20120401V7.1.1-RC1/Source/portable/GCC/AVR32_UC3/port.c

@@ -0,0 +1,461 @@
+/*This file has been prepared for Doxygen automatic documentation generation.*/
+/*! \file *********************************************************************
+ *
+ * \brief FreeRTOS port source for AVR32 UC3.
+ *
+ * - Compiler:           GNU GCC for AVR32
+ * - Supported devices:  All AVR32 devices can be used.
+ * - AppNote:
+ *
+ * \author               Atmel Corporation: http://www.atmel.com \n
+ *                       Support and FAQ: http://support.atmel.no/
+ *
+ *****************************************************************************/
+
+/*
+    FreeRTOS V7.1.0 - Copyright (C) 2011 Real Time Engineers Ltd.
+	
+
+    ***************************************************************************
+     *                                                                       *
+     *    FreeRTOS tutorial books are available in pdf and paperback.        *
+     *    Complete, revised, and edited pdf reference manuals are also       *
+     *    available.                                                         *
+     *                                                                       *
+     *    Purchasing FreeRTOS documentation will not only help you, by       *
+     *    ensuring you get running as quickly as possible and with an        *
+     *    in-depth knowledge of how to use FreeRTOS, it will also help       *
+     *    the FreeRTOS project to continue with its mission of providing     *
+     *    professional grade, cross platform, de facto standard solutions    *
+     *    for microcontrollers - completely free of charge!                  *
+     *                                                                       *
+     *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
+     *                                                                       *
+     *    Thank you for using FreeRTOS, and thank you for your support!      *
+     *                                                                       *
+    ***************************************************************************
+
+
+    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.  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.
+*/
+
+
+/* Standard includes. */
+#include <sys/cpu.h>
+#include <sys/usart.h>
+#include <malloc.h>
+
+/* Scheduler includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+
+/* AVR32 UC3 includes. */
+#include <avr32/io.h>
+#include "gpio.h"
+#if( configTICK_USE_TC==1 )
+	#include "tc.h"
+#endif
+
+
+/* Constants required to setup the task context. */
+#define portINITIAL_SR            ( ( portSTACK_TYPE ) 0x00400000 ) /* AVR32 : [M2:M0]=001 I1M=0 I0M=0, GM=0 */
+#define portINSTRUCTION_SIZE      ( ( portSTACK_TYPE ) 0 )
+
+/* Each task maintains its own critical nesting variable. */
+#define portNO_CRITICAL_NESTING   ( ( unsigned long ) 0 )
+volatile unsigned long ulCriticalNesting = 9999UL;
+
+#if( configTICK_USE_TC==0 )
+	static void prvScheduleNextTick( void );
+#else
+	static void prvClearTcInt( void );
+#endif
+
+/* Setup the timer to generate the tick interrupts. */
+static void prvSetupTimerInterrupt( void );
+
+/*-----------------------------------------------------------*/
+
+/*
+ * Low-level initialization routine called during startup, before the main
+ * function.
+ * This version comes in replacement to the default one provided by Newlib.
+ * Newlib's _init_startup only calls init_exceptions, but Newlib's exception
+ * vectors are not compatible with the SCALL management in the current FreeRTOS
+ * port. More low-level initializations are besides added here.
+ */
+void _init_startup(void)
+{
+	/* Import the Exception Vector Base Address. */
+	extern void _evba;
+
+	#if configHEAP_INIT
+		extern void __heap_start__;
+		extern void __heap_end__;
+		portBASE_TYPE *pxMem;
+	#endif
+
+	/* Load the Exception Vector Base Address in the corresponding system register. */
+	Set_system_register( AVR32_EVBA, ( int ) &_evba );
+
+	/* Enable exceptions. */
+	ENABLE_ALL_EXCEPTIONS();
+
+	/* Initialize interrupt handling. */
+	INTC_init_interrupts();
+
+	#if configHEAP_INIT
+
+		/* Initialize the heap used by malloc. */
+		for( pxMem = &__heap_start__; pxMem < ( portBASE_TYPE * )&__heap_end__; )
+		{
+			*pxMem++ = 0xA5A5A5A5;
+		}
+
+	#endif
+
+	/* Give the used CPU clock frequency to Newlib, so it can work properly. */
+	set_cpu_hz( configCPU_CLOCK_HZ );
+
+	/* Code section present if and only if the debug trace is activated. */
+	#if configDBG
+	{
+		static const gpio_map_t DBG_USART_GPIO_MAP =
+		{
+			{ configDBG_USART_RX_PIN, configDBG_USART_RX_FUNCTION },
+			{ configDBG_USART_TX_PIN, configDBG_USART_TX_FUNCTION }
+		};
+
+		/* Initialize the USART used for the debug trace with the configured parameters. */
+		set_usart_base( ( void * ) configDBG_USART );
+		gpio_enable_module( DBG_USART_GPIO_MAP,
+		                    sizeof( DBG_USART_GPIO_MAP ) / sizeof( DBG_USART_GPIO_MAP[0] ) );
+		usart_init( configDBG_USART_BAUDRATE );
+	}
+	#endif
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * malloc, realloc and free are meant to be called through respectively
+ * pvPortMalloc, pvPortRealloc and vPortFree.
+ * The latter functions call the former ones from within sections where tasks
+ * are suspended, so the latter functions are task-safe. __malloc_lock and
+ * __malloc_unlock use the same mechanism to also keep the former functions
+ * task-safe as they may be called directly from Newlib's functions.
+ * However, all these functions are interrupt-unsafe and SHALL THEREFORE NOT BE
+ * CALLED FROM WITHIN AN INTERRUPT, because __malloc_lock and __malloc_unlock do
+ * not call portENTER_CRITICAL and portEXIT_CRITICAL in order not to disable
+ * interrupts during memory allocation management as this may be a very time-
+ * consuming process.
+ */
+
+/*
+ * Lock routine called by Newlib on malloc / realloc / free entry to guarantee a
+ * safe section as memory allocation management uses global data.
+ * See the aforementioned details.
+ */
+void __malloc_lock(struct _reent *ptr)
+{
+	vTaskSuspendAll();
+}
+
+/*
+ * Unlock routine called by Newlib on malloc / realloc / free exit to guarantee
+ * a safe section as memory allocation management uses global data.
+ * See the aforementioned details.
+ */
+void __malloc_unlock(struct _reent *ptr)
+{
+	xTaskResumeAll();
+}
+/*-----------------------------------------------------------*/
+
+/* Added as there is no such function in FreeRTOS. */
+void *pvPortRealloc( void *pv, size_t xWantedSize )
+{
+void *pvReturn;
+
+	vTaskSuspendAll();
+	{
+		pvReturn = realloc( pv, xWantedSize );
+	}
+	xTaskResumeAll();
+
+	return pvReturn;
+}
+/*-----------------------------------------------------------*/
+
+/* The cooperative scheduler requires a normal IRQ service routine to
+simply increment the system tick. */
+/* The preemptive scheduler is defined as "naked" as the full context is saved
+on entry as part of the context switch. */
+__attribute__((__naked__)) static void vTick( void )
+{
+	/* Save the context of the interrupted task. */
+	portSAVE_CONTEXT_OS_INT();
+
+	#if( configTICK_USE_TC==1 )
+		/* Clear the interrupt flag. */
+		prvClearTcInt();
+	#else
+		/* Schedule the COUNT&COMPARE match interrupt in (configCPU_CLOCK_HZ/configTICK_RATE_HZ)
+		clock cycles from now. */
+		prvScheduleNextTick();
+	#endif
+
+	/* Because FreeRTOS is not supposed to run with nested interrupts, put all OS
+	calls in a critical section . */
+	portENTER_CRITICAL();
+		vTaskIncrementTick();
+	portEXIT_CRITICAL();
+
+	/* Restore the context of the "elected task". */
+	portRESTORE_CONTEXT_OS_INT();
+}
+/*-----------------------------------------------------------*/
+
+__attribute__((__naked__)) void SCALLYield( void )
+{
+	/* Save the context of the interrupted task. */
+	portSAVE_CONTEXT_SCALL();
+	vTaskSwitchContext();
+	portRESTORE_CONTEXT_SCALL();
+}
+/*-----------------------------------------------------------*/
+
+/* The code generated by the GCC compiler uses the stack in different ways at
+different optimisation levels.  The interrupt flags can therefore not always
+be saved to the stack.  Instead the critical section nesting level is stored
+in a variable, which is then saved as part of the stack context. */
+__attribute__((__noinline__)) void vPortEnterCritical( void )
+{
+	/* Disable 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++;
+}
+/*-----------------------------------------------------------*/
+
+__attribute__((__noinline__)) void vPortExitCritical( void )
+{
+	if(ulCriticalNesting > portNO_CRITICAL_NESTING)
+	{
+		ulCriticalNesting--;
+		if( ulCriticalNesting == portNO_CRITICAL_NESTING )
+		{
+			/* Enable all interrupt/exception. */
+			portENABLE_INTERRUPTS();
+		}
+	}
+}
+/*-----------------------------------------------------------*/
+
+/*
+ * Initialise the stack of a task to look exactly as if a call to
+ * portSAVE_CONTEXT had been called.
+ *
+ * See header file for description.
+ */
+portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE pxCode, void *pvParameters )
+{
+	/* Setup the initial stack of the task.  The stack is set exactly as
+	expected by the portRESTORE_CONTEXT() macro. */
+
+	/* When the task starts, it will expect to find the function parameter in R12. */
+	pxTopOfStack--;
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x08080808;					/* R8 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x09090909;					/* R9 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x0A0A0A0A;					/* R10 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x0B0B0B0B;					/* R11 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) pvParameters;					/* R12 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0xDEADBEEF;					/* R14/LR */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) pxCode + portINSTRUCTION_SIZE; /* R15/PC */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) portINITIAL_SR;				/* SR */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0xFF0000FF;					/* R0 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x01010101;					/* R1 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x02020202;					/* R2 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x03030303;					/* R3 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x04040404;					/* R4 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x05050505;					/* R5 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x06060606;					/* R6 */
+	*pxTopOfStack-- = ( portSTACK_TYPE ) 0x07070707;					/* R7 */
+	*pxTopOfStack = ( portSTACK_TYPE ) portNO_CRITICAL_NESTING;			/* ulCriticalNesting */
+
+	return pxTopOfStack;
+}
+/*-----------------------------------------------------------*/
+
+portBASE_TYPE xPortStartScheduler( void )
+{
+	/* Start the timer that generates the tick ISR.  Interrupts are disabled
+	here already. */
+	prvSetupTimerInterrupt();
+
+	/* Start the first task. */
+	portRESTORE_CONTEXT();
+
+	/* Should not get here! */
+	return 0;
+}
+/*-----------------------------------------------------------*/
+
+void vPortEndScheduler( void )
+{
+	/* It is unlikely that the AVR32 port will require this function as there
+	is nothing to return to.  */
+}
+/*-----------------------------------------------------------*/
+
+/* Schedule the COUNT&COMPARE match interrupt in (configCPU_CLOCK_HZ/configTICK_RATE_HZ)
+clock cycles from now. */
+#if( configTICK_USE_TC==0 )
+	static void prvScheduleFirstTick(void)
+	{
+		unsigned long lCycles;
+
+		lCycles = Get_system_register(AVR32_COUNT);
+		lCycles += (configCPU_CLOCK_HZ/configTICK_RATE_HZ);
+		// If lCycles ends up to be 0, make it 1 so that the COMPARE and exception
+		// generation feature does not get disabled.
+		if(0 == lCycles)
+		{
+			lCycles++;
+		}
+		Set_system_register(AVR32_COMPARE, lCycles);
+	}
+	
+	__attribute__((__noinline__)) static void prvScheduleNextTick(void)
+	{
+		unsigned long lCycles, lCount;
+
+		lCycles = Get_system_register(AVR32_COMPARE);
+		lCycles += (configCPU_CLOCK_HZ/configTICK_RATE_HZ);
+		// If lCycles ends up to be 0, make it 1 so that the COMPARE and exception
+		// generation feature does not get disabled.
+		if(0 == lCycles)
+		{
+			lCycles++;
+		}
+		lCount = Get_system_register(AVR32_COUNT);
+		if( lCycles < lCount )
+		{		// We missed a tick, recover for the next.
+			lCycles += (configCPU_CLOCK_HZ/configTICK_RATE_HZ);
+		}
+		Set_system_register(AVR32_COMPARE, lCycles);
+	}
+#else
+	__attribute__((__noinline__)) static void prvClearTcInt(void)
+	{
+		AVR32_TC.channel[configTICK_TC_CHANNEL].sr;
+	}
+#endif
+/*-----------------------------------------------------------*/
+
+/* Setup the timer to generate the tick interrupts. */
+static void prvSetupTimerInterrupt(void)
+{
+#if( configTICK_USE_TC==1 )
+
+	volatile avr32_tc_t *tc = &AVR32_TC;
+
+	// Options for waveform genration.
+	tc_waveform_opt_t waveform_opt =
+	{
+	.channel  = configTICK_TC_CHANNEL,             /* Channel selection. */
+
+	.bswtrg   = TC_EVT_EFFECT_NOOP,                /* Software trigger effect on TIOB. */
+	.beevt    = TC_EVT_EFFECT_NOOP,                /* External event effect on TIOB. */
+	.bcpc     = TC_EVT_EFFECT_NOOP,                /* RC compare effect on TIOB. */
+	.bcpb     = TC_EVT_EFFECT_NOOP,                /* RB compare effect on TIOB. */
+
+	.aswtrg   = TC_EVT_EFFECT_NOOP,                /* Software trigger effect on TIOA. */
+	.aeevt    = TC_EVT_EFFECT_NOOP,                /* External event effect on TIOA. */
+	.acpc     = TC_EVT_EFFECT_NOOP,                /* RC compare effect on TIOA: toggle. */
+	.acpa     = TC_EVT_EFFECT_NOOP,                /* RA compare effect on TIOA: toggle (other possibilities are none, set and clear). */
+
+	.wavsel   = TC_WAVEFORM_SEL_UP_MODE_RC_TRIGGER,/* Waveform selection: Up mode without automatic trigger on RC compare. */
+	.enetrg   = FALSE,                             /* External event trigger enable. */
+	.eevt     = 0,                                 /* External event selection. */
+	.eevtedg  = TC_SEL_NO_EDGE,                    /* External event edge selection. */
+	.cpcdis   = FALSE,                             /* Counter disable when RC compare. */
+	.cpcstop  = FALSE,                             /* Counter clock stopped with RC compare. */
+
+	.burst    = FALSE,                             /* Burst signal selection. */
+	.clki     = FALSE,                             /* Clock inversion. */
+	.tcclks   = TC_CLOCK_SOURCE_TC2                /* Internal source clock 2. */
+	};
+
+	tc_interrupt_t tc_interrupt =
+	{
+		.etrgs=0,
+		.ldrbs=0,
+		.ldras=0,
+		.cpcs =1,
+		.cpbs =0,
+		.cpas =0,
+		.lovrs=0,
+		.covfs=0,
+	};
+
+#endif
+
+	/* Disable all interrupt/exception. */
+	portDISABLE_INTERRUPTS();
+
+	/* Register the compare interrupt handler to the interrupt controller and
+	enable the compare interrupt. */
+
+	#if( configTICK_USE_TC==1 )
+	{
+		INTC_register_interrupt(&vTick, configTICK_TC_IRQ, INT0);
+
+		/* Initialize the timer/counter. */
+		tc_init_waveform(tc, &waveform_opt);
+
+		/* Set the compare triggers.
+		Remember TC counter is 16-bits, so counting second is not possible!
+		That's why we configure it to count ms. */
+		tc_write_rc( tc, configTICK_TC_CHANNEL, ( configPBA_CLOCK_HZ / 4) / configTICK_RATE_HZ );
+
+		tc_configure_interrupts( tc, configTICK_TC_CHANNEL, &tc_interrupt );
+
+		/* Start the timer/counter. */
+		tc_start(tc, configTICK_TC_CHANNEL);
+	}
+	#else
+	{
+		INTC_register_interrupt(&vTick, AVR32_CORE_COMPARE_IRQ, INT0);
+		prvScheduleFirstTick();
+	}
+	#endif
+}