utils/src/bt_utils.c

/******************************************************************************
 *
 *  Copyright (C) 2012 Broadcom Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

/************************************************************************************
 *
 *  Filename:      bt_utils.c
 *
 *  Description:   Miscellaneous helper functions
 *
 *
 ***********************************************************************************/

#define LOG_TAG "bt_utils"

#include "bt_utils.h"

#include <errno.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <unistd.h>

#include <utils/ThreadDefs.h>
#include <cutils/sched_policy.h>

// TODO(armansito): cutils/properties.h is only being used to pull-in runtime
// settings on Android. Remove this conditional include once we have a generic
// way to obtain system properties.
#if !defined(OS_GENERIC)
#include <cutils/properties.h>
#endif  // !defined(OS_GENERIC)

#include "bt_types.h"
#include "btcore/include/module.h"
#include "osi/include/compat.h"
#include "osi/include/log.h"

/*******************************************************************************
**  Type definitions for callback functions
********************************************************************************/
static pthread_once_t g_DoSchedulingGroupOnce[TASK_HIGH_MAX];
static BOOLEAN g_DoSchedulingGroup[TASK_HIGH_MAX];
static pthread_mutex_t         gIdxLock;
static int g_TaskIdx;
static int g_TaskIDs[TASK_HIGH_MAX];
#define INVALID_TASK_ID  (-1)

static future_t *init(void) {
  int i;
  pthread_mutexattr_t lock_attr;

  for(i = 0; i < TASK_HIGH_MAX; i++) {
    g_DoSchedulingGroupOnce[i] = PTHREAD_ONCE_INIT;
    g_DoSchedulingGroup[i] = TRUE;
    g_TaskIDs[i] = INVALID_TASK_ID;
  }

  pthread_mutexattr_init(&lock_attr);
  pthread_mutex_init(&gIdxLock, &lock_attr);
  return NULL;
}

static future_t *clean_up(void) {
  pthread_mutex_destroy(&gIdxLock);
  return NULL;
}

EXPORT_SYMBOL const module_t bt_utils_module = {
  .name = BT_UTILS_MODULE,
  .init = init,
  .start_up = NULL,
  .shut_down = NULL,
  .clean_up = clean_up,
  .dependencies = {
    NULL
  }
};

// TODO(armansito): Remove this conditional code once there is a generic way
// to obtain system properties. System properties are only available on
// Android. Don't do the following check if this is a generic build.
#if !defined(OS_GENERIC)
/*****************************************************************************
**
** Function        check_do_scheduling_group
**
** Description     check if it is ok to change schedule group
**
** Returns         void
**
*******************************************************************************/
static void check_do_scheduling_group(void) {
    char buf[PROPERTY_VALUE_MAX];
    int len = property_get("debug.sys.noschedgroups", buf, "");
    if (len > 0) {
        int temp;
        if (sscanf(buf, "%d", &temp) == 1) {
            g_DoSchedulingGroup[g_TaskIdx] = temp == 0;
        }
    }
}
#endif  // !defined(OS_GENERIC)

/*****************************************************************************
**
** Function        raise_priority_a2dp
**
** Description     Raise task priority for A2DP streaming
**
** Returns         void
**
*******************************************************************************/
void raise_priority_a2dp(tHIGH_PRIORITY_TASK high_task) {
    int rc = 0;
    int tid = gettid();
    int priority = ANDROID_PRIORITY_AUDIO;

    pthread_mutex_lock(&gIdxLock);
    g_TaskIdx = high_task;

    // TODO(armansito): Remove this conditional check once we find a solution
    // for system/core on non-Android platforms.
#if defined(OS_GENERIC)
    rc = -1;
#else  // !defined(OS_GENERIC)
    pthread_once(&g_DoSchedulingGroupOnce[g_TaskIdx], check_do_scheduling_group);
    if (g_DoSchedulingGroup[g_TaskIdx]) {
        // set_sched_policy does not support tid == 0
        rc = set_sched_policy(tid, SP_AUDIO_SYS);
    }
#endif  // defined(OS_GENERIC)

    g_TaskIDs[high_task] = tid;
    pthread_mutex_unlock(&gIdxLock);

    if (rc) {
        LOG_WARN(LOG_TAG, "failed to change sched policy, tid %d, err: %d", tid, errno);
    }

    // always use urgent priority for HCI worker thread until we can adjust
    // its prio individually. All other threads can be dynamically adjusted voa
    // adjust_priority_a2dp()

    if (high_task == TASK_HIGH_HCI_WORKER)
       priority = ANDROID_PRIORITY_URGENT_AUDIO;

    if (setpriority(PRIO_PROCESS, tid, priority) < 0) {
        LOG_WARN(LOG_TAG, "failed to change priority tid: %d to %d", tid, priority);
    }
}

/*****************************************************************************
**
** Function        adjust_priority_a2dp
**
** Description     increase the a2dp consumer task priority temporarily when start
**                 audio playing, to avoid overflow the audio packet queue, restore
**                 the a2dp consumer task priority when stop audio playing.
**
** Returns         void
**
*******************************************************************************/
void adjust_priority_a2dp(int start) {
    int priority = start ? ANDROID_PRIORITY_URGENT_AUDIO : ANDROID_PRIORITY_AUDIO;
    int tid;
    int i;

    for (i = 0; i < TASK_HIGH_MAX; i++)
    {
        tid = g_TaskIDs[i];
        if (tid != INVALID_TASK_ID)
        {
            if (setpriority(PRIO_PROCESS, tid, priority) < 0)
            {
                LOG_WARN(LOG_TAG, "failed to change priority tid: %d to %d", tid, priority);
            }
        }
    }
}