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 | ||
29 | /** | |
30 | * device_bind_driver - bind a driver to one device. | |
31 | * @dev: device. | |
32 | * | |
33 | * Allow manual attachment of a driver to a device. | |
34 | * Caller must have already set @dev->driver. | |
35 | * | |
36 | * Note that this does not modify the bus reference count | |
37 | * nor take the bus's rwsem. Please verify those are accounted | |
38 | * for before calling this. (It is ok to call with no other effort | |
39 | * from a driver's probe() method.) | |
0d3e5a2e PM |
40 | * |
41 | * This function must be called with @dev->sem held. | |
07e4a3e2 | 42 | */ |
f86db396 | 43 | int device_bind_driver(struct device *dev) |
07e4a3e2 | 44 | { |
f86db396 AM |
45 | int ret; |
46 | ||
47 | if (klist_node_attached(&dev->knode_driver)) { | |
48 | printk(KERN_WARNING "%s: device %s already bound\n", | |
49 | __FUNCTION__, kobject_name(&dev->kobj)); | |
50 | return 0; | |
51 | } | |
4c898c7f | 52 | |
07e4a3e2 PM |
53 | pr_debug("bound device '%s' to driver '%s'\n", |
54 | dev->bus_id, dev->driver->name); | |
d856f1e3 | 55 | klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); |
f86db396 | 56 | ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
07e4a3e2 | 57 | kobject_name(&dev->kobj)); |
f86db396 AM |
58 | if (ret == 0) { |
59 | ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj, | |
60 | "driver"); | |
61 | if (ret) | |
62 | sysfs_remove_link(&dev->driver->kobj, | |
63 | kobject_name(&dev->kobj)); | |
64 | } | |
65 | return ret; | |
07e4a3e2 PM |
66 | } |
67 | ||
d779249e GKH |
68 | struct stupid_thread_structure { |
69 | struct device_driver *drv; | |
70 | struct device *dev; | |
71 | }; | |
72 | ||
73 | static atomic_t probe_count = ATOMIC_INIT(0); | |
735a7ffb AM |
74 | static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); |
75 | ||
d779249e | 76 | static int really_probe(void *void_data) |
07e4a3e2 | 77 | { |
d779249e GKH |
78 | struct stupid_thread_structure *data = void_data; |
79 | struct device_driver *drv = data->drv; | |
80 | struct device *dev = data->dev; | |
0d3e5a2e | 81 | int ret = 0; |
07e4a3e2 | 82 | |
d779249e GKH |
83 | atomic_inc(&probe_count); |
84 | pr_debug("%s: Probing driver %s with device %s\n", | |
85 | drv->bus->name, drv->name, dev->bus_id); | |
07e4a3e2 | 86 | |
07e4a3e2 | 87 | dev->driver = drv; |
594c8281 RK |
88 | if (dev->bus->probe) { |
89 | ret = dev->bus->probe(dev); | |
90 | if (ret) { | |
91 | dev->driver = NULL; | |
d779249e | 92 | goto probe_failed; |
594c8281 RK |
93 | } |
94 | } else if (drv->probe) { | |
0d3e5a2e PM |
95 | ret = drv->probe(dev); |
96 | if (ret) { | |
07e4a3e2 | 97 | dev->driver = NULL; |
d779249e | 98 | goto probe_failed; |
07e4a3e2 PM |
99 | } |
100 | } | |
f86db396 AM |
101 | if (device_bind_driver(dev)) { |
102 | printk(KERN_ERR "%s: device_bind_driver(%s) failed\n", | |
103 | __FUNCTION__, dev->bus_id); | |
104 | /* How does undo a ->probe? We're screwed. */ | |
105 | } | |
0d3e5a2e PM |
106 | ret = 1; |
107 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
108 | drv->bus->name, dev->bus_id, drv->name); | |
d779249e | 109 | goto done; |
0d3e5a2e | 110 | |
d779249e | 111 | probe_failed: |
0d3e5a2e PM |
112 | if (ret == -ENODEV || ret == -ENXIO) { |
113 | /* Driver matched, but didn't support device | |
114 | * or device not found. | |
115 | * Not an error; keep going. | |
116 | */ | |
117 | ret = 0; | |
118 | } else { | |
119 | /* driver matched but the probe failed */ | |
120 | printk(KERN_WARNING | |
121 | "%s: probe of %s failed with error %d\n", | |
122 | drv->name, dev->bus_id, ret); | |
123 | } | |
d779249e GKH |
124 | done: |
125 | kfree(data); | |
126 | atomic_dec(&probe_count); | |
735a7ffb | 127 | wake_up(&probe_waitqueue); |
d779249e GKH |
128 | return ret; |
129 | } | |
130 | ||
131 | /** | |
132 | * driver_probe_done | |
133 | * Determine if the probe sequence is finished or not. | |
134 | * | |
135 | * Should somehow figure out how to use a semaphore, not an atomic variable... | |
136 | */ | |
137 | int driver_probe_done(void) | |
138 | { | |
139 | pr_debug("%s: probe_count = %d\n", __FUNCTION__, | |
140 | atomic_read(&probe_count)); | |
141 | if (atomic_read(&probe_count)) | |
142 | return -EBUSY; | |
143 | return 0; | |
144 | } | |
145 | ||
146 | /** | |
147 | * driver_probe_device - attempt to bind device & driver together | |
148 | * @drv: driver to bind a device to | |
149 | * @dev: device to try to bind to the driver | |
150 | * | |
151 | * First, we call the bus's match function, if one present, which should | |
152 | * compare the device IDs the driver supports with the device IDs of the | |
153 | * device. Note we don't do this ourselves because we don't know the | |
154 | * format of the ID structures, nor what is to be considered a match and | |
155 | * what is not. | |
156 | * | |
157 | * This function returns 1 if a match is found, an error if one occurs | |
158 | * (that is not -ENODEV or -ENXIO), and 0 otherwise. | |
159 | * | |
160 | * This function must be called with @dev->sem held. When called for a | |
161 | * USB interface, @dev->parent->sem must be held as well. | |
162 | */ | |
163 | int driver_probe_device(struct device_driver * drv, struct device * dev) | |
164 | { | |
165 | struct stupid_thread_structure *data; | |
166 | struct task_struct *probe_task; | |
167 | int ret = 0; | |
168 | ||
f2eaae19 AS |
169 | if (!device_is_registered(dev)) |
170 | return -ENODEV; | |
d779249e GKH |
171 | if (drv->bus->match && !drv->bus->match(dev, drv)) |
172 | goto done; | |
173 | ||
174 | pr_debug("%s: Matched Device %s with Driver %s\n", | |
175 | drv->bus->name, dev->bus_id, drv->name); | |
176 | ||
177 | data = kmalloc(sizeof(*data), GFP_KERNEL); | |
4d664238 AM |
178 | if (!data) |
179 | return -ENOMEM; | |
d779249e GKH |
180 | data->drv = drv; |
181 | data->dev = dev; | |
182 | ||
183 | if (drv->multithread_probe) { | |
184 | probe_task = kthread_run(really_probe, data, | |
185 | "probe-%s", dev->bus_id); | |
186 | if (IS_ERR(probe_task)) | |
0fbf116d | 187 | ret = really_probe(data); |
d779249e GKH |
188 | } else |
189 | ret = really_probe(data); | |
190 | ||
191 | done: | |
0d3e5a2e | 192 | return ret; |
07e4a3e2 PM |
193 | } |
194 | ||
2287c322 PM |
195 | static int __device_attach(struct device_driver * drv, void * data) |
196 | { | |
197 | struct device * dev = data; | |
0d3e5a2e | 198 | return driver_probe_device(drv, dev); |
2287c322 PM |
199 | } |
200 | ||
07e4a3e2 PM |
201 | /** |
202 | * device_attach - try to attach device to a driver. | |
203 | * @dev: device. | |
204 | * | |
205 | * Walk the list of drivers that the bus has and call | |
206 | * driver_probe_device() for each pair. If a compatible | |
207 | * pair is found, break out and return. | |
0d3e5a2e | 208 | * |
ca2b94ba HR |
209 | * Returns 1 if the device was bound to a driver; |
210 | * 0 if no matching device was found; error code otherwise. | |
bf74ad5b AS |
211 | * |
212 | * When called for a USB interface, @dev->parent->sem must be held. | |
07e4a3e2 PM |
213 | */ |
214 | int device_attach(struct device * dev) | |
215 | { | |
0d3e5a2e PM |
216 | int ret = 0; |
217 | ||
218 | down(&dev->sem); | |
07e4a3e2 | 219 | if (dev->driver) { |
f86db396 AM |
220 | ret = device_bind_driver(dev); |
221 | if (ret == 0) | |
222 | ret = 1; | |
0d3e5a2e PM |
223 | } else |
224 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
225 | up(&dev->sem); | |
226 | return ret; | |
2287c322 PM |
227 | } |
228 | ||
229 | static int __driver_attach(struct device * dev, void * data) | |
230 | { | |
231 | struct device_driver * drv = data; | |
0d3e5a2e PM |
232 | |
233 | /* | |
234 | * Lock device and try to bind to it. We drop the error | |
235 | * here and always return 0, because we need to keep trying | |
236 | * to bind to devices and some drivers will return an error | |
237 | * simply if it didn't support the device. | |
238 | * | |
239 | * driver_probe_device() will spit a warning if there | |
240 | * is an error. | |
241 | */ | |
242 | ||
bf74ad5b AS |
243 | if (dev->parent) /* Needed for USB */ |
244 | down(&dev->parent->sem); | |
0d3e5a2e PM |
245 | down(&dev->sem); |
246 | if (!dev->driver) | |
247 | driver_probe_device(drv, dev); | |
248 | up(&dev->sem); | |
bf74ad5b AS |
249 | if (dev->parent) |
250 | up(&dev->parent->sem); | |
0d3e5a2e | 251 | |
07e4a3e2 PM |
252 | return 0; |
253 | } | |
254 | ||
255 | /** | |
256 | * driver_attach - try to bind driver to devices. | |
257 | * @drv: driver. | |
258 | * | |
259 | * Walk the list of devices that the bus has on it and try to | |
260 | * match the driver with each one. If driver_probe_device() | |
261 | * returns 0 and the @dev->driver is set, we've found a | |
262 | * compatible pair. | |
07e4a3e2 | 263 | */ |
f86db396 | 264 | int driver_attach(struct device_driver * drv) |
07e4a3e2 | 265 | { |
f86db396 | 266 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 PM |
267 | } |
268 | ||
269 | /** | |
270 | * device_release_driver - manually detach device from driver. | |
271 | * @dev: device. | |
272 | * | |
273 | * Manually detach device from driver. | |
c95a6b05 AS |
274 | * |
275 | * __device_release_driver() must be called with @dev->sem held. | |
bf74ad5b AS |
276 | * When called for a USB interface, @dev->parent->sem must be held |
277 | * as well. | |
07e4a3e2 | 278 | */ |
c95a6b05 AS |
279 | |
280 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 281 | { |
0d3e5a2e | 282 | struct device_driver * drv; |
07e4a3e2 | 283 | |
c95a6b05 AS |
284 | drv = dev->driver; |
285 | if (drv) { | |
286 | get_driver(drv); | |
0d3e5a2e PM |
287 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); |
288 | sysfs_remove_link(&dev->kobj, "driver"); | |
c95a6b05 | 289 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 290 | |
0f836ca4 | 291 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
292 | dev->bus->remove(dev); |
293 | else if (drv->remove) | |
0d3e5a2e PM |
294 | drv->remove(dev); |
295 | dev->driver = NULL; | |
c95a6b05 | 296 | put_driver(drv); |
0d3e5a2e | 297 | } |
07e4a3e2 PM |
298 | } |
299 | ||
c95a6b05 | 300 | void device_release_driver(struct device * dev) |
94e7b1c5 | 301 | { |
c95a6b05 AS |
302 | /* |
303 | * If anyone calls device_release_driver() recursively from | |
304 | * within their ->remove callback for the same device, they | |
305 | * will deadlock right here. | |
306 | */ | |
307 | down(&dev->sem); | |
308 | __device_release_driver(dev); | |
309 | up(&dev->sem); | |
94e7b1c5 PM |
310 | } |
311 | ||
c95a6b05 | 312 | |
07e4a3e2 PM |
313 | /** |
314 | * driver_detach - detach driver from all devices it controls. | |
315 | * @drv: driver. | |
316 | */ | |
317 | void driver_detach(struct device_driver * drv) | |
318 | { | |
c95a6b05 AS |
319 | struct device * dev; |
320 | ||
321 | for (;;) { | |
2b08c8d0 | 322 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 323 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 324 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
325 | break; |
326 | } | |
327 | dev = list_entry(drv->klist_devices.k_list.prev, | |
328 | struct device, knode_driver.n_node); | |
329 | get_device(dev); | |
2b08c8d0 | 330 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 | 331 | |
bf74ad5b AS |
332 | if (dev->parent) /* Needed for USB */ |
333 | down(&dev->parent->sem); | |
c95a6b05 AS |
334 | down(&dev->sem); |
335 | if (dev->driver == drv) | |
336 | __device_release_driver(dev); | |
337 | up(&dev->sem); | |
bf74ad5b AS |
338 | if (dev->parent) |
339 | up(&dev->parent->sem); | |
c95a6b05 AS |
340 | put_device(dev); |
341 | } | |
07e4a3e2 PM |
342 | } |
343 | ||
735a7ffb AM |
344 | #ifdef CONFIG_PCI_MULTITHREAD_PROBE |
345 | static int __init wait_for_probes(void) | |
346 | { | |
347 | DEFINE_WAIT(wait); | |
348 | ||
349 | printk(KERN_INFO "%s: waiting for %d threads\n", __FUNCTION__, | |
350 | atomic_read(&probe_count)); | |
351 | if (!atomic_read(&probe_count)) | |
352 | return 0; | |
353 | while (atomic_read(&probe_count)) { | |
354 | prepare_to_wait(&probe_waitqueue, &wait, TASK_UNINTERRUPTIBLE); | |
355 | if (atomic_read(&probe_count)) | |
356 | schedule(); | |
357 | } | |
358 | finish_wait(&probe_waitqueue, &wait); | |
359 | return 0; | |
360 | } | |
361 | ||
362 | core_initcall_sync(wait_for_probes); | |
363 | postcore_initcall_sync(wait_for_probes); | |
364 | arch_initcall_sync(wait_for_probes); | |
365 | subsys_initcall_sync(wait_for_probes); | |
366 | fs_initcall_sync(wait_for_probes); | |
367 | device_initcall_sync(wait_for_probes); | |
368 | late_initcall_sync(wait_for_probes); | |
369 | #endif | |
07e4a3e2 | 370 | |
07e4a3e2 PM |
371 | EXPORT_SYMBOL_GPL(device_bind_driver); |
372 | EXPORT_SYMBOL_GPL(device_release_driver); | |
373 | EXPORT_SYMBOL_GPL(device_attach); | |
374 | EXPORT_SYMBOL_GPL(driver_attach); | |
375 |