1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Device management routines
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7 #include <linux/slab.h>
8 #include <linux/time.h>
9 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <sound/core.h>
12
13 /**
14 * snd_device_new - create an ALSA device component
15 * @card: the card instance
16 * @type: the device type, SNDRV_DEV_XXX
17 * @device_data: the data pointer of this device
18 * @ops: the operator table
19 *
20 * Creates a new device component for the given data pointer.
21 * The device will be assigned to the card and managed together
22 * by the card.
23 *
24 * The data pointer plays a role as the identifier, too, so the
25 * pointer address must be unique and unchanged.
26 *
27 * Return: Zero if successful, or a negative error code on failure.
28 */
29 int snd_device_new(struct snd_card *card, enum snd_device_type type,
30 void *device_data, const struct snd_device_ops *ops)
31 {
32 struct snd_device *dev;
33 struct list_head *p;
34
35 if (snd_BUG_ON(!card || !device_data || !ops))
36 return -ENXIO;
37 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
38 if (!dev)
39 return -ENOMEM;
40 INIT_LIST_HEAD(&dev->list);
41 dev->card = card;
42 dev->type = type;
43 dev->state = SNDRV_DEV_BUILD;
44 dev->device_data = device_data;
45 dev->ops = ops;
46
47 /* insert the entry in an incrementally sorted list */
48 list_for_each_prev(p, &card->devices) {
49 struct snd_device *pdev = list_entry(p, struct snd_device, list);
50 if ((unsigned int)pdev->type <= (unsigned int)type)
51 break;
52 }
53
54 list_add(&dev->list, p);
55 return 0;
56 }
57 EXPORT_SYMBOL(snd_device_new);
58
59 static void __snd_device_disconnect(struct snd_device *dev)
60 {
61 if (dev->state == SNDRV_DEV_REGISTERED) {
62 if (dev->ops->dev_disconnect &&
63 dev->ops->dev_disconnect(dev))
64 dev_err(dev->card->dev, "device disconnect failure\n");
65 dev->state = SNDRV_DEV_DISCONNECTED;
66 }
67 }
68
69 static void __snd_device_free(struct snd_device *dev)
70 {
71 /* unlink */
72 list_del(&dev->list);
73
74 __snd_device_disconnect(dev);
75 if (dev->ops->dev_free) {
76 if (dev->ops->dev_free(dev))
77 dev_err(dev->card->dev, "device free failure\n");
78 }
79 kfree(dev);
80 }
81
82 static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
83 {
84 struct snd_device *dev;
85
86 list_for_each_entry(dev, &card->devices, list)
87 if (dev->device_data == device_data)
88 return dev;
89
90 return NULL;
91 }
92
93 /**
94 * snd_device_disconnect - disconnect the device
95 * @card: the card instance
96 * @device_data: the data pointer to disconnect
97 *
98 * Turns the device into the disconnection state, invoking
99 * dev_disconnect callback, if the device was already registered.
100 *
101 * Usually called from snd_card_disconnect().
102 *
103 * Return: Zero if successful, or a negative error code on failure or if the
104 * device not found.
105 */
106 void snd_device_disconnect(struct snd_card *card, void *device_data)
107 {
108 struct snd_device *dev;
109
110 if (snd_BUG_ON(!card || !device_data))
111 return;
112 dev = look_for_dev(card, device_data);
113 if (dev)
114 __snd_device_disconnect(dev);
115 else
116 dev_dbg(card->dev, "device disconnect %p (from %pS), not found\n",
117 device_data, __builtin_return_address(0));
118 }
119 EXPORT_SYMBOL_GPL(snd_device_disconnect);
120
121 /**
122 * snd_device_free - release the device from the card
123 * @card: the card instance
124 * @device_data: the data pointer to release
125 *
126 * Removes the device from the list on the card and invokes the
127 * callbacks, dev_disconnect and dev_free, corresponding to the state.
128 * Then release the device.
129 */
130 void snd_device_free(struct snd_card *card, void *device_data)
131 {
132 struct snd_device *dev;
133
134 if (snd_BUG_ON(!card || !device_data))
135 return;
136 dev = look_for_dev(card, device_data);
137 if (dev)
138 __snd_device_free(dev);
139 else
140 dev_dbg(card->dev, "device free %p (from %pS), not found\n",
141 device_data, __builtin_return_address(0));
142 }
143 EXPORT_SYMBOL(snd_device_free);
144
145 static int __snd_device_register(struct snd_device *dev)
146 {
147 if (dev->state == SNDRV_DEV_BUILD) {
148 if (dev->ops->dev_register) {
149 int err = dev->ops->dev_register(dev);
150 if (err < 0)
151 return err;
152 }
153 dev->state = SNDRV_DEV_REGISTERED;
154 }
155 return 0;
156 }
157
158 /**
159 * snd_device_register - register the device
160 * @card: the card instance
161 * @device_data: the data pointer to register
162 *
163 * Registers the device which was already created via
164 * snd_device_new(). Usually this is called from snd_card_register(),
165 * but it can be called later if any new devices are created after
166 * invocation of snd_card_register().
167 *
168 * Return: Zero if successful, or a negative error code on failure or if the
169 * device not found.
170 */
171 int snd_device_register(struct snd_card *card, void *device_data)
172 {
173 struct snd_device *dev;
174
175 if (snd_BUG_ON(!card || !device_data))
176 return -ENXIO;
177 dev = look_for_dev(card, device_data);
178 if (dev)
179 return __snd_device_register(dev);
180 snd_BUG();
181 return -ENXIO;
182 }
183 EXPORT_SYMBOL(snd_device_register);
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 snd_device *dev;
192 int err;
193
194 if (snd_BUG_ON(!card))
195 return -ENXIO;
196 list_for_each_entry(dev, &card->devices, list) {
197 err = __snd_device_register(dev);
198 if (err < 0)
199 return err;
200 }
201 return 0;
202 }
203
204 /*
205 * disconnect all the devices on the card.
206 * called from init.c
207 */
208 void snd_device_disconnect_all(struct snd_card *card)
209 {
210 struct snd_device *dev;
211
212 if (snd_BUG_ON(!card))
213 return;
214 list_for_each_entry_reverse(dev, &card->devices, list)
215 __snd_device_disconnect(dev);
216 }
217
218 /*
219 * release all the devices on the card.
220 * called from init.c
221 */
222 void snd_device_free_all(struct snd_card *card)
223 {
224 struct snd_device *dev, *next;
225
226 if (snd_BUG_ON(!card))
227 return;
228 list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
229 /* exception: free ctl and lowlevel stuff later */
230 if (dev->type == SNDRV_DEV_CONTROL ||
231 dev->type == SNDRV_DEV_LOWLEVEL)
232 continue;
233 __snd_device_free(dev);
234 }
235
236 /* free all */
237 list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
238 __snd_device_free(dev);
239 }
240
241 /**
242 * snd_device_get_state - Get the current state of the given device
243 * @card: the card instance
244 * @device_data: the data pointer to release
245 *
246 * Returns the current state of the given device object. For the valid
247 * device, either @SNDRV_DEV_BUILD, @SNDRV_DEV_REGISTERED or
248 * @SNDRV_DEV_DISCONNECTED is returned.
249 * Or for a non-existing device, -1 is returned as an error.
250 *
251 * Return: the current state, or -1 if not found
252 */
253 int snd_device_get_state(struct snd_card *card, void *device_data)
254 {
255 struct snd_device *dev;
256
257 dev = look_for_dev(card, device_data);
258 if (dev)
259 return dev->state;
260 return -1;
261 }
262 EXPORT_SYMBOL_GPL(snd_device_get_state);
263
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