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mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -08001/*
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.)
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070038 *
39 * This function must be called with @dev->sem held.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080040 */
41void device_bind_driver(struct device * dev)
42{
Daniel Ritz4c898c72005-09-22 00:47:11 -070043 if (klist_node_attached(&dev->knode_driver))
44 return;
45
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080046 pr_debug("bound device '%s' to driver '%s'\n",
47 dev->bus_id, dev->driver->name);
James Bottomleyd856f1e32005-08-19 09:14:01 -040048 klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080049 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 *
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070065 * 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 *
Alan Sternbf74ad52005-11-17 16:54:12 -050068 * This function must be called with @dev->sem held. When called
69 * for a USB interface, @dev->parent->sem must be held as well.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080070 */
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -070071int driver_probe_device(struct device_driver * drv, struct device * dev)
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080072{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070073 int ret = 0;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080074
75 if (drv->bus->match && !drv->bus->match(dev, drv))
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070076 goto Done;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080077
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070078 pr_debug("%s: Matched Device %s with Driver %s\n",
79 drv->bus->name, dev->bus_id, drv->name);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080080 dev->driver = drv;
Russell King594c8282006-01-05 14:29:51 +000081 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) {
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070088 ret = drv->probe(dev);
89 if (ret) {
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080090 dev->driver = NULL;
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070091 goto ProbeFailed;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080092 }
93 }
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080094 device_bind_driver(dev);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070095 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;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800115}
116
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800117static int __device_attach(struct device_driver * drv, void * data)
118{
119 struct device * dev = data;
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700120 return driver_probe_device(drv, dev);
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800121}
122
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800123/**
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.
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700130 *
Hannes Reineckeca2b94b2005-05-18 10:42:23 +0200131 * Returns 1 if the device was bound to a driver;
132 * 0 if no matching device was found; error code otherwise.
Alan Sternbf74ad52005-11-17 16:54:12 -0500133 *
134 * When called for a USB interface, @dev->parent->sem must be held.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800135 */
136int device_attach(struct device * dev)
137{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700138 int ret = 0;
139
140 down(&dev->sem);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800141 if (dev->driver) {
142 device_bind_driver(dev);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700143 ret = 1;
144 } else
145 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
146 up(&dev->sem);
147 return ret;
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800148}
149
150static int __driver_attach(struct device * dev, void * data)
151{
152 struct device_driver * drv = data;
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800153
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700154 /*
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
Alan Sternbf74ad52005-11-17 16:54:12 -0500164 if (dev->parent) /* Needed for USB */
165 down(&dev->parent->sem);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700166 down(&dev->sem);
167 if (!dev->driver)
168 driver_probe_device(drv, dev);
169 up(&dev->sem);
Alan Sternbf74ad52005-11-17 16:54:12 -0500170 if (dev->parent)
171 up(&dev->parent->sem);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700172
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800173 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.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800184 */
185void driver_attach(struct device_driver * drv)
186{
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800187 bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800188}
189
190/**
191 * device_release_driver - manually detach device from driver.
192 * @dev: device.
193 *
194 * Manually detach device from driver.
Alan Sternc95a6b02005-05-06 15:38:33 -0400195 *
196 * __device_release_driver() must be called with @dev->sem held.
Alan Sternbf74ad52005-11-17 16:54:12 -0500197 * When called for a USB interface, @dev->parent->sem must be held
198 * as well.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800199 */
Alan Sternc95a6b02005-05-06 15:38:33 -0400200
201static void __device_release_driver(struct device * dev)
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800202{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700203 struct device_driver * drv;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800204
Alan Sternc95a6b02005-05-06 15:38:33 -0400205 drv = dev->driver;
206 if (drv) {
207 get_driver(drv);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700208 sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
209 sysfs_remove_link(&dev->kobj, "driver");
Alan Sternc95a6b02005-05-06 15:38:33 -0400210 klist_remove(&dev->knode_driver);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700211
Alan Stern0f836ca2006-03-31 11:52:25 -0500212 if (dev->bus && dev->bus->remove)
Russell King594c8282006-01-05 14:29:51 +0000213 dev->bus->remove(dev);
214 else if (drv->remove)
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700215 drv->remove(dev);
216 dev->driver = NULL;
Alan Sternc95a6b02005-05-06 15:38:33 -0400217 put_driver(drv);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700218 }
Alan Sternc95a6b02005-05-06 15:38:33 -0400219}
220
221void device_release_driver(struct device * dev)
222{
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);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800230 up(&dev->sem);
231}
232
mochel@digitalimplant.org94e7b1c52005-03-21 12:25:36 -0800233
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800234/**
235 * driver_detach - detach driver from all devices it controls.
236 * @drv: driver.
237 */
238void driver_detach(struct device_driver * drv)
239{
Alan Sternc95a6b02005-05-06 15:38:33 -0400240 struct device * dev;
241
242 for (;;) {
Alan Stern2b08c8d2005-11-23 15:43:50 -0800243 spin_lock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400244 if (list_empty(&drv->klist_devices.k_list)) {
Alan Stern2b08c8d2005-11-23 15:43:50 -0800245 spin_unlock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400246 break;
247 }
248 dev = list_entry(drv->klist_devices.k_list.prev,
249 struct device, knode_driver.n_node);
250 get_device(dev);
Alan Stern2b08c8d2005-11-23 15:43:50 -0800251 spin_unlock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400252
Alan Sternbf74ad52005-11-17 16:54:12 -0500253 if (dev->parent) /* Needed for USB */
254 down(&dev->parent->sem);
Alan Sternc95a6b02005-05-06 15:38:33 -0400255 down(&dev->sem);
256 if (dev->driver == drv)
257 __device_release_driver(dev);
258 up(&dev->sem);
Alan Sternbf74ad52005-11-17 16:54:12 -0500259 if (dev->parent)
260 up(&dev->parent->sem);
Alan Sternc95a6b02005-05-06 15:38:33 -0400261 put_device(dev);
262 }
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800263}
264
265
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800266EXPORT_SYMBOL_GPL(device_bind_driver);
267EXPORT_SYMBOL_GPL(device_release_driver);
268EXPORT_SYMBOL_GPL(device_attach);
269EXPORT_SYMBOL_GPL(driver_attach);
270