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  */
snd_device_new(struct snd_card * card,enum snd_device_type type,void * device_data,const struct snd_device_ops * ops)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 
__snd_device_disconnect(struct snd_device * dev)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 
__snd_device_free(struct snd_device * dev)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 
look_for_dev(struct snd_card * card,void * device_data)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  */
snd_device_disconnect(struct snd_card * card,void * device_data)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  */
snd_device_free(struct snd_card * card,void * device_data)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 
__snd_device_register(struct snd_device * dev)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  */
snd_device_register(struct snd_card * card,void * device_data)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  */
snd_device_register_all(struct snd_card * card)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  */
snd_device_disconnect_all(struct snd_card * card)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  */
snd_device_free_all(struct snd_card * card)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  */
snd_device_get_state(struct snd_card * card,void * device_data)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