104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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// Copyright (c) 2025 Šerif Rami <ramiserifpersia@gmail.com>
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#include "us144mkii.h"
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/**
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* tascam_playback_open() - Opens the PCM playback substream.
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* @substream: The ALSA PCM substream to open.
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*
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* This function sets the hardware parameters for the playback substream
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* and stores a reference to the substream in the driver's private data.
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*
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* Return: 0 on success.
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*/
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static int tascam_playback_open(struct snd_pcm_substream *substream) {
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struct tascam_card *tascam = snd_pcm_substream_chip(substream);
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substream->runtime->hw = tascam_pcm_hw;
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tascam->playback_substream = substream;
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atomic_set(&tascam->playback_active, 0);
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return 0;
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}
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/**
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* tascam_playback_close() - Closes the PCM playback substream.
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* @substream: The ALSA PCM substream to close.
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*
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* This function clears the reference to the playback substream in the
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* driver's private data.
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*
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* Return: 0 on success.
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*/
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static int tascam_playback_close(struct snd_pcm_substream *substream) {
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struct tascam_card *tascam = snd_pcm_substream_chip(substream);
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tascam->playback_substream = NULL;
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return 0;
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}
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/**
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* tascam_playback_prepare() - Prepares the PCM playback substream for use.
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* @substream: The ALSA PCM substream to prepare.
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*
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* This function initializes playback-related counters.
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*
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* Return: 0 on success.
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*/
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static int tascam_playback_prepare(struct snd_pcm_substream *substream) {
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struct tascam_card *tascam = snd_pcm_substream_chip(substream);
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tascam->driver_playback_pos = 0;
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tascam->playback_frames_consumed = 0;
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return 0;
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}
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/**
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* tascam_playback_pointer() - Returns the current playback pointer position.
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* @substream: The ALSA PCM substream.
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*
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* This function returns the current position of the playback pointer within
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* the ALSA ring buffer, in frames.
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*
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* Return: The current playback pointer position in frames.
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*/
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static snd_pcm_uframes_t
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tascam_playback_pointer(struct snd_pcm_substream *substream) {
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struct tascam_card *tascam = snd_pcm_substream_chip(substream);
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struct snd_pcm_runtime *runtime = substream->runtime;
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u64 pos;
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if (!atomic_read(&tascam->playback_active))
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return 0;
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guard(spinlock_irqsave)(&tascam->lock);
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pos = tascam->playback_frames_consumed;
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if (runtime->buffer_size == 0)
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return 0;
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u64 remainder = do_div(pos, runtime->buffer_size);
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return runtime ? remainder : 0;
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}
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/**
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* tascam_playback_ops - ALSA PCM operations for playback.
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*
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* This structure defines the callback functions for playback stream operations,
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* including open, close, ioctl, hardware parameters, hardware free, prepare,
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* trigger, and pointer.
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*/
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const struct snd_pcm_ops tascam_playback_ops = {
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.open = tascam_playback_open,
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.close = tascam_playback_close,
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.ioctl = snd_pcm_lib_ioctl,
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.hw_params = tascam_pcm_hw_params,
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.hw_free = tascam_pcm_hw_free,
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.prepare = tascam_playback_prepare,
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.trigger = tascam_pcm_trigger,
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.pointer = tascam_playback_pointer,
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};
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