linux/sound/core/pcm_dmaengine.c
Andreas Pape d1c4420195 ALSA: dmaengine: increment buffer pointer atomically
Setting pointer and afterwards checking for wraparound leads
to the possibility of returning the inconsistent pointer position.

This patch increments buffer pointer atomically to avoid this issue.

Fixes: e7f73a1613 ("ASoC: Add dmaengine PCM helper functions")
Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@de.adit-jv.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2022-09-27 08:55:05 +02:00

474 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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
*/
#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;
dma_cookie_t cookie;
unsigned int pos;
};
static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
const struct snd_pcm_substream *substream)
{
return substream->runtime->private_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.
*
* Return: zero if successful, or a negative error code
*/
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;
int bits;
bits = params_physical_width(params);
if (bits < 8 || bits > 64)
return -EINVAL;
else if (bits == 8)
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
else if (bits == 16)
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
else if (bits == 24)
buswidth = DMA_SLAVE_BUSWIDTH_3_BYTES;
else if (bits <= 32)
buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
else
buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
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;
}
slave_config->device_fc = false;
return 0;
}
EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);
/**
* snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
* using DAI DMA data.
* @substream: PCM substream
* @dma_data: DAI DMA data
* @slave_config: DMA slave configuration
*
* Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width
* fields of the DMA slave config from the same fields of the DAI DMA
* data struct. The src and dst fields will be initialized depending on the
* direction of the substream. If the substream is a playback stream the dst
* fields will be initialized, if it is a capture stream the src fields will be
* initialized. The {dst,src}_addr_width field will only be initialized if the
* SND_DMAENGINE_PCM_DAI_FLAG_PACK flag is set or if the addr_width field of
* the DAI DMA data struct is not equal to DMA_SLAVE_BUSWIDTH_UNDEFINED. If
* both conditions are met the latter takes priority.
*/
void snd_dmaengine_pcm_set_config_from_dai_data(
const struct snd_pcm_substream *substream,
const struct snd_dmaengine_dai_dma_data *dma_data,
struct dma_slave_config *slave_config)
{
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
slave_config->dst_addr = dma_data->addr;
slave_config->dst_maxburst = dma_data->maxburst;
if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
slave_config->dst_addr_width =
DMA_SLAVE_BUSWIDTH_UNDEFINED;
if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
slave_config->dst_addr_width = dma_data->addr_width;
} else {
slave_config->src_addr = dma_data->addr;
slave_config->src_maxburst = dma_data->maxburst;
if (dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK)
slave_config->src_addr_width =
DMA_SLAVE_BUSWIDTH_UNDEFINED;
if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
slave_config->src_addr_width = dma_data->addr_width;
}
slave_config->peripheral_config = dma_data->peripheral_config;
slave_config->peripheral_size = dma_data->peripheral_size;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
static void dmaengine_pcm_dma_complete(void *arg)
{
unsigned int new_pos;
struct snd_pcm_substream *substream = arg;
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
new_pos = prtd->pos + snd_pcm_lib_period_bytes(substream);
if (new_pos >= snd_pcm_lib_buffer_bytes(substream))
new_pos = 0;
prtd->pos = new_pos;
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;
unsigned long flags = DMA_CTRL_ACK;
direction = snd_pcm_substream_to_dma_direction(substream);
if (!substream->runtime->no_period_wakeup)
flags |= DMA_PREP_INTERRUPT;
prtd->pos = 0;
desc = dmaengine_prep_dma_cyclic(chan,
substream->runtime->dma_addr,
snd_pcm_lib_buffer_bytes(substream),
snd_pcm_lib_period_bytes(substream), direction, flags);
if (!desc)
return -ENOMEM;
desc->callback = dmaengine_pcm_dma_complete;
desc->callback_param = substream;
prtd->cookie = dmaengine_submit(desc);
return 0;
}
/**
* snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
* @substream: PCM substream
* @cmd: Trigger command
*
* This function can be used as the PCM trigger callback for dmaengine based PCM
* driver implementations.
*
* Return: 0 on success, a negative error code otherwise
*/
int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
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:
if (runtime->info & SNDRV_PCM_INFO_PAUSE)
dmaengine_pause(prtd->dma_chan);
else
dmaengine_terminate_async(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
dmaengine_pause(prtd->dma_chan);
break;
case SNDRV_PCM_TRIGGER_STOP:
dmaengine_terminate_async(prtd->dma_chan);
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);
/**
* snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
* @substream: PCM substream
*
* This function is deprecated and should not be used by new drivers, as its
* results may be unreliable.
*
* Return: PCM position in frames
*/
snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(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_no_residue);
/**
* 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.
*
* Return: PCM position in frames
*/
snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
struct dma_tx_state state;
enum dma_status status;
unsigned int buf_size;
unsigned int pos = 0;
status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
buf_size = snd_pcm_lib_buffer_bytes(substream);
if (state.residue > 0 && state.residue <= buf_size)
pos = buf_size - state.residue;
runtime->delay = bytes_to_frames(runtime,
state.in_flight_bytes);
}
return bytes_to_frames(runtime, pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
/**
* snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
* @filter_fn: Filter function used to request the DMA channel
* @filter_data: Data passed to the DMA filter function
*
* This function request a DMA channel for usage with dmaengine PCM.
*
* Return: NULL or the requested DMA channel
*/
struct dma_chan *snd_dmaengine_pcm_request_channel(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);
return dma_request_channel(mask, filter_fn, filter_data);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);
/**
* snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
* @substream: PCM substream
* @chan: DMA channel to use for data transfers
*
* 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 available to your pcm driver implementation.
*
* Return: 0 on success, a negative error code otherwise
*/
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
struct dma_chan *chan)
{
struct dmaengine_pcm_runtime_data *prtd;
int ret;
if (!chan)
return -ENXIO;
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;
prtd->dma_chan = chan;
substream->runtime->private_data = prtd;
return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
/**
* snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
* @substream: PCM substream
* @filter_fn: Filter function used to request the DMA channel
* @filter_data: Data passed to the DMA filter function
*
* 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 available to your pcm driver implementation.
*
* Return: 0 on success, a negative error code otherwise
*/
int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
dma_filter_fn filter_fn, void *filter_data)
{
return snd_dmaengine_pcm_open(substream,
snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);
/**
* snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
* @substream: PCM substream
*
* Return: 0 on success, a negative error code otherwise
*/
int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
dmaengine_synchronize(prtd->dma_chan);
kfree(prtd);
return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);
/**
* snd_dmaengine_pcm_close_release_chan - Close a dmaengine based PCM
* substream and release channel
* @substream: PCM substream
*
* Releases the DMA channel associated with the PCM substream.
*
* Return: zero if successful, or a negative error code
*/
int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
{
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
dmaengine_synchronize(prtd->dma_chan);
dma_release_channel(prtd->dma_chan);
kfree(prtd);
return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);
/**
* snd_dmaengine_pcm_refine_runtime_hwparams - Refine runtime hw params
* @substream: PCM substream
* @dma_data: DAI DMA data
* @hw: PCM hw params
* @chan: DMA channel to use for data transfers
*
* This function will query DMA capability, then refine the pcm hardware
* parameters.
*
* Return: 0 on success, a negative error code otherwise
*/
int snd_dmaengine_pcm_refine_runtime_hwparams(
struct snd_pcm_substream *substream,
struct snd_dmaengine_dai_dma_data *dma_data,
struct snd_pcm_hardware *hw,
struct dma_chan *chan)
{
struct dma_slave_caps dma_caps;
u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
snd_pcm_format_t i;
int ret = 0;
if (!hw || !chan || !dma_data)
return -EINVAL;
ret = dma_get_slave_caps(chan, &dma_caps);
if (ret == 0) {
if (dma_caps.cmd_pause && dma_caps.cmd_resume)
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.
*/
pcm_for_each_format(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 |= pcm_format_to_bits(i);
break;
default:
/* Unsupported types */
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_refine_runtime_hwparams);
MODULE_LICENSE("GPL");