ASoC: Add support for SPEAr ASoC pcm layer.

This patch add support for the SPEAr ASoC pcm layer in ASoC
framework. The pcm layer uses common snd_dmaengine framework.
Signed-off-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

include/sound/spear_dma.h

+/*
+* linux/spear_dma.h
+*
+* Copyright (ST) 2012 Rajeev Kumar (rajeev-dlh.kumar@st.com)
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation; either version 2 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*
+*/
+
+#ifndef SPEAR_DMA_H
+#define SPEAR_DMA_H
+
+#include <linux/dmaengine.h>
+
+struct spear_dma_data {
+	void *data;
+	dma_addr_t addr;
+	u32 max_burst;
+	enum dma_slave_buswidth addr_width;
+	bool (*filter)(struct dma_chan *chan, void *slave);
+};
+
+#endif /* SPEAR_DMA_H */

sound/soc/spear/spear_pcm.c

+/*
+ * ALSA PCM interface for ST SPEAr Processors
+ *
+ * sound/soc/spear/spear_pcm.c
+ *
+ * Copyright (C) 2012 ST Microelectronics
+ * Rajeev Kumar<rajeev-dlh.kumar@st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/spear_dma.h>
+
+struct snd_pcm_hardware spear_pcm_hardware = {
+	.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
+		 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
+	.buffer_bytes_max = 16 * 1024, /* max buffer size */
+	.period_bytes_min = 2 * 1024, /* 1 msec data minimum period size */
+	.period_bytes_max = 2 * 1024, /* maximum period size */
+	.periods_min = 1, /* min # periods */
+	.periods_max = 8, /* max # of periods */
+	.fifo_size = 0, /* fifo size in bytes */
+};
+
+static int spear_pcm_hw_params(struct snd_pcm_substream *substream,
+		struct snd_pcm_hw_params *params)
+{
+	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+
+	return 0;
+}
+
+static int spear_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	snd_pcm_set_runtime_buffer(substream, NULL);
+
+	return 0;
+}
+
+static int spear_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+
+	struct spear_dma_data *dma_data = (struct spear_dma_data *)
+		snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+	int ret;
+
+	ret = snd_soc_set_runtime_hwparams(substream, &spear_pcm_hardware);
+	if (ret)
+		return ret;
+
+	ret = snd_dmaengine_pcm_open(substream, dma_data->filter, dma_data);
+	if (ret)
+		return ret;
+
+	snd_dmaengine_pcm_set_data(substream, dma_data);
+
+	return 0;
+}
+
+static int spear_pcm_close(struct snd_pcm_substream *substream)
+{
+
+	snd_dmaengine_pcm_close(substream);
+
+	return 0;
+}
+
+static int spear_pcm_mmap(struct snd_pcm_substream *substream,
+		struct vm_area_struct *vma)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
+			runtime->dma_area, runtime->dma_addr,
+			runtime->dma_bytes);
+}
+
+static struct snd_pcm_ops spear_pcm_ops = {
+	.open		= spear_pcm_open,
+	.close		= spear_pcm_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= spear_pcm_hw_params,
+	.hw_free	= spear_pcm_hw_free,
+	.trigger	= snd_dmaengine_pcm_trigger,
+	.pointer	= snd_dmaengine_pcm_pointer,
+	.mmap		= spear_pcm_mmap,
+};
+
+static int
+spear_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream,
+		size_t size)
+{
+	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
+	struct snd_dma_buffer *buf = &substream->dma_buffer;
+
+	buf->dev.type = SNDRV_DMA_TYPE_DEV;
+	buf->dev.dev = pcm->card->dev;
+	buf->private_data = NULL;
+
+	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
+			&buf->addr, GFP_KERNEL);
+	if (!buf->area)
+		return -ENOMEM;
+
+	dev_info(buf->dev.dev,
+			" preallocate_dma_buffer: area=%p, addr=%p, size=%d\n",
+			(void *)buf->area, (void *)buf->addr, size);
+
+	buf->bytes = size;
+	return 0;
+}
+
+static void spear_pcm_free(struct snd_pcm *pcm)
+{
+	struct snd_pcm_substream *substream;
+	struct snd_dma_buffer *buf;
+	int stream;
+
+	for (stream = 0; stream < 2; stream++) {
+		substream = pcm->streams[stream].substream;
+		if (!substream)
+			continue;
+
+		buf = &substream->dma_buffer;
+		if (!buf && !buf->area)
+			continue;
+
+		dma_free_writecombine(pcm->card->dev, buf->bytes,
+				buf->area, buf->addr);
+		buf->area = NULL;
+	}
+}
+
+static u64 spear_pcm_dmamask = DMA_BIT_MASK(32);
+
+static int spear_pcm_new(struct snd_card *card,
+		struct snd_soc_dai *dai, struct snd_pcm *pcm)
+{
+	int ret;
+
+	if (!card->dev->dma_mask)
+		card->dev->dma_mask = &spear_pcm_dmamask;
+	if (!card->dev->coherent_dma_mask)
+		card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
+
+	if (dai->driver->playback.channels_min) {
+		ret = spear_pcm_preallocate_dma_buffer(pcm,
+				SNDRV_PCM_STREAM_PLAYBACK,
+				spear_pcm_hardware.buffer_bytes_max);
+		if (ret)
+			return ret;
+	}
+
+	if (dai->driver->capture.channels_min) {
+		ret = spear_pcm_preallocate_dma_buffer(pcm,
+				SNDRV_PCM_STREAM_CAPTURE,
+				spear_pcm_hardware.buffer_bytes_max);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+struct snd_soc_platform_driver spear_soc_platform = {
+	.ops		=	&spear_pcm_ops,
+	.pcm_new	=	spear_pcm_new,
+	.pcm_free	=	spear_pcm_free,
+};
+
+static int __devinit spear_soc_platform_probe(struct platform_device *pdev)
+{
+	return snd_soc_register_platform(&pdev->dev, &spear_soc_platform);
+}
+
+static int __devexit spear_soc_platform_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_platform(&pdev->dev);
+
+	return 0;
+}
+
+static struct platform_driver spear_pcm_driver = {
+	.driver = {
+		.name = "spear-pcm-audio",
+		.owner = THIS_MODULE,
+	},
+
+	.probe = spear_soc_platform_probe,
+	.remove = __devexit_p(spear_soc_platform_remove),
+};
+
+module_platform_driver(spear_pcm_driver);
+
+MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
+MODULE_DESCRIPTION("SPEAr PCM DMA module");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:spear-pcm-audio");