qmk_firmware/platforms/avr/bootloaders/usbasploader.c

66 lines
2.4 KiB
C

/* Copyright 2021 QMK
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "bootloader.h"
#include <avr/wdt.h>
#define FLASH_SIZE (FLASHEND + 1L)
#if !defined(MCUCSR)
# if defined(MCUSR)
# define MCUCSR MCUSR
# endif
#endif
__attribute__((weak)) void bootloader_jump(void) {
// Taken with permission of Stephan Baerwolf from https://github.com/tinyusbboard/API/blob/master/apipage.c
wdt_enable(WDTO_15MS);
wdt_reset();
asm volatile("cli \n\t"
"ldi r29 , %[ramendhi] \n\t"
"ldi r28 , %[ramendlo] \n\t"
#if (FLASHEND > 131071)
"ldi r18 , %[bootaddrhi] \n\t"
"st Y+, r18 \n\t"
#endif
"ldi r18 , %[bootaddrme] \n\t"
"st Y+, r18 \n\t"
"ldi r18 , %[bootaddrlo] \n\t"
"st Y+, r18 \n\t"
"out %[mcucsrio], __zero_reg__ \n\t"
"bootloader_startup_loop%=: \n\t"
"rjmp bootloader_startup_loop%= \n\t"
:
: [mcucsrio] "I"(_SFR_IO_ADDR(MCUCSR)),
#if (FLASHEND > 131071)
[ramendhi] "M"(((RAMEND - 2) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 2) >> 0) & 0xff), [bootaddrhi] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
#else
[ramendhi] "M"(((RAMEND - 1) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 1) >> 0) & 0xff),
#endif
[bootaddrme] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [bootaddrlo] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
}
__attribute__((weak)) void mcu_reset(void) {
// setup watchdog timeout
wdt_enable(WDTO_15MS);
// wait for watchdog timer to trigger
while (1) {
}
}