diff options
Diffstat (limited to 'pcm.c')
| -rw-r--r-- | pcm.c | 332 |
1 files changed, 332 insertions, 0 deletions
@@ -0,0 +1,332 @@ +// 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) + +#define DO_AUDIOPATH_CB(ap, callback, substream, ...) \ + (((ap)->pcm_ops->callback) ? \ + (ap)->pcm_ops->callback((substream), ##__VA_ARGS__) : \ + 0) + +/** + * 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_audiopath *audiopath; + struct snd_avirt_stream *stream; + struct snd_pcm_hardware *hw; + unsigned int chans = 0; + + stream = snd_avirt_stream_find_by_device(substream->pcm->device); + audiopath = snd_avirt_audiopath_get(stream->map); + CHK_NULL_V(audiopath, "Cannot find Audio Path uid: '%s'!", stream->map); + substream->private_data = audiopath; + + // Copy the hw params from the audiopath to the pcm + hw = &substream->runtime->hw; + memcpy(hw, audiopath->hw, sizeof(struct snd_pcm_hardware)); + + stream = snd_avirt_stream_find_by_device(substream->pcm->device); + if (IS_ERR_VALUE(stream) || !stream) + return PTR_ERR(stream); + + // 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_close - Implements 'close' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * + * This is called when a PCM substream is closed. + * + * Returns 0 on success or error code otherwise. + */ +static int pcm_close(struct snd_pcm_substream *substream) +{ + // Do additional Audio Path 'close' callback + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), close, + 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; + struct snd_avirt_audiopath *audiopath; + struct snd_avirt_stream *stream; + + stream = snd_avirt_stream_find_by_device(substream->pcm->device); + if (IS_ERR_VALUE(stream) || !stream) + return PTR_ERR(stream); + + if ((params_channels(hw_params) > stream->channels) || + (params_channels(hw_params) < stream->channels)) { + D_ERRORK("Requested number of channels: %d not supported", + params_channels(hw_params)); + return -EINVAL; + } + + audiopath = ((struct snd_avirt_audiopath *)substream->private_data); + bufsz = params_buffer_bytes(hw_params) * audiopath->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 *)substream->private_data), + hw_free, substream); + + return snd_pcm_lib_free_vmalloc_buffer(substream); +} + +/** + * pcm_prepare - Implements 'prepare' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * + * The format rate, sample rate, etc., can be set here. This callback can be + * called many times at each setup. This function is also used to handle overrun + * and underrun conditions when we try and resync the DMA (if we're using DMA). + * + * Returns 0 on success or error code otherwise. + */ +static int pcm_prepare(struct snd_pcm_substream *substream) +{ + // Do additional Audio Path 'prepare' callback + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + prepare, substream); +} + +/** + * pcm_trigger - Implements 'trigger' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * @cmd: action to be performed (start or stop) + * + * This is called when the PCM is started, stopped or paused. The action + * indicated action is specified in the second argument, SNDRV_PCM_TRIGGER_XXX + * + * Returns 0 on success or error code otherwise. + */ +static int pcm_trigger(struct snd_pcm_substream *substream, int cmd) +{ + switch (cmd) { + case SNDRV_PCM_TRIGGER_START: + case SNDRV_PCM_TRIGGER_RESUME: + case SNDRV_PCM_TRIGGER_STOP: + case SNDRV_PCM_TRIGGER_SUSPEND: + break; + default: + D_ERRORK("Invalid trigger cmd: %d", cmd); + return -EINVAL; + } + + // Do additional Audio Path 'trigger' callback + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + trigger, substream, cmd); +} + +/** + * pcm_pointer - Implements 'pointer' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * + * This gets called when the user space needs a DMA buffer index. IO errors will + * be generated if the index does not increment, or drives beyond the frame + * threshold of the buffer itself. + * + * Returns the current hardware buffer frame index. + */ +static snd_pcm_uframes_t pcm_pointer(struct snd_pcm_substream *substream) +{ + // Do additional Audio Path 'pointer' callback + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + pointer, substream); +} + +/** + * pcm_pointer - Implements 'get_time_info' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * @system_ts + * @audio_ts + * @audio_tstamp_config + * @audio_tstamp_report + * + * Generic way to get system timestamp and audio timestamp info + * + * Returns 0 on success or error code otherwise + */ +static int pcm_get_time_info( + struct snd_pcm_substream *substream, struct timespec *system_ts, + struct timespec *audio_ts, + struct snd_pcm_audio_tstamp_config *audio_tstamp_config, + struct snd_pcm_audio_tstamp_report *audio_tstamp_report) +{ + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + get_time_info, substream, system_ts, audio_ts, + audio_tstamp_config, audio_tstamp_report); +} + +/** + * pcm_copy_user - Implements 'copy_user' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * @channel: + * @pos: The offset in the DMA + * @src: Audio PCM data from the user space + * @count: + * + * This is where we need to copy user audio PCM data into the sound driver + * + * Returns 0 on success or error code otherwise. + * + */ +static int pcm_copy_user(struct snd_pcm_substream *substream, int channel, + snd_pcm_uframes_t pos, void __user *src, + snd_pcm_uframes_t count) +{ + // struct snd_pcm_runtime *runtime; + // int offset; + + // runtime = substream->runtime; + // offset = frames_to_bytes(runtime, pos); + + // Do additional Audio Path 'copy_user' callback + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + copy_user, substream, channel, pos, src, count); +} + +/** + * pcm_copy_kernel - Implements 'copy_kernel' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * @channel: + * @pos: The offset in the DMA + * @src: Audio PCM data from the user space + * @count: + * + * This is where we need to copy kernel audio PCM data into the sound driver + * + * Returns 0 on success or error code otherwise. + * + */ +static int pcm_copy_kernel(struct snd_pcm_substream *substream, int channel, + unsigned long pos, void *buf, unsigned long count) +{ + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + copy_kernel, substream, channel, pos, buf, count); +} + +/** + * pcm_ack - Implements 'ack' callback for PCM middle layer + * @substream: pointer to ALSA PCM substream + * + * This is where we need to ack + * + * Returns 0 on success or error code otherwise. + * + */ +static int pcm_ack(struct snd_pcm_substream *substream) +{ + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), ack, + substream); +} + +static int pcm_silence(struct snd_pcm_substream *substream, int channel, + snd_pcm_uframes_t pos, snd_pcm_uframes_t count) +{ + return DO_AUDIOPATH_CB( + ((struct snd_avirt_audiopath *)substream->private_data), + fill_silence, substream, channel, pos, count); +} + +struct snd_pcm_ops pcm_ops = { + .open = pcm_open, + .close = pcm_close, + .ioctl = snd_pcm_lib_ioctl, + .hw_params = pcm_hw_params, + .hw_free = pcm_hw_free, + .prepare = pcm_prepare, + .trigger = pcm_trigger, + .pointer = pcm_pointer, + .get_time_info = pcm_get_time_info, + .fill_silence = pcm_silence, + .copy_user = pcm_copy_user, + .copy_kernel = pcm_copy_kernel, + .page = snd_pcm_lib_get_vmalloc_page, + .ack = pcm_ack, +}; |