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// SPDX-License-Identifier: GPL-2.0
/*
* ALSA Virtual Soundcard
*
* loopback_audiopath.c - AVIRT sample Audio Path definition
*
* Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <avirt/core.h>
MODULE_AUTHOR("JOSHANNE <james.oshannessy@fiberdyne.com.au>");
MODULE_AUTHOR("MFARRUGI <mark.farrugia@fiberdyne.com.au>");
MODULE_DESCRIPTION("Sample Audio Path Module Interface");
MODULE_LICENSE("GPL v2");
static struct avirt_coreinfo *coreinfo;
/*******************************************************************************
* Audio Path ALSA PCM Callbacks
******************************************************************************/
static int loopback_pcm_open(struct snd_pcm_substream *substream)
{
return 0;
}
static int loopback_pcm_close(struct snd_pcm_substream *substream)
{
return 0;
}
static snd_pcm_uframes_t
loopback_pcm_pointer(struct snd_pcm_substream *substream)
{
return 0;
}
static int loopback_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:
return 0;
}
return -EINVAL;
}
static int loopback_pcm_prepare(struct snd_pcm_substream *substream)
{
return 0;
}
static struct snd_pcm_ops loopbackap_pcm_ops = {
.open = loopback_pcm_open,
.close = loopback_pcm_close,
.prepare = loopback_pcm_prepare,
.pointer = loopback_pcm_pointer,
.trigger = loopback_pcm_trigger,
};
/*******************************************************************************
* Loopback Audio Path AVIRT registration
******************************************************************************/
static struct snd_pcm_hardware loopbackap_hw = {
.formats = SNDRV_PCM_FMTBIT_S16_LE,
.info = (SNDRV_PCM_INFO_INTERLEAVED // Channel interleaved audio
| SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP |
SNDRV_PCM_INFO_MMAP_VALID),
.rates = SNDRV_PCM_RATE_48000,
.rate_min = 48000,
.rate_max = 48000,
.periods_min = 1,
.periods_max = 8,
};
static struct avirt_audiopath loopbackap_module = {
.name = "Loopback Audio Path",
.version = { 0, 0, 1 },
.value = 10,
.hw = &loopbackap_hw,
.pcm_ops = &loopbackap_pcm_ops,
.blocksize = 512,
};
static int __init loopback_init(void)
{
int err = 0;
pr_info("init()\n");
err = avirt_register_audiopath(&loopbackap_module, &coreinfo);
if ((err < 0) || (!coreinfo)) {
pr_err("%s: coreinfo is NULL!\n", __func__);
return err;
}
return err;
}
static void __exit loopback_exit(void)
{
pr_info("exit()\n");
avirt_deregister_audiopath(&loopbackap_module);
}
module_init(loopback_init);
module_exit(loopback_exit);
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