6 files changed, 322 insertions, 223 deletions

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 966bef5acc75..ad68bcdf82cf 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -15,99 +15,27 @@
 #include <asm/set_memory.h>
 #endif
 #include <sound/memalloc.h>
+#include "memalloc_local.h"
 
-/*
- *
- *  Bus-specific memory allocators
- *
- */
+static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab);
 
-#ifdef CONFIG_HAS_DMA
-/* allocate the coherent DMA pages */
-static void snd_malloc_dev_pages(struct snd_dma_buffer *dmab, size_t size)
-{
-	gfp_t gfp_flags;
-
-	gfp_flags = GFP_KERNEL
-		| __GFP_COMP	/* compound page lets parts be mapped */
-		| __GFP_NORETRY /* don't trigger OOM-killer */
-		| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
-	dmab->area = dma_alloc_coherent(dmab->dev.dev, size, &dmab->addr,
-					gfp_flags);
-#ifdef CONFIG_X86
-	if (dmab->area && dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
-		set_memory_wc((unsigned long)dmab->area,
-			      PAGE_ALIGN(size) >> PAGE_SHIFT);
-#endif
-}
-
-/* free the coherent DMA pages */
-static void snd_free_dev_pages(struct snd_dma_buffer *dmab)
+/* a cast to gfp flag from the dev pointer; for CONTINUOUS and VMALLOC types */
+static inline gfp_t snd_mem_get_gfp_flags(const struct snd_dma_buffer *dmab,
+					  gfp_t default_gfp)
 {
-#ifdef CONFIG_X86
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
-		set_memory_wb((unsigned long)dmab->area,
-			      PAGE_ALIGN(dmab->bytes) >> PAGE_SHIFT);
-#endif
-	dma_free_coherent(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
+	if (!dmab->dev.dev)
+		return default_gfp;
+	else
+		return (__force gfp_t)(unsigned long)dmab->dev.dev;
 }
 
-#ifdef CONFIG_GENERIC_ALLOCATOR
-/**
- * snd_malloc_dev_iram - allocate memory from on-chip internal ram
- * @dmab: buffer allocation record to store the allocated data
- * @size: number of bytes to allocate from the iram
- *
- * This function requires iram phandle provided via of_node
- */
-static void snd_malloc_dev_iram(struct snd_dma_buffer *dmab, size_t size)
+static int __snd_dma_alloc_pages(struct snd_dma_buffer *dmab, size_t size)
 {
-	struct device *dev = dmab->dev.dev;
-	struct gen_pool *pool = NULL;
-
-	dmab->area = NULL;
-	dmab->addr = 0;
-
-	if (dev->of_node)
-		pool = of_gen_pool_get(dev->of_node, "iram", 0);
-
-	if (!pool)
-		return;
-
-	/* Assign the pool into private_data field */
-	dmab->private_data = pool;
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
 
-	dmab->area = gen_pool_dma_alloc_align(pool, size, &dmab->addr,
-					PAGE_SIZE);
-}
-
-/**
- * snd_free_dev_iram - free allocated specific memory from on-chip internal ram
- * @dmab: buffer allocation record to store the allocated data
- */
-static void snd_free_dev_iram(struct snd_dma_buffer *dmab)
-{
-	struct gen_pool *pool = dmab->private_data;
-
-	if (pool && dmab->area)
-		gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
-}
-#endif /* CONFIG_GENERIC_ALLOCATOR */
-#endif /* CONFIG_HAS_DMA */
-
-/*
- *
- *  ALSA generic memory management
- *
- */
-
-static inline gfp_t snd_mem_get_gfp_flags(const struct device *dev,
-					  gfp_t default_gfp)
-{
-	if (!dev)
-		return default_gfp;
-	else
-		return (__force gfp_t)(unsigned long)dev;
+	if (WARN_ON_ONCE(!ops || !ops->alloc))
+		return -EINVAL;
+	return ops->alloc(dmab, size);
 }
 
 /**
@@ -126,7 +54,7 @@ static inline gfp_t snd_mem_get_gfp_flags(const struct device *dev,
 int snd_dma_alloc_pages(int type, struct device *device, size_t size,
 			struct snd_dma_buffer *dmab)
 {
-	gfp_t gfp;
+	int err;
 
 	if (WARN_ON(!size))
 		return -ENXIO;
@@ -140,43 +68,10 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size,
 	dmab->area = NULL;
 	dmab->addr = 0;
 	dmab->private_data = NULL;
-	switch (type) {
-	case SNDRV_DMA_TYPE_CONTINUOUS:
-		gfp = snd_mem_get_gfp_flags(device, GFP_KERNEL);
-		dmab->area = alloc_pages_exact(size, gfp);
-		break;
-	case SNDRV_DMA_TYPE_VMALLOC:
-		gfp = snd_mem_get_gfp_flags(device, GFP_KERNEL | __GFP_HIGHMEM);
-		dmab->area = __vmalloc(size, gfp);
-		break;
-#ifdef CONFIG_HAS_DMA
-#ifdef CONFIG_GENERIC_ALLOCATOR
-	case SNDRV_DMA_TYPE_DEV_IRAM:
-		snd_malloc_dev_iram(dmab, size);
-		if (dmab->area)
-			break;
-		/* Internal memory might have limited size and no enough space,
-		 * so if we fail to malloc, try to fetch memory traditionally.
-		 */
-		dmab->dev.type = SNDRV_DMA_TYPE_DEV;
-		fallthrough;
-#endif /* CONFIG_GENERIC_ALLOCATOR */
-	case SNDRV_DMA_TYPE_DEV:
-	case SNDRV_DMA_TYPE_DEV_UC:
-		snd_malloc_dev_pages(dmab, size);
-		break;
-#endif
-#ifdef CONFIG_SND_DMA_SGBUF
-	case SNDRV_DMA_TYPE_DEV_SG:
-	case SNDRV_DMA_TYPE_DEV_UC_SG:
-		snd_malloc_sgbuf_pages(device, size, dmab, NULL);
-		break;
-#endif
-	default:
-		pr_err("snd-malloc: invalid device type %d\n", type);
-		return -ENXIO;
-	}
-	if (! dmab->area)
+	err = __snd_dma_alloc_pages(dmab, size);
+	if (err < 0)
+		return err;
+	if (!dmab->area)
 		return -ENOMEM;
 	dmab->bytes = size;
 	return 0;
@@ -217,7 +112,6 @@ int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
 }
 EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
 
-
 /**
  * snd_dma_free_pages - release the allocated buffer
  * @dmab: the buffer allocation record to release
@@ -226,32 +120,235 @@ EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
  */
 void snd_dma_free_pages(struct snd_dma_buffer *dmab)
 {
-	switch (dmab->dev.type) {
-	case SNDRV_DMA_TYPE_CONTINUOUS:
-		free_pages_exact(dmab->area, dmab->bytes);
-		break;
-	case SNDRV_DMA_TYPE_VMALLOC:
-		vfree(dmab->area);
-		break;
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
+
+	if (ops && ops->free)
+		ops->free(dmab);
+}
+EXPORT_SYMBOL(snd_dma_free_pages);
+
+/**
+ * snd_sgbuf_get_addr - return the physical address at the corresponding offset
+ * @dmab: buffer allocation information
+ * @offset: offset in the ring buffer
+ */
+dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset)
+{
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
+
+	if (ops && ops->get_addr)
+		return ops->get_addr(dmab, offset);
+	else
+		return dmab->addr + offset;
+}
+EXPORT_SYMBOL(snd_sgbuf_get_addr);
+
+/**
+ * snd_sgbuf_get_page - return the physical page at the corresponding offset
+ * @dmab: buffer allocation information
+ * @offset: offset in the ring buffer
+ */
+struct page *snd_sgbuf_get_page(struct snd_dma_buffer *dmab, size_t offset)
+{
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
+
+	if (ops && ops->get_page)
+		return ops->get_page(dmab, offset);
+	else
+		return virt_to_page(dmab->area + offset);
+}
+EXPORT_SYMBOL(snd_sgbuf_get_page);
+
+/**
+ * snd_sgbuf_get_chunk_size - compute the max chunk size with continuous pages
+ *	on sg-buffer
+ * @dmab: buffer allocation information
+ * @ofs: offset in the ring buffer
+ * @size: the requested size
+ */
+unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
+				      unsigned int ofs, unsigned int size)
+{
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
+
+	if (ops && ops->get_chunk_size)
+		return ops->get_chunk_size(dmab, ofs, size);
+	else
+		return size;
+}
+EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
+
+/*
+ * Continuous pages allocator
+ */
+static int snd_dma_continuous_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	gfp_t gfp = snd_mem_get_gfp_flags(dmab, GFP_KERNEL);
+
+	dmab->area = alloc_pages_exact(size, gfp);
+	return 0;
+}
+
+static void snd_dma_continuous_free(struct snd_dma_buffer *dmab)
+{
+	free_pages_exact(dmab->area, dmab->bytes);
+}
+
+static const struct snd_malloc_ops snd_dma_continuous_ops = {
+	.alloc = snd_dma_continuous_alloc,
+	.free = snd_dma_continuous_free,
+};
+
+/*
+ * VMALLOC allocator
+ */
+static int snd_dma_vmalloc_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	gfp_t gfp = snd_mem_get_gfp_flags(dmab, GFP_KERNEL | __GFP_HIGHMEM);
+
+	dmab->area = __vmalloc(size, gfp);
+	return 0;
+}
+
+static void snd_dma_vmalloc_free(struct snd_dma_buffer *dmab)
+{
+	vfree(dmab->area);
+}
+
+static dma_addr_t snd_dma_vmalloc_get_addr(struct snd_dma_buffer *dmab,
+					   size_t offset)
+{
+	return page_to_phys(vmalloc_to_page(dmab->area + offset)) +
+		offset % PAGE_SIZE;
+}
+
+static struct page *snd_dma_vmalloc_get_page(struct snd_dma_buffer *dmab,
+					     size_t offset)
+{
+	return vmalloc_to_page(dmab->area + offset);
+}
+
+static unsigned int
+snd_dma_vmalloc_get_chunk_size(struct snd_dma_buffer *dmab,
+			       unsigned int ofs, unsigned int size)
+{
+	ofs %= PAGE_SIZE;
+	size += ofs;
+	if (size > PAGE_SIZE)
+		size = PAGE_SIZE;
+	return size - ofs;
+}
+
+static const struct snd_malloc_ops snd_dma_vmalloc_ops = {
+	.alloc = snd_dma_vmalloc_alloc,
+	.free = snd_dma_vmalloc_free,
+	.get_addr = snd_dma_vmalloc_get_addr,
+	.get_page = snd_dma_vmalloc_get_page,
+	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
+};
+
 #ifdef CONFIG_HAS_DMA
+/*
+ * IRAM allocator
+ */
 #ifdef CONFIG_GENERIC_ALLOCATOR
-	case SNDRV_DMA_TYPE_DEV_IRAM:
-		snd_free_dev_iram(dmab);
-		break;
+static int snd_dma_iram_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	struct device *dev = dmab->dev.dev;
+	struct gen_pool *pool;
+
+	if (dev->of_node) {
+		pool = of_gen_pool_get(dev->of_node, "iram", 0);
+		/* Assign the pool into private_data field */
+		dmab->private_data = pool;
+
+		dmab->area = gen_pool_dma_alloc_align(pool, size, &dmab->addr,
+						      PAGE_SIZE);
+		if (dmab->area)
+			return 0;
+	}
+
+	/* Internal memory might have limited size and no enough space,
+	 * so if we fail to malloc, try to fetch memory traditionally.
+	 */
+	dmab->dev.type = SNDRV_DMA_TYPE_DEV;
+	return __snd_dma_alloc_pages(dmab, size);
+}
+
+static void snd_dma_iram_free(struct snd_dma_buffer *dmab)
+{
+	struct gen_pool *pool = dmab->private_data;
+
+	if (pool && dmab->area)
+		gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
+}
+
+static const struct snd_malloc_ops snd_dma_iram_ops = {
+	.alloc = snd_dma_iram_alloc,
+	.free = snd_dma_iram_free,
+};
 #endif /* CONFIG_GENERIC_ALLOCATOR */
-	case SNDRV_DMA_TYPE_DEV:
-	case SNDRV_DMA_TYPE_DEV_UC:
-		snd_free_dev_pages(dmab);
-		break;
+
+/*
+ * Coherent device pages allocator
+ */
+static int snd_dma_dev_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	gfp_t gfp_flags;
+
+	gfp_flags = GFP_KERNEL
+		| __GFP_COMP	/* compound page lets parts be mapped */
+		| __GFP_NORETRY /* don't trigger OOM-killer */
+		| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
+	dmab->area = dma_alloc_coherent(dmab->dev.dev, size, &dmab->addr,
+					gfp_flags);
+#ifdef CONFIG_X86
+	if (dmab->area && dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
+		set_memory_wc((unsigned long)dmab->area,
+			      PAGE_ALIGN(size) >> PAGE_SHIFT);
 #endif
+	return 0;
+}
+
+static void snd_dma_dev_free(struct snd_dma_buffer *dmab)
+{
+#ifdef CONFIG_X86
+	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
+		set_memory_wb((unsigned long)dmab->area,
+			      PAGE_ALIGN(dmab->bytes) >> PAGE_SHIFT);
+#endif
+	dma_free_coherent(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
+}
+
+static const struct snd_malloc_ops snd_dma_dev_ops = {
+	.alloc = snd_dma_dev_alloc,
+	.free = snd_dma_dev_free,
+};
+#endif /* CONFIG_HAS_DMA */
+
+/*
+ * Entry points
+ */
+static const struct snd_malloc_ops *dma_ops[] = {
+	[SNDRV_DMA_TYPE_CONTINUOUS] = &snd_dma_continuous_ops,
+	[SNDRV_DMA_TYPE_VMALLOC] = &snd_dma_vmalloc_ops,
+#ifdef CONFIG_HAS_DMA
+	[SNDRV_DMA_TYPE_DEV] = &snd_dma_dev_ops,
+	[SNDRV_DMA_TYPE_DEV_UC] = &snd_dma_dev_ops,
+#ifdef CONFIG_GENERIC_ALLOCATOR
+	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
+#endif /* CONFIG_GENERIC_ALLOCATOR */
+#endif /* CONFIG_HAS_DMA */
 #ifdef CONFIG_SND_DMA_SGBUF
-	case SNDRV_DMA_TYPE_DEV_SG:
-	case SNDRV_DMA_TYPE_DEV_UC_SG:
-		snd_free_sgbuf_pages(dmab);
-		break;
+	[SNDRV_DMA_TYPE_DEV_SG] = &snd_dma_sg_ops,
+	[SNDRV_DMA_TYPE_DEV_UC_SG] = &snd_dma_sg_ops,
 #endif
-	default:
-		pr_err("snd-malloc: invalid device type %d\n", dmab->dev.type);
-	}
+};
+
+static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab)
+{
+	if (WARN_ON_ONCE(dmab->dev.type <= SNDRV_DMA_TYPE_UNKNOWN ||
+			 dmab->dev.type >= ARRAY_SIZE(dma_ops)))
+		return NULL;
+	return dma_ops[dmab->dev.type];
 }
-EXPORT_SYMBOL(snd_dma_free_pages);
diff --git a/sound/core/memalloc_local.h b/sound/core/memalloc_local.h
new file mode 100644
index 000000000000..fe55416253bf
--- /dev/null
+++ b/sound/core/memalloc_local.h
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef __MEMALLOC_LOCAL_H
+#define __MEMALLOC_LOCAL_H
+
+struct snd_malloc_ops {
+	int (*alloc)(struct snd_dma_buffer *dmab, size_t size);
+	void (*free)(struct snd_dma_buffer *dmab);
+	dma_addr_t (*get_addr)(struct snd_dma_buffer *dmab, size_t offset);
+	struct page *(*get_page)(struct snd_dma_buffer *dmab, size_t offset);
+	unsigned int (*get_chunk_size)(struct snd_dma_buffer *dmab,
+				       unsigned int ofs, unsigned int size);
+};
+
+#ifdef CONFIG_SND_DMA_SGBUF
+extern const struct snd_malloc_ops snd_dma_sg_ops;
+#endif
+
+#endif /* __MEMALLOC_LOCAL_H */
diff --git a/sound/core/pcm_local.h b/sound/core/pcm_local.h
index e3b3558aeab6..fe9689b8a6a6 100644
--- a/sound/core/pcm_local.h
+++ b/sound/core/pcm_local.h
@@ -65,11 +65,6 @@ void __snd_pcm_xrun(struct snd_pcm_substream *substream);
 void snd_pcm_group_init(struct snd_pcm_group *group);
 void snd_pcm_sync_stop(struct snd_pcm_substream *substream, bool sync_irq);
 
-#ifdef CONFIG_SND_DMA_SGBUF
-struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream,
-				    unsigned long offset);
-#endif
-
 #define PCM_RUNTIME_CHECK(sub) snd_BUG_ON(!(sub) || !(sub)->runtime)
 
 /* loop over all PCM substreams */
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index 542a75babdee..d7621ed105bd 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -337,27 +337,6 @@ void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
 }
 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
- * @substream: the pcm substream instance
- * @offset: the buffer offset
- *
- * Used as the page callback of PCM ops.
- *
- * Return: The page struct at the given buffer offset. %NULL on failure.
- */
-struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
-{
-	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
-
-	unsigned int idx = offset >> PAGE_SHIFT;
-	if (idx >= (unsigned int)sgbuf->pages)
-		return NULL;
-	return sgbuf->page_table[idx];
-}
-#endif /* CONFIG_SND_DMA_SGBUF */
-
 /**
  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
  * @substream: the substream to allocate the DMA buffer to
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index eb468573f070..48d63dbb17ba 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3644,24 +3644,6 @@ static int snd_pcm_mmap_control(struct snd_pcm_substream *substream, struct file
 }
 #endif /* coherent mmap */
 
-static inline struct page *
-snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs)
-{
-	void *vaddr = substream->runtime->dma_area + ofs;
-
-	switch (substream->dma_buffer.dev.type) {
-#ifdef CONFIG_SND_DMA_SGBUF
-	case SNDRV_DMA_TYPE_DEV_SG:
-	case SNDRV_DMA_TYPE_DEV_UC_SG:
-		return snd_pcm_sgbuf_ops_page(substream, ofs);
-#endif /* CONFIG_SND_DMA_SGBUF */
-	case SNDRV_DMA_TYPE_VMALLOC:
-		return vmalloc_to_page(vaddr);
-	default:
-		return virt_to_page(vaddr);
-	}
-}
-
 /*
  * fault callback for mmapping a RAM page
  */
@@ -3683,7 +3665,7 @@ static vm_fault_t snd_pcm_mmap_data_fault(struct vm_fault *vmf)
 	if (substream->ops->page)
 		page = substream->ops->page(substream, offset);
 	else
-		page = snd_pcm_default_page_ops(substream, offset);
+		page = snd_sgbuf_get_page(snd_pcm_get_dma_buf(substream), offset);
 	if (!page)
 		return VM_FAULT_SIGBUS;
 	get_page(page);
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
index 29ddb76187e5..232cf3f1bcb3 100644
--- a/sound/core/sgbuf.c
+++ b/sound/core/sgbuf.c
@@ -10,20 +10,34 @@
 #include <linux/vmalloc.h>
 #include <linux/export.h>
 #include <sound/memalloc.h>
-
+#include "memalloc_local.h"
+
+struct snd_sg_page {
+	void *buf;
+	dma_addr_t addr;
+};
+
+struct snd_sg_buf {
+	int size;	/* allocated byte size */
+	int pages;	/* allocated pages */
+	int tblsize;	/* allocated table size */
+	struct snd_sg_page *table;	/* address table */
+	struct page **page_table;	/* page table (for vmap/vunmap) */
+	struct device *dev;
+};
 
 /* table entries are align to 32 */
 #define SGBUF_TBL_ALIGN		32
 #define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
 
-int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
+static void snd_dma_sg_free(struct snd_dma_buffer *dmab)
 {
 	struct snd_sg_buf *sgbuf = dmab->private_data;
 	struct snd_dma_buffer tmpb;
 	int i;
 
-	if (! sgbuf)
-		return -EINVAL;
+	if (!sgbuf)
+		return;
 
 	vunmap(dmab->area);
 	dmab->area = NULL;
@@ -45,15 +59,11 @@ int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
 	kfree(sgbuf->page_table);
 	kfree(sgbuf);
 	dmab->private_data = NULL;
-	
-	return 0;
 }
 
 #define MAX_ALLOC_PAGES		32
 
-void *snd_malloc_sgbuf_pages(struct device *device,
-			     size_t size, struct snd_dma_buffer *dmab,
-			     size_t *res_size)
+static int snd_dma_sg_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
 	struct snd_sg_buf *sgbuf;
 	unsigned int i, pages, chunk, maxpages;
@@ -63,18 +73,16 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 	int type = SNDRV_DMA_TYPE_DEV;
 	pgprot_t prot = PAGE_KERNEL;
 
-	dmab->area = NULL;
-	dmab->addr = 0;
 	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
-	if (! sgbuf)
-		return NULL;
+	if (!sgbuf)
+		return -ENOMEM;
 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) {
 		type = SNDRV_DMA_TYPE_DEV_UC;
 #ifdef pgprot_noncached
 		prot = pgprot_noncached(PAGE_KERNEL);
 #endif
 	}
-	sgbuf->dev = device;
+	sgbuf->dev = dmab->dev.dev;
 	pages = snd_sgbuf_aligned_pages(size);
 	sgbuf->tblsize = sgbuf_align_table(pages);
 	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
@@ -94,12 +102,10 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 		if (chunk > maxpages)
 			chunk = maxpages;
 		chunk <<= PAGE_SHIFT;
-		if (snd_dma_alloc_pages_fallback(type, device,
+		if (snd_dma_alloc_pages_fallback(type, dmab->dev.dev,
 						 chunk, &tmpb) < 0) {
 			if (!sgbuf->pages)
 				goto _failed;
-			if (!res_size)
-				goto _failed;
 			size = sgbuf->pages * PAGE_SIZE;
 			break;
 		}
@@ -124,27 +130,42 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 	dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
 	if (! dmab->area)
 		goto _failed;
-	if (res_size)
-		*res_size = sgbuf->size;
-	return dmab->area;
+	return 0;
 
  _failed:
-	snd_free_sgbuf_pages(dmab); /* free the table */
-	return NULL;
+	snd_dma_sg_free(dmab); /* free the table */
+	return -ENOMEM;
 }
 
-/*
- * compute the max chunk size with continuous pages on sg-buffer
- */
-unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
-				      unsigned int ofs, unsigned int size)
+static dma_addr_t snd_dma_sg_get_addr(struct snd_dma_buffer *dmab,
+				      size_t offset)
+{
+	struct snd_sg_buf *sgbuf = dmab->private_data;
+	dma_addr_t addr;
+
+	addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
+	addr &= ~((dma_addr_t)PAGE_SIZE - 1);
+	return addr + offset % PAGE_SIZE;
+}
+
+static struct page *snd_dma_sg_get_page(struct snd_dma_buffer *dmab,
+					size_t offset)
+{
+	struct snd_sg_buf *sgbuf = dmab->private_data;
+	unsigned int idx = offset >> PAGE_SHIFT;
+
+	if (idx >= (unsigned int)sgbuf->pages)
+		return NULL;
+	return sgbuf->page_table[idx];
+}
+
+static unsigned int snd_dma_sg_get_chunk_size(struct snd_dma_buffer *dmab,
+					      unsigned int ofs,
+					      unsigned int size)
 {
 	struct snd_sg_buf *sg = dmab->private_data;
 	unsigned int start, end, pg;
 
-	if (!sg)
-		return size;
-
 	start = ofs >> PAGE_SHIFT;
 	end = (ofs + size - 1) >> PAGE_SHIFT;
 	/* check page continuity */
@@ -160,4 +181,11 @@ unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
 	/* ok, all on continuous pages */
 	return size;
 }
-EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
+
+const struct snd_malloc_ops snd_dma_sg_ops = {
+	.alloc = snd_dma_sg_alloc,
+	.free = snd_dma_sg_free,
+	.get_addr = snd_dma_sg_get_addr,
+	.get_page = snd_dma_sg_get_page,
+	.get_chunk_size = snd_dma_sg_get_chunk_size,
+};