circuitpython/ports/samd/samd_isr.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Damien P. George
 *
 * 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.
 */

#include "samd_soc.h"

typedef void (*ISR)(void);

extern uint32_t _estack, _sidata, _sdata, _edata, _sbss, _ebss;

const ISR isr_vector[];
uint32_t systick_ms;

void Reset_Handler(void) __attribute__((naked));
void Reset_Handler(void) {
    // Set stack pointer
    #if __CORTEX_M >= 0x03
    __asm volatile ("ldr sp, =_estack");
    #else
    __asm volatile ("ldr r0, =_estack");
    __asm volatile ("mov sp, r0");
    #endif
    // Copy .data section from flash to RAM
    for (uint32_t *src = &_sidata, *dest = &_sdata; dest < &_edata;) {
        *dest++ = *src++;
    }
    // Zero out .bss section
    for (uint32_t *dest = &_sbss; dest < &_ebss;) {
        *dest++ = 0;
    }

    // When we get here: stack is initialised, bss is clear, data is copied

    #if __FPU_PRESENT == 1 && __FPU_USED == 1
    // Set CP10 and CP11 Full Access
    SCB->CPACR |= (3UL << 10 * 2) | (3UL << 11 * 2);
    #endif

    // SCB->VTOR
    *((volatile uint32_t *)0xe000ed08) = (uint32_t)&isr_vector;

    // SCB->CCR: enable 8-byte stack alignment for IRQ handlers, in accord with EABI
    *((volatile uint32_t *)0xe000ed14) |= 1 << 9;

    // Initialise the cpu and peripherals
    samd_init();

    // Now that we have a basic system up and running we can call main
    samd_main();

    // we must not return
    for (;;) {
    }
}

void Default_Handler(void) {
    for (;;) {
    }
}

void SysTick_Handler(void) {
    systick_ms += 1;
}

const ISR isr_vector[] __attribute__((section(".isr_vector"))) = {
    (ISR)&_estack,
    &Reset_Handler,
    &Default_Handler, // NMI_Handler
    &Default_Handler, // HardFault_Handler
    &Default_Handler, // MemManage_Handler
    &Default_Handler, // BusFault_Handler
    &Default_Handler, // UsageFault_Handler
    0,
    0,
    0,
    0,
    &Default_Handler, // SVC_Handler
    &Default_Handler, // DebugMon_Handler
    0,
    &Default_Handler, // PendSV_Handler
    &SysTick_Handler, // SysTick_Handler
    0, // line 0
    0,
    0,
    0,
    0,
    0,
    0,
    #if defined(MCU_SAMD21)
    USB_Handler_wrapper, // line 7
    #else
    0,
    #endif
    0,
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    #if defined(MCU_SAMD51)
    &USB_0_Handler_wrapper, // line 80
    &USB_1_Handler_wrapper,
    &USB_2_Handler_wrapper,
    &USB_3_Handler_wrapper,
    #else
    0,
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    #endif
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};