pebble/src/fw/startup/startup_stm32.c
2025-01-27 11:38:16 -08:00

73 lines
2.3 KiB
C

/*
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//! Initial firmware startup, contains the vector table that the bootloader loads.
//! Based on "https://github.com/pfalcon/cortex-uni-startup/blob/master/startup.c"
//! by Paul Sokolovsky (public domain)
#include <stdint.h>
#include <string.h>
#include <stdbool.h>
#include "mcu/cache.h"
#include "util/attributes.h"
//! These symbols are defined in the linker script for use in initializing
//! the data sections. uint8_t since we do arithmetic with section lengths.
//! These are arrays to avoid the need for an & when dealing with linker symbols.
extern uint8_t __data_load_start[];
extern uint8_t __data_start[];
extern uint8_t __data_end[];
extern uint8_t __bss_start[];
extern uint8_t __bss_end[];
extern uint8_t _estack[];
#if MICRO_FAMILY_STM32F7
extern uint8_t __dtcm_bss_start[];
extern uint8_t __dtcm_bss_end[];
#endif
//! Firmware main function, ResetHandler calls this
extern int main(void);
//! STM32 system initialization function, defined in the standard peripheral library
extern void SystemInit(void);
//! This function is what gets called when the processor first
//! starts execution following a reset event. The data and bss
//! sections are initialized, then we call the firmware's main
//! function
NORETURN Reset_Handler(void) {
// Copy data section from flash to RAM
memcpy(__data_start, __data_load_start, __data_end - __data_start);
// Clear the bss section, assumes .bss goes directly after .data
memset(__bss_start, 0, __bss_end - __bss_start);
#if MICRO_FAMILY_STM32F7
// Clear the DTCM bss section
memset(__dtcm_bss_start, 0, __dtcm_bss_end - __dtcm_bss_start);
#endif
SystemInit();
icache_enable();
dcache_enable();
main();
// Main shouldn't return
while (true) {}
}