keychron_qmk_firmware/common/bootloader.c

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "bootloader.h"

/* Start Bootloader from Application
 * See 
 * http://www.pjrc.com/teensy/jump_to_bootloader.html
 * http://www.fourwalledcubicle.com/files/LUFA/Doc/120219/html/_page__software_bootloader_start.html
 */

// TODO: support usbasp
/* Boot Section Size in bytes
 * Teensy halfKay   512
 * Atmel DFU loader 4096
 * LUFA bootloader  4096
 */
#ifndef BOOT_SIZE
#define BOOT_SIZE 512
#endif

#define FLASH_SIZE          (FLASHEND + 1)
#define BOOTLOADER_START    (FLASHEND - BOOT_SIZE)

void bootloader_jump(void) {
    cli();

    //
    //Teensy
    //
#if defined(__AVR_AT90USB162__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
    // disable watchdog, if enabled
    // disable all peripherals
    UDCON = 1;
    USBCON = (1<<FRZCLK);  // disable USB
    UCSR1B = 0;
    _delay_ms(5);
#else
    // This makes custom USBasploader come up.
    MCUSR = 0;
#endif

#if defined(__AVR_AT90USB162__)
    EIMSK = 0; PCICR = 0; SPCR = 0; ACSR = 0; EECR = 0;
    TIMSK0 = 0; TIMSK1 = 0; UCSR1B = 0;
    DDRB = 0; DDRC = 0; DDRD = 0;
    PORTB = 0; PORTC = 0; PORTD = 0;
#elif defined(__AVR_ATmega32U4__)
    EIMSK = 0; PCICR = 0; SPCR = 0; ACSR = 0; EECR = 0; ADCSRA = 0;
    TIMSK0 = 0; TIMSK1 = 0; TIMSK3 = 0; TIMSK4 = 0; UCSR1B = 0; TWCR = 0;
    DDRB = 0; DDRC = 0; DDRD = 0; DDRE = 0; DDRF = 0; TWCR = 0;
    PORTB = 0; PORTC = 0; PORTD = 0; PORTE = 0; PORTF = 0;
#elif defined(__AVR_AT90USB646__)
    EIMSK = 0; PCICR = 0; SPCR = 0; ACSR = 0; EECR = 0; ADCSRA = 0;
    TIMSK0 = 0; TIMSK1 = 0; TIMSK2 = 0; TIMSK3 = 0; UCSR1B = 0; TWCR = 0;
    DDRA = 0; DDRB = 0; DDRC = 0; DDRD = 0; DDRE = 0; DDRF = 0;
    PORTA = 0; PORTB = 0; PORTC = 0; PORTD = 0; PORTE = 0; PORTF = 0;
#elif defined(__AVR_AT90USB1286__)
    EIMSK = 0; PCICR = 0; SPCR = 0; ACSR = 0; EECR = 0; ADCSRA = 0;
    TIMSK0 = 0; TIMSK1 = 0; TIMSK2 = 0; TIMSK3 = 0; UCSR1B = 0; TWCR = 0;
    DDRA = 0; DDRB = 0; DDRC = 0; DDRD = 0; DDRE = 0; DDRF = 0;
    PORTA = 0; PORTB = 0; PORTC = 0; PORTD = 0; PORTE = 0; PORTF = 0;
#endif


    //
    //USBasp
    //
#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega328P__)
    // This makes custom USBasploader come up.
    MCUSR = 0;

    // initialize ports
    PORTB = 0; PORTC= 0; PORTD = 0;
    DDRB = 0; DDRC= 0; DDRD = 0;

    // disable interrupts
    EIMSK = 0; EECR = 0; SPCR = 0;
    ACSR = 0; SPMCSR = 0; WDTCSR = 0; PCICR = 0;
    TIMSK0 = 0; TIMSK1 = 0; TIMSK2 = 0;
    ADCSRA = 0; TWCR = 0; UCSR0B = 0;
#endif


    // start Bootloader
    ((void (*)(void))BOOTLOADER_START)();
}