usbcas/USBCAS/reboot.c

#include "usbcas.h"

/* ATmega32U4 with Caterina bootloader */
#define FLASH_SIZE_BYTES	32768
#define BOOTSZ			0
#define BOOTLOADER_SEC_SIZE	(4096 >> BOOTSZ)

#define MAGIC_BOOT_KEY	0xdc42acca
#define BOOTLOADER_START_ADDRESS	(FLASH_SIZE_BYTES - BOOTLOADER_SEC_SIZE)

static uint32_t boot_key_magic ATTR_NO_INIT;

static void bootloader_jump_check(void) ATTR_INIT_SECTION(3);
static void bootloader_jump_check(void)
{
	void (* const bootloader)(void) =
		(void (*)(void))BOOTLOADER_START_ADDRESS;
	/*
	 * If the reset source was the watch dog and the boot key magic is set,
	 * clear the magic and jump into the boot loader
	 */

	if (boot_key_magic == MAGIC_BOOT_KEY) {
		boot_key_magic = 0;
		bootloader();
	}
}

/*
 * Host sent BREAK; reboot into bootloader
 */
void EVENT_CDC_Device_BreakSent(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo, const uint8_t duration)
{
	/* Set the bootloader invocation key */
	boot_key_magic = MAGIC_BOOT_KEY;

	/* Arm the watchdog to force a hardware reset */
	wdt_enable(WDTO_250MS);

	/* Return to the main loop so we ack the send break correctly */
}