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/* pcm_hw.c
**
** Copyright (c) 2019, The Linux Foundation.
** Copyright 2021, The Android Open Source Project
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above
** copyright notice, this list of conditions and the following
** disclaimer in the documentation and/or other materials provided
** with the distribution.
** * Neither the name of The Linux Foundation nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
** ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
** BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
** CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
** SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
** BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
** OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
** IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/ioctl.h>
#include <time.h>
#include <sound/asound.h>
#include <tinyalsa/asoundlib.h>
#include "pcm_io.h"
struct pcm_hw_data {
/** Card number of the pcm device */
unsigned int card;
/** Device number for the pcm device */
unsigned int device;
/** File descriptor to the pcm device file node */
int fd;
/** Pointer to the pcm node from snd card definiton */
struct snd_node *node;
};
static void pcm_hw_close(void *data)
{
struct pcm_hw_data *hw_data = data;
if (hw_data->fd >= 0)
close(hw_data->fd);
free(hw_data);
}
static int pcm_hw_ioctl(void *data, unsigned int cmd, ...)
{
struct pcm_hw_data *hw_data = data;
va_list ap;
void *arg;
va_start(ap, cmd);
arg = va_arg(ap, void *);
va_end(ap);
return ioctl(hw_data->fd, cmd, arg);
}
static int pcm_hw_poll(void *data __attribute__((unused)),
struct pollfd *pfd, nfds_t nfds, int timeout)
{
return poll(pfd, nfds, timeout);
}
static void *pcm_hw_mmap(void *data, void *addr, size_t length, int prot,
int flags, off_t offset)
{
struct pcm_hw_data *hw_data = data;
return mmap(addr, length, prot, flags, hw_data->fd, offset);
}
static int pcm_hw_munmap(void *data __attribute__((unused)), void *addr, size_t length)
{
return munmap(addr, length);
}
static int pcm_hw_open(unsigned int card, unsigned int device,
unsigned int flags, void **data, struct snd_node *node)
{
struct pcm_hw_data *hw_data;
char fn[256];
int fd;
hw_data = calloc(1, sizeof(*hw_data));
if (!hw_data) {
return -ENOMEM;
}
snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
flags & PCM_IN ? 'c' : 'p');
// Open the device with non-blocking flag to avoid to be blocked in kernel when all of the
// substreams of this PCM device are opened by others.
fd = open(fn, O_RDWR | O_NONBLOCK);
if (fd < 0) {
free(hw_data);
return fd;
}
if ((flags & PCM_NONBLOCK) == 0) {
// Set the file descriptor to blocking mode.
if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK) < 0) {
fprintf(stderr, "failed to set to blocking mode on %s", fn);
close(fd);
free(hw_data);
return -ENODEV;
}
}
hw_data->card = card;
hw_data->device = device;
hw_data->fd = fd;
hw_data->node = node;
*data = hw_data;
return fd;
}
const struct pcm_ops hw_ops = {
.open = pcm_hw_open,
.close = pcm_hw_close,
.ioctl = pcm_hw_ioctl,
.mmap = pcm_hw_mmap,
.munmap = pcm_hw_munmap,
.poll = pcm_hw_poll,
};
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