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linux-stable/sound/soc/atmel/atmel-pcm-pdc.c
Lars-Peter Clausen 22eee4d3ef
ASoC: atmel-pdc: Use managed DMA buffer allocation 
Instead of manually managing its DMA buffers using
dma_{alloc,free}_coherent() lets the sound core take care of this using
managed buffers.

On one hand this reduces the amount of boiler plate code, but the main
motivation for the change is to use the shared code where possible. This
makes it easier to argue about correctness and that the code does not
contain subtle bugs like data leakage or similar.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20210106133650.13509-1-lars@metafoo.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-01-13 11:36:15 +00:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* atmel-pcm.c -- ALSA PCM interface for the Atmel atmel SoC.
*
* Copyright (C) 2005 SAN People
* Copyright (C) 2008 Atmel
*
* Authors: Sedji Gaouaou <sedji.gaouaou@atmel.com>
*
* Based on at91-pcm. by:
* Frank Mandarino <fmandarino@endrelia.com>
* Copyright 2006 Endrelia Technologies Inc.
*
* Based on pxa2xx-pcm.c by:
*
* Author: Nicolas Pitre
* Created: Nov 30, 2004
* Copyright: (C) 2004 MontaVista Software, Inc.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel-ssc.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include "atmel-pcm.h"
static int atmel_pcm_new(struct snd_soc_component *component,
struct snd_soc_pcm_runtime *rtd)
{
struct snd_card *card = rtd->card->snd_card;
int ret;
ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
if (ret)
return ret;
snd_pcm_set_managed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
card->dev, ATMEL_SSC_DMABUF_SIZE,
ATMEL_SSC_DMABUF_SIZE);
return 0;
}
/*--------------------------------------------------------------------------*\
* Hardware definition
\*--------------------------------------------------------------------------*/
/* TODO: These values were taken from the AT91 platform driver, check
* them against real values for AT32
*/
static const struct snd_pcm_hardware atmel_pcm_hardware = {
.info = SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID |
SNDRV_PCM_INFO_INTERLEAVED |
SNDRV_PCM_INFO_PAUSE,
.period_bytes_min = 32,
.period_bytes_max = 8192,
.periods_min = 2,
.periods_max = 1024,
.buffer_bytes_max = ATMEL_SSC_DMABUF_SIZE,
};
/*--------------------------------------------------------------------------*\
* Data types
\*--------------------------------------------------------------------------*/
struct atmel_runtime_data {
struct atmel_pcm_dma_params *params;
dma_addr_t dma_buffer; /* physical address of dma buffer */
dma_addr_t dma_buffer_end; /* first address beyond DMA buffer */
size_t period_size;
dma_addr_t period_ptr; /* physical address of next period */
};
/*--------------------------------------------------------------------------*\
* ISR
\*--------------------------------------------------------------------------*/
static void atmel_pcm_dma_irq(u32 ssc_sr,
struct snd_pcm_substream *substream)
{
struct atmel_runtime_data *prtd = substream->runtime->private_data;
struct atmel_pcm_dma_params *params = prtd->params;
static int count;
count++;
if (ssc_sr & params->mask->ssc_endbuf) {
pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x, count=%d)\n",
substream->stream == SNDRV_PCM_STREAM_PLAYBACK
? "underrun" : "overrun",
params->name, ssc_sr, count);
/* re-start the PDC */
ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
params->mask->pdc_disable);
prtd->period_ptr += prtd->period_size;
if (prtd->period_ptr >= prtd->dma_buffer_end)
prtd->period_ptr = prtd->dma_buffer;
ssc_writex(params->ssc->regs, params->pdc->xpr,
prtd->period_ptr);
ssc_writex(params->ssc->regs, params->pdc->xcr,
prtd->period_size / params->pdc_xfer_size);
ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
params->mask->pdc_enable);
}
if (ssc_sr & params->mask->ssc_endx) {
/* Load the PDC next pointer and counter registers */
prtd->period_ptr += prtd->period_size;
if (prtd->period_ptr >= prtd->dma_buffer_end)
prtd->period_ptr = prtd->dma_buffer;
ssc_writex(params->ssc->regs, params->pdc->xnpr,
prtd->period_ptr);
ssc_writex(params->ssc->regs, params->pdc->xncr,
prtd->period_size / params->pdc_xfer_size);
}
snd_pcm_period_elapsed(substream);
}
/*--------------------------------------------------------------------------*\
* PCM operations
\*--------------------------------------------------------------------------*/
static int atmel_pcm_hw_params(struct snd_soc_component *component,
struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct atmel_runtime_data *prtd = runtime->private_data;
struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
/* this may get called several times by oss emulation
* with different params */
prtd->params = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
prtd->params->dma_intr_handler = atmel_pcm_dma_irq;
prtd->dma_buffer = runtime->dma_addr;
prtd->dma_buffer_end = runtime->dma_addr + runtime->dma_bytes;
prtd->period_size = params_period_bytes(params);
pr_debug("atmel-pcm: "
"hw_params: DMA for %s initialized "
"(dma_bytes=%zu, period_size=%zu)\n",
prtd->params->name,
runtime->dma_bytes,
prtd->period_size);
return 0;
}
static int atmel_pcm_hw_free(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct atmel_runtime_data *prtd = substream->runtime->private_data;
struct atmel_pcm_dma_params *params = prtd->params;
if (params != NULL) {
ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
params->mask->pdc_disable);
prtd->params->dma_intr_handler = NULL;
}
return 0;
}
static int atmel_pcm_prepare(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct atmel_runtime_data *prtd = substream->runtime->private_data;
struct atmel_pcm_dma_params *params = prtd->params;
ssc_writex(params->ssc->regs, SSC_IDR,
params->mask->ssc_endx | params->mask->ssc_endbuf);
ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
params->mask->pdc_disable);
return 0;
}
static int atmel_pcm_trigger(struct snd_soc_component *component,
struct snd_pcm_substream *substream, int cmd)
{
struct snd_pcm_runtime *rtd = substream->runtime;
struct atmel_runtime_data *prtd = rtd->private_data;
struct atmel_pcm_dma_params *params = prtd->params;
int ret = 0;
pr_debug("atmel-pcm:buffer_size = %ld,"
"dma_area = %p, dma_bytes = %zu\n",
rtd->buffer_size, rtd->dma_area, rtd->dma_bytes);
switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
prtd->period_ptr = prtd->dma_buffer;
ssc_writex(params->ssc->regs, params->pdc->xpr,
prtd->period_ptr);
ssc_writex(params->ssc->regs, params->pdc->xcr,
prtd->period_size / params->pdc_xfer_size);
prtd->period_ptr += prtd->period_size;
ssc_writex(params->ssc->regs, params->pdc->xnpr,
prtd->period_ptr);
ssc_writex(params->ssc->regs, params->pdc->xncr,
prtd->period_size / params->pdc_xfer_size);
pr_debug("atmel-pcm: trigger: "
"period_ptr=%lx, xpr=%u, "
"xcr=%u, xnpr=%u, xncr=%u\n",
(unsigned long)prtd->period_ptr,
ssc_readx(params->ssc->regs, params->pdc->xpr),
ssc_readx(params->ssc->regs, params->pdc->xcr),
ssc_readx(params->ssc->regs, params->pdc->xnpr),
ssc_readx(params->ssc->regs, params->pdc->xncr));
ssc_writex(params->ssc->regs, SSC_IER,
params->mask->ssc_endx | params->mask->ssc_endbuf);
ssc_writex(params->ssc->regs, SSC_PDC_PTCR,
params->mask->pdc_enable);
pr_debug("sr=%u imr=%u\n",
ssc_readx(params->ssc->regs, SSC_SR),
ssc_readx(params->ssc->regs, SSC_IER));
break; /* SNDRV_PCM_TRIGGER_START */
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
params->mask->pdc_disable);
break;
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
ssc_writex(params->ssc->regs, ATMEL_PDC_PTCR,
params->mask->pdc_enable);
break;
default:
ret = -EINVAL;
}
return ret;
}
static snd_pcm_uframes_t atmel_pcm_pointer(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct atmel_runtime_data *prtd = runtime->private_data;
struct atmel_pcm_dma_params *params = prtd->params;
dma_addr_t ptr;
snd_pcm_uframes_t x;
ptr = (dma_addr_t) ssc_readx(params->ssc->regs, params->pdc->xpr);
x = bytes_to_frames(runtime, ptr - prtd->dma_buffer);
if (x == runtime->buffer_size)
x = 0;
return x;
}
static int atmel_pcm_open(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct atmel_runtime_data *prtd;
int ret = 0;
snd_soc_set_runtime_hwparams(substream, &atmel_pcm_hardware);
/* ensure that buffer size is a multiple of period size */
ret = snd_pcm_hw_constraint_integer(runtime,
SNDRV_PCM_HW_PARAM_PERIODS);
if (ret < 0)
goto out;
prtd = kzalloc(sizeof(struct atmel_runtime_data), GFP_KERNEL);
if (prtd == NULL) {
ret = -ENOMEM;
goto out;
}
runtime->private_data = prtd;
out:
return ret;
}
static int atmel_pcm_close(struct snd_soc_component *component,
struct snd_pcm_substream *substream)
{
struct atmel_runtime_data *prtd = substream->runtime->private_data;
kfree(prtd);
return 0;
}
static const struct snd_soc_component_driver atmel_soc_platform = {
.open = atmel_pcm_open,
.close = atmel_pcm_close,
.hw_params = atmel_pcm_hw_params,
.hw_free = atmel_pcm_hw_free,
.prepare = atmel_pcm_prepare,
.trigger = atmel_pcm_trigger,
.pointer = atmel_pcm_pointer,
.pcm_construct = atmel_pcm_new,
};
int atmel_pcm_pdc_platform_register(struct device *dev)
{
return devm_snd_soc_register_component(dev, &atmel_soc_platform,
NULL, 0);
}
EXPORT_SYMBOL(atmel_pcm_pdc_platform_register);
MODULE_AUTHOR("Sedji Gaouaou <sedji.gaouaou@atmel.com>");
MODULE_DESCRIPTION("Atmel PCM module");
MODULE_LICENSE("GPL");
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