/* * FreeRTOS Kernel * 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 * */ /*----------------------------------------------------------- * Implementation of functions defined in portable.h for the RX600 port. *----------------------------------------------------------*/ /* Scheduler includes. */ #include "FreeRTOS.h" #include "task.h" /* Library includes. */ #include "string.h" /* Hardware specifics. */ #include "iodefine.h" /*-----------------------------------------------------------*/ /* Tasks should start with interrupts enabled and in Supervisor mode, therefore * PSW is set with U and I set, and PM and IPL clear. */ #define portINITIAL_PSW ( ( StackType_t ) 0x00030000 ) #define portINITIAL_FPSW ( ( StackType_t ) 0x00000100 ) /*-----------------------------------------------------------*/ /* The following lines are to ensure vSoftwareInterruptEntry can be referenced, * and therefore installed in the vector table, when the FreeRTOS code is built * as a library. */ extern BaseType_t vSoftwareInterruptEntry; const BaseType_t * p_vSoftwareInterruptEntry = &vSoftwareInterruptEntry; /*-----------------------------------------------------------*/ /* * Function to start the first task executing - written in asm code as direct * access to registers is required. */ static void prvStartFirstTask( void ); /* * Software interrupt handler. Performs the actual context switch (saving and * restoring of registers). Written in asm code as direct register access is * required. */ static void prvYieldHandler( void ); /* * The entry point for the software interrupt handler. This is the function * that calls the inline asm function prvYieldHandler(). It is installed in * the vector table, but the code that installs it is in prvYieldHandler rather * than using a #pragma. */ void vSoftwareInterruptISR( void ); /*-----------------------------------------------------------*/ /* This is accessed by the inline assembler functions so is file scope for * convenience. */ extern void * pxCurrentTCB; extern void vTaskSwitchContext( void ); /*-----------------------------------------------------------*/ /* * See header file for description. */ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack, TaskFunction_t pxCode, void * pvParameters ) { /* R0 is not included as it is the stack pointer. */ *pxTopOfStack = 0x00; pxTopOfStack--; *pxTopOfStack = portINITIAL_PSW; pxTopOfStack--; *pxTopOfStack = ( StackType_t ) pxCode; /* When debugging it can be useful if every register is set to a known * value. Otherwise code space can be saved by just setting the registers * that need to be set. */ #ifdef USE_FULL_REGISTER_INITIALISATION { pxTopOfStack--; *pxTopOfStack = 0xffffffff; /* r15. */ pxTopOfStack--; *pxTopOfStack = 0xeeeeeeee; pxTopOfStack--; *pxTopOfStack = 0xdddddddd; pxTopOfStack--; *pxTopOfStack = 0xcccccccc; pxTopOfStack--; *pxTopOfStack = 0xbbbbbbbb; pxTopOfStack--; *pxTopOfStack = 0xaaaaaaaa; pxTopOfStack--; *pxTopOfStack = 0x99999999; pxTopOfStack--; *pxTopOfStack = 0x88888888; pxTopOfStack--; *pxTopOfStack = 0x77777777; pxTopOfStack--; *pxTopOfStack = 0x66666666; pxTopOfStack--; *pxTopOfStack = 0x55555555; pxTopOfStack--; *pxTopOfStack = 0x44444444; pxTopOfStack--; *pxTopOfStack = 0x33333333; pxTopOfStack--; *pxTopOfStack = 0x22222222; pxTopOfStack--; } #else /* ifdef USE_FULL_REGISTER_INITIALISATION */ { pxTopOfStack -= 15; } #endif /* ifdef USE_FULL_REGISTER_INITIALISATION */ *pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */ pxTopOfStack--; *pxTopOfStack = portINITIAL_FPSW; pxTopOfStack--; *pxTopOfStack = 0x12345678; /* Accumulator. */ pxTopOfStack--; *pxTopOfStack = 0x87654321; /* Accumulator. */ return pxTopOfStack; } /*-----------------------------------------------------------*/ BaseType_t xPortStartScheduler( void ) { extern void vApplicationSetupTimerInterrupt( void ); /* Use pxCurrentTCB just so it does not get optimised away. */ if( pxCurrentTCB != NULL ) { /* Call an application function to set up the timer that will generate the * tick interrupt. This way the application can decide which peripheral to * use. A demo application is provided to show a suitable example. */ vApplicationSetupTimerInterrupt(); /* Enable the software interrupt. */ _IEN( _ICU_SWINT ) = 1; /* Ensure the software interrupt is clear. */ _IR( _ICU_SWINT ) = 0; /* Ensure the software interrupt is set to the kernel priority. */ _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY; /* Start the first task. */ prvStartFirstTask(); } /* Just to make sure the function is not optimised away. */ ( void ) vSoftwareInterruptISR(); /* Should not get here. */ return pdFAIL; } /*-----------------------------------------------------------*/ #pragma inline_asm prvStartFirstTask static void prvStartFirstTask( void ) { /* When starting the scheduler there is nothing that needs moving to the * interrupt stack because the function is not called from an interrupt. * Just ensure the current stack is the user stack. */ SETPSW U /* Obtain the location of the stack associated with which ever task * pxCurrentTCB is currently pointing to. */ MOV.L # _pxCurrentTCB, R15 MOV.L[ R15 ], R15 MOV.L[ R15 ], R0 /* Restore the registers from the stack of the task pointed to by * pxCurrentTCB. */ POP R15 MVTACLO R15 /* Accumulator low 32 bits. */ POP R15 MVTACHI R15 /* Accumulator high 32 bits. */ POP R15 MVTC R15, FPSW /* Floating point status word. */ POPM R1 - R15 /* R1 to R15 - R0 is not included as it is the SP. */ RTE /* This pops the remaining registers. */ NOP NOP } /*-----------------------------------------------------------*/ #pragma interrupt ( vTickISR( vect = _VECT( configTICK_VECTOR ), enable ) ) void vTickISR( void ) { /* Increment the tick, and perform any processing the new tick value * necessitates. */ set_ipl( configMAX_SYSCALL_INTERRUPT_PRIORITY ); { if( xTaskIncrementTick() != pdFALSE ) { taskYIELD(); } } set_ipl( configKERNEL_INTERRUPT_PRIORITY ); } /*-----------------------------------------------------------*/ void vSoftwareInterruptISR( void ) { prvYieldHandler(); } /*-----------------------------------------------------------*/ #pragma inline_asm prvYieldHandler static void prvYieldHandler( void ) { /* Re-enable interrupts. */ SETPSW I /* Move the data that was automatically pushed onto the interrupt stack when * the interrupt occurred from the interrupt stack to the user stack. * * R15 is saved before it is clobbered. */ PUSH.L R15 /* Read the user stack pointer. */ MVFC USP, R15 /* Move the address down to the data being moved. */ SUB # 12, R15 MVTC R15, USP /* Copy the data across. */ MOV.L[ R0 ], [ R15 ]; R15 MOV.L 4[ R0 ], 4[ R15 ]; PC MOV.L 8[ R0 ], 8[ R15 ]; PSW /* Move the interrupt stack pointer to its new correct position. */ ADD # 12, R0 /* All the rest of the registers are saved directly to the user stack. */ SETPSW U /* Save the rest of the general registers (R15 has been saved already). */ PUSHM R1 - R14 /* Save the FPSW and accumulator. */ MVFC FPSW, R15 PUSH.L R15 MVFACHI R15 PUSH.L R15 MVFACMI R15; Middle order word. SHLL # 16, R15; Shifted left as it is restored to the low order word. PUSH.L R15 /* Save the stack pointer to the TCB. */ MOV.L # _pxCurrentTCB, R15 MOV.L[ R15 ], R15 MOV.L R0, [ R15 ] /* Ensure the interrupt mask is set to the syscall priority while the kernel * structures are being accessed. */ MVTIPL # configMAX_SYSCALL_INTERRUPT_PRIORITY /* Select the next task to run. */ BSR.A _vTaskSwitchContext /* Reset the interrupt mask as no more data structure access is required. */ MVTIPL # configKERNEL_INTERRUPT_PRIORITY /* Load the stack pointer of the task that is now selected as the Running * state task from its TCB. */ MOV.L # _pxCurrentTCB, R15 MOV.L[ R15 ], R15 MOV.L[ R15 ], R0 /* Restore the context of the new task. The PSW (Program Status Word) and * PC will be popped by the RTE instruction. */ POP R15 MVTACLO R15 POP R15 MVTACHI R15 POP R15 MVTC R15, FPSW POPM R1 - R15 RTE NOP NOP } /*-----------------------------------------------------------*/ void vPortEndScheduler( void ) { /* Not implemented in ports where there is nothing to return to. * Artificially force an assert. */ configASSERT( pxCurrentTCB == NULL ); /* The following line is just to prevent the symbol getting optimised away. */ ( void ) vTaskSwitchContext(); } /*-----------------------------------------------------------*/