ALSA: info - Implement common llseek for binary mode
[linux-2.6.git] / sound / core / info.c
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/slab.h>
26 #include <linux/smp_lock.h>
27 #include <linux/string.h>
28 #include <sound/core.h>
29 #include <sound/minors.h>
30 #include <sound/info.h>
31 #include <sound/version.h>
32 #include <linux/proc_fs.h>
33 #include <linux/mutex.h>
34 #include <stdarg.h>
35
36 /*
37  *
38  */
39
40 #ifdef CONFIG_PROC_FS
41
42 int snd_info_check_reserved_words(const char *str)
43 {
44         static char *reserved[] =
45         {
46                 "version",
47                 "meminfo",
48                 "memdebug",
49                 "detect",
50                 "devices",
51                 "oss",
52                 "cards",
53                 "timers",
54                 "synth",
55                 "pcm",
56                 "seq",
57                 NULL
58         };
59         char **xstr = reserved;
60
61         while (*xstr) {
62                 if (!strcmp(*xstr, str))
63                         return 0;
64                 xstr++;
65         }
66         if (!strncmp(str, "card", 4))
67                 return 0;
68         return 1;
69 }
70
71 static DEFINE_MUTEX(info_mutex);
72
73 struct snd_info_private_data {
74         struct snd_info_buffer *rbuffer;
75         struct snd_info_buffer *wbuffer;
76         struct snd_info_entry *entry;
77         void *file_private_data;
78 };
79
80 static int snd_info_version_init(void);
81 static int snd_info_version_done(void);
82 static void snd_info_disconnect(struct snd_info_entry *entry);
83
84
85 /* resize the proc r/w buffer */
86 static int resize_info_buffer(struct snd_info_buffer *buffer,
87                               unsigned int nsize)
88 {
89         char *nbuf;
90
91         nsize = PAGE_ALIGN(nsize);
92         nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL);
93         if (! nbuf)
94                 return -ENOMEM;
95
96         buffer->buffer = nbuf;
97         buffer->len = nsize;
98         return 0;
99 }
100
101 /**
102  * snd_iprintf - printf on the procfs buffer
103  * @buffer: the procfs buffer
104  * @fmt: the printf format
105  *
106  * Outputs the string on the procfs buffer just like printf().
107  *
108  * Returns the size of output string.
109  */
110 int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
111 {
112         va_list args;
113         int len, res;
114         int err = 0;
115
116         might_sleep();
117         if (buffer->stop || buffer->error)
118                 return 0;
119         len = buffer->len - buffer->size;
120         va_start(args, fmt);
121         for (;;) {
122                 va_list ap;
123                 va_copy(ap, args);
124                 res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
125                 va_end(ap);
126                 if (res < len)
127                         break;
128                 err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
129                 if (err < 0)
130                         break;
131                 len = buffer->len - buffer->size;
132         }
133         va_end(args);
134
135         if (err < 0)
136                 return err;
137         buffer->curr += res;
138         buffer->size += res;
139         return res;
140 }
141
142 EXPORT_SYMBOL(snd_iprintf);
143
144 /*
145
146  */
147
148 static struct proc_dir_entry *snd_proc_root;
149 struct snd_info_entry *snd_seq_root;
150 EXPORT_SYMBOL(snd_seq_root);
151
152 #ifdef CONFIG_SND_OSSEMUL
153 struct snd_info_entry *snd_oss_root;
154 #endif
155
156 static void snd_remove_proc_entry(struct proc_dir_entry *parent,
157                                   struct proc_dir_entry *de)
158 {
159         if (de)
160                 remove_proc_entry(de->name, parent);
161 }
162
163 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
164 {
165         struct snd_info_private_data *data;
166         struct snd_info_entry *entry;
167         loff_t ret = -EINVAL, size;
168
169         data = file->private_data;
170         entry = data->entry;
171         mutex_lock(&entry->access);
172         if (entry->content == SNDRV_INFO_CONTENT_DATA &&
173             entry->c.ops->llseek) {
174                 offset = entry->c.ops->llseek(entry,
175                                               data->file_private_data,
176                                               file, offset, orig);
177                 goto out;
178         }
179         if (entry->content == SNDRV_INFO_CONTENT_DATA)
180                 size = entry->size;
181         else
182                 size = 0;
183         switch (orig) {
184         case SEEK_SET:
185                 break;
186         case SEEK_CUR:
187                 offset += file->f_pos;
188                 break;
189         case SEEK_END:
190                 if (!size)
191                         goto out;
192                 offset += size;
193                 break;
194         default:
195                 goto out;
196         }
197         if (offset < 0)
198                 goto out;
199         if (size && offset > size)
200                 offset = size;
201         file->f_pos = offset;
202         ret = offset;
203  out:
204         mutex_unlock(&entry->access);
205         return ret;
206 }
207
208 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
209                                    size_t count, loff_t * offset)
210 {
211         struct snd_info_private_data *data;
212         struct snd_info_entry *entry;
213         struct snd_info_buffer *buf;
214         size_t size = 0;
215         loff_t pos;
216
217         data = file->private_data;
218         if (snd_BUG_ON(!data))
219                 return -ENXIO;
220         pos = *offset;
221         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
222                 return -EIO;
223         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
224                 return -EIO;
225         entry = data->entry;
226         switch (entry->content) {
227         case SNDRV_INFO_CONTENT_TEXT:
228                 buf = data->rbuffer;
229                 if (buf == NULL)
230                         return -EIO;
231                 if (pos >= buf->size)
232                         return 0;
233                 size = buf->size - pos;
234                 size = min(count, size);
235                 if (copy_to_user(buffer, buf->buffer + pos, size))
236                         return -EFAULT;
237                 break;
238         case SNDRV_INFO_CONTENT_DATA:
239                 if (pos >= entry->size)
240                         return 0;
241                 if (entry->c.ops->read) {
242                         size = entry->size - pos;
243                         size = min(count, size);
244                         size = entry->c.ops->read(entry,
245                                                   data->file_private_data,
246                                                   file, buffer, size, pos);
247                 }
248                 break;
249         }
250         if ((ssize_t) size > 0)
251                 *offset = pos + size;
252         return size;
253 }
254
255 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
256                                     size_t count, loff_t * offset)
257 {
258         struct snd_info_private_data *data;
259         struct snd_info_entry *entry;
260         struct snd_info_buffer *buf;
261         ssize_t size = 0;
262         loff_t pos;
263
264         data = file->private_data;
265         if (snd_BUG_ON(!data))
266                 return -ENXIO;
267         entry = data->entry;
268         pos = *offset;
269         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
270                 return -EIO;
271         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
272                 return -EIO;
273         switch (entry->content) {
274         case SNDRV_INFO_CONTENT_TEXT:
275                 buf = data->wbuffer;
276                 if (buf == NULL)
277                         return -EIO;
278                 mutex_lock(&entry->access);
279                 if (pos + count >= buf->len) {
280                         if (resize_info_buffer(buf, pos + count)) {
281                                 mutex_unlock(&entry->access);
282                                 return -ENOMEM;
283                         }
284                 }
285                 if (copy_from_user(buf->buffer + pos, buffer, count)) {
286                         mutex_unlock(&entry->access);
287                         return -EFAULT;
288                 }
289                 buf->size = pos + count;
290                 mutex_unlock(&entry->access);
291                 size = count;
292                 break;
293         case SNDRV_INFO_CONTENT_DATA:
294                 if (entry->c.ops->write && count > 0) {
295                         size_t maxsize = entry->size - pos;
296                         count = min(count, maxsize);
297                         size = entry->c.ops->write(entry,
298                                                    data->file_private_data,
299                                                    file, buffer, count, pos);
300                 }
301                 break;
302         }
303         if ((ssize_t) size > 0)
304                 *offset = pos + size;
305         return size;
306 }
307
308 static int snd_info_entry_open(struct inode *inode, struct file *file)
309 {
310         struct snd_info_entry *entry;
311         struct snd_info_private_data *data;
312         struct snd_info_buffer *buffer;
313         struct proc_dir_entry *p;
314         int mode, err;
315
316         mutex_lock(&info_mutex);
317         p = PDE(inode);
318         entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
319         if (entry == NULL || ! entry->p) {
320                 mutex_unlock(&info_mutex);
321                 return -ENODEV;
322         }
323         if (!try_module_get(entry->module)) {
324                 err = -EFAULT;
325                 goto __error1;
326         }
327         mode = file->f_flags & O_ACCMODE;
328         if (mode == O_RDONLY || mode == O_RDWR) {
329                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
330                      entry->c.ops->read == NULL)) {
331                         err = -ENODEV;
332                         goto __error;
333                 }
334         }
335         if (mode == O_WRONLY || mode == O_RDWR) {
336                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
337                      entry->c.ops->write == NULL)) {
338                         err = -ENODEV;
339                         goto __error;
340                 }
341         }
342         data = kzalloc(sizeof(*data), GFP_KERNEL);
343         if (data == NULL) {
344                 err = -ENOMEM;
345                 goto __error;
346         }
347         data->entry = entry;
348         switch (entry->content) {
349         case SNDRV_INFO_CONTENT_TEXT:
350                 if (mode == O_RDONLY || mode == O_RDWR) {
351                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
352                         if (buffer == NULL)
353                                 goto __nomem;
354                         data->rbuffer = buffer;
355                         buffer->len = PAGE_SIZE;
356                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
357                         if (buffer->buffer == NULL)
358                                 goto __nomem;
359                 }
360                 if (mode == O_WRONLY || mode == O_RDWR) {
361                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
362                         if (buffer == NULL)
363                                 goto __nomem;
364                         data->wbuffer = buffer;
365                         buffer->len = PAGE_SIZE;
366                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
367                         if (buffer->buffer == NULL)
368                                 goto __nomem;
369                 }
370                 break;
371         case SNDRV_INFO_CONTENT_DATA:   /* data */
372                 if (entry->c.ops->open) {
373                         if ((err = entry->c.ops->open(entry, mode,
374                                                       &data->file_private_data)) < 0) {
375                                 kfree(data);
376                                 goto __error;
377                         }
378                 }
379                 break;
380         }
381         file->private_data = data;
382         mutex_unlock(&info_mutex);
383         if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
384             (mode == O_RDONLY || mode == O_RDWR)) {
385                 if (entry->c.text.read) {
386                         mutex_lock(&entry->access);
387                         entry->c.text.read(entry, data->rbuffer);
388                         mutex_unlock(&entry->access);
389                 }
390         }
391         return 0;
392
393  __nomem:
394         if (data->rbuffer) {
395                 kfree(data->rbuffer->buffer);
396                 kfree(data->rbuffer);
397         }
398         if (data->wbuffer) {
399                 kfree(data->wbuffer->buffer);
400                 kfree(data->wbuffer);
401         }
402         kfree(data);
403         err = -ENOMEM;
404       __error:
405         module_put(entry->module);
406       __error1:
407         mutex_unlock(&info_mutex);
408         return err;
409 }
410
411 static int snd_info_entry_release(struct inode *inode, struct file *file)
412 {
413         struct snd_info_entry *entry;
414         struct snd_info_private_data *data;
415         int mode;
416
417         mode = file->f_flags & O_ACCMODE;
418         data = file->private_data;
419         entry = data->entry;
420         switch (entry->content) {
421         case SNDRV_INFO_CONTENT_TEXT:
422                 if (data->rbuffer) {
423                         kfree(data->rbuffer->buffer);
424                         kfree(data->rbuffer);
425                 }
426                 if (data->wbuffer) {
427                         if (entry->c.text.write) {
428                                 entry->c.text.write(entry, data->wbuffer);
429                                 if (data->wbuffer->error) {
430                                         snd_printk(KERN_WARNING "data write error to %s (%i)\n",
431                                                 entry->name,
432                                                 data->wbuffer->error);
433                                 }
434                         }
435                         kfree(data->wbuffer->buffer);
436                         kfree(data->wbuffer);
437                 }
438                 break;
439         case SNDRV_INFO_CONTENT_DATA:
440                 if (entry->c.ops->release)
441                         entry->c.ops->release(entry, mode,
442                                               data->file_private_data);
443                 break;
444         }
445         module_put(entry->module);
446         kfree(data);
447         return 0;
448 }
449
450 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
451 {
452         struct snd_info_private_data *data;
453         struct snd_info_entry *entry;
454         unsigned int mask;
455
456         data = file->private_data;
457         if (data == NULL)
458                 return 0;
459         entry = data->entry;
460         mask = 0;
461         switch (entry->content) {
462         case SNDRV_INFO_CONTENT_DATA:
463                 if (entry->c.ops->poll)
464                         return entry->c.ops->poll(entry,
465                                                   data->file_private_data,
466                                                   file, wait);
467                 if (entry->c.ops->read)
468                         mask |= POLLIN | POLLRDNORM;
469                 if (entry->c.ops->write)
470                         mask |= POLLOUT | POLLWRNORM;
471                 break;
472         }
473         return mask;
474 }
475
476 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
477                                 unsigned long arg)
478 {
479         struct snd_info_private_data *data;
480         struct snd_info_entry *entry;
481
482         data = file->private_data;
483         if (data == NULL)
484                 return 0;
485         entry = data->entry;
486         switch (entry->content) {
487         case SNDRV_INFO_CONTENT_DATA:
488                 if (entry->c.ops->ioctl)
489                         return entry->c.ops->ioctl(entry,
490                                                    data->file_private_data,
491                                                    file, cmd, arg);
492                 break;
493         }
494         return -ENOTTY;
495 }
496
497 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
498 {
499         struct inode *inode = file->f_path.dentry->d_inode;
500         struct snd_info_private_data *data;
501         struct snd_info_entry *entry;
502
503         data = file->private_data;
504         if (data == NULL)
505                 return 0;
506         entry = data->entry;
507         switch (entry->content) {
508         case SNDRV_INFO_CONTENT_DATA:
509                 if (entry->c.ops->mmap)
510                         return entry->c.ops->mmap(entry,
511                                                   data->file_private_data,
512                                                   inode, file, vma);
513                 break;
514         }
515         return -ENXIO;
516 }
517
518 static const struct file_operations snd_info_entry_operations =
519 {
520         .owner =                THIS_MODULE,
521         .llseek =               snd_info_entry_llseek,
522         .read =                 snd_info_entry_read,
523         .write =                snd_info_entry_write,
524         .poll =                 snd_info_entry_poll,
525         .unlocked_ioctl =       snd_info_entry_ioctl,
526         .mmap =                 snd_info_entry_mmap,
527         .open =                 snd_info_entry_open,
528         .release =              snd_info_entry_release,
529 };
530
531 int __init snd_info_init(void)
532 {
533         struct proc_dir_entry *p;
534
535         p = create_proc_entry("asound", S_IFDIR | S_IRUGO | S_IXUGO, NULL);
536         if (p == NULL)
537                 return -ENOMEM;
538         snd_proc_root = p;
539 #ifdef CONFIG_SND_OSSEMUL
540         {
541                 struct snd_info_entry *entry;
542                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", 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_oss_root = entry;
550         }
551 #endif
552 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
553         {
554                 struct snd_info_entry *entry;
555                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", 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_seq_root = entry;
563         }
564 #endif
565         snd_info_version_init();
566         snd_minor_info_init();
567         snd_minor_info_oss_init();
568         snd_card_info_init();
569         return 0;
570 }
571
572 int __exit snd_info_done(void)
573 {
574         snd_card_info_done();
575         snd_minor_info_oss_done();
576         snd_minor_info_done();
577         snd_info_version_done();
578         if (snd_proc_root) {
579 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
580                 snd_info_free_entry(snd_seq_root);
581 #endif
582 #ifdef CONFIG_SND_OSSEMUL
583                 snd_info_free_entry(snd_oss_root);
584 #endif
585                 snd_remove_proc_entry(NULL, snd_proc_root);
586         }
587         return 0;
588 }
589
590 /*
591
592  */
593
594
595 /*
596  * create a card proc file
597  * called from init.c
598  */
599 int snd_info_card_create(struct snd_card *card)
600 {
601         char str[8];
602         struct snd_info_entry *entry;
603
604         if (snd_BUG_ON(!card))
605                 return -ENXIO;
606
607         sprintf(str, "card%i", card->number);
608         if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
609                 return -ENOMEM;
610         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
611         if (snd_info_register(entry) < 0) {
612                 snd_info_free_entry(entry);
613                 return -ENOMEM;
614         }
615         card->proc_root = entry;
616         return 0;
617 }
618
619 /*
620  * register the card proc file
621  * called from init.c
622  */
623 int snd_info_card_register(struct snd_card *card)
624 {
625         struct proc_dir_entry *p;
626
627         if (snd_BUG_ON(!card))
628                 return -ENXIO;
629
630         if (!strcmp(card->id, card->proc_root->name))
631                 return 0;
632
633         p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
634         if (p == NULL)
635                 return -ENOMEM;
636         card->proc_root_link = p;
637         return 0;
638 }
639
640 /*
641  * called on card->id change
642  */
643 void snd_info_card_id_change(struct snd_card *card)
644 {
645         mutex_lock(&info_mutex);
646         if (card->proc_root_link) {
647                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
648                 card->proc_root_link = NULL;
649         }
650         if (strcmp(card->id, card->proc_root->name))
651                 card->proc_root_link = proc_symlink(card->id,
652                                                     snd_proc_root,
653                                                     card->proc_root->name);
654         mutex_unlock(&info_mutex);
655 }
656
657 /*
658  * de-register the card proc file
659  * called from init.c
660  */
661 void snd_info_card_disconnect(struct snd_card *card)
662 {
663         if (!card)
664                 return;
665         mutex_lock(&info_mutex);
666         if (card->proc_root_link) {
667                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
668                 card->proc_root_link = NULL;
669         }
670         if (card->proc_root)
671                 snd_info_disconnect(card->proc_root);
672         mutex_unlock(&info_mutex);
673 }
674
675 /*
676  * release the card proc file resources
677  * called from init.c
678  */
679 int snd_info_card_free(struct snd_card *card)
680 {
681         if (!card)
682                 return 0;
683         snd_info_free_entry(card->proc_root);
684         card->proc_root = NULL;
685         return 0;
686 }
687
688
689 /**
690  * snd_info_get_line - read one line from the procfs buffer
691  * @buffer: the procfs buffer
692  * @line: the buffer to store
693  * @len: the max. buffer size - 1
694  *
695  * Reads one line from the buffer and stores the string.
696  *
697  * Returns zero if successful, or 1 if error or EOF.
698  */
699 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
700 {
701         int c = -1;
702
703         if (len <= 0 || buffer->stop || buffer->error)
704                 return 1;
705         while (--len > 0) {
706                 c = buffer->buffer[buffer->curr++];
707                 if (c == '\n') {
708                         if (buffer->curr >= buffer->size)
709                                 buffer->stop = 1;
710                         break;
711                 }
712                 *line++ = c;
713                 if (buffer->curr >= buffer->size) {
714                         buffer->stop = 1;
715                         break;
716                 }
717         }
718         while (c != '\n' && !buffer->stop) {
719                 c = buffer->buffer[buffer->curr++];
720                 if (buffer->curr >= buffer->size)
721                         buffer->stop = 1;
722         }
723         *line = '\0';
724         return 0;
725 }
726
727 EXPORT_SYMBOL(snd_info_get_line);
728
729 /**
730  * snd_info_get_str - parse a string token
731  * @dest: the buffer to store the string token
732  * @src: the original string
733  * @len: the max. length of token - 1
734  *
735  * Parses the original string and copy a token to the given
736  * string buffer.
737  *
738  * Returns the updated pointer of the original string so that
739  * it can be used for the next call.
740  */
741 const char *snd_info_get_str(char *dest, const char *src, int len)
742 {
743         int c;
744
745         while (*src == ' ' || *src == '\t')
746                 src++;
747         if (*src == '"' || *src == '\'') {
748                 c = *src++;
749                 while (--len > 0 && *src && *src != c) {
750                         *dest++ = *src++;
751                 }
752                 if (*src == c)
753                         src++;
754         } else {
755                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
756                         *dest++ = *src++;
757                 }
758         }
759         *dest = 0;
760         while (*src == ' ' || *src == '\t')
761                 src++;
762         return src;
763 }
764
765 EXPORT_SYMBOL(snd_info_get_str);
766
767 /**
768  * snd_info_create_entry - create an info entry
769  * @name: the proc file name
770  *
771  * Creates an info entry with the given file name and initializes as
772  * the default state.
773  *
774  * Usually called from other functions such as
775  * snd_info_create_card_entry().
776  *
777  * Returns the pointer of the new instance, or NULL on failure.
778  */
779 static struct snd_info_entry *snd_info_create_entry(const char *name)
780 {
781         struct snd_info_entry *entry;
782         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
783         if (entry == NULL)
784                 return NULL;
785         entry->name = kstrdup(name, GFP_KERNEL);
786         if (entry->name == NULL) {
787                 kfree(entry);
788                 return NULL;
789         }
790         entry->mode = S_IFREG | S_IRUGO;
791         entry->content = SNDRV_INFO_CONTENT_TEXT;
792         mutex_init(&entry->access);
793         INIT_LIST_HEAD(&entry->children);
794         INIT_LIST_HEAD(&entry->list);
795         return entry;
796 }
797
798 /**
799  * snd_info_create_module_entry - create an info entry for the given module
800  * @module: the module pointer
801  * @name: the file name
802  * @parent: the parent directory
803  *
804  * Creates a new info entry and assigns it to the given module.
805  *
806  * Returns the pointer of the new instance, or NULL on failure.
807  */
808 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
809                                                const char *name,
810                                                struct snd_info_entry *parent)
811 {
812         struct snd_info_entry *entry = snd_info_create_entry(name);
813         if (entry) {
814                 entry->module = module;
815                 entry->parent = parent;
816         }
817         return entry;
818 }
819
820 EXPORT_SYMBOL(snd_info_create_module_entry);
821
822 /**
823  * snd_info_create_card_entry - create an info entry for the given card
824  * @card: the card instance
825  * @name: the file name
826  * @parent: the parent directory
827  *
828  * Creates a new info entry and assigns it to the given card.
829  *
830  * Returns the pointer of the new instance, or NULL on failure.
831  */
832 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
833                                              const char *name,
834                                              struct snd_info_entry * parent)
835 {
836         struct snd_info_entry *entry = snd_info_create_entry(name);
837         if (entry) {
838                 entry->module = card->module;
839                 entry->card = card;
840                 entry->parent = parent;
841         }
842         return entry;
843 }
844
845 EXPORT_SYMBOL(snd_info_create_card_entry);
846
847 static void snd_info_disconnect(struct snd_info_entry *entry)
848 {
849         struct list_head *p, *n;
850         struct proc_dir_entry *root;
851
852         list_for_each_safe(p, n, &entry->children) {
853                 snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
854         }
855
856         if (! entry->p)
857                 return;
858         list_del_init(&entry->list);
859         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
860         snd_BUG_ON(!root);
861         snd_remove_proc_entry(root, entry->p);
862         entry->p = NULL;
863 }
864
865 static int snd_info_dev_free_entry(struct snd_device *device)
866 {
867         struct snd_info_entry *entry = device->device_data;
868         snd_info_free_entry(entry);
869         return 0;
870 }
871
872 static int snd_info_dev_register_entry(struct snd_device *device)
873 {
874         struct snd_info_entry *entry = device->device_data;
875         return snd_info_register(entry);
876 }
877
878 /**
879  * snd_card_proc_new - create an info entry for the given card
880  * @card: the card instance
881  * @name: the file name
882  * @entryp: the pointer to store the new info entry
883  *
884  * Creates a new info entry and assigns it to the given card.
885  * Unlike snd_info_create_card_entry(), this function registers the
886  * info entry as an ALSA device component, so that it can be
887  * unregistered/released without explicit call.
888  * Also, you don't have to register this entry via snd_info_register(),
889  * since this will be registered by snd_card_register() automatically.
890  *
891  * The parent is assumed as card->proc_root.
892  *
893  * For releasing this entry, use snd_device_free() instead of
894  * snd_info_free_entry(). 
895  *
896  * Returns zero if successful, or a negative error code on failure.
897  */
898 int snd_card_proc_new(struct snd_card *card, const char *name,
899                       struct snd_info_entry **entryp)
900 {
901         static struct snd_device_ops ops = {
902                 .dev_free = snd_info_dev_free_entry,
903                 .dev_register = snd_info_dev_register_entry,
904                 /* disconnect is done via snd_info_card_disconnect() */
905         };
906         struct snd_info_entry *entry;
907         int err;
908
909         entry = snd_info_create_card_entry(card, name, card->proc_root);
910         if (! entry)
911                 return -ENOMEM;
912         if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
913                 snd_info_free_entry(entry);
914                 return err;
915         }
916         if (entryp)
917                 *entryp = entry;
918         return 0;
919 }
920
921 EXPORT_SYMBOL(snd_card_proc_new);
922
923 /**
924  * snd_info_free_entry - release the info entry
925  * @entry: the info entry
926  *
927  * Releases the info entry.  Don't call this after registered.
928  */
929 void snd_info_free_entry(struct snd_info_entry * entry)
930 {
931         if (entry == NULL)
932                 return;
933         if (entry->p) {
934                 mutex_lock(&info_mutex);
935                 snd_info_disconnect(entry);
936                 mutex_unlock(&info_mutex);
937         }
938         kfree(entry->name);
939         if (entry->private_free)
940                 entry->private_free(entry);
941         kfree(entry);
942 }
943
944 EXPORT_SYMBOL(snd_info_free_entry);
945
946 /**
947  * snd_info_register - register the info entry
948  * @entry: the info entry
949  *
950  * Registers the proc info entry.
951  *
952  * Returns zero if successful, or a negative error code on failure.
953  */
954 int snd_info_register(struct snd_info_entry * entry)
955 {
956         struct proc_dir_entry *root, *p = NULL;
957
958         if (snd_BUG_ON(!entry))
959                 return -ENXIO;
960         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
961         mutex_lock(&info_mutex);
962         p = create_proc_entry(entry->name, entry->mode, root);
963         if (!p) {
964                 mutex_unlock(&info_mutex);
965                 return -ENOMEM;
966         }
967         if (!S_ISDIR(entry->mode))
968                 p->proc_fops = &snd_info_entry_operations;
969         p->size = entry->size;
970         p->data = entry;
971         entry->p = p;
972         if (entry->parent)
973                 list_add_tail(&entry->list, &entry->parent->children);
974         mutex_unlock(&info_mutex);
975         return 0;
976 }
977
978 EXPORT_SYMBOL(snd_info_register);
979
980 /*
981
982  */
983
984 static struct snd_info_entry *snd_info_version_entry;
985
986 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
987 {
988         snd_iprintf(buffer,
989                     "Advanced Linux Sound Architecture Driver Version "
990                     CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
991                    );
992 }
993
994 static int __init snd_info_version_init(void)
995 {
996         struct snd_info_entry *entry;
997
998         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
999         if (entry == NULL)
1000                 return -ENOMEM;
1001         entry->c.text.read = snd_info_version_read;
1002         if (snd_info_register(entry) < 0) {
1003                 snd_info_free_entry(entry);
1004                 return -ENOMEM;
1005         }
1006         snd_info_version_entry = entry;
1007         return 0;
1008 }
1009
1010 static int __exit snd_info_version_done(void)
1011 {
1012         snd_info_free_entry(snd_info_version_entry);
1013         return 0;
1014 }
1015
1016 #endif /* CONFIG_PROC_FS */