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[ALSA] ARM DMA subsystem

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ARM DMA routines
The patch below adds a convenient re-usable shim around the extended
ARM DMA API, and is used by several ARM ALSA drivers.

Signed-off-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Russell King 2005-05-12 10:25:58 +02:00 committed by Jaroslav Kysela
parent f7de9cfd25
commit 9b9a5afffd
2 changed files with 84 additions and 0 deletions
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81
sound/arm/devdma.c Normal file
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/*
* linux/sound/arm/devdma.c
*
* Copyright (C) 2003-2004 Russell King, All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* ARM DMA shim for ALSA.
*/
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <sound/driver.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include "devdma.h"
void devdma_hw_free(struct device *dev, snd_pcm_substream_t *substream)
{
snd_pcm_runtime_t *runtime = substream->runtime;
struct snd_dma_buffer *buf = runtime->dma_buffer_p;
if (runtime->dma_area == NULL)
return;
if (buf != &substream->dma_buffer) {
dma_free_coherent(buf->dev.dev, buf->bytes, buf->area, buf->addr);
kfree(runtime->dma_buffer_p);
}
snd_pcm_set_runtime_buffer(substream, NULL);
}
int devdma_hw_alloc(struct device *dev, snd_pcm_substream_t *substream, size_t size)
{
snd_pcm_runtime_t *runtime = substream->runtime;
struct snd_dma_buffer *buf = runtime->dma_buffer_p;
int ret = 0;
if (buf) {
if (buf->bytes >= size)
goto out;
devdma_hw_free(dev, substream);
}
if (substream->dma_buffer.area != NULL && substream->dma_buffer.bytes >= size) {
buf = &substream->dma_buffer;
} else {
buf = kmalloc(sizeof(struct snd_dma_buffer), GFP_KERNEL);
if (!buf)
goto nomem;
buf->dev.type = SNDRV_DMA_TYPE_DEV;
buf->dev.dev = dev;
buf->area = dma_alloc_coherent(dev, size, &buf->addr, GFP_KERNEL);
buf->bytes = size;
buf->private_data = NULL;
if (!buf->area)
goto free;
}
snd_pcm_set_runtime_buffer(substream, buf);
ret = 1;
out:
runtime->dma_bytes = size;
return ret;
free:
kfree(buf);
nomem:
return -ENOMEM;
}
int devdma_mmap(struct device *dev, snd_pcm_substream_t *substream, struct vm_area_struct *vma)
{
snd_pcm_runtime_t *runtime = substream->runtime;
return dma_mmap_coherent(dev, vma, runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);
}

3
sound/arm/devdma.h Normal file
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void devdma_hw_free(struct device *dev, snd_pcm_substream_t *substream);
int devdma_hw_alloc(struct device *dev, snd_pcm_substream_t *substream, size_t size);
int devdma_mmap(struct device *dev, snd_pcm_substream_t *substream, struct vm_area_struct *vma);