| /* | |
| FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd. | |
| *************************************************************************** | |
| * * | |
| * If you are: * | |
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| * + New to FreeRTOS, * | |
| * + Wanting to learn FreeRTOS or multitasking in general quickly * | |
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| * then take a look at the FreeRTOS eBook * | |
| * * | |
| * "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
| * http://www.FreeRTOS.org/Documentation * | |
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| * A pdf reference manual is also available. Both are usually delivered * | |
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| *************************************************************************** | |
| 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 exception 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. See the GNU General Public License for | |
| more details. You should have received a copy of the GNU General Public | |
| License and the FreeRTOS license exception along with FreeRTOS; if not it | |
| can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
| by writing to Richard Barry, contact details for whom are available on the | |
| FreeRTOS WEB site. | |
| 1 tab == 4 spaces! | |
| http://www.FreeRTOS.org - Documentation, latest information, license and | |
| contact details. | |
| http://www.SafeRTOS.com - A version that is certified for use in safety | |
| critical systems. | |
| http://www.OpenRTOS.com - Commercial support, development, porting, | |
| licensing and training services. | |
| */ | |
| /*----------------------------------------------------------- | |
| * Implementation of functions defined in portable.h for the NIOS2 port. | |
| *----------------------------------------------------------*/ | |
| /* Standard Includes. */ | |
| #include <string.h> | |
| #include <errno.h> | |
| /* Altera includes. */ | |
| #include "sys/alt_irq.h" | |
| #include "altera_avalon_timer_regs.h" | |
| #include "priv/alt_irq_table.h" | |
| /* Scheduler includes. */ | |
| #include "FreeRTOS.h" | |
| #include "task.h" | |
| /* Interrupts are enabled. */ | |
| #define portINITIAL_ESTATUS ( portSTACK_TYPE ) 0x01 | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * Setup the timer to generate the tick interrupts. | |
| */ | |
| static void prvSetupTimerInterrupt( void ); | |
| /* | |
| * Call back for the alarm function. | |
| */ | |
| void vPortSysTickHandler( void * context, alt_u32 id ); | |
| /*-----------------------------------------------------------*/ | |
| void prvReadGp( unsigned long *ulValue ) | |
| { | |
| asm( "stw gp, (r4) " ); | |
| }; | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * See header file for description. | |
| */ | |
| portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters ) | |
| { | |
| portSTACK_TYPE *pxFramePointer = pxTopOfStack - 1; | |
| portSTACK_TYPE xGlobalPointer; | |
| prvReadGp( &xGlobalPointer ); | |
| /* End of stack marker. */ | |
| *pxTopOfStack = 0xdeadbeef; | |
| pxTopOfStack--; | |
| *pxTopOfStack = ( portSTACK_TYPE ) pxFramePointer; | |
| pxTopOfStack--; | |
| *pxTopOfStack = xGlobalPointer; | |
| /* Space for R23 to R16. */ | |
| pxTopOfStack -= 9; | |
| *pxTopOfStack = ( portSTACK_TYPE ) pxCode; | |
| pxTopOfStack--; | |
| *pxTopOfStack = portINITIAL_ESTATUS; | |
| /* Space for R15 to R5. */ | |
| pxTopOfStack -= 12; | |
| *pxTopOfStack = ( portSTACK_TYPE ) pvParameters; | |
| /* Space for R3 to R1, muldiv and RA. */ | |
| pxTopOfStack -= 5; | |
| return pxTopOfStack; | |
| } | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * See header file for description. | |
| */ | |
| portBASE_TYPE xPortStartScheduler( void ) | |
| { | |
| /* Start the timer that generates the tick ISR. Interrupts are disabled | |
| here already. */ | |
| prvSetupTimerInterrupt(); | |
| /* Start the first task. */ | |
| asm volatile ( " movia r2, restore_sp_from_pxCurrentTCB \n" | |
| " jmp r2 " ); | |
| /* Should not get here! */ | |
| return 0; | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vPortEndScheduler( void ) | |
| { | |
| /* It is unlikely that the NIOS2 port will require this function as there | |
| is nothing to return to. */ | |
| } | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * Setup the systick timer to generate the tick interrupts at the required | |
| * frequency. | |
| */ | |
| void prvSetupTimerInterrupt( void ) | |
| { | |
| /* Try to register the interrupt handler. */ | |
| if ( -EINVAL == alt_irq_register( SYS_CLK_IRQ, 0x0, vPortSysTickHandler ) ) | |
| { | |
| /* Failed to install the Interrupt Handler. */ | |
| asm( "break" ); | |
| } | |
| else | |
| { | |
| /* Configure SysTick to interrupt at the requested rate. */ | |
| IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_STOP_MSK ); | |
| IOWR_ALTERA_AVALON_TIMER_PERIODL( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) & 0xFFFF ); | |
| IOWR_ALTERA_AVALON_TIMER_PERIODH( SYS_CLK_BASE, ( configCPU_CLOCK_HZ / configTICK_RATE_HZ ) >> 16 ); | |
| IOWR_ALTERA_AVALON_TIMER_CONTROL( SYS_CLK_BASE, ALTERA_AVALON_TIMER_CONTROL_CONT_MSK | ALTERA_AVALON_TIMER_CONTROL_START_MSK | ALTERA_AVALON_TIMER_CONTROL_ITO_MSK ); | |
| } | |
| /* Clear any already pending interrupts generated by the Timer. */ | |
| IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vPortSysTickHandler( void * context, alt_u32 id ) | |
| { | |
| /* Increment the Kernel Tick. */ | |
| vTaskIncrementTick(); | |
| /* If using preemption, also force a context switch. */ | |
| #if configUSE_PREEMPTION == 1 | |
| vTaskSwitchContext(); | |
| #endif | |
| /* Clear the interrupt. */ | |
| IOWR_ALTERA_AVALON_TIMER_STATUS( SYS_CLK_BASE, ~ALTERA_AVALON_TIMER_STATUS_TO_MSK ); | |
| } | |
| /*-----------------------------------------------------------*/ | |
| /** This function is a re-implementation of the Altera provided function. | |
| * The function is re-implemented to prevent it from enabling an interrupt | |
| * when it is registered. Interrupts should only be enabled after the FreeRTOS.org | |
| * kernel has its scheduler started so that contexts are saved and switched | |
| * correctly. | |
| */ | |
| int alt_irq_register( alt_u32 id, void* context, void (*handler)(void*, alt_u32) ) | |
| { | |
| int rc = -EINVAL; | |
| alt_irq_context status; | |
| if (id < ALT_NIRQ) | |
| { | |
| /* | |
| * interrupts are disabled while the handler tables are updated to ensure | |
| * that an interrupt doesn't occur while the tables are in an inconsistent | |
| * state. | |
| */ | |
| status = alt_irq_disable_all (); | |
| alt_irq[id].handler = handler; | |
| alt_irq[id].context = context; | |
| rc = (handler) ? alt_irq_enable (id): alt_irq_disable (id); | |
| /* alt_irq_enable_all(status); This line is removed to prevent the interrupt from being immediately enabled. */ | |
| } | |
| return rc; | |
| } | |
| /*-----------------------------------------------------------*/ | |