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

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@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