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// SPDX-License-Identifier: GPL-2.0
/*
* AVIRT - ALSA Virtual Soundcard
*
* Copyright (c) 2010-2018 Fiberdyne Systems Pty Ltd
*
* pcm.c - AVIRT PCM interface
*/
#include "core.h"
#define D_LOGNAME "pcm"
#define D_INFOK(fmt, args...) DINFO(D_LOGNAME, fmt, ##args)
#define D_PRINTK(fmt, args...) DDEBUG(D_LOGNAME, fmt, ##args)
#define D_ERRORK(fmt, args...) DERROR(D_LOGNAME, fmt, ##args)
/**
* DO_AUDIOPATH_CB - Used to call into an Audio Path's ALSA PCM callback from
* AVIRT, where AVIRT's own callback must be attended to first.
*/
#define DO_AUDIOPATH_CB(ap, callback, substream, ...) \
((!substream->stream) ? \
(((ap)->pcm_playback_ops->callback) ? \
(ap)->pcm_playback_ops->callback((substream), \
##__VA_ARGS__) : \
0) : \
(((ap)->pcm_capture_ops->callback) ? \
(ap)->pcm_capture_ops->callback((substream), \
##__VA_ARGS__) : \
0))
#define PRIVATE_DATA(substream) \
((struct snd_avirt_private_data *)substream->private_data)
/**
* snd_avirt_pcm_period_elapsed - PCM buffer complete callback
* @substreamid: pointer to ALSA PCM substream
*
* This should be called from a child Audio Path once it has finished
* processing the pcm buffer
*/
void snd_avirt_pcm_period_elapsed(struct snd_pcm_substream *substream)
{
// Notify ALSA middle layer of the elapsed period boundary
snd_pcm_period_elapsed(substream);
}
EXPORT_SYMBOL_GPL(snd_avirt_pcm_period_elapsed);
/*******************************************************************************
* ALSA PCM Callbacks
******************************************************************************/
/**
* pcm_open - Implements 'open' callback for PCM middle layer
* @substream: pointer to ALSA PCM substream
*
* This is called when an ALSA PCM substream is opened. The substream device
* is configured here.
*
* Returns 0 on success or error code otherwise.
*/
static int pcm_open(struct snd_pcm_substream *substream)
{
struct snd_avirt_private_data *avirt_private_data;
struct snd_avirt_audiopath *audiopath;
struct snd_avirt_stream *stream;
struct snd_pcm_hardware *hw;
unsigned int chans = 0;
// Find the Audio Path mapped to this device
stream = snd_avirt_stream_find_by_device(substream->pcm->device);
if (IS_ERR_VALUE(stream) || !stream)
return PTR_ERR(stream);
audiopath = snd_avirt_audiopath_get(stream->map);
CHK_NULL_V(audiopath, "Cannot find Audio Path uid: '%s'!", stream->map);
// Set the private data's Audio Path
avirt_private_data = substream->private_data;
avirt_private_data->audiopath = audiopath;
// Copy the hw params from the audiopath to the pcm
hw = &substream->runtime->hw;
memcpy(hw, audiopath->hw, sizeof(struct snd_pcm_hardware));
// Setup remaining hw properties
chans = stream->channels;
hw->channels_min = chans;
hw->channels_max = chans;
// Do additional Audio Path 'open' callback
return DO_AUDIOPATH_CB(audiopath, open, substream);
}
/**
* pcm_hw_params - Implements 'hw_params' callback for PCM middle layer
* @substream: pointer to ALSA PCM substream
* @hw_params: contains the hardware parameters for the PCM
*
* This is called when the hardware parameters are set, including buffer size,
* the period size, the format, etc. The buffer allocation should be done here.
*
* Returns 0 on success or error code otherwise.
*/
static int pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
int retval;
size_t bufsz;
/* Check supported channels */
if ((params_channels(hw_params) <
substream->runtime->hw.channels_min) ||
(params_channels(hw_params) >
substream->runtime->hw.channels_max)) {
D_ERRORK("Requested number of channels: %d not supported",
params_channels(hw_params));
return -EINVAL;
}
bufsz = params_buffer_bytes(hw_params) *
substream->runtime->hw.periods_max;
retval = snd_pcm_lib_alloc_vmalloc_buffer(substream, bufsz);
if (retval < 0)
D_ERRORK("pcm: buffer allocation failed: %d", retval);
return retval;
}
/**
* pcm_hw_free - Implements 'hw_free' callback for PCM middle layer
* @substream: pointer to ALSA PCM substream
*
* Release the resources allocated via 'hw_params'.
* This function is always called before the 'close' callback .
*
* Returns 0 on success or error code otherwise.
*/
static int pcm_hw_free(struct snd_pcm_substream *substream)
{
int err;
// Do additional Audio Path 'hw_free' callback
err = DO_AUDIOPATH_CB(
(struct snd_avirt_audiopath *)PRIVATE_DATA(substream)->audiopath,
hw_free, substream);
return snd_pcm_lib_free_vmalloc_buffer(substream);
}
/**
* Default PCM ops table. Selected PCM ops must pass through AVIRT before
* calling back to their respective Audio Paths
*/
struct snd_pcm_ops pcm_ops_avirt = {
.open = pcm_open,
.ioctl = snd_pcm_lib_ioctl,
.hw_params = pcm_hw_params,
.hw_free = pcm_hw_free,
.page = snd_pcm_lib_get_vmalloc_page,
};
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