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>

diff --git a/include/sound/memalloc.h b/include/sound/memalloc.h
index cf15b82..510aec4 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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)