Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[muen/linux.git] / sound / core / device.c
1 /*
2  *  Device management routines
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21
22 #include <linux/slab.h>
23 #include <linux/time.h>
24 #include <linux/export.h>
25 #include <linux/errno.h>
26 #include <sound/core.h>
27
28 /**
29  * snd_device_new - create an ALSA device component
30  * @card: the card instance
31  * @type: the device type, SNDRV_DEV_XXX
32  * @device_data: the data pointer of this device
33  * @ops: the operator table
34  *
35  * Creates a new device component for the given data pointer.
36  * The device will be assigned to the card and managed together
37  * by the card.
38  *
39  * The data pointer plays a role as the identifier, too, so the
40  * pointer address must be unique and unchanged.
41  *
42  * Return: Zero if successful, or a negative error code on failure.
43  */
44 int snd_device_new(struct snd_card *card, enum snd_device_type type,
45                    void *device_data, struct snd_device_ops *ops)
46 {
47         struct snd_device *dev;
48         struct list_head *p;
49
50         if (snd_BUG_ON(!card || !device_data || !ops))
51                 return -ENXIO;
52         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
53         if (!dev)
54                 return -ENOMEM;
55         INIT_LIST_HEAD(&dev->list);
56         dev->card = card;
57         dev->type = type;
58         dev->state = SNDRV_DEV_BUILD;
59         dev->device_data = device_data;
60         dev->ops = ops;
61
62         /* insert the entry in an incrementally sorted list */
63         list_for_each_prev(p, &card->devices) {
64                 struct snd_device *pdev = list_entry(p, struct snd_device, list);
65                 if ((unsigned int)pdev->type <= (unsigned int)type)
66                         break;
67         }
68
69         list_add(&dev->list, p);
70         return 0;
71 }
72 EXPORT_SYMBOL(snd_device_new);
73
74 static void __snd_device_disconnect(struct snd_device *dev)
75 {
76         if (dev->state == SNDRV_DEV_REGISTERED) {
77                 if (dev->ops->dev_disconnect &&
78                     dev->ops->dev_disconnect(dev))
79                         dev_err(dev->card->dev, "device disconnect failure\n");
80                 dev->state = SNDRV_DEV_DISCONNECTED;
81         }
82 }
83
84 static void __snd_device_free(struct snd_device *dev)
85 {
86         /* unlink */
87         list_del(&dev->list);
88
89         __snd_device_disconnect(dev);
90         if (dev->ops->dev_free) {
91                 if (dev->ops->dev_free(dev))
92                         dev_err(dev->card->dev, "device free failure\n");
93         }
94         kfree(dev);
95 }
96
97 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
98 {
99         struct snd_device *dev;
100
101         list_for_each_entry(dev, &card->devices, list)
102                 if (dev->device_data == device_data)
103                         return dev;
104
105         return NULL;
106 }
107
108 /**
109  * snd_device_disconnect - disconnect the device
110  * @card: the card instance
111  * @device_data: the data pointer to disconnect
112  *
113  * Turns the device into the disconnection state, invoking
114  * dev_disconnect callback, if the device was already registered.
115  *
116  * Usually called from snd_card_disconnect().
117  *
118  * Return: Zero if successful, or a negative error code on failure or if the
119  * device not found.
120  */
121 void snd_device_disconnect(struct snd_card *card, void *device_data)
122 {
123         struct snd_device *dev;
124
125         if (snd_BUG_ON(!card || !device_data))
126                 return;
127         dev = look_for_dev(card, device_data);
128         if (dev)
129                 __snd_device_disconnect(dev);
130         else
131                 dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
132                         device_data, __builtin_return_address(0));
133 }
134 EXPORT_SYMBOL_GPL(snd_device_disconnect);
135
136 /**
137  * snd_device_free - release the device from the card
138  * @card: the card instance
139  * @device_data: the data pointer to release
140  *
141  * Removes the device from the list on the card and invokes the
142  * callbacks, dev_disconnect and dev_free, corresponding to the state.
143  * Then release the device.
144  */
145 void snd_device_free(struct snd_card *card, void *device_data)
146 {
147         struct snd_device *dev;
148         
149         if (snd_BUG_ON(!card || !device_data))
150                 return;
151         dev = look_for_dev(card, device_data);
152         if (dev)
153                 __snd_device_free(dev);
154         else
155                 dev_dbg(card->dev, "device free %p (from %pF), not found\n",
156                         device_data, __builtin_return_address(0));
157 }
158 EXPORT_SYMBOL(snd_device_free);
159
160 static int __snd_device_register(struct snd_device *dev)
161 {
162         if (dev->state == SNDRV_DEV_BUILD) {
163                 if (dev->ops->dev_register) {
164                         int err = dev->ops->dev_register(dev);
165                         if (err < 0)
166                                 return err;
167                 }
168                 dev->state = SNDRV_DEV_REGISTERED;
169         }
170         return 0;
171 }
172
173 /**
174  * snd_device_register - register the device
175  * @card: the card instance
176  * @device_data: the data pointer to register
177  *
178  * Registers the device which was already created via
179  * snd_device_new().  Usually this is called from snd_card_register(),
180  * but it can be called later if any new devices are created after
181  * invocation of snd_card_register().
182  *
183  * Return: Zero if successful, or a negative error code on failure or if the
184  * device not found.
185  */
186 int snd_device_register(struct snd_card *card, void *device_data)
187 {
188         struct snd_device *dev;
189
190         if (snd_BUG_ON(!card || !device_data))
191                 return -ENXIO;
192         dev = look_for_dev(card, device_data);
193         if (dev)
194                 return __snd_device_register(dev);
195         snd_BUG();
196         return -ENXIO;
197 }
198 EXPORT_SYMBOL(snd_device_register);
199
200 /*
201  * register all the devices on the card.
202  * called from init.c
203  */
204 int snd_device_register_all(struct snd_card *card)
205 {
206         struct snd_device *dev;
207         int err;
208         
209         if (snd_BUG_ON(!card))
210                 return -ENXIO;
211         list_for_each_entry(dev, &card->devices, list) {
212                 err = __snd_device_register(dev);
213                 if (err < 0)
214                         return err;
215         }
216         return 0;
217 }
218
219 /*
220  * disconnect all the devices on the card.
221  * called from init.c
222  */
223 void snd_device_disconnect_all(struct snd_card *card)
224 {
225         struct snd_device *dev;
226
227         if (snd_BUG_ON(!card))
228                 return;
229         list_for_each_entry_reverse(dev, &card->devices, list)
230                 __snd_device_disconnect(dev);
231 }
232
233 /*
234  * release all the devices on the card.
235  * called from init.c
236  */
237 void snd_device_free_all(struct snd_card *card)
238 {
239         struct snd_device *dev, *next;
240
241         if (snd_BUG_ON(!card))
242                 return;
243         list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
244                 __snd_device_free(dev);
245 }