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Commit 05503214 authored by Nicolin Chen's avatar Nicolin Chen Committed by Takashi Iwai
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ALSA: Add SoC on-chip internal ram support for DMA buffer allocation 



Now it's quite common that an SoC contains its on-chip internal RAM.
By using this RAM space for DMA buffer during audio playback/record,
we can shutdown the voltage for external RAM to save power.

So add new DEV type with iram malloc()/free() and accordingly modify
current default mmap() for the iram circumstance.

Signed-off-by: default avatarNicolin Chen <b42378@freescale.com>
Reviewed-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 861e66d3

include/sound/memalloc.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ struct snd_dma_device { 
#else

#define SNDRV_DMA_TYPE_DEV_SG	SNDRV_DMA_TYPE_DEV /* no SG-buf support */

#endif

#define SNDRV_DMA_TYPE_DEV_IRAM		4	/* generic device iram-buffer */



/*

 * info for buffer allocation

sound/core/memalloc.c

+52 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/seq_file.h>

#include <asm/uaccess.h>

#include <linux/dma-mapping.h>

#include <linux/genalloc.h>

#include <linux/moduleparam.h>

#include <linux/mutex.h>

#include <sound/memalloc.h>
@@ -157,6 +158,46 @@ static void snd_free_dev_pages(struct device *dev, size_t size, void *ptr, 
	dec_snd_pages(pg);

	dma_free_coherent(dev, PAGE_SIZE << pg, ptr, dma);

}



/**

 * 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

 */

void snd_malloc_dev_iram(struct snd_dma_buffer *dmab, size_t size)

{

	struct device *dev = dmab->dev.dev;

	struct gen_pool *pool = NULL;



	if (dev->of_node)

		pool = of_get_named_gen_pool(dev->of_node, "iram", 0);



	if (!pool)

		return;



	/* Assign the pool into private_data field */

	dmab->private_data = pool;



	dmab->area = (void *)gen_pool_alloc(pool, size);

	if (!dmab->area)

		return;



	dmab->addr = gen_pool_virt_to_phys(pool, (unsigned long)dmab->area);

}



/**

 * snd_free_dev_iram - free allocated specific memory from on-chip internal ram

 * @dmab: buffer allocation record to store the allocated data

 */

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_HAS_DMA */



/*
@@ -197,6 +238,14 @@ int snd_dma_alloc_pages(int type, struct device *device, size_t size, 
		dmab->addr = 0;

		break;

#ifdef CONFIG_HAS_DMA

	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;

	case SNDRV_DMA_TYPE_DEV:

		dmab->area = snd_malloc_dev_pages(device, size, &dmab->addr);

		break;
@@ -269,6 +318,9 @@ void snd_dma_free_pages(struct snd_dma_buffer *dmab) 
		snd_free_pages(dmab->area, dmab->bytes);

		break;

#ifdef CONFIG_HAS_DMA

	case SNDRV_DMA_TYPE_DEV_IRAM:

		snd_free_dev_iram(dmab);

		break;

	case SNDRV_DMA_TYPE_DEV:

		snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);

		break;

sound/core/pcm_native.c

+6 −0
Original line number Diff line number Diff line
@@ -3199,6 +3199,12 @@ int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream, 
			     struct vm_area_struct *area)

{

	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;

	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);

	}

#ifdef ARCH_HAS_DMA_MMAP_COHERENT

	if (!substream->ops->page &&

	    substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)