bootsel-reboot.cpp

#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/gpio.h"
#include "hardware/sync.h"
#include "hardware/structs/ioqspi.h"
#include "hardware/structs/sio.h"

extern "C" {
	#include "hardware/watchdog.h"
}

#include "bootsel-reboot.hpp"

bool __no_inline_not_in_flash_func(get_bootsel_button)() {
	const uint CS_PIN_INDEX = 1;

	// Must disable interrupts, as interrupt handlers may be in flash, and we
	// are about to temporarily disable flash access!
	uint32_t flags = save_and_disable_interrupts();

	// Set chip select to Hi-Z
	hw_write_masked(&ioqspi_hw->io[CS_PIN_INDEX].ctrl,
		GPIO_OVERRIDE_LOW << IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_LSB,
		IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_BITS);

	// Note we can't call into any sleep functions in flash right now
	for (volatile int i = 0; i < 1000; ++i);

	// The HI GPIO registers in SIO can observe and control the 6 QSPI pins.
	// Note the button pulls the pin *low* when pressed.
	bool button_state = !(sio_hw->gpio_hi_in & (1u << CS_PIN_INDEX));

	// Need to restore the state of chip select, else we are going to have a
	// bad time when we return to code in flash!
	hw_write_masked(&ioqspi_hw->io[CS_PIN_INDEX].ctrl,
		GPIO_OVERRIDE_NORMAL << IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_LSB,
		IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_BITS);

	restore_interrupts(flags);

	return button_state;
}

void arm_watchdog() {
	watchdog_enable(WATCHDOG_TIMEOUT, 1);
}

void update_watchdog() {
	watchdog_update();
}

void check_bootsel_button() {
	if (get_bootsel_button() == 1) {
		puts("Rebooting...\n");
		while(1);
	}
	update_watchdog();
}