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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.) | |
38 | */ | |
39 | void device_bind_driver(struct device * dev) | |
40 | { | |
41 | pr_debug("bound device '%s' to driver '%s'\n", | |
42 | dev->bus_id, dev->driver->name); | |
43 | list_add_tail(&dev->driver_list, &dev->driver->devices); | |
44 | sysfs_create_link(&dev->driver->kobj, &dev->kobj, | |
45 | kobject_name(&dev->kobj)); | |
46 | sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver"); | |
47 | } | |
48 | ||
49 | /** | |
50 | * driver_probe_device - attempt to bind device & driver. | |
51 | * @drv: driver. | |
52 | * @dev: device. | |
53 | * | |
54 | * First, we call the bus's match function, if one present, which | |
55 | * should compare the device IDs the driver supports with the | |
56 | * device IDs of the device. Note we don't do this ourselves | |
57 | * because we don't know the format of the ID structures, nor what | |
58 | * is to be considered a match and what is not. | |
59 | * | |
60 | * If we find a match, we call @drv->probe(@dev) if it exists, and | |
61 | * call device_bind_driver() above. | |
62 | */ | |
63 | int driver_probe_device(struct device_driver * drv, struct device * dev) | |
64 | { | |
65 | int error = 0; | |
66 | ||
67 | if (drv->bus->match && !drv->bus->match(dev, drv)) | |
68 | return -ENODEV; | |
69 | ||
70 | down(&dev->sem); | |
71 | dev->driver = drv; | |
72 | if (drv->probe) { | |
73 | error = drv->probe(dev); | |
74 | if (error) { | |
75 | dev->driver = NULL; | |
76 | up(&dev->sem); | |
77 | return error; | |
78 | } | |
79 | } | |
80 | up(&dev->sem); | |
81 | device_bind_driver(dev); | |
82 | return 0; | |
83 | } | |
84 | ||
85 | /** | |
86 | * device_attach - try to attach device to a driver. | |
87 | * @dev: device. | |
88 | * | |
89 | * Walk the list of drivers that the bus has and call | |
90 | * driver_probe_device() for each pair. If a compatible | |
91 | * pair is found, break out and return. | |
92 | */ | |
93 | int device_attach(struct device * dev) | |
94 | { | |
95 | struct bus_type * bus = dev->bus; | |
96 | struct list_head * entry; | |
97 | int error; | |
98 | ||
99 | if (dev->driver) { | |
100 | device_bind_driver(dev); | |
101 | return 1; | |
102 | } | |
103 | ||
104 | if (bus->match) { | |
105 | list_for_each(entry, &bus->drivers.list) { | |
106 | struct device_driver * drv = to_drv(entry); | |
107 | error = driver_probe_device(drv, dev); | |
108 | if (!error) | |
109 | /* success, driver matched */ | |
110 | return 1; | |
111 | if (error != -ENODEV && error != -ENXIO) | |
112 | /* driver matched but the probe failed */ | |
113 | printk(KERN_WARNING | |
114 | "%s: probe of %s failed with error %d\n", | |
115 | drv->name, dev->bus_id, error); | |
116 | } | |
117 | } | |
118 | ||
119 | return 0; | |
120 | } | |
121 | ||
122 | /** | |
123 | * driver_attach - try to bind driver to devices. | |
124 | * @drv: driver. | |
125 | * | |
126 | * Walk the list of devices that the bus has on it and try to | |
127 | * match the driver with each one. If driver_probe_device() | |
128 | * returns 0 and the @dev->driver is set, we've found a | |
129 | * compatible pair. | |
130 | * | |
131 | * Note that we ignore the -ENODEV error from driver_probe_device(), | |
132 | * since it's perfectly valid for a driver not to bind to any devices. | |
133 | */ | |
134 | void driver_attach(struct device_driver * drv) | |
135 | { | |
136 | struct bus_type * bus = drv->bus; | |
137 | struct list_head * entry; | |
138 | int error; | |
139 | ||
140 | if (!bus->match) | |
141 | return; | |
142 | ||
143 | list_for_each(entry, &bus->devices.list) { | |
144 | struct device * dev = container_of(entry, struct device, bus_list); | |
145 | if (!dev->driver) { | |
146 | error = driver_probe_device(drv, dev); | |
147 | if (error && (error != -ENODEV)) | |
148 | /* driver matched but the probe failed */ | |
149 | printk(KERN_WARNING | |
150 | "%s: probe of %s failed with error %d\n", | |
151 | drv->name, dev->bus_id, error); | |
152 | } | |
153 | } | |
154 | } | |
155 | ||
156 | /** | |
157 | * device_release_driver - manually detach device from driver. | |
158 | * @dev: device. | |
159 | * | |
160 | * Manually detach device from driver. | |
161 | * Note that this is called without incrementing the bus | |
162 | * reference count nor taking the bus's rwsem. Be sure that | |
163 | * those are accounted for before calling this function. | |
164 | */ | |
165 | void device_release_driver(struct device * dev) | |
166 | { | |
167 | struct device_driver * drv; | |
168 | ||
169 | down(&dev->sem); | |
170 | drv = dev->driver; | |
171 | if (drv) { | |
172 | sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj)); | |
173 | sysfs_remove_link(&dev->kobj, "driver"); | |
174 | list_del_init(&dev->driver_list); | |
175 | if (drv->remove) | |
176 | drv->remove(dev); | |
177 | dev->driver = NULL; | |
178 | } | |
179 | up(&dev->sem); | |
180 | } | |
181 | ||
182 | /** | |
183 | * driver_detach - detach driver from all devices it controls. | |
184 | * @drv: driver. | |
185 | */ | |
186 | void driver_detach(struct device_driver * drv) | |
187 | { | |
188 | while (!list_empty(&drv->devices)) { | |
189 | struct device * dev = container_of(drv->devices.next, struct device, driver_list); | |
190 | device_release_driver(dev); | |
191 | } | |
192 | } | |
193 | ||
194 | ||
195 | EXPORT_SYMBOL_GPL(driver_probe_device); | |
196 | EXPORT_SYMBOL_GPL(device_bind_driver); | |
197 | EXPORT_SYMBOL_GPL(device_release_driver); | |
198 | EXPORT_SYMBOL_GPL(device_attach); | |
199 | EXPORT_SYMBOL_GPL(driver_attach); | |
200 |