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port.c
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port.c
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/* This file has been prepared for Doxygen automatic documentation generation.*/
/*
* Copyright (C) 2012 Yuriy Kulikov
* Universitaet Erlangen-Nuernberg
* LS Informationstechnik (Kommunikationselektronik)
* Support email: Yuriy.Kulikov.87@googlemail.com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* Compiler definitions include file. */
#include "avr_compiler.h"
#include "FreeRTOSConfig.h"
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "TC_driver.h"
#include "pmic_driver.h"
/* define this as 1 if target device more than 128K of program memory.
* define as 0 if 128K or less. Devices with more memory have 24-bit program
* counter, while devices with 128K or less have only 16-bit program counter.
*/
#if defined (__AVR_ATxmega16A4__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega16D4__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega32A4__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega32D4__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega64A1__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega64A3__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega64D3__)
#define PROGRAMCOUNTER_24BIT 0
#elif defined (__AVR_ATxmega128A1__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega128A3__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega128D3__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega192A3__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega192D3__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega256A3__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega256A3B__)
#define PROGRAMCOUNTER_24BIT 1
#elif defined (__AVR_ATxmega256D3__)
#else
#error "device name should be defined in the project settings"
#endif
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the AVR XMEGA port.
*----------------------------------------------------------*/
/* Start tasks with interrupts enables. */
#define portFLAGS_INT_ENABLED ( ( portSTACK_TYPE ) 0x80 )
/*-----------------------------------------------------------*/
/* We require the address of the pxCurrentTCB variable, but don't want to know
any details of its type. */
typedef void tskTCB;
extern volatile tskTCB * volatile pxCurrentTCB;
/*-----------------------------------------------------------*/
/*
* Macro to save all the general purpose registers, the save the stack pointer
* into the TCB.
*
* The first thing we do is save the flags then disable interrupts. This is to
* guard our stack against having a context switch interrupt after we have already
* pushed the registers onto the stack - causing the 32 registers to be on the
* stack twice.
*
* r1 is set to zero as the compiler expects it to be thus, however some
* of the math routines make use of R1.
*
* The interrupts will have been disabled during the call to portSAVE_CONTEXT()
* so we need not worry about reading/writing to the stack pointer.
*/
#define portSAVE_CONTEXT() \
asm volatile ( "push r0 \n\t" \
"in r0, __SREG__ \n\t" \
"cli \n\t" \
"push r0 \n\t" \
"push r1 \n\t" \
"clr r1 \n\t" \
"push r2 \n\t" \
"push r3 \n\t" \
"push r4 \n\t" \
"push r5 \n\t" \
"push r6 \n\t" \
"push r7 \n\t" \
"push r8 \n\t" \
"push r9 \n\t" \
"push r10 \n\t" \
"push r11 \n\t" \
"push r12 \n\t" \
"push r13 \n\t" \
"push r14 \n\t" \
"push r15 \n\t" \
"push r16 \n\t" \
"push r17 \n\t" \
"push r18 \n\t" \
"push r19 \n\t" \
"push r20 \n\t" \
"push r21 \n\t" \
"push r22 \n\t" \
"push r23 \n\t" \
"push r24 \n\t" \
"push r25 \n\t" \
"push r26 \n\t" \
"push r27 \n\t" \
"push r28 \n\t" \
"push r29 \n\t" \
"push r30 \n\t" \
"push r31 \n\t" \
";in r16, 0x38 \n\t" \
";push r16 \n\t" \
";in r16, 0x39 \n\t" \
";push r16 \n\t" \
";in r16, 0x3a \n\t" \
";push r16 \n\t" \
";in r16, 0x3b \n\t" \
";push r16 \n\t" \
";in r16, 0x3c \n\t" \
";push r16 \n\t" \
"lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"in r0, 0x3d \n\t" \
"st x+, r0 \n\t" \
"in r0, 0x3e \n\t" \
"st x+, r0 \n\t" \
);
/*
* Opposite to portSAVE_CONTEXT(). Interrupts will have been disabled during
* the context save so we can write to the stack pointer.
*/
#define portRESTORE_CONTEXT() \
asm volatile ( "lds r26, pxCurrentTCB \n\t" \
"lds r27, pxCurrentTCB + 1 \n\t" \
"ld r28, x+ \n\t" \
"out __SP_L__, r28 \n\t" \
"ld r29, x+ \n\t" \
"out __SP_H__, r29 \n\t" \
";pop r16 \n\t" \
";out 0x3c, r16 \n\t" \
";pop r16 \n\t" \
";out 0x3b, r16 \n\t" \
";pop r16 \n\t" \
";out 0x3a, r16 \n\t" \
";pop r16 \n\t" \
";out 0x39, r16 \n\t" \
";pop r16 \n\t" \
";out 0x38, r16 \n\t" \
"pop r31 \n\t" \
"pop r30 \n\t" \
"pop r29 \n\t" \
"pop r28 \n\t" \
"pop r27 \n\t" \
"pop r26 \n\t" \
"pop r25 \n\t" \
"pop r24 \n\t" \
"pop r23 \n\t" \
"pop r22 \n\t" \
"pop r21 \n\t" \
"pop r20 \n\t" \
"pop r19 \n\t" \
"pop r18 \n\t" \
"pop r17 \n\t" \
"pop r16 \n\t" \
"pop r15 \n\t" \
"pop r14 \n\t" \
"pop r13 \n\t" \
"pop r12 \n\t" \
"pop r11 \n\t" \
"pop r10 \n\t" \
"pop r9 \n\t" \
"pop r8 \n\t" \
"pop r7 \n\t" \
"pop r6 \n\t" \
"pop r5 \n\t" \
"pop r4 \n\t" \
"pop r3 \n\t" \
"pop r2 \n\t" \
"pop r1 \n\t" \
"pop r0 \n\t" \
"out __SREG__, r0 \n\t" \
"pop r0 \n\t" \
);
/*-----------------------------------------------------------*/
/*
* Perform hardware setup to enable ticks from timer 1, compare match A.
*/
static void prvSetupTimerInterrupt(void);
/*-----------------------------------------------------------*/
/*
* See header file for description.
*/portSTACK_TYPE *pxPortInitialiseStack(portSTACK_TYPE *pxTopOfStack,
pdTASK_CODE pxCode, void *pvParameters) {
/*The addresses are 16 or 24 bit depending on the xmega memory, so use 32 bit variable but put only a
* part to stack.*/
uint32_t usAddress;
/* Place a few bytes of known values on the bottom of the stack.
This is just useful for debugging. */
*pxTopOfStack = 0x11;
pxTopOfStack--;
*pxTopOfStack = 0x22;
pxTopOfStack--;
*pxTopOfStack = 0x33;
pxTopOfStack--;
/* Simulate how the stack would look after a call to vPortYield() generated by
the compiler. */
/*lint -e950 -e611 -e923 Lint doesn't like this much - but nothing I can do about it. */
/* The start of the task code will be popped off the stack last, so place
it on first. */
/* Original code
* For 16-bit program counter (128K program memory or less)
usAddress = ( unsigned short ) pxCode;
*pxTopOfStack = ( portSTACK_TYPE ) ( usAddress & ( unsigned short ) 0x00ff );
pxTopOfStack--;
usAddress >>= 8;
*pxTopOfStack = ( portSTACK_TYPE ) ( usAddress & ( unsigned short ) 0x00ff );
pxTopOfStack--;*/
/* end of original code block */
/* The way it should be done for xmega with probably more than 128K program memory.
* Warning is OK here - type incompatibility does not matter - usAddress is only
* used as temporary storage */
usAddress = (uint32_t) pxCode;
*pxTopOfStack = (portSTACK_TYPE ) (usAddress & (uint32_t) 0x000000ff);
pxTopOfStack--;
usAddress >>= 8;
/* The only difference between ports for different xmegas is size of
* program counter. 16-bit for devices with 128K of program memory or less.
* 24-bit for other xmegas. */
#if PROGRAMCOUNTER_24BIT == 1
*pxTopOfStack = (portSTACK_TYPE ) (usAddress & (uint32_t) 0x000000ff);
pxTopOfStack--;
usAddress >>= 8;
#endif
*pxTopOfStack = (portSTACK_TYPE ) (usAddress & (uint32_t) 0x000000ff);
pxTopOfStack--;
/* Next simulate the stack as if after a call to portSAVE_CONTEXT().
portSAVE_CONTEXT places the flags on the stack immediately after r0
to ensure the interrupts get disabled as soon as possible, and so ensuring
the stack use is minimal should a context switch interrupt occur. */
*pxTopOfStack = (portSTACK_TYPE ) 0x00; /* R0 */
pxTopOfStack--;
*pxTopOfStack = portFLAGS_INT_ENABLED;
pxTopOfStack--;
/* Now the remaining registers. The compiler expects R1 to be 0. */
*pxTopOfStack = (portSTACK_TYPE ) 0x00; /* R1 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x02; /* R2 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x03; /* R3 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x04; /* R4 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x05; /* R5 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x06; /* R6 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x07; /* R7 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x08; /* R8 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x09; /* R9 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x10; /* R10 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x11; /* R11 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x12; /* R12 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x13; /* R13 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x14; /* R14 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x15; /* R15 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x16; /* R16 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x17; /* R17 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x18; /* R18 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x19; /* R19 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x20; /* R20 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x21; /* R21 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x22; /* R22 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x23; /* R23 */
pxTopOfStack--;
/* Place the parameter on the stack in the expected location. */
usAddress = (unsigned short) pvParameters;
*pxTopOfStack = (portSTACK_TYPE ) (usAddress & (unsigned short) 0x00ff);
pxTopOfStack--;
usAddress >>= 8;
*pxTopOfStack = (portSTACK_TYPE ) (usAddress & (unsigned short) 0x00ff);
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x26; /* R26 X */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x27; /* R27 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x28; /* R28 Y */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x29; /* R29 */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x30; /* R30 Z */
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE ) 0x31; /* R31 */
pxTopOfStack--;
/* these registers are also part of execution context
* Corresponing registars are saved and restored in saveCONTEXT and restoreCONTEXT
* TODO See datasheet for explanation
*/
//*pxTopOfStack = ( portSTACK_TYPE ) 0x38; /* 38 RAMPD */
//pxTopOfStack--;
//*pxTopOfStack = ( portSTACK_TYPE ) 0x39; /* 39 RAMPX */
//pxTopOfStack--;
//*pxTopOfStack = ( portSTACK_TYPE ) 0x3a; /* 3a RAMPY */
//pxTopOfStack--;
//*pxTopOfStack = ( portSTACK_TYPE ) 0x3b; /* 3b RAMPZ */
//pxTopOfStack--;
//*pxTopOfStack = ( portSTACK_TYPE ) 0x3c; /* 3c EIND */
//pxTopOfStack--;
/*lint +e950 +e611 +e923 */
return pxTopOfStack;
}
/*-----------------------------------------------------------*/portBASE_TYPE xPortStartScheduler(
void) {
/* Setup the hardware to generate the tick. */
prvSetupTimerInterrupt();
/* Restore the context of the first task that is going to run. */portRESTORE_CONTEXT();
/* Simulate a function call end as generated by the compiler. We will now
jump to the start of the task the context of which we have just restored. */
asm volatile ( "ret" );
/* Should not get here. */
return pdTRUE;
}
/*-----------------------------------------------------------*/
void vPortEndScheduler(void) {
/* It is unlikely that the AVR port will get stopped. If required simply
disable the tick interrupt here. */
}
/*-----------------------------------------------------------*/
/*
* Manual context switch. The first thing we do is save the registers so we
* can use a naked attribute.
*/
void vPortYield(void) __attribute__ ( ( naked ) );
void vPortYield(void) {
portSAVE_CONTEXT();
vTaskSwitchContext();
portRESTORE_CONTEXT();
asm volatile ( "ret" );
}
/*-----------------------------------------------------------*/
/*
* Context switch function used by the tick. This must be identical to
* vPortYield() from the call to vTaskSwitchContext() onwards. The only
* difference from vPortYield() is the tick count is incremented as the
* call comes from the tick ISR.
*/
void vPortYieldFromTick(void) __attribute__ ( ( naked, always_inline ) );
void vPortYieldFromTick(void) {
portSAVE_CONTEXT();
vTaskIncrementTick();
vTaskSwitchContext();
portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/
/*
* Setup timer 1 compare match A to generate a tick interrupt.
*/
static void prvSetupTimerInterrupt(void) {
//Use TCC0 as a tick counter. If this is to be changed, change ISR as well
TC0_t * tickTimer = &TCC0;
//select the clock source and pre-scale by 64
TC0_ConfigClockSource(tickTimer, TC_CLKSEL_DIV64_gc);
//set period of counter
tickTimer->PER = configCPU_CLOCK_HZ / configTICK_RATE_HZ / 64 - 1;
//enable interrupt and set low level
TC0_SetOverflowIntLevel(tickTimer, TC_OVFINTLVL_LO_gc);
//enable low level interrupts
PMIC_EnableLowLevel();
}
/*-----------------------------------------------------------*/
#if configUSE_PREEMPTION == 1
/*
* Tick ISR for preemptive scheduler. We can use a naked attribute as
* the context is saved at the start of vPortYieldFromTick(). The tick
* count is incremented after the context is saved.
*/
ISR (TCC0_OVF_vect, ISR_NAKED) {
vPortYieldFromTick();
asm volatile ( "reti" );
}
#else
/*
* Tick ISR for the cooperative scheduler. All this does is increment the
* tick count. We don't need to switch context, this can only be done by
* manual calls to taskYIELD();
*/
ISR (TCC0_OVF_vect, ISR_NAKED)
{
vTaskIncrementTick();
}
#endif