xref: /openbmc/linux/sound/core/device.c (revision 115b94d5)
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 
49 	if (snd_BUG_ON(!card || !device_data || !ops))
50 		return -ENXIO;
51 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
52 	if (dev == NULL) {
53 		dev_err(card->dev, "Cannot allocate device, type=%d\n", type);
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  * Return: 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 	if (snd_BUG_ON(!card || !device_data))
84 		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 				dev_err(card->dev,
94 					"device disconnect failure\n");
95 		if (dev->ops->dev_free) {
96 			if (dev->ops->dev_free(dev))
97 				dev_err(card->dev, "device free failure\n");
98 		}
99 		kfree(dev);
100 		return 0;
101 	}
102 	dev_dbg(card->dev, "device free %p (from %pF), not found\n",
103 		device_data, __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  * Return: 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 	if (snd_BUG_ON(!card || !device_data))
127 		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 				dev_err(card->dev,
135 					"device disconnect failure\n");
136 			dev->state = SNDRV_DEV_DISCONNECTED;
137 		}
138 		return 0;
139 	}
140 	dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
141 		device_data, __builtin_return_address(0));
142 	return -ENXIO;
143 }
144 
145 /**
146  * snd_device_register - register the device
147  * @card: the card instance
148  * @device_data: the data pointer to register
149  *
150  * Registers the device which was already created via
151  * snd_device_new().  Usually this is called from snd_card_register(),
152  * but it can be called later if any new devices are created after
153  * invocation of snd_card_register().
154  *
155  * Return: Zero if successful, or a negative error code on failure or if the
156  * device not found.
157  */
158 int snd_device_register(struct snd_card *card, void *device_data)
159 {
160 	struct snd_device *dev;
161 	int err;
162 
163 	if (snd_BUG_ON(!card || !device_data))
164 		return -ENXIO;
165 	list_for_each_entry(dev, &card->devices, list) {
166 		if (dev->device_data != device_data)
167 			continue;
168 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
169 			if ((err = dev->ops->dev_register(dev)) < 0)
170 				return err;
171 			dev->state = SNDRV_DEV_REGISTERED;
172 			return 0;
173 		}
174 		dev_dbg(card->dev, "snd_device_register busy\n");
175 		return -EBUSY;
176 	}
177 	snd_BUG();
178 	return -ENXIO;
179 }
180 
181 EXPORT_SYMBOL(snd_device_register);
182 
183 /*
184  * register all the devices on the card.
185  * called from init.c
186  */
187 int snd_device_register_all(struct snd_card *card)
188 {
189 	struct snd_device *dev;
190 	int err;
191 
192 	if (snd_BUG_ON(!card))
193 		return -ENXIO;
194 	list_for_each_entry(dev, &card->devices, list) {
195 		if (dev->state == SNDRV_DEV_BUILD && dev->ops->dev_register) {
196 			if ((err = dev->ops->dev_register(dev)) < 0)
197 				return err;
198 			dev->state = SNDRV_DEV_REGISTERED;
199 		}
200 	}
201 	return 0;
202 }
203 
204 /*
205  * disconnect all the devices on the card.
206  * called from init.c
207  */
208 int snd_device_disconnect_all(struct snd_card *card)
209 {
210 	struct snd_device *dev;
211 	int err = 0;
212 
213 	if (snd_BUG_ON(!card))
214 		return -ENXIO;
215 	list_for_each_entry(dev, &card->devices, list) {
216 		if (snd_device_disconnect(card, dev->device_data) < 0)
217 			err = -ENXIO;
218 	}
219 	return err;
220 }
221 
222 /*
223  * release all the devices on the card.
224  * called from init.c
225  */
226 int snd_device_free_all(struct snd_card *card, enum snd_device_cmd cmd)
227 {
228 	struct snd_device *dev;
229 	int err;
230 	unsigned int range_low, range_high, type;
231 
232 	if (snd_BUG_ON(!card))
233 		return -ENXIO;
234 	range_low = (unsigned int)cmd * SNDRV_DEV_TYPE_RANGE_SIZE;
235 	range_high = range_low + SNDRV_DEV_TYPE_RANGE_SIZE - 1;
236       __again:
237 	list_for_each_entry(dev, &card->devices, list) {
238 		type = (unsigned int)dev->type;
239 		if (type >= range_low && type <= range_high) {
240 			if ((err = snd_device_free(card, dev->device_data)) < 0)
241 				return err;
242 			goto __again;
243 		}
244 	}
245 	return 0;
246 }
247