xref: /openbmc/linux/sound/core/info.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /*
2  *  Information interface for ALSA driver
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/time.h>
24 #include <linux/mm.h>
25 #include <linux/smp_lock.h>
26 #include <linux/string.h>
27 #include <sound/core.h>
28 #include <sound/minors.h>
29 #include <sound/info.h>
30 #include <sound/version.h>
31 #include <linux/proc_fs.h>
32 #include <linux/mutex.h>
33 #include <stdarg.h>
34 
35 /*
36  *
37  */
38 
39 #ifdef CONFIG_PROC_FS
40 
41 int snd_info_check_reserved_words(const char *str)
42 {
43 	static char *reserved[] =
44 	{
45 		"version",
46 		"meminfo",
47 		"memdebug",
48 		"detect",
49 		"devices",
50 		"oss",
51 		"cards",
52 		"timers",
53 		"synth",
54 		"pcm",
55 		"seq",
56 		NULL
57 	};
58 	char **xstr = reserved;
59 
60 	while (*xstr) {
61 		if (!strcmp(*xstr, str))
62 			return 0;
63 		xstr++;
64 	}
65 	if (!strncmp(str, "card", 4))
66 		return 0;
67 	return 1;
68 }
69 
70 static DEFINE_MUTEX(info_mutex);
71 
72 struct snd_info_private_data {
73 	struct snd_info_buffer *rbuffer;
74 	struct snd_info_buffer *wbuffer;
75 	struct snd_info_entry *entry;
76 	void *file_private_data;
77 };
78 
79 static int snd_info_version_init(void);
80 static int snd_info_version_done(void);
81 static void snd_info_disconnect(struct snd_info_entry *entry);
82 
83 
84 /* resize the proc r/w buffer */
85 static int resize_info_buffer(struct snd_info_buffer *buffer,
86 			      unsigned int nsize)
87 {
88 	char *nbuf;
89 
90 	nsize = PAGE_ALIGN(nsize);
91 	nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL);
92 	if (! nbuf)
93 		return -ENOMEM;
94 
95 	buffer->buffer = nbuf;
96 	buffer->len = nsize;
97 	return 0;
98 }
99 
100 /**
101  * snd_iprintf - printf on the procfs buffer
102  * @buffer: the procfs buffer
103  * @fmt: the printf format
104  *
105  * Outputs the string on the procfs buffer just like printf().
106  *
107  * Returns the size of output string.
108  */
109 int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
110 {
111 	va_list args;
112 	int len, res;
113 	int err = 0;
114 
115 	might_sleep();
116 	if (buffer->stop || buffer->error)
117 		return 0;
118 	len = buffer->len - buffer->size;
119 	va_start(args, fmt);
120 	for (;;) {
121 		va_list ap;
122 		va_copy(ap, args);
123 		res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
124 		va_end(ap);
125 		if (res < len)
126 			break;
127 		err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
128 		if (err < 0)
129 			break;
130 		len = buffer->len - buffer->size;
131 	}
132 	va_end(args);
133 
134 	if (err < 0)
135 		return err;
136 	buffer->curr += res;
137 	buffer->size += res;
138 	return res;
139 }
140 
141 EXPORT_SYMBOL(snd_iprintf);
142 
143 /*
144 
145  */
146 
147 static struct proc_dir_entry *snd_proc_root;
148 struct snd_info_entry *snd_seq_root;
149 EXPORT_SYMBOL(snd_seq_root);
150 
151 #ifdef CONFIG_SND_OSSEMUL
152 struct snd_info_entry *snd_oss_root;
153 #endif
154 
155 static void snd_remove_proc_entry(struct proc_dir_entry *parent,
156 				  struct proc_dir_entry *de)
157 {
158 	if (de)
159 		remove_proc_entry(de->name, parent);
160 }
161 
162 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
163 {
164 	struct snd_info_private_data *data;
165 	struct snd_info_entry *entry;
166 	loff_t ret;
167 
168 	data = file->private_data;
169 	entry = data->entry;
170 	lock_kernel();
171 	switch (entry->content) {
172 	case SNDRV_INFO_CONTENT_TEXT:
173 		switch (orig) {
174 		case SEEK_SET:
175 			file->f_pos = offset;
176 			ret = file->f_pos;
177 			goto out;
178 		case SEEK_CUR:
179 			file->f_pos += offset;
180 			ret = file->f_pos;
181 			goto out;
182 		case SEEK_END:
183 		default:
184 			ret = -EINVAL;
185 			goto out;
186 		}
187 		break;
188 	case SNDRV_INFO_CONTENT_DATA:
189 		if (entry->c.ops->llseek) {
190 			ret = entry->c.ops->llseek(entry,
191 						    data->file_private_data,
192 						    file, offset, orig);
193 			goto out;
194 		}
195 		break;
196 	}
197 	ret = -ENXIO;
198 out:
199 	unlock_kernel();
200 	return ret;
201 }
202 
203 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
204 				   size_t count, loff_t * offset)
205 {
206 	struct snd_info_private_data *data;
207 	struct snd_info_entry *entry;
208 	struct snd_info_buffer *buf;
209 	size_t size = 0;
210 	loff_t pos;
211 
212 	data = file->private_data;
213 	if (snd_BUG_ON(!data))
214 		return -ENXIO;
215 	pos = *offset;
216 	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
217 		return -EIO;
218 	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
219 		return -EIO;
220 	entry = data->entry;
221 	switch (entry->content) {
222 	case SNDRV_INFO_CONTENT_TEXT:
223 		buf = data->rbuffer;
224 		if (buf == NULL)
225 			return -EIO;
226 		if (pos >= buf->size)
227 			return 0;
228 		size = buf->size - pos;
229 		size = min(count, size);
230 		if (copy_to_user(buffer, buf->buffer + pos, size))
231 			return -EFAULT;
232 		break;
233 	case SNDRV_INFO_CONTENT_DATA:
234 		if (entry->c.ops->read)
235 			size = entry->c.ops->read(entry,
236 						  data->file_private_data,
237 						  file, buffer, count, pos);
238 		break;
239 	}
240 	if ((ssize_t) size > 0)
241 		*offset = pos + size;
242 	return size;
243 }
244 
245 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
246 				    size_t count, loff_t * offset)
247 {
248 	struct snd_info_private_data *data;
249 	struct snd_info_entry *entry;
250 	struct snd_info_buffer *buf;
251 	ssize_t size = 0;
252 	loff_t pos;
253 
254 	data = file->private_data;
255 	if (snd_BUG_ON(!data))
256 		return -ENXIO;
257 	entry = data->entry;
258 	pos = *offset;
259 	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
260 		return -EIO;
261 	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
262 		return -EIO;
263 	switch (entry->content) {
264 	case SNDRV_INFO_CONTENT_TEXT:
265 		buf = data->wbuffer;
266 		if (buf == NULL)
267 			return -EIO;
268 		mutex_lock(&entry->access);
269 		if (pos + count >= buf->len) {
270 			if (resize_info_buffer(buf, pos + count)) {
271 				mutex_unlock(&entry->access);
272 				return -ENOMEM;
273 			}
274 		}
275 		if (copy_from_user(buf->buffer + pos, buffer, count)) {
276 			mutex_unlock(&entry->access);
277 			return -EFAULT;
278 		}
279 		buf->size = pos + count;
280 		mutex_unlock(&entry->access);
281 		size = count;
282 		break;
283 	case SNDRV_INFO_CONTENT_DATA:
284 		if (entry->c.ops->write)
285 			size = entry->c.ops->write(entry,
286 						   data->file_private_data,
287 						   file, buffer, count, pos);
288 		break;
289 	}
290 	if ((ssize_t) size > 0)
291 		*offset = pos + size;
292 	return size;
293 }
294 
295 static int snd_info_entry_open(struct inode *inode, struct file *file)
296 {
297 	struct snd_info_entry *entry;
298 	struct snd_info_private_data *data;
299 	struct snd_info_buffer *buffer;
300 	struct proc_dir_entry *p;
301 	int mode, err;
302 
303 	mutex_lock(&info_mutex);
304 	p = PDE(inode);
305 	entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
306 	if (entry == NULL || ! entry->p) {
307 		mutex_unlock(&info_mutex);
308 		return -ENODEV;
309 	}
310 	if (!try_module_get(entry->module)) {
311 		err = -EFAULT;
312 		goto __error1;
313 	}
314 	mode = file->f_flags & O_ACCMODE;
315 	if (mode == O_RDONLY || mode == O_RDWR) {
316 		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
317 		     entry->c.ops->read == NULL)) {
318 		    	err = -ENODEV;
319 		    	goto __error;
320 		}
321 	}
322 	if (mode == O_WRONLY || mode == O_RDWR) {
323 		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
324 		     entry->c.ops->write == NULL)) {
325 		    	err = -ENODEV;
326 		    	goto __error;
327 		}
328 	}
329 	data = kzalloc(sizeof(*data), GFP_KERNEL);
330 	if (data == NULL) {
331 		err = -ENOMEM;
332 		goto __error;
333 	}
334 	data->entry = entry;
335 	switch (entry->content) {
336 	case SNDRV_INFO_CONTENT_TEXT:
337 		if (mode == O_RDONLY || mode == O_RDWR) {
338 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
339 			if (buffer == NULL)
340 				goto __nomem;
341 			data->rbuffer = buffer;
342 			buffer->len = PAGE_SIZE;
343 			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
344 			if (buffer->buffer == NULL)
345 				goto __nomem;
346 		}
347 		if (mode == O_WRONLY || mode == O_RDWR) {
348 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
349 			if (buffer == NULL)
350 				goto __nomem;
351 			data->wbuffer = buffer;
352 			buffer->len = PAGE_SIZE;
353 			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
354 			if (buffer->buffer == NULL)
355 				goto __nomem;
356 		}
357 		break;
358 	case SNDRV_INFO_CONTENT_DATA:	/* data */
359 		if (entry->c.ops->open) {
360 			if ((err = entry->c.ops->open(entry, mode,
361 						      &data->file_private_data)) < 0) {
362 				kfree(data);
363 				goto __error;
364 			}
365 		}
366 		break;
367 	}
368 	file->private_data = data;
369 	mutex_unlock(&info_mutex);
370 	if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
371 	    (mode == O_RDONLY || mode == O_RDWR)) {
372 		if (entry->c.text.read) {
373 			mutex_lock(&entry->access);
374 			entry->c.text.read(entry, data->rbuffer);
375 			mutex_unlock(&entry->access);
376 		}
377 	}
378 	return 0;
379 
380  __nomem:
381 	if (data->rbuffer) {
382 		kfree(data->rbuffer->buffer);
383 		kfree(data->rbuffer);
384 	}
385 	if (data->wbuffer) {
386 		kfree(data->wbuffer->buffer);
387 		kfree(data->wbuffer);
388 	}
389 	kfree(data);
390 	err = -ENOMEM;
391       __error:
392 	module_put(entry->module);
393       __error1:
394 	mutex_unlock(&info_mutex);
395 	return err;
396 }
397 
398 static int snd_info_entry_release(struct inode *inode, struct file *file)
399 {
400 	struct snd_info_entry *entry;
401 	struct snd_info_private_data *data;
402 	int mode;
403 
404 	mode = file->f_flags & O_ACCMODE;
405 	data = file->private_data;
406 	entry = data->entry;
407 	switch (entry->content) {
408 	case SNDRV_INFO_CONTENT_TEXT:
409 		if (data->rbuffer) {
410 			kfree(data->rbuffer->buffer);
411 			kfree(data->rbuffer);
412 		}
413 		if (data->wbuffer) {
414 			if (entry->c.text.write) {
415 				entry->c.text.write(entry, data->wbuffer);
416 				if (data->wbuffer->error) {
417 					snd_printk(KERN_WARNING "data write error to %s (%i)\n",
418 						entry->name,
419 						data->wbuffer->error);
420 				}
421 			}
422 			kfree(data->wbuffer->buffer);
423 			kfree(data->wbuffer);
424 		}
425 		break;
426 	case SNDRV_INFO_CONTENT_DATA:
427 		if (entry->c.ops->release)
428 			entry->c.ops->release(entry, mode,
429 					      data->file_private_data);
430 		break;
431 	}
432 	module_put(entry->module);
433 	kfree(data);
434 	return 0;
435 }
436 
437 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
438 {
439 	struct snd_info_private_data *data;
440 	struct snd_info_entry *entry;
441 	unsigned int mask;
442 
443 	data = file->private_data;
444 	if (data == NULL)
445 		return 0;
446 	entry = data->entry;
447 	mask = 0;
448 	switch (entry->content) {
449 	case SNDRV_INFO_CONTENT_DATA:
450 		if (entry->c.ops->poll)
451 			return entry->c.ops->poll(entry,
452 						  data->file_private_data,
453 						  file, wait);
454 		if (entry->c.ops->read)
455 			mask |= POLLIN | POLLRDNORM;
456 		if (entry->c.ops->write)
457 			mask |= POLLOUT | POLLWRNORM;
458 		break;
459 	}
460 	return mask;
461 }
462 
463 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
464 				unsigned long arg)
465 {
466 	struct snd_info_private_data *data;
467 	struct snd_info_entry *entry;
468 
469 	data = file->private_data;
470 	if (data == NULL)
471 		return 0;
472 	entry = data->entry;
473 	switch (entry->content) {
474 	case SNDRV_INFO_CONTENT_DATA:
475 		if (entry->c.ops->ioctl)
476 			return entry->c.ops->ioctl(entry,
477 						   data->file_private_data,
478 						   file, cmd, arg);
479 		break;
480 	}
481 	return -ENOTTY;
482 }
483 
484 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
485 {
486 	struct inode *inode = file->f_path.dentry->d_inode;
487 	struct snd_info_private_data *data;
488 	struct snd_info_entry *entry;
489 
490 	data = file->private_data;
491 	if (data == NULL)
492 		return 0;
493 	entry = data->entry;
494 	switch (entry->content) {
495 	case SNDRV_INFO_CONTENT_DATA:
496 		if (entry->c.ops->mmap)
497 			return entry->c.ops->mmap(entry,
498 						  data->file_private_data,
499 						  inode, file, vma);
500 		break;
501 	}
502 	return -ENXIO;
503 }
504 
505 static const struct file_operations snd_info_entry_operations =
506 {
507 	.owner =		THIS_MODULE,
508 	.llseek =		snd_info_entry_llseek,
509 	.read =			snd_info_entry_read,
510 	.write =		snd_info_entry_write,
511 	.poll =			snd_info_entry_poll,
512 	.unlocked_ioctl =	snd_info_entry_ioctl,
513 	.mmap =			snd_info_entry_mmap,
514 	.open =			snd_info_entry_open,
515 	.release =		snd_info_entry_release,
516 };
517 
518 int __init snd_info_init(void)
519 {
520 	struct proc_dir_entry *p;
521 
522 	p = create_proc_entry("asound", S_IFDIR | S_IRUGO | S_IXUGO, NULL);
523 	if (p == NULL)
524 		return -ENOMEM;
525 	snd_proc_root = p;
526 #ifdef CONFIG_SND_OSSEMUL
527 	{
528 		struct snd_info_entry *entry;
529 		if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
530 			return -ENOMEM;
531 		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
532 		if (snd_info_register(entry) < 0) {
533 			snd_info_free_entry(entry);
534 			return -ENOMEM;
535 		}
536 		snd_oss_root = entry;
537 	}
538 #endif
539 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
540 	{
541 		struct snd_info_entry *entry;
542 		if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
543 			return -ENOMEM;
544 		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
545 		if (snd_info_register(entry) < 0) {
546 			snd_info_free_entry(entry);
547 			return -ENOMEM;
548 		}
549 		snd_seq_root = entry;
550 	}
551 #endif
552 	snd_info_version_init();
553 	snd_minor_info_init();
554 	snd_minor_info_oss_init();
555 	snd_card_info_init();
556 	return 0;
557 }
558 
559 int __exit snd_info_done(void)
560 {
561 	snd_card_info_done();
562 	snd_minor_info_oss_done();
563 	snd_minor_info_done();
564 	snd_info_version_done();
565 	if (snd_proc_root) {
566 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
567 		snd_info_free_entry(snd_seq_root);
568 #endif
569 #ifdef CONFIG_SND_OSSEMUL
570 		snd_info_free_entry(snd_oss_root);
571 #endif
572 		snd_remove_proc_entry(NULL, snd_proc_root);
573 	}
574 	return 0;
575 }
576 
577 /*
578 
579  */
580 
581 
582 /*
583  * create a card proc file
584  * called from init.c
585  */
586 int snd_info_card_create(struct snd_card *card)
587 {
588 	char str[8];
589 	struct snd_info_entry *entry;
590 
591 	if (snd_BUG_ON(!card))
592 		return -ENXIO;
593 
594 	sprintf(str, "card%i", card->number);
595 	if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
596 		return -ENOMEM;
597 	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
598 	if (snd_info_register(entry) < 0) {
599 		snd_info_free_entry(entry);
600 		return -ENOMEM;
601 	}
602 	card->proc_root = entry;
603 	return 0;
604 }
605 
606 /*
607  * register the card proc file
608  * called from init.c
609  */
610 int snd_info_card_register(struct snd_card *card)
611 {
612 	struct proc_dir_entry *p;
613 
614 	if (snd_BUG_ON(!card))
615 		return -ENXIO;
616 
617 	if (!strcmp(card->id, card->proc_root->name))
618 		return 0;
619 
620 	p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
621 	if (p == NULL)
622 		return -ENOMEM;
623 	card->proc_root_link = p;
624 	return 0;
625 }
626 
627 /*
628  * called on card->id change
629  */
630 void snd_info_card_id_change(struct snd_card *card)
631 {
632 	mutex_lock(&info_mutex);
633 	if (card->proc_root_link) {
634 		snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
635 		card->proc_root_link = NULL;
636 	}
637 	if (strcmp(card->id, card->proc_root->name))
638 		card->proc_root_link = proc_symlink(card->id,
639 						    snd_proc_root,
640 						    card->proc_root->name);
641 	mutex_unlock(&info_mutex);
642 }
643 
644 /*
645  * de-register the card proc file
646  * called from init.c
647  */
648 void snd_info_card_disconnect(struct snd_card *card)
649 {
650 	if (!card)
651 		return;
652 	mutex_lock(&info_mutex);
653 	if (card->proc_root_link) {
654 		snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
655 		card->proc_root_link = NULL;
656 	}
657 	if (card->proc_root)
658 		snd_info_disconnect(card->proc_root);
659 	mutex_unlock(&info_mutex);
660 }
661 
662 /*
663  * release the card proc file resources
664  * called from init.c
665  */
666 int snd_info_card_free(struct snd_card *card)
667 {
668 	if (!card)
669 		return 0;
670 	snd_info_free_entry(card->proc_root);
671 	card->proc_root = NULL;
672 	return 0;
673 }
674 
675 
676 /**
677  * snd_info_get_line - read one line from the procfs buffer
678  * @buffer: the procfs buffer
679  * @line: the buffer to store
680  * @len: the max. buffer size - 1
681  *
682  * Reads one line from the buffer and stores the string.
683  *
684  * Returns zero if successful, or 1 if error or EOF.
685  */
686 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
687 {
688 	int c = -1;
689 
690 	if (len <= 0 || buffer->stop || buffer->error)
691 		return 1;
692 	while (--len > 0) {
693 		c = buffer->buffer[buffer->curr++];
694 		if (c == '\n') {
695 			if (buffer->curr >= buffer->size)
696 				buffer->stop = 1;
697 			break;
698 		}
699 		*line++ = c;
700 		if (buffer->curr >= buffer->size) {
701 			buffer->stop = 1;
702 			break;
703 		}
704 	}
705 	while (c != '\n' && !buffer->stop) {
706 		c = buffer->buffer[buffer->curr++];
707 		if (buffer->curr >= buffer->size)
708 			buffer->stop = 1;
709 	}
710 	*line = '\0';
711 	return 0;
712 }
713 
714 EXPORT_SYMBOL(snd_info_get_line);
715 
716 /**
717  * snd_info_get_str - parse a string token
718  * @dest: the buffer to store the string token
719  * @src: the original string
720  * @len: the max. length of token - 1
721  *
722  * Parses the original string and copy a token to the given
723  * string buffer.
724  *
725  * Returns the updated pointer of the original string so that
726  * it can be used for the next call.
727  */
728 const char *snd_info_get_str(char *dest, const char *src, int len)
729 {
730 	int c;
731 
732 	while (*src == ' ' || *src == '\t')
733 		src++;
734 	if (*src == '"' || *src == '\'') {
735 		c = *src++;
736 		while (--len > 0 && *src && *src != c) {
737 			*dest++ = *src++;
738 		}
739 		if (*src == c)
740 			src++;
741 	} else {
742 		while (--len > 0 && *src && *src != ' ' && *src != '\t') {
743 			*dest++ = *src++;
744 		}
745 	}
746 	*dest = 0;
747 	while (*src == ' ' || *src == '\t')
748 		src++;
749 	return src;
750 }
751 
752 EXPORT_SYMBOL(snd_info_get_str);
753 
754 /**
755  * snd_info_create_entry - create an info entry
756  * @name: the proc file name
757  *
758  * Creates an info entry with the given file name and initializes as
759  * the default state.
760  *
761  * Usually called from other functions such as
762  * snd_info_create_card_entry().
763  *
764  * Returns the pointer of the new instance, or NULL on failure.
765  */
766 static struct snd_info_entry *snd_info_create_entry(const char *name)
767 {
768 	struct snd_info_entry *entry;
769 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
770 	if (entry == NULL)
771 		return NULL;
772 	entry->name = kstrdup(name, GFP_KERNEL);
773 	if (entry->name == NULL) {
774 		kfree(entry);
775 		return NULL;
776 	}
777 	entry->mode = S_IFREG | S_IRUGO;
778 	entry->content = SNDRV_INFO_CONTENT_TEXT;
779 	mutex_init(&entry->access);
780 	INIT_LIST_HEAD(&entry->children);
781 	INIT_LIST_HEAD(&entry->list);
782 	return entry;
783 }
784 
785 /**
786  * snd_info_create_module_entry - create an info entry for the given module
787  * @module: the module pointer
788  * @name: the file name
789  * @parent: the parent directory
790  *
791  * Creates a new info entry and assigns it to the given module.
792  *
793  * Returns the pointer of the new instance, or NULL on failure.
794  */
795 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
796 					       const char *name,
797 					       struct snd_info_entry *parent)
798 {
799 	struct snd_info_entry *entry = snd_info_create_entry(name);
800 	if (entry) {
801 		entry->module = module;
802 		entry->parent = parent;
803 	}
804 	return entry;
805 }
806 
807 EXPORT_SYMBOL(snd_info_create_module_entry);
808 
809 /**
810  * snd_info_create_card_entry - create an info entry for the given card
811  * @card: the card instance
812  * @name: the file name
813  * @parent: the parent directory
814  *
815  * Creates a new info entry and assigns it to the given card.
816  *
817  * Returns the pointer of the new instance, or NULL on failure.
818  */
819 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
820 					     const char *name,
821 					     struct snd_info_entry * parent)
822 {
823 	struct snd_info_entry *entry = snd_info_create_entry(name);
824 	if (entry) {
825 		entry->module = card->module;
826 		entry->card = card;
827 		entry->parent = parent;
828 	}
829 	return entry;
830 }
831 
832 EXPORT_SYMBOL(snd_info_create_card_entry);
833 
834 static void snd_info_disconnect(struct snd_info_entry *entry)
835 {
836 	struct list_head *p, *n;
837 	struct proc_dir_entry *root;
838 
839 	list_for_each_safe(p, n, &entry->children) {
840 		snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
841 	}
842 
843 	if (! entry->p)
844 		return;
845 	list_del_init(&entry->list);
846 	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
847 	snd_BUG_ON(!root);
848 	snd_remove_proc_entry(root, entry->p);
849 	entry->p = NULL;
850 }
851 
852 static int snd_info_dev_free_entry(struct snd_device *device)
853 {
854 	struct snd_info_entry *entry = device->device_data;
855 	snd_info_free_entry(entry);
856 	return 0;
857 }
858 
859 static int snd_info_dev_register_entry(struct snd_device *device)
860 {
861 	struct snd_info_entry *entry = device->device_data;
862 	return snd_info_register(entry);
863 }
864 
865 /**
866  * snd_card_proc_new - create an info entry for the given card
867  * @card: the card instance
868  * @name: the file name
869  * @entryp: the pointer to store the new info entry
870  *
871  * Creates a new info entry and assigns it to the given card.
872  * Unlike snd_info_create_card_entry(), this function registers the
873  * info entry as an ALSA device component, so that it can be
874  * unregistered/released without explicit call.
875  * Also, you don't have to register this entry via snd_info_register(),
876  * since this will be registered by snd_card_register() automatically.
877  *
878  * The parent is assumed as card->proc_root.
879  *
880  * For releasing this entry, use snd_device_free() instead of
881  * snd_info_free_entry().
882  *
883  * Returns zero if successful, or a negative error code on failure.
884  */
885 int snd_card_proc_new(struct snd_card *card, const char *name,
886 		      struct snd_info_entry **entryp)
887 {
888 	static struct snd_device_ops ops = {
889 		.dev_free = snd_info_dev_free_entry,
890 		.dev_register =	snd_info_dev_register_entry,
891 		/* disconnect is done via snd_info_card_disconnect() */
892 	};
893 	struct snd_info_entry *entry;
894 	int err;
895 
896 	entry = snd_info_create_card_entry(card, name, card->proc_root);
897 	if (! entry)
898 		return -ENOMEM;
899 	if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
900 		snd_info_free_entry(entry);
901 		return err;
902 	}
903 	if (entryp)
904 		*entryp = entry;
905 	return 0;
906 }
907 
908 EXPORT_SYMBOL(snd_card_proc_new);
909 
910 /**
911  * snd_info_free_entry - release the info entry
912  * @entry: the info entry
913  *
914  * Releases the info entry.  Don't call this after registered.
915  */
916 void snd_info_free_entry(struct snd_info_entry * entry)
917 {
918 	if (entry == NULL)
919 		return;
920 	if (entry->p) {
921 		mutex_lock(&info_mutex);
922 		snd_info_disconnect(entry);
923 		mutex_unlock(&info_mutex);
924 	}
925 	kfree(entry->name);
926 	if (entry->private_free)
927 		entry->private_free(entry);
928 	kfree(entry);
929 }
930 
931 EXPORT_SYMBOL(snd_info_free_entry);
932 
933 /**
934  * snd_info_register - register the info entry
935  * @entry: the info entry
936  *
937  * Registers the proc info entry.
938  *
939  * Returns zero if successful, or a negative error code on failure.
940  */
941 int snd_info_register(struct snd_info_entry * entry)
942 {
943 	struct proc_dir_entry *root, *p = NULL;
944 
945 	if (snd_BUG_ON(!entry))
946 		return -ENXIO;
947 	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
948 	mutex_lock(&info_mutex);
949 	p = create_proc_entry(entry->name, entry->mode, root);
950 	if (!p) {
951 		mutex_unlock(&info_mutex);
952 		return -ENOMEM;
953 	}
954 	if (!S_ISDIR(entry->mode))
955 		p->proc_fops = &snd_info_entry_operations;
956 	p->size = entry->size;
957 	p->data = entry;
958 	entry->p = p;
959 	if (entry->parent)
960 		list_add_tail(&entry->list, &entry->parent->children);
961 	mutex_unlock(&info_mutex);
962 	return 0;
963 }
964 
965 EXPORT_SYMBOL(snd_info_register);
966 
967 /*
968 
969  */
970 
971 static struct snd_info_entry *snd_info_version_entry;
972 
973 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
974 {
975 	snd_iprintf(buffer,
976 		    "Advanced Linux Sound Architecture Driver Version "
977 		    CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
978 		   );
979 }
980 
981 static int __init snd_info_version_init(void)
982 {
983 	struct snd_info_entry *entry;
984 
985 	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
986 	if (entry == NULL)
987 		return -ENOMEM;
988 	entry->c.text.read = snd_info_version_read;
989 	if (snd_info_register(entry) < 0) {
990 		snd_info_free_entry(entry);
991 		return -ENOMEM;
992 	}
993 	snd_info_version_entry = entry;
994 	return 0;
995 }
996 
997 static int __exit snd_info_version_done(void)
998 {
999 	snd_info_free_entry(snd_info_version_entry);
1000 	return 0;
1001 }
1002 
1003 #endif /* CONFIG_PROC_FS */
1004