/*
 * FreeRTOS Kernel <DEVELOPMENT BRANCH>
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * SPDX-License-Identifier: MIT
 *
 * 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.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"

/* Hardware includes. */
#include <microblaze_exceptions_i.h>
#include <microblaze_exceptions_g.h>

/* The Xilinx library defined exception entry point stacks a number of
 * registers.  These definitions are offsets from the stack pointer to the various
 * stacked register values. */
#define portexR3_STACK_OFFSET                 4
#define portexR4_STACK_OFFSET                 5
#define portexR5_STACK_OFFSET                 6
#define portexR6_STACK_OFFSET                 7
#define portexR7_STACK_OFFSET                 8
#define portexR8_STACK_OFFSET                 9
#define portexR9_STACK_OFFSET                 10
#define portexR10_STACK_OFFSET                11
#define portexR11_STACK_OFFSET                12
#define portexR12_STACK_OFFSET                13
#define portexR15_STACK_OFFSET                16
#define portexR18_STACK_OFFSET                19
#define portexMSR_STACK_OFFSET                20
#define portexR19_STACK_OFFSET                -1

/* This is defined to equal the size, in bytes, of the stack frame generated by
 * the Xilinx standard library exception entry point.  It is required to determine
 * the stack pointer value prior to the exception being entered. */
#define portexASM_HANDLER_STACK_FRAME_SIZE    84UL

/* The number of bytes a MicroBlaze instruction consumes. */
#define portexINSTRUCTION_SIZE                4

/* Exclude this entire file if the MicroBlaze is not configured to handle
 * exceptions, or the application defined configuration constant
 * configINSTALL_EXCEPTION_HANDLERS is not set to 1. */
#if ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 )

/* This variable is set in the exception entry code, before
 * vPortExceptionHandler is called. */
    uint32_t * pulStackPointerOnFunctionEntry = NULL;

/* This is the structure that is filled with the MicroBlaze context as it
 * existed immediately prior to the exception occurrence.  A pointer to this
 * structure is passed into the vApplicationExceptionRegisterDump() callback
 * function, if one is defined. */
    static xPortRegisterDump xRegisterDump;

/* This is the FreeRTOS exception handler that is installed for all exception
 * types.  It is called from vPortExceptionHandlerEntry() - which is itself defined
 * in portasm.S. */
    void vPortExceptionHandler( void * pvExceptionID );
    extern void vPortExceptionHandlerEntry( void * pvExceptionID );

/*-----------------------------------------------------------*/

/* vApplicationExceptionRegisterDump() is a callback function that the
 * application can optionally define to receive a populated xPortRegisterDump
 * structure.  If the application chooses not to define a version of
 * vApplicationExceptionRegisterDump() then this weekly defined default
 * implementation will be called instead. */
    extern void vApplicationExceptionRegisterDump( xPortRegisterDump * xRegisterDump ) __attribute__( ( weak ) );
    void vApplicationExceptionRegisterDump( xPortRegisterDump * xRegisterDump )
    {
        ( void ) xRegisterDump;

        for( ; ; )
        {
            portNOP();
        }
    }
/*-----------------------------------------------------------*/

    void vPortExceptionHandler( void * pvExceptionID )
    {
        extern void * pxCurrentTCB;

        /* Fill an xPortRegisterDump structure with the MicroBlaze context as it
         * was immediately before the exception occurrence. */

        /* First fill in the name and handle of the task that was in the Running
         * state when the exception occurred. */
        xRegisterDump.xCurrentTaskHandle = pxCurrentTCB;
        xRegisterDump.pcCurrentTaskName = pcTaskGetName( NULL );

        configASSERT( pulStackPointerOnFunctionEntry );

        /* Obtain the values of registers that were stacked prior to this function
         * being called, and may have changed since they were stacked. */
        xRegisterDump.ulR3 = pulStackPointerOnFunctionEntry[ portexR3_STACK_OFFSET ];
        xRegisterDump.ulR4 = pulStackPointerOnFunctionEntry[ portexR4_STACK_OFFSET ];
        xRegisterDump.ulR5 = pulStackPointerOnFunctionEntry[ portexR5_STACK_OFFSET ];
        xRegisterDump.ulR6 = pulStackPointerOnFunctionEntry[ portexR6_STACK_OFFSET ];
        xRegisterDump.ulR7 = pulStackPointerOnFunctionEntry[ portexR7_STACK_OFFSET ];
        xRegisterDump.ulR8 = pulStackPointerOnFunctionEntry[ portexR8_STACK_OFFSET ];
        xRegisterDump.ulR9 = pulStackPointerOnFunctionEntry[ portexR9_STACK_OFFSET ];
        xRegisterDump.ulR10 = pulStackPointerOnFunctionEntry[ portexR10_STACK_OFFSET ];
        xRegisterDump.ulR11 = pulStackPointerOnFunctionEntry[ portexR11_STACK_OFFSET ];
        xRegisterDump.ulR12 = pulStackPointerOnFunctionEntry[ portexR12_STACK_OFFSET ];
        xRegisterDump.ulR15_return_address_from_subroutine = pulStackPointerOnFunctionEntry[ portexR15_STACK_OFFSET ];
        xRegisterDump.ulR18 = pulStackPointerOnFunctionEntry[ portexR18_STACK_OFFSET ];
        xRegisterDump.ulR19 = pulStackPointerOnFunctionEntry[ portexR19_STACK_OFFSET ];
        xRegisterDump.ulMSR = pulStackPointerOnFunctionEntry[ portexMSR_STACK_OFFSET ];

        /* Obtain the value of all other registers. */
        xRegisterDump.ulR2_small_data_area = mfgpr( R2 );
        xRegisterDump.ulR13_read_write_small_data_area = mfgpr( R13 );
        xRegisterDump.ulR14_return_address_from_interrupt = mfgpr( R14 );
        xRegisterDump.ulR16_return_address_from_trap = mfgpr( R16 );
        xRegisterDump.ulR17_return_address_from_exceptions = mfgpr( R17 );
        xRegisterDump.ulR20 = mfgpr( R20 );
        xRegisterDump.ulR21 = mfgpr( R21 );
        xRegisterDump.ulR22 = mfgpr( R22 );
        xRegisterDump.ulR23 = mfgpr( R23 );
        xRegisterDump.ulR24 = mfgpr( R24 );
        xRegisterDump.ulR25 = mfgpr( R25 );
        xRegisterDump.ulR26 = mfgpr( R26 );
        xRegisterDump.ulR27 = mfgpr( R27 );
        xRegisterDump.ulR28 = mfgpr( R28 );
        xRegisterDump.ulR29 = mfgpr( R29 );
        xRegisterDump.ulR30 = mfgpr( R30 );
        xRegisterDump.ulR31 = mfgpr( R31 );
        xRegisterDump.ulR1_SP = ( ( uint32_t ) pulStackPointerOnFunctionEntry ) + portexASM_HANDLER_STACK_FRAME_SIZE;
        xRegisterDump.ulEAR = mfear();
        xRegisterDump.ulESR = mfesr();
        xRegisterDump.ulEDR = mfedr();

        /* Move the saved program counter back to the instruction that was executed
         * when the exception occurred.  This is only valid for certain types of
         * exception. */
        xRegisterDump.ulPC = xRegisterDump.ulR17_return_address_from_exceptions - portexINSTRUCTION_SIZE;

        #if ( XPAR_MICROBLAZE_USE_FPU != 0 )
        {
            xRegisterDump.ulFSR = mffsr();
        }
        #else
        {
            xRegisterDump.ulFSR = 0UL;
        }
        #endif

        /* Also fill in a string that describes what type of exception this is.
         * The string uses the same ID names as defined in the MicroBlaze standard
         * library exception header files. */
        switch( ( uint32_t ) pvExceptionID )
        {
            case XEXC_ID_FSL:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_FSL";
                break;

            case XEXC_ID_UNALIGNED_ACCESS:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_UNALIGNED_ACCESS";
                break;

            case XEXC_ID_ILLEGAL_OPCODE:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_ILLEGAL_OPCODE";
                break;

            case XEXC_ID_M_AXI_I_EXCEPTION:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_M_AXI_I_EXCEPTION or XEXC_ID_IPLB_EXCEPTION";
                break;

            case XEXC_ID_M_AXI_D_EXCEPTION:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_M_AXI_D_EXCEPTION or XEXC_ID_DPLB_EXCEPTION";
                break;

            case XEXC_ID_DIV_BY_ZERO:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_DIV_BY_ZERO";
                break;

            case XEXC_ID_STACK_VIOLATION:
                xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_STACK_VIOLATION or XEXC_ID_MMU";
                break;

                #if ( XPAR_MICROBLAZE_USE_FPU != 0 )
                    case XEXC_ID_FPU:
                        xRegisterDump.pcExceptionCause = ( int8_t * const ) "XEXC_ID_FPU see ulFSR value";
                        break;
                #endif /* XPAR_MICROBLAZE_USE_FPU */
        }

        /* vApplicationExceptionRegisterDump() is a callback function that the
         * application can optionally define to receive the populated xPortRegisterDump
         * structure.  If the application chooses not to define a version of
         * vApplicationExceptionRegisterDump() then the weekly defined default
         * implementation within this file will be called instead. */
        vApplicationExceptionRegisterDump( &xRegisterDump );

        /* Must not attempt to leave this function! */
        for( ; ; )
        {
            portNOP();
        }
    }
/*-----------------------------------------------------------*/

    void vPortExceptionsInstallHandlers( void )
    {
        static uint32_t ulHandlersAlreadyInstalled = pdFALSE;

        if( ulHandlersAlreadyInstalled == pdFALSE )
        {
            ulHandlersAlreadyInstalled = pdTRUE;

            #if XPAR_MICROBLAZE_UNALIGNED_EXCEPTIONS == 1
                microblaze_register_exception_handler( XEXC_ID_UNALIGNED_ACCESS, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_UNALIGNED_ACCESS );
            #endif /* XPAR_MICROBLAZE_UNALIGNED_EXCEPTIONS*/

            #if XPAR_MICROBLAZE_ILL_OPCODE_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_ILLEGAL_OPCODE, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_ILLEGAL_OPCODE );
            #endif /* XPAR_MICROBLAZE_ILL_OPCODE_EXCEPTION */

            #if XPAR_MICROBLAZE_M_AXI_I_BUS_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_M_AXI_I_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_M_AXI_I_EXCEPTION );
            #endif /* XPAR_MICROBLAZE_M_AXI_I_BUS_EXCEPTION */

            #if XPAR_MICROBLAZE_M_AXI_D_BUS_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_M_AXI_D_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_M_AXI_D_EXCEPTION );
            #endif /* XPAR_MICROBLAZE_M_AXI_D_BUS_EXCEPTION */

            #if XPAR_MICROBLAZE_IPLB_BUS_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_IPLB_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_IPLB_EXCEPTION );
            #endif /* XPAR_MICROBLAZE_IPLB_BUS_EXCEPTION */

            #if XPAR_MICROBLAZE_DPLB_BUS_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_DPLB_EXCEPTION, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_DPLB_EXCEPTION );
            #endif /* XPAR_MICROBLAZE_DPLB_BUS_EXCEPTION */

            #if XPAR_MICROBLAZE_DIV_ZERO_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_DIV_BY_ZERO, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_DIV_BY_ZERO );
            #endif /* XPAR_MICROBLAZE_DIV_ZERO_EXCEPTION */

            #if XPAR_MICROBLAZE_FPU_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_FPU, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_FPU );
            #endif /* XPAR_MICROBLAZE_FPU_EXCEPTION */

            #if XPAR_MICROBLAZE_FSL_EXCEPTION == 1
                microblaze_register_exception_handler( XEXC_ID_FSL, vPortExceptionHandlerEntry, ( void * ) XEXC_ID_FSL );
            #endif /* XPAR_MICROBLAZE_FSL_EXCEPTION */

            microblaze_enable_exceptions();
        }
    }

/* Exclude the entire file if the MicroBlaze is not configured to handle
 * exceptions, or the application defined configuration item
 * configINSTALL_EXCEPTION_HANDLERS is not set to 1. */
#endif /* ( MICROBLAZE_EXCEPTIONS_ENABLED == 1 ) && ( configINSTALL_EXCEPTION_HANDLERS == 1 ) */