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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 | { | |
43 | pr_debug("bound device '%s' to driver '%s'\n", | |
44 | dev->bus_id, dev->driver->name); | |
94e7b1c5 | 45 | klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver); |
07e4a3e2 PM |
46 | sysfs_create_link(&dev->driver->kobj, &dev->kobj, |
47 | kobject_name(&dev->kobj)); | |
48 | sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver"); | |
49 | } | |
50 | ||
51 | /** | |
52 | * driver_probe_device - attempt to bind device & driver. | |
53 | * @drv: driver. | |
54 | * @dev: device. | |
55 | * | |
56 | * First, we call the bus's match function, if one present, which | |
57 | * should compare the device IDs the driver supports with the | |
58 | * device IDs of the device. Note we don't do this ourselves | |
59 | * because we don't know the format of the ID structures, nor what | |
60 | * is to be considered a match and what is not. | |
61 | * | |
0d3e5a2e PM |
62 | * |
63 | * This function returns 1 if a match is found, an error if one | |
64 | * occurs (that is not -ENODEV or -ENXIO), and 0 otherwise. | |
65 | * | |
66 | * This function must be called with @dev->sem held. | |
07e4a3e2 | 67 | */ |
0d3e5a2e | 68 | static int driver_probe_device(struct device_driver * drv, struct device * dev) |
07e4a3e2 | 69 | { |
0d3e5a2e | 70 | int ret = 0; |
07e4a3e2 PM |
71 | |
72 | if (drv->bus->match && !drv->bus->match(dev, drv)) | |
0d3e5a2e | 73 | goto Done; |
07e4a3e2 | 74 | |
0d3e5a2e PM |
75 | pr_debug("%s: Matched Device %s with Driver %s\n", |
76 | drv->bus->name, dev->bus_id, drv->name); | |
07e4a3e2 PM |
77 | dev->driver = drv; |
78 | if (drv->probe) { | |
0d3e5a2e PM |
79 | ret = drv->probe(dev); |
80 | if (ret) { | |
07e4a3e2 | 81 | dev->driver = NULL; |
0d3e5a2e | 82 | goto ProbeFailed; |
07e4a3e2 PM |
83 | } |
84 | } | |
07e4a3e2 | 85 | device_bind_driver(dev); |
0d3e5a2e PM |
86 | ret = 1; |
87 | pr_debug("%s: Bound Device %s to Driver %s\n", | |
88 | drv->bus->name, dev->bus_id, drv->name); | |
89 | goto Done; | |
90 | ||
91 | ProbeFailed: | |
92 | if (ret == -ENODEV || ret == -ENXIO) { | |
93 | /* Driver matched, but didn't support device | |
94 | * or device not found. | |
95 | * Not an error; keep going. | |
96 | */ | |
97 | ret = 0; | |
98 | } else { | |
99 | /* driver matched but the probe failed */ | |
100 | printk(KERN_WARNING | |
101 | "%s: probe of %s failed with error %d\n", | |
102 | drv->name, dev->bus_id, ret); | |
103 | } | |
104 | Done: | |
105 | return ret; | |
07e4a3e2 PM |
106 | } |
107 | ||
2287c322 PM |
108 | static int __device_attach(struct device_driver * drv, void * data) |
109 | { | |
110 | struct device * dev = data; | |
0d3e5a2e | 111 | return driver_probe_device(drv, dev); |
2287c322 PM |
112 | } |
113 | ||
07e4a3e2 PM |
114 | /** |
115 | * device_attach - try to attach device to a driver. | |
116 | * @dev: device. | |
117 | * | |
118 | * Walk the list of drivers that the bus has and call | |
119 | * driver_probe_device() for each pair. If a compatible | |
120 | * pair is found, break out and return. | |
0d3e5a2e PM |
121 | * |
122 | * Returns 1 if the device was bound to a driver; 0 otherwise. | |
07e4a3e2 PM |
123 | */ |
124 | int device_attach(struct device * dev) | |
125 | { | |
0d3e5a2e PM |
126 | int ret = 0; |
127 | ||
128 | down(&dev->sem); | |
07e4a3e2 PM |
129 | if (dev->driver) { |
130 | device_bind_driver(dev); | |
0d3e5a2e PM |
131 | ret = 1; |
132 | } else | |
133 | ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); | |
134 | up(&dev->sem); | |
135 | return ret; | |
2287c322 PM |
136 | } |
137 | ||
138 | static int __driver_attach(struct device * dev, void * data) | |
139 | { | |
140 | struct device_driver * drv = data; | |
0d3e5a2e PM |
141 | |
142 | /* | |
143 | * Lock device and try to bind to it. We drop the error | |
144 | * here and always return 0, because we need to keep trying | |
145 | * to bind to devices and some drivers will return an error | |
146 | * simply if it didn't support the device. | |
147 | * | |
148 | * driver_probe_device() will spit a warning if there | |
149 | * is an error. | |
150 | */ | |
151 | ||
152 | down(&dev->sem); | |
153 | if (!dev->driver) | |
154 | driver_probe_device(drv, dev); | |
155 | up(&dev->sem); | |
156 | ||
157 | ||
07e4a3e2 PM |
158 | return 0; |
159 | } | |
160 | ||
161 | /** | |
162 | * driver_attach - try to bind driver to devices. | |
163 | * @drv: driver. | |
164 | * | |
165 | * Walk the list of devices that the bus has on it and try to | |
166 | * match the driver with each one. If driver_probe_device() | |
167 | * returns 0 and the @dev->driver is set, we've found a | |
168 | * compatible pair. | |
07e4a3e2 PM |
169 | */ |
170 | void driver_attach(struct device_driver * drv) | |
171 | { | |
2287c322 | 172 | bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); |
07e4a3e2 PM |
173 | } |
174 | ||
175 | /** | |
176 | * device_release_driver - manually detach device from driver. | |
177 | * @dev: device. | |
178 | * | |
179 | * Manually detach device from driver. | |
180 | * Note that this is called without incrementing the bus | |
181 | * reference count nor taking the bus's rwsem. Be sure that | |
182 | * those are accounted for before calling this function. | |
183 | */ | |
184 | void device_release_driver(struct device * dev) | |
185 | { | |
0d3e5a2e | 186 | struct device_driver * drv; |
07e4a3e2 PM |
187 | |
188 | down(&dev->sem); | |
0d3e5a2e PM |
189 | if (dev->driver) { |
190 | drv = dev->driver; | |
191 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); | |
192 | sysfs_remove_link(&dev->kobj, "driver"); | |
193 | klist_del(&dev->knode_driver); | |
194 | ||
195 | if (drv->remove) | |
196 | drv->remove(dev); | |
197 | dev->driver = NULL; | |
198 | } | |
07e4a3e2 PM |
199 | up(&dev->sem); |
200 | } | |
201 | ||
94e7b1c5 PM |
202 | static int __remove_driver(struct device * dev, void * unused) |
203 | { | |
204 | device_release_driver(dev); | |
205 | return 0; | |
206 | } | |
207 | ||
07e4a3e2 PM |
208 | /** |
209 | * driver_detach - detach driver from all devices it controls. | |
210 | * @drv: driver. | |
211 | */ | |
212 | void driver_detach(struct device_driver * drv) | |
213 | { | |
94e7b1c5 | 214 | driver_for_each_device(drv, NULL, NULL, __remove_driver); |
07e4a3e2 PM |
215 | } |
216 | ||
217 | ||
07e4a3e2 PM |
218 | EXPORT_SYMBOL_GPL(device_bind_driver); |
219 | EXPORT_SYMBOL_GPL(device_release_driver); | |
220 | EXPORT_SYMBOL_GPL(device_attach); | |
221 | EXPORT_SYMBOL_GPL(driver_attach); | |
222 |