/*
 * FreeRTOS Kernel V10.6.1
 * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 * Copyright (C) 2018 - 2021 Xilinx, Inc. All rights reserved.
 * Copyright (c) 2022 - 2025 Advanced Micro Devices, Inc. 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
 *
 */

/* Standard includes. */
#include <stdlib.h>

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

/* Xilinx includes. */
#include "xscugic.h"
#if defined(XPAR_XILTIMER_ENABLED) || defined(SDT)
#include "bspconfig.h"
#include "xinterrupt_wrap.h"
#endif

#if !defined(XPAR_XILTIMER_ENABLED) && defined(XPM_SUPPORT)
#include "xttcps.h"
#endif

#ifndef configINTERRUPT_CONTROLLER_BASE_ADDRESS
    #error configINTERRUPT_CONTROLLER_BASE_ADDRESS must be defined.  Refer to Cortex-A equivalent: http: /*www.FreeRTOS.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html */
#endif

#ifndef configINTERRUPT_CONTROLLER_CPU_INTERFACE_OFFSET
    #error configINTERRUPT_CONTROLLER_CPU_INTERFACE_OFFSET must be defined.  Refer to Cortex-A equivalent: http: /*www.FreeRTOS.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html */
#endif

#ifndef configUNIQUE_INTERRUPT_PRIORITIES
    #error configUNIQUE_INTERRUPT_PRIORITIES must be defined.  Refer to Cortex-A equivalent: http: /*www.FreeRTOS.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html */
#endif

#ifndef configSETUP_TICK_INTERRUPT
    #error configSETUP_TICK_INTERRUPT() must be defined.  Refer to Cortex-A equivalent: http: /*www.FreeRTOS.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html */
#endif /* configSETUP_TICK_INTERRUPT */

#ifndef configMAX_API_CALL_INTERRUPT_PRIORITY
    #error configMAX_API_CALL_INTERRUPT_PRIORITY must be defined.  Refer to Cortex-A equivalent: http: /*www.FreeRTOS.org/Using-FreeRTOS-on-Cortex-A-Embedded-Processors.html */
#endif

#if configMAX_API_CALL_INTERRUPT_PRIORITY == 0
	#error configMAX_API_CALL_INTERRUPT_PRIORITY must not be set to 0
#endif

#if configMAX_API_CALL_INTERRUPT_PRIORITY > configUNIQUE_INTERRUPT_PRIORITIES
	#error configMAX_API_CALL_INTERRUPT_PRIORITY must be less than or equal to configUNIQUE_INTERRUPT_PRIORITIES as the lower the numeric priority value the higher the logical interrupt priority
#endif

#if configUSE_PORT_OPTIMISED_TASK_SELECTION == 1
	/* Check the configuration. */
	#if( configMAX_PRIORITIES > 32 )
		#error configUSE_PORT_OPTIMISED_TASK_SELECTION can only be set to 1 when configMAX_PRIORITIES is less than or equal to 32.  It is very rare that a system requires more than 10 to 15 difference priorities as tasks that share a priority will time slice.
	#endif
#endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */

/* In case security extensions are implemented. */
#if configMAX_API_CALL_INTERRUPT_PRIORITY <= ( configUNIQUE_INTERRUPT_PRIORITIES / 2 )
	#error configMAX_API_CALL_INTERRUPT_PRIORITY must be greater than ( configUNIQUE_INTERRUPT_PRIORITIES / 2 )
#endif

/*
 * __ARM_FP is defined by the c preprocessor when FPU support is enabled,
 * usually with the -mfpu= argument and -mfloat-abi=.
 *
 * Note: Some implementations of the c standard library may use FPU registers
 *       for generic memory operations (memcpy, etc).
 *       When setting configUSE_TASK_FPU_SUPPORT == 1, care must be taken to
 *       ensure that the FPU registers are not used without an FPU context.
 */
#if ( configUSE_TASK_FPU_SUPPORT == 0 )
    #ifdef __ARM_FP
        #error __ARM_FP is defined, so configUSE_TASK_FPU_SUPPORT must be set to either to 1 or 2.
    #endif /* __ARM_FP */
#elif ( configUSE_TASK_FPU_SUPPORT == 1 ) || ( configUSE_TASK_FPU_SUPPORT == 2 )
    #ifndef __ARM_FP
        #error __ARM_FP is not defined, so configUSE_TASK_FPU_SUPPORT must be set to 0.
    #endif /* __ARM_FP */
#endif /* configUSE_TASK_FPU_SUPPORT */

/*
 * Some vendor specific files default configCLEAR_TICK_INTERRUPT() in
 * portmacro.h.
 */
#ifndef configCLEAR_TICK_INTERRUPT
	#define configCLEAR_TICK_INTERRUPT()
#endif

/* A critical section is exited when the critical section nesting count reaches
this value. */
#define portNO_CRITICAL_NESTING			( ( uint32_t ) 0 )

/* In all GICs 255 can be written to the priority mask register to unmask all
(but the lowest) interrupt priority. */
#define portUNMASK_VALUE				( 0xFFUL )

/* Tasks are not created with a floating point context, but can be given a
floating point context after they have been created.  A variable is stored as
part of the tasks context that holds portNO_FLOATING_POINT_CONTEXT if the task
does not have an FPU context, or any other value if the task does have an FPU
context. */
#define portNO_FLOATING_POINT_CONTEXT	( ( StackType_t ) 0 )

/* Constants required to setup the initial task context. */
#define portINITIAL_SPSR				( ( StackType_t ) 0x1f ) /* System mode, ARM mode, IRQ enabled FIQ enabled. */
#define portTHUMB_MODE_BIT				( ( StackType_t ) 0x20 )
#define portINTERRUPT_ENABLE_BIT		( 0x80UL )
#define portTHUMB_MODE_ADDRESS			( 0x01UL )

/* Used by portASSERT_IF_INTERRUPT_PRIORITY_INVALID() when ensuring the binary
point is zero. */
#define portBINARY_POINT_BITS			( ( uint8_t ) 0x03 )

/* Masks all bits in the APSR other than the mode bits. */
#define portAPSR_MODE_BITS_MASK			( 0x1F )

/* The value of the mode bits in the APSR when the CPU is executing in user
mode. */
#define portAPSR_USER_MODE				( 0x10 )

/* The critical section macros only mask interrupts up to an application
determined priority level.  Sometimes it is necessary to turn interrupt off in
the CPU itself before modifying certain hardware registers. */
#define portCPU_IRQ_DISABLE()										\
	__asm volatile ( "CPSID i" ::: "memory" );						\
	__asm volatile ( "DSB" );										\
	__asm volatile ( "ISB" );

#define portCPU_IRQ_ENABLE()										\
	__asm volatile ( "CPSIE i" ::: "memory" );						\
	__asm volatile ( "DSB" );										\
	__asm volatile ( "ISB" );


/* ARM Cortex-R52 has GICv3 internal to it and the CPU interface
register accesses need to be done using coprocessor instructions */
#if !defined(ARMR52)
/* Macro to unmask all interrupt priorities. */
#define portCLEAR_INTERRUPT_MASK()									\
{																	\
	portCPU_IRQ_DISABLE();											\
	Xil_Out32(portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS, portUNMASK_VALUE);			\
	__asm volatile (	"DSB		\n"								\
						"ISB		\n" );							\
	portCPU_IRQ_ENABLE();											\
}
#else
#define portCLEAR_INTERRUPT_MASK()									\
{																	\
	portCPU_IRQ_DISABLE();											\
	XScuGic_set_priority_filter(portUNMASK_VALUE); \
	__asm volatile (	"DSB		\n"								\
						"ISB		\n" );							\
	portCPU_IRQ_ENABLE();											\
}
#endif

#if !defined(ARMR52)
#define portINTERRUPT_PRIORITY_REGISTER_OFFSET		0x400UL
#else
#define portINTERRUPT_PRIORITY_REGISTER_OFFSET          0x420UL
#endif
#define portMAX_8_BIT_VALUE							( ( uint8_t ) 0xff )
#define portBIT_0_SET								( ( uint8_t ) 0x01 )

/* Let the user override the pre-loading of the initial LR with the address of
prvTaskExitError() in case is messes up unwinding of the stack in the
debugger. */
#define portTASK_RETURN_ADDRESS	configTASK_RETURN_ADDRESS

/* The space on the stack required to hold the FPU registers.
 * vfpv3-d16 has 16 64 bit registers or 32 32 bit registers. plus
 * a 32 bit status register
 */
#if defined (ARMR52)
#define portFPU_REGISTER_WORDS ( (32 * 2) + 1)
#else
#define portFPU_REGISTER_WORDS ( (16 * 2) + 1)
#endif
/*-----------------------------------------------------------*/

/*
 * Starts the first task executing.  This function is necessarily written in
 * assembly code so is implemented in portASM.s.
 */
extern void vPortRestoreTaskContext( void );

/*
 * Used to catch tasks that attempt to return from their implementing function.
 */
static void prvTaskExitError( void );

#if ( configUSE_TASK_FPU_SUPPORT != 0 )

/*
 * If the application provides an implementation of vApplicationIRQHandler(),
 * then it will get called directly without saving the FPU registers on
 * interrupt entry, and this weak implementation of
 * vApplicationFPUSafeIRQHandler() is just provided to remove linkage errors -
 * it should never actually get called so its implementation contains a
 * call to configASSERT() that will always fail.
 *
 * If the application provides its own implementation of
 * vApplicationFPUSafeIRQHandler() then the implementation of
 * vApplicationIRQHandler() provided in portASM.S will save the FPU registers
 * before calling it.
 *
 * Therefore, if the application writer wants FPU registers to be saved on
 * interrupt entry their IRQ handler must be called
 * vApplicationFPUSafeIRQHandler(), and if the application writer does not want
 * FPU registers to be saved on interrupt entry their IRQ handler must be
 * called vApplicationIRQHandler().
 */
    void vApplicationFPUSafeIRQHandler( uint32_t ulICCIAR ) __attribute__( ( weak ) );
#endif /* configUSE_TASK_FPU_SUPPORT != 0 */

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

/* A variable is used to keep track of the critical section nesting.  This
variable has to be stored as part of the task context and must be initialised to
a non zero value to ensure interrupts don't inadvertently become unmasked before
the scheduler starts.  As it is stored as part of the task context it will
automatically be set to 0 when the first task is started. */
volatile uint32_t ulCriticalNesting = 9999UL;

/*
 * The instance of the interrupt controller used by this port.  This is required
 * by the Xilinx library API functions.
 */
#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
extern XScuGic xInterruptController;
#if !defined(XPAR_XILTIMER_ENABLED) && defined(XPM_SUPPORT)
extern XTtcPs xTimerInstance;
#endif
#else
uintptr_t IntrControllerAddr = configINTERRUPT_CONTROLLER_BASE_ADDRESS;
#endif

/* Saved as part of the task context.  If ulPortTaskHasFPUContext is non-zero then
a floating point context must be saved and restored for the task. */
uint32_t ulPortTaskHasFPUContext = pdFALSE;

/* Set to 1 to pend a context switch from an ISR. */
uint32_t ulPortYieldRequired = pdFALSE;

/* Counts the interrupt nesting depth.  A context switch is only performed if
if the nesting depth is 0. */
uint32_t ulPortInterruptNesting = 0UL;
/*
 * Global counter used for calculation of run time statistics of tasks.
 * Defined only when the relevant option is turned on
 */
#if (configGENERATE_RUN_TIME_STATS==1)
volatile uint32_t ulHighFrequencyTimerTicks;
#endif

#if !defined(ARMR52)
/* Used in asm code. */
__attribute__(( used )) const uint32_t ulICCIAR = portICCIAR_INTERRUPT_ACKNOWLEDGE_REGISTER_ADDRESS;
__attribute__(( used )) const uint32_t ulICCEOIR = portICCEOIR_END_OF_INTERRUPT_REGISTER_ADDRESS;
__attribute__(( used )) const uint32_t ulICCPMR	= portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS;
#endif
__attribute__(( used )) const uint32_t ulMaxAPIPriorityMask = ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT );

/*-----------------------------------------------------------*/
/*
 * Initialise the interrupt controller instance.
 */
static int32_t prvInitialiseInterruptController( void );

/* Ensure the interrupt controller instance variable is initialised before it is
 * used, and that the initialisation only happens once.
 */
static int32_t prvEnsureInterruptControllerIsInitialised( void );

/*
 * See header file for description.
 */
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
	/* Setup the initial stack of the task.  The stack is set exactly as
	expected by the portRESTORE_CONTEXT() macro.

	The fist real value on the stack is the status register, which is set for
	system mode, with interrupts enabled.  A few NULLs are added first to ensure
	GDB does not try decoding a non-existent return address. */
	*pxTopOfStack = ( StackType_t ) NULL;
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) NULL;
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) NULL;
	pxTopOfStack--;
	*pxTopOfStack = ( StackType_t ) portINITIAL_SPSR;

	if( ( ( uint32_t ) pxCode & portTHUMB_MODE_ADDRESS ) != 0x00UL )
	{
		/* The task will start in THUMB mode. */
		*pxTopOfStack |= portTHUMB_MODE_BIT;
	}

	pxTopOfStack--;

	/* Next the return address, which in this case is the start of the task. */
	*pxTopOfStack = ( StackType_t ) pxCode;
	pxTopOfStack--;

	/* Next all the registers other than the stack pointer. */
	*pxTopOfStack = ( StackType_t ) portTASK_RETURN_ADDRESS;	/* R14 */
	pxTopOfStack--;
	*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--;
	*pxTopOfStack = ( StackType_t ) pvParameters; /* R0 */
	pxTopOfStack--;

	/* The task will start with a critical nesting count of 0 as interrupts are
	enabled. */
	*pxTopOfStack = portNO_CRITICAL_NESTING;


#if (configUSE_TASK_FPU_SUPPORT == 1)
	{
	/* The task will start without a floating point context.  A task that uses
	the floating point hardware must call vPortTaskUsesFPU() before executing
	any floating point instructions. */
		pxTopOfStack--;
	*pxTopOfStack = portNO_FLOATING_POINT_CONTEXT;
	}
#elif (configUSE_TASK_FPU_SUPPORT == 2)
	{
		/* The task will start with a floating point context.
		 * Leave enough space for FPU registers and ensure that they are zeroed out.
		 */
		pxTopOfStack -= portFPU_REGISTER_WORDS;
		memset(pxTopOfStack, 0x00, portFPU_REGISTER_WORDS * sizeof(StackType_t));

		pxTopOfStack--;
		*pxTopOfStack = pdTRUE;
		ulPortTaskHasFPUContext = pdTRUE;
	}
    #elif ( configUSE_TASK_FPU_SUPPORT != 0 )
	{
        #error Invalid configUSE_TASK_FPU_SUPPORT setting - configUSE_TASK_FPU_SUPPORT must be set to 0, 1, or 2.
	}
#endif

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

static void prvTaskExitError( void )
{
	/* A function that implements a task must not exit or attempt to return to
	its caller as there is nothing to return to.  If a task wants to exit it
	should instead call vTaskDelete( NULL ).

	Artificially force an assert() to be triggered if configASSERT() is
	defined, then stop here so application writers can catch the error. */
	xil_printf("Warning: return statement has been called from task %s, deleting it\n",pcTaskGetName(NULL));
	if (uxTaskGetNumberOfTasks() == 2)
	{
		xil_printf("Warning: Kernel does not have any task to manage other than idle task\n");
	}
	vTaskDelete( NULL );
}
/*-----------------------------------------------------------*/

#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
BaseType_t xPortInstallInterruptHandler( uint8_t ucInterruptID, XInterruptHandler pxHandler, void *pvCallBackRef )
#else
BaseType_t xPortInstallInterruptHandler( uint16_t ucInterruptID, XInterruptHandler pxHandler, void *pvCallBackRef )
#endif
{
int32_t lReturn;

	/* An API function is provided to install an interrupt handler because the
	interrupt controller instance variable is private to this file. */
	lReturn = prvEnsureInterruptControllerIsInitialised();
	if( lReturn == pdPASS )
	{
#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
		lReturn = XScuGic_Connect( &xInterruptController, ucInterruptID, pxHandler, pvCallBackRef );
#else
		lReturn = XConnectToInterruptCntrl(ucInterruptID, pxHandler, pvCallBackRef, IntrControllerAddr);
#endif
	}
	if( lReturn == XST_SUCCESS )
	{
		lReturn = pdPASS;
	}
	configASSERT( lReturn == pdPASS );

	return lReturn;
}
/*-----------------------------------------------------------*/

static int32_t prvEnsureInterruptControllerIsInitialised( void )
{
static int32_t lInterruptControllerInitialised = pdFALSE;
int32_t lReturn;

	/* Ensure the interrupt controller instance variable is initialised before
	it is used, and that the initialisation only happens once. */
	if( lInterruptControllerInitialised != pdTRUE )
	{
		lReturn = prvInitialiseInterruptController();

		if( lReturn == pdPASS )
		{
			lInterruptControllerInitialised = pdTRUE;
		}
	}
	else
	{
		lReturn = pdPASS;
	}

	return lReturn;
}
/*-----------------------------------------------------------*/

static int32_t prvInitialiseInterruptController( void )
{
#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
BaseType_t xStatus;
XScuGic_Config *pxGICConfig;

	/* Initialize the interrupt controller driver. */
	pxGICConfig = XScuGic_LookupConfig( configINTERRUPT_CONTROLLER_DEVICE_ID );
	xStatus = XScuGic_CfgInitialize( &xInterruptController, pxGICConfig, pxGICConfig->CpuBaseAddress );
	/* Connect the interrupt controller interrupt handler to the hardware
	interrupt handling logic in the ARM processor. */
	Xil_ExceptionRegisterHandler( XIL_EXCEPTION_ID_IRQ_INT,
								( Xil_ExceptionHandler ) XScuGic_InterruptHandler,
								&xInterruptController);
	/* Enable interrupts in the ARM. */
	Xil_ExceptionEnable();
#else
	int xStatus;
	xStatus = XConfigInterruptCntrl(IntrControllerAddr);
#endif
		if( xStatus == XST_SUCCESS )
		{
			xStatus = pdPASS;
#if defined(XPAR_XILTIMER_ENABLED) || defined(SDT)
			XRegisterInterruptHandler(NULL, IntrControllerAddr);
                        Xil_ExceptionInit();
                        Xil_ExceptionEnable();
#endif
		}
		else
		{
			xStatus = pdFAIL;
		}
	configASSERT( xStatus == pdPASS );

	return xStatus;
}
/*-----------------------------------------------------------*/

void vPortEnableInterrupt( uint8_t ucInterruptID )
{
int32_t lReturn;

	/* An API function is provided to enable an interrupt in the interrupt
	controller. */
	lReturn = prvEnsureInterruptControllerIsInitialised();
	if( lReturn == pdPASS )
	{
#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
		XScuGic_Enable( &xInterruptController, ucInterruptID );
#else
		XEnableIntrId(ucInterruptID, IntrControllerAddr);
#endif
	}
	configASSERT( lReturn );
}
/*-----------------------------------------------------------*/

void vPortDisableInterrupt( uint8_t ucInterruptID )
{
int32_t lReturn;

	/* An API function is provided to disable an interrupt in the interrupt
	controller. */
	lReturn = prvEnsureInterruptControllerIsInitialised();
	if( lReturn == pdPASS )
	{
#if !defined(XPAR_XILTIMER_ENABLED) && !defined(SDT)
		XScuGic_Disable( &xInterruptController, ucInterruptID );
#else
		XDisableIntrId(ucInterruptID, IntrControllerAddr);
#endif
	}
	configASSERT( lReturn );
}
/*-----------------------------------------------------------*/

BaseType_t xPortStartScheduler( void )
{
uint32_t ulAPSR, ulCycles = 8; /* 8 bits per byte. */
#if defined(ARMR52)
uint32_t ulBpr;
#endif

	#if( configASSERT_DEFINED == 1 )
	{
		volatile uint32_t ucOriginalPriority;
#if !defined(ARMR52)
		volatile uint32_t ucFirstUserPriorityRegister = ( configINTERRUPT_CONTROLLER_BASE_ADDRESS + portINTERRUPT_PRIORITY_REGISTER_OFFSET );
#else
		volatile uint32_t ucFirstUserPriorityRegister = ( configINTERRUPT_CONTROLLER_BASE_ADDRESS + portINTERRUPT_PRIORITY_REGISTER_OFFSET);
#endif
		volatile uint8_t ucMaxPriorityValue;

		/* Determine how many priority bits are implemented in the GIC.

		Save the interrupt priority value that is about to be clobbered. */
		ucOriginalPriority = Xil_In32(ucFirstUserPriorityRegister);

		/* Determine the number of priority bits available.  First write to
		all possible bits. */
		Xil_Out32(ucFirstUserPriorityRegister, portMAX_8_BIT_VALUE);

		/* Read the value back to see how many bits stuck. */
		ucMaxPriorityValue = Xil_In32(ucFirstUserPriorityRegister);

		/* Shift to the least significant bits. */
		while( ( ucMaxPriorityValue & portBIT_0_SET ) != portBIT_0_SET )
		{
			ucMaxPriorityValue >>= ( uint8_t ) 0x01;

			/* If ulCycles reaches 0 then ucMaxPriorityValue must have been
			read as 0, indicating a misconfiguration. */
			ulCycles--;
			if( ulCycles == 0 )
			{
				break;
			}
		}

		Xil_Out32(ucFirstUserPriorityRegister, ucOriginalPriority);
	}
	#endif /* conifgASSERT_DEFINED */

	/* Only continue if the CPU is not in User mode.  The CPU must be in a
	Privileged mode for the scheduler to start. */
	__asm volatile ( "MRS %0, APSR" : "=r" ( ulAPSR ) :: "memory" );
	ulAPSR &= portAPSR_MODE_BITS_MASK;
	configASSERT( ulAPSR != portAPSR_USER_MODE );

	if( ulAPSR != portAPSR_USER_MODE )
	{
		/* Only continue if the binary point value is set to its lowest possible
		setting.  See the comments in vPortValidateInterruptPriority() below for
		more information. */
#if !defined(ARMR52)
		configASSERT( ( Xil_In32(portICCBPR_BINARY_POINT_REGISTER_ADDRESS) & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
		if( ( Xil_In32(portICCBPR_BINARY_POINT_REGISTER_ADDRESS) & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE)
#else
		ulBpr = mfcp(XREG_ICC_BPR1_EL1);
		configASSERT( ( ulBpr & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
		if( ( ulBpr & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE )
#endif
		{
			/* Interrupts are turned off in the CPU itself to ensure tick does
			not execute	while the scheduler is being started.  Interrupts are
			automatically turned back on in the CPU when the first task starts
			executing. */
			portCPU_IRQ_DISABLE();

			/* Start the timer that generates the tick ISR. */
			configSETUP_TICK_INTERRUPT();

			/* Start the first task executing. */
			vPortRestoreTaskContext();
		}
	}

	/* Will only get here if vTaskStartScheduler() was called with the CPU in
	a non-privileged mode or the binary point register was not set to its lowest
	possible value.  prvTaskExitError() is referenced to prevent a compiler
	warning about it being defined but not referenced in the case that the user
	defines their own exit address. */
	( void ) prvTaskExitError;
	return 0;
}
/*-----------------------------------------------------------*/

void vPortEndScheduler( void )
{
	/* Not implemented in ports where there is nothing to return to. */
	/* Release ticktimer, so timer is left in its original condition */
#if defined (XPM_SUPPORT)
#if !defined (XPAR_XILTIMER_ENABLED)
	XTtcPs_Release(&xTimerInstance);
#else
	XTimer_ReleaseTickTimer();
#endif
#endif
	/* Artificially force an assert. */
	configASSERT( ulCriticalNesting == 1000UL );

	/*TODO: vPortEndScheduler should release all the resources allocated
	 * by the kernel.*/
}
/*-----------------------------------------------------------*/

void vPortEnterCritical( void )
{
	/* Mask interrupts up to the max syscall interrupt priority. */
	ulPortSetInterruptMask();

	/* 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++;

	/* This is not the interrupt safe version of the enter critical function so
	assert() if it is being called from an interrupt context.  Only API
	functions that end in "FromISR" can be used in an interrupt.  Only assert if
	the critical nesting count is 1 to protect against recursive calls if the
	assert function also uses a critical section. */
	if( ulCriticalNesting == 1 )
	{
		configASSERT( ulPortInterruptNesting == 0 );
	}
}
/*-----------------------------------------------------------*/

void vPortExitCritical( void )
{
	if( ulCriticalNesting > portNO_CRITICAL_NESTING )
	{
		/* Decrement the nesting count as the critical section is being
		exited. */
		ulCriticalNesting--;

		/* If the nesting level has reached zero then all interrupt
		priorities must be re-enabled. */
		if( ulCriticalNesting == portNO_CRITICAL_NESTING )
		{
			/* Critical nesting has reached zero so all interrupt priorities
			should be unmasked. */
			portCLEAR_INTERRUPT_MASK();
		}
	}
}
/*-----------------------------------------------------------*/

void FreeRTOS_Tick_Handler( void )
{
	/*
	 * The Xilinx implementation of generating run time task stats uses the same timer used for generating
	 * FreeRTOS ticks. In case user decides to generate run time stats the tick handler is called more
	 * frequently (10 times faster). The timer/tick handler uses logic to handle the same. It handles
	 * the FreeRTOS tick once per 10 interrupts.
	 * For handling generation of run time stats, it increments a pre-defined counter every time the
	 * interrupt handler executes.
	 */
#if (configGENERATE_RUN_TIME_STATS == 1)
	ulHighFrequencyTimerTicks++;
	if (!(ulHighFrequencyTimerTicks % 10))
#endif
	{
	/* Set interrupt mask before altering scheduler structures.   The tick
	handler runs at the lowest priority, so interrupts cannot already be masked,
	so there is no need to save and restore the current mask value.  It is
	necessary to turn off interrupts in the CPU itself while the ICCPMR is being
	updated. */
	portCPU_IRQ_DISABLE();
#if !defined(ARMR52)
	Xil_Out32(portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS, ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ));
#else
	mtcp(XREG_ICC_PMR_EL1, ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ));
#endif
	__asm volatile (	"dsb		\n"
						"isb		\n" ::: "memory" );
	portCPU_IRQ_ENABLE();

	/* Increment the RTOS tick. */
	if( xTaskIncrementTick() != pdFALSE )
	{
		ulPortYieldRequired = pdTRUE;
	}
	}

	/* Ensure all interrupt priorities are active again. */
	portCLEAR_INTERRUPT_MASK();
	configCLEAR_TICK_INTERRUPT();
}
/*-----------------------------------------------------------*/
#if ( configUSE_TASK_FPU_SUPPORT == 1 )
void vPortTaskUsesFPU( void )
{
uint32_t ulInitialFPSCR = 0;

	/* A task is registering the fact that it needs an FPU context.  Set the
	FPU flag (which is saved as part of the task context). */
	ulPortTaskHasFPUContext = pdTRUE;

	/* Initialise the floating point status register. */
	__asm volatile ( "FMXR 	FPSCR, %0" :: "r" (ulInitialFPSCR) : "memory" );
}
#endif
/*-----------------------------------------------------------*/

void vPortClearInterruptMask( uint32_t ulNewMaskValue )
{
	if( ulNewMaskValue == pdFALSE )
	{
		portCLEAR_INTERRUPT_MASK();
	}
}
/*-----------------------------------------------------------*/

uint32_t ulPortSetInterruptMask( void )
{
uint32_t ulReturn;
#if defined(ARMR52)
uint32_t ulPmr;
#endif

	/* Interrupt in the CPU must be turned off while the ICCPMR is being
	updated. */
	portCPU_IRQ_DISABLE();
#if !defined(ARMR52)
	if( Xil_In32(portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS) == ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) )
#else
	ulPmr = mfcp(XREG_ICC_PMR_EL1);
	if (ulPmr ==  ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT))
#endif
	{
		/* Interrupts were already masked. */
		ulReturn = pdTRUE;
	}
	else
	{
		ulReturn = pdFALSE;
#if !defined(ARMR52)
		Xil_Out32(portICCPMR_PRIORITY_MASK_REGISTER_ADDRESS, ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ));
#else
		mtcp(XREG_ICC_PMR_EL1, ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ));
#endif
		__asm volatile (	"dsb		\n"
							"isb		\n" ::: "memory" );
	}
	portCPU_IRQ_ENABLE();

	return ulReturn;
}
/*-----------------------------------------------------------*/

#if( configASSERT_DEFINED == 1 )

	void vPortValidateInterruptPriority( void )
	{
#if defined(ARMR52)
		unsigned int ulRpr;
		unsigned int ulBpr;
#endif
		/* The following assertion will fail if a service routine (ISR) for
		an interrupt that has been assigned a priority above
		configMAX_SYSCALL_INTERRUPT_PRIORITY calls an ISR safe FreeRTOS API
		function.  ISR safe FreeRTOS API functions must *only* be called
		from interrupts that have been assigned a priority at or below
		configMAX_SYSCALL_INTERRUPT_PRIORITY.

		Numerically low interrupt priority numbers represent logically high
		interrupt priorities, therefore the priority of the interrupt must
		be set to a value equal to or numerically *higher* than
		configMAX_SYSCALL_INTERRUPT_PRIORITY.

		FreeRTOS maintains separate thread and ISR API functions to ensure
		interrupt entry is as fast and simple as possible. */

#if !defined(ARMR52)
		configASSERT( Xil_In32(portICCRPR_RUNNING_PRIORITY_REGISTER_ADDRESS) >= ( uint32_t ) ( configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) );
#else
		ulRpr = mfcp(XREG_ICC_RPR_EL1);
		configASSERT( ulRpr >= ( uint32_t ) (configMAX_API_CALL_INTERRUPT_PRIORITY << portPRIORITY_SHIFT ) );
#endif

		/* Priority grouping:  The interrupt controller (GIC) allows the bits
		that define each interrupt's priority to be split between bits that
		define the interrupt's pre-emption priority bits and bits that define
		the interrupt's sub-priority.  For simplicity all bits must be defined
		to be pre-emption priority bits.  The following assertion will fail if
		this is not the case (if some bits represent a sub-priority).

		The priority grouping is configured by the GIC's binary point register
		(ICCBPR).  Writing 0 to ICCBPR will ensure it is set to its lowest
		possible value (which may be above 0). */
#if !defined(ARMR52)
		configASSERT( ( Xil_In32(portICCBPR_BINARY_POINT_REGISTER_ADDRESS) & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
#else
		ulBpr = mfcp(XREG_ICC_BPR1_EL1);
		configASSERT( ( ulBpr & portBINARY_POINT_BITS ) <= portMAX_BINARY_POINT_VALUE );
#endif
	}

#endif /* configASSERT_DEFINED */

#if( configGENERATE_RUN_TIME_STATS == 1 )
/*
 * For Xilinx implementation this is a dummy function that does a redundant operation
 * of zeroing out the global counter.
 * It is called by FreeRTOS kernel.
 */
void xCONFIGURE_TIMER_FOR_RUN_TIME_STATS (void)
{
	ulHighFrequencyTimerTicks = 0;
}
/*
 * For Xilinx implementation this function returns the global counter used for
 * run time task stats calculation.
 * It is called by FreeRTOS kernel task handling logic.
 */
uint32_t xGET_RUN_TIME_COUNTER_VALUE (void)
{
	return ulHighFrequencyTimerTicks;
}
#endif
/*-----------------------------------------------------------*/
