8d9c3cc2b7
This is the ONLY way to be able to override ISRs stolen by the Arduino Runtime, such as Serial or USB device interrupts. This feature is needed so Arduino modules can be replaced and enhanced.
96 lines
3.1 KiB
C++
96 lines
3.1 KiB
C++
/**
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* Marlin 3D Printer Firmware
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* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/**
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* InterruptVectors_Due.cpp - This module relocates the Interrupt vector table to SRAM,
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* allowing to register new interrupt handlers at runtime. Specially valuable and needed
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* because Arduino runtime allocates some interrupt handlers that we NEED to override to
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* properly support extended functionality, as for example, USB host or USB device (MSD, MTP)
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* and custom serial port handlers, and we don't actually want to modify and/or recompile the
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* Arduino runtime. We just want to run as much as possible on Stock Arduino
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*
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* Copyright (c) 2017 Eduardo José Tagle. All right reserved
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*/
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#ifdef ARDUINO_ARCH_SAM
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#include "HAL_Due.h"
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#include "InterruptVectors_Due.h"
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/* The relocated Exception/Interrupt Table - Must be aligned to 128bytes,
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as bits 0-6 on VTOR register are reserved and must be set to 0 */
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__attribute__ ((aligned(128)))
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static DeviceVectors ram_tab = { NULL };
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/**
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* This function checks if the exception/interrupt table is already in SRAM or not.
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* If it is not, then it copies the ROM table to the SRAM and relocates the table
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* by reprogramming the NVIC registers
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*/
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static pfnISR_Handler* get_relocated_table_addr(void) {
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// Get the address of the interrupt/exception table
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uint32_t isrtab = SCB->VTOR;
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// If already relocated, we are done!
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if (isrtab >= IRAM0_ADDR)
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return (pfnISR_Handler*)isrtab;
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// Get the address of the table stored in FLASH
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const pfnISR_Handler* romtab = (const pfnISR_Handler*)isrtab;
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// Copy it to SRAM
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memcpy(&ram_tab, romtab, sizeof(ram_tab));
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// Disable global interrupts
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CRITICAL_SECTION_START;
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// Set the vector table base address to the SRAM copy
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SCB->VTOR = (uint32_t)(&ram_tab);
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// Reenable interrupts
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CRITICAL_SECTION_END;
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// Return the address of the table
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return (pfnISR_Handler*)(&ram_tab);
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}
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pfnISR_Handler install_isr(IRQn_Type irq, pfnISR_Handler newHandler) {
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// Get the address of the relocated table
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const pfnISR_Handler *isrtab = get_relocated_table_addr();
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// Disable global interrupts
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CRITICAL_SECTION_START;
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// Get the original handler
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pfnISR_Handler oldHandler = isrtab[irq + 16];
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// Install the new one
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isrtab[irq + 16] = newHandler;
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// Reenable interrupts
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CRITICAL_SECTION_END;
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// Return the original one
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return oldHandler;
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}
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#endif
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