/*
 * 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
 */

#include "FreeRTOS.h"
#include "task.h"
#include "FreeRTOSConfig.h"

#include "arc/arc_exception.h"
#include "arc/arc_timer.h"
#include "board.h"

#include "arc_freertos_exceptions.h"

volatile unsigned int ulCriticalNesting = 999UL;
volatile unsigned int context_switch_reqflg;	/* task context switch request flag in exceptions and interrupts handling */

/* --------------------------------------------------------------------------*/
/**
 * @brief kernel tick interrupt handler of freertos
 */
/* ----------------------------------------------------------------------------*/
static void vKernelTick( void *ptr )
{
	/* clear timer interrupt */
	timer_int_clear(BOARD_OS_TIMER_ID);
	board_timer_update(configTICK_RATE_HZ);

	if (xTaskIncrementTick()) {
		portYIELD_FROM_ISR();	/* need to make task switch */
	}
}

/* --------------------------------------------------------------------------*/
/**
 * @brief  setup freertos kernel tick
 */
/* ----------------------------------------------------------------------------*/
static void prvSetupTimerInterrupt(void)
{
	unsigned int cyc = configCPU_CLOCK_HZ / configTICK_RATE_HZ;

	int_disable(BOARD_OS_TIMER_INTNO); /* disable os timer interrupt */
	timer_stop(BOARD_OS_TIMER_ID);
	timer_start(BOARD_OS_TIMER_ID, TIMER_CTRL_IE | TIMER_CTRL_NH, cyc);

	int_handler_install(BOARD_OS_TIMER_INTNO, (INT_HANDLER_T)vKernelTick);
	int_pri_set(BOARD_OS_TIMER_INTNO, INT_PRI_MIN);
	int_enable(BOARD_OS_TIMER_INTNO);
}

/*
 * Setup the stack of a new task so it is ready to be placed under the
 * scheduler control.  The registers have to be placed on the stack in
 * the order that the port expects to find them.
 *
 * For ARC, task context switch is implemented with the help of SWI exception
 * It's not efficient but simple.
 *
 */
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
	/* To ensure asserts in tasks.c don't fail, although in this case the assert
	is not really required. */
	pxTopOfStack--;

	/* Setup the initial stack of the task.  The stack is set exactly as
	expected by the portRESTORE_CONTEXT() macro. */

	/* When the task starts is will expect to find the function parameter in
	R0. */
	*pxTopOfStack = ( StackType_t ) pvParameters;	/* R0 */

	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) pxCode;		/* function body */

	/* PC */
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) start_r;	/* dispatch return address */

	pxTopOfStack--;
	*pxTopOfStack = (StackType_t) portNO_CRITICAL_NESTING;
	return pxTopOfStack;
}

/* --------------------------------------------------------------------------*/
/**
 * @brief  start the freertos scheduler, go to the first task
 *
 * @returns
 */
/* ----------------------------------------------------------------------------*/
BaseType_t xPortStartScheduler( void )
{
	/* Start the timer that generates the tick ISR. */
	prvSetupTimerInterrupt();
	start_dispatch();

	/* Should not get here! */
	return 0;
}

/* --------------------------------------------------------------------------*/
/**
 * @brief
 */
/* ----------------------------------------------------------------------------*/
void vPortEndScheduler( void )
{

}

/* --------------------------------------------------------------------------*/
/**
 * @brief  generate a task switch request in ISR
 */
/* ----------------------------------------------------------------------------*/
void vPortYieldFromIsr(void)
{
	unsigned int status32;

	status32 = cpu_lock_save();
	context_switch_reqflg = true;
	cpu_unlock_restore(status32);
}

/* --------------------------------------------------------------------------*/
/**
 * @brief
 */
/* ----------------------------------------------------------------------------*/
void vPortYield(void)
{
	unsigned int status32;

	status32 = cpu_lock_save();
	dispatch();
	cpu_unlock_restore(status32);
}

/* --------------------------------------------------------------------------*/
/**
 * @brief
 */
/* ----------------------------------------------------------------------------*/
void vPortEndTask(void)
{

#if ( INCLUDE_vTaskDelete == 1 )
	vTaskDelete(NULL); /* Delete task itself */
#endif

	while(1) { /* Yield to other task */
		vPortYield();
	}
}

#if ARC_FEATURE_STACK_CHECK

/*
 * !!! Note !!!
 * This a trick!!!
 * It's a copy from task.c. We need to konw the definition of TCB for the purpose of hardware
 * stack check. Pls don't forget to update it when FreeRTOS is updated.
 */
typedef struct tskTaskControlBlock /* The old naming convention is used to prevent breaking kernel aware debuggers. */
{
	volatile StackType_t	*pxTopOfStack;	/*< Points to the location of the last item placed on the tasks stack.  THIS MUST BE THE FIRST MEMBER OF THE TCB STRUCT. */

	#if ( portUSING_MPU_WRAPPERS == 1 )
		xMPU_SETTINGS	xMPUSettings;		/*< The MPU settings are defined as part of the port layer.  THIS MUST BE THE SECOND MEMBER OF THE TCB STRUCT. */
	#endif

	ListItem_t			xStateListItem;	/*< The list that the state list item of a task is reference from denotes the state of that task (Ready, Blocked, Suspended ). */
	ListItem_t			xEventListItem;		/*< Used to reference a task from an event list. */
	UBaseType_t			uxPriority;			/*< The priority of the task.  0 is the lowest priority. */
	StackType_t			*pxStack;			/*< Points to the start of the stack. */
	char				pcTaskName[ configMAX_TASK_NAME_LEN ];/*< Descriptive name given to the task when created.  Facilitates debugging only. */ /*lint !e971 Unqualified char types are allowed for strings and single characters only. */

	#if ( ( portSTACK_GROWTH > 0 ) || ( configRECORD_STACK_HIGH_ADDRESS == 1 ) )
		StackType_t		*pxEndOfStack;		/*< Points to the highest valid address for the stack. */
	#endif

	#if ( portCRITICAL_NESTING_IN_TCB == 1 )
		UBaseType_t		uxCriticalNesting;	/*< Holds the critical section nesting depth for ports that do not maintain their own count in the port layer. */
	#endif

	#if ( configUSE_TRACE_FACILITY == 1 )
		UBaseType_t		uxTCBNumber;		/*< Stores a number that increments each time a TCB is created.  It allows debuggers to determine when a task has been deleted and then recreated. */
		UBaseType_t		uxTaskNumber;		/*< Stores a number specifically for use by third party trace code. */
	#endif

	#if ( configUSE_MUTEXES == 1 )
		UBaseType_t		uxBasePriority;		/*< The priority last assigned to the task - used by the priority inheritance mechanism. */
		UBaseType_t		uxMutexesHeld;
	#endif

	#if ( configUSE_APPLICATION_TASK_TAG == 1 )
		TaskHookFunction_t pxTaskTag;
	#endif

	#if( configNUM_THREAD_LOCAL_STORAGE_POINTERS > 0 )
		void			*pvThreadLocalStoragePointers[ configNUM_THREAD_LOCAL_STORAGE_POINTERS ];
	#endif

	#if( configGENERATE_RUN_TIME_STATS == 1 )
		uint32_t		ulRunTimeCounter;	/*< Stores the amount of time the task has spent in the Running state. */
	#endif

	#if ( configUSE_NEWLIB_REENTRANT == 1 )
		/* Allocate a Newlib reent structure that is specific to this task.
		Note Newlib support has been included by popular demand, but is not
		used by the FreeRTOS maintainers themselves.  FreeRTOS is not
		responsible for resulting newlib operation.  User must be familiar with
		newlib and must provide system-wide implementations of the necessary
		stubs. Be warned that (at the time of writing) the current newlib design
		implements a system-wide malloc() that must be provided with locks. */
		struct	_reent xNewLib_reent;
	#endif

	#if( configUSE_TASK_NOTIFICATIONS == 1 )
		volatile uint32_t ulNotifiedValue;
		volatile uint8_t ucNotifyState;
	#endif

	/* See the comments above the definition of
	tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE. */
	#if( tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE != 0 ) /*lint !e731 !e9029 Macro has been consolidated for readability reasons. */
		uint8_t	ucStaticallyAllocated; 		/*< Set to pdTRUE if the task is a statically allocated to ensure no attempt is made to free the memory. */
	#endif

	#if( INCLUDE_xTaskAbortDelay == 1 )
		uint8_t ucDelayAborted;
	#endif

	#if( configUSE_POSIX_ERRNO == 1 )
		int iTaskErrno;
	#endif

} tskTCB;


void vPortSetStackCheck(TaskHandle_t old, TaskHandle_t new)
{

	if (new != NULL) {
#if ARC_FEATURE_SEC_PRESENT
		arc_aux_write(AUX_S_KSTACK_BASE, (uint32_t)(new->pxEndOfStack));
		arc_aux_write(AUX_S_KSTACK_TOP, (uint32_t)(new->pxStack));
#else
		arc_aux_write(AUX_KSTACK_BASE, (uint32_t)(new->pxEndOfStack));
		arc_aux_write(AUX_KSTACK_TOP, (uint32_t)(new->pxStack));
#endif
	}
}
#endif