Re: [PATCH v7] ALSA: Add SoC on-chip internal ram support for DMA buffer allocation

[Nicolin Chen <b42378@freescale.com>]

On Thu, Oct 24, 2013 at 09:22:49AM +0200, Takashi Iwai wrote:
> At Wed, 23 Oct 2013 11:47:43 +0800,
> Nicolin Chen wrote:
> > 
> > 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>
> 
> Thanks, now applied with ack by Lars.
> 
> 
> Takashi

Thank you. And Iwai-san, could you please tell me in which repo and branch
could I cherry-pick this patch?

I tried some in git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git
but failed to locate the patch.

Thank you,
Nicolin Chen

> 
> > ---
> > Changelog
> > v6->v7:
> >  * Assigned pool to private_data field and accordingly refined helper functions.
> > v5->v6:
> >  * Dropped remaining OF dependency bacause no need to add them:
> >    of_node doesn't care about OF; of_get_named_gen_pool() returns NULL if !OF.
> > v4->v5:
> >  * Minimized the OF dependency.
> > v3->v4:
> >  * Appropriately placed '#ifdef CONFIG_OF'
> >  * Tested by adding '#undef CONFIG_OF' to modified files, and passed compiling.
> > 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 |  1 +
> >  sound/core/memalloc.c    | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  sound/core/pcm_native.c  |  6 ++++++
> >  3 files changed, 59 insertions(+)
> > 
> > diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
> > index cf15b82..510aec4 100644
> > --- a/include/sound/memalloc.h
> > +++ b/include/sound/memalloc.h
> > @@ -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
> > diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
> > index bdf826f..18c1d47 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 +158,46 @@ 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;
> > diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> > index a68d4c6..513f095 100644
> > --- a/sound/core/pcm_native.c
> > +++ b/sound/core/pcm_native.c
> > @@ -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)
> > -- 
> > 1.8.4
> > 
> > 
>