src/mainboard/google/nyan_blaze/boardid.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright 2014 Google Inc.
 *
 * 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; version 2 of the License.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <console/console.h>
#include <soc/nvidia/tegra124/gpio.h>
#include <stdlib.h>

#include <boardid.h>

uint8_t board_id(void)
{
	static int id = -1;

	if (id < 0) {
		gpio_t gpio[] = {GPIO(Q3), GPIO(T1), GPIO(X1), GPIO(X4)};
		int value[ARRAY_SIZE(gpio)];

		gpio_get_in_tristate_values(gpio, ARRAY_SIZE(gpio), value);

		/* A gpio state is encoded in every two-bit */
		id = value[0] << 0 |
		     value[1] << 2 |
		     value[2] << 4 |
		     value[3] << 6;
		printk(BIOS_SPEW, "Board TRISTATE ID: %#x.\n", id);
	}

	return id;
}