/*
 *  Copyright (C) 2016-2017 Espressif Shanghai PTE LTD
 *  Copyright (C) 2015 Real Time Engineers Ltd.
 *
 *  All rights reserved
 *
 *  FreeRTOS is free software; you can redistribute it and/or modify it under
 *  the terms of the GNU General Public License (version 2) as published by the
 *  Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
 *
 ***************************************************************************
 *  >>!   NOTE: The modification to the GPL is included to allow you to     !<<
 *  >>!   distribute a combined work that includes FreeRTOS without being   !<<
 *  >>!   obliged to provide the source code for proprietary components     !<<
 *  >>!   outside of the FreeRTOS kernel.                                   !<<
 ***************************************************************************
 *
 *  FreeRTOS 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.  Full license text is available on the following
 *  link: http://www.freertos.org/a00114.html
 */


/*
 * Warning: funky preprocessor hackery ahead. Including these headers will generate two
 * functions, which names are defined by the preprocessor macros
 * PORTMUX_AQUIRE_MUX_FN_NAME and PORTMUX_RELEASE_MUX_FN_NAME. In order to do the compare
 * and exchange function, they will use whatever PORTMUX_COMPARE_SET_FN_NAME resolves to.
 *
 * In some scenarios, this header is included *twice* in portmux_impl.h: one time
 * for the 'normal' mux code which uses a compare&exchange routine, another time
 * to generate code for a second set of these routines that use a second mux
 * (in internal ram) to fake a compare&exchange on a variable in external memory.
 */



static inline bool __attribute__( ( always_inline ) )
#ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
    PORTMUX_AQUIRE_MUX_FN_NAME( portMUX_TYPE * mux,
                                int timeout_cycles,
                                const char * fnName,
                                int line )
    {
#else
    PORTMUX_AQUIRE_MUX_FN_NAME( portMUX_TYPE * mux, int timeout_cycles )
    {
        #endif


        #if !CONFIG_FREERTOS_UNICORE
            uint32_t      res;
            portBASE_TYPE coreID, otherCoreID;
            uint32_t      ccount_start;
            bool          set_timeout = timeout_cycles > portMUX_NO_TIMEOUT;
            #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                if( !set_timeout )
                {
                    timeout_cycles = 10000; /* Always set a timeout in debug mode */
                    set_timeout    = true;
                }
            #endif

            if( set_timeout ) /* Timeout */
            {
                RSR( CCOUNT, ccount_start );
            }

            #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                uint32_t owner        = mux->owner;

                if( ( owner != portMUX_FREE_VAL ) && ( owner != CORE_ID_PRO ) && ( owner != CORE_ID_APP ) )
                {
                    ets_printf( "ERROR: vPortCPUAcquireMutex: mux %p is uninitialized (0x%X)! Called from %s line %d.\n", mux, owner, fnName, line );
                    mux->owner = portMUX_FREE_VAL;
                }
            #endif

            /* Spin until we own the core */

            RSR( PRID, coreID );

            /* Note: coreID is the full 32 bit core ID (CORE_ID_PRO/CORE_ID_APP),
             * not the 0/1 value returned by xPortGetCoreID()
             */
            otherCoreID = CORE_ID_XOR_SWAP ^ coreID;

            do
            {
                /* mux->owner should be one of portMUX_FREE_VAL, CORE_ID_PRO,
                 * CORE_ID_APP:
                 *
                 * - If portMUX_FREE_VAL, we want to atomically set to 'coreID'.
                 * - If "our" coreID, we can drop through immediately.
                 * - If "otherCoreID", we spin here.
                 */
                res = coreID;
                PORTMUX_COMPARE_SET_FN_NAME( &mux->owner, portMUX_FREE_VAL, &res );

                if( res != otherCoreID )
                {
                    break; /* mux->owner is "our" coreID */
                }

                if( set_timeout )
                {
                    uint32_t ccount_now;
                    RSR( CCOUNT, ccount_now );

                    if( ccount_now - ccount_start > ( unsigned ) timeout_cycles )
                    {
                        #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                            ets_printf( "Timeout on mux! last non-recursive lock %s line %d, curr %s line %d\n", mux->lastLockedFn, mux->lastLockedLine, fnName, line );
                            ets_printf( "Owner 0x%x count %d\n", mux->owner, mux->count );
                        #endif
                        return false;
                    }
                }
            } while( 1 );

            assert( res == coreID || res == portMUX_FREE_VAL );           /* any other value implies memory corruption or uninitialized mux */
            assert( ( res == portMUX_FREE_VAL ) == ( mux->count == 0 ) ); /* we're first to lock iff count is zero */
            assert( mux->count < 0xFF );                                  /* Bad count value implies memory corruption */

            /* now we own it, we can increment the refcount */
            mux->count++;


            #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                if( res == portMUX_FREE_VAL ) /*initial lock */
                {
                    mux->lastLockedFn   = fnName;
                    mux->lastLockedLine = line;
                }
                else
                {
                    ets_printf( "Recursive lock: count=%d last non-recursive lock %s line %d, curr %s line %d\n", mux->count - 1,
                                mux->lastLockedFn, mux->lastLockedLine, fnName, line );
                }
            #endif /* CONFIG_FREERTOS_PORTMUX_DEBUG */
        #endif /* CONFIG_FREERTOS_UNICORE */
        return true;
    }

#ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
        static inline void PORTMUX_RELEASE_MUX_FN_NAME( portMUX_TYPE * mux,
                                                        const char * fnName,
                                                        int line )
        {
#else
        static inline void PORTMUX_RELEASE_MUX_FN_NAME( portMUX_TYPE * mux )
        {
            #endif


            #if !CONFIG_FREERTOS_UNICORE
                portBASE_TYPE    coreID;
                #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                    const char * lastLockedFn   = mux->lastLockedFn;
                    int          lastLockedLine = mux->lastLockedLine;
                    mux->lastLockedFn   = fnName;
                    mux->lastLockedLine = line;
                    uint32_t     owner          = mux->owner;

                    if( ( owner != portMUX_FREE_VAL ) && ( owner != CORE_ID_PRO ) && ( owner != CORE_ID_APP ) )
                    {
                        ets_printf( "ERROR: vPortCPUReleaseMutex: mux %p is invalid (0x%x)!\n", mux, mux->owner );
                    }
                #endif /* ifdef CONFIG_FREERTOS_PORTMUX_DEBUG */

                #if CONFIG_FREERTOS_PORTMUX_DEBUG || !defined( NDEBUG )
                    RSR( PRID, coreID );
                #endif

                #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG
                    if( coreID != mux->owner )
                    {
                        ets_printf( "ERROR: vPortCPUReleaseMutex: mux %p was already unlocked!\n", mux );
                        ets_printf( "Last non-recursive unlock %s line %d, curr unlock %s line %d\n", lastLockedFn, lastLockedLine, fnName, line );
                    }
                #endif

                assert( coreID == mux->owner ); /* This is a mutex we didn't lock, or it's corrupt */

                mux->count--;

                if( mux->count == 0 )
                {
                    mux->owner = portMUX_FREE_VAL;
                }
                else
                {
                    assert( mux->count < 0x100 ); /* Indicates memory corruption */
                    #ifdef CONFIG_FREERTOS_PORTMUX_DEBUG_RECURSIVE
                        ets_printf( "Recursive unlock: count=%d last locked %s line %d, curr %s line %d\n", mux->count, lastLockedFn, lastLockedLine, fnName, line );
                    #endif
                }
            #endif //!CONFIG_FREERTOS_UNICORE
        }