xref: /linux/sound/core/memalloc.c (revision 0e685c3e7158d35626d6d76b9f859eae806d87fa)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *                   Takashi Iwai <tiwai@suse.de>
5  *
6  *  Generic memory allocators
7  */
8 
9 #include <linux/slab.h>
10 #include <linux/mm.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/dma-map-ops.h>
13 #include <linux/genalloc.h>
14 #include <linux/highmem.h>
15 #include <linux/vmalloc.h>
16 #ifdef CONFIG_X86
17 #include <asm/set_memory.h>
18 #endif
19 #include <sound/memalloc.h>
20 #include "memalloc_local.h"
21 
22 #define DEFAULT_GFP \
23 	(GFP_KERNEL | \
24 	 __GFP_RETRY_MAYFAIL | /* don't trigger OOM-killer */ \
25 	 __GFP_NOWARN)   /* no stack trace print - this call is non-critical */
26 
27 static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab);
28 
29 #ifdef CONFIG_SND_DMA_SGBUF
30 static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size);
31 #endif
32 
33 static void *__snd_dma_alloc_pages(struct snd_dma_buffer *dmab, size_t size)
34 {
35 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
36 
37 	if (WARN_ON_ONCE(!ops || !ops->alloc))
38 		return NULL;
39 	return ops->alloc(dmab, size);
40 }
41 
42 /**
43  * snd_dma_alloc_dir_pages - allocate the buffer area according to the given
44  *	type and direction
45  * @type: the DMA buffer type
46  * @device: the device pointer
47  * @dir: DMA direction
48  * @size: the buffer size to allocate
49  * @dmab: buffer allocation record to store the allocated data
50  *
51  * Calls the memory-allocator function for the corresponding
52  * buffer type.
53  *
54  * Return: Zero if the buffer with the given size is allocated successfully,
55  * otherwise a negative value on error.
56  */
57 int snd_dma_alloc_dir_pages(int type, struct device *device,
58 			    enum dma_data_direction dir, size_t size,
59 			    struct snd_dma_buffer *dmab)
60 {
61 	if (WARN_ON(!size))
62 		return -ENXIO;
63 	if (WARN_ON(!dmab))
64 		return -ENXIO;
65 
66 	size = PAGE_ALIGN(size);
67 	dmab->dev.type = type;
68 	dmab->dev.dev = device;
69 	dmab->dev.dir = dir;
70 	dmab->bytes = 0;
71 	dmab->addr = 0;
72 	dmab->private_data = NULL;
73 	dmab->area = __snd_dma_alloc_pages(dmab, size);
74 	if (!dmab->area)
75 		return -ENOMEM;
76 	dmab->bytes = size;
77 	return 0;
78 }
79 EXPORT_SYMBOL(snd_dma_alloc_dir_pages);
80 
81 /**
82  * snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
83  * @type: the DMA buffer type
84  * @device: the device pointer
85  * @size: the buffer size to allocate
86  * @dmab: buffer allocation record to store the allocated data
87  *
88  * Calls the memory-allocator function for the corresponding
89  * buffer type.  When no space is left, this function reduces the size and
90  * tries to allocate again.  The size actually allocated is stored in
91  * res_size argument.
92  *
93  * Return: Zero if the buffer with the given size is allocated successfully,
94  * otherwise a negative value on error.
95  */
96 int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
97 				 struct snd_dma_buffer *dmab)
98 {
99 	int err;
100 
101 	while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
102 		if (err != -ENOMEM)
103 			return err;
104 		if (size <= PAGE_SIZE)
105 			return -ENOMEM;
106 		size >>= 1;
107 		size = PAGE_SIZE << get_order(size);
108 	}
109 	if (! dmab->area)
110 		return -ENOMEM;
111 	return 0;
112 }
113 EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
114 
115 /**
116  * snd_dma_free_pages - release the allocated buffer
117  * @dmab: the buffer allocation record to release
118  *
119  * Releases the allocated buffer via snd_dma_alloc_pages().
120  */
121 void snd_dma_free_pages(struct snd_dma_buffer *dmab)
122 {
123 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
124 
125 	if (ops && ops->free)
126 		ops->free(dmab);
127 }
128 EXPORT_SYMBOL(snd_dma_free_pages);
129 
130 /* called by devres */
131 static void __snd_release_pages(struct device *dev, void *res)
132 {
133 	snd_dma_free_pages(res);
134 }
135 
136 /**
137  * snd_devm_alloc_dir_pages - allocate the buffer and manage with devres
138  * @dev: the device pointer
139  * @type: the DMA buffer type
140  * @dir: DMA direction
141  * @size: the buffer size to allocate
142  *
143  * Allocate buffer pages depending on the given type and manage using devres.
144  * The pages will be released automatically at the device removal.
145  *
146  * Unlike snd_dma_alloc_pages(), this function requires the real device pointer,
147  * hence it can't work with SNDRV_DMA_TYPE_CONTINUOUS or
148  * SNDRV_DMA_TYPE_VMALLOC type.
149  *
150  * Return: the snd_dma_buffer object at success, or NULL if failed
151  */
152 struct snd_dma_buffer *
153 snd_devm_alloc_dir_pages(struct device *dev, int type,
154 			 enum dma_data_direction dir, size_t size)
155 {
156 	struct snd_dma_buffer *dmab;
157 	int err;
158 
159 	if (WARN_ON(type == SNDRV_DMA_TYPE_CONTINUOUS ||
160 		    type == SNDRV_DMA_TYPE_VMALLOC))
161 		return NULL;
162 
163 	dmab = devres_alloc(__snd_release_pages, sizeof(*dmab), GFP_KERNEL);
164 	if (!dmab)
165 		return NULL;
166 
167 	err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
168 	if (err < 0) {
169 		devres_free(dmab);
170 		return NULL;
171 	}
172 
173 	devres_add(dev, dmab);
174 	return dmab;
175 }
176 EXPORT_SYMBOL_GPL(snd_devm_alloc_dir_pages);
177 
178 /**
179  * snd_dma_buffer_mmap - perform mmap of the given DMA buffer
180  * @dmab: buffer allocation information
181  * @area: VM area information
182  *
183  * Return: zero if successful, or a negative error code
184  */
185 int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab,
186 			struct vm_area_struct *area)
187 {
188 	const struct snd_malloc_ops *ops;
189 
190 	if (!dmab)
191 		return -ENOENT;
192 	ops = snd_dma_get_ops(dmab);
193 	if (ops && ops->mmap)
194 		return ops->mmap(dmab, area);
195 	else
196 		return -ENOENT;
197 }
198 EXPORT_SYMBOL(snd_dma_buffer_mmap);
199 
200 #ifdef CONFIG_HAS_DMA
201 /**
202  * snd_dma_buffer_sync - sync DMA buffer between CPU and device
203  * @dmab: buffer allocation information
204  * @mode: sync mode
205  */
206 void snd_dma_buffer_sync(struct snd_dma_buffer *dmab,
207 			 enum snd_dma_sync_mode mode)
208 {
209 	const struct snd_malloc_ops *ops;
210 
211 	if (!dmab || !dmab->dev.need_sync)
212 		return;
213 	ops = snd_dma_get_ops(dmab);
214 	if (ops && ops->sync)
215 		ops->sync(dmab, mode);
216 }
217 EXPORT_SYMBOL_GPL(snd_dma_buffer_sync);
218 #endif /* CONFIG_HAS_DMA */
219 
220 /**
221  * snd_sgbuf_get_addr - return the physical address at the corresponding offset
222  * @dmab: buffer allocation information
223  * @offset: offset in the ring buffer
224  *
225  * Return: the physical address
226  */
227 dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset)
228 {
229 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
230 
231 	if (ops && ops->get_addr)
232 		return ops->get_addr(dmab, offset);
233 	else
234 		return dmab->addr + offset;
235 }
236 EXPORT_SYMBOL(snd_sgbuf_get_addr);
237 
238 /**
239  * snd_sgbuf_get_page - return the physical page at the corresponding offset
240  * @dmab: buffer allocation information
241  * @offset: offset in the ring buffer
242  *
243  * Return: the page pointer
244  */
245 struct page *snd_sgbuf_get_page(struct snd_dma_buffer *dmab, size_t offset)
246 {
247 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
248 
249 	if (ops && ops->get_page)
250 		return ops->get_page(dmab, offset);
251 	else
252 		return virt_to_page(dmab->area + offset);
253 }
254 EXPORT_SYMBOL(snd_sgbuf_get_page);
255 
256 /**
257  * snd_sgbuf_get_chunk_size - compute the max chunk size with continuous pages
258  *	on sg-buffer
259  * @dmab: buffer allocation information
260  * @ofs: offset in the ring buffer
261  * @size: the requested size
262  *
263  * Return: the chunk size
264  */
265 unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
266 				      unsigned int ofs, unsigned int size)
267 {
268 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
269 
270 	if (ops && ops->get_chunk_size)
271 		return ops->get_chunk_size(dmab, ofs, size);
272 	else
273 		return size;
274 }
275 EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
276 
277 /*
278  * Continuous pages allocator
279  */
280 static void *do_alloc_pages(struct device *dev, size_t size, dma_addr_t *addr,
281 			    bool wc)
282 {
283 	void *p;
284 	gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
285 
286  again:
287 	p = alloc_pages_exact(size, gfp);
288 	if (!p)
289 		return NULL;
290 	*addr = page_to_phys(virt_to_page(p));
291 	if (!dev)
292 		return p;
293 	if ((*addr + size - 1) & ~dev->coherent_dma_mask) {
294 		if (IS_ENABLED(CONFIG_ZONE_DMA32) && !(gfp & GFP_DMA32)) {
295 			gfp |= GFP_DMA32;
296 			goto again;
297 		}
298 		if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
299 			gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
300 			goto again;
301 		}
302 	}
303 #ifdef CONFIG_X86
304 	if (wc)
305 		set_memory_wc((unsigned long)(p), size >> PAGE_SHIFT);
306 #endif
307 	return p;
308 }
309 
310 static void do_free_pages(void *p, size_t size, bool wc)
311 {
312 #ifdef CONFIG_X86
313 	if (wc)
314 		set_memory_wb((unsigned long)(p), size >> PAGE_SHIFT);
315 #endif
316 	free_pages_exact(p, size);
317 }
318 
319 
320 static void *snd_dma_continuous_alloc(struct snd_dma_buffer *dmab, size_t size)
321 {
322 	return do_alloc_pages(dmab->dev.dev, size, &dmab->addr, false);
323 }
324 
325 static void snd_dma_continuous_free(struct snd_dma_buffer *dmab)
326 {
327 	do_free_pages(dmab->area, dmab->bytes, false);
328 }
329 
330 static int snd_dma_continuous_mmap(struct snd_dma_buffer *dmab,
331 				   struct vm_area_struct *area)
332 {
333 	return remap_pfn_range(area, area->vm_start,
334 			       dmab->addr >> PAGE_SHIFT,
335 			       area->vm_end - area->vm_start,
336 			       area->vm_page_prot);
337 }
338 
339 static const struct snd_malloc_ops snd_dma_continuous_ops = {
340 	.alloc = snd_dma_continuous_alloc,
341 	.free = snd_dma_continuous_free,
342 	.mmap = snd_dma_continuous_mmap,
343 };
344 
345 /*
346  * VMALLOC allocator
347  */
348 static void *snd_dma_vmalloc_alloc(struct snd_dma_buffer *dmab, size_t size)
349 {
350 	return vmalloc(size);
351 }
352 
353 static void snd_dma_vmalloc_free(struct snd_dma_buffer *dmab)
354 {
355 	vfree(dmab->area);
356 }
357 
358 static int snd_dma_vmalloc_mmap(struct snd_dma_buffer *dmab,
359 				struct vm_area_struct *area)
360 {
361 	return remap_vmalloc_range(area, dmab->area, 0);
362 }
363 
364 #define get_vmalloc_page_addr(dmab, offset) \
365 	page_to_phys(vmalloc_to_page((dmab)->area + (offset)))
366 
367 static dma_addr_t snd_dma_vmalloc_get_addr(struct snd_dma_buffer *dmab,
368 					   size_t offset)
369 {
370 	return get_vmalloc_page_addr(dmab, offset) + offset % PAGE_SIZE;
371 }
372 
373 static struct page *snd_dma_vmalloc_get_page(struct snd_dma_buffer *dmab,
374 					     size_t offset)
375 {
376 	return vmalloc_to_page(dmab->area + offset);
377 }
378 
379 static unsigned int
380 snd_dma_vmalloc_get_chunk_size(struct snd_dma_buffer *dmab,
381 			       unsigned int ofs, unsigned int size)
382 {
383 	unsigned int start, end;
384 	unsigned long addr;
385 
386 	start = ALIGN_DOWN(ofs, PAGE_SIZE);
387 	end = ofs + size - 1; /* the last byte address */
388 	/* check page continuity */
389 	addr = get_vmalloc_page_addr(dmab, start);
390 	for (;;) {
391 		start += PAGE_SIZE;
392 		if (start > end)
393 			break;
394 		addr += PAGE_SIZE;
395 		if (get_vmalloc_page_addr(dmab, start) != addr)
396 			return start - ofs;
397 	}
398 	/* ok, all on continuous pages */
399 	return size;
400 }
401 
402 static const struct snd_malloc_ops snd_dma_vmalloc_ops = {
403 	.alloc = snd_dma_vmalloc_alloc,
404 	.free = snd_dma_vmalloc_free,
405 	.mmap = snd_dma_vmalloc_mmap,
406 	.get_addr = snd_dma_vmalloc_get_addr,
407 	.get_page = snd_dma_vmalloc_get_page,
408 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
409 };
410 
411 #ifdef CONFIG_HAS_DMA
412 /*
413  * IRAM allocator
414  */
415 #ifdef CONFIG_GENERIC_ALLOCATOR
416 static void *snd_dma_iram_alloc(struct snd_dma_buffer *dmab, size_t size)
417 {
418 	struct device *dev = dmab->dev.dev;
419 	struct gen_pool *pool;
420 	void *p;
421 
422 	if (dev->of_node) {
423 		pool = of_gen_pool_get(dev->of_node, "iram", 0);
424 		/* Assign the pool into private_data field */
425 		dmab->private_data = pool;
426 
427 		p = gen_pool_dma_alloc_align(pool, size, &dmab->addr, PAGE_SIZE);
428 		if (p)
429 			return p;
430 	}
431 
432 	/* Internal memory might have limited size and no enough space,
433 	 * so if we fail to malloc, try to fetch memory traditionally.
434 	 */
435 	dmab->dev.type = SNDRV_DMA_TYPE_DEV;
436 	return __snd_dma_alloc_pages(dmab, size);
437 }
438 
439 static void snd_dma_iram_free(struct snd_dma_buffer *dmab)
440 {
441 	struct gen_pool *pool = dmab->private_data;
442 
443 	if (pool && dmab->area)
444 		gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
445 }
446 
447 static int snd_dma_iram_mmap(struct snd_dma_buffer *dmab,
448 			     struct vm_area_struct *area)
449 {
450 	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
451 	return remap_pfn_range(area, area->vm_start,
452 			       dmab->addr >> PAGE_SHIFT,
453 			       area->vm_end - area->vm_start,
454 			       area->vm_page_prot);
455 }
456 
457 static const struct snd_malloc_ops snd_dma_iram_ops = {
458 	.alloc = snd_dma_iram_alloc,
459 	.free = snd_dma_iram_free,
460 	.mmap = snd_dma_iram_mmap,
461 };
462 #endif /* CONFIG_GENERIC_ALLOCATOR */
463 
464 /*
465  * Coherent device pages allocator
466  */
467 static void *snd_dma_dev_alloc(struct snd_dma_buffer *dmab, size_t size)
468 {
469 	return dma_alloc_coherent(dmab->dev.dev, size, &dmab->addr, DEFAULT_GFP);
470 }
471 
472 static void snd_dma_dev_free(struct snd_dma_buffer *dmab)
473 {
474 	dma_free_coherent(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
475 }
476 
477 static int snd_dma_dev_mmap(struct snd_dma_buffer *dmab,
478 			    struct vm_area_struct *area)
479 {
480 	return dma_mmap_coherent(dmab->dev.dev, area,
481 				 dmab->area, dmab->addr, dmab->bytes);
482 }
483 
484 static const struct snd_malloc_ops snd_dma_dev_ops = {
485 	.alloc = snd_dma_dev_alloc,
486 	.free = snd_dma_dev_free,
487 	.mmap = snd_dma_dev_mmap,
488 };
489 
490 /*
491  * Write-combined pages
492  */
493 /* x86-specific allocations */
494 #ifdef CONFIG_SND_DMA_SGBUF
495 static void *snd_dma_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
496 {
497 	return do_alloc_pages(dmab->dev.dev, size, &dmab->addr, true);
498 }
499 
500 static void snd_dma_wc_free(struct snd_dma_buffer *dmab)
501 {
502 	do_free_pages(dmab->area, dmab->bytes, true);
503 }
504 
505 static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab,
506 			   struct vm_area_struct *area)
507 {
508 	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
509 	return snd_dma_continuous_mmap(dmab, area);
510 }
511 #else
512 static void *snd_dma_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
513 {
514 	return dma_alloc_wc(dmab->dev.dev, size, &dmab->addr, DEFAULT_GFP);
515 }
516 
517 static void snd_dma_wc_free(struct snd_dma_buffer *dmab)
518 {
519 	dma_free_wc(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
520 }
521 
522 static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab,
523 			   struct vm_area_struct *area)
524 {
525 	return dma_mmap_wc(dmab->dev.dev, area,
526 			   dmab->area, dmab->addr, dmab->bytes);
527 }
528 #endif /* CONFIG_SND_DMA_SGBUF */
529 
530 static const struct snd_malloc_ops snd_dma_wc_ops = {
531 	.alloc = snd_dma_wc_alloc,
532 	.free = snd_dma_wc_free,
533 	.mmap = snd_dma_wc_mmap,
534 };
535 
536 /*
537  * Non-contiguous pages allocator
538  */
539 static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
540 {
541 	struct sg_table *sgt;
542 	void *p;
543 
544 #ifdef CONFIG_SND_DMA_SGBUF
545 	if (cpu_feature_enabled(X86_FEATURE_XENPV))
546 		return snd_dma_sg_fallback_alloc(dmab, size);
547 #endif
548 	sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
549 				      DEFAULT_GFP, 0);
550 #ifdef CONFIG_SND_DMA_SGBUF
551 	if (!sgt && !get_dma_ops(dmab->dev.dev))
552 		return snd_dma_sg_fallback_alloc(dmab, size);
553 #endif
554 	if (!sgt)
555 		return NULL;
556 
557 	dmab->dev.need_sync = dma_need_sync(dmab->dev.dev,
558 					    sg_dma_address(sgt->sgl));
559 	p = dma_vmap_noncontiguous(dmab->dev.dev, size, sgt);
560 	if (p) {
561 		dmab->private_data = sgt;
562 		/* store the first page address for convenience */
563 		dmab->addr = snd_sgbuf_get_addr(dmab, 0);
564 	} else {
565 		dma_free_noncontiguous(dmab->dev.dev, size, sgt, dmab->dev.dir);
566 	}
567 	return p;
568 }
569 
570 static void snd_dma_noncontig_free(struct snd_dma_buffer *dmab)
571 {
572 	dma_vunmap_noncontiguous(dmab->dev.dev, dmab->area);
573 	dma_free_noncontiguous(dmab->dev.dev, dmab->bytes, dmab->private_data,
574 			       dmab->dev.dir);
575 }
576 
577 static int snd_dma_noncontig_mmap(struct snd_dma_buffer *dmab,
578 				  struct vm_area_struct *area)
579 {
580 	return dma_mmap_noncontiguous(dmab->dev.dev, area,
581 				      dmab->bytes, dmab->private_data);
582 }
583 
584 static void snd_dma_noncontig_sync(struct snd_dma_buffer *dmab,
585 				   enum snd_dma_sync_mode mode)
586 {
587 	if (mode == SNDRV_DMA_SYNC_CPU) {
588 		if (dmab->dev.dir == DMA_TO_DEVICE)
589 			return;
590 		invalidate_kernel_vmap_range(dmab->area, dmab->bytes);
591 		dma_sync_sgtable_for_cpu(dmab->dev.dev, dmab->private_data,
592 					 dmab->dev.dir);
593 	} else {
594 		if (dmab->dev.dir == DMA_FROM_DEVICE)
595 			return;
596 		flush_kernel_vmap_range(dmab->area, dmab->bytes);
597 		dma_sync_sgtable_for_device(dmab->dev.dev, dmab->private_data,
598 					    dmab->dev.dir);
599 	}
600 }
601 
602 static inline void snd_dma_noncontig_iter_set(struct snd_dma_buffer *dmab,
603 					      struct sg_page_iter *piter,
604 					      size_t offset)
605 {
606 	struct sg_table *sgt = dmab->private_data;
607 
608 	__sg_page_iter_start(piter, sgt->sgl, sgt->orig_nents,
609 			     offset >> PAGE_SHIFT);
610 }
611 
612 static dma_addr_t snd_dma_noncontig_get_addr(struct snd_dma_buffer *dmab,
613 					     size_t offset)
614 {
615 	struct sg_dma_page_iter iter;
616 
617 	snd_dma_noncontig_iter_set(dmab, &iter.base, offset);
618 	__sg_page_iter_dma_next(&iter);
619 	return sg_page_iter_dma_address(&iter) + offset % PAGE_SIZE;
620 }
621 
622 static struct page *snd_dma_noncontig_get_page(struct snd_dma_buffer *dmab,
623 					       size_t offset)
624 {
625 	struct sg_page_iter iter;
626 
627 	snd_dma_noncontig_iter_set(dmab, &iter, offset);
628 	__sg_page_iter_next(&iter);
629 	return sg_page_iter_page(&iter);
630 }
631 
632 static unsigned int
633 snd_dma_noncontig_get_chunk_size(struct snd_dma_buffer *dmab,
634 				 unsigned int ofs, unsigned int size)
635 {
636 	struct sg_dma_page_iter iter;
637 	unsigned int start, end;
638 	unsigned long addr;
639 
640 	start = ALIGN_DOWN(ofs, PAGE_SIZE);
641 	end = ofs + size - 1; /* the last byte address */
642 	snd_dma_noncontig_iter_set(dmab, &iter.base, start);
643 	if (!__sg_page_iter_dma_next(&iter))
644 		return 0;
645 	/* check page continuity */
646 	addr = sg_page_iter_dma_address(&iter);
647 	for (;;) {
648 		start += PAGE_SIZE;
649 		if (start > end)
650 			break;
651 		addr += PAGE_SIZE;
652 		if (!__sg_page_iter_dma_next(&iter) ||
653 		    sg_page_iter_dma_address(&iter) != addr)
654 			return start - ofs;
655 	}
656 	/* ok, all on continuous pages */
657 	return size;
658 }
659 
660 static const struct snd_malloc_ops snd_dma_noncontig_ops = {
661 	.alloc = snd_dma_noncontig_alloc,
662 	.free = snd_dma_noncontig_free,
663 	.mmap = snd_dma_noncontig_mmap,
664 	.sync = snd_dma_noncontig_sync,
665 	.get_addr = snd_dma_noncontig_get_addr,
666 	.get_page = snd_dma_noncontig_get_page,
667 	.get_chunk_size = snd_dma_noncontig_get_chunk_size,
668 };
669 
670 /* x86-specific SG-buffer with WC pages */
671 #ifdef CONFIG_SND_DMA_SGBUF
672 #define sg_wc_address(it) ((unsigned long)page_address(sg_page_iter_page(it)))
673 
674 static void *snd_dma_sg_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
675 {
676 	void *p = snd_dma_noncontig_alloc(dmab, size);
677 	struct sg_table *sgt = dmab->private_data;
678 	struct sg_page_iter iter;
679 
680 	if (!p)
681 		return NULL;
682 	if (dmab->dev.type != SNDRV_DMA_TYPE_DEV_WC_SG)
683 		return p;
684 	for_each_sgtable_page(sgt, &iter, 0)
685 		set_memory_wc(sg_wc_address(&iter), 1);
686 	return p;
687 }
688 
689 static void snd_dma_sg_wc_free(struct snd_dma_buffer *dmab)
690 {
691 	struct sg_table *sgt = dmab->private_data;
692 	struct sg_page_iter iter;
693 
694 	for_each_sgtable_page(sgt, &iter, 0)
695 		set_memory_wb(sg_wc_address(&iter), 1);
696 	snd_dma_noncontig_free(dmab);
697 }
698 
699 static int snd_dma_sg_wc_mmap(struct snd_dma_buffer *dmab,
700 			      struct vm_area_struct *area)
701 {
702 	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
703 	return dma_mmap_noncontiguous(dmab->dev.dev, area,
704 				      dmab->bytes, dmab->private_data);
705 }
706 
707 static const struct snd_malloc_ops snd_dma_sg_wc_ops = {
708 	.alloc = snd_dma_sg_wc_alloc,
709 	.free = snd_dma_sg_wc_free,
710 	.mmap = snd_dma_sg_wc_mmap,
711 	.sync = snd_dma_noncontig_sync,
712 	.get_addr = snd_dma_noncontig_get_addr,
713 	.get_page = snd_dma_noncontig_get_page,
714 	.get_chunk_size = snd_dma_noncontig_get_chunk_size,
715 };
716 
717 /* Fallback SG-buffer allocations for x86 */
718 struct snd_dma_sg_fallback {
719 	bool use_dma_alloc_coherent;
720 	size_t count;
721 	struct page **pages;
722 	/* DMA address array; the first page contains #pages in ~PAGE_MASK */
723 	dma_addr_t *addrs;
724 };
725 
726 static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab,
727 				       struct snd_dma_sg_fallback *sgbuf)
728 {
729 	size_t i, size;
730 
731 	if (sgbuf->pages && sgbuf->addrs) {
732 		i = 0;
733 		while (i < sgbuf->count) {
734 			if (!sgbuf->pages[i] || !sgbuf->addrs[i])
735 				break;
736 			size = sgbuf->addrs[i] & ~PAGE_MASK;
737 			if (WARN_ON(!size))
738 				break;
739 			if (sgbuf->use_dma_alloc_coherent)
740 				dma_free_coherent(dmab->dev.dev, size << PAGE_SHIFT,
741 						  page_address(sgbuf->pages[i]),
742 						  sgbuf->addrs[i] & PAGE_MASK);
743 			else
744 				do_free_pages(page_address(sgbuf->pages[i]),
745 					      size << PAGE_SHIFT, false);
746 			i += size;
747 		}
748 	}
749 	kvfree(sgbuf->pages);
750 	kvfree(sgbuf->addrs);
751 	kfree(sgbuf);
752 }
753 
754 static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
755 {
756 	struct snd_dma_sg_fallback *sgbuf;
757 	struct page **pagep, *curp;
758 	size_t chunk, npages;
759 	dma_addr_t *addrp;
760 	dma_addr_t addr;
761 	void *p;
762 
763 	/* correct the type */
764 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_SG)
765 		dmab->dev.type = SNDRV_DMA_TYPE_DEV_SG_FALLBACK;
766 	else if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
767 		dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
768 
769 	sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
770 	if (!sgbuf)
771 		return NULL;
772 	sgbuf->use_dma_alloc_coherent = cpu_feature_enabled(X86_FEATURE_XENPV);
773 	size = PAGE_ALIGN(size);
774 	sgbuf->count = size >> PAGE_SHIFT;
775 	sgbuf->pages = kvcalloc(sgbuf->count, sizeof(*sgbuf->pages), GFP_KERNEL);
776 	sgbuf->addrs = kvcalloc(sgbuf->count, sizeof(*sgbuf->addrs), GFP_KERNEL);
777 	if (!sgbuf->pages || !sgbuf->addrs)
778 		goto error;
779 
780 	pagep = sgbuf->pages;
781 	addrp = sgbuf->addrs;
782 	chunk = (PAGE_SIZE - 1) << PAGE_SHIFT; /* to fit in low bits in addrs */
783 	while (size > 0) {
784 		chunk = min(size, chunk);
785 		if (sgbuf->use_dma_alloc_coherent)
786 			p = dma_alloc_coherent(dmab->dev.dev, chunk, &addr, DEFAULT_GFP);
787 		else
788 			p = do_alloc_pages(dmab->dev.dev, chunk, &addr, false);
789 		if (!p) {
790 			if (chunk <= PAGE_SIZE)
791 				goto error;
792 			chunk >>= 1;
793 			chunk = PAGE_SIZE << get_order(chunk);
794 			continue;
795 		}
796 
797 		size -= chunk;
798 		/* fill pages */
799 		npages = chunk >> PAGE_SHIFT;
800 		*addrp = npages; /* store in lower bits */
801 		curp = virt_to_page(p);
802 		while (npages--) {
803 			*pagep++ = curp++;
804 			*addrp++ |= addr;
805 			addr += PAGE_SIZE;
806 		}
807 	}
808 
809 	p = vmap(sgbuf->pages, sgbuf->count, VM_MAP, PAGE_KERNEL);
810 	if (!p)
811 		goto error;
812 
813 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
814 		set_pages_array_wc(sgbuf->pages, sgbuf->count);
815 
816 	dmab->private_data = sgbuf;
817 	/* store the first page address for convenience */
818 	dmab->addr = sgbuf->addrs[0] & PAGE_MASK;
819 	return p;
820 
821  error:
822 	__snd_dma_sg_fallback_free(dmab, sgbuf);
823 	return NULL;
824 }
825 
826 static void snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab)
827 {
828 	struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
829 
830 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
831 		set_pages_array_wb(sgbuf->pages, sgbuf->count);
832 	vunmap(dmab->area);
833 	__snd_dma_sg_fallback_free(dmab, dmab->private_data);
834 }
835 
836 static dma_addr_t snd_dma_sg_fallback_get_addr(struct snd_dma_buffer *dmab,
837 					       size_t offset)
838 {
839 	struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
840 	size_t index = offset >> PAGE_SHIFT;
841 
842 	return (sgbuf->addrs[index] & PAGE_MASK) | (offset & ~PAGE_MASK);
843 }
844 
845 static int snd_dma_sg_fallback_mmap(struct snd_dma_buffer *dmab,
846 				    struct vm_area_struct *area)
847 {
848 	struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
849 
850 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
851 		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
852 	return vm_map_pages(area, sgbuf->pages, sgbuf->count);
853 }
854 
855 static const struct snd_malloc_ops snd_dma_sg_fallback_ops = {
856 	.alloc = snd_dma_sg_fallback_alloc,
857 	.free = snd_dma_sg_fallback_free,
858 	.mmap = snd_dma_sg_fallback_mmap,
859 	.get_addr = snd_dma_sg_fallback_get_addr,
860 	/* reuse vmalloc helpers */
861 	.get_page = snd_dma_vmalloc_get_page,
862 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
863 };
864 #endif /* CONFIG_SND_DMA_SGBUF */
865 
866 /*
867  * Non-coherent pages allocator
868  */
869 static void *snd_dma_noncoherent_alloc(struct snd_dma_buffer *dmab, size_t size)
870 {
871 	void *p;
872 
873 	p = dma_alloc_noncoherent(dmab->dev.dev, size, &dmab->addr,
874 				  dmab->dev.dir, DEFAULT_GFP);
875 	if (p)
876 		dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->addr);
877 	return p;
878 }
879 
880 static void snd_dma_noncoherent_free(struct snd_dma_buffer *dmab)
881 {
882 	dma_free_noncoherent(dmab->dev.dev, dmab->bytes, dmab->area,
883 			     dmab->addr, dmab->dev.dir);
884 }
885 
886 static int snd_dma_noncoherent_mmap(struct snd_dma_buffer *dmab,
887 				    struct vm_area_struct *area)
888 {
889 	area->vm_page_prot = vm_get_page_prot(area->vm_flags);
890 	return dma_mmap_pages(dmab->dev.dev, area,
891 			      area->vm_end - area->vm_start,
892 			      virt_to_page(dmab->area));
893 }
894 
895 static void snd_dma_noncoherent_sync(struct snd_dma_buffer *dmab,
896 				     enum snd_dma_sync_mode mode)
897 {
898 	if (mode == SNDRV_DMA_SYNC_CPU) {
899 		if (dmab->dev.dir != DMA_TO_DEVICE)
900 			dma_sync_single_for_cpu(dmab->dev.dev, dmab->addr,
901 						dmab->bytes, dmab->dev.dir);
902 	} else {
903 		if (dmab->dev.dir != DMA_FROM_DEVICE)
904 			dma_sync_single_for_device(dmab->dev.dev, dmab->addr,
905 						   dmab->bytes, dmab->dev.dir);
906 	}
907 }
908 
909 static const struct snd_malloc_ops snd_dma_noncoherent_ops = {
910 	.alloc = snd_dma_noncoherent_alloc,
911 	.free = snd_dma_noncoherent_free,
912 	.mmap = snd_dma_noncoherent_mmap,
913 	.sync = snd_dma_noncoherent_sync,
914 };
915 
916 #endif /* CONFIG_HAS_DMA */
917 
918 /*
919  * Entry points
920  */
921 static const struct snd_malloc_ops *snd_dma_ops[] = {
922 	[SNDRV_DMA_TYPE_CONTINUOUS] = &snd_dma_continuous_ops,
923 	[SNDRV_DMA_TYPE_VMALLOC] = &snd_dma_vmalloc_ops,
924 #ifdef CONFIG_HAS_DMA
925 	[SNDRV_DMA_TYPE_DEV] = &snd_dma_dev_ops,
926 	[SNDRV_DMA_TYPE_DEV_WC] = &snd_dma_wc_ops,
927 	[SNDRV_DMA_TYPE_NONCONTIG] = &snd_dma_noncontig_ops,
928 	[SNDRV_DMA_TYPE_NONCOHERENT] = &snd_dma_noncoherent_ops,
929 #ifdef CONFIG_SND_DMA_SGBUF
930 	[SNDRV_DMA_TYPE_DEV_WC_SG] = &snd_dma_sg_wc_ops,
931 #endif
932 #ifdef CONFIG_GENERIC_ALLOCATOR
933 	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
934 #endif /* CONFIG_GENERIC_ALLOCATOR */
935 #ifdef CONFIG_SND_DMA_SGBUF
936 	[SNDRV_DMA_TYPE_DEV_SG_FALLBACK] = &snd_dma_sg_fallback_ops,
937 	[SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK] = &snd_dma_sg_fallback_ops,
938 #endif
939 #endif /* CONFIG_HAS_DMA */
940 };
941 
942 static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab)
943 {
944 	if (WARN_ON_ONCE(!dmab))
945 		return NULL;
946 	if (WARN_ON_ONCE(dmab->dev.type <= SNDRV_DMA_TYPE_UNKNOWN ||
947 			 dmab->dev.type >= ARRAY_SIZE(snd_dma_ops)))
948 		return NULL;
949 	return snd_dma_ops[dmab->dev.type];
950 }
951