xref: /openbmc/linux/sound/core/device.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  Device management routines
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
23 #include <linux/slab.h>
24 #include <linux/time.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  * Returns zero if successful, or a negative error code on failure.
43  */
44 int snd_device_new(snd_card_t *card, snd_device_type_t type,
45 		   void *device_data, snd_device_ops_t *ops)
46 {
47 	snd_device_t *dev;
48 
49 	snd_assert(card != NULL, return -ENXIO);
50 	snd_assert(device_data != NULL, return -ENXIO);
51 	snd_assert(ops != NULL, return -ENXIO);
52 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
53 	if (dev == NULL)
54 		return -ENOMEM;
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 
64 /**
65  * snd_device_free - release the device from the card
66  * @card: the card instance
67  * @device_data: the data pointer to release
68  *
69  * Removes the device from the list on the card and invokes the
70  * callback, dev_unregister or dev_free, corresponding to the state.
71  * Then release the device.
72  *
73  * Returns zero if successful, or a negative error code on failure or if the
74  * device not found.
75  */
76 int snd_device_free(snd_card_t *card, void *device_data)
77 {
78 	struct list_head *list;
79 	snd_device_t *dev;
80 
81 	snd_assert(card != NULL, return -ENXIO);
82 	snd_assert(device_data != NULL, return -ENXIO);
83 	list_for_each(list, &card->devices) {
84 		dev = snd_device(list);
85 		if (dev->device_data != device_data)
86 			continue;
87 		/* unlink */
88 		list_del(&dev->list);
89 		if ((dev->state == SNDRV_DEV_REGISTERED || dev->state == SNDRV_DEV_DISCONNECTED) &&
90 		    dev->ops->dev_unregister) {
91 			if (dev->ops->dev_unregister(dev))
92 				snd_printk(KERN_ERR "device unregister failure\n");
93 		} else {
94 			if (dev->ops->dev_free) {
95 				if (dev->ops->dev_free(dev))
96 					snd_printk(KERN_ERR "device free failure\n");
97 			}
98 		}
99 		kfree(dev);
100 		return 0;
101 	}
102 	snd_printd("device free %p (from %p), not found\n", device_data, __builtin_return_address(0));
103 	return -ENXIO;
104 }
105 
106 /**
107  * snd_device_disconnect - disconnect the device
108  * @card: the card instance
109  * @device_data: the data pointer to disconnect
110  *
111  * Turns the device into the disconnection state, invoking
112  * dev_disconnect callback, if the device was already registered.
113  *
114  * Usually called from snd_card_disconnect().
115  *
116  * Returns zero if successful, or a negative error code on failure or if the
117  * device not found.
118  */
119 int snd_device_disconnect(snd_card_t *card, void *device_data)
120 {
121 	struct list_head *list;
122 	snd_device_t *dev;
123 
124 	snd_assert(card != NULL, return -ENXIO);
125 	snd_assert(device_data != NULL, return -ENXIO);
126 	list_for_each(list, &card->devices) {
127 		dev = snd_device(list);
128 		if (dev->device_data != device_data)
129 			continue;
130 		if (dev->state == SNDRV_DEV_REGISTERED && dev->ops->dev_disconnect) {
131 			if (dev->ops->dev_disconnect(dev))
132 				snd_printk(KERN_ERR "device disconnect failure\n");
133 			dev->state = SNDRV_DEV_DISCONNECTED;
134 		}
135 		return 0;
136 	}
137 	snd_printd("device disconnect %p (from %p), not found\n", device_data, __builtin_return_address(0));
138 	return -ENXIO;
139 }
140 
141 /**
142  * snd_device_register - register the device
143  * @card: the card instance
144  * @device_data: the data pointer to register
145  *
146  * Registers the device which was already created via
147  * snd_device_new().  Usually this is called from snd_card_register(),
148  * but it can be called later if any new devices are created after
149  * invocation of snd_card_register().
150  *
151  * Returns zero if successful, or a negative error code on failure or if the
152  * device not found.
153  */
154 int snd_device_register(snd_card_t *card, void *device_data)
155 {
156 	struct list_head *list;
157 	snd_device_t *dev;
158 	int err;
159 
160 	snd_assert(card != NULL, return -ENXIO);
161 	snd_assert(device_data != NULL, return -ENXIO);
162 	list_for_each(list, &card->devices) {
163 		dev = snd_device(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 		return -EBUSY;
173 	}
174 	snd_BUG();
175 	return -ENXIO;
176 }
177 
178 /*
179  * register all the devices on the card.
180  * called from init.c
181  */
182 int snd_device_register_all(snd_card_t *card)
183 {
184 	struct list_head *list;
185 	snd_device_t *dev;
186 	int err;
187 
188 	snd_assert(card != NULL, return -ENXIO);
189 	list_for_each(list, &card->devices) {
190 		dev = snd_device(list);
191 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
192 			if ((err = dev->ops->dev_register(dev)) < 0)
193 				return err;
194 			dev->state = SNDRV_DEV_REGISTERED;
195 		}
196 	}
197 	return 0;
198 }
199 
200 /*
201  * disconnect all the devices on the card.
202  * called from init.c
203  */
204 int snd_device_disconnect_all(snd_card_t *card)
205 {
206 	snd_device_t *dev;
207 	struct list_head *list;
208 	int err = 0;
209 
210 	snd_assert(card != NULL, return -ENXIO);
211 	list_for_each(list, &card->devices) {
212 		dev = snd_device(list);
213 		if (snd_device_disconnect(card, dev->device_data) < 0)
214 			err = -ENXIO;
215 	}
216 	return err;
217 }
218 
219 /*
220  * release all the devices on the card.
221  * called from init.c
222  */
223 int snd_device_free_all(snd_card_t *card, snd_device_cmd_t cmd)
224 {
225 	snd_device_t *dev;
226 	struct list_head *list;
227 	int err;
228 	unsigned int range_low, range_high;
229 
230 	snd_assert(card != NULL, return -ENXIO);
231 	range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
232 	range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
233       __again:
234 	list_for_each(list, &card->devices) {
235 		dev = snd_device(list);
236 		if (dev->type >= range_low && dev->type <= range_high) {
237 			if ((err = snd_device_free(card, dev->device_data)) < 0)
238 				return err;
239 			goto __again;
240 		}
241 	}
242 	return 0;
243 }
244