/* * FreeRTOS Kernel V11.1.0 * 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 /*----------------------------------------------------------- * 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 /* if configUSE_PREEMPTION == 1 */ { xTaskIncrementTick(); } #endif /* if configUSE_PREEMPTION == 1 */ portISR_TAIL(); }