/* 
 * Copyright (c) 2015 Nordic Semiconductor ASA
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 *   1. Redistributions of source code must retain the above copyright notice, this list 
 *      of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA 
 *      integrated circuit in a product or a software update for such product, 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.
 *
 *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be 
 *      used to endorse or promote products derived from this software without specific prior 
 *      written permission.
 *
 *   4. This software, with or without modification, must only be used with a 
 *      Nordic Semiconductor ASA integrated circuit.
 *
 *   5. Any software provided in binary or object form under this license must not be reverse 
 *      engineered, decompiled, modified and/or disassembled. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */



#include "pm_mutex.h"

#include <stdbool.h>
#include <string.h>
#include "nrf_error.h"
#include "app_util_platform.h"



/**@brief Locks the mutex defined by the mask.
 *
 * @param p_mutex pointer to the mutex storage.
 * @param mutex_mask the mask identifying the mutex position.
 *
 * @retval true if the mutex could be locked.
 * @retval false if the mutex was already locked.
 */
static bool lock_by_mask(uint8_t * p_mutex, uint8_t mutex_mask)
{
    bool success = false;

    if ( (*p_mutex & mutex_mask) == 0 )
    {
        CRITICAL_REGION_ENTER();
        if ( (*p_mutex & mutex_mask) == 0 )
        {
            *p_mutex |= mutex_mask;

            success = true;
        }
        CRITICAL_REGION_EXIT();
    }

    return ( success );
}


void pm_mutex_init(uint8_t * p_mutex, uint16_t mutex_size)
{
    if (p_mutex != NULL)
    {
        memset(&p_mutex[0], 0, MUTEX_STORAGE_SIZE(mutex_size));
    }
}


bool pm_mutex_lock(uint8_t * p_mutex, uint16_t mutex_id)
{
    if (p_mutex != NULL)
    {
        return ( lock_by_mask(&(p_mutex[mutex_id >> 3]), (1 << (mutex_id & 0x07))) );
    }
    else
    {
        return false;
    }
}


void pm_mutex_unlock(uint8_t * p_mutex, uint16_t mutex_id)
{
    uint8_t mutex_base = mutex_id >> 3;
    uint8_t mutex_mask = (1 << (mutex_id & 0x07));

    if   ((p_mutex != NULL)
       && (p_mutex[mutex_base] & mutex_mask))
    {
        CRITICAL_REGION_ENTER();
        p_mutex[mutex_base] &= ~mutex_mask;
        CRITICAL_REGION_EXIT();
    }
}


uint16_t pm_mutex_lock_first_available(uint8_t * p_mutex, uint16_t mutex_size)
{
    if (p_mutex != NULL)
    {
        for ( uint16_t i = 0; i < mutex_size; i++ )
        {
            if ( lock_by_mask(&(p_mutex[i >> 3]), 1 << (i & 0x07)) )
            {
                return ( i );
            }
        }
    }

    return ( mutex_size );
}


bool pm_mutex_lock_status_get(uint8_t * p_mutex, uint16_t mutex_id)
{
    if (p_mutex != NULL)
    {
        return ( (p_mutex[mutex_id >> 3] & (1 << (mutex_id & 0x07))) );
    }
    else
    {
        return true;
    }
}