Root/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/errno.h>
25#include <sound/core.h>
26
27/**
28 * snd_device_new - create an ALSA device component
29 * @card: the card instance
30 * @type: the device type, SNDRV_DEV_XXX
31 * @device_data: the data pointer of this device
32 * @ops: the operator table
33 *
34 * Creates a new device component for the given data pointer.
35 * The device will be assigned to the card and managed together
36 * by the card.
37 *
38 * The data pointer plays a role as the identifier, too, so the
39 * pointer address must be unique and unchanged.
40 *
41 * Returns zero if successful, or a negative error code on failure.
42 */
43int snd_device_new(struct snd_card *card, snd_device_type_t type,
44           void *device_data, struct snd_device_ops *ops)
45{
46    struct snd_device *dev;
47
48    if (snd_BUG_ON(!card || !device_data || !ops))
49        return -ENXIO;
50    dev = kzalloc(sizeof(*dev), GFP_KERNEL);
51    if (dev == NULL) {
52        snd_printk(KERN_ERR "Cannot allocate device\n");
53        return -ENOMEM;
54    }
55    dev->card = card;
56    dev->type = type;
57    dev->state = SNDRV_DEV_BUILD;
58    dev->device_data = device_data;
59    dev->ops = ops;
60    list_add(&dev->list, &card->devices); /* add to the head of list */
61    return 0;
62}
63
64EXPORT_SYMBOL(snd_device_new);
65
66/**
67 * snd_device_free - release the device from the card
68 * @card: the card instance
69 * @device_data: the data pointer to release
70 *
71 * Removes the device from the list on the card and invokes the
72 * callbacks, dev_disconnect and dev_free, corresponding to the state.
73 * Then release the device.
74 *
75 * Returns zero if successful, or a negative error code on failure or if the
76 * device not found.
77 */
78int snd_device_free(struct snd_card *card, void *device_data)
79{
80    struct snd_device *dev;
81    
82    if (snd_BUG_ON(!card || !device_data))
83        return -ENXIO;
84    list_for_each_entry(dev, &card->devices, list) {
85        if (dev->device_data != device_data)
86            continue;
87        /* unlink */
88        list_del(&dev->list);
89        if (dev->state == SNDRV_DEV_REGISTERED &&
90            dev->ops->dev_disconnect)
91            if (dev->ops->dev_disconnect(dev))
92                snd_printk(KERN_ERR
93                       "device disconnect failure\n");
94        if (dev->ops->dev_free) {
95            if (dev->ops->dev_free(dev))
96                snd_printk(KERN_ERR "device free failure\n");
97        }
98        kfree(dev);
99        return 0;
100    }
101    snd_printd("device free %p (from %pF), not found\n", device_data,
102           __builtin_return_address(0));
103    return -ENXIO;
104}
105
106EXPORT_SYMBOL(snd_device_free);
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 * Returns zero if successful, or a negative error code on failure or if the
119 * device not found.
120 */
121int 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 -ENXIO;
127    list_for_each_entry(dev, &card->devices, list) {
128        if (dev->device_data != device_data)
129            continue;
130        if (dev->state == SNDRV_DEV_REGISTERED &&
131            dev->ops->dev_disconnect) {
132            if (dev->ops->dev_disconnect(dev))
133                snd_printk(KERN_ERR "device disconnect failure\n");
134            dev->state = SNDRV_DEV_DISCONNECTED;
135        }
136        return 0;
137    }
138    snd_printd("device disconnect %p (from %pF), not found\n", device_data,
139           __builtin_return_address(0));
140    return -ENXIO;
141}
142
143/**
144 * snd_device_register - register the device
145 * @card: the card instance
146 * @device_data: the data pointer to register
147 *
148 * Registers the device which was already created via
149 * snd_device_new(). Usually this is called from snd_card_register(),
150 * but it can be called later if any new devices are created after
151 * invocation of snd_card_register().
152 *
153 * Returns zero if successful, or a negative error code on failure or if the
154 * device not found.
155 */
156int snd_device_register(struct snd_card *card, void *device_data)
157{
158    struct snd_device *dev;
159    int err;
160
161    if (snd_BUG_ON(!card || !device_data))
162        return -ENXIO;
163    list_for_each_entry(dev, &card->devices, list) {
164        if (dev->device_data != device_data)
165            continue;
166        if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
167            if ((err = dev->ops->dev_register(dev)) < 0)
168                return err;
169            dev->state = SNDRV_DEV_REGISTERED;
170            return 0;
171        }
172        snd_printd("snd_device_register busy\n");
173        return -EBUSY;
174    }
175    snd_BUG();
176    return -ENXIO;
177}
178
179EXPORT_SYMBOL(snd_device_register);
180
181/*
182 * register all the devices on the card.
183 * called from init.c
184 */
185int snd_device_register_all(struct snd_card *card)
186{
187    struct snd_device *dev;
188    int err;
189    
190    if (snd_BUG_ON(!card))
191        return -ENXIO;
192    list_for_each_entry(dev, &card->devices, list) {
193        if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
194            if ((err = dev->ops->dev_register(dev)) < 0)
195                return err;
196            dev->state = SNDRV_DEV_REGISTERED;
197        }
198    }
199    return 0;
200}
201
202/*
203 * disconnect all the devices on the card.
204 * called from init.c
205 */
206int snd_device_disconnect_all(struct snd_card *card)
207{
208    struct snd_device *dev;
209    int err = 0;
210
211    if (snd_BUG_ON(!card))
212        return -ENXIO;
213    list_for_each_entry(dev, &card->devices, list) {
214        if (snd_device_disconnect(card, dev->device_data) < 0)
215            err = -ENXIO;
216    }
217    return err;
218}
219
220/*
221 * release all the devices on the card.
222 * called from init.c
223 */
224int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
225{
226    struct snd_device *dev;
227    int err;
228    unsigned int range_low, range_high, type;
229
230    if (snd_BUG_ON(!card))
231        return -ENXIO;
232    range_low = (__force unsigned int)cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
233    range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
234      __again:
235    list_for_each_entry(dev, &card->devices, list) {
236        type = (__force unsigned int)dev->type;
237        if (type >= range_low && type <= range_high) {
238            if ((err = snd_device_free(card, dev->device_data)) < 0)
239                return err;
240            goto __again;
241        }
242    }
243    return 0;
244}
245

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