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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 | * | |
68 | * This function must be called with @dev->sem held. | |
07e4a3e2 | 69 | */ |
afdce75f | 70 | int driver_probe_device(struct device_driver * drv, struct device * dev) |
07e4a3e2 | 71 | { |
0d3e5a2e | 72 | int ret = 0; |
07e4a3e2 PM |
73 | |
74 | if (drv->bus->match && !drv->bus->match(dev, drv)) | |
0d3e5a2e | 75 | goto Done; |
07e4a3e2 | 76 | |
0d3e5a2e PM |
77 | pr_debug("%s: Matched Device %s with Driver %s\n", |
78 | drv->bus->name, dev->bus_id, drv->name); | |
07e4a3e2 PM |
79 | dev->driver = drv; |
80 | if (drv->probe) { | |
0d3e5a2e PM |
81 | ret = drv->probe(dev); |
82 | if (ret) { | |
07e4a3e2 | 83 | dev->driver = NULL; |
0d3e5a2e | 84 | goto ProbeFailed; |
07e4a3e2 PM |
85 | } |
86 | } | |
07e4a3e2 | 87 | device_bind_driver(dev); |
0d3e5a2e PM |
88 | ret = 1; |
89 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
90 | drv->bus->name, dev->bus_id, drv->name); | |
91 | goto Done; | |
92 | ||
93 | ProbeFailed: | |
94 | if (ret == -ENODEV || ret == -ENXIO) { | |
95 | /* Driver matched, but didn't support device | |
96 | * or device not found. | |
97 | * Not an error; keep going. | |
98 | */ | |
99 | ret = 0; | |
100 | } else { | |
101 | /* driver matched but the probe failed */ | |
102 | printk(KERN_WARNING | |
103 | "%s: probe of %s failed with error %d\n", | |
104 | drv->name, dev->bus_id, ret); | |
105 | } | |
106 | Done: | |
107 | return ret; | |
07e4a3e2 PM |
108 | } |
109 | ||
2287c322 PM |
110 | static int __device_attach(struct device_driver * drv, void * data) |
111 | { | |
112 | struct device * dev = data; | |
0d3e5a2e | 113 | return driver_probe_device(drv, dev); |
2287c322 PM |
114 | } |
115 | ||
07e4a3e2 PM |
116 | /** |
117 | * device_attach - try to attach device to a driver. | |
118 | * @dev: device. | |
119 | * | |
120 | * Walk the list of drivers that the bus has and call | |
121 | * driver_probe_device() for each pair. If a compatible | |
122 | * pair is found, break out and return. | |
0d3e5a2e | 123 | * |
ca2b94ba HR |
124 | * Returns 1 if the device was bound to a driver; |
125 | * 0 if no matching device was found; error code otherwise. | |
07e4a3e2 PM |
126 | */ |
127 | int device_attach(struct device * dev) | |
128 | { | |
0d3e5a2e PM |
129 | int ret = 0; |
130 | ||
131 | down(&dev->sem); | |
07e4a3e2 PM |
132 | if (dev->driver) { |
133 | device_bind_driver(dev); | |
0d3e5a2e PM |
134 | ret = 1; |
135 | } else | |
136 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
137 | up(&dev->sem); | |
138 | return ret; | |
2287c322 PM |
139 | } |
140 | ||
141 | static int __driver_attach(struct device * dev, void * data) | |
142 | { | |
143 | struct device_driver * drv = data; | |
0d3e5a2e PM |
144 | |
145 | /* | |
146 | * Lock device and try to bind to it. We drop the error | |
147 | * here and always return 0, because we need to keep trying | |
148 | * to bind to devices and some drivers will return an error | |
149 | * simply if it didn't support the device. | |
150 | * | |
151 | * driver_probe_device() will spit a warning if there | |
152 | * is an error. | |
153 | */ | |
154 | ||
155 | down(&dev->sem); | |
156 | if (!dev->driver) | |
157 | driver_probe_device(drv, dev); | |
158 | up(&dev->sem); | |
159 | ||
07e4a3e2 PM |
160 | return 0; |
161 | } | |
162 | ||
163 | /** | |
164 | * driver_attach - try to bind driver to devices. | |
165 | * @drv: driver. | |
166 | * | |
167 | * Walk the list of devices that the bus has on it and try to | |
168 | * match the driver with each one. If driver_probe_device() | |
169 | * returns 0 and the @dev->driver is set, we've found a | |
170 | * compatible pair. | |
07e4a3e2 PM |
171 | */ |
172 | void driver_attach(struct device_driver * drv) | |
173 | { | |
2287c322 | 174 | bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 PM |
175 | } |
176 | ||
177 | /** | |
178 | * device_release_driver - manually detach device from driver. | |
179 | * @dev: device. | |
180 | * | |
181 | * Manually detach device from driver. | |
c95a6b05 AS |
182 | * |
183 | * __device_release_driver() must be called with @dev->sem held. | |
07e4a3e2 | 184 | */ |
c95a6b05 AS |
185 | |
186 | static void __device_release_driver(struct device * dev) | |
07e4a3e2 | 187 | { |
0d3e5a2e | 188 | struct device_driver * drv; |
07e4a3e2 | 189 | |
c95a6b05 AS |
190 | drv = dev->driver; |
191 | if (drv) { | |
192 | get_driver(drv); | |
0d3e5a2e PM |
193 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); |
194 | sysfs_remove_link(&dev->kobj, "driver"); | |
c95a6b05 | 195 | klist_remove(&dev->knode_driver); |
0d3e5a2e PM |
196 | |
197 | if (drv->remove) | |
198 | drv->remove(dev); | |
199 | dev->driver = NULL; | |
c95a6b05 | 200 | put_driver(drv); |
0d3e5a2e | 201 | } |
07e4a3e2 PM |
202 | } |
203 | ||
c95a6b05 | 204 | void device_release_driver(struct device * dev) |
94e7b1c5 | 205 | { |
c95a6b05 AS |
206 | /* |
207 | * If anyone calls device_release_driver() recursively from | |
208 | * within their ->remove callback for the same device, they | |
209 | * will deadlock right here. | |
210 | */ | |
211 | down(&dev->sem); | |
212 | __device_release_driver(dev); | |
213 | up(&dev->sem); | |
94e7b1c5 PM |
214 | } |
215 | ||
c95a6b05 | 216 | |
07e4a3e2 PM |
217 | /** |
218 | * driver_detach - detach driver from all devices it controls. | |
219 | * @drv: driver. | |
220 | */ | |
221 | void driver_detach(struct device_driver * drv) | |
222 | { | |
c95a6b05 AS |
223 | struct device * dev; |
224 | ||
225 | for (;;) { | |
2b08c8d0 | 226 | spin_lock(&drv->klist_devices.k_lock); |
c95a6b05 | 227 | if (list_empty(&drv->klist_devices.k_list)) { |
2b08c8d0 | 228 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
229 | break; |
230 | } | |
231 | dev = list_entry(drv->klist_devices.k_list.prev, | |
232 | struct device, knode_driver.n_node); | |
233 | get_device(dev); | |
2b08c8d0 | 234 | spin_unlock(&drv->klist_devices.k_lock); |
c95a6b05 AS |
235 | |
236 | down(&dev->sem); | |
237 | if (dev->driver == drv) | |
238 | __device_release_driver(dev); | |
239 | up(&dev->sem); | |
240 | put_device(dev); | |
241 | } | |
07e4a3e2 PM |
242 | } |
243 | ||
244 | ||
07e4a3e2 PM |
245 | EXPORT_SYMBOL_GPL(device_bind_driver); |
246 | EXPORT_SYMBOL_GPL(device_release_driver); | |
247 | EXPORT_SYMBOL_GPL(device_attach); | |
248 | EXPORT_SYMBOL_GPL(driver_attach); | |
249 |