xref: /linux/sound/core/memalloc.c (revision d67b569f5f620c0fb95d5212642746b7ba9d29e4)
1 /*
2  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
3  *                   Takashi Iwai <tiwai@suse.de>
4  *
5  *  Generic memory allocators
6  *
7  *
8  *   This program is free software; you can redistribute it and/or modify
9  *   it under the terms of the GNU General Public License as published by
10  *   the Free Software Foundation; either version 2 of the License, or
11  *   (at your option) any later version.
12  *
13  *   This program is distributed in the hope that it will be useful,
14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *   GNU General Public License for more details.
17  *
18  *   You should have received a copy of the GNU General Public License
19  *   along with this program; if not, write to the Free Software
20  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
21  *
22  */
23 
24 #include <linux/config.h>
25 #include <linux/module.h>
26 #include <linux/proc_fs.h>
27 #include <linux/init.h>
28 #include <linux/pci.h>
29 #include <linux/slab.h>
30 #include <linux/mm.h>
31 #include <asm/uaccess.h>
32 #include <linux/dma-mapping.h>
33 #include <linux/moduleparam.h>
34 #include <asm/semaphore.h>
35 #include <sound/memalloc.h>
36 #ifdef CONFIG_SBUS
37 #include <asm/sbus.h>
38 #endif
39 
40 
41 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@suse.cz>");
42 MODULE_DESCRIPTION("Memory allocator for ALSA system.");
43 MODULE_LICENSE("GPL");
44 
45 
46 #ifndef SNDRV_CARDS
47 #define SNDRV_CARDS	8
48 #endif
49 
50 /*
51  */
52 
53 void *snd_malloc_sgbuf_pages(struct device *device,
54                              size_t size, struct snd_dma_buffer *dmab,
55 			     size_t *res_size);
56 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);
57 
58 /*
59  */
60 
61 static DECLARE_MUTEX(list_mutex);
62 static LIST_HEAD(mem_list_head);
63 
64 /* buffer preservation list */
65 struct snd_mem_list {
66 	struct snd_dma_buffer buffer;
67 	unsigned int id;
68 	struct list_head list;
69 };
70 
71 /* id for pre-allocated buffers */
72 #define SNDRV_DMA_DEVICE_UNUSED (unsigned int)-1
73 
74 #ifdef CONFIG_SND_DEBUG
75 #define __ASTRING__(x) #x
76 #define snd_assert(expr, args...) do {\
77 	if (!(expr)) {\
78 		printk(KERN_ERR "snd-malloc: BUG? (%s) (called from %p)\n", __ASTRING__(expr), __builtin_return_address(0));\
79 		args;\
80 	}\
81 } while (0)
82 #else
83 #define snd_assert(expr, args...) /**/
84 #endif
85 
86 /*
87  *  Hacks
88  */
89 
90 #if defined(__i386__) || defined(__ppc__) || defined(__x86_64__)
91 /*
92  * A hack to allocate large buffers via dma_alloc_coherent()
93  *
94  * since dma_alloc_coherent always tries GFP_DMA when the requested
95  * pci memory region is below 32bit, it happens quite often that even
96  * 2 order of pages cannot be allocated.
97  *
98  * so in the following, we allocate at first without dma_mask, so that
99  * allocation will be done without GFP_DMA.  if the area doesn't match
100  * with the requested region, then realloate with the original dma_mask
101  * again.
102  *
103  * Really, we want to move this type of thing into dma_alloc_coherent()
104  * so dma_mask doesn't have to be messed with.
105  */
106 
107 static void *snd_dma_hack_alloc_coherent(struct device *dev, size_t size,
108 					 dma_addr_t *dma_handle, int flags)
109 {
110 	void *ret;
111 	u64 dma_mask, coherent_dma_mask;
112 
113 	if (dev == NULL || !dev->dma_mask)
114 		return dma_alloc_coherent(dev, size, dma_handle, flags);
115 	dma_mask = *dev->dma_mask;
116 	coherent_dma_mask = dev->coherent_dma_mask;
117 	*dev->dma_mask = 0xffffffff; 	/* do without masking */
118 	dev->coherent_dma_mask = 0xffffffff; 	/* do without masking */
119 	ret = dma_alloc_coherent(dev, size, dma_handle, flags);
120 	*dev->dma_mask = dma_mask;	/* restore */
121 	dev->coherent_dma_mask = coherent_dma_mask;	/* restore */
122 	if (ret) {
123 		/* obtained address is out of range? */
124 		if (((unsigned long)*dma_handle + size - 1) & ~dma_mask) {
125 			/* reallocate with the proper mask */
126 			dma_free_coherent(dev, size, ret, *dma_handle);
127 			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
128 		}
129 	} else {
130 		/* wish to success now with the proper mask... */
131 		if (dma_mask != 0xffffffffUL) {
132 			/* allocation with GFP_ATOMIC to avoid the long stall */
133 			flags &= ~GFP_KERNEL;
134 			flags |= GFP_ATOMIC;
135 			ret = dma_alloc_coherent(dev, size, dma_handle, flags);
136 		}
137 	}
138 	return ret;
139 }
140 
141 /* redefine dma_alloc_coherent for some architectures */
142 #undef dma_alloc_coherent
143 #define dma_alloc_coherent snd_dma_hack_alloc_coherent
144 
145 #endif /* arch */
146 
147 #if ! defined(__arm__)
148 #define NEED_RESERVE_PAGES
149 #endif
150 
151 /*
152  *
153  *  Generic memory allocators
154  *
155  */
156 
157 static long snd_allocated_pages; /* holding the number of allocated pages */
158 
159 static inline void inc_snd_pages(int order)
160 {
161 	snd_allocated_pages += 1 << order;
162 }
163 
164 static inline void dec_snd_pages(int order)
165 {
166 	snd_allocated_pages -= 1 << order;
167 }
168 
169 static void mark_pages(struct page *page, int order)
170 {
171 	struct page *last_page = page + (1 << order);
172 	while (page < last_page)
173 		SetPageReserved(page++);
174 }
175 
176 static void unmark_pages(struct page *page, int order)
177 {
178 	struct page *last_page = page + (1 << order);
179 	while (page < last_page)
180 		ClearPageReserved(page++);
181 }
182 
183 /**
184  * snd_malloc_pages - allocate pages with the given size
185  * @size: the size to allocate in bytes
186  * @gfp_flags: the allocation conditions, GFP_XXX
187  *
188  * Allocates the physically contiguous pages with the given size.
189  *
190  * Returns the pointer of the buffer, or NULL if no enoguh memory.
191  */
192 void *snd_malloc_pages(size_t size, unsigned int gfp_flags)
193 {
194 	int pg;
195 	void *res;
196 
197 	snd_assert(size > 0, return NULL);
198 	snd_assert(gfp_flags != 0, return NULL);
199 	pg = get_order(size);
200 	if ((res = (void *) __get_free_pages(gfp_flags, pg)) != NULL) {
201 		mark_pages(virt_to_page(res), pg);
202 		inc_snd_pages(pg);
203 	}
204 	return res;
205 }
206 
207 /**
208  * snd_free_pages - release the pages
209  * @ptr: the buffer pointer to release
210  * @size: the allocated buffer size
211  *
212  * Releases the buffer allocated via snd_malloc_pages().
213  */
214 void snd_free_pages(void *ptr, size_t size)
215 {
216 	int pg;
217 
218 	if (ptr == NULL)
219 		return;
220 	pg = get_order(size);
221 	dec_snd_pages(pg);
222 	unmark_pages(virt_to_page(ptr), pg);
223 	free_pages((unsigned long) ptr, pg);
224 }
225 
226 /*
227  *
228  *  Bus-specific memory allocators
229  *
230  */
231 
232 /* allocate the coherent DMA pages */
233 static void *snd_malloc_dev_pages(struct device *dev, size_t size, dma_addr_t *dma)
234 {
235 	int pg;
236 	void *res;
237 	unsigned int gfp_flags;
238 
239 	snd_assert(size > 0, return NULL);
240 	snd_assert(dma != NULL, return NULL);
241 	pg = get_order(size);
242 	gfp_flags = GFP_KERNEL
243 		| __GFP_NORETRY /* don't trigger OOM-killer */
244 		| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
245 	res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);
246 	if (res != NULL) {
247 #ifdef NEED_RESERVE_PAGES
248 		mark_pages(virt_to_page(res), pg); /* should be dma_to_page() */
249 #endif
250 		inc_snd_pages(pg);
251 	}
252 
253 	return res;
254 }
255 
256 /* free the coherent DMA pages */
257 static void snd_free_dev_pages(struct device *dev, size_t size, void *ptr,
258 			       dma_addr_t dma)
259 {
260 	int pg;
261 
262 	if (ptr == NULL)
263 		return;
264 	pg = get_order(size);
265 	dec_snd_pages(pg);
266 #ifdef NEED_RESERVE_PAGES
267 	unmark_pages(virt_to_page(ptr), pg); /* should be dma_to_page() */
268 #endif
269 	dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);
270 }
271 
272 #ifdef CONFIG_SBUS
273 
274 static void *snd_malloc_sbus_pages(struct device *dev, size_t size,
275 				   dma_addr_t *dma_addr)
276 {
277 	struct sbus_dev *sdev = (struct sbus_dev *)dev;
278 	int pg;
279 	void *res;
280 
281 	snd_assert(size > 0, return NULL);
282 	snd_assert(dma_addr != NULL, return NULL);
283 	pg = get_order(size);
284 	res = sbus_alloc_consistent(sdev, PAGE_SIZE * (1 << pg), dma_addr);
285 	if (res != NULL)
286 		inc_snd_pages(pg);
287 	return res;
288 }
289 
290 static void snd_free_sbus_pages(struct device *dev, size_t size,
291 				void *ptr, dma_addr_t dma_addr)
292 {
293 	struct sbus_dev *sdev = (struct sbus_dev *)dev;
294 	int pg;
295 
296 	if (ptr == NULL)
297 		return;
298 	pg = get_order(size);
299 	dec_snd_pages(pg);
300 	sbus_free_consistent(sdev, PAGE_SIZE * (1 << pg), ptr, dma_addr);
301 }
302 
303 #endif /* CONFIG_SBUS */
304 
305 /*
306  *
307  *  ALSA generic memory management
308  *
309  */
310 
311 
312 /**
313  * snd_dma_alloc_pages - allocate the buffer area according to the given type
314  * @type: the DMA buffer type
315  * @device: the device pointer
316  * @size: the buffer size to allocate
317  * @dmab: buffer allocation record to store the allocated data
318  *
319  * Calls the memory-allocator function for the corresponding
320  * buffer type.
321  *
322  * Returns zero if the buffer with the given size is allocated successfuly,
323  * other a negative value at error.
324  */
325 int snd_dma_alloc_pages(int type, struct device *device, size_t size,
326 			struct snd_dma_buffer *dmab)
327 {
328 	snd_assert(size > 0, return -ENXIO);
329 	snd_assert(dmab != NULL, return -ENXIO);
330 
331 	dmab->dev.type = type;
332 	dmab->dev.dev = device;
333 	dmab->bytes = 0;
334 	switch (type) {
335 	case SNDRV_DMA_TYPE_CONTINUOUS:
336 		dmab->area = snd_malloc_pages(size, (unsigned long)device);
337 		dmab->addr = 0;
338 		break;
339 #ifdef CONFIG_SBUS
340 	case SNDRV_DMA_TYPE_SBUS:
341 		dmab->area = snd_malloc_sbus_pages(device, size, &dmab->addr);
342 		break;
343 #endif
344 	case SNDRV_DMA_TYPE_DEV:
345 		dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);
346 		break;
347 	case SNDRV_DMA_TYPE_DEV_SG:
348 		snd_malloc_sgbuf_pages(device, size, dmab, NULL);
349 		break;
350 	default:
351 		printk(KERN_ERR "snd-malloc: invalid device type %d\n", type);
352 		dmab->area = NULL;
353 		dmab->addr = 0;
354 		return -ENXIO;
355 	}
356 	if (! dmab->area)
357 		return -ENOMEM;
358 	dmab->bytes = size;
359 	return 0;
360 }
361 
362 /**
363  * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
364  * @type: the DMA buffer type
365  * @device: the device pointer
366  * @size: the buffer size to allocate
367  * @dmab: buffer allocation record to store the allocated data
368  *
369  * Calls the memory-allocator function for the corresponding
370  * buffer type.  When no space is left, this function reduces the size and
371  * tries to allocate again.  The size actually allocated is stored in
372  * res_size argument.
373  *
374  * Returns zero if the buffer with the given size is allocated successfuly,
375  * other a negative value at error.
376  */
377 int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
378 				 struct snd_dma_buffer *dmab)
379 {
380 	int err;
381 
382 	snd_assert(size > 0, return -ENXIO);
383 	snd_assert(dmab != NULL, return -ENXIO);
384 
385 	while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
386 		if (err != -ENOMEM)
387 			return err;
388 		size >>= 1;
389 		if (size <= PAGE_SIZE)
390 			return -ENOMEM;
391 	}
392 	if (! dmab->area)
393 		return -ENOMEM;
394 	return 0;
395 }
396 
397 
398 /**
399  * snd_dma_free_pages - release the allocated buffer
400  * @dmab: the buffer allocation record to release
401  *
402  * Releases the allocated buffer via snd_dma_alloc_pages().
403  */
404 void snd_dma_free_pages(struct snd_dma_buffer *dmab)
405 {
406 	switch (dmab->dev.type) {
407 	case SNDRV_DMA_TYPE_CONTINUOUS:
408 		snd_free_pages(dmab->area, dmab->bytes);
409 		break;
410 #ifdef CONFIG_SBUS
411 	case SNDRV_DMA_TYPE_SBUS:
412 		snd_free_sbus_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
413 		break;
414 #endif
415 	case SNDRV_DMA_TYPE_DEV:
416 		snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
417 		break;
418 	case SNDRV_DMA_TYPE_DEV_SG:
419 		snd_free_sgbuf_pages(dmab);
420 		break;
421 	default:
422 		printk(KERN_ERR "snd-malloc: invalid device type %d\n", dmab->dev.type);
423 	}
424 }
425 
426 
427 /**
428  * snd_dma_get_reserved - get the reserved buffer for the given device
429  * @dmab: the buffer allocation record to store
430  * @id: the buffer id
431  *
432  * Looks for the reserved-buffer list and re-uses if the same buffer
433  * is found in the list.  When the buffer is found, it's removed from the free list.
434  *
435  * Returns the size of buffer if the buffer is found, or zero if not found.
436  */
437 size_t snd_dma_get_reserved_buf(struct snd_dma_buffer *dmab, unsigned int id)
438 {
439 	struct list_head *p;
440 	struct snd_mem_list *mem;
441 
442 	snd_assert(dmab, return 0);
443 
444 	down(&list_mutex);
445 	list_for_each(p, &mem_list_head) {
446 		mem = list_entry(p, struct snd_mem_list, list);
447 		if (mem->id == id &&
448 		    (mem->buffer.dev.dev == NULL || dmab->dev.dev == NULL ||
449 		     ! memcmp(&mem->buffer.dev, &dmab->dev, sizeof(dmab->dev)))) {
450 			struct device *dev = dmab->dev.dev;
451 			list_del(p);
452 			*dmab = mem->buffer;
453 			if (dmab->dev.dev == NULL)
454 				dmab->dev.dev = dev;
455 			kfree(mem);
456 			up(&list_mutex);
457 			return dmab->bytes;
458 		}
459 	}
460 	up(&list_mutex);
461 	return 0;
462 }
463 
464 /**
465  * snd_dma_reserve_buf - reserve the buffer
466  * @dmab: the buffer to reserve
467  * @id: the buffer id
468  *
469  * Reserves the given buffer as a reserved buffer.
470  *
471  * Returns zero if successful, or a negative code at error.
472  */
473 int snd_dma_reserve_buf(struct snd_dma_buffer *dmab, unsigned int id)
474 {
475 	struct snd_mem_list *mem;
476 
477 	snd_assert(dmab, return -EINVAL);
478 	mem = kmalloc(sizeof(*mem), GFP_KERNEL);
479 	if (! mem)
480 		return -ENOMEM;
481 	down(&list_mutex);
482 	mem->buffer = *dmab;
483 	mem->id = id;
484 	list_add_tail(&mem->list, &mem_list_head);
485 	up(&list_mutex);
486 	return 0;
487 }
488 
489 /*
490  * purge all reserved buffers
491  */
492 static void free_all_reserved_pages(void)
493 {
494 	struct list_head *p;
495 	struct snd_mem_list *mem;
496 
497 	down(&list_mutex);
498 	while (! list_empty(&mem_list_head)) {
499 		p = mem_list_head.next;
500 		mem = list_entry(p, struct snd_mem_list, list);
501 		list_del(p);
502 		snd_dma_free_pages(&mem->buffer);
503 		kfree(mem);
504 	}
505 	up(&list_mutex);
506 }
507 
508 
509 #ifdef CONFIG_PROC_FS
510 /*
511  * proc file interface
512  */
513 #define SND_MEM_PROC_FILE	"driver/snd-page-alloc"
514 struct proc_dir_entry *snd_mem_proc;
515 
516 static int snd_mem_proc_read(char *page, char **start, off_t off,
517 			     int count, int *eof, void *data)
518 {
519 	int len = 0;
520 	long pages = snd_allocated_pages >> (PAGE_SHIFT-12);
521 	struct list_head *p;
522 	struct snd_mem_list *mem;
523 	int devno;
524 	static char *types[] = { "UNKNOWN", "CONT", "DEV", "DEV-SG", "SBUS" };
525 
526 	down(&list_mutex);
527 	len += snprintf(page + len, count - len,
528 			"pages  : %li bytes (%li pages per %likB)\n",
529 			pages * PAGE_SIZE, pages, PAGE_SIZE / 1024);
530 	devno = 0;
531 	list_for_each(p, &mem_list_head) {
532 		mem = list_entry(p, struct snd_mem_list, list);
533 		devno++;
534 		len += snprintf(page + len, count - len,
535 				"buffer %d : ID %08x : type %s\n",
536 				devno, mem->id, types[mem->buffer.dev.type]);
537 		len += snprintf(page + len, count - len,
538 				"  addr = 0x%lx, size = %d bytes\n",
539 				(unsigned long)mem->buffer.addr, (int)mem->buffer.bytes);
540 	}
541 	up(&list_mutex);
542 	return len;
543 }
544 
545 /* FIXME: for pci only - other bus? */
546 #ifdef CONFIG_PCI
547 #define gettoken(bufp) strsep(bufp, " \t\n")
548 
549 static int snd_mem_proc_write(struct file *file, const char __user *buffer,
550 			      unsigned long count, void *data)
551 {
552 	char buf[128];
553 	char *token, *p;
554 
555 	if (count > ARRAY_SIZE(buf) - 1)
556 		count = ARRAY_SIZE(buf) - 1;
557 	if (copy_from_user(buf, buffer, count))
558 		return -EFAULT;
559 	buf[ARRAY_SIZE(buf) - 1] = '\0';
560 
561 	p = buf;
562 	token = gettoken(&p);
563 	if (! token || *token == '#')
564 		return (int)count;
565 	if (strcmp(token, "add") == 0) {
566 		char *endp;
567 		int vendor, device, size, buffers;
568 		long mask;
569 		int i, alloced;
570 		struct pci_dev *pci;
571 
572 		if ((token = gettoken(&p)) == NULL ||
573 		    (vendor = simple_strtol(token, NULL, 0)) <= 0 ||
574 		    (token = gettoken(&p)) == NULL ||
575 		    (device = simple_strtol(token, NULL, 0)) <= 0 ||
576 		    (token = gettoken(&p)) == NULL ||
577 		    (mask = simple_strtol(token, NULL, 0)) < 0 ||
578 		    (token = gettoken(&p)) == NULL ||
579 		    (size = memparse(token, &endp)) < 64*1024 ||
580 		    size > 16*1024*1024 /* too big */ ||
581 		    (token = gettoken(&p)) == NULL ||
582 		    (buffers = simple_strtol(token, NULL, 0)) <= 0 ||
583 		    buffers > 4) {
584 			printk(KERN_ERR "snd-page-alloc: invalid proc write format\n");
585 			return (int)count;
586 		}
587 		vendor &= 0xffff;
588 		device &= 0xffff;
589 
590 		alloced = 0;
591 		pci = NULL;
592 		while ((pci = pci_find_device(vendor, device, pci)) != NULL) {
593 			if (mask > 0 && mask < 0xffffffff) {
594 				if (pci_set_dma_mask(pci, mask) < 0 ||
595 				    pci_set_consistent_dma_mask(pci, mask) < 0) {
596 					printk(KERN_ERR "snd-page-alloc: cannot set DMA mask %lx for pci %04x:%04x\n", mask, vendor, device);
597 					return (int)count;
598 				}
599 			}
600 			for (i = 0; i < buffers; i++) {
601 				struct snd_dma_buffer dmab;
602 				memset(&dmab, 0, sizeof(dmab));
603 				if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(pci),
604 							size, &dmab) < 0) {
605 					printk(KERN_ERR "snd-page-alloc: cannot allocate buffer pages (size = %d)\n", size);
606 					return (int)count;
607 				}
608 				snd_dma_reserve_buf(&dmab, snd_dma_pci_buf_id(pci));
609 			}
610 			alloced++;
611 		}
612 		if (! alloced) {
613 			for (i = 0; i < buffers; i++) {
614 				struct snd_dma_buffer dmab;
615 				memset(&dmab, 0, sizeof(dmab));
616 				/* FIXME: We can allocate only in ZONE_DMA
617 				 * without a device pointer!
618 				 */
619 				if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, NULL,
620 							size, &dmab) < 0) {
621 					printk(KERN_ERR "snd-page-alloc: cannot allocate buffer pages (size = %d)\n", size);
622 					break;
623 				}
624 				snd_dma_reserve_buf(&dmab, (unsigned int)((vendor << 16) | device));
625 			}
626 		}
627 	} else if (strcmp(token, "erase") == 0)
628 		/* FIXME: need for releasing each buffer chunk? */
629 		free_all_reserved_pages();
630 	else
631 		printk(KERN_ERR "snd-page-alloc: invalid proc cmd\n");
632 	return (int)count;
633 }
634 #endif /* CONFIG_PCI */
635 #endif /* CONFIG_PROC_FS */
636 
637 /*
638  * module entry
639  */
640 
641 static int __init snd_mem_init(void)
642 {
643 #ifdef CONFIG_PROC_FS
644 	snd_mem_proc = create_proc_entry(SND_MEM_PROC_FILE, 0644, NULL);
645 	if (snd_mem_proc) {
646 		snd_mem_proc->read_proc = snd_mem_proc_read;
647 #ifdef CONFIG_PCI
648 		snd_mem_proc->write_proc = snd_mem_proc_write;
649 #endif
650 	}
651 #endif
652 	return 0;
653 }
654 
655 static void __exit snd_mem_exit(void)
656 {
657 	if (snd_mem_proc)
658 		remove_proc_entry(SND_MEM_PROC_FILE, NULL);
659 	free_all_reserved_pages();
660 	if (snd_allocated_pages > 0)
661 		printk(KERN_ERR "snd-malloc: Memory leak?  pages not freed = %li\n", snd_allocated_pages);
662 }
663 
664 
665 module_init(snd_mem_init)
666 module_exit(snd_mem_exit)
667 
668 
669 /*
670  * exports
671  */
672 EXPORT_SYMBOL(snd_dma_alloc_pages);
673 EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
674 EXPORT_SYMBOL(snd_dma_free_pages);
675 
676 EXPORT_SYMBOL(snd_dma_get_reserved_buf);
677 EXPORT_SYMBOL(snd_dma_reserve_buf);
678 
679 EXPORT_SYMBOL(snd_malloc_pages);
680 EXPORT_SYMBOL(snd_free_pages);
681