linux/sound/soc/atmel/atmel-pcm-dma.c
Lars-Peter Clausen acde50a7bf ASoC: dmaengine_pcm: Make FLAG_NO_RESIDUE internal
Whether residue can be reported or not is not a property of the audio
controller but of the DMA controller. The FLAG_NO_RESIDUE was initially
added when the DMAengine framework had no support for describing the residue
reporting capabilities of the controller. Support for this was added quite a
while ago and recently the DMAengine framework started to complain if a
driver does not describe its capabilities and a lot of patches have been
merged that add support for this where it was missing. So it should be safe
to assume that driver on actively used platforms properly implement the DMA
capabilities API.

This patch makes the FLAG_NO_RESIDUE internal and no longer allows audio
controller drivers to manually set the flag. If a DMA driver against
expectations does not support reporting its capabilities for now the generic
DMAengine PCM driver will now emit a warning and simply assume that residue
reporting is not supported. In the future this might be changed to aborting
with an error.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-04-27 19:26:07 +01:00

140 lines
4.3 KiB
C

/*
* atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.
*
* Copyright (C) 2012 Atmel
*
* Author: Bo Shen <voice.shen@atmel.com>
*
* Based on atmel-pcm by:
* Sedji Gaouaou <sedji.gaouaou@atmel.com>
* Copyright 2008 Atmel
*
* 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
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/atmel-ssc.h>
#include <linux/platform_data/dma-atmel.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/dmaengine_pcm.h>
#include "atmel-pcm.h"
/*--------------------------------------------------------------------------*\
* Hardware definition
\*--------------------------------------------------------------------------*/
static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
.info = SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_RESUME |
SNDRV_PCM_INFO_PAUSE,
.period_bytes_min = 256, /* lighting DMA overhead */
.period_bytes_max = 2 * 0xffff, /* if 2 bytes format */
.periods_min = 8,
.periods_max = 1024, /* no limit */
.buffer_bytes_max = 512 * 1024,
};
/**
* atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
*
* We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
* check if any overrun occured.
*/
static void atmel_pcm_dma_irq(u32 ssc_sr,
struct snd_pcm_substream *substream)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
struct atmel_pcm_dma_params *prtd;
prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
if (ssc_sr & prtd->mask->ssc_error) {
if (snd_pcm_running(substream))
pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
substream->stream == SNDRV_PCM_STREAM_PLAYBACK
? "underrun" : "overrun", prtd->name,
ssc_sr);
/* stop RX and capture: will be enabled again at restart */
ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
snd_pcm_stop_xrun(substream);
/* now drain RHR and read status to remove xrun condition */
ssc_readx(prtd->ssc->regs, SSC_RHR);
ssc_readx(prtd->ssc->regs, SSC_SR);
}
}
static int atmel_pcm_configure_dma(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 atmel_pcm_dma_params *prtd;
struct ssc_device *ssc;
int ret;
prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
ssc = prtd->ssc;
ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
if (ret) {
pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
return ret;
}
slave_config->dst_addr = ssc->phybase + SSC_THR;
slave_config->dst_maxburst = 1;
slave_config->src_addr = ssc->phybase + SSC_RHR;
slave_config->src_maxburst = 1;
prtd->dma_intr_handler = atmel_pcm_dma_irq;
return 0;
}
static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
.prepare_slave_config = atmel_pcm_configure_dma,
.pcm_hardware = &atmel_pcm_dma_hardware,
.prealloc_buffer_size = 64 * 1024,
};
int atmel_pcm_dma_platform_register(struct device *dev)
{
return snd_dmaengine_pcm_register(dev, &atmel_dmaengine_pcm_config, 0);
}
EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
void atmel_pcm_dma_platform_unregister(struct device *dev)
{
snd_dmaengine_pcm_unregister(dev);
}
EXPORT_SYMBOL(atmel_pcm_dma_platform_unregister);
MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
MODULE_DESCRIPTION("Atmel DMA based PCM module");
MODULE_LICENSE("GPL");