[alsa-devel] [RFC 4/7] ASoC: Add dmaengine PCM helper functions
Lars-Peter Clausen
lars at metafoo.de
Wed Feb 22 10:49:08 CET 2012
This patch adds a set of functions which are intended to be used when
implementing a dmaengine based sound PCM driver.
Signed-off-by: Lars-Peter Clausen <lars at metafoo.de>
Tested-by: Shawn Guo <shawn.guo at linaro.org>
---
include/sound/dmaengine_pcm.h | 49 +++++++
sound/soc/Kconfig | 3 +
sound/soc/Makefile | 3 +
sound/soc/soc-dmaengine-pcm.c | 287 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 342 insertions(+), 0 deletions(-)
create mode 100644 include/sound/dmaengine_pcm.h
create mode 100644 sound/soc/soc-dmaengine-pcm.c
diff --git a/include/sound/dmaengine_pcm.h b/include/sound/dmaengine_pcm.h
new file mode 100644
index 0000000..a8fcaa6
--- /dev/null
+++ b/include/sound/dmaengine_pcm.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2012, Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars at metafoo.de>
+ *
+ * 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.
+ *
+ * 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+#ifndef __SOUND_DMAENGINE_PCM_H__
+#define __SOUND_DMAENGINE_PCM_H__
+
+#include <sound/pcm.h>
+#include <linux/dmaengine.h>
+
+/**
+ * snd_pcm_substream_to_dma_direction - Get dma_transfer_direction for a PCM
+ * substream
+ * @substream: PCM substream
+ */
+static inline enum dma_transfer_direction
+snd_pcm_substream_to_dma_direction(const struct snd_pcm_substream *substream)
+{
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+ return DMA_MEM_TO_DEV;
+ else
+ return DMA_DEV_TO_MEM;
+}
+
+void snd_dmaengine_pcm_set_data(struct snd_pcm_substream *substream, void *data);
+void *snd_dmaengine_pcm_get_data(struct snd_pcm_substream *substream);
+
+int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
+ const struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config);
+int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd);
+snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream);
+
+int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
+ dma_filter_fn filter_fn, void *filter_data);
+int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream);
+
+struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
+
+#endif
diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 35e662d..91c9855 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -25,6 +25,9 @@ if SND_SOC
config SND_SOC_AC97_BUS
bool
+config SND_SOC_DMAENGINE_PCM
+ bool
+
# All the supported SoCs
source "sound/soc/atmel/Kconfig"
source "sound/soc/au1x/Kconfig"
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index 9ea8ac8..2feaf37 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -1,6 +1,9 @@
snd-soc-core-objs := soc-core.o soc-dapm.o soc-jack.o soc-cache.o soc-utils.o
snd-soc-core-objs += soc-pcm.o soc-io.o
+snd-soc-dmaengine-pcm-objs := soc-dmaengine-pcm.o
+obj-$(CONFIG_SND_SOC_DMAENGINE_PCM) += snd-soc-dmaengine-pcm.o
+
obj-$(CONFIG_SND_SOC) += snd-soc-core.o
obj-$(CONFIG_SND_SOC) += codecs/
obj-$(CONFIG_SND_SOC) += atmel/
diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
new file mode 100644
index 0000000..0526cf8
--- /dev/null
+++ b/sound/soc/soc-dmaengine-pcm.c
@@ -0,0 +1,287 @@
+/*
+ * Copyright (C) 2012, Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars at metafoo.de>
+ *
+ * Based on:
+ * imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer at pengutronix.de>
+ * mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
+ * ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh at wantstofly.org>
+ * Copyright (C) 2006 Applied Data Systems
+ *
+ * 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.
+ *
+ * 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/dmaengine.h>
+#include <linux/slab.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#include <sound/dmaengine_pcm.h>
+
+struct dmaengine_pcm_runtime_data {
+ struct dma_chan *dma_chan;
+
+ unsigned int pos;
+
+ void *data;
+};
+
+static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
+ const struct snd_pcm_substream *substream)
+{
+ return substream->runtime->private_data;
+}
+
+/**
+ * snd_dmaengine_pcm_set_data - Set dmaengine substream private data
+ * @substream: PCM substream
+ * @data: Data to set
+ */
+void snd_dmaengine_pcm_set_data(struct snd_pcm_substream *substream, void *data)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+ prtd->data = data;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_data);
+
+/**
+ * snd_dmaengine_pcm_get_data - Get dmaeinge substream private data
+ * @substream: PCM substream
+ *
+ * Returns the data previously set with snd_dmaengine_pcm_set_data
+ */
+void *snd_dmaengine_pcm_get_data(struct snd_pcm_substream *substream)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+ return prtd->data;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_data);
+
+struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+ return prtd->dma_chan;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);
+
+/**
+ * snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
+ * @substream: PCM substream
+ * @params: hw_params
+ * @slave_config: DMA slave config
+ *
+ * This function can be used to initialize a dma_slave_config from a substream
+ * and hw_params in a dmaengine based PCM driver implementation.
+ */
+int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
+ const struct snd_pcm_hw_params *params,
+ struct dma_slave_config *slave_config)
+{
+ enum dma_slave_buswidth buswidth;
+
+ switch (params_format(params)) {
+ case SNDRV_PCM_FORMAT_S8:
+ buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ break;
+ case SNDRV_PCM_FORMAT_S16_LE:
+ buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
+ break;
+ case SNDRV_PCM_FORMAT_S18_3LE:
+ case SNDRV_PCM_FORMAT_S20_3LE:
+ case SNDRV_PCM_FORMAT_S24_LE:
+ case SNDRV_PCM_FORMAT_S32_LE:
+ buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+ slave_config->direction = DMA_MEM_TO_DEV;
+ slave_config->dst_addr_width = buswidth;
+ } else {
+ slave_config->direction = DMA_DEV_TO_MEM;
+ slave_config->src_addr_width = buswidth;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
+
+static void dmaengine_pcm_dma_complete(void *arg)
+{
+ struct snd_pcm_substream *substream = arg;
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+ prtd->pos += snd_pcm_lib_period_bytes(substream);
+ if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
+ prtd->pos = 0;
+
+ snd_pcm_period_elapsed(substream);
+}
+
+static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ struct dma_chan *chan = prtd->dma_chan;
+ struct dma_async_tx_descriptor *desc;
+ enum dma_transfer_direction direction;
+
+ direction = snd_pcm_substream_to_dma_direction(substream);
+
+ desc = chan->device->device_prep_dma_cyclic(chan,
+ substream->runtime->dma_addr,
+ snd_pcm_lib_buffer_bytes(substream),
+ snd_pcm_lib_period_bytes(substream), direction);
+
+ if (!desc)
+ return -ENOMEM;
+
+ desc->callback = dmaengine_pcm_dma_complete;
+ desc->callback_param = substream;
+ dmaengine_submit(desc);
+
+ return 0;
+}
+
+/**
+ * snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
+ * @substream: PCM substream
+ * @cmd: Trigger command
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ *
+ * This function can be used as the PCM trigger callback for dmaengine based PCM
+ * driver implementations.
+ */
+int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ int ret;
+
+ switch (cmd) {
+ case SNDRV_PCM_TRIGGER_START:
+ ret = dmaengine_pcm_prepare_and_submit(substream);
+ if (ret)
+ return ret;
+ dma_async_issue_pending(prtd->dma_chan);
+ break;
+ case SNDRV_PCM_TRIGGER_RESUME:
+ case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+ dmaengine_resume(prtd->dma_chan);
+ break;
+ case SNDRV_PCM_TRIGGER_SUSPEND:
+ case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+ dmaengine_pause(prtd->dma_chan);
+ break;
+ case SNDRV_PCM_TRIGGER_STOP:
+ dmaengine_terminate_all(prtd->dma_chan);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
+
+/**
+ * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
+ * @substream: PCM substream
+ *
+ * This function can be used as the PCM pointer callback for dmaengine based PCM
+ * driver implementations.
+ */
+snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+ return bytes_to_frames(substream->runtime, prtd->pos);
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
+
+static int dmaengine_pcm_request_channel(struct dmaengine_pcm_runtime_data *prtd,
+ dma_filter_fn filter_fn, void *filter_data)
+{
+ dma_cap_mask_t mask;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ dma_cap_set(DMA_CYCLIC, mask);
+ prtd->dma_chan = dma_request_channel(mask, filter_fn, filter_data);
+
+ if (!prtd->dma_chan)
+ return -ENXIO;
+
+ return 0;
+}
+
+/**
+ * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
+ * @substream: PCM substream
+ * @filter_fn: Filter function used to request the DMA channel
+ * @filter_data: Data passed to the DMA filter function
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ *
+ * This function will request a DMA channel using the passed filter function and
+ * data. The function should usually be called from the pcm open callback.
+ *
+ * Note that this function will use private_data field of the substream's
+ * runtime. So it is not availabe to your pcm driver implementation. If you need
+ * to keep additional data attached to a substream use
+ * snd_dmaeinge_pcm_{set,get}_data.
+ */
+int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
+ dma_filter_fn filter_fn, void *filter_data)
+{
+ struct dmaengine_pcm_runtime_data *prtd;
+ int ret;
+
+ ret = snd_pcm_hw_constraint_integer(substream->runtime,
+ SNDRV_PCM_HW_PARAM_PERIODS);
+ if (ret < 0)
+ return ret;
+
+ prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
+ if (!prtd)
+ return -ENOMEM;
+
+ ret = dmaengine_pcm_request_channel(prtd, filter_fn, filter_data);
+ if (ret < 0) {
+ kfree(prtd);
+ return ret;
+ }
+
+ substream->runtime->private_data = prtd;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
+
+/**
+ * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
+ * @substream: PCM substream
+ */
+int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
+{
+ struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+
+ dma_release_channel(prtd->dma_chan);
+ kfree(prtd);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
--
1.7.9
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