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> | |
20 | ||
21 | #include "base.h" | |
22 | #include "power/power.h" | |
23 | ||
24 | #define to_drv(node) container_of(node, struct device_driver, kobj.entry) | |
25 | ||
26 | ||
27 | /** | |
28 | * device_bind_driver - bind a driver to one device. | |
29 | * @dev: device. | |
30 | * | |
31 | * Allow manual attachment of a driver to a device. | |
32 | * Caller must have already set @dev->driver. | |
33 | * | |
34 | * Note that this does not modify the bus reference count | |
35 | * nor take the bus's rwsem. Please verify those are accounted | |
36 | * for before calling this. (It is ok to call with no other effort | |
37 | * from a driver's probe() method.) | |
0d3e5a2e PM |
38 | * |
39 | * This function must be called with @dev->sem held. | |
07e4a3e2 | 40 | */ |
f86db396 | 41 | int device_bind_driver(struct device *dev) |
07e4a3e2 | 42 | { |
f86db396 AM |
43 | int ret; |
44 | ||
45 | if (klist_node_attached(&dev->knode_driver)) { | |
46 | printk(KERN_WARNING "%s: device %s already bound\n", | |
47 | __FUNCTION__, kobject_name(&dev->kobj)); | |
48 | return 0; | |
49 | } | |
4c898c7f | 50 | |
07e4a3e2 | 51 | pr_debug("bound device '%s' to driver '%s'\n", |
52 | dev->bus_id, dev->driver->name); | |
d856f1e3 | 53 | klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices); |
f86db396 | 54 | ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
07e4a3e2 | 55 | kobject_name(&dev->kobj)); |
f86db396 AM |
56 | if (ret == 0) { |
57 | ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj, | |
58 | "driver"); | |
59 | if (ret) | |
60 | sysfs_remove_link(&dev->driver->kobj, | |
61 | kobject_name(&dev->kobj)); | |
62 | } | |
63 | return ret; | |
07e4a3e2 | 64 | } |
65 | ||
66 | /** | |
67 | * driver_probe_device - attempt to bind device & driver. | |
68 | * @drv: driver. | |
69 | * @dev: device. | |
70 | * | |
71 | * First, we call the bus's match function, if one present, which | |
72 | * should compare the device IDs the driver supports with the | |
73 | * device IDs of the device. Note we don't do this ourselves | |
74 | * because we don't know the format of the ID structures, nor what | |
75 | * is to be considered a match and what is not. | |
76 | * | |
0d3e5a2e PM |
77 | * This function returns 1 if a match is found, an error if one |
78 | * occurs (that is not -ENODEV or -ENXIO), and 0 otherwise. | |
79 | * | |
bf74ad5b AS |
80 | * This function must be called with @dev->sem held. When called |
81 | * for a USB interface, @dev->parent->sem must be held as well. | |
07e4a3e2 | 82 | */ |
afdce75f | 83 | int driver_probe_device(struct device_driver * drv, struct device * dev) |
07e4a3e2 | 84 | { |
0d3e5a2e | 85 | int ret = 0; |
07e4a3e2 | 86 | |
87 | if (drv->bus->match && !drv->bus->match(dev, drv)) | |
0d3e5a2e | 88 | goto Done; |
07e4a3e2 | 89 | |
0d3e5a2e PM |
90 | pr_debug("%s: Matched Device %s with Driver %s\n", |
91 | drv->bus->name, dev->bus_id, drv->name); | |
07e4a3e2 | 92 | dev->driver = drv; |
594c8281 RK |
93 | if (dev->bus->probe) { |
94 | ret = dev->bus->probe(dev); | |
95 | if (ret) { | |
96 | dev->driver = NULL; | |
97 | goto ProbeFailed; | |
98 | } | |
99 | } else if (drv->probe) { | |
0d3e5a2e PM |
100 | ret = drv->probe(dev); |
101 | if (ret) { | |
07e4a3e2 | 102 | dev->driver = NULL; |
0d3e5a2e | 103 | goto ProbeFailed; |
07e4a3e2 | 104 | } |
105 | } | |
f86db396 AM |
106 | if (device_bind_driver(dev)) { |
107 | printk(KERN_ERR "%s: device_bind_driver(%s) failed\n", | |
108 | __FUNCTION__, dev->bus_id); | |
109 | /* How does undo a ->probe? We're screwed. */ | |
110 | } | |
0d3e5a2e PM |
111 | ret = 1; |
112 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
113 | drv->bus->name, dev->bus_id, drv->name); | |
114 | goto Done; | |
115 | ||
116 | ProbeFailed: | |
117 | if (ret == -ENODEV || ret == -ENXIO) { | |
118 | /* Driver matched, but didn't support device | |
119 | * or device not found. | |
120 | * Not an error; keep going. | |
121 | */ | |
122 | ret = 0; | |
123 | } else { | |
124 | /* driver matched but the probe failed */ | |
125 | printk(KERN_WARNING | |
126 | "%s: probe of %s failed with error %d\n", | |
127 | drv->name, dev->bus_id, ret); | |
128 | } | |
129 | Done: | |
130 | return ret; | |
07e4a3e2 | 131 | } |
132 | ||
2287c322 | 133 | static int __device_attach(struct device_driver * drv, void * data) |
134 | { | |
135 | struct device * dev = data; | |
0d3e5a2e | 136 | return driver_probe_device(drv, dev); |
2287c322 | 137 | } |
138 | ||
07e4a3e2 | 139 | /** |
140 | * device_attach - try to attach device to a driver. | |
141 | * @dev: device. | |
142 | * | |
143 | * Walk the list of drivers that the bus has and call | |
144 | * driver_probe_device() for each pair. If a compatible | |
145 | * pair is found, break out and return. | |
0d3e5a2e | 146 | * |
ca2b94ba HR |
147 | * Returns 1 if the device was bound to a driver; |
148 | * 0 if no matching device was found; error code otherwise. | |
bf74ad5b AS |
149 | * |
150 | * When called for a USB interface, @dev->parent->sem must be held. | |
07e4a3e2 | 151 | */ |
152 | int device_attach(struct device * dev) | |
153 | { | |
0d3e5a2e PM |
154 | int ret = 0; |
155 | ||
156 | down(&dev->sem); | |
07e4a3e2 | 157 | if (dev->driver) { |
f86db396 AM |
158 | ret = device_bind_driver(dev); |
159 | if (ret == 0) | |
160 | ret = 1; | |
0d3e5a2e PM |
161 | } else |
162 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
163 | up(&dev->sem); | |
164 | return ret; | |
2287c322 | 165 | } |
166 | ||
167 | static int __driver_attach(struct device * dev, void * data) | |
168 | { | |
169 | struct device_driver * drv = data; | |
0d3e5a2e PM |
170 | |
171 | /* | |
172 | * Lock device and try to bind to it. We drop the error | |
173 | * here and always return 0, because we need to keep trying | |
174 | * to bind to devices and some drivers will return an error | |
175 | * simply if it didn't support the device. | |
176 | * | |
177 | * driver_probe_device() will spit a warning if there | |
178 | * is an error. | |
179 | */ | |
180 | ||
bf74ad5b AS |
181 | if (dev->parent) /* Needed for USB */ |
182 | down(&dev->parent->sem); | |
0d3e5a2e PM |
183 | down(&dev->sem); |
184 | if (!dev->driver) | |
185 | driver_probe_device(drv, dev); | |
186 | up(&dev->sem); | |
bf74ad5b AS |
187 | if (dev->parent) |
188 | up(&dev->parent->sem); | |
0d3e5a2e | 189 | |
07e4a3e2 | 190 | return 0; |
191 | } | |
192 | ||
193 | /** | |
194 | * driver_attach - try to bind driver to devices. | |
195 | * @drv: driver. | |
196 | * | |
197 | * Walk the list of devices that the bus has on it and try to | |
198 | * match the driver with each one. If driver_probe_device() | |
199 | * returns 0 and the @dev->driver is set, we've found a | |
200 | * compatible pair. | |
07e4a3e2 | 201 | */ |
f86db396 | 202 | int driver_attach(struct device_driver * drv) |
07e4a3e2 | 203 | { |
f86db396 | 204 | return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 | 205 | } |
206 | ||
207 | /** | |
208 | * device_release_driver - manually detach device from driver. | |
209 | * @dev: device. | |
210 | * | |
211 | * Manually detach device from driver. | |
c95a6b05 AS |
212 | * |
213 | * __device_release_driver() must be called with @dev->sem held. | |
bf74ad5b AS |
214 | * When called for a USB interface, @dev->parent->sem must be held |
215 | * as well. | |
07e4a3e2 | 216 | */ |
c95a6b05 AS |
217 | |
218 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 219 | { |
0d3e5a2e | 220 | struct device_driver * drv; |
07e4a3e2 | 221 | |
c95a6b05 AS |
222 | drv = dev->driver; |
223 | if (drv) { | |
224 | get_driver(drv); | |
0d3e5a2e PM |
225 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); |
226 | sysfs_remove_link(&dev->kobj, "driver"); | |
c95a6b05 | 227 | klist_remove(&dev->knode_driver); |
0d3e5a2e | 228 | |
0f836ca4 | 229 | if (dev->bus && dev->bus->remove) |
594c8281 RK |
230 | dev->bus->remove(dev); |
231 | else if (drv->remove) | |
0d3e5a2e PM |
232 | drv->remove(dev); |
233 | dev->driver = NULL; | |
c95a6b05 | 234 | put_driver(drv); |
0d3e5a2e | 235 | } |
07e4a3e2 | 236 | } |
237 | ||
c95a6b05 | 238 | void device_release_driver(struct device * dev) |
94e7b1c5 | 239 | { |
c95a6b05 AS |
240 | /* |
241 | * If anyone calls device_release_driver() recursively from | |
242 | * within their ->remove callback for the same device, they | |
243 | * will deadlock right here. | |
244 | */ | |
245 | down(&dev->sem); | |
246 | __device_release_driver(dev); | |
247 | up(&dev->sem); | |
94e7b1c5 | 248 | } |
249 | ||
c95a6b05 | 250 | |
07e4a3e2 | 251 | /** |
252 | * driver_detach - detach driver from all devices it controls. | |
253 | * @drv: driver. | |
254 | */ | |
255 | void driver_detach(struct device_driver * drv) | |
256 | { | |
c95a6b05 AS |
257 | struct device * dev; |
258 | ||
259 | for (;;) { | |
2b08c8d0 | 260 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 261 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 262 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
263 | break; |
264 | } | |
265 | dev = list_entry(drv->klist_devices.k_list.prev, | |
266 | struct device, knode_driver.n_node); | |
267 | get_device(dev); | |
2b08c8d0 | 268 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 | 269 | |
bf74ad5b AS |
270 | if (dev->parent) /* Needed for USB */ |
271 | down(&dev->parent->sem); | |
c95a6b05 AS |
272 | down(&dev->sem); |
273 | if (dev->driver == drv) | |
274 | __device_release_driver(dev); | |
275 | up(&dev->sem); | |
bf74ad5b AS |
276 | if (dev->parent) |
277 | up(&dev->parent->sem); | |
c95a6b05 AS |
278 | put_device(dev); |
279 | } | |
07e4a3e2 | 280 | } |
281 | ||
282 | ||
07e4a3e2 | 283 | EXPORT_SYMBOL_GPL(device_bind_driver); |
284 | EXPORT_SYMBOL_GPL(device_release_driver); | |
285 | EXPORT_SYMBOL_GPL(device_attach); | |
286 | EXPORT_SYMBOL_GPL(driver_attach); | |
287 |