xref: /openbmc/linux/sound/core/device.c (revision 87c2ce3b)
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(struct snd_card *card, snd_device_type_t type,
45 		   void *device_data, struct snd_device_ops *ops)
46 {
47 	struct snd_device *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 		snd_printk(KERN_ERR "Cannot allocate device\n");
55 		return -ENOMEM;
56 	}
57 	dev->card = card;
58 	dev->type = type;
59 	dev->state = SNDRV_DEV_BUILD;
60 	dev->device_data = device_data;
61 	dev->ops = ops;
62 	list_add(&dev->list, &card->devices);	/* add to the head of list */
63 	return 0;
64 }
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  * callback, dev_unregister or 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  */
78 int snd_device_free(struct snd_card *card, void *device_data)
79 {
80 	struct list_head *list;
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(list, &card->devices) {
86 		dev = snd_device(list);
87 		if (dev->device_data != device_data)
88 			continue;
89 		/* unlink */
90 		list_del(&dev->list);
91 		if ((dev->state == SNDRV_DEV_REGISTERED ||
92 		     dev->state == SNDRV_DEV_DISCONNECTED) &&
93 		    dev->ops->dev_unregister) {
94 			if (dev->ops->dev_unregister(dev))
95 				snd_printk(KERN_ERR "device unregister failure\n");
96 		} else {
97 			if (dev->ops->dev_free) {
98 				if (dev->ops->dev_free(dev))
99 					snd_printk(KERN_ERR "device free failure\n");
100 			}
101 		}
102 		kfree(dev);
103 		return 0;
104 	}
105 	snd_printd("device free %p (from %p), not found\n", device_data,
106 		   __builtin_return_address(0));
107 	return -ENXIO;
108 }
109 
110 /**
111  * snd_device_disconnect - disconnect the device
112  * @card: the card instance
113  * @device_data: the data pointer to disconnect
114  *
115  * Turns the device into the disconnection state, invoking
116  * dev_disconnect callback, if the device was already registered.
117  *
118  * Usually called from snd_card_disconnect().
119  *
120  * Returns zero if successful, or a negative error code on failure or if the
121  * device not found.
122  */
123 int snd_device_disconnect(struct snd_card *card, void *device_data)
124 {
125 	struct list_head *list;
126 	struct snd_device *dev;
127 
128 	snd_assert(card != NULL, return -ENXIO);
129 	snd_assert(device_data != NULL, return -ENXIO);
130 	list_for_each(list, &card->devices) {
131 		dev = snd_device(list);
132 		if (dev->device_data != device_data)
133 			continue;
134 		if (dev->state == SNDRV_DEV_REGISTERED &&
135 		    dev->ops->dev_disconnect) {
136 			if (dev->ops->dev_disconnect(dev))
137 				snd_printk(KERN_ERR "device disconnect failure\n");
138 			dev->state = SNDRV_DEV_DISCONNECTED;
139 		}
140 		return 0;
141 	}
142 	snd_printd("device disconnect %p (from %p), not found\n", device_data,
143 		   __builtin_return_address(0));
144 	return -ENXIO;
145 }
146 
147 /**
148  * snd_device_register - register the device
149  * @card: the card instance
150  * @device_data: the data pointer to register
151  *
152  * Registers the device which was already created via
153  * snd_device_new().  Usually this is called from snd_card_register(),
154  * but it can be called later if any new devices are created after
155  * invocation of snd_card_register().
156  *
157  * Returns zero if successful, or a negative error code on failure or if the
158  * device not found.
159  */
160 int snd_device_register(struct snd_card *card, void *device_data)
161 {
162 	struct list_head *list;
163 	struct snd_device *dev;
164 	int err;
165 
166 	snd_assert(card != NULL, return -ENXIO);
167 	snd_assert(device_data != NULL, return -ENXIO);
168 	list_for_each(list, &card->devices) {
169 		dev = snd_device(list);
170 		if (dev->device_data != device_data)
171 			continue;
172 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
173 			if ((err = dev->ops->dev_register(dev)) < 0)
174 				return err;
175 			dev->state = SNDRV_DEV_REGISTERED;
176 			return 0;
177 		}
178 		snd_printd("snd_device_register busy\n");
179 		return -EBUSY;
180 	}
181 	snd_BUG();
182 	return -ENXIO;
183 }
184 
185 /*
186  * register all the devices on the card.
187  * called from init.c
188  */
189 int snd_device_register_all(struct snd_card *card)
190 {
191 	struct list_head *list;
192 	struct snd_device *dev;
193 	int err;
194 
195 	snd_assert(card != NULL, return -ENXIO);
196 	list_for_each(list, &card->devices) {
197 		dev = snd_device(list);
198 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
199 			if ((err = dev->ops->dev_register(dev)) < 0)
200 				return err;
201 			dev->state = SNDRV_DEV_REGISTERED;
202 		}
203 	}
204 	return 0;
205 }
206 
207 /*
208  * disconnect all the devices on the card.
209  * called from init.c
210  */
211 int snd_device_disconnect_all(struct snd_card *card)
212 {
213 	struct snd_device *dev;
214 	struct list_head *list;
215 	int err = 0;
216 
217 	snd_assert(card != NULL, return -ENXIO);
218 	list_for_each(list, &card->devices) {
219 		dev = snd_device(list);
220 		if (snd_device_disconnect(card, dev->device_data) < 0)
221 			err = -ENXIO;
222 	}
223 	return err;
224 }
225 
226 /*
227  * release all the devices on the card.
228  * called from init.c
229  */
230 int snd_device_free_all(struct snd_card *card, snd_device_cmd_t cmd)
231 {
232 	struct snd_device *dev;
233 	struct list_head *list;
234 	int err;
235 	unsigned int range_low, range_high;
236 
237 	snd_assert(card != NULL, return -ENXIO);
238 	range_low = cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
239 	range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
240       __again:
241 	list_for_each(list, &card->devices) {
242 		dev = snd_device(list);
243 		if (dev->type >= range_low && dev->type <= range_high) {
244 			if ((err = snd_device_free(card, dev->device_data)) < 0)
245 				return err;
246 			goto __again;
247 		}
248 	}
249 	return 0;
250 }
251