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devdma.c

/*
 *  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, struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *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, struct snd_pcm_substream *substream, size_t size)
{
      struct snd_pcm_runtime *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, struct snd_pcm_substream *substream, struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      return dma_mmap_coherent(dev, vma, runtime->dma_area, runtime->dma_addr, runtime->dma_bytes);
}

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