Re: [alsa-devel] [RFC 4/7] ASoC: Add dmaengine PCM helper functions

On Wed, Feb 22, 2012 at 10:49:08AM +0100, Lars-Peter Clausen wrote:

This patch adds a set of functions which are intended to be used when implementing a dmaengine based sound PCM driver.

Adding Morimoto-san as he has just implemented dmaengine support for fsi which should also be able to use the same framework. Not cutting any of the text so he can see it.

Signed-off-by: Lars-Peter Clausen lars@metafoo.de Tested-by: Shawn Guo shawn.guo@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@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@metafoo.de
• • Based on:
• • imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer s.hauer@pengutronix.de
• • mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
• • ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek buytenh@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