Refactor alsa-pcm.c to pcm.c

No need for alsa- prefix any longer

Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>

1 files changed, 332 insertions, 0 deletions

diff --git a/pcm.c b/pcm.c
new file mode 100644
index 0000000..babc8b6
--- /dev/null
+++ b/pcm.c
@@ -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,
+};