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spi: spi-fsl-qspi: Fix return value check of devm_ioremap() in probe
[linux/fpc-iii.git] / sound / core / info.c
blob8c6bc5241df50c55a66c35a8b4e9d8863664d5af
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Information interface for ALSA driver
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7 #include <linux/init.h>
8 #include <linux/time.h>
9 #include <linux/mm.h>
10 #include <linux/slab.h>
11 #include <linux/string.h>
12 #include <linux/module.h>
13 #include <sound/core.h>
14 #include <sound/minors.h>
15 #include <sound/info.h>
16 #include <linux/utsname.h>
17 #include <linux/proc_fs.h>
18 #include <linux/mutex.h>
19 #include <stdarg.h>
20
21 int snd_info_check_reserved_words(const char *str)
22 {
23 static const char * const reserved[] =
24 {
25 "version",
26 "meminfo",
27 "memdebug",
28 "detect",
29 "devices",
30 "oss",
31 "cards",
32 "timers",
33 "synth",
34 "pcm",
35 "seq",
36 NULL
37 };
38 const char * const *xstr = reserved;
39
40 while (*xstr) {
41 if (!strcmp(*xstr, str))
42 return 0;
43 xstr++;
44 }
45 if (!strncmp(str, "card", 4))
46 return 0;
47 return 1;
48 }
49
50 static DEFINE_MUTEX(info_mutex);
51
52 struct snd_info_private_data {
53 struct snd_info_buffer *rbuffer;
54 struct snd_info_buffer *wbuffer;
55 struct snd_info_entry *entry;
56 void *file_private_data;
57 };
58
59 static int snd_info_version_init(void);
60 static void snd_info_disconnect(struct snd_info_entry *entry);
61
62 /*
63
64 */
65
66 static struct snd_info_entry *snd_proc_root;
67 struct snd_info_entry *snd_seq_root;
68 EXPORT_SYMBOL(snd_seq_root);
69
70 #ifdef CONFIG_SND_OSSEMUL
71 struct snd_info_entry *snd_oss_root;
72 #endif
73
74 static int alloc_info_private(struct snd_info_entry *entry,
75 struct snd_info_private_data **ret)
76 {
77 struct snd_info_private_data *data;
78
79 if (!entry || !entry->p)
80 return -ENODEV;
81 if (!try_module_get(entry->module))
82 return -EFAULT;
83 data = kzalloc(sizeof(*data), GFP_KERNEL);
84 if (!data) {
85 module_put(entry->module);
86 return -ENOMEM;
87 }
88 data->entry = entry;
89 *ret = data;
90 return 0;
91 }
92
93 static bool valid_pos(loff_t pos, size_t count)
94 {
95 if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
96 return false;
97 if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
98 return false;
99 return true;
100 }
101
102 /*
103 * file ops for binary proc files
104 */
105 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
106 {
107 struct snd_info_private_data *data;
108 struct snd_info_entry *entry;
109 loff_t ret = -EINVAL, size;
110
111 data = file->private_data;
112 entry = data->entry;
113 mutex_lock(&entry->access);
114 if (entry->c.ops->llseek) {
115 offset = entry->c.ops->llseek(entry,
116 data->file_private_data,
117 file, offset, orig);
118 goto out;
119 }
120
121 size = entry->size;
122 switch (orig) {
123 case SEEK_SET:
124 break;
125 case SEEK_CUR:
126 offset += file->f_pos;
127 break;
128 case SEEK_END:
129 if (!size)
130 goto out;
131 offset += size;
132 break;
133 default:
134 goto out;
135 }
136 if (offset < 0)
137 goto out;
138 if (size && offset > size)
139 offset = size;
140 file->f_pos = offset;
141 ret = offset;
142 out:
143 mutex_unlock(&entry->access);
144 return ret;
145 }
146
147 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
148 size_t count, loff_t * offset)
149 {
150 struct snd_info_private_data *data = file->private_data;
151 struct snd_info_entry *entry = data->entry;
152 size_t size;
153 loff_t pos;
154
155 pos = *offset;
156 if (!valid_pos(pos, count))
157 return -EIO;
158 if (pos >= entry->size)
159 return 0;
160 size = entry->size - pos;
161 size = min(count, size);
162 size = entry->c.ops->read(entry, data->file_private_data,
163 file, buffer, size, pos);
164 if ((ssize_t) size > 0)
165 *offset = pos + size;
166 return size;
167 }
168
169 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
170 size_t count, loff_t * offset)
171 {
172 struct snd_info_private_data *data = file->private_data;
173 struct snd_info_entry *entry = data->entry;
174 ssize_t size = 0;
175 loff_t pos;
176
177 pos = *offset;
178 if (!valid_pos(pos, count))
179 return -EIO;
180 if (count > 0) {
181 size_t maxsize = entry->size - pos;
182 count = min(count, maxsize);
183 size = entry->c.ops->write(entry, data->file_private_data,
184 file, buffer, count, pos);
185 }
186 if (size > 0)
187 *offset = pos + size;
188 return size;
189 }
190
191 static __poll_t snd_info_entry_poll(struct file *file, poll_table *wait)
192 {
193 struct snd_info_private_data *data = file->private_data;
194 struct snd_info_entry *entry = data->entry;
195 __poll_t mask = 0;
196
197 if (entry->c.ops->poll)
198 return entry->c.ops->poll(entry,
199 data->file_private_data,
200 file, wait);
201 if (entry->c.ops->read)
202 mask |= EPOLLIN | EPOLLRDNORM;
203 if (entry->c.ops->write)
204 mask |= EPOLLOUT | EPOLLWRNORM;
205 return mask;
206 }
207
208 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
209 unsigned long arg)
210 {
211 struct snd_info_private_data *data = file->private_data;
212 struct snd_info_entry *entry = data->entry;
213
214 if (!entry->c.ops->ioctl)
215 return -ENOTTY;
216 return entry->c.ops->ioctl(entry, data->file_private_data,
217 file, cmd, arg);
218 }
219
220 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
221 {
222 struct inode *inode = file_inode(file);
223 struct snd_info_private_data *data;
224 struct snd_info_entry *entry;
225
226 data = file->private_data;
227 if (data == NULL)
228 return 0;
229 entry = data->entry;
230 if (!entry->c.ops->mmap)
231 return -ENXIO;
232 return entry->c.ops->mmap(entry, data->file_private_data,
233 inode, file, vma);
234 }
235
236 static int snd_info_entry_open(struct inode *inode, struct file *file)
237 {
238 struct snd_info_entry *entry = PDE_DATA(inode);
239 struct snd_info_private_data *data;
240 int mode, err;
241
242 mutex_lock(&info_mutex);
243 err = alloc_info_private(entry, &data);
244 if (err < 0)
245 goto unlock;
246
247 mode = file->f_flags & O_ACCMODE;
248 if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
249 ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
250 err = -ENODEV;
251 goto error;
252 }
253
254 if (entry->c.ops->open) {
255 err = entry->c.ops->open(entry, mode, &data->file_private_data);
256 if (err < 0)
257 goto error;
258 }
259
260 file->private_data = data;
261 mutex_unlock(&info_mutex);
262 return 0;
263
264 error:
265 kfree(data);
266 module_put(entry->module);
267 unlock:
268 mutex_unlock(&info_mutex);
269 return err;
270 }
271
272 static int snd_info_entry_release(struct inode *inode, struct file *file)
273 {
274 struct snd_info_private_data *data = file->private_data;
275 struct snd_info_entry *entry = data->entry;
276
277 if (entry->c.ops->release)
278 entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
279 data->file_private_data);
280 module_put(entry->module);
281 kfree(data);
282 return 0;
283 }
284
285 static const struct proc_ops snd_info_entry_operations =
286 {
287 .proc_lseek = snd_info_entry_llseek,
288 .proc_read = snd_info_entry_read,
289 .proc_write = snd_info_entry_write,
290 .proc_poll = snd_info_entry_poll,
291 .proc_ioctl = snd_info_entry_ioctl,
292 .proc_mmap = snd_info_entry_mmap,
293 .proc_open = snd_info_entry_open,
294 .proc_release = snd_info_entry_release,
295 };
296
297 /*
298 * file ops for text proc files
299 */
300 static ssize_t snd_info_text_entry_write(struct file *file,
301 const char __user *buffer,
302 size_t count, loff_t *offset)
303 {
304 struct seq_file *m = file->private_data;
305 struct snd_info_private_data *data = m->private;
306 struct snd_info_entry *entry = data->entry;
307 struct snd_info_buffer *buf;
308 loff_t pos;
309 size_t next;
310 int err = 0;
311
312 if (!entry->c.text.write)
313 return -EIO;
314 pos = *offset;
315 if (!valid_pos(pos, count))
316 return -EIO;
317 next = pos + count;
318 /* don't handle too large text inputs */
319 if (next > 16 * 1024)
320 return -EIO;
321 mutex_lock(&entry->access);
322 buf = data->wbuffer;
323 if (!buf) {
324 data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
325 if (!buf) {
326 err = -ENOMEM;
327 goto error;
328 }
329 }
330 if (next > buf->len) {
331 char *nbuf = kvzalloc(PAGE_ALIGN(next), GFP_KERNEL);
332 if (!nbuf) {
333 err = -ENOMEM;
334 goto error;
335 }
336 kvfree(buf->buffer);
337 buf->buffer = nbuf;
338 buf->len = PAGE_ALIGN(next);
339 }
340 if (copy_from_user(buf->buffer + pos, buffer, count)) {
341 err = -EFAULT;
342 goto error;
343 }
344 buf->size = next;
345 error:
346 mutex_unlock(&entry->access);
347 if (err < 0)
348 return err;
349 *offset = next;
350 return count;
351 }
352
353 static int snd_info_seq_show(struct seq_file *seq, void *p)
354 {
355 struct snd_info_private_data *data = seq->private;
356 struct snd_info_entry *entry = data->entry;
357
358 if (!entry->c.text.read) {
359 return -EIO;
360 } else {
361 data->rbuffer->buffer = (char *)seq; /* XXX hack! */
362 entry->c.text.read(entry, data->rbuffer);
363 }
364 return 0;
365 }
366
367 static int snd_info_text_entry_open(struct inode *inode, struct file *file)
368 {
369 struct snd_info_entry *entry = PDE_DATA(inode);
370 struct snd_info_private_data *data;
371 int err;
372
373 mutex_lock(&info_mutex);
374 err = alloc_info_private(entry, &data);
375 if (err < 0)
376 goto unlock;
377
378 data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
379 if (!data->rbuffer) {
380 err = -ENOMEM;
381 goto error;
382 }
383 if (entry->size)
384 err = single_open_size(file, snd_info_seq_show, data,
385 entry->size);
386 else
387 err = single_open(file, snd_info_seq_show, data);
388 if (err < 0)
389 goto error;
390 mutex_unlock(&info_mutex);
391 return 0;
392
393 error:
394 kfree(data->rbuffer);
395 kfree(data);
396 module_put(entry->module);
397 unlock:
398 mutex_unlock(&info_mutex);
399 return err;
400 }
401
402 static int snd_info_text_entry_release(struct inode *inode, struct file *file)
403 {
404 struct seq_file *m = file->private_data;
405 struct snd_info_private_data *data = m->private;
406 struct snd_info_entry *entry = data->entry;
407
408 if (data->wbuffer && entry->c.text.write)
409 entry->c.text.write(entry, data->wbuffer);
410
411 single_release(inode, file);
412 kfree(data->rbuffer);
413 if (data->wbuffer) {
414 kvfree(data->wbuffer->buffer);
415 kfree(data->wbuffer);
416 }
417
418 module_put(entry->module);
419 kfree(data);
420 return 0;
421 }
422
423 static const struct proc_ops snd_info_text_entry_ops =
424 {
425 .proc_open = snd_info_text_entry_open,
426 .proc_release = snd_info_text_entry_release,
427 .proc_write = snd_info_text_entry_write,
428 .proc_lseek = seq_lseek,
429 .proc_read = seq_read,
430 };
431
432 static struct snd_info_entry *create_subdir(struct module *mod,
433 const char *name)
434 {
435 struct snd_info_entry *entry;
436
437 entry = snd_info_create_module_entry(mod, name, NULL);
438 if (!entry)
439 return NULL;
440 entry->mode = S_IFDIR | 0555;
441 if (snd_info_register(entry) < 0) {
442 snd_info_free_entry(entry);
443 return NULL;
444 }
445 return entry;
446 }
447
448 static struct snd_info_entry *
449 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
450 struct module *module);
451
452 int __init snd_info_init(void)
453 {
454 snd_proc_root = snd_info_create_entry("asound", NULL, THIS_MODULE);
455 if (!snd_proc_root)
456 return -ENOMEM;
457 snd_proc_root->mode = S_IFDIR | 0555;
458 snd_proc_root->p = proc_mkdir("asound", NULL);
459 if (!snd_proc_root->p)
460 goto error;
461 #ifdef CONFIG_SND_OSSEMUL
462 snd_oss_root = create_subdir(THIS_MODULE, "oss");
463 if (!snd_oss_root)
464 goto error;
465 #endif
466 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
467 snd_seq_root = create_subdir(THIS_MODULE, "seq");
468 if (!snd_seq_root)
469 goto error;
470 #endif
471 if (snd_info_version_init() < 0 ||
472 snd_minor_info_init() < 0 ||
473 snd_minor_info_oss_init() < 0 ||
474 snd_card_info_init() < 0 ||
475 snd_info_minor_register() < 0)
476 goto error;
477 return 0;
478
479 error:
480 snd_info_free_entry(snd_proc_root);
481 return -ENOMEM;
482 }
483
484 int __exit snd_info_done(void)
485 {
486 snd_info_free_entry(snd_proc_root);
487 return 0;
488 }
489
490 static void snd_card_id_read(struct snd_info_entry *entry,
491 struct snd_info_buffer *buffer)
492 {
493 struct snd_card *card = entry->private_data;
494
495 snd_iprintf(buffer, "%s\n", card->id);
496 }
497
498 /*
499 * create a card proc file
500 * called from init.c
501 */
502 int snd_info_card_create(struct snd_card *card)
503 {
504 char str[8];
505 struct snd_info_entry *entry;
506
507 if (snd_BUG_ON(!card))
508 return -ENXIO;
509
510 sprintf(str, "card%i", card->number);
511 entry = create_subdir(card->module, str);
512 if (!entry)
513 return -ENOMEM;
514 card->proc_root = entry;
515
516 return snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
517 }
518
519 /*
520 * register the card proc file
521 * called from init.c
522 * can be called multiple times for reinitialization
523 */
524 int snd_info_card_register(struct snd_card *card)
525 {
526 struct proc_dir_entry *p;
527 int err;
528
529 if (snd_BUG_ON(!card))
530 return -ENXIO;
531
532 err = snd_info_register(card->proc_root);
533 if (err < 0)
534 return err;
535
536 if (!strcmp(card->id, card->proc_root->name))
537 return 0;
538
539 if (card->proc_root_link)
540 return 0;
541 p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
542 if (!p)
543 return -ENOMEM;
544 card->proc_root_link = p;
545 return 0;
546 }
547
548 /*
549 * called on card->id change
550 */
551 void snd_info_card_id_change(struct snd_card *card)
552 {
553 mutex_lock(&info_mutex);
554 if (card->proc_root_link) {
555 proc_remove(card->proc_root_link);
556 card->proc_root_link = NULL;
557 }
558 if (strcmp(card->id, card->proc_root->name))
559 card->proc_root_link = proc_symlink(card->id,
560 snd_proc_root->p,
561 card->proc_root->name);
562 mutex_unlock(&info_mutex);
563 }
564
565 /*
566 * de-register the card proc file
567 * called from init.c
568 */
569 void snd_info_card_disconnect(struct snd_card *card)
570 {
571 if (!card)
572 return;
573 mutex_lock(&info_mutex);
574 proc_remove(card->proc_root_link);
575 card->proc_root_link = NULL;
576 if (card->proc_root)
577 snd_info_disconnect(card->proc_root);
578 mutex_unlock(&info_mutex);
579 }
580
581 /*
582 * release the card proc file resources
583 * called from init.c
584 */
585 int snd_info_card_free(struct snd_card *card)
586 {
587 if (!card)
588 return 0;
589 snd_info_free_entry(card->proc_root);
590 card->proc_root = NULL;
591 return 0;
592 }
593
594
595 /**
596 * snd_info_get_line - read one line from the procfs buffer
597 * @buffer: the procfs buffer
598 * @line: the buffer to store
599 * @len: the max. buffer size
600 *
601 * Reads one line from the buffer and stores the string.
602 *
603 * Return: Zero if successful, or 1 if error or EOF.
604 */
605 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
606 {
607 int c;
608
609 if (snd_BUG_ON(!buffer || !buffer->buffer))
610 return 1;
611 if (len <= 0 || buffer->stop || buffer->error)
612 return 1;
613 while (!buffer->stop) {
614 c = buffer->buffer[buffer->curr++];
615 if (buffer->curr >= buffer->size)
616 buffer->stop = 1;
617 if (c == '\n')
618 break;
619 if (len > 1) {
620 len--;
621 *line++ = c;
622 }
623 }
624 *line = '\0';
625 return 0;
626 }
627 EXPORT_SYMBOL(snd_info_get_line);
628
629 /**
630 * snd_info_get_str - parse a string token
631 * @dest: the buffer to store the string token
632 * @src: the original string
633 * @len: the max. length of token - 1
634 *
635 * Parses the original string and copy a token to the given
636 * string buffer.
637 *
638 * Return: The updated pointer of the original string so that
639 * it can be used for the next call.
640 */
641 const char *snd_info_get_str(char *dest, const char *src, int len)
642 {
643 int c;
644
645 while (*src == ' ' || *src == '\t')
646 src++;
647 if (*src == '"' || *src == '\'') {
648 c = *src++;
649 while (--len > 0 && *src && *src != c) {
650 *dest++ = *src++;
651 }
652 if (*src == c)
653 src++;
654 } else {
655 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
656 *dest++ = *src++;
657 }
658 }
659 *dest = 0;
660 while (*src == ' ' || *src == '\t')
661 src++;
662 return src;
663 }
664 EXPORT_SYMBOL(snd_info_get_str);
665
666 /*
667 * snd_info_create_entry - create an info entry
668 * @name: the proc file name
669 * @parent: the parent directory
670 *
671 * Creates an info entry with the given file name and initializes as
672 * the default state.
673 *
674 * Usually called from other functions such as
675 * snd_info_create_card_entry().
676 *
677 * Return: The pointer of the new instance, or %NULL on failure.
678 */
679 static struct snd_info_entry *
680 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
681 struct module *module)
682 {
683 struct snd_info_entry *entry;
684 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
685 if (entry == NULL)
686 return NULL;
687 entry->name = kstrdup(name, GFP_KERNEL);
688 if (entry->name == NULL) {
689 kfree(entry);
690 return NULL;
691 }
692 entry->mode = S_IFREG | 0444;
693 entry->content = SNDRV_INFO_CONTENT_TEXT;
694 mutex_init(&entry->access);
695 INIT_LIST_HEAD(&entry->children);
696 INIT_LIST_HEAD(&entry->list);
697 entry->parent = parent;
698 entry->module = module;
699 if (parent) {
700 mutex_lock(&parent->access);
701 list_add_tail(&entry->list, &parent->children);
702 mutex_unlock(&parent->access);
703 }
704 return entry;
705 }
706
707 /**
708 * snd_info_create_module_entry - create an info entry for the given module
709 * @module: the module pointer
710 * @name: the file name
711 * @parent: the parent directory
712 *
713 * Creates a new info entry and assigns it to the given module.
714 *
715 * Return: The pointer of the new instance, or %NULL on failure.
716 */
717 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
718 const char *name,
719 struct snd_info_entry *parent)
720 {
721 if (!parent)
722 parent = snd_proc_root;
723 return snd_info_create_entry(name, parent, module);
724 }
725 EXPORT_SYMBOL(snd_info_create_module_entry);
726
727 /**
728 * snd_info_create_card_entry - create an info entry for the given card
729 * @card: the card instance
730 * @name: the file name
731 * @parent: the parent directory
732 *
733 * Creates a new info entry and assigns it to the given card.
734 *
735 * Return: The pointer of the new instance, or %NULL on failure.
736 */
737 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
738 const char *name,
739 struct snd_info_entry * parent)
740 {
741 if (!parent)
742 parent = card->proc_root;
743 return snd_info_create_entry(name, parent, card->module);
744 }
745 EXPORT_SYMBOL(snd_info_create_card_entry);
746
747 static void snd_info_disconnect(struct snd_info_entry *entry)
748 {
749 struct snd_info_entry *p;
750
751 if (!entry->p)
752 return;
753 list_for_each_entry(p, &entry->children, list)
754 snd_info_disconnect(p);
755 proc_remove(entry->p);
756 entry->p = NULL;
757 }
758
759 /**
760 * snd_info_free_entry - release the info entry
761 * @entry: the info entry
762 *
763 * Releases the info entry.
764 */
765 void snd_info_free_entry(struct snd_info_entry * entry)
766 {
767 struct snd_info_entry *p, *n;
768
769 if (!entry)
770 return;
771 if (entry->p) {
772 mutex_lock(&info_mutex);
773 snd_info_disconnect(entry);
774 mutex_unlock(&info_mutex);
775 }
776
777 /* free all children at first */
778 list_for_each_entry_safe(p, n, &entry->children, list)
779 snd_info_free_entry(p);
780
781 p = entry->parent;
782 if (p) {
783 mutex_lock(&p->access);
784 list_del(&entry->list);
785 mutex_unlock(&p->access);
786 }
787 kfree(entry->name);
788 if (entry->private_free)
789 entry->private_free(entry);
790 kfree(entry);
791 }
792 EXPORT_SYMBOL(snd_info_free_entry);
793
794 static int __snd_info_register(struct snd_info_entry *entry)
795 {
796 struct proc_dir_entry *root, *p = NULL;
797
798 if (snd_BUG_ON(!entry))
799 return -ENXIO;
800 root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
801 mutex_lock(&info_mutex);
802 if (entry->p || !root)
803 goto unlock;
804 if (S_ISDIR(entry->mode)) {
805 p = proc_mkdir_mode(entry->name, entry->mode, root);
806 if (!p) {
807 mutex_unlock(&info_mutex);
808 return -ENOMEM;
809 }
810 } else {
811 const struct proc_ops *ops;
812 if (entry->content == SNDRV_INFO_CONTENT_DATA)
813 ops = &snd_info_entry_operations;
814 else
815 ops = &snd_info_text_entry_ops;
816 p = proc_create_data(entry->name, entry->mode, root,
817 ops, entry);
818 if (!p) {
819 mutex_unlock(&info_mutex);
820 return -ENOMEM;
821 }
822 proc_set_size(p, entry->size);
823 }
824 entry->p = p;
825 unlock:
826 mutex_unlock(&info_mutex);
827 return 0;
828 }
829
830 /**
831 * snd_info_register - register the info entry
832 * @entry: the info entry
833 *
834 * Registers the proc info entry.
835 * The all children entries are registered recursively.
836 *
837 * Return: Zero if successful, or a negative error code on failure.
838 */
839 int snd_info_register(struct snd_info_entry *entry)
840 {
841 struct snd_info_entry *p;
842 int err;
843
844 if (!entry->p) {
845 err = __snd_info_register(entry);
846 if (err < 0)
847 return err;
848 }
849
850 list_for_each_entry(p, &entry->children, list) {
851 err = snd_info_register(p);
852 if (err < 0)
853 return err;
854 }
855
856 return 0;
857 }
858 EXPORT_SYMBOL(snd_info_register);
859
860 /**
861 * snd_card_rw_proc_new - Create a read/write text proc file entry for the card
862 * @card: the card instance
863 * @name: the file name
864 * @private_data: the arbitrary private data
865 * @read: the read callback
866 * @write: the write callback, NULL for read-only
867 *
868 * This proc file entry will be registered via snd_card_register() call, and
869 * it will be removed automatically at the card removal, too.
870 */
871 int snd_card_rw_proc_new(struct snd_card *card, const char *name,
872 void *private_data,
873 void (*read)(struct snd_info_entry *,
874 struct snd_info_buffer *),
875 void (*write)(struct snd_info_entry *entry,
876 struct snd_info_buffer *buffer))
877 {
878 struct snd_info_entry *entry;
879
880 entry = snd_info_create_card_entry(card, name, card->proc_root);
881 if (!entry)
882 return -ENOMEM;
883 snd_info_set_text_ops(entry, private_data, read);
884 if (write) {
885 entry->mode |= 0200;
886 entry->c.text.write = write;
887 }
888 return 0;
889 }
890 EXPORT_SYMBOL_GPL(snd_card_rw_proc_new);
891
892 /*
893
894 */
895
896 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
897 {
898 snd_iprintf(buffer,
899 "Advanced Linux Sound Architecture Driver Version k%s.\n",
900 init_utsname()->release);
901 }
902
903 static int __init snd_info_version_init(void)
904 {
905 struct snd_info_entry *entry;
906
907 entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
908 if (entry == NULL)
909 return -ENOMEM;
910 entry->c.text.read = snd_info_version_read;
911 return snd_info_register(entry); /* freed in error path */
912 }
Linux with added FPC-III support