blob: 3b419c9a1e7e6d407a8b3a5ad26440534c499a7b [file] [log] [blame]
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 *
68 * This function must be called with @dev->sem held.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080069 */
Greg Kroah-Hartmanafdce752005-06-22 16:09:05 -070070int driver_probe_device(struct device_driver * drv, struct device * dev)
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080071{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070072 int ret = 0;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080073
74 if (drv->bus->match && !drv->bus->match(dev, drv))
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070075 goto Done;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080076
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070077 pr_debug("%s: Matched Device %s with Driver %s\n",
78 drv->bus->name, dev->bus_id, drv->name);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080079 dev->driver = drv;
80 if (drv->probe) {
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070081 ret = drv->probe(dev);
82 if (ret) {
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080083 dev->driver = NULL;
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070084 goto ProbeFailed;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080085 }
86 }
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -080087 device_bind_driver(dev);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -070088 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;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800108}
109
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800110static int __device_attach(struct device_driver * drv, void * data)
111{
112 struct device * dev = data;
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700113 return driver_probe_device(drv, dev);
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800114}
115
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800116/**
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.
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700123 *
Hannes Reineckeca2b94b2005-05-18 10:42:23 +0200124 * Returns 1 if the device was bound to a driver;
125 * 0 if no matching device was found; error code otherwise.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800126 */
127int device_attach(struct device * dev)
128{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700129 int ret = 0;
130
131 down(&dev->sem);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800132 if (dev->driver) {
133 device_bind_driver(dev);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700134 ret = 1;
135 } else
136 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
137 up(&dev->sem);
138 return ret;
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800139}
140
141static int __driver_attach(struct device * dev, void * data)
142{
143 struct device_driver * drv = data;
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800144
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700145 /*
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
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800160 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.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800171 */
172void driver_attach(struct device_driver * drv)
173{
mochel@digitalimplant.org2287c322005-03-24 10:50:24 -0800174 bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800175}
176
177/**
178 * device_release_driver - manually detach device from driver.
179 * @dev: device.
180 *
181 * Manually detach device from driver.
Alan Sternc95a6b02005-05-06 15:38:33 -0400182 *
183 * __device_release_driver() must be called with @dev->sem held.
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800184 */
Alan Sternc95a6b02005-05-06 15:38:33 -0400185
186static void __device_release_driver(struct device * dev)
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800187{
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700188 struct device_driver * drv;
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800189
Alan Sternc95a6b02005-05-06 15:38:33 -0400190 drv = dev->driver;
191 if (drv) {
192 get_driver(drv);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700193 sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
194 sysfs_remove_link(&dev->kobj, "driver");
Alan Sternc95a6b02005-05-06 15:38:33 -0400195 klist_remove(&dev->knode_driver);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700196
197 if (drv->remove)
198 drv->remove(dev);
199 dev->driver = NULL;
Alan Sternc95a6b02005-05-06 15:38:33 -0400200 put_driver(drv);
Patrick Mochel0d3e5a22005-04-05 23:46:33 -0700201 }
Alan Sternc95a6b02005-05-06 15:38:33 -0400202}
203
204void device_release_driver(struct device * dev)
205{
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);
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800213 up(&dev->sem);
214}
215
mochel@digitalimplant.org94e7b1c52005-03-21 12:25:36 -0800216
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800217/**
218 * driver_detach - detach driver from all devices it controls.
219 * @drv: driver.
220 */
221void driver_detach(struct device_driver * drv)
222{
Alan Sternc95a6b02005-05-06 15:38:33 -0400223 struct device * dev;
224
225 for (;;) {
Alan Stern2b08c8d2005-11-23 15:43:50 -0800226 spin_lock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400227 if (list_empty(&drv->klist_devices.k_list)) {
Alan Stern2b08c8d2005-11-23 15:43:50 -0800228 spin_unlock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400229 break;
230 }
231 dev = list_entry(drv->klist_devices.k_list.prev,
232 struct device, knode_driver.n_node);
233 get_device(dev);
Alan Stern2b08c8d2005-11-23 15:43:50 -0800234 spin_unlock(&drv->klist_devices.k_lock);
Alan Sternc95a6b02005-05-06 15:38:33 -0400235
236 down(&dev->sem);
237 if (dev->driver == drv)
238 __device_release_driver(dev);
239 up(&dev->sem);
240 put_device(dev);
241 }
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800242}
243
244
mochel@digitalimplant.org07e4a3e2005-03-21 10:52:54 -0800245EXPORT_SYMBOL_GPL(device_bind_driver);
246EXPORT_SYMBOL_GPL(device_release_driver);
247EXPORT_SYMBOL_GPL(device_attach);
248EXPORT_SYMBOL_GPL(driver_attach);
249