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