| /* |
| * FreeRTOS Kernel V10.4.2 |
| * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| * |
| * 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 |
| * |
| * 1 tab == 4 spaces! |
| */ |
| |
| |
| #include <stdlib.h> |
| |
| #include <avr/io.h> |
| #include <avr/interrupt.h> |
| #include <avr/wdt.h> |
| |
| #include "FreeRTOS.h" |
| #include "task.h" |
| |
| /*----------------------------------------------------------- |
| * Implementation of functions defined in portable.h for the AVR port. |
| *----------------------------------------------------------*/ |
| |
| /* Start tasks with interrupts enabled. */ |
| #define portFLAGS_INT_ENABLED ( (StackType_t) 0x80 ) |
| |
| #if defined( portUSE_WDTO) |
| #warning "Watchdog Timer used for scheduler." |
| #define portSCHEDULER_ISR WDT_vect |
| |
| #elif defined( portUSE_TIMER0 ) |
| /* Hardware constants for Timer0. */ |
| #warning "Timer0 used for scheduler." |
| #define portSCHEDULER_ISR TIMER0_COMPA_vect |
| #define portCLEAR_COUNTER_ON_MATCH ( (uint8_t) _BV(WGM01) ) |
| #define portPRESCALE_1024 ( (uint8_t) (_BV(CS02)|_BV(CS00)) ) |
| #define portCLOCK_PRESCALER ( (uint32_t) 1024 ) |
| #define portCOMPARE_MATCH_A_INTERRUPT_ENABLE ( (uint8_t) _BV(OCIE0A) ) |
| #define portOCRL OCR0A |
| #define portTCCRa TCCR0A |
| #define portTCCRb TCCR0B |
| #define portTIMSK TIMSK0 |
| #define portTIFR TIFR0 |
| |
| #endif |
| |
| /*-----------------------------------------------------------*/ |
| |
| /* We require the address of the pxCurrentTCB variable, but don't want to know |
| any details of its type. */ |
| typedef void TCB_t; |
| extern volatile TCB_t * volatile pxCurrentTCB; |
| |
| /*-----------------------------------------------------------*/ |
| |
| /** |
| Enable the watchdog timer, configuring it for expire after |
| (value) timeout (which is a combination of the WDP0 |
| through WDP3 bits). |
| |
| This function is derived from <avr/wdt.h> but enables only |
| the interrupt bit (WDIE), rather than the reset bit (WDE). |
| |
| Can't find it documented but the WDT, once enabled, |
| rolls over and fires a new interrupt each time. |
| |
| See also the symbolic constants WDTO_15MS et al. |
| |
| Updated to match avr-libc 2.0.0 |
| */ |
| |
| #if defined( portUSE_WDTO) |
| |
| static __inline__ |
| __attribute__ ((__always_inline__)) |
| void wdt_interrupt_enable (const uint8_t value) |
| { |
| if (_SFR_IO_REG_P (_WD_CONTROL_REG)) |
| { |
| __asm__ __volatile__ ( |
| "in __tmp_reg__,__SREG__" "\n\t" |
| "cli" "\n\t" |
| "wdr" "\n\t" |
| "out %0, %1" "\n\t" |
| "out __SREG__,__tmp_reg__" "\n\t" |
| "out %0, %2" "\n\t" |
| : /* no outputs */ |
| : "I" (_SFR_IO_ADDR(_WD_CONTROL_REG)), |
| "r" ((uint8_t)(_BV(_WD_CHANGE_BIT) | _BV(WDE))), |
| "r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | |
| _BV(WDIF) | _BV(WDIE) | (value & 0x07)) ) |
| : "r0" |
| ); |
| } |
| else |
| { |
| __asm__ __volatile__ ( |
| "in __tmp_reg__,__SREG__" "\n\t" |
| "cli" "\n\t" |
| "wdr" "\n\t" |
| "sts %0, %1" "\n\t" |
| "out __SREG__,__tmp_reg__" "\n\t" |
| "sts %0, %2" "\n\t" |
| : /* no outputs */ |
| : "n" (_SFR_MEM_ADDR(_WD_CONTROL_REG)), |
| "r" ((uint8_t)(_BV(_WD_CHANGE_BIT) | _BV(WDE))), |
| "r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | |
| _BV(WDIF) | _BV(WDIE) | (value & 0x07)) ) |
| : "r0" |
| ); |
| } |
| } |
| #endif |
| |
| /*-----------------------------------------------------------*/ |
| /** |
| Enable the watchdog timer, configuring it for expire after |
| (value) timeout (which is a combination of the WDP0 |
| through WDP3 bits). |
| |
| This function is derived from <avr/wdt.h> but enables both |
| the reset bit (WDE), and the interrupt bit (WDIE). |
| |
| This will ensure that if the interrupt is not serviced |
| before the second timeout, the AVR will reset. |
| |
| Servicing the interrupt automatically clears it, |
| and ensures the AVR does not reset. |
| |
| Can't find it documented but the WDT, once enabled, |
| rolls over and fires a new interrupt each time. |
| |
| See also the symbolic constants WDTO_15MS et al. |
| |
| Updated to match avr-libc 2.0.0 |
| */ |
| |
| #if defined( portUSE_WDTO) |
| |
| static __inline__ |
| __attribute__ ((__always_inline__)) |
| void wdt_interrupt_reset_enable (const uint8_t value) |
| { |
| if (_SFR_IO_REG_P (_WD_CONTROL_REG)) |
| { |
| __asm__ __volatile__ ( |
| "in __tmp_reg__,__SREG__" "\n\t" |
| "cli" "\n\t" |
| "wdr" "\n\t" |
| "out %0, %1" "\n\t" |
| "out __SREG__,__tmp_reg__" "\n\t" |
| "out %0, %2" "\n\t" |
| : /* no outputs */ |
| : "I" (_SFR_IO_ADDR(_WD_CONTROL_REG)), |
| "r" ((uint8_t)(_BV(_WD_CHANGE_BIT) | _BV(WDE))), |
| "r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | |
| _BV(WDIF) | _BV(WDIE) | _BV(WDE) | (value & 0x07)) ) |
| : "r0" |
| ); |
| } |
| else |
| { |
| __asm__ __volatile__ ( |
| "in __tmp_reg__,__SREG__" "\n\t" |
| "cli" "\n\t" |
| "wdr" "\n\t" |
| "sts %0, %1" "\n\t" |
| "out __SREG__,__tmp_reg__" "\n\t" |
| "sts %0, %2" "\n\t" |
| : /* no outputs */ |
| : "n" (_SFR_MEM_ADDR(_WD_CONTROL_REG)), |
| "r" ((uint8_t)(_BV(_WD_CHANGE_BIT) | _BV(WDE))), |
| "r" ((uint8_t) ((value & 0x08 ? _WD_PS3_MASK : 0x00) | |
| _BV(WDIF) | _BV(WDIE) | _BV(WDE) | (value & 0x07)) ) |
| : "r0" |
| ); |
| } |
| } |
| #endif |
| |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * 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 (__zero_reg__) as the compiler expects it to be thus, however |
| * some of the math routines make use of R1. |
| * |
| * r0 is set to __tmp_reg__ as the compiler expects it to be thus. |
| * |
| * #if defined(__AVR_HAVE_RAMPZ__) |
| * #define __RAMPZ__ 0x3B |
| * #endif |
| * |
| * #if defined(__AVR_3_BYTE_PC__) |
| * #define __EIND__ 0x3C |
| * #endif |
| * |
| * The interrupts will have been disabled during the call to portSAVE_CONTEXT() |
| * so we need not worry about reading/writing to the stack pointer. |
| */ |
| #if defined(__AVR_3_BYTE_PC__) && defined(__AVR_HAVE_RAMPZ__) |
| /* 3-Byte PC Save with RAMPZ */ |
| #define portSAVE_CONTEXT() \ |
| __asm__ __volatile__ ( "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SREG__ \n\t" \ |
| "cli \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, 0x3B \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, 0x3C \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "push __zero_reg__ \n\t" \ |
| "clr __zero_reg__ \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" \ |
| "lds r26, pxCurrentTCB \n\t" \ |
| "lds r27, pxCurrentTCB + 1 \n\t" \ |
| "in __tmp_reg__, __SP_L__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SP_H__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| ); |
| #elif defined(__AVR_HAVE_RAMPZ__) |
| /* 2-Byte PC Save with RAMPZ */ |
| #define portSAVE_CONTEXT() \ |
| __asm__ __volatile__ ( "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SREG__ \n\t" \ |
| "cli \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, 0x3B \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "push __zero_reg__ \n\t" \ |
| "clr __zero_reg__ \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" \ |
| "lds r26, pxCurrentTCB \n\t" \ |
| "lds r27, pxCurrentTCB + 1 \n\t" \ |
| "in __tmp_reg__, __SP_L__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SP_H__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| ); |
| #else |
| /* 2-Byte PC Save */ |
| #define portSAVE_CONTEXT() \ |
| __asm__ __volatile__ ( "push __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SREG__ \n\t" \ |
| "cli \n\t" \ |
| "push __tmp_reg__ \n\t" \ |
| "push __zero_reg__ \n\t" \ |
| "clr __zero_reg__ \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" \ |
| "lds r26, pxCurrentTCB \n\t" \ |
| "lds r27, pxCurrentTCB + 1 \n\t" \ |
| "in __tmp_reg__, __SP_L__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| "in __tmp_reg__, __SP_H__ \n\t" \ |
| "st x+, __tmp_reg__ \n\t" \ |
| ); |
| #endif |
| |
| /* |
| * Opposite to portSAVE_CONTEXT(). Interrupts will have been disabled during |
| * the context save so we can write to the stack pointer. |
| */ |
| #if defined(__AVR_3_BYTE_PC__) && defined(__AVR_HAVE_RAMPZ__) |
| /* 3-Byte PC Restore with RAMPZ */ |
| #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 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 __zero_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out 0x3C, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out 0x3B, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out __SREG__, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| ); |
| #elif defined(__AVR_HAVE_RAMPZ__) |
| /* 2-Byte PC Restore with RAMPZ */ |
| #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 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 __zero_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out 0x3B, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out __SREG__, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| ); |
| #else |
| /* 2-Byte PC Restore */ |
| #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 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 __zero_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| "out __SREG__, __tmp_reg__ \n\t" \ |
| "pop __tmp_reg__ \n\t" \ |
| ); |
| #endif |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * Perform hardware setup to enable ticks from relevant Timer. |
| */ |
| static void prvSetupTimerInterrupt( void ); |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * See header file for description. |
| */ |
| StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters ) |
| { |
| uint16_t usAddress; |
| /* Simulate how the stack would look after a call to vPortYield() generated by |
| the compiler. */ |
| |
| /* The start of the task code will be popped off the stack last, so place |
| it on first. */ |
| usAddress = ( uint16_t ) pxCode; |
| *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff ); |
| pxTopOfStack--; |
| |
| usAddress >>= 8; |
| *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff ); |
| pxTopOfStack--; |
| |
| #if defined(__AVR_3_BYTE_PC__) |
| /* The AVR ATmega2560/ATmega2561 have 256KBytes of program memory and a 17-bit |
| * program counter. When a code address is stored on the stack, it takes 3 bytes |
| * instead of 2 for the other ATmega* chips. |
| * |
| * Store 0 as the top byte since we force all task routines to the bottom 128K |
| * of flash. We do this by using the .lowtext label in the linker script. |
| * |
| * In order to do this properly, we would need to get a full 3-byte pointer to |
| * pxCode. That requires a change to GCC. Not likely to happen any time soon. |
| */ |
| *pxTopOfStack = 0; |
| pxTopOfStack--; |
| #endif |
| |
| /* 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 = ( StackType_t ) 0x00; /* R0 */ |
| pxTopOfStack--; |
| *pxTopOfStack = portFLAGS_INT_ENABLED; |
| pxTopOfStack--; |
| |
| #if defined(__AVR_3_BYTE_PC__) |
| /* If we have an ATmega256x, we are also saving the EIND register. |
| * We should default to 0. |
| */ |
| *pxTopOfStack = ( StackType_t ) 0x00; /* EIND */ |
| pxTopOfStack--; |
| #endif |
| |
| #if defined(__AVR_HAVE_RAMPZ__) |
| /* We are saving the RAMPZ register. |
| * We should default to 0. |
| */ |
| *pxTopOfStack = ( StackType_t ) 0x00; /* RAMPZ */ |
| pxTopOfStack--; |
| #endif |
| |
| /* Now the remaining registers. The compiler expects R1 to be 0. */ |
| *pxTopOfStack = ( StackType_t ) 0x00; /* R1 */ |
| |
| /* Leave R2 - R23 untouched */ |
| pxTopOfStack -= 23; |
| |
| /* Place the parameter on the stack in the expected location. */ |
| usAddress = ( uint16_t ) pvParameters; |
| *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff ); |
| pxTopOfStack--; |
| |
| usAddress >>= 8; |
| *pxTopOfStack = ( StackType_t ) ( usAddress & ( uint16_t ) 0x00ff ); |
| |
| /* Leave register R26 - R31 untouched */ |
| pxTopOfStack -= 7; |
| |
| return pxTopOfStack; |
| } |
| /*-----------------------------------------------------------*/ |
| |
| BaseType_t xPortStartScheduler( void ) |
| { |
| /* Setup the relevant timer 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 ATmega port will get stopped. */ |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * Manual context switch. The first thing we do is save the registers so we |
| * can use a naked attribute. |
| */ |
| void vPortYield( void ) __attribute__ ( ( hot, flatten, naked ) ); |
| void vPortYield( void ) |
| { |
| portSAVE_CONTEXT(); |
| vTaskSwitchContext(); |
| portRESTORE_CONTEXT(); |
| |
| __asm__ __volatile__ ( "ret" ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * Manual context switch callable from ISRs. The first thing we do is save |
| * the registers so we can use a naked attribute. |
| */ |
| void vPortYieldFromISR(void) __attribute__ ( ( hot, flatten, naked ) ); |
| void vPortYieldFromISR(void) |
| { |
| portSAVE_CONTEXT(); |
| vTaskSwitchContext(); |
| portRESTORE_CONTEXT(); |
| |
| __asm__ __volatile__ ( "reti" ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * 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__ ( ( hot, flatten, naked ) ); |
| void vPortYieldFromTick( void ) |
| { |
| portSAVE_CONTEXT(); |
| if( xTaskIncrementTick() != pdFALSE ) |
| { |
| vTaskSwitchContext(); |
| } |
| portRESTORE_CONTEXT(); |
| |
| __asm__ __volatile__ ( "ret" ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| #if defined(portUSE_WDTO) |
| /* |
| * Setup WDT to generate a tick interrupt. |
| */ |
| void prvSetupTimerInterrupt( void ) |
| { |
| /* reset watchdog */ |
| wdt_reset(); |
| |
| /* set up WDT Interrupt (rather than the WDT Reset). */ |
| wdt_interrupt_enable( portUSE_WDTO ); |
| } |
| |
| #elif defined (portUSE_TIMER0) |
| /* |
| * Setup Timer0 compare match A to generate a tick interrupt. |
| */ |
| static void prvSetupTimerInterrupt( void ) |
| { |
| uint32_t ulCompareMatch; |
| uint8_t ucLowByte; |
| |
| /* Using 8bit Timer0 to generate the tick. Correct fuses must be |
| selected for the configCPU_CLOCK_HZ clock.*/ |
| |
| ulCompareMatch = configCPU_CLOCK_HZ / configTICK_RATE_HZ; |
| |
| /* We only have 8 bits so have to scale 1024 to get our required tick rate. */ |
| ulCompareMatch /= portCLOCK_PRESCALER; |
| |
| /* Adjust for correct value. */ |
| ulCompareMatch -= ( uint32_t ) 1; |
| |
| /* Setup compare match value for compare match A. Interrupts are disabled |
| before this is called so we need not worry here. */ |
| ucLowByte = ( uint8_t ) ( ulCompareMatch & ( uint32_t ) 0xff ); |
| portOCRL = ucLowByte; |
| |
| /* Setup clock source and compare match behaviour. */ |
| portTCCRa = portCLEAR_COUNTER_ON_MATCH; |
| portTCCRb = portPRESCALE_1024; |
| |
| |
| /* Enable the interrupt - this is okay as interrupt are currently globally disabled. */ |
| ucLowByte = portTIMSK; |
| ucLowByte |= portCOMPARE_MATCH_A_INTERRUPT_ENABLE; |
| portTIMSK = ucLowByte; |
| } |
| |
| #endif |
| |
| /*-----------------------------------------------------------*/ |
| |
| #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. |
| * |
| * use ISR_NOBLOCK where there is an important timer running, that should preempt the scheduler. |
| * |
| */ |
| ISR(portSCHEDULER_ISR, ISR_NAKED) __attribute__ ((hot, flatten)); |
| /* ISR(portSCHEDULER_ISR, ISR_NAKED ISR_NOBLOCK) __attribute__ ((hot, flatten)); |
| */ |
| ISR(portSCHEDULER_ISR) |
| { |
| 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(); |
| * |
| * use ISR_NOBLOCK where there is an important timer running, that should preempt the scheduler. |
| */ |
| ISR(portSCHEDULER_ISR) __attribute__ ((hot, flatten)); |
| /* ISR(portSCHEDULER_ISR, ISR_NOBLOCK) __attribute__ ((hot, flatten)); |
| */ |
| ISR(portSCHEDULER_ISR) |
| { |
| xTaskIncrementTick(); |
| } |
| #endif |
| |
| |
