nes-proj/cpu/avr/bootloader.c

106 lines
2.1 KiB
C
Raw Normal View History

#include "bootloader.h"
#include "dev/watchdog.h"
#include <util/delay.h>
#include <avr/wdt.h>
2010-11-03 16:55:40 +00:00
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "dev/usb/usb_drv.h"
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <avr/eeprom.h>
/* MCUSR is a deprecated name but older avr-libc versions may define it */
#if !defined (MCUCSR)
# if defined (MCUSR)
# warning *** MCUCSR not defined, using MCUSR instead ***
# define MCUCSR MCUSR
# endif
#endif
#ifndef EEPROM_MAGIC_BYTE_ADDR
#define EEPROM_MAGIC_BYTE_ADDR (uint8_t*)(E2END-3)
#endif
volatile uint32_t Boot_Key ATTR_NO_INIT;
extern void Bootloader_Jump_Check(void) ATTR_INIT_SECTION(3);
bool
bootloader_is_present(void)
{
#if defined(BOOTLOADER_START_ADDRESS)
return pgm_read_word_far(BOOTLOADER_START_ADDRESS) != 0xFFFF;
#else
return false;
#endif
}
void
Jump_To_Bootloader(void)
{
/* Disable all interrupts */
cli();
#ifdef UDCON
/* If USB is used, detach from the bus */
Usb_detach();
uint8_t i;
/* Wait two seconds for the USB detachment to register on the host */
for(i = 0; i < 200; i++) {
_delay_ms(10);
watchdog_periodic();
}
#endif
/* Set the bootloader key to the magic value and force a reset */
Boot_Key = MAGIC_BOOT_KEY;
eeprom_write_byte(EEPROM_MAGIC_BYTE_ADDR, 0xFF);
/* Enable interrupts */
sei();
watchdog_reboot();
}
void
Bootloader_Jump_Check(void)
{
/* If the reset source was the bootloader and the key is correct,
* clear it and jump to the bootloader
*/
if(MCUCSR & (1 << WDRF)) {
MCUCSR = 0;
if(Boot_Key == MAGIC_BOOT_KEY) {
Boot_Key = 0;
wdt_disable();
/* Disable all interrupts */
cli();
eeprom_write_byte(EEPROM_MAGIC_BYTE_ADDR, 0xFF);
/* Enable interrupts */
sei();
((void (*)(void))(BOOTLOADER_START_ADDRESS)) ();
} else {
/* The watchdog fired. Probably means we
* crashed. Wait two seconds before continuing.
*/
Boot_Key++;
uint8_t i;
for(i = 0; i < 200; i++) {
_delay_ms(10);
watchdog_periodic();
}
}
} else {
Boot_Key = MAGIC_BOOT_KEY - 4;
}
}