[ALSA] ARM DMA subsystem

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>

sound/arm/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, 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);
+}

sound/arm/devdma.h

+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);