/*
 * 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!
 */

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for the PPC405 port.
 *----------------------------------------------------------*/


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

/* Library includes. */
#include "xtime_l.h"
#include "xintc.h"
#include "xintc_i.h"

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

/* Definitions to set the initial MSR of each task. */
#define portCRITICAL_INTERRUPT_ENABLE   ( 1UL << 17UL )
#define portEXTERNAL_INTERRUPT_ENABLE   ( 1UL << 15UL )
#define portMACHINE_CHECK_ENABLE        ( 1UL << 12UL )

#if configUSE_FPU == 1
    #define portAPU_PRESENT             ( 1UL << 25UL )
    #define portFCM_FPU_PRESENT         ( 1UL << 13UL )
#else
    #define portAPU_PRESENT             ( 0UL )
    #define portFCM_FPU_PRESENT         ( 0UL )
#endif

#define portINITIAL_MSR     ( portCRITICAL_INTERRUPT_ENABLE | portEXTERNAL_INTERRUPT_ENABLE | portMACHINE_CHECK_ENABLE | portAPU_PRESENT | portFCM_FPU_PRESENT )


extern const unsigned _SDA_BASE_;
extern const unsigned _SDA2_BASE_;

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

/*
 * Setup the system timer to generate the tick interrupt.
 */
static void prvSetupTimerInterrupt(void);

/*
 * The handler for the tick interrupt - defined in portasm.s.
 */
extern void vPortTickISR(void);

/*
 * The handler for the yield function - defined in portasm.s.
 */
extern void vPortYield(void);

/*
 * Function to start the scheduler running by starting the highest
 * priority task that has thus far been created.
 */
extern void vPortStartFirstTask(void);

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

/* Structure used to hold the state of the interrupt controller. */
static XIntc xInterruptController;

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

/*
 * Initialise the stack of a task to look exactly as if the task had been
 * interrupted.
 *
 * See the header file portable.h.
 */
StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
{
    /* Place a known value at the bottom of the stack for debugging. */
    *pxTopOfStack = 0xDEADBEEF;
    pxTopOfStack--;

    /* EABI stack frame. */
    pxTopOfStack -= 20; /* Previous backchain and LR, R31 to R4 inclusive. */

    /* Parameters in R13. */
    *pxTopOfStack = (StackType_t) &_SDA_BASE_;   /* address of the first small data area */
    pxTopOfStack -= 10;

    /* Parameters in R3. */
    *pxTopOfStack = (StackType_t) pvParameters;
    pxTopOfStack--;

    /* Parameters in R2. */
    *pxTopOfStack = (StackType_t) &_SDA2_BASE_;      /* address of the second small data area */
    pxTopOfStack--;

    /* R1 is the stack pointer so is omitted. */

    *pxTopOfStack = 0x10000001UL;;  /* R0. */
    pxTopOfStack--;
    *pxTopOfStack = 0x00000000UL;   /* USPRG0. */
    pxTopOfStack--;
    *pxTopOfStack = 0x00000000UL;   /* CR. */
    pxTopOfStack--;
    *pxTopOfStack = 0x00000000UL;   /* XER. */
    pxTopOfStack--;
    *pxTopOfStack = 0x00000000UL;   /* CTR. */
    pxTopOfStack--;
    *pxTopOfStack = (StackType_t) vPortEndScheduler;     /* LR. */
    pxTopOfStack--;
    *pxTopOfStack = (StackType_t) pxCode;   /* SRR0. */
    pxTopOfStack--;
    *pxTopOfStack = portINITIAL_MSR;/* SRR1. */
    pxTopOfStack--;
    *pxTopOfStack = (StackType_t) vPortEndScheduler;  /* Next LR. */
    pxTopOfStack--;
    *pxTopOfStack = 0x00000000UL;/* Backchain. */

    return pxTopOfStack;
}
/*-----------------------------------------------------------*/

BaseType_t xPortStartScheduler(void)
{
    prvSetupTimerInterrupt();
    XExc_RegisterHandler(XEXC_ID_SYSTEM_CALL, (XExceptionHandler) vPortYield, (void *) 0);
    vPortStartFirstTask();

    /* Should not get here as the tasks are now running! */
    return pdFALSE;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler(void)
{
    /* Not implemented. */
    for (;;);
}
/*-----------------------------------------------------------*/

/*
 * Hardware initialisation to generate the RTOS tick.
 */
static void prvSetupTimerInterrupt(void)
{
    const uint32_t ulInterval = ((configCPU_CLOCK_HZ / configTICK_RATE_HZ) - 1UL);

    XTime_PITClearInterrupt();
    XTime_FITClearInterrupt();
    XTime_WDTClearInterrupt();
    XTime_WDTDisableInterrupt();
    XTime_FITDisableInterrupt();

    XExc_RegisterHandler(XEXC_ID_PIT_INT, (XExceptionHandler) vPortTickISR, (void *) 0);

    XTime_PITEnableAutoReload();
    XTime_PITSetInterval(ulInterval);
    XTime_PITEnableInterrupt();
}
/*-----------------------------------------------------------*/

void vPortISRHandler(void *pvNullDoNotUse)
{
    uint32_t ulInterruptStatus, ulInterruptMask = 1UL;
    BaseType_t xInterruptNumber;
    XIntc_Config *pxInterruptController;
    XIntc_VectorTableEntry *pxTable;

    /* Just to remove compiler warning. */
    (void) pvNullDoNotUse;

    /* Get the configuration by using the device ID - in this case it is
    assumed that only one interrupt controller is being used. */
    pxInterruptController = &XIntc_ConfigTable[ XPAR_XPS_INTC_0_DEVICE_ID ];

    /* Which interrupts are pending? */
    ulInterruptStatus = XIntc_mGetIntrStatus(pxInterruptController->BaseAddress);

    for (xInterruptNumber = 0; xInterruptNumber < XPAR_INTC_MAX_NUM_INTR_INPUTS; xInterruptNumber++)
    {
        if (ulInterruptStatus & 0x01UL)
        {
            /* Clear the pending interrupt. */
            XIntc_mAckIntr(pxInterruptController->BaseAddress, ulInterruptMask);

            /* Call the registered handler. */
            pxTable = &(pxInterruptController->HandlerTable[ xInterruptNumber ]);
            pxTable->Handler(pxTable->CallBackRef);
        }

        /* Check the next interrupt. */
        ulInterruptMask <<= 0x01UL;
        ulInterruptStatus >>= 0x01UL;

        /* Have we serviced all interrupts? */
        if (ulInterruptStatus == 0UL)
        {
            break;
        }
    }
}
/*-----------------------------------------------------------*/

void vPortSetupInterruptController(void)
{
    extern void vPortISRWrapper(void);

    /* Perform all library calls necessary to initialise the exception table
    and interrupt controller.  This assumes only one interrupt controller is in
    use. */
    XExc_mDisableExceptions(XEXC_NON_CRITICAL);
    XExc_Init();

    /* The library functions save the context - we then jump to a wrapper to
    save the stack into the TCB.  The wrapper then calls the handler defined
    above. */
    XExc_RegisterHandler(XEXC_ID_NON_CRITICAL_INT, (XExceptionHandler) vPortISRWrapper, NULL);
    XIntc_Initialize(&xInterruptController, XPAR_XPS_INTC_0_DEVICE_ID);
    XIntc_Start(&xInterruptController, XIN_REAL_MODE);
}
/*-----------------------------------------------------------*/

BaseType_t xPortInstallInterruptHandler(uint8_t ucInterruptID, XInterruptHandler pxHandler, void *pvCallBackRef)
{
    BaseType_t xReturn = pdFAIL;

    /* This function is defined here so the scope of xInterruptController can
    remain within this file. */

    if (XST_SUCCESS == XIntc_Connect(&xInterruptController, ucInterruptID, pxHandler, pvCallBackRef))
    {
        XIntc_Enable(&xInterruptController, ucInterruptID);
        xReturn = pdPASS;
    }

    return xReturn;
}
