[PATCH v2 2/3] ALSA: memalloc: Support for non-coherent page allocation

[Takashi Iwai]

Following after the addition of non-contiguous pages, this patch adds
the new contiguous non-coherent page allocation to the standard
memalloc helper.  Like the previous non-contig type, this non-coherent
type is also directional and requires the explicit sync, too.  Hence
the driver using this type of buffer may need to set
SNDRV_PCM_INFO_EXPLICIT_SYNC flag to the PCM hardware.info as well,
unless it's set up in the managed mode.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 include/sound/memalloc.h |  1 +
 sound/core/memalloc.c    | 47 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index 1457eba1ac53..0bdaa6753282 100644
--- a/include/sound/memalloc.h
+++ b/include/sound/memalloc.h
@@ -50,6 +50,7 @@ struct snd_dma_device {
 #endif
 #define SNDRV_DMA_TYPE_VMALLOC		7	/* vmalloc'ed buffer */
 #define SNDRV_DMA_TYPE_NONCONTIG	8	/* non-coherent SG buffer */
+#define SNDRV_DMA_TYPE_NONCOHERENT	9	/* non-coherent buffer */
 
 /*
  * info for buffer allocation
diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 11f9a68bf94c..99681e651223 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -560,6 +560,52 @@ static const struct snd_malloc_ops snd_dma_noncontig_ops = {
 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
 };
 
+/*
+ * Non-coherent pages allocator
+ */
+static void *snd_dma_noncoherent_alloc(struct snd_dma_buffer *dmab, size_t size)
+{
+	dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->dev.dir);
+	return dma_alloc_noncoherent(dmab->dev.dev, size, &dmab->addr,
+				     dmab->dev.dir, DEFAULT_GFP);
+}
+
+static void snd_dma_noncoherent_free(struct snd_dma_buffer *dmab)
+{
+	dma_free_noncoherent(dmab->dev.dev, dmab->bytes, dmab->area,
+			     dmab->addr, dmab->dev.dir);
+}
+
+static int snd_dma_noncoherent_mmap(struct snd_dma_buffer *dmab,
+				    struct vm_area_struct *area)
+{
+	area->vm_page_prot = vm_get_page_prot(area->vm_flags);
+	return dma_mmap_pages(dmab->dev.dev, area,
+			      area->vm_end - area->vm_start,
+			      virt_to_page(dmab->area));
+}
+
+static void snd_dma_noncoherent_sync(struct snd_dma_buffer *dmab,
+				     enum snd_dma_sync_mode mode)
+{
+	if (mode == SNDRV_DMA_SYNC_CPU) {
+		if (dmab->dev.dir != DMA_TO_DEVICE)
+			dma_sync_single_for_cpu(dmab->dev.dev, dmab->addr,
+						dmab->bytes, dmab->dev.dir);
+	} else {
+		if (dmab->dev.dir != DMA_FROM_DEVICE)
+			dma_sync_single_for_device(dmab->dev.dev, dmab->addr,
+						   dmab->bytes, dmab->dev.dir);
+	}
+}
+
+static const struct snd_malloc_ops snd_dma_noncoherent_ops = {
+	.alloc = snd_dma_noncoherent_alloc,
+	.free = snd_dma_noncoherent_free,
+	.mmap = snd_dma_noncoherent_mmap,
+	.sync = snd_dma_noncoherent_sync,
+};
+
 #endif /* CONFIG_HAS_DMA */
 
 /*
@@ -572,6 +618,7 @@ static const struct snd_malloc_ops *dma_ops[] = {
 	[SNDRV_DMA_TYPE_DEV] = &snd_dma_dev_ops,
 	[SNDRV_DMA_TYPE_DEV_WC] = &snd_dma_wc_ops,
 	[SNDRV_DMA_TYPE_NONCONTIG] = &snd_dma_noncontig_ops,
+	[SNDRV_DMA_TYPE_NONCOHERENT] = &snd_dma_noncoherent_ops,
 #ifdef CONFIG_GENERIC_ALLOCATOR
 	[SNDRV_DMA_TYPE_DEV_IRAM] = &snd_dma_iram_ops,
 #endif /* CONFIG_GENERIC_ALLOCATOR */
-- 
2.26.2