mh
/
qmk_firmware
mirror of https://github.com/qmk/qmk_firmware/


								// Copyright 2023 Nick Brassel (@tzarc)

								// SPDX-License-Identifier: GPL-2.0-or-later

								#include <hal.h>

								#define BOOTLOADER_MAGIC 0xDEADBEEF


								////////////////////////////////////////////////////////////////////////////////

								// Different signalling for bootloader entry

								// - RAM is cleared on reset, so we can't use the usual __ram0_end__ symbol.

								// - Use backup registers in the RTC peripheral to store the magic value instead.


								static inline void enable_backup_register_access(void) {

								    PWR->CR1 |= PWR_CR1_DBP;

								}


								static inline void disable_backup_register_access(void) {

								    PWR->CR1 &= ~PWR_CR1_DBP;

								}


								void bootloader_marker_enable(void) {

								    enable_backup_register_access();

								    RTC->BKP0R = BOOTLOADER_MAGIC;

								    disable_backup_register_access();

								}


								bool bootloader_marker_active(void) {

								    enable_backup_register_access();

								    bool ret = RTC->BKP0R == BOOTLOADER_MAGIC;

								    disable_backup_register_access();

								    return ret;

								}


								void bootloader_marker_disable(void) {

								    enable_backup_register_access();

								    RTC->BKP0R = 0;

								    disable_backup_register_access();

								}