| /* |
| * 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 |
| * |
| */ |
| |
| /* GCC/HCS12 port by Jefferson L Smith, 2005 */ |
| |
| /* Scheduler includes. */ |
| #include "FreeRTOS.h" |
| #include "task.h" |
| |
| /* Port includes */ |
| #include <sys/ports_def.h> |
| |
| /*----------------------------------------------------------- |
| * Implementation of functions defined in portable.h for the HCS12 port. |
| *----------------------------------------------------------*/ |
| |
| |
| /* |
| * Configure a timer to generate the RTOS tick at the frequency specified |
| * within FreeRTOSConfig.h. |
| */ |
| static void prvSetupTimerInterrupt( void ); |
| |
| /* NOTE: Interrupt service routines must be in non-banked memory - as does the |
| scheduler startup function. */ |
| #define ATTR_NEAR __attribute__((near)) |
| |
| /* Manual context switch function. This is the SWI ISR. */ |
| // __attribute__((interrupt)) |
| void ATTR_NEAR vPortYield( void ); |
| |
| /* Tick context switch function. This is the timer ISR. */ |
| // __attribute__((interrupt)) |
| void ATTR_NEAR vPortTickInterrupt( void ); |
| |
| /* Function in non-banked memory which actually switches to first task. */ |
| BaseType_t ATTR_NEAR xStartSchedulerNear( void ); |
| |
| /* Calls to portENTER_CRITICAL() can be nested. When they are nested the |
| critical section should not be left (i.e. interrupts should not be re-enabled) |
| until the nesting depth reaches 0. This variable simply tracks the nesting |
| depth. Each task maintains it's own critical nesting depth variable so |
| uxCriticalNesting is saved and restored from the task stack during a context |
| switch. */ |
| volatile UBaseType_t uxCriticalNesting = 0x80; // un-initialized |
| |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * See header file for description. |
| */ |
| StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters ) |
| { |
| |
| |
| /* Setup the initial stack of the task. The stack is set exactly as |
| expected by the portRESTORE_CONTEXT() macro. In this case the stack as |
| expected by the HCS12 RTI instruction. */ |
| |
| |
| /* The address of the task function is placed in the stack byte at a time. */ |
| *pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pxCode) ) + 1 ); |
| *--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pxCode) ) + 0 ); |
| |
| /* Next are all the registers that form part of the task context. */ |
| |
| /* Y register */ |
| *--pxTopOfStack = ( StackType_t ) 0xff; |
| *--pxTopOfStack = ( StackType_t ) 0xee; |
| |
| /* X register */ |
| *--pxTopOfStack = ( StackType_t ) 0xdd; |
| *--pxTopOfStack = ( StackType_t ) 0xcc; |
| |
| /* A register contains parameter high byte. */ |
| *--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pvParameters) ) + 0 ); |
| |
| /* B register contains parameter low byte. */ |
| *--pxTopOfStack = ( StackType_t ) *( ((StackType_t *) (&pvParameters) ) + 1 ); |
| |
| /* CCR: Note that when the task starts interrupts will be enabled since |
| "I" bit of CCR is cleared */ |
| *--pxTopOfStack = ( StackType_t ) 0x80; // keeps Stop disabled (MCU default) |
| |
| /* tmp softregs used by GCC. Values right now don't matter. */ |
| __asm("\n\ |
| movw _.frame, 2,-%0 \n\ |
| movw _.tmp, 2,-%0 \n\ |
| movw _.z, 2,-%0 \n\ |
| movw _.xy, 2,-%0 \n\ |
| ;movw _.d2, 2,-%0 \n\ |
| ;movw _.d1, 2,-%0 \n\ |
| ": "=A"(pxTopOfStack) : "0"(pxTopOfStack) ); |
| |
| #ifdef BANKED_MODEL |
| /* The page of the task. */ |
| *--pxTopOfStack = 0x30; // can only directly start in PPAGE 0x30 |
| #endif |
| |
| /* The critical nesting depth is initialised with 0 (meaning not in |
| a critical section). */ |
| *--pxTopOfStack = ( StackType_t ) 0x00; |
| |
| |
| return pxTopOfStack; |
| } |
| /*-----------------------------------------------------------*/ |
| |
| void vPortEndScheduler( void ) |
| { |
| /* It is unlikely that the HCS12 port will get stopped. */ |
| } |
| /*-----------------------------------------------------------*/ |
| |
| static void prvSetupTimerInterrupt( void ) |
| { |
| /* Enable hardware RTI timer */ |
| /* Ignores configTICK_RATE_HZ */ |
| RTICTL = 0x50; // 16 MHz xtal: 976.56 Hz, 1024mS |
| CRGINT |= 0x80; // RTIE |
| } |
| /*-----------------------------------------------------------*/ |
| |
| BaseType_t xPortStartScheduler( void ) |
| { |
| /* xPortStartScheduler() does not start the scheduler directly because |
| the header file containing the xPortStartScheduler() prototype is part |
| of the common kernel code, and therefore cannot use the CODE_SEG pragma. |
| Instead it simply calls the locally defined xNearStartScheduler() - |
| which does use the CODE_SEG pragma. */ |
| |
| int16_t register d; |
| __asm ("jmp xStartSchedulerNear ; will never return": "=d"(d)); |
| return d; |
| } |
| /*-----------------------------------------------------------*/ |
| |
| BaseType_t xStartSchedulerNear( void ) |
| { |
| /* Configure the timer that will generate the RTOS tick. Interrupts are |
| disabled when this function is called. */ |
| prvSetupTimerInterrupt(); |
| |
| /* Restore the context of the first task. */ |
| portRESTORE_CONTEXT(); |
| |
| portISR_TAIL(); |
| |
| /* Should not get here! */ |
| return pdFALSE; |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * Context switch functions. These are interrupt service routines. |
| */ |
| |
| /* |
| * Manual context switch forced by calling portYIELD(). This is the SWI |
| * handler. |
| */ |
| void vPortYield( void ) |
| { |
| portISR_HEAD(); |
| /* NOTE: This is the trap routine (swi) although not defined as a trap. |
| It will fill the stack the same way as an ISR in order to mix preemtion |
| and cooperative yield. */ |
| |
| portSAVE_CONTEXT(); |
| vTaskSwitchContext(); |
| portRESTORE_CONTEXT(); |
| |
| portISR_TAIL(); |
| } |
| /*-----------------------------------------------------------*/ |
| |
| /* |
| * RTOS tick interrupt service routine. If the cooperative scheduler is |
| * being used then this simply increments the tick count. If the |
| * preemptive scheduler is being used a context switch can occur. |
| */ |
| void vPortTickInterrupt( void ) |
| { |
| portISR_HEAD(); |
| |
| /* Clear tick timer flag */ |
| CRGFLG = 0x80; |
| |
| #if configUSE_PREEMPTION == 1 |
| { |
| /* A context switch might happen so save the context. */ |
| portSAVE_CONTEXT(); |
| |
| /* Increment the tick ... */ |
| if( xTaskIncrementTick() != pdFALSE ) |
| { |
| /* A context switch is necessary. */ |
| vTaskSwitchContext(); |
| } |
| |
| /* Restore the context of a task - which may be a different task |
| to that interrupted. */ |
| portRESTORE_CONTEXT(); |
| } |
| #else |
| { |
| xTaskIncrementTick(); |
| } |
| #endif |
| |
| portISR_TAIL(); |
| } |