/*
    FreeRTOS V9.0.0rc2 - Copyright (C) 2016 Real Time Engineers Ltd.
    All rights reserved

    VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

    This file is part of the FreeRTOS distribution.

    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

    ***************************************************************************
     *                                                                       *
     *    FreeRTOS provides completely free yet professionally developed,    *
     *    robust, strictly quality controlled, supported, and cross          *
     *    platform software that is more than just the market leader, it     *
     *    is the industry's de facto standard.                               *
     *                                                                       *
     *    Help yourself get started quickly while simultaneously helping     *
     *    to support the FreeRTOS project by purchasing a FreeRTOS           *
     *    tutorial book, reference manual, or both:                          *
     *    http://www.FreeRTOS.org/Documentation                              *
     *                                                                       *
    ***************************************************************************

    http://www.FreeRTOS.org/FAQHelp.html - Having a problem?  Start by reading
    the FAQ page "My application does not run, what could be wrong?".  Have you
    defined configASSERT()?

    http://www.FreeRTOS.org/support - In return for receiving this top quality
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    http://www.FreeRTOS.org/training - Investing in training allows your team to
    be as productive as possible as early as possible.  Now you can receive
    FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
    Ltd, and the world's leading authority on the world's leading RTOS.

    http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
    including FreeRTOS+Trace - an indispensable productivity tool, a DOS
    compatible FAT file system, and our tiny thread aware UDP/IP stack.

    http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
    Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.

    http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
    Integrity Systems ltd. to sell under the OpenRTOS brand.  Low cost OpenRTOS
    licenses offer ticketed support, indemnification and commercial middleware.

    http://www.SafeRTOS.com - High Integrity Systems also provide a safety
    engineered and independently SIL3 certified version for use in safety and
    mission critical applications that require provable dependability.

    1 tab == 4 spaces!
*/

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

/*-----------------------------------------------------------*/

/* Count of the critical section nesting depth. */
uint32_t ulCriticalNesting = 9999;

/*-----------------------------------------------------------*/

/* Registers required to configure the RTI. */
#define portRTI_GCTRL_REG  		( * ( ( volatile uint32_t * ) 0xFFFFFC00 ) )
#define portRTI_TBCTRL_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC04 ) )
#define portRTI_COMPCTRL_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC0C ) )
#define portRTI_CNT0_FRC0_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC10 ) )
#define portRTI_CNT0_UC0_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC14 ) )
#define portRTI_CNT0_CPUC0_REG  ( * ( ( volatile uint32_t * ) 0xFFFFFC18 ) )
#define portRTI_CNT0_COMP0_REG  ( * ( ( volatile uint32_t * ) 0xFFFFFC50 ) )
#define portRTI_CNT0_UDCP0_REG  ( * ( ( volatile uint32_t * ) 0xFFFFFC54 ) )
#define portRTI_SETINTENA_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC80 ) )
#define portRTI_CLEARINTENA_REG ( * ( ( volatile uint32_t * ) 0xFFFFFC84 ) )
#define portRTI_INTFLAG_REG  	( * ( ( volatile uint32_t * ) 0xFFFFFC88 ) )


/* Constants required to set up the initial stack of each task. */
#define portINITIAL_SPSR	   	( ( StackType_t ) 0x1F )
#define portINITIAL_FPSCR	  	( ( StackType_t ) 0x00 )
#define portINSTRUCTION_SIZE   	( ( StackType_t ) 0x04 )
#define portTHUMB_MODE_BIT		( ( StackType_t ) 0x20 )

/* The number of words on the stack frame between the saved Top Of Stack and
R0 (in which the parameters are passed. */
#define portSPACE_BETWEEN_TOS_AND_PARAMETERS	( 12 )

/*-----------------------------------------------------------*/

/* vPortStartFirstSTask() is defined in portASM.asm */
extern void vPortStartFirstTask( void );

/*-----------------------------------------------------------*/

/* Saved as part of the task context.  Set to pdFALSE if the task does not
require an FPU context. */
uint32_t ulTaskHasFPUContext = 0;

/*-----------------------------------------------------------*/


/*
 * See header file for description.
 */
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
StackType_t *pxOriginalTOS;

	pxOriginalTOS = pxTopOfStack;

	#if __TI_VFP_SUPPORT__
	{
		/* Ensure the stack is correctly aligned on exit. */
		pxTopOfStack--;
	}
	#endif

	/* Setup the initial stack of the task.  The stack is set exactly as
	expected by the portRESTORE_CONTEXT() macro. */

	/* First on the stack is the return address - which is the start of the as
	the task has not executed yet.  The offset is added to make the return
	address appear as it would within an IRQ ISR. */
	*pxTopOfStack = ( StackType_t ) pxCode + portINSTRUCTION_SIZE;
	pxTopOfStack--;

	*pxTopOfStack = ( StackType_t ) 0x00000000;	/* R14 */
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) pxOriginalTOS; /* Stack used when task starts goes in R13. */
	pxTopOfStack--;

	#ifdef portPRELOAD_TASK_REGISTERS
	{
		*pxTopOfStack = ( StackType_t ) 0x12121212;	/* R12 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x11111111;	/* R11 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x10101010;	/* R10 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x09090909;	/* R9 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x08080808;	/* R8 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x07070707;	/* R7 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x06060606;	/* R6 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x05050505;	/* R5 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x04040404;	/* R4 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x03030303;	/* R3 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x02020202;	/* R2 */
		pxTopOfStack--;
		*pxTopOfStack = ( StackType_t ) 0x01010101;	/* R1 */
		pxTopOfStack--;
	}
	#else
	{
		pxTopOfStack -= portSPACE_BETWEEN_TOS_AND_PARAMETERS;
	}
	#endif

	/* Function parameters are passed in R0. */
	*pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
	pxTopOfStack--;

	/* Set the status register for system mode, with interrupts enabled. */
	*pxTopOfStack = ( StackType_t ) ( ( _get_CPSR() & ~0xFF ) | portINITIAL_SPSR );

	if( ( ( uint32_t ) pxCode & 0x01UL ) != 0x00 )
	{
		/* The task will start in thumb mode. */
		*pxTopOfStack |= portTHUMB_MODE_BIT;
	}

	#ifdef __TI_VFP_SUPPORT__
	{
		pxTopOfStack--;

		/* The last thing on the stack is the tasks ulUsingFPU value, which by
		default is set to indicate that the stack frame does not include FPU
		registers. */
		*pxTopOfStack = pdFALSE;
	}
	#endif

	return pxTopOfStack;
}
/*-----------------------------------------------------------*/

static void prvSetupTimerInterrupt(void)
{
	/* Disable timer 0. */
	portRTI_GCTRL_REG &= 0xFFFFFFFEUL;

	/* Use the internal counter. */
	portRTI_TBCTRL_REG = 0x00000000U;

	/* COMPSEL0 will use the RTIFRC0 counter. */
	portRTI_COMPCTRL_REG = 0x00000000U;

	/* Initialise the counter and the prescale counter registers. */
	portRTI_CNT0_UC0_REG =  0x00000000U;
	portRTI_CNT0_FRC0_REG =  0x00000000U;

	/* Set Prescalar for RTI clock. */
	portRTI_CNT0_CPUC0_REG = 0x00000001U;
	portRTI_CNT0_COMP0_REG = ( configCPU_CLOCK_HZ / 2 ) / configTICK_RATE_HZ;
	portRTI_CNT0_UDCP0_REG = ( configCPU_CLOCK_HZ / 2 ) / configTICK_RATE_HZ;

	/* Clear interrupts. */
	portRTI_INTFLAG_REG =  0x0007000FU;
	portRTI_CLEARINTENA_REG	= 0x00070F0FU;

	/* Enable the compare 0 interrupt. */
	portRTI_SETINTENA_REG = 0x00000001U;
	portRTI_GCTRL_REG |= 0x00000001U;
}
/*-----------------------------------------------------------*/

/*
 * See header file for description.
 */
BaseType_t xPortStartScheduler(void)
{
	/* Start the timer that generates the tick ISR. */
	prvSetupTimerInterrupt();

	/* Reset the critical section nesting count read to execute the first task. */
	ulCriticalNesting = 0;

	/* Start the first task.  This is done from portASM.asm as ARM mode must be
	used. */
	vPortStartFirstTask();

	/* Should not get here! */
	return pdFAIL;
}
/*-----------------------------------------------------------*/

/*
 * See header file for description.
 */
void vPortEndScheduler(void)
{
	/* Not implemented in ports where there is nothing to return to.
	Artificially force an assert. */
	configASSERT( ulCriticalNesting == 1000UL );
}
/*-----------------------------------------------------------*/

#if configUSE_PREEMPTION == 0

	/* The cooperative scheduler requires a normal IRQ service routine to
	 * simply increment the system tick. */
	__interrupt void vPortNonPreemptiveTick( void )
	{
		/* clear clock interrupt flag */
		portRTI_INTFLAG_REG = 0x00000001;

		/* Increment the tick count - this may make a delaying task ready
		to run - but a context switch is not performed. */
		xTaskIncrementTick();
	}

 #else

	/*
	 **************************************************************************
	 * The preemptive scheduler ISR is written in assembler and can be found
	 * in the portASM.asm file. This will only get used if portUSE_PREEMPTION
	 * is set to 1 in portmacro.h
	 **************************************************************************
	 */
	void vPortPreemptiveTick( void );

#endif
/*-----------------------------------------------------------*/


/*
 * Disable interrupts, and keep a count of the nesting depth.
 */
void vPortEnterCritical( void )
{
	/* Disable interrupts as per portDISABLE_INTERRUPTS(); */
	portDISABLE_INTERRUPTS();

	/* Now interrupts are disabled ulCriticalNesting can be accessed
	directly.  Increment ulCriticalNesting to keep a count of how many times
	portENTER_CRITICAL() has been called. */
	ulCriticalNesting++;
}
/*-----------------------------------------------------------*/

/*
 * Decrement the critical nesting count, and if it has reached zero, re-enable
 * interrupts.
 */
void vPortExitCritical( void )
{
	if( ulCriticalNesting > 0 )
	{
		/* Decrement the nesting count as we are leaving a critical section. */
		ulCriticalNesting--;

		/* If the nesting level has reached zero then interrupts should be
		re-enabled. */
		if( ulCriticalNesting == 0 )
		{
			/* Enable interrupts as per portENABLE_INTERRUPTS(). */
			portENABLE_INTERRUPTS();
		}
	}
}
/*-----------------------------------------------------------*/

#if __TI_VFP_SUPPORT__

	void vPortTaskUsesFPU( void )
	{
	extern void vPortInitialiseFPSCR( void );

		/* A task is registering the fact that it needs an FPU context.  Set the
		FPU flag (saved as part of the task context. */
		ulTaskHasFPUContext = pdTRUE;

		/* Initialise the floating point status register. */
		vPortInitialiseFPSCR();
	}

#endif /* __TI_VFP_SUPPORT__ */

/*-----------------------------------------------------------*/