1/*
2 *  Advanced Linux Sound Architecture
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/init.h>
23#include <linux/slab.h>
24#include <linux/time.h>
25#include <linux/device.h>
26#include <linux/module.h>
27#include <sound/core.h>
28#include <sound/minors.h>
29#include <sound/info.h>
30#include <sound/control.h>
31#include <sound/initval.h>
32#include <linux/kmod.h>
33#include <linux/mutex.h>
34
35static int major = CONFIG_SND_MAJOR;
36int snd_major;
37EXPORT_SYMBOL(snd_major);
38
39static int cards_limit = 1;
40
41MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
42MODULE_DESCRIPTION("Advanced Linux Sound Architecture driver for soundcards.");
43MODULE_LICENSE("GPL");
44module_param(major, int, 0444);
45MODULE_PARM_DESC(major, "Major # for sound driver.");
46module_param(cards_limit, int, 0444);
47MODULE_PARM_DESC(cards_limit, "Count of auto-loadable soundcards.");
48MODULE_ALIAS_CHARDEV_MAJOR(CONFIG_SND_MAJOR);
49
50/* this one holds the actual max. card number currently available.
51 * as default, it's identical with cards_limit option.  when more
52 * modules are loaded manually, this limit number increases, too.
53 */
54int snd_ecards_limit;
55EXPORT_SYMBOL(snd_ecards_limit);
56
57static struct snd_minor *snd_minors[SNDRV_OS_MINORS];
58static DEFINE_MUTEX(sound_mutex);
59
60#ifdef CONFIG_MODULES
61
62/**
63 * snd_request_card - try to load the card module
64 * @card: the card number
65 *
66 * Tries to load the module "snd-card-X" for the given card number
67 * via request_module.  Returns immediately if already loaded.
68 */
69void snd_request_card(int card)
70{
71	if (snd_card_locked(card))
72		return;
73	if (card < 0 || card >= cards_limit)
74		return;
75	request_module("snd-card-%i", card);
76}
77
78EXPORT_SYMBOL(snd_request_card);
79
80static void snd_request_other(int minor)
81{
82	char *str;
83
84	switch (minor) {
85	case SNDRV_MINOR_SEQUENCER:	str = "snd-seq";	break;
86	case SNDRV_MINOR_TIMER:		str = "snd-timer";	break;
87	default:			return;
88	}
89	request_module(str);
90}
91
92#endif	/* modular kernel */
93
94/**
95 * snd_lookup_minor_data - get user data of a registered device
96 * @minor: the minor number
97 * @type: device type (SNDRV_DEVICE_TYPE_XXX)
98 *
99 * Checks that a minor device with the specified type is registered, and returns
100 * its user data pointer.
101 *
102 * This function increments the reference counter of the card instance
103 * if an associated instance with the given minor number and type is found.
104 * The caller must call snd_card_unref() appropriately later.
105 *
106 * Return: The user data pointer if the specified device is found. %NULL
107 * otherwise.
108 */
109void *snd_lookup_minor_data(unsigned int minor, int type)
110{
111	struct snd_minor *mreg;
112	void *private_data;
113
114	if (minor >= ARRAY_SIZE(snd_minors))
115		return NULL;
116	mutex_lock(&sound_mutex);
117	mreg = snd_minors[minor];
118	if (mreg && mreg->type == type) {
119		private_data = mreg->private_data;
120		if (private_data && mreg->card_ptr)
121			get_device(&mreg->card_ptr->card_dev);
122	} else
123		private_data = NULL;
124	mutex_unlock(&sound_mutex);
125	return private_data;
126}
127
128EXPORT_SYMBOL(snd_lookup_minor_data);
129
130#ifdef CONFIG_MODULES
131static struct snd_minor *autoload_device(unsigned int minor)
132{
133	int dev;
134	mutex_unlock(&sound_mutex); /* release lock temporarily */
135	dev = SNDRV_MINOR_DEVICE(minor);
136	if (dev == SNDRV_MINOR_CONTROL) {
137		/* /dev/aloadC? */
138		int card = SNDRV_MINOR_CARD(minor);
139		if (snd_cards[card] == NULL)
140			snd_request_card(card);
141	} else if (dev == SNDRV_MINOR_GLOBAL) {
142		/* /dev/aloadSEQ */
143		snd_request_other(minor);
144	}
145	mutex_lock(&sound_mutex); /* reacuire lock */
146	return snd_minors[minor];
147}
148#else /* !CONFIG_MODULES */
149#define autoload_device(minor)	NULL
150#endif /* CONFIG_MODULES */
151
152static int snd_open(struct inode *inode, struct file *file)
153{
154	unsigned int minor = iminor(inode);
155	struct snd_minor *mptr = NULL;
156	const struct file_operations *new_fops;
157	int err = 0;
158
159	if (minor >= ARRAY_SIZE(snd_minors))
160		return -ENODEV;
161	mutex_lock(&sound_mutex);
162	mptr = snd_minors[minor];
163	if (mptr == NULL) {
164		mptr = autoload_device(minor);
165		if (!mptr) {
166			mutex_unlock(&sound_mutex);
167			return -ENODEV;
168		}
169	}
170	new_fops = fops_get(mptr->f_ops);
171	mutex_unlock(&sound_mutex);
172	if (!new_fops)
173		return -ENODEV;
174	replace_fops(file, new_fops);
175
176	if (file->f_op->open)
177		err = file->f_op->open(inode, file);
178	return err;
179}
180
181static const struct file_operations snd_fops =
182{
183	.owner =	THIS_MODULE,
184	.open =		snd_open,
185	.llseek =	noop_llseek,
186};
187
188#ifdef CONFIG_SND_DYNAMIC_MINORS
189static int snd_find_free_minor(int type, struct snd_card *card, int dev)
190{
191	int minor;
192
193	/* static minors for module auto loading */
194	if (type == SNDRV_DEVICE_TYPE_SEQUENCER)
195		return SNDRV_MINOR_SEQUENCER;
196	if (type == SNDRV_DEVICE_TYPE_TIMER)
197		return SNDRV_MINOR_TIMER;
198
199	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
200		/* skip static minors still used for module auto loading */
201		if (SNDRV_MINOR_DEVICE(minor) == SNDRV_MINOR_CONTROL)
202			continue;
203		if (minor == SNDRV_MINOR_SEQUENCER ||
204		    minor == SNDRV_MINOR_TIMER)
205			continue;
206		if (!snd_minors[minor])
207			return minor;
208	}
209	return -EBUSY;
210}
211#else
212static int snd_find_free_minor(int type, struct snd_card *card, int dev)
213{
214	int minor;
215
216	switch (type) {
217	case SNDRV_DEVICE_TYPE_SEQUENCER:
218	case SNDRV_DEVICE_TYPE_TIMER:
219		minor = type;
220		break;
221	case SNDRV_DEVICE_TYPE_CONTROL:
222		if (snd_BUG_ON(!card))
223			return -EINVAL;
224		minor = SNDRV_MINOR(card->number, type);
225		break;
226	case SNDRV_DEVICE_TYPE_HWDEP:
227	case SNDRV_DEVICE_TYPE_RAWMIDI:
228	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
229	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
230	case SNDRV_DEVICE_TYPE_COMPRESS:
231		if (snd_BUG_ON(!card))
232			return -EINVAL;
233		minor = SNDRV_MINOR(card->number, type + dev);
234		break;
235	default:
236		return -EINVAL;
237	}
238	if (snd_BUG_ON(minor < 0 || minor >= SNDRV_OS_MINORS))
239		return -EINVAL;
240	if (snd_minors[minor])
241		return -EBUSY;
242	return minor;
243}
244#endif
245
246/**
247 * snd_register_device - Register the ALSA device file for the card
248 * @type: the device type, SNDRV_DEVICE_TYPE_XXX
249 * @card: the card instance
250 * @dev: the device index
251 * @f_ops: the file operations
252 * @private_data: user pointer for f_ops->open()
253 * @device: the device to register
254 *
255 * Registers an ALSA device file for the given card.
256 * The operators have to be set in reg parameter.
257 *
258 * Return: Zero if successful, or a negative error code on failure.
259 */
260int snd_register_device(int type, struct snd_card *card, int dev,
261			const struct file_operations *f_ops,
262			void *private_data, struct device *device)
263{
264	int minor;
265	int err = 0;
266	struct snd_minor *preg;
267
268	if (snd_BUG_ON(!device))
269		return -EINVAL;
270
271	preg = kmalloc(sizeof *preg, GFP_KERNEL);
272	if (preg == NULL)
273		return -ENOMEM;
274	preg->type = type;
275	preg->card = card ? card->number : -1;
276	preg->device = dev;
277	preg->f_ops = f_ops;
278	preg->private_data = private_data;
279	preg->card_ptr = card;
280	mutex_lock(&sound_mutex);
281	minor = snd_find_free_minor(type, card, dev);
282	if (minor < 0) {
283		err = minor;
284		goto error;
285	}
286
287	preg->dev = device;
288	device->devt = MKDEV(major, minor);
289	err = device_add(device);
290	if (err < 0)
291		goto error;
292
293	snd_minors[minor] = preg;
294 error:
295	mutex_unlock(&sound_mutex);
296	if (err < 0)
297		kfree(preg);
298	return err;
299}
300EXPORT_SYMBOL(snd_register_device);
301
302/**
303 * snd_unregister_device - unregister the device on the given card
304 * @dev: the device instance
305 *
306 * Unregisters the device file already registered via
307 * snd_register_device().
308 *
309 * Return: Zero if successful, or a negative error code on failure.
310 */
311int snd_unregister_device(struct device *dev)
312{
313	int minor;
314	struct snd_minor *preg;
315
316	mutex_lock(&sound_mutex);
317	for (minor = 0; minor < ARRAY_SIZE(snd_minors); ++minor) {
318		preg = snd_minors[minor];
319		if (preg && preg->dev == dev) {
320			snd_minors[minor] = NULL;
321			device_del(dev);
322			kfree(preg);
323			break;
324		}
325	}
326	mutex_unlock(&sound_mutex);
327	if (minor >= ARRAY_SIZE(snd_minors))
328		return -ENOENT;
329	return 0;
330}
331EXPORT_SYMBOL(snd_unregister_device);
332
333#ifdef CONFIG_SND_PROC_FS
334/*
335 *  INFO PART
336 */
337static const char *snd_device_type_name(int type)
338{
339	switch (type) {
340	case SNDRV_DEVICE_TYPE_CONTROL:
341		return "control";
342	case SNDRV_DEVICE_TYPE_HWDEP:
343		return "hardware dependent";
344	case SNDRV_DEVICE_TYPE_RAWMIDI:
345		return "raw midi";
346	case SNDRV_DEVICE_TYPE_PCM_PLAYBACK:
347		return "digital audio playback";
348	case SNDRV_DEVICE_TYPE_PCM_CAPTURE:
349		return "digital audio capture";
350	case SNDRV_DEVICE_TYPE_SEQUENCER:
351		return "sequencer";
352	case SNDRV_DEVICE_TYPE_TIMER:
353		return "timer";
354	default:
355		return "?";
356	}
357}
358
359static void snd_minor_info_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
360{
361	int minor;
362	struct snd_minor *mptr;
363
364	mutex_lock(&sound_mutex);
365	for (minor = 0; minor < SNDRV_OS_MINORS; ++minor) {
366		if (!(mptr = snd_minors[minor]))
367			continue;
368		if (mptr->card >= 0) {
369			if (mptr->device >= 0)
370				snd_iprintf(buffer, "%3i: [%2i-%2i]: %s\n",
371					    minor, mptr->card, mptr->device,
372					    snd_device_type_name(mptr->type));
373			else
374				snd_iprintf(buffer, "%3i: [%2i]   : %s\n",
375					    minor, mptr->card,
376					    snd_device_type_name(mptr->type));
377		} else
378			snd_iprintf(buffer, "%3i:        : %s\n", minor,
379				    snd_device_type_name(mptr->type));
380	}
381	mutex_unlock(&sound_mutex);
382}
383
384int __init snd_minor_info_init(void)
385{
386	struct snd_info_entry *entry;
387
388	entry = snd_info_create_module_entry(THIS_MODULE, "devices", NULL);
389	if (!entry)
390		return -ENOMEM;
391	entry->c.text.read = snd_minor_info_read;
392	return snd_info_register(entry); /* freed in error path */
393}
394#endif /* CONFIG_SND_PROC_FS */
395
396/*
397 *  INIT PART
398 */
399
400static int __init alsa_sound_init(void)
401{
402	snd_major = major;
403	snd_ecards_limit = cards_limit;
404	if (register_chrdev(major, "alsa", &snd_fops)) {
405		pr_err("ALSA core: unable to register native major device number %d\n", major);
406		return -EIO;
407	}
408	if (snd_info_init() < 0) {
409		unregister_chrdev(major, "alsa");
410		return -ENOMEM;
411	}
412#ifndef MODULE
413	pr_info("Advanced Linux Sound Architecture Driver Initialized.\n");
414#endif
415	return 0;
416}
417
418static void __exit alsa_sound_exit(void)
419{
420	snd_info_done();
421	unregister_chrdev(major, "alsa");
422}
423
424subsys_initcall(alsa_sound_init);
425module_exit(alsa_sound_exit);
426