ALSA: core: Move mmap handler into memalloc ops

This patch moves the mmap handling code into the common memalloc
handler.  It allows us to reduce the memory-type specific code in PCM
code gracefully.

Link: https://lore.kernel.org/r/20210609162551.7842-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/memalloc.h

@@ -11,6 +11,7 @@
 
 struct device;
 struct page;
+struct vm_area_struct;
 
 /*
  * buffer device info
@@ -69,6 +70,8 @@ int snd_dma_alloc_pages(int type, struct device *dev, size_t size,
 int snd_dma_alloc_pages_fallback(int type, struct device *dev, size_t size,
                                  struct snd_dma_buffer *dmab);
 void snd_dma_free_pages(struct snd_dma_buffer *dmab);
+int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab,
+			struct vm_area_struct *area);
 
 dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset);
 struct page *snd_sgbuf_get_page(struct snd_dma_buffer *dmab, size_t offset);

sound/core/memalloc.c

@@ -127,6 +127,23 @@ void snd_dma_free_pages(struct snd_dma_buffer *dmab)
 }
 EXPORT_SYMBOL(snd_dma_free_pages);
 
+/**
+ * snd_dma_buffer_mmap - perform mmap of the given DMA buffer
+ * @dmab: buffer allocation information
+ * @area: VM area information
+ */
+int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab,
+			struct vm_area_struct *area)
+{
+	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
+
+	if (ops && ops->mmap)
+		return ops->mmap(dmab, area);
+	else
+		return -ENOENT;
+}
+EXPORT_SYMBOL(snd_dma_buffer_mmap);
+
 /**
  * snd_sgbuf_get_addr - return the physical address at the corresponding offset
  * @dmab: buffer allocation information
@@ -283,9 +300,20 @@ static void snd_dma_iram_free(struct snd_dma_buffer *dmab)
 		gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
 }
 
+static int snd_dma_iram_mmap(struct snd_dma_buffer *dmab,
+			     struct vm_area_struct *area)
+{
+	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+	return remap_pfn_range(area, area->vm_start,
+			       dmab->addr >> PAGE_SHIFT,
+			       area->vm_end - area->vm_start,
+			       area->vm_page_prot);
+}
+
 static const struct snd_malloc_ops snd_dma_iram_ops = {
 	.alloc = snd_dma_iram_alloc,
 	.free = snd_dma_iram_free,
+	.mmap = snd_dma_iram_mmap,
 };
 #endif /* CONFIG_GENERIC_ALLOCATOR */
 
@@ -320,9 +348,17 @@ static void snd_dma_dev_free(struct snd_dma_buffer *dmab)
 	dma_free_coherent(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
 }
 
+static int snd_dma_dev_mmap(struct snd_dma_buffer *dmab,
+			    struct vm_area_struct *area)
+{
+	return dma_mmap_coherent(dmab->dev.dev, area,
+				 dmab->area, dmab->addr, dmab->bytes);
+}
+
 static const struct snd_malloc_ops snd_dma_dev_ops = {
 	.alloc = snd_dma_dev_alloc,
 	.free = snd_dma_dev_free,
+	.mmap = snd_dma_dev_mmap,
 };
 #endif /* CONFIG_HAS_DMA */
 

sound/core/memalloc_local.h

@@ -9,6 +9,7 @@ struct snd_malloc_ops {
 	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);
+	int (*mmap)(struct snd_dma_buffer *dmab, struct vm_area_struct *area);
 };
 
 #ifdef CONFIG_SND_DMA_SGBUF

sound/core/pcm_native.c

@@ -3700,22 +3700,9 @@ int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
 			     struct vm_area_struct *area)
 {
 	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
-#ifdef CONFIG_GENERIC_ALLOCATOR
-	if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV_IRAM) {
-		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
-		return remap_pfn_range(area, area->vm_start,
-				substream->dma_buffer.addr >> PAGE_SHIFT,
-				area->vm_end - area->vm_start, area->vm_page_prot);
-	}
-#endif /* CONFIG_GENERIC_ALLOCATOR */
-	if (IS_ENABLED(CONFIG_HAS_DMA) && !substream->ops->page &&
-	    (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV ||
-	     substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV_UC))
-		return dma_mmap_coherent(substream->dma_buffer.dev.dev,
-					 area,
-					 substream->runtime->dma_area,
-					 substream->runtime->dma_addr,
-					 substream->runtime->dma_bytes);
+	if (!substream->ops->page &&
+	    !snd_dma_buffer_mmap(snd_pcm_get_dma_buf(substream), area))
+		return 0;
 	/* mmap with fault handler */
 	area->vm_ops = &snd_pcm_vm_ops_data_fault;
 	return 0;