[alsa-devel] [PATCH v3] ALSA: Add SoC on-chip internal memory support for DMA buffer allocation

[Takashi Iwai]

At Wed, 16 Oct 2013 18:16:02 +0800,
Nicolin Chen wrote:
> 
> Now it's quite common that an SoC contains its on-chip internal memory.
> By using this memory space for DMA buffer during audio playback/record,
> we can shutdown the voltage for external memory to save power.
> 
> Thus add new DEV type with iram malloc()/free() and accordingly modify
> current default mmap() for the iram circumstance.
> 
> Signed-off-by: Nicolin Chen <b42378 at freescale.com>

Try to build without CONFIG_OF once.  You'll get a few build errors
due to the duplicated labels in switch().  Please fix them and
resubmit.


thanks,

Takashi

> ---
> Changelog
> v2->v3:
>  * Moved iram specific mmap procedure out of ifdef ARCH_HAS_DMA_MMAP_COHERENT
> v1->v2:
>  * Added of_node check
>  * Dropped noops and unused physical addr in snd_free_dev_iram()
> 
> ---
>  include/sound/memalloc.h |  5 ++++
>  sound/core/memalloc.c    | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
>  sound/core/pcm_native.c  |  7 +++++
>  3 files changed, 84 insertions(+)
> 
> diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
> index cf15b82..b53443e 100644
> --- a/include/sound/memalloc.h
> +++ b/include/sound/memalloc.h
> @@ -52,6 +52,11 @@ struct snd_dma_device {
>  #else
>  #define SNDRV_DMA_TYPE_DEV_SG	SNDRV_DMA_TYPE_DEV /* no SG-buf support */
>  #endif
> +#ifdef CONFIG_OF
> +#define SNDRV_DMA_TYPE_DEV_IRAM		4	/* generic device iram-buffer */
> +#else
> +#define SNDRV_DMA_TYPE_DEV_IRAM		SNDRV_DMA_TYPE_DEV
> +#endif
>  
>  /*
>   * info for buffer allocation
> diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
> index bdf826f..2957938 100644
> --- a/sound/core/memalloc.c
> +++ b/sound/core/memalloc.c
> @@ -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 +158,61 @@ 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);
>  }
> +
> +#ifdef CONFIG_OF
> +/**
> + * snd_malloc_dev_iram - allocate memory from on-chip internal memory
> + * @dev: DMA device pointer
> + * @size: number of bytes to allocate from the iram
> + * @dma: dma-view physical address
> + *
> + * Return cpu-view address or NULL indicating allocating failure
> + *
> + * This function requires iram phandle provided via of_node
> + */
> +void *snd_malloc_dev_iram(struct device *dev, size_t size, dma_addr_t *dma)
> +{
> +	struct gen_pool *pool;
> +	unsigned long vaddr;
> +
> +	if (!dev->of_node)
> +		return NULL;
> +
> +	pool = of_get_named_gen_pool(dev->of_node, "iram", 0);
> +	if (!pool)
> +		return NULL;
> +
> +	vaddr = gen_pool_alloc(pool, size);
> +	if (!vaddr)
> +		return NULL;
> +
> +	*dma = gen_pool_virt_to_phys(pool, vaddr);
> +
> +	return (void *)vaddr;
> +}
> +
> +/**
> + * snd_free_dev_iram - free allocated specific memory from on-chip internal memory
> + * @dev: DMA device pointer
> + * @size: size in bytes of memory to free
> + * @ptr: cpu-view address returned from snd_malloc_dev_iram
> + *
> + * This function requires iram phandle provided via of_node
> + */
> +void snd_free_dev_iram(struct device *dev, size_t size, void *ptr)
> +{
> +	struct gen_pool *pool;
> +
> +	if (!dev->of_node)
> +		return;
> +
> +	pool = of_get_named_gen_pool(dev->of_node, "iram", 0);
> +	if (!pool)
> +		return;
> +
> +	gen_pool_free(pool, (unsigned long)ptr, size);
> +}
> +#endif /* CONFIG_OF */
>  #endif /* CONFIG_HAS_DMA */
>  
>  /*
> @@ -197,6 +253,17 @@ 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:
> +#ifdef CONFIG_OF
> +		dmab->area = snd_malloc_dev_iram(device, size, &dmab->addr);
> +		if (dmab->area)
> +			break;
> +#endif
> +		/*
> +		 * 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 +336,11 @@ 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:
> +#ifdef CONFIG_OF
> +		snd_free_dev_iram(dmab->dev.dev, dmab->bytes, dmab->area);
> +			break;
> +#endif
>  	case SNDRV_DMA_TYPE_DEV:
>  		snd_free_dev_pages(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
>  		break;
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index a68d4c6..74de2a3 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -3199,6 +3199,13 @@ 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 &&
> +			SNDRV_DMA_TYPE_DEV_IRAM != SNDRV_DMA_TYPE_DEV) {
> +		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)
> -- 
> 1.8.4
> 
>