/*-*- linux-c -*-*/

/*

* ALSA <-> SOF PCM I/O plugin

*

* Copyright (c) 2022 by Liam Girdwood <liam.r.girdwood@intel.com>

*

* This library is free software; you can redistribute it and/or modify

* it under the terms of the GNU Lesser General Public License as

* published by the Free Software Foundation; either version 2.1 of

* the License, or (at your option) any later version.

*

* This program is distributed in the hope that it will be useful,

* but WITHOUT ANY WARRANTY; without even the implied warranty of

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

* GNU Lesser General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public

* License along with this library; if not, write to the Free Software

* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

*/

#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <unistd.h>

#include <stdlib.h>

#include <assert.h>

#include <errno.h>

#include <sys/mman.h>

#include <sys/stat.h>

#include "common.h"

/*

* Timing

*/

void plug_timespec_add_ms(struct timespec *ts, unsigned long ms)

{

long ns;

long secs = ms / 1000;

/* get ms remainder */

ms = ms - (secs * 1000);

ns = ms * 1000000;

ts->tv_nsec += ns;

if (ts->tv_nsec > 1000000000) {

secs++;

ts->tv_nsec -= 1000000000;

}

ts->tv_sec += (secs + DEBUG_TV_SECS);

}

long plug_timespec_delta_ns(struct timespec *before, struct timespec *after)

{

long ns;

ns = (after->tv_sec - before->tv_sec) * 1000000000;

ns += after->tv_nsec - before->tv_nsec;

return ns;

}

static const char *suffix_name(const char *longname)

{

size_t len = strlen(longname);

int i = len;

/* longname name invalid */

if (len < 1) {

SNDERR("invalid topology long name\n");

return NULL;

}

/* find the last '/' in the longname topology path */

while (--i >= 0) {

if (longname[i] == '/') {

i += 1; /* skip / */

return &longname[i];

}

}

/* no / in topology path, so use full path */

return longname;

}

/*

* IPC

*

* POSIX message queues are used for interprocess IPC messaging.

*/

/*

* Initialise the IPC object.

*/

int plug_mq_init(struct plug_mq_desc *ipc, const char *tplg, const char *type, int index)

{

const char *name = suffix_name(tplg);

if (!name)

return -EINVAL;

snprintf(ipc->queue_name, NAME_SIZE, "/mq-%s-%s-%d", type, name, index);

return 0;

}

/*

* Locking

*

* POSIX semaphores are used to block and synchronise audio between

* different threads and processes.

*/

/*

* Initialise the lock object.

*/

int plug_lock_init(struct plug_sem_desc *lock, const char *tplg, const char *type, int index)

{

const char *name = suffix_name(tplg);

if (!name)

return -EINVAL;

/* semaphores need the leading / */

snprintf(lock->name, NAME_SIZE, "/lock-%s-%s-%d", name, type, index);

return 0;

}

/*

* SHM

*

* Shared memory is used for audio data and audio context sharing between

* threads and processes.

*/

/*

* Initialise the SHM object.

*/

int plug_shm_init(struct plug_shm_desc *shm, const char *tplg, const char *type, int index)

{

const char *name = suffix_name(tplg);

if (!name)

return -EINVAL;

snprintf(shm->name, NAME_SIZE, "/shm-%s-%s-%d", name, type, index);

shm->size = SHM_SIZE;

return 0;

}

/*

* Open an existing shared memory region using the SHM object.

*/

int plug_shm_open(struct plug_shm_desc *shm)

{

struct stat status;

/* open SHM to be used for low latency position */

shm->fd = shm_open(shm->name, O_RDWR,

S_IRWXU | S_IRWXG);

if (shm->fd < 0) {

//SNDERR("failed to open SHM position %s: %s\n",

// shm->name, strerror(errno));

return -errno;

}

fstat(shm->fd, &status);

/* map it locally for context readback */

shm->addr = mmap(NULL, status.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, shm->fd, 0);

if (!shm->addr) {

SNDERR("failed to mmap SHM position%s: %s\n", shm->name, strerror(errno));

return -errno;

}

return 0;

}