/*
 * 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!
 */

/*
    Changes from V4.2.1

    + Introduced the configKERNEL_INTERRUPT_PRIORITY definition.
*/

/*-----------------------------------------------------------
 * Implementation of functions defined in portable.h for the PIC24 port.
 *----------------------------------------------------------*/

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

/* Hardware specifics. */
#define portBIT_SET 1
#define portTIMER_PRESCALE 8
#define portINITIAL_SR  0

/* Defined for backward compatability with project created prior to
FreeRTOS.org V4.3.0. */
#ifndef configKERNEL_INTERRUPT_PRIORITY
    #define configKERNEL_INTERRUPT_PRIORITY 1
#endif

/* Use _T1Interrupt as the interrupt handler name if the application writer has
not provided their own. */
#ifndef configTICK_INTERRUPT_HANDLER
    #define configTICK_INTERRUPT_HANDLER _T1Interrupt
#endif /* configTICK_INTERRUPT_HANDLER */

/* The program counter is only 23 bits. */
#define portUNUSED_PR_BITS  0x7f

/* Records the nesting depth of calls to portENTER_CRITICAL(). */
UBaseType_t uxCriticalNesting = 0xef;

#if configKERNEL_INTERRUPT_PRIORITY != 1
    #error If configKERNEL_INTERRUPT_PRIORITY is not 1 then the #32 in the following macros needs changing to equal the portINTERRUPT_BITS value, which is ( configKERNEL_INTERRUPT_PRIORITY << 5 )
#endif

#if defined( __PIC24E__ ) || defined ( __PIC24F__ ) || defined( __PIC24FK__ ) || defined( __PIC24H__ )

#ifdef __HAS_EDS__
#define portRESTORE_CONTEXT()                                                                                       \
    asm volatile(   "MOV	_pxCurrentTCB, W0		\n" /* Restore the stack pointer for the task. */       \
                    "MOV	[W0], W15				\n"                                                               \
                    "POP	W0						\n"    /* Restore the critical nesting counter for the task. */    \
                    "MOV	W0, _uxCriticalNesting	\n"                                                             \
                    "POP	DSWPAG					\n"                                                             \
                    "POP    DSRPAG					\n"                                                              \
                    "POP	CORCON					\n"                                                             \
                    "POP	TBLPAG					\n"                                                             \
                    "POP	RCOUNT					\n" /* Restore the registers from the stack. */                 \
                    "POP	W14						\n"                                                               \
                    "POP.D	W12						\n"                                                             \
                    "POP.D	W10						\n"                                                             \
                    "POP.D	W8						\n"                                                              \
                    "POP.D	W6						\n"                                                              \
                    "POP.D	W4						\n"                                                              \
                    "POP.D	W2						\n"                                                              \
                    "POP.D	W0						\n"                                                              \
                    "POP	SR						  " );
#else /* __HAS_EDS__ */
#define portRESTORE_CONTEXT()                                                                                       \
    asm volatile(   "MOV	_pxCurrentTCB, W0		\n" /* Restore the stack pointer for the task. */               \
                    "MOV	[W0], W15				\n"                                                               \
                    "POP	W0						\n"    /* Restore the critical nesting counter for the task. */    \
                    "MOV	W0, _uxCriticalNesting	\n"                                                             \
                    "POP	PSVPAG					\n"                                                             \
                    "POP	CORCON					\n"                                                             \
                    "POP	TBLPAG					\n"                                                             \
                    "POP	RCOUNT					\n" /* Restore the registers from the stack. */                 \
                    "POP	W14						\n"                                                               \
                    "POP.D	W12						\n"                                                             \
                    "POP.D	W10						\n"                                                             \
                    "POP.D	W8						\n"                                                              \
                    "POP.D	W6						\n"                                                              \
                    "POP.D	W4						\n"                                                              \
                    "POP.D	W2						\n"                                                              \
                    "POP.D	W0						\n"                                                              \
                    "POP	SR						  " );
#endif /* __HAS_EDS__ */
#endif /* MPLAB_PIC24_PORT */

#if defined( __dsPIC30F__ ) || defined( __dsPIC33F__ )

#define portRESTORE_CONTEXT()                                                                                       \
    asm volatile(   "MOV	_pxCurrentTCB, W0		\n" /* Restore the stack pointer for the task. */               \
                    "MOV	[W0], W15				\n"                                                               \
                    "POP	W0						\n"    /* Restore the critical nesting counter for the task. */    \
                    "MOV	W0, _uxCriticalNesting	\n"                                                             \
                    "POP	PSVPAG					\n"                                                             \
                    "POP	CORCON					\n"                                                             \
                    "POP	DOENDH					\n"                                                             \
                    "POP	DOENDL					\n"                                                             \
                    "POP	DOSTARTH				\n"                                                                \
                    "POP	DOSTARTL				\n"                                                                \
                    "POP	DCOUNT					\n"                                                             \
                    "POP	ACCBU					\n"                                                              \
                    "POP	ACCBH					\n"                                                              \
                    "POP	ACCBL					\n"                                                              \
                    "POP	ACCAU					\n"                                                              \
                    "POP	ACCAH					\n"                                                              \
                    "POP	ACCAL					\n"                                                              \
                    "POP	TBLPAG					\n"                                                             \
                    "POP	RCOUNT					\n" /* Restore the registers from the stack. */                 \
                    "POP	W14						\n"                                                               \
                    "POP.D	W12						\n"                                                             \
                    "POP.D	W10						\n"                                                             \
                    "POP.D	W8						\n"                                                              \
                    "POP.D	W6						\n"                                                              \
                    "POP.D	W4						\n"                                                              \
                    "POP.D	W2						\n"                                                              \
                    "POP.D	W0						\n"                                                              \
                    "POP	SR						  " );

#endif /* MPLAB_DSPIC_PORT */

#ifndef portRESTORE_CONTEXT
    #error Unrecognised device selected

    /* Note:  dsPIC parts with EDS are not supported as there is no easy way to
    recover the hardware stacked copies for DOCOUNT, DOHIGH, DOLOW. */
#endif

/*
 * Setup the timer used to generate the tick interrupt.
 */
void vApplicationSetupTickTimerInterrupt(void);

/*
 * See header file for description.
 */
StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
{
    uint16_t usCode;
    UBaseType_t i;

    const StackType_t xInitialStack[] =
    {
        0x1111, /* W1 */
        0x2222, /* W2 */
        0x3333, /* W3 */
        0x4444, /* W4 */
        0x5555, /* W5 */
        0x6666, /* W6 */
        0x7777, /* W7 */
        0x8888, /* W8 */
        0x9999, /* W9 */
        0xaaaa, /* W10 */
        0xbbbb, /* W11 */
        0xcccc, /* W12 */
        0xdddd, /* W13 */
        0xeeee, /* W14 */
        0xcdce, /* RCOUNT */
        0xabac, /* TBLPAG */

        /* dsPIC specific registers. */
#ifdef MPLAB_DSPIC_PORT
        0x0202, /* ACCAL */
        0x0303, /* ACCAH */
        0x0404, /* ACCAU */
        0x0505, /* ACCBL */
        0x0606, /* ACCBH */
        0x0707, /* ACCBU */
        0x0808, /* DCOUNT */
        0x090a, /* DOSTARTL */
        0x1010, /* DOSTARTH */
        0x1110, /* DOENDL */
        0x1212, /* DOENDH */
#endif
    };

    /* Setup the stack as if a yield had occurred.

    Save the low bytes of the program counter. */
    usCode = (uint16_t) pxCode;
    *pxTopOfStack = (StackType_t) usCode;
    pxTopOfStack++;

    /* Save the high byte of the program counter.  This will always be zero
    here as it is passed in a 16bit pointer.  If the address is greater than
    16 bits then the pointer will point to a jump table. */
    *pxTopOfStack = (StackType_t) 0;
    pxTopOfStack++;

    /* Status register with interrupts enabled. */
    *pxTopOfStack = portINITIAL_SR;
    pxTopOfStack++;

    /* Parameters are passed in W0. */
    *pxTopOfStack = (StackType_t) pvParameters;
    pxTopOfStack++;

    for (i = 0; i < (sizeof(xInitialStack) / sizeof(StackType_t)); i++)
    {
        *pxTopOfStack = xInitialStack[ i ];
        pxTopOfStack++;
    }

    *pxTopOfStack = CORCON;
    pxTopOfStack++;

#if defined(__HAS_EDS__)
    *pxTopOfStack = DSRPAG;
    pxTopOfStack++;
    *pxTopOfStack = DSWPAG;
    pxTopOfStack++;
#else /* __HAS_EDS__ */
    *pxTopOfStack = PSVPAG;
    pxTopOfStack++;
#endif /* __HAS_EDS__ */

    /* Finally the critical nesting depth. */
    *pxTopOfStack = 0x00;
    pxTopOfStack++;

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

BaseType_t xPortStartScheduler(void)
{
    /* Setup a timer for the tick ISR. */
    vApplicationSetupTickTimerInterrupt();

    /* Restore the context of the first task to run. */
    portRESTORE_CONTEXT();

    /* Simulate the end of the yield function. */
    asm volatile("return");

    /* Should not reach here. */
    return pdTRUE;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler(void)
{
    /* Not implemented in ports where there is nothing to return to.
    Artificially force an assert. */
    configASSERT(uxCriticalNesting == 1000UL);
}
/*-----------------------------------------------------------*/

/*
 * Setup a timer for a regular tick.
 */
__attribute__((weak)) void vApplicationSetupTickTimerInterrupt(void)
{
    const uint32_t ulCompareMatch = ((configCPU_CLOCK_HZ / portTIMER_PRESCALE) / configTICK_RATE_HZ) - 1;

    /* Prescale of 8. */
    T1CON = 0;
    TMR1 = 0;

    PR1 = (uint16_t) ulCompareMatch;

    /* Setup timer 1 interrupt priority. */
    IPC0bits.T1IP = configKERNEL_INTERRUPT_PRIORITY;

    /* Clear the interrupt as a starting condition. */
    IFS0bits.T1IF = 0;

    /* Enable the interrupt. */
    IEC0bits.T1IE = 1;

    /* Setup the prescale value. */
    T1CONbits.TCKPS0 = 1;
    T1CONbits.TCKPS1 = 0;

    /* Start the timer. */
    T1CONbits.TON = 1;
}
/*-----------------------------------------------------------*/

void vPortEnterCritical(void)
{
    portDISABLE_INTERRUPTS();
    uxCriticalNesting++;
}
/*-----------------------------------------------------------*/

void vPortExitCritical(void)
{
    configASSERT(uxCriticalNesting);
    uxCriticalNesting--;

    if (uxCriticalNesting == 0)
    {
        portENABLE_INTERRUPTS();
    }
}
/*-----------------------------------------------------------*/

void __attribute__((__interrupt__, auto_psv)) configTICK_INTERRUPT_HANDLER(void)
{
    /* Clear the timer interrupt. */
    IFS0bits.T1IF = 0;

    if (xTaskIncrementTick() != pdFALSE)
    {
        portYIELD();
    }
}

