xref: /openbmc/linux/sound/core/device.c (revision a1e58bbd)
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  */
43 int 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 	snd_assert(card != NULL, return -ENXIO);
49 	snd_assert(device_data != NULL, return -ENXIO);
50 	snd_assert(ops != NULL, return -ENXIO);
51 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
52 	if (dev == NULL) {
53 		snd_printk(KERN_ERR "Cannot allocate device\n");
54 		return -ENOMEM;
55 	}
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 	list_add(&dev->list, &card->devices);	/* add to the head of list */
62 	return 0;
63 }
64 
65 EXPORT_SYMBOL(snd_device_new);
66 
67 /**
68  * snd_device_free - release the device from the card
69  * @card: the card instance
70  * @device_data: the data pointer to release
71  *
72  * Removes the device from the list on the card and invokes the
73  * callbacks, dev_disconnect and dev_free, corresponding to the state.
74  * Then release the device.
75  *
76  * Returns zero if successful, or a negative error code on failure or if the
77  * device not found.
78  */
79 int snd_device_free(struct snd_card *card, void *device_data)
80 {
81 	struct snd_device *dev;
82 
83 	snd_assert(card != NULL, return -ENXIO);
84 	snd_assert(device_data != NULL, return -ENXIO);
85 	list_for_each_entry(dev, &card->devices, list) {
86 		if (dev->device_data != device_data)
87 			continue;
88 		/* unlink */
89 		list_del(&dev->list);
90 		if (dev->state == SNDRV_DEV_REGISTERED &&
91 		    dev->ops->dev_disconnect)
92 			if (dev->ops->dev_disconnect(dev))
93 				snd_printk(KERN_ERR
94 					   "device disconnect failure\n");
95 		if (dev->ops->dev_free) {
96 			if (dev->ops->dev_free(dev))
97 				snd_printk(KERN_ERR "device free failure\n");
98 		}
99 		kfree(dev);
100 		return 0;
101 	}
102 	snd_printd("device free %p (from %p), not found\n", device_data,
103 		   __builtin_return_address(0));
104 	return -ENXIO;
105 }
106 
107 EXPORT_SYMBOL(snd_device_free);
108 
109 /**
110  * snd_device_disconnect - disconnect the device
111  * @card: the card instance
112  * @device_data: the data pointer to disconnect
113  *
114  * Turns the device into the disconnection state, invoking
115  * dev_disconnect callback, if the device was already registered.
116  *
117  * Usually called from snd_card_disconnect().
118  *
119  * Returns zero if successful, or a negative error code on failure or if the
120  * device not found.
121  */
122 int snd_device_disconnect(struct snd_card *card, void *device_data)
123 {
124 	struct snd_device *dev;
125 
126 	snd_assert(card != NULL, return -ENXIO);
127 	snd_assert(device_data != NULL, return -ENXIO);
128 	list_for_each_entry(dev, &card->devices, list) {
129 		if (dev->device_data != device_data)
130 			continue;
131 		if (dev->state == SNDRV_DEV_REGISTERED &&
132 		    dev->ops->dev_disconnect) {
133 			if (dev->ops->dev_disconnect(dev))
134 				snd_printk(KERN_ERR "device disconnect failure\n");
135 			dev->state = SNDRV_DEV_DISCONNECTED;
136 		}
137 		return 0;
138 	}
139 	snd_printd("device disconnect %p (from %p), not found\n", device_data,
140 		   __builtin_return_address(0));
141 	return -ENXIO;
142 }
143 
144 /**
145  * snd_device_register - register the device
146  * @card: the card instance
147  * @device_data: the data pointer to register
148  *
149  * Registers the device which was already created via
150  * snd_device_new().  Usually this is called from snd_card_register(),
151  * but it can be called later if any new devices are created after
152  * invocation of snd_card_register().
153  *
154  * Returns zero if successful, or a negative error code on failure or if the
155  * device not found.
156  */
157 int snd_device_register(struct snd_card *card, void *device_data)
158 {
159 	struct snd_device *dev;
160 	int err;
161 
162 	snd_assert(card != NULL, return -ENXIO);
163 	snd_assert(device_data != NULL, return -ENXIO);
164 	list_for_each_entry(dev, &card->devices, list) {
165 		if (dev->device_data != device_data)
166 			continue;
167 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
168 			if ((err = dev->ops->dev_register(dev)) < 0)
169 				return err;
170 			dev->state = SNDRV_DEV_REGISTERED;
171 			return 0;
172 		}
173 		snd_printd("snd_device_register busy\n");
174 		return -EBUSY;
175 	}
176 	snd_BUG();
177 	return -ENXIO;
178 }
179 
180 EXPORT_SYMBOL(snd_device_register);
181 
182 /*
183  * register all the devices on the card.
184  * called from init.c
185  */
186 int snd_device_register_all(struct snd_card *card)
187 {
188 	struct snd_device *dev;
189 	int err;
190 
191 	snd_assert(card != NULL, 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  */
206 int snd_device_disconnect_all(struct snd_card *card)
207 {
208 	struct snd_device *dev;
209 	int err = 0;
210 
211 	snd_assert(card != NULL, return -ENXIO);
212 	list_for_each_entry(dev, &card->devices, 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(struct snd_card *card, snd_device_cmd_t cmd)
224 {
225 	struct snd_device *dev;
226 	int err;
227 	unsigned int range_low, range_high;
228 
229 	snd_assert(card != NULL, return -ENXIO);
230 	range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
231 	range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
232       __again:
233 	list_for_each_entry(dev, &card->devices, list) {
234 		if (dev->type >= range_low && dev->type <= range_high) {
235 			if ((err = snd_device_free(card, dev->device_data)) < 0)
236 				return err;
237 			goto __again;
238 		}
239 	}
240 	return 0;
241 }
242