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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  */
snd_device_new(struct snd_card * card,enum snd_device_type type,void * device_data,struct snd_device_ops * ops)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 	struct list_head *p;
49 
50 	if (snd_BUG_ON(!card || !device_data || !ops))
51 		return -ENXIO;
52 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
53 	if (!dev)
54 		return -ENOMEM;
55 	INIT_LIST_HEAD(&dev->list);
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 
62 	/* insert the entry in an incrementally sorted list */
63 	list_for_each_prev(p, &card->devices) {
64 		struct snd_device *pdev = list_entry(p, struct snd_device, list);
65 		if ((unsigned int)pdev->type <= (unsigned int)type)
66 			break;
67 	}
68 
69 	list_add(&dev->list, p);
70 	return 0;
71 }
72 EXPORT_SYMBOL(snd_device_new);
73 
__snd_device_disconnect(struct snd_device * dev)74 static void __snd_device_disconnect(struct snd_device *dev)
75 {
76 	if (dev->state == SNDRV_DEV_REGISTERED) {
77 		if (dev->ops->dev_disconnect &&
78 		    dev->ops->dev_disconnect(dev))
79 			dev_err(dev->card->dev, "device disconnect failure\n");
80 		dev->state = SNDRV_DEV_DISCONNECTED;
81 	}
82 }
83 
__snd_device_free(struct snd_device * dev)84 static void __snd_device_free(struct snd_device *dev)
85 {
86 	/* unlink */
87 	list_del(&dev->list);
88 
89 	__snd_device_disconnect(dev);
90 	if (dev->ops->dev_free) {
91 		if (dev->ops->dev_free(dev))
92 			dev_err(dev->card->dev, "device free failure\n");
93 	}
94 	kfree(dev);
95 }
96 
look_for_dev(struct snd_card * card,void * device_data)97 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
98 {
99 	struct snd_device *dev;
100 
101 	list_for_each_entry(dev, &card->devices, list)
102 		if (dev->device_data == device_data)
103 			return dev;
104 
105 	return NULL;
106 }
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  * Return: Zero if successful, or a negative error code on failure or if the
119  * device not found.
120  */
snd_device_disconnect(struct snd_card * card,void * device_data)121 void 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;
127 	dev = look_for_dev(card, device_data);
128 	if (dev)
129 		__snd_device_disconnect(dev);
130 	else
131 		dev_dbg(card->dev, "device disconnect %p (from %pF), not found\n",
132 			device_data, __builtin_return_address(0));
133 }
134 EXPORT_SYMBOL_GPL(snd_device_disconnect);
135 
136 /**
137  * snd_device_free - release the device from the card
138  * @card: the card instance
139  * @device_data: the data pointer to release
140  *
141  * Removes the device from the list on the card and invokes the
142  * callbacks, dev_disconnect and dev_free, corresponding to the state.
143  * Then release the device.
144  */
snd_device_free(struct snd_card * card,void * device_data)145 void snd_device_free(struct snd_card *card, void *device_data)
146 {
147 	struct snd_device *dev;
148 
149 	if (snd_BUG_ON(!card || !device_data))
150 		return;
151 	dev = look_for_dev(card, device_data);
152 	if (dev)
153 		__snd_device_free(dev);
154 	else
155 		dev_dbg(card->dev, "device free %p (from %pF), not found\n",
156 			device_data, __builtin_return_address(0));
157 }
158 EXPORT_SYMBOL(snd_device_free);
159 
__snd_device_register(struct snd_device * dev)160 static int __snd_device_register(struct snd_device *dev)
161 {
162 	if (dev->state == SNDRV_DEV_BUILD) {
163 		if (dev->ops->dev_register) {
164 			int err = dev->ops->dev_register(dev);
165 			if (err < 0)
166 				return err;
167 		}
168 		dev->state = SNDRV_DEV_REGISTERED;
169 	}
170 	return 0;
171 }
172 
173 /**
174  * snd_device_register - register the device
175  * @card: the card instance
176  * @device_data: the data pointer to register
177  *
178  * Registers the device which was already created via
179  * snd_device_new().  Usually this is called from snd_card_register(),
180  * but it can be called later if any new devices are created after
181  * invocation of snd_card_register().
182  *
183  * Return: Zero if successful, or a negative error code on failure or if the
184  * device not found.
185  */
snd_device_register(struct snd_card * card,void * device_data)186 int snd_device_register(struct snd_card *card, void *device_data)
187 {
188 	struct snd_device *dev;
189 
190 	if (snd_BUG_ON(!card || !device_data))
191 		return -ENXIO;
192 	dev = look_for_dev(card, device_data);
193 	if (dev)
194 		return __snd_device_register(dev);
195 	snd_BUG();
196 	return -ENXIO;
197 }
198 EXPORT_SYMBOL(snd_device_register);
199 
200 /*
201  * register all the devices on the card.
202  * called from init.c
203  */
snd_device_register_all(struct snd_card * card)204 int snd_device_register_all(struct snd_card *card)
205 {
206 	struct snd_device *dev;
207 	int err;
208 
209 	if (snd_BUG_ON(!card))
210 		return -ENXIO;
211 	list_for_each_entry(dev, &card->devices, list) {
212 		err = __snd_device_register(dev);
213 		if (err < 0)
214 			return err;
215 	}
216 	return 0;
217 }
218 
219 /*
220  * disconnect all the devices on the card.
221  * called from init.c
222  */
snd_device_disconnect_all(struct snd_card * card)223 void snd_device_disconnect_all(struct snd_card *card)
224 {
225 	struct snd_device *dev;
226 
227 	if (snd_BUG_ON(!card))
228 		return;
229 	list_for_each_entry_reverse(dev, &card->devices, list)
230 		__snd_device_disconnect(dev);
231 }
232 
233 /*
234  * release all the devices on the card.
235  * called from init.c
236  */
snd_device_free_all(struct snd_card * card)237 void snd_device_free_all(struct snd_card *card)
238 {
239 	struct snd_device *dev, *next;
240 
241 	if (snd_BUG_ON(!card))
242 		return;
243 	list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
244 		__snd_device_free(dev);
245 }
246