| /* |
| * FreeRTOS Kernel <DEVELOPMENT BRANCH> |
| * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. 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 |
| * |
| */ |
| |
| /* |
| Changes from V1.00: |
| |
| + Call to taskYIELD() from within tick ISR has been replaced by the more |
| efficient portSWITCH_CONTEXT(). |
| + ISR function definitions renamed to include the prv prefix. |
| |
| Changes from V2.6.1 |
| |
| + Replaced the sUsingPreemption variable with the configUSE_PREEMPTION |
| macro to be consistent with the later ports. |
| */ |
| |
| /*----------------------------------------------------------- |
| * Implementation of functions defined in portable.h for the Flashlite 186 |
| * port. |
| *----------------------------------------------------------*/ |
| |
| #include <dos.h> |
| #include <stdlib.h> |
| #include <setjmp.h> |
| |
| #include "FreeRTOS.h" |
| #include "task.h" |
| #include "portasm.h" |
| |
| /*lint -e950 Non ANSI reserved words okay in this file only. */ |
| |
| #define portTIMER_EOI_TYPE ( 8 ) |
| #define portRESET_PIC() portOUTPUT_WORD( ( uint16_t ) 0xff22, portTIMER_EOI_TYPE ) |
| #define portTIMER_INT_NUMBER 0x12 |
| |
| #define portTIMER_1_CONTROL_REGISTER ( ( uint16_t ) 0xff5e ) |
| #define portTIMER_0_CONTROL_REGISTER ( ( uint16_t ) 0xff56 ) |
| #define portTIMER_INTERRUPT_ENABLE ( ( uint16_t ) 0x2000 ) |
| |
| /* Setup the hardware to generate the required tick frequency. */ |
| static void prvSetTickFrequency( uint32_t ulTickRateHz ); |
| |
| /* Set the hardware back to the state as per before the scheduler started. */ |
| static void prvExitFunction( void ); |
| |
| /* The ISR used depends on whether the preemptive or cooperative scheduler |
| is being used. */ |
| #if( configUSE_PREEMPTION == 1 ) |
| /* Tick service routine used by the scheduler when preemptive scheduling is |
| being used. */ |
| static void __interrupt __far prvPreemptiveTick( void ); |
| #else |
| /* Tick service routine used by the scheduler when cooperative scheduling is |
| being used. */ |
| static void __interrupt __far prvNonPreemptiveTick( void ); |
| #endif |
| |
| /* Trap routine used by taskYIELD() to manually cause a context switch. */ |
| static void __interrupt __far prvYieldProcessor( void ); |
| |
| /*lint -e956 File scopes necessary here. */ |
| |
| /* Set true when the vectors are set so the scheduler will service the tick. */ |
| static BaseType_t xSchedulerRunning = pdFALSE; |
| |
| /* Points to the original routine installed on the vector we use for manual |
| context switches. This is then used to restore the original routine during |
| prvExitFunction(). */ |
| static void ( __interrupt __far *pxOldSwitchISR )(); |
| |
| /* Used to restore the original DOS context when the scheduler is ended. */ |
| static jmp_buf xJumpBuf; |
| |
| /*lint +e956 */ |
| |
| /*-----------------------------------------------------------*/ |
| BaseType_t xPortStartScheduler( void ) |
| { |
| /* This is called with interrupts already disabled. */ |
| |
| /* Remember what was on the interrupts we are going to use |
| so we can put them back later if required. */ |
| pxOldSwitchISR = _dos_getvect( portSWITCH_INT_NUMBER ); |
| |
| /* Put our manual switch (yield) function on a known |
| vector. */ |
| _dos_setvect( portSWITCH_INT_NUMBER, prvYieldProcessor ); |
| |
| #if( configUSE_PREEMPTION == 1 ) |
| { |
| /* Put our tick switch function on the timer interrupt. */ |
| _dos_setvect( portTIMER_INT_NUMBER, prvPreemptiveTick ); |
| } |
| #else |
| { |
| /* We want the timer interrupt to just increment the tick count. */ |
| _dos_setvect( portTIMER_INT_NUMBER, prvNonPreemptiveTick ); |
| } |
| #endif |
| |
| prvSetTickFrequency( configTICK_RATE_HZ ); |
| |
| /* Clean up function if we want to return to DOS. */ |
| if( setjmp( xJumpBuf ) != 0 ) |
| { |
| prvExitFunction(); |
| xSchedulerRunning = pdFALSE; |
| } |
| else |
| { |
| xSchedulerRunning = pdTRUE; |
| |
| /* Kick off the scheduler by setting up the context of the first task. */ |
| portFIRST_CONTEXT(); |
| } |
| |
| return xSchedulerRunning; |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* The ISR used depends on whether the preemptive or cooperative scheduler |
| is being used. */ |
| #if( configUSE_PREEMPTION == 1 ) |
| static void __interrupt __far prvPreemptiveTick( void ) |
| { |
| /* Get the scheduler to update the task states following the tick. */ |
| if( xTaskIncrementTick() != pdFALSE ) |
| { |
| /* Switch in the context of the next task to be run. */ |
| portSWITCH_CONTEXT(); |
| } |
| |
| /* Reset the PIC ready for the next time. */ |
| portRESET_PIC(); |
| } |
| #else |
| static void __interrupt __far prvNonPreemptiveTick( void ) |
| { |
| /* Same as preemptive tick, but the cooperative scheduler is being used |
| so we don't have to switch in the context of the next task. */ |
| xTaskIncrementTick(); |
| portRESET_PIC(); |
| } |
| #endif |
| /*-----------------------------------------------------------*/ |
| |
| static void __interrupt __far prvYieldProcessor( void ) |
| { |
| /* Switch in the context of the next task to be run. */ |
| portSWITCH_CONTEXT(); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vPortEndScheduler( void ) |
| { |
| /* Jump back to the processor state prior to starting the |
| scheduler. This means we are not going to be using a |
| task stack frame so the task can be deleted. */ |
| longjmp( xJumpBuf, 1 ); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| static void prvExitFunction( void ) |
| { |
| const uint16_t usTimerDisable = 0x0000; |
| uint16_t usTimer0Control; |
| |
| /* Interrupts should be disabled here anyway - but no |
| harm in making sure. */ |
| portDISABLE_INTERRUPTS(); |
| if( xSchedulerRunning == pdTRUE ) |
| { |
| /* Put back the switch interrupt routines that was in place |
| before the scheduler started. */ |
| _dos_setvect( portSWITCH_INT_NUMBER, pxOldSwitchISR ); |
| } |
| |
| /* Disable the timer used for the tick to ensure the scheduler is |
| not called before restoring interrupts. There was previously nothing |
| on this timer so there is no old ISR to restore. */ |
| portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerDisable ); |
| |
| /* Restart the DOS tick. */ |
| usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER ); |
| usTimer0Control |= portTIMER_INTERRUPT_ENABLE; |
| portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control ); |
| |
| |
| portENABLE_INTERRUPTS(); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| static void prvSetTickFrequency( uint32_t ulTickRateHz ) |
| { |
| const uint16_t usMaxCountRegister = 0xff5a; |
| const uint16_t usTimerPriorityRegister = 0xff32; |
| const uint16_t usTimerEnable = 0xC000; |
| const uint16_t usRetrigger = 0x0001; |
| const uint16_t usTimerHighPriority = 0x0000; |
| uint16_t usTimer0Control; |
| |
| /* ( CPU frequency / 4 ) / clock 2 max count [inpw( 0xff62 ) = 7] */ |
| |
| const uint32_t ulClockFrequency = ( uint32_t ) 0x7f31a0UL; |
| |
| uint32_t ulTimerCount = ulClockFrequency / ulTickRateHz; |
| |
| portOUTPUT_WORD( portTIMER_1_CONTROL_REGISTER, usTimerEnable | portTIMER_INTERRUPT_ENABLE | usRetrigger ); |
| portOUTPUT_WORD( usMaxCountRegister, ( uint16_t ) ulTimerCount ); |
| portOUTPUT_WORD( usTimerPriorityRegister, usTimerHighPriority ); |
| |
| /* Stop the DOS tick - don't do this if you want to maintain a TOD clock. */ |
| usTimer0Control = portINPUT_WORD( portTIMER_0_CONTROL_REGISTER ); |
| usTimer0Control &= ~portTIMER_INTERRUPT_ENABLE; |
| portOUTPUT_WORD( portTIMER_0_CONTROL_REGISTER, usTimer0Control ); |
| } |
| |
| |
| /*lint +e950 */ |