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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: Nicolin Chen <b42378@freescale.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
hifive-unleashed-5.1
Nicolin Chen 2013-10-23 11:47:43 +08:00 committed by Takashi Iwai
parent 861e66d341
commit 055032142c
3 changed files with 59 additions and 0 deletions
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1
include/sound/memalloc.h
View File

@ -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

52
sound/core/memalloc.c
View File

@ -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;

6
sound/core/pcm_native.c
View File

@ -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)