xref: /openbmc/linux/sound/core/info.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  *  Information interface for ALSA driver
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
23 #include <linux/init.h>
24 #include <linux/time.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 = kmalloc(nsize, GFP_KERNEL);
92 	if (! nbuf)
93 		return -ENOMEM;
94 
95 	memcpy(nbuf, buffer->buffer, buffer->len);
96 	kfree(buffer->buffer);
97 	buffer->buffer = nbuf;
98 	buffer->len = nsize;
99 	return 0;
100 }
101 
102 /**
103  * snd_iprintf - printf on the procfs buffer
104  * @buffer: the procfs buffer
105  * @fmt: the printf format
106  *
107  * Outputs the string on the procfs buffer just like printf().
108  *
109  * Returns the size of output string.
110  */
111 int snd_iprintf(struct snd_info_buffer *buffer, char *fmt,...)
112 {
113 	va_list args;
114 	int len, res;
115 	int err = 0;
116 
117 	might_sleep();
118 	if (buffer->stop || buffer->error)
119 		return 0;
120 	len = buffer->len - buffer->size;
121 	va_start(args, fmt);
122 	for (;;) {
123 		va_list ap;
124 		va_copy(ap, args);
125 		res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
126 		va_end(ap);
127 		if (res < len)
128 			break;
129 		err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
130 		if (err < 0)
131 			break;
132 		len = buffer->len - buffer->size;
133 	}
134 	va_end(args);
135 
136 	if (err < 0)
137 		return err;
138 	buffer->curr += res;
139 	buffer->size += res;
140 	return res;
141 }
142 
143 EXPORT_SYMBOL(snd_iprintf);
144 
145 /*
146 
147  */
148 
149 static struct proc_dir_entry *snd_proc_root;
150 struct snd_info_entry *snd_seq_root;
151 EXPORT_SYMBOL(snd_seq_root);
152 
153 #ifdef CONFIG_SND_OSSEMUL
154 struct snd_info_entry *snd_oss_root;
155 #endif
156 
157 static inline void snd_info_entry_prepare(struct proc_dir_entry *de)
158 {
159 	de->owner = THIS_MODULE;
160 }
161 
162 static void snd_remove_proc_entry(struct proc_dir_entry *parent,
163 				  struct proc_dir_entry *de)
164 {
165 	if (de)
166 		remove_proc_entry(de->name, parent);
167 }
168 
169 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
170 {
171 	struct snd_info_private_data *data;
172 	struct snd_info_entry *entry;
173 	loff_t ret;
174 
175 	data = file->private_data;
176 	entry = data->entry;
177 	lock_kernel();
178 	switch (entry->content) {
179 	case SNDRV_INFO_CONTENT_TEXT:
180 		switch (orig) {
181 		case SEEK_SET:
182 			file->f_pos = offset;
183 			ret = file->f_pos;
184 			goto out;
185 		case SEEK_CUR:
186 			file->f_pos += offset;
187 			ret = file->f_pos;
188 			goto out;
189 		case SEEK_END:
190 		default:
191 			ret = -EINVAL;
192 			goto out;
193 		}
194 		break;
195 	case SNDRV_INFO_CONTENT_DATA:
196 		if (entry->c.ops->llseek) {
197 			ret = entry->c.ops->llseek(entry,
198 						    data->file_private_data,
199 						    file, offset, orig);
200 			goto out;
201 		}
202 		break;
203 	}
204 	ret = -ENXIO;
205 out:
206 	unlock_kernel();
207 	return ret;
208 }
209 
210 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
211 				   size_t count, loff_t * offset)
212 {
213 	struct snd_info_private_data *data;
214 	struct snd_info_entry *entry;
215 	struct snd_info_buffer *buf;
216 	size_t size = 0;
217 	loff_t pos;
218 
219 	data = file->private_data;
220 	snd_assert(data != NULL, return -ENXIO);
221 	pos = *offset;
222 	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
223 		return -EIO;
224 	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
225 		return -EIO;
226 	entry = data->entry;
227 	switch (entry->content) {
228 	case SNDRV_INFO_CONTENT_TEXT:
229 		buf = data->rbuffer;
230 		if (buf == NULL)
231 			return -EIO;
232 		if (pos >= buf->size)
233 			return 0;
234 		size = buf->size - pos;
235 		size = min(count, size);
236 		if (copy_to_user(buffer, buf->buffer + pos, size))
237 			return -EFAULT;
238 		break;
239 	case SNDRV_INFO_CONTENT_DATA:
240 		if (entry->c.ops->read)
241 			size = entry->c.ops->read(entry,
242 						  data->file_private_data,
243 						  file, buffer, count, pos);
244 		break;
245 	}
246 	if ((ssize_t) size > 0)
247 		*offset = pos + size;
248 	return size;
249 }
250 
251 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
252 				    size_t count, loff_t * offset)
253 {
254 	struct snd_info_private_data *data;
255 	struct snd_info_entry *entry;
256 	struct snd_info_buffer *buf;
257 	ssize_t size = 0;
258 	loff_t pos;
259 
260 	data = file->private_data;
261 	snd_assert(data != NULL, return -ENXIO);
262 	entry = data->entry;
263 	pos = *offset;
264 	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
265 		return -EIO;
266 	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
267 		return -EIO;
268 	switch (entry->content) {
269 	case SNDRV_INFO_CONTENT_TEXT:
270 		buf = data->wbuffer;
271 		if (buf == NULL)
272 			return -EIO;
273 		mutex_lock(&entry->access);
274 		if (pos + count >= buf->len) {
275 			if (resize_info_buffer(buf, pos + count)) {
276 				mutex_unlock(&entry->access);
277 				return -ENOMEM;
278 			}
279 		}
280 		if (copy_from_user(buf->buffer + pos, buffer, count)) {
281 			mutex_unlock(&entry->access);
282 			return -EFAULT;
283 		}
284 		buf->size = pos + count;
285 		mutex_unlock(&entry->access);
286 		size = count;
287 		break;
288 	case SNDRV_INFO_CONTENT_DATA:
289 		if (entry->c.ops->write)
290 			size = entry->c.ops->write(entry,
291 						   data->file_private_data,
292 						   file, buffer, count, pos);
293 		break;
294 	}
295 	if ((ssize_t) size > 0)
296 		*offset = pos + size;
297 	return size;
298 }
299 
300 static int snd_info_entry_open(struct inode *inode, struct file *file)
301 {
302 	struct snd_info_entry *entry;
303 	struct snd_info_private_data *data;
304 	struct snd_info_buffer *buffer;
305 	struct proc_dir_entry *p;
306 	int mode, err;
307 
308 	mutex_lock(&info_mutex);
309 	p = PDE(inode);
310 	entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
311 	if (entry == NULL || ! entry->p) {
312 		mutex_unlock(&info_mutex);
313 		return -ENODEV;
314 	}
315 	if (!try_module_get(entry->module)) {
316 		err = -EFAULT;
317 		goto __error1;
318 	}
319 	mode = file->f_flags & O_ACCMODE;
320 	if (mode == O_RDONLY || mode == O_RDWR) {
321 		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
322 		     entry->c.ops->read == NULL)) {
323 		    	err = -ENODEV;
324 		    	goto __error;
325 		}
326 	}
327 	if (mode == O_WRONLY || mode == O_RDWR) {
328 		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
329 		     entry->c.ops->write == NULL)) {
330 		    	err = -ENODEV;
331 		    	goto __error;
332 		}
333 	}
334 	data = kzalloc(sizeof(*data), GFP_KERNEL);
335 	if (data == NULL) {
336 		err = -ENOMEM;
337 		goto __error;
338 	}
339 	data->entry = entry;
340 	switch (entry->content) {
341 	case SNDRV_INFO_CONTENT_TEXT:
342 		if (mode == O_RDONLY || mode == O_RDWR) {
343 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
344 			if (buffer == NULL)
345 				goto __nomem;
346 			data->rbuffer = buffer;
347 			buffer->len = PAGE_SIZE;
348 			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
349 			if (buffer->buffer == NULL)
350 				goto __nomem;
351 		}
352 		if (mode == O_WRONLY || mode == O_RDWR) {
353 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
354 			if (buffer == NULL)
355 				goto __nomem;
356 			data->wbuffer = buffer;
357 			buffer->len = PAGE_SIZE;
358 			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
359 			if (buffer->buffer == NULL)
360 				goto __nomem;
361 		}
362 		break;
363 	case SNDRV_INFO_CONTENT_DATA:	/* data */
364 		if (entry->c.ops->open) {
365 			if ((err = entry->c.ops->open(entry, mode,
366 						      &data->file_private_data)) < 0) {
367 				kfree(data);
368 				goto __error;
369 			}
370 		}
371 		break;
372 	}
373 	file->private_data = data;
374 	mutex_unlock(&info_mutex);
375 	if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
376 	    (mode == O_RDONLY || mode == O_RDWR)) {
377 		if (entry->c.text.read) {
378 			mutex_lock(&entry->access);
379 			entry->c.text.read(entry, data->rbuffer);
380 			mutex_unlock(&entry->access);
381 		}
382 	}
383 	return 0;
384 
385  __nomem:
386 	if (data->rbuffer) {
387 		kfree(data->rbuffer->buffer);
388 		kfree(data->rbuffer);
389 	}
390 	if (data->wbuffer) {
391 		kfree(data->wbuffer->buffer);
392 		kfree(data->wbuffer);
393 	}
394 	kfree(data);
395 	err = -ENOMEM;
396       __error:
397 	module_put(entry->module);
398       __error1:
399 	mutex_unlock(&info_mutex);
400 	return err;
401 }
402 
403 static int snd_info_entry_release(struct inode *inode, struct file *file)
404 {
405 	struct snd_info_entry *entry;
406 	struct snd_info_private_data *data;
407 	int mode;
408 
409 	mode = file->f_flags & O_ACCMODE;
410 	data = file->private_data;
411 	entry = data->entry;
412 	switch (entry->content) {
413 	case SNDRV_INFO_CONTENT_TEXT:
414 		if (data->rbuffer) {
415 			kfree(data->rbuffer->buffer);
416 			kfree(data->rbuffer);
417 		}
418 		if (data->wbuffer) {
419 			if (entry->c.text.write) {
420 				entry->c.text.write(entry, data->wbuffer);
421 				if (data->wbuffer->error) {
422 					snd_printk(KERN_WARNING "data write error to %s (%i)\n",
423 						entry->name,
424 						data->wbuffer->error);
425 				}
426 			}
427 			kfree(data->wbuffer->buffer);
428 			kfree(data->wbuffer);
429 		}
430 		break;
431 	case SNDRV_INFO_CONTENT_DATA:
432 		if (entry->c.ops->release)
433 			entry->c.ops->release(entry, mode,
434 					      data->file_private_data);
435 		break;
436 	}
437 	module_put(entry->module);
438 	kfree(data);
439 	return 0;
440 }
441 
442 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
443 {
444 	struct snd_info_private_data *data;
445 	struct snd_info_entry *entry;
446 	unsigned int mask;
447 
448 	data = file->private_data;
449 	if (data == NULL)
450 		return 0;
451 	entry = data->entry;
452 	mask = 0;
453 	switch (entry->content) {
454 	case SNDRV_INFO_CONTENT_DATA:
455 		if (entry->c.ops->poll)
456 			return entry->c.ops->poll(entry,
457 						  data->file_private_data,
458 						  file, wait);
459 		if (entry->c.ops->read)
460 			mask |= POLLIN | POLLRDNORM;
461 		if (entry->c.ops->write)
462 			mask |= POLLOUT | POLLWRNORM;
463 		break;
464 	}
465 	return mask;
466 }
467 
468 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
469 				unsigned long arg)
470 {
471 	struct snd_info_private_data *data;
472 	struct snd_info_entry *entry;
473 
474 	data = file->private_data;
475 	if (data == NULL)
476 		return 0;
477 	entry = data->entry;
478 	switch (entry->content) {
479 	case SNDRV_INFO_CONTENT_DATA:
480 		if (entry->c.ops->ioctl)
481 			return entry->c.ops->ioctl(entry,
482 						   data->file_private_data,
483 						   file, cmd, arg);
484 		break;
485 	}
486 	return -ENOTTY;
487 }
488 
489 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
490 {
491 	struct inode *inode = file->f_path.dentry->d_inode;
492 	struct snd_info_private_data *data;
493 	struct snd_info_entry *entry;
494 
495 	data = file->private_data;
496 	if (data == NULL)
497 		return 0;
498 	entry = data->entry;
499 	switch (entry->content) {
500 	case SNDRV_INFO_CONTENT_DATA:
501 		if (entry->c.ops->mmap)
502 			return entry->c.ops->mmap(entry,
503 						  data->file_private_data,
504 						  inode, file, vma);
505 		break;
506 	}
507 	return -ENXIO;
508 }
509 
510 static const struct file_operations snd_info_entry_operations =
511 {
512 	.owner =		THIS_MODULE,
513 	.llseek =		snd_info_entry_llseek,
514 	.read =			snd_info_entry_read,
515 	.write =		snd_info_entry_write,
516 	.poll =			snd_info_entry_poll,
517 	.unlocked_ioctl =	snd_info_entry_ioctl,
518 	.mmap =			snd_info_entry_mmap,
519 	.open =			snd_info_entry_open,
520 	.release =		snd_info_entry_release,
521 };
522 
523 /**
524  * snd_create_proc_entry - create a procfs entry
525  * @name: the name of the proc file
526  * @mode: the file permission bits, S_Ixxx
527  * @parent: the parent proc-directory entry
528  *
529  * Creates a new proc file entry with the given name and permission
530  * on the given directory.
531  *
532  * Returns the pointer of new instance or NULL on failure.
533  */
534 static struct proc_dir_entry *snd_create_proc_entry(const char *name, mode_t mode,
535 						    struct proc_dir_entry *parent)
536 {
537 	struct proc_dir_entry *p;
538 	p = create_proc_entry(name, mode, parent);
539 	if (p)
540 		snd_info_entry_prepare(p);
541 	return p;
542 }
543 
544 int __init snd_info_init(void)
545 {
546 	struct proc_dir_entry *p;
547 
548 	p = snd_create_proc_entry("asound", S_IFDIR | S_IRUGO | S_IXUGO, &proc_root);
549 	if (p == NULL)
550 		return -ENOMEM;
551 	snd_proc_root = p;
552 #ifdef CONFIG_SND_OSSEMUL
553 	{
554 		struct snd_info_entry *entry;
555 		if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
556 			return -ENOMEM;
557 		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
558 		if (snd_info_register(entry) < 0) {
559 			snd_info_free_entry(entry);
560 			return -ENOMEM;
561 		}
562 		snd_oss_root = entry;
563 	}
564 #endif
565 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
566 	{
567 		struct snd_info_entry *entry;
568 		if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
569 			return -ENOMEM;
570 		entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
571 		if (snd_info_register(entry) < 0) {
572 			snd_info_free_entry(entry);
573 			return -ENOMEM;
574 		}
575 		snd_seq_root = entry;
576 	}
577 #endif
578 	snd_info_version_init();
579 	snd_minor_info_init();
580 	snd_minor_info_oss_init();
581 	snd_card_info_init();
582 	return 0;
583 }
584 
585 int __exit snd_info_done(void)
586 {
587 	snd_card_info_done();
588 	snd_minor_info_oss_done();
589 	snd_minor_info_done();
590 	snd_info_version_done();
591 	if (snd_proc_root) {
592 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
593 		snd_info_free_entry(snd_seq_root);
594 #endif
595 #ifdef CONFIG_SND_OSSEMUL
596 		snd_info_free_entry(snd_oss_root);
597 #endif
598 		snd_remove_proc_entry(&proc_root, snd_proc_root);
599 	}
600 	return 0;
601 }
602 
603 /*
604 
605  */
606 
607 
608 /*
609  * create a card proc file
610  * called from init.c
611  */
612 int snd_info_card_create(struct snd_card *card)
613 {
614 	char str[8];
615 	struct snd_info_entry *entry;
616 
617 	snd_assert(card != NULL, return -ENXIO);
618 
619 	sprintf(str, "card%i", card->number);
620 	if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
621 		return -ENOMEM;
622 	entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
623 	if (snd_info_register(entry) < 0) {
624 		snd_info_free_entry(entry);
625 		return -ENOMEM;
626 	}
627 	card->proc_root = entry;
628 	return 0;
629 }
630 
631 /*
632  * register the card proc file
633  * called from init.c
634  */
635 int snd_info_card_register(struct snd_card *card)
636 {
637 	struct proc_dir_entry *p;
638 
639 	snd_assert(card != NULL, return -ENXIO);
640 
641 	if (!strcmp(card->id, card->proc_root->name))
642 		return 0;
643 
644 	p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
645 	if (p == NULL)
646 		return -ENOMEM;
647 	card->proc_root_link = p;
648 	return 0;
649 }
650 
651 /*
652  * de-register the card proc file
653  * called from init.c
654  */
655 void snd_info_card_disconnect(struct snd_card *card)
656 {
657 	snd_assert(card != NULL, return);
658 	mutex_lock(&info_mutex);
659 	if (card->proc_root_link) {
660 		snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
661 		card->proc_root_link = NULL;
662 	}
663 	if (card->proc_root)
664 		snd_info_disconnect(card->proc_root);
665 	mutex_unlock(&info_mutex);
666 }
667 
668 /*
669  * release the card proc file resources
670  * called from init.c
671  */
672 int snd_info_card_free(struct snd_card *card)
673 {
674 	snd_assert(card != NULL, return -ENXIO);
675 	snd_info_free_entry(card->proc_root);
676 	card->proc_root = NULL;
677 	return 0;
678 }
679 
680 
681 /**
682  * snd_info_get_line - read one line from the procfs buffer
683  * @buffer: the procfs buffer
684  * @line: the buffer to store
685  * @len: the max. buffer size - 1
686  *
687  * Reads one line from the buffer and stores the string.
688  *
689  * Returns zero if successful, or 1 if error or EOF.
690  */
691 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
692 {
693 	int c = -1;
694 
695 	if (len <= 0 || buffer->stop || buffer->error)
696 		return 1;
697 	while (--len > 0) {
698 		c = buffer->buffer[buffer->curr++];
699 		if (c == '\n') {
700 			if (buffer->curr >= buffer->size)
701 				buffer->stop = 1;
702 			break;
703 		}
704 		*line++ = c;
705 		if (buffer->curr >= buffer->size) {
706 			buffer->stop = 1;
707 			break;
708 		}
709 	}
710 	while (c != '\n' && !buffer->stop) {
711 		c = buffer->buffer[buffer->curr++];
712 		if (buffer->curr >= buffer->size)
713 			buffer->stop = 1;
714 	}
715 	*line = '\0';
716 	return 0;
717 }
718 
719 EXPORT_SYMBOL(snd_info_get_line);
720 
721 /**
722  * snd_info_get_str - parse a string token
723  * @dest: the buffer to store the string token
724  * @src: the original string
725  * @len: the max. length of token - 1
726  *
727  * Parses the original string and copy a token to the given
728  * string buffer.
729  *
730  * Returns the updated pointer of the original string so that
731  * it can be used for the next call.
732  */
733 char *snd_info_get_str(char *dest, char *src, int len)
734 {
735 	int c;
736 
737 	while (*src == ' ' || *src == '\t')
738 		src++;
739 	if (*src == '"' || *src == '\'') {
740 		c = *src++;
741 		while (--len > 0 && *src && *src != c) {
742 			*dest++ = *src++;
743 		}
744 		if (*src == c)
745 			src++;
746 	} else {
747 		while (--len > 0 && *src && *src != ' ' && *src != '\t') {
748 			*dest++ = *src++;
749 		}
750 	}
751 	*dest = 0;
752 	while (*src == ' ' || *src == '\t')
753 		src++;
754 	return src;
755 }
756 
757 EXPORT_SYMBOL(snd_info_get_str);
758 
759 /**
760  * snd_info_create_entry - create an info entry
761  * @name: the proc file name
762  *
763  * Creates an info entry with the given file name and initializes as
764  * the default state.
765  *
766  * Usually called from other functions such as
767  * snd_info_create_card_entry().
768  *
769  * Returns the pointer of the new instance, or NULL on failure.
770  */
771 static struct snd_info_entry *snd_info_create_entry(const char *name)
772 {
773 	struct snd_info_entry *entry;
774 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
775 	if (entry == NULL)
776 		return NULL;
777 	entry->name = kstrdup(name, GFP_KERNEL);
778 	if (entry->name == NULL) {
779 		kfree(entry);
780 		return NULL;
781 	}
782 	entry->mode = S_IFREG | S_IRUGO;
783 	entry->content = SNDRV_INFO_CONTENT_TEXT;
784 	mutex_init(&entry->access);
785 	INIT_LIST_HEAD(&entry->children);
786 	INIT_LIST_HEAD(&entry->list);
787 	return entry;
788 }
789 
790 /**
791  * snd_info_create_module_entry - create an info entry for the given module
792  * @module: the module pointer
793  * @name: the file name
794  * @parent: the parent directory
795  *
796  * Creates a new info entry and assigns it to the given module.
797  *
798  * Returns the pointer of the new instance, or NULL on failure.
799  */
800 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
801 					       const char *name,
802 					       struct snd_info_entry *parent)
803 {
804 	struct snd_info_entry *entry = snd_info_create_entry(name);
805 	if (entry) {
806 		entry->module = module;
807 		entry->parent = parent;
808 	}
809 	return entry;
810 }
811 
812 EXPORT_SYMBOL(snd_info_create_module_entry);
813 
814 /**
815  * snd_info_create_card_entry - create an info entry for the given card
816  * @card: the card instance
817  * @name: the file name
818  * @parent: the parent directory
819  *
820  * Creates a new info entry and assigns it to the given card.
821  *
822  * Returns the pointer of the new instance, or NULL on failure.
823  */
824 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
825 					     const char *name,
826 					     struct snd_info_entry * parent)
827 {
828 	struct snd_info_entry *entry = snd_info_create_entry(name);
829 	if (entry) {
830 		entry->module = card->module;
831 		entry->card = card;
832 		entry->parent = parent;
833 	}
834 	return entry;
835 }
836 
837 EXPORT_SYMBOL(snd_info_create_card_entry);
838 
839 static void snd_info_disconnect(struct snd_info_entry *entry)
840 {
841 	struct list_head *p, *n;
842 	struct proc_dir_entry *root;
843 
844 	list_for_each_safe(p, n, &entry->children) {
845 		snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
846 	}
847 
848 	if (! entry->p)
849 		return;
850 	list_del_init(&entry->list);
851 	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
852 	snd_assert(root, return);
853 	snd_remove_proc_entry(root, entry->p);
854 	entry->p = NULL;
855 }
856 
857 static int snd_info_dev_free_entry(struct snd_device *device)
858 {
859 	struct snd_info_entry *entry = device->device_data;
860 	snd_info_free_entry(entry);
861 	return 0;
862 }
863 
864 static int snd_info_dev_register_entry(struct snd_device *device)
865 {
866 	struct snd_info_entry *entry = device->device_data;
867 	return snd_info_register(entry);
868 }
869 
870 /**
871  * snd_card_proc_new - create an info entry for the given card
872  * @card: the card instance
873  * @name: the file name
874  * @entryp: the pointer to store the new info entry
875  *
876  * Creates a new info entry and assigns it to the given card.
877  * Unlike snd_info_create_card_entry(), this function registers the
878  * info entry as an ALSA device component, so that it can be
879  * unregistered/released without explicit call.
880  * Also, you don't have to register this entry via snd_info_register(),
881  * since this will be registered by snd_card_register() automatically.
882  *
883  * The parent is assumed as card->proc_root.
884  *
885  * For releasing this entry, use snd_device_free() instead of
886  * snd_info_free_entry().
887  *
888  * Returns zero if successful, or a negative error code on failure.
889  */
890 int snd_card_proc_new(struct snd_card *card, const char *name,
891 		      struct snd_info_entry **entryp)
892 {
893 	static struct snd_device_ops ops = {
894 		.dev_free = snd_info_dev_free_entry,
895 		.dev_register =	snd_info_dev_register_entry,
896 		/* disconnect is done via snd_info_card_disconnect() */
897 	};
898 	struct snd_info_entry *entry;
899 	int err;
900 
901 	entry = snd_info_create_card_entry(card, name, card->proc_root);
902 	if (! entry)
903 		return -ENOMEM;
904 	if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
905 		snd_info_free_entry(entry);
906 		return err;
907 	}
908 	if (entryp)
909 		*entryp = entry;
910 	return 0;
911 }
912 
913 EXPORT_SYMBOL(snd_card_proc_new);
914 
915 /**
916  * snd_info_free_entry - release the info entry
917  * @entry: the info entry
918  *
919  * Releases the info entry.  Don't call this after registered.
920  */
921 void snd_info_free_entry(struct snd_info_entry * entry)
922 {
923 	if (entry == NULL)
924 		return;
925 	if (entry->p) {
926 		mutex_lock(&info_mutex);
927 		snd_info_disconnect(entry);
928 		mutex_unlock(&info_mutex);
929 	}
930 	kfree(entry->name);
931 	if (entry->private_free)
932 		entry->private_free(entry);
933 	kfree(entry);
934 }
935 
936 EXPORT_SYMBOL(snd_info_free_entry);
937 
938 /**
939  * snd_info_register - register the info entry
940  * @entry: the info entry
941  *
942  * Registers the proc info entry.
943  *
944  * Returns zero if successful, or a negative error code on failure.
945  */
946 int snd_info_register(struct snd_info_entry * entry)
947 {
948 	struct proc_dir_entry *root, *p = NULL;
949 
950 	snd_assert(entry != NULL, return -ENXIO);
951 	root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
952 	mutex_lock(&info_mutex);
953 	p = snd_create_proc_entry(entry->name, entry->mode, root);
954 	if (!p) {
955 		mutex_unlock(&info_mutex);
956 		return -ENOMEM;
957 	}
958 	p->owner = entry->module;
959 	if (!S_ISDIR(entry->mode))
960 		p->proc_fops = &snd_info_entry_operations;
961 	p->size = entry->size;
962 	p->data = entry;
963 	entry->p = p;
964 	if (entry->parent)
965 		list_add_tail(&entry->list, &entry->parent->children);
966 	mutex_unlock(&info_mutex);
967 	return 0;
968 }
969 
970 EXPORT_SYMBOL(snd_info_register);
971 
972 /*
973 
974  */
975 
976 static struct snd_info_entry *snd_info_version_entry;
977 
978 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
979 {
980 	snd_iprintf(buffer,
981 		    "Advanced Linux Sound Architecture Driver Version "
982 		    CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
983 		   );
984 }
985 
986 static int __init snd_info_version_init(void)
987 {
988 	struct snd_info_entry *entry;
989 
990 	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
991 	if (entry == NULL)
992 		return -ENOMEM;
993 	entry->c.text.read = snd_info_version_read;
994 	if (snd_info_register(entry) < 0) {
995 		snd_info_free_entry(entry);
996 		return -ENOMEM;
997 	}
998 	snd_info_version_entry = entry;
999 	return 0;
1000 }
1001 
1002 static int __exit snd_info_version_done(void)
1003 {
1004 	snd_info_free_entry(snd_info_version_entry);
1005 	return 0;
1006 }
1007 
1008 #endif /* CONFIG_PROC_FS */
1009