dev->driver = NULL; | |
d779249e | 89 | goto probe_failed; |
594c8281 RK |
90 | } |
91 | } else if (drv->probe) { | |
0d3e5a2e PM |
92 | ret = drv->probe(dev); |
93 | if (ret) { | |
07e4a3e2 | 94 | dev->driver = NULL; |
d779249e | 95 | goto probe_failed; |
07e4a3e2 | 96 | } |
97 | } | |
f86db396 AM |
98 | if (device_bind_driver(dev)) { |
99 | printk(KERN_ERR "%s: device_bind_driver(%s) failed\n", | |
100 | __FUNCTION__, dev->bus_id); | |
101 | /* How does undo a ->probe? We're screwed. */ | |
102 | } | |
0d3e5a2e PM |
103 | ret = 1; |
104 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
105 | drv->bus->name, dev->bus_id, drv->name); | |
d779249e | 106 | goto done; |
0d3e5a2e | 107 | |
d779249e | 108 | probe_failed: |
0d3e5a2e PM |
109 | if (ret == -ENODEV || ret == -ENXIO) { |
110 | /* Driver matched, but didn't support device | |
111 | * or device not found. | |
112 | * Not an error; keep going. | |
113 | */ | |
114 | ret = 0; | |
115 | } else { | |
116 | /* driver matched but the probe failed */ | |
117 | printk(KERN_WARNING | |
118 | "%s: probe of %s failed with error %d\n", | |
119 | drv->name, dev->bus_id, ret); | |
120 | } | |
d779249e GKH |
121 | done: |
122 | kfree(data); | |
123 | atomic_dec(&probe_count); | |
124 | return ret; | |
125 | } | |
126 | ||
127 | /** | |
128 | * driver_probe_done | |
129 | * Determine if the probe sequence is finished or not. | |
130 | * | |
131 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
132 | */ | |
133 | int driver_probe_done(void) | |
134 | { | |
135 | pr_debug("%s: probe_count = %d\n", __FUNCTION__, | |
136 | atomic_read(&probe_count)); | |
137 | if (atomic_read(&probe_count)) | |
138 | return -EBUSY; | |
139 | return 0; | |
140 | } | |
141 | ||
142 | /** | |
143 | * driver_probe_device - attempt to bind device & driver together | |
144 | * @drv: driver to bind a device to | |
145 | * @dev: device to try to bind to the driver | |
146 | * | |
147 | * First, we call the bus's match function, if one present, which should | |
148 | * compare the device IDs the driver supports with the device IDs of the | |
149 | * device. Note we don't do this ourselves because we don't know the | |
150 | * format of the ID structures, nor what is to be considered a match and | |
151 | * what is not. | |
152 | * | |
153 | * This function returns 1 if a match is found, an error if one occurs | |
154 | * (that is not -ENODEV or -ENXIO), and 0 otherwise. | |
155 | * | |
156 | * This function must be called with @dev->sem held. When called for a | |
157 | * USB interface, @dev->parent->sem must be held as well. | |
158 | */ | |
159 | int driver_probe_device(struct device_driver * drv, struct device * dev) | |
160 | { | |
161 | struct stupid_thread_structure *data; | |
162 | struct task_struct *probe_task; | |
163 | int ret = 0; | |
164 | ||
f2eaae19 AS |
165 | if (!device_is_registered(dev)) |
166 | return -ENODEV; | |
d779249e GKH |
167 | if (drv->bus->match && !drv->bus->match(dev, drv)) |
168 | goto done; | |
169 | ||
170 | pr_debug("%s: Matched Device %s with Driver %s\n", | |
171 | drv->bus->name, dev->bus_id, drv->name); | |
172 | ||
173 | data = kmalloc(sizeof(*data), GFP_KERNEL); | |
4d664238 AM |
174 | if (!data) |
175 | return -ENOMEM; | |
d779249e GKH |
176 | data->drv = drv; |
177 | data->dev = dev; | |
178 | ||
179 | if (drv->multithread_probe) { | |
180 | probe_task = kthread_run(really_probe, data, | |
181 | "probe-%s", dev->bus_id); | |
182 | if (IS_ERR(probe_task)) | |
0fbf116d | 183 | ret = really_probe(data); |
d779249e GKH |
184 | } else |
185 | ret = really_probe(data); | |
186 | ||
187 | done: | |
0d3e5a2e | 188 | return ret; |
07e4a3e2 | 189 | } |
190 | ||
2287c322 | 191 | static int __device_attach(struct device_driver * drv, void * data) |
192 | { | |
193 | struct device * dev = data; | |
0d3e5a2e | 194 | return driver_probe_device(drv, dev); |
2287c322 | 195 | } |
196 | ||
07e4a3e2 | 197 | /** |
198 | * device_attach - try to attach device to a driver. | |
199 | * @dev: device. | |
200 | * | |
201 | * Walk the list of drivers that the bus has and call | |
202 | * driver_probe_device() for each pair. If a compatible | |
203 | * pair is found, break out and return. | |
0d3e5a2e | 204 | * |
ca2b94ba HR |
205 | * Returns 1 if the device was bound to a driver; |
206 | * 0 if no matching device was found; error code otherwise. | |
bf74ad5b AS |
207 | * |
208 | * When called for a USB interface, @dev->parent->sem must be held. | |
07e4a3e2 | 209 | */ |
210 | int device_attach(struct device * dev) | |
211 | { | |
0d3e5a2e PM |
212 | int ret = 0; |
213 | ||
214 | down(&dev->sem); | |
07e4a3e2 | 215 | if (dev->driver) { |
f86db396 AM |
216 | ret = device_bind_driver(dev); |
217 | if (ret == 0) | |
218 | ret = 1; | |
0d3e5a2e PM |
219 | } else |
220 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
221 | up(&dev->sem); | |
222 | return ret; | |
2287c322 | 223 | } |
224 | ||
225 | static int __driver_attach(struct device * dev, void * data) | |
226 | { | |
227 | struct device_driver * drv = data; | |
0d3e5a2e PM |
228 | |
229 | /* | |
230 | * Lock device and try to bind to it. We drop the error | |
231 | * here and always return 0, because we need to keep trying | |
232 | * to bind to devices and some drivers will return an error | |
233 | * simply if it didn't support the device. | |
234 | * | |
235 | * driver_probe_device() will spit a warning if there | |
236 | * is an error. | |
237 | */ | |
238 | ||
bf74ad5b AS |
239 | if (dev->parent) /* Needed for USB */ |
240 | down(&dev->parent->sem); | |
0d3e5a2e PM |
241 | down(&dev->sem); |
242 | if (!dev->driver) | |
243 | driver_probe_device(drv, dev); | |
244 | up(&dev->sem); | |
bf74ad5b AS |
245 | if (dev->parent) |
246 | up(&dev->parent->sem); | |
0d3e5a2e | 247 | |
07e4a3e2 | 248 | return 0; |
249 | } | |
250 | ||
251 | /** | |
252 | * driver_attach - try to bind driver to devices. | |
253 | * @drv: driver. | |
254 | * | |
255 | * Walk the list of devices that the bus has on it and try to | |
256 | * match the driver with each one. If driver_probe_device() | |
257 | * returns 0 and the @dev->driver is set, we've found a | |
258 | * compatible pair. | |
07e4a3e2 | 259 | */ |
f86db396 | 260 | int driver_attach(struct device_driver * drv) |
07e4a3e2 | 261 | { |
f86db396 | 262 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 263 | } |
264 | ||
265 | /** | |
266 | * device_release_driver - manually detach device from driver. | |
267 | * @dev: device. | |
268 | * | |
269 | * Manually detach device from driver. | |
c95a6b05 AS |
270 | * |
271 | * __device_release_driver() must be called with @dev->sem held. | |
bf74ad5b AS |
272 | * When called for a USB interface, @dev->parent->sem must be held |
273 | * as well. | |
07e4a3e2 | 274 | */ |
c95a6b05 AS |
275 | |
276 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 277 | { |
0d3e5a2e | 278 | struct device_driver * drv; |
07e4a3e2 | 279 | |
c95a6b05 AS |
280 | drv = dev->driver; |
281 | if (drv) { | |
282 | get_driver(drv); | |
0d3e5a2e PM |
283 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); |
284 | sysfs_remove_link(&dev->kobj, "driver"); | |
c95a6b05 | 285 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 286 | |
0f836ca4 | 287 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
288 | dev->bus->remove(dev); |
289 | else if (drv->remove) | |
0d3e5a2e PM |
290 | drv->remove(dev); |
291 | dev->driver = NULL; | |
c95a6b05 | 292 | put_driver(drv); |
0d3e5a2e | 293 | } |
07e4a3e2 | 294 | } |
295 | ||
c95a6b05 | 296 | void device_release_driver(struct device * dev) |
94e7b1c5 | 297 | { |
c95a6b05 AS |
298 | /* |
299 | * If anyone calls device_release_driver() recursively from | |
300 | * within their ->remove callback for the same device, they | |
301 | * will deadlock right here. | |
302 | */ | |
303 | down(&dev->sem); | |
304 | __device_release_driver(dev); | |
305 | up(&dev->sem); | |
94e7b1c5 | 306 | } |
307 | ||
c95a6b05 | 308 | |
07e4a3e2 | 309 | /** |
310 | * driver_detach - detach driver from all devices it controls. | |
311 | * @drv: driver. | |
312 | */ | |
313 | void driver_detach(struct device_driver * drv) | |
314 | { | |
c95a6b05 AS |
315 | struct device * dev; |
316 | ||
317 | for (;;) { | |
2b08c8d0 | 318 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 319 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 320 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
321 | break; |
322 | } | |
323 | dev = list_entry(drv->klist_devices.k_list.prev, | |
324 | struct device, knode_driver.n_node); | |
325 | get_device(dev); | |
2b08c8d0 | 326 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 | 327 | |
bf74ad5b AS |
328 | if (dev->parent) /* Needed for USB */ |
329 | down(&dev->parent->sem); | |
c95a6b05 AS |
330 | down(&dev->sem); |
331 | if (dev->driver == drv) | |
332 | __device_release_driver(dev); | |
333 | up(&dev->sem); | |
bf74ad5b AS |
334 | if (dev->parent) |
335 | up(&dev->parent->sem); | |
c95a6b05 AS |
336 | put_device(dev); |
337 | } | |
07e4a3e2 | 338 | } |
339 | ||
340 | ||
07e4a3e2 | 341 | EXPORT_SYMBOL_GPL(device_bind_driver); |
342 | EXPORT_SYMBOL_GPL(device_release_driver); | |
343 | EXPORT_SYMBOL_GPL(device_attach); | |
344 | EXPORT_SYMBOL_GPL(driver_attach); | |
345 |