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// SPDX-License-Identifier: GPL-2.0
/*
* ALSA Virtual Soundcard
*
* alsa.c - ALSA PCM driver for virtual ALSA card
*
* Copyright (C) 2010-2018 Fiberdyne Systems Pty Ltd
*/
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/initval.h>
#include "alsa.h"
#include "core.h"
static struct avirt_alsa_driver *_driver = NULL;
extern struct snd_pcm_ops pcm_ops;
/**
* pcm_constructor - Constructs the ALSA PCM middle devices for this driver
* @card: The snd_card struct to construct the devices for
* @return 0 on success or error code otherwise
*/
static int pcm_constructor(struct snd_card *card)
{
struct snd_pcm *pcm;
int i;
// Allocate Playback PCM instances
for (i = 0; i < _driver->playback.devices; i++) {
CHK_ERR(snd_pcm_new(card,
_driver->playback.config[i].devicename, i,
1, 1, &pcm));
/** Register driver callbacks */
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
pcm->info_flags = 0;
strcpy(pcm->name, _driver->playback.config[i].devicename);
}
// Allocate Capture PCM instances
for (i = 0; i < _driver->capture.devices; i++) {
CHK_ERR(snd_pcm_new(card, _driver->capture.config[i].devicename,
i, 0, 1, &pcm));
/** Register driver callbacks */
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
pcm->info_flags = 0;
strcpy(pcm->name, _driver->capture.config[i].devicename);
}
return 0;
}
/**
* alloc_dev_config - Allocates memory for ALSA device configuration
* @return: 0 on success or error code otherwise
*/
static int alloc_dev_config(struct avirt_alsa_dev_config **devconfig,
struct avirt_alsa_dev_config *userconfig,
unsigned numdevices)
{
if (numdevices == 0)
return 0;
*devconfig = kzalloc(sizeof(struct avirt_alsa_dev_config) * numdevices,
GFP_KERNEL);
if (!(*devconfig))
return -ENOMEM;
memcpy(*devconfig, userconfig,
sizeof(struct avirt_alsa_dev_config) * numdevices);
return 0;
}
struct avirt_alsa_dev_group *avirt_alsa_get_dev_group(int direction)
{
if (!_driver) {
pr_err("[%s] _driver is NULL", __func__);
return NULL;
}
switch (direction) {
case SNDRV_PCM_STREAM_PLAYBACK:
case SNDRV_PCM_STREAM_CAPTURE:
return &_driver->playback;
default:
pr_err("[%s] Direction must be SNDRV_PCM_STREAM_XXX!",
__func__);
return NULL;
}
}
/**
* avirt_alsa_init - Initializes the ALSA driver
* @return: 0 on success or error code otherwise
*/
int avirt_alsa_init()
{
// Allocate memory for the driver
_driver = kzalloc(sizeof(struct avirt_alsa_driver), GFP_KERNEL);
if (!_driver)
return -ENOMEM;
return 0;
}
/**
* avirt_alsa_configure_pcm- Configure the PCM device
* @config: Device configuration structure array
* @direction: Direction of PCM (SNDRV_PCM_STREAM_XXX)
* @numdevices: Number of devices (array length)
* @return: 0 on success or error code otherwise
*/
int avirt_alsa_configure_pcm(struct avirt_alsa_dev_config *config,
int direction, unsigned numdevices)
{
struct avirt_alsa_dev_group *group;
group = avirt_alsa_get_dev_group(direction);
CHK_NULL(group);
CHK_ERR(alloc_dev_config(&group->config, config, numdevices));
group->devices = numdevices;
return 0;
}
/**
* avirt_alsa_register - Registers the ALSA driver
* @devptr: Platform driver device
* @return: 0 on success or error code otherwise
*/
int avirt_alsa_register(struct platform_device *devptr)
{
struct snd_card *card;
static struct snd_device_ops device_ops;
if (!_driver)
return -EFAULT;
// Create the card instance
CHK_ERR_V(snd_card_new(&devptr->dev, SNDRV_DEFAULT_IDX1, "avirt",
THIS_MODULE, 0, &card),
"Failed to create sound card");
strcpy(card->driver, "avirt-alsa-device");
strcpy(card->shortname, "avirt");
strcpy(card->longname, "A virtual sound card driver for ALSA");
_driver->card = card;
// Create new sound device
CHK_ERR_V((snd_device_new(card, SNDRV_DEV_LOWLEVEL, _driver,
&device_ops)),
"Failed to create sound device");
CHK_ERR((pcm_constructor(card)));
/** Register with the ALSA framework */
CHK_ERR_V(snd_card_register(card), "Device registration failed");
return 0;
}
/**
* avirt_alsa_deregister - Deregisters the ALSA driver
* @devptr: Platform driver device
* @return: 0 on success or error code otherwise
*/
int avirt_alsa_deregister(void)
{
CHK_NULL(_driver->card);
snd_card_free(_driver->card);
CHK_NULL(_driver->playback.config);
kfree(_driver->playback.config);
CHK_NULL(_driver->capture.config);
kfree(_driver->capture.config);
CHK_NULL(_driver);
kfree(_driver);
return 0;
}
/**
* pcm_buff_complete_cb - PCM buffer complete callback
* @substreamid: pointer to ALSA PCM substream
* @return 0 on success or error code otherwise
*
* This should be called from a child Audio Path once it has finished processing
* the pcm buffer
*/
int pcm_buff_complete_cb(struct snd_pcm_substream *substream)
{
// Notify ALSA middle layer of the elapsed period boundary
snd_pcm_period_elapsed(substream);
return 0;
}
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