aboutsummaryrefslogtreecommitdiff
path: root/src/pcm_hw.c
blob: 2383ae006130c6d621f60fef34a9e878a4498d04 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
/* 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,
};