/*
 * FreeRTOS Kernel V10.2.1
 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

/**
 * @file atomic.h
 * @brief FreeRTOS atomic operation support.
 *
 * This file implements atomic by disabling interrupts globally.
 * Implementation with architecture specific atomic instructions
 * are to be provided under each compiler directory.
 */

#ifndef ATOMIC_H
#define ATOMIC_H

#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h must appear in source files before include atomic.h"
#endif

/* Standard includes. */
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Port specific definitions -- entering/exiting critical section.
 * Refer template -- ./lib/FreeRTOS/portable/Compiler/Arch/portmacro.h
 *
 * Every call to ATOMIC_EXIT_CRITICAL() must be closely paired with
 * ATOMIC_ENTER_CRITICAL().
 *  */
#if defined(portSET_INTERRUPT_MASK_FROM_ISR)

/* Nested interrupt scheme is supported in this port. */
#define ATOMIC_ENTER_CRITICAL() \
    UBaseType_t uxCriticalSectionType = portSET_INTERRUPT_MASK_FROM_ISR()

#define ATOMIC_EXIT_CRITICAL() \
    portCLEAR_INTERRUPT_MASK_FROM_ISR(uxCriticalSectionType)

#else

/* Nested interrupt scheme is NOT supported in this port. */
#define ATOMIC_ENTER_CRITICAL() portENTER_CRITICAL()
#define ATOMIC_EXIT_CRITICAL()  portEXIT_CRITICAL()

#endif /* portSET_INTERRUPT_MASK_FROM_ISR() */

/* Port specific definition -- "always inline".
 * Inline is compiler specific, and may not always get inlined depending on your optimization level.
 * Also, inline is considerred as performance optimization for atomic.
 * Thus, if portFORCE_INLINE is not provided by portmacro.h, instead of resulting error,
 * simply define it.
 */
#ifndef portFORCE_INLINE
#define portFORCE_INLINE
#endif

#define ATOMIC_COMPARE_AND_SWAP_SUCCESS 0x1U /**< Compare and swap succeeded, swapped. */
#define ATOMIC_COMPARE_AND_SWAP_FAILURE 0x0U /**< Compare and swap failed, did not swap. */

/*----------------------------- Swap && CAS ------------------------------*/

/**
 * Atomic compare-and-swap
 *
 * @brief Performs an atomic compare-and-swap operation on the specified values.
 *
 * @param[in, out] pDestination  Pointer to memory location from where value is
 *                             to be loaded and checked.
 * @param[in] ulExchange         If condition meets, write this value to memory.
 * @param[in] ulComparand       Swap condition.
 *
 * @return Unsigned integer of value 1 or 0. 1 for swapped, 0 for not swapped.
 *
 * @note This function only swaps *pDestination with ulExchange, if previous
 *     *pDestination value equals ulComparand.
 */
static portFORCE_INLINE uint32_t Atomic_CompareAndSwap_u32(
    uint32_t volatile *pDestination,
    uint32_t ulExchange,
    uint32_t ulComparand)
{
    uint32_t ulReturnValue = ATOMIC_COMPARE_AND_SWAP_FAILURE;

    ATOMIC_ENTER_CRITICAL();

    if (*pDestination == ulComparand) {
        *pDestination = ulExchange;
        ulReturnValue = ATOMIC_COMPARE_AND_SWAP_SUCCESS;
    }

    ATOMIC_EXIT_CRITICAL();

    return ulReturnValue;
}

/**
 * Atomic swap (pointers)
 *
 * @brief Atomically sets the address pointed to by *ppDestination to the value
 *      of *pExchange.
 *
 * @param[in, out] ppDestination  Pointer to memory location from where a pointer
 *                              value is to be loaded and written back to.
 * @param[in] pExchange        Pointer value to be written to *ppDestination.
 *
 * @return The initial value of *ppDestination.
 */
static portFORCE_INLINE void *Atomic_SwapPointers_p32(
    void *volatile *ppDestination,
    void *pExchange)
{
    void *pReturnValue;

    ATOMIC_ENTER_CRITICAL();

    pReturnValue = *ppDestination;

    *ppDestination = pExchange;

    ATOMIC_EXIT_CRITICAL();

    return pReturnValue;
}

/**
 * Atomic compare-and-swap (pointers)
 *
 * @brief Performs an atomic compare-and-swap operation on the specified pointer
 *      values.
 *
 * @param[in, out] ppDestination  Pointer to memory location from where a pointer
 *                              value is to be loaded and checked.
 * @param[in] pExchange        If condition meets, write this value to memory.
 * @param[in] pComparand          Swap condition.
 *
 * @return Unsigned integer of value 1 or 0. 1 for swapped, 0 for not swapped.
 *
 * @note This function only swaps *ppDestination with pExchange, if previous
 *     *ppDestination value equals pComparand.
 */
static portFORCE_INLINE uint32_t Atomic_CompareAndSwapPointers_p32(
    void *volatile *ppDestination,
    void *pExchange, void *pComparand)
{
    uint32_t ulReturnValue = ATOMIC_COMPARE_AND_SWAP_FAILURE;

    ATOMIC_ENTER_CRITICAL();

    if (*ppDestination == pComparand) {
        *ppDestination = pExchange;
        ulReturnValue = ATOMIC_COMPARE_AND_SWAP_SUCCESS;
    }

    ATOMIC_EXIT_CRITICAL();

    return ulReturnValue;
}

/*----------------------------- Arithmetic ------------------------------*/

/**
 * Atomic add
 *
 * @brief Atomically adds count to the value of the specified pointer points to.
 *
 * @param[in,out] pAddend  Pointer to memory location from where value is to be
 *                       loaded and written back to.
 * @param[in] ulCount     Value to be added to *pAddend.
 *
 * @return previous *pAddend value.
 */
static portFORCE_INLINE uint32_t Atomic_Add_u32(
    uint32_t volatile *pAddend,
    uint32_t ulCount)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pAddend;

    *pAddend += ulCount;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic subtract
 *
 * @brief Atomically subtracts count from the value of the specified pointer
 *      pointers to.
 *
 * @param[in,out] pAddend  Pointer to memory location from where value is to be
 *                       loaded and written back to.
 * @param[in] ulCount     Value to be subtract from *pAddend.
 *
 * @return previous *pAddend value.
 */
static portFORCE_INLINE uint32_t Atomic_Subtract_u32(
    uint32_t volatile *pAddend,
    uint32_t ulCount)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pAddend;

    *pAddend -= ulCount;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic increment
 *
 * @brief Atomically increments the value of the specified pointer points to.
 *
 * @param[in,out] pAddend  Pointer to memory location from where value is to be
 *                       loaded and written back to.
 *
 * @return *pAddend value before increment.
 */
static portFORCE_INLINE uint32_t Atomic_Increment_u32(uint32_t volatile *pAddend)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pAddend;

    *pAddend += 1;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic decrement
 *
 * @brief Atomically decrements the value of the specified pointer points to
 *
 * @param[in,out] pAddend  Pointer to memory location from where value is to be
 *                       loaded and written back to.
 *
 * @return *pAddend value before decrement.
 */
static portFORCE_INLINE uint32_t Atomic_Decrement_u32(uint32_t volatile *pAddend)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pAddend;

    *pAddend -= 1;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/*----------------------------- Bitwise Logical ------------------------------*/

/**
 * Atomic OR
 *
 * @brief Performs an atomic OR operation on the specified values.
 *
 * @param [in, out] pDestination  Pointer to memory location from where value is
 *                              to be loaded and written back to.
 * @param [in] ulValue          Value to be ORed with *pDestination.
 *
 * @return The original value of *pDestination.
 */
static portFORCE_INLINE uint32_t Atomic_OR_u32(
    uint32_t volatile *pDestination,
    uint32_t ulValue)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pDestination;

    *pDestination |= ulValue;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic AND
 *
 * @brief Performs an atomic AND operation on the specified values.
 *
 * @param [in, out] pDestination  Pointer to memory location from where value is
 *                              to be loaded and written back to.
 * @param [in] ulValue          Value to be ANDed with *pDestination.
 *
 * @return The original value of *pDestination.
 */
static portFORCE_INLINE uint32_t Atomic_AND_u32(
    uint32_t volatile *pDestination,
    uint32_t ulValue)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pDestination;

    *pDestination &= ulValue;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic NAND
 *
 * @brief Performs an atomic NAND operation on the specified values.
 *
 * @param [in, out] pDestination  Pointer to memory location from where value is
 *                              to be loaded and written back to.
 * @param [in] ulValue          Value to be NANDed with *pDestination.
 *
 * @return The original value of *pDestination.
 */
static portFORCE_INLINE uint32_t Atomic_NAND_u32(
    uint32_t volatile *pDestination,
    uint32_t ulValue)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pDestination;

    *pDestination = ~(ulCurrent & ulValue);

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

/**
 * Atomic XOR
 *
 * @brief Performs an atomic XOR operation on the specified values.
 *
 * @param [in, out] pDestination  Pointer to memory location from where value is
 *                              to be loaded and written back to.
 * @param [in] ulValue          Value to be XORed with *pDestination.
 *
 * @return The original value of *pDestination.
 */
static portFORCE_INLINE uint32_t Atomic_XOR_u32(
    uint32_t volatile *pDestination,
    uint32_t ulValue)
{
    uint32_t ulCurrent;

    ATOMIC_ENTER_CRITICAL();

    ulCurrent = *pDestination;

    *pDestination ^= ulValue;

    ATOMIC_EXIT_CRITICAL();

    return ulCurrent;
}

#ifdef __cplusplus
}
#endif

#endif /* ATOMIC_H */