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linux/sound/soc/soc-generic-dmaengine-pcm.c
Matthias Reichl 73fe01cfb3 ASoC: dmaengine_pcm: Add support for packed transfers 
dmaengine_pcm currently only supports setups where FIFO reads/writes
correspond to exactly one sample, eg 16-bit sample data is transferred
via 16-bit FIFO accesses, 32-bit data via 32-bit accesses.

This patch adds support for setups with fixed width FIFOs where
multiple samples are packed into a larger word.

For example setups with a 32-bit wide FIFO register that expect
16-bit sample transfers to be done with the left+right sample data
packed into a 32-bit word.

Support for packed transfers is controlled via the
SND_DMAENGINE_PCM_DAI_FLAG_PACK flag in snd_dmaengine_dai_dma_data.flags

If this flag is set dmaengine_pcm doesn't put any restriction on the
supported formats and sets the DMA transfer width to undefined.

This means control over the constraints is now transferred to the DAI
driver and it's responsible to provide proper configuration and
check for possible corner cases that aren't handled by the ALSA core.

Signed-off-by: Matthias Reichl <hias@horus.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-04-27 17:34:11 +01:00

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/*
* Copyright (C) 2013, 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.
*
*/
#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 <linux/dma-mapping.h>
#include <linux/of.h>
#include <sound/dmaengine_pcm.h>
/*
* The platforms dmaengine driver does not support reporting the amount of
* bytes that are still left to transfer.
*/
#define SND_DMAENGINE_PCM_FLAG_NO_RESIDUE BIT(31)
struct dmaengine_pcm {
struct dma_chan *chan[SNDRV_PCM_STREAM_LAST + 1];
const struct snd_dmaengine_pcm_config *config;
struct snd_soc_platform platform;
unsigned int flags;
};
static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p)
{
return container_of(p, struct dmaengine_pcm, platform);
}
static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
struct snd_pcm_substream *substream)
{
if (!pcm->chan[substream->stream])
return NULL;
return pcm->chan[substream->stream]->device->dev;
}
/**
* snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
* @substream: PCM substream
* @params: hw_params
* @slave_config: DMA slave config to prepare
*
* This function can be used as a generic prepare_slave_config callback for
* platforms which make use of the snd_dmaengine_dai_dma_data struct for their
* DAI DMA data. Internally the function will first call
* snd_hwparams_to_dma_slave_config to fill in the slave config based on the
* hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the
* remaining fields based on the DAI DMA data.
*/
int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct snd_dmaengine_dai_dma_data *dma_data;
int ret;
dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
if (ret)
return ret;
snd_dmaengine_pcm_set_config_from_dai_data(substream, dma_data,
slave_config);
return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_prepare_slave_config);
static int dmaengine_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
int (*prepare_slave_config)(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params,
struct dma_slave_config *slave_config);
struct dma_slave_config slave_config;
int ret;
memset(&slave_config, 0, sizeof(slave_config));
if (!pcm->config)
prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config;
else
prepare_slave_config = pcm->config->prepare_slave_config;
if (prepare_slave_config) {
ret = prepare_slave_config(substream, params, &slave_config);
if (ret)
return ret;
ret = dmaengine_slave_config(chan, &slave_config);
if (ret)
return ret;
}
return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
}
static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
struct device *dma_dev = dmaengine_dma_dev(pcm, substream);
struct dma_chan *chan = pcm->chan[substream->stream];
struct snd_dmaengine_dai_dma_data *dma_data;
struct dma_slave_caps dma_caps;
struct snd_pcm_hardware hw;
u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
int i, ret;
if (pcm->config && pcm->config->pcm_hardware)
return snd_soc_set_runtime_hwparams(substream,
pcm->config->pcm_hardware);
dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
memset(&hw, 0, sizeof(hw));
hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED;
hw.periods_min = 2;
hw.periods_max = UINT_MAX;
hw.period_bytes_min = 256;
hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
hw.buffer_bytes_max = SIZE_MAX;
hw.fifo_size = dma_data->fifo_size;
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
hw.info |= SNDRV_PCM_INFO_BATCH;
ret = dma_get_slave_caps(chan, &dma_caps);
if (ret == 0) {
if (dma_caps.cmd_pause)
hw.info |= SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME;
if (dma_caps.residue_granularity <= DMA_RESIDUE_GRANULARITY_SEGMENT)
hw.info |= SNDRV_PCM_INFO_BATCH;
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
addr_widths = dma_caps.dst_addr_widths;
else
addr_widths = dma_caps.src_addr_widths;
}
/*
* If SND_DMAENGINE_PCM_DAI_FLAG_PACK is set keep
* hw.formats set to 0, meaning no restrictions are in place.
* In this case it's the responsibility of the DAI driver to
* provide the supported format information.
*/
if (!(dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK))
/*
* Prepare formats mask for valid/allowed sample types. If the
* dma does not have support for the given physical word size,
* it needs to be masked out so user space can not use the
* format which produces corrupted audio.
* In case the dma driver does not implement the slave_caps the
* default assumption is that it supports 1, 2 and 4 bytes
* widths.
*/
for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
int bits = snd_pcm_format_physical_width(i);
/*
* Enable only samples with DMA supported physical
* widths
*/
switch (bits) {
case 8:
case 16:
case 24:
case 32:
case 64:
if (addr_widths & (1 << (bits / 8)))
hw.formats |= (1LL << i);
break;
default:
/* Unsupported types */
break;
}
}
return snd_soc_set_runtime_hwparams(substream, &hw);
}
static int dmaengine_pcm_open(struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
struct dma_chan *chan = pcm->chan[substream->stream];
int ret;
ret = dmaengine_pcm_set_runtime_hwparams(substream);
if (ret)
return ret;
return snd_dmaengine_pcm_open(substream, chan);
}
static struct dma_chan *dmaengine_pcm_compat_request_channel(
struct snd_soc_pcm_runtime *rtd,
struct snd_pcm_substream *substream)
{
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
struct snd_dmaengine_dai_dma_data *dma_data;
dma_filter_fn fn = NULL;
dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
return pcm->chan[0];
if (pcm->config && pcm->config->compat_request_channel)
return pcm->config->compat_request_channel(rtd, substream);
if (pcm->config)
fn = pcm->config->compat_filter_fn;
return snd_dmaengine_pcm_request_channel(fn, dma_data->filter_data);
}
static bool dmaengine_pcm_can_report_residue(struct device *dev,
struct dma_chan *chan)
{
struct dma_slave_caps dma_caps;
int ret;
ret = dma_get_slave_caps(chan, &dma_caps);
if (ret != 0) {
dev_warn(dev, "Failed to get DMA channel capabilities, falling back to period counting: %d\n",
ret);
return false;
}
if (dma_caps.residue_granularity == DMA_RESIDUE_GRANULARITY_DESCRIPTOR)
return false;
return true;
}
static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
const struct snd_dmaengine_pcm_config *config = pcm->config;
struct device *dev = rtd->platform->dev;
struct snd_dmaengine_dai_dma_data *dma_data;
struct snd_pcm_substream *substream;
size_t prealloc_buffer_size;
size_t max_buffer_size;
unsigned int i;
int ret;
if (config && config->prealloc_buffer_size) {
prealloc_buffer_size = config->prealloc_buffer_size;
max_buffer_size = config->pcm_hardware->buffer_bytes_max;
} else {
prealloc_buffer_size = 512 * 1024;
max_buffer_size = SIZE_MAX;
}
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
substream = rtd->pcm->streams[i].substream;
if (!substream)
continue;
dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
if (!pcm->chan[i] &&
(pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME))
pcm->chan[i] = dma_request_slave_channel(dev,
dma_data->chan_name);
if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
substream);
}
if (!pcm->chan[i]) {
dev_err(rtd->platform->dev,
"Missing dma channel for stream: %d\n", i);
return -EINVAL;
}
ret = snd_pcm_lib_preallocate_pages(substream,
SNDRV_DMA_TYPE_DEV_IRAM,
dmaengine_dma_dev(pcm, substream),
prealloc_buffer_size,
max_buffer_size);
if (ret)
return ret;
if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i]))
pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
}
return 0;
}
static snd_pcm_uframes_t dmaengine_pcm_pointer(
struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
return snd_dmaengine_pcm_pointer_no_residue(substream);
else
return snd_dmaengine_pcm_pointer(substream);
}
static const struct snd_pcm_ops dmaengine_pcm_ops = {
.open = dmaengine_pcm_open,
.close = snd_dmaengine_pcm_close,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = dmaengine_pcm_hw_params,
.hw_free = snd_pcm_lib_free_pages,
.trigger = snd_dmaengine_pcm_trigger,
.pointer = dmaengine_pcm_pointer,
};
static const struct snd_soc_platform_driver dmaengine_pcm_platform = {
.component_driver = {
.probe_order = SND_SOC_COMP_ORDER_LATE,
},
.ops = &dmaengine_pcm_ops,
.pcm_new = dmaengine_pcm_new,
};
static const char * const dmaengine_pcm_dma_channel_names[] = {
[SNDRV_PCM_STREAM_PLAYBACK] = "tx",
[SNDRV_PCM_STREAM_CAPTURE] = "rx",
};
static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
struct device *dev, const struct snd_dmaengine_pcm_config *config)
{
unsigned int i;
const char *name;
struct dma_chan *chan;
if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT |
SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) ||
!dev->of_node)
return 0;
if (config && config->dma_dev) {
/*
* If this warning is seen, it probably means that your Linux
* device structure does not match your HW device structure.
* It would be best to refactor the Linux device structure to
* correctly match the HW structure.
*/
dev_warn(dev, "DMA channels sourced from device %s",
dev_name(config->dma_dev));
dev = config->dma_dev;
}
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
i++) {
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
name = "rx-tx";
else
name = dmaengine_pcm_dma_channel_names[i];
if (config && config->chan_names[i])
name = config->chan_names[i];
chan = dma_request_slave_channel_reason(dev, name);
if (IS_ERR(chan)) {
if (PTR_ERR(chan) == -EPROBE_DEFER)
return -EPROBE_DEFER;
pcm->chan[i] = NULL;
} else {
pcm->chan[i] = chan;
}
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
break;
}
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
pcm->chan[1] = pcm->chan[0];
return 0;
}
static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm)
{
unsigned int i;
for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
i++) {
if (!pcm->chan[i])
continue;
dma_release_channel(pcm->chan[i]);
if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
break;
}
}
/**
* snd_dmaengine_pcm_register - Register a dmaengine based PCM device
* @dev: The parent device for the PCM device
* @config: Platform specific PCM configuration
* @flags: Platform specific quirks
*/
int snd_dmaengine_pcm_register(struct device *dev,
const struct snd_dmaengine_pcm_config *config, unsigned int flags)
{
struct dmaengine_pcm *pcm;
int ret;
pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
if (!pcm)
return -ENOMEM;
pcm->config = config;
pcm->flags = flags;
ret = dmaengine_pcm_request_chan_of(pcm, dev, config);
if (ret)
goto err_free_dma;
ret = snd_soc_add_platform(dev, &pcm->platform,
&dmaengine_pcm_platform);
if (ret)
goto err_free_dma;
return 0;
err_free_dma:
dmaengine_pcm_release_chan(pcm);
kfree(pcm);
return ret;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);
/**
* snd_dmaengine_pcm_unregister - Removes a dmaengine based PCM device
* @dev: Parent device the PCM was register with
*
* Removes a dmaengine based PCM device previously registered with
* snd_dmaengine_pcm_register.
*/
void snd_dmaengine_pcm_unregister(struct device *dev)
{
struct snd_soc_platform *platform;
struct dmaengine_pcm *pcm;
platform = snd_soc_lookup_platform(dev);
if (!platform)
return;
pcm = soc_platform_to_pcm(platform);
snd_soc_remove_platform(platform);
dmaengine_pcm_release_chan(pcm);
kfree(pcm);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);
MODULE_LICENSE("GPL");
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