audio_utils.c

// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <assert.h>
#include <dirent.h>
#include <linux/input.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <cras_client.h>

#include "audio_utils.h"

static const size_t MAX_IONODES = 20;
static int aud_verbose = 0;

/* These variables are shared with the report thread. */
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
static int hdmi_audio_available;

static struct cras_client *client;
static enum {
  CLIENT_INIT,
  CLIENT_CREATED,
  CLIENT_CONNECTED,
  CLIENT_THREAD_RUN,
  CLIENT_READY,
} client_status;

static int connect_to_server()
{
  int err = 0;
  switch (client_status) {
  case CLIENT_INIT:
    err = cras_client_create(&client);
    if (err) {
      printf("Audio: failed to create client\n");
      return err;
    }
    client_status = CLIENT_CREATED;
    // fallthrough
  case CLIENT_CREATED:
    err = cras_client_connect(client);
    if (err) {
      printf("Audio: failed to connect to server\n");
      return err;
    }
    client_status = CLIENT_CONNECTED;
    // fallthrough
  case CLIENT_CONNECTED:
    err = cras_client_run_thread(client);
    if (err) {
      printf("Audio: failed to run client thread\n");
      return err;
    }
    client_status = CLIENT_THREAD_RUN;
    // fallthrough
  case CLIENT_THREAD_RUN:
    err = cras_client_connected_wait(client);
    if (err) {
      printf("Audio: failed to wait connected.\n");
      return err;
    }
    client_status = CLIENT_READY;
    printf("Audio: client ready\n");
    // fallthrough
  case CLIENT_READY:
  default:
    return 0;
  }
}

/* Sends the availability message to server. Returns 0 if successful, -1
 * otherwise. */
static int send_state_to_server(int available)
{
  size_t num_devs = 0;
  size_t num_nodes = MAX_IONODES;
  struct cras_ionode_info nodes[MAX_IONODES];
  int rc, i;

  if (connect_to_server() != 0)
    return -1;

  rc = cras_client_get_output_devices(client, NULL, nodes, &num_devs,
                                      &num_nodes);
  if (rc < 0) {
    printf("Audio: cannot get output nodes\n");
    return -1;
  }

  for (i = 0; i < num_nodes; i++) {
    if (!strcmp(nodes[i].name, "IEC958")) {
      cras_node_id_t node_id = cras_make_node_id(nodes[i].iodev_idx,
                                                 nodes[i].ionode_idx);
      cras_client_set_node_attr(client, node_id, IONODE_ATTR_PLUGGED,
                                available);
      return 0;
    }
  }

  printf("Audio: IEC959 node is not found\n");
  return -1;
}

/* A thread which reports the hdmi audio state to the server. */
static void *report_thread(void *arg)
{
  /* The state that has been reported to the server successfully. */
  int reported = 0;
  int available;

  while (1)
  {
    /* Wait until the availablity changes */
    pthread_mutex_lock(&mutex);
    while (hdmi_audio_available == reported)
      pthread_cond_wait(&cond, &mutex);
    available = hdmi_audio_available;
    pthread_mutex_unlock(&mutex);

    /* Report the new state */
    if (send_state_to_server(available) == 0) {
      reported = available;
    } else {
      /* If we failed to connect to the server, sleep for five seconds and
       * retry. */
      sleep(5);
    }
  }
}

int audio_init(int verbose)
{
  pthread_t thread;
  aud_verbose = verbose;
  if (aud_verbose) printf("Audio: init\n");
  pthread_create(&thread, NULL, report_thread, NULL);
  return 0;
}

void audio_to_hdmi(int available)
{
  if (available == hdmi_audio_available)
    return;
  if (aud_verbose) printf("Audio: Set HDMI audio output to %s\n",
                          available ? "Available" : "Unavailable");
  pthread_mutex_lock(&mutex);
  hdmi_audio_available = available;
  pthread_cond_signal(&cond);
  pthread_mutex_unlock(&mutex);
}