uboot-vybrid_public/board/nvidia/seaboard/seaboard.c

/*
 *  (C) Copyright 2010,2011
 *  NVIDIA Corporation <www.nvidia.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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; either version 2 of
 * the License, or (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <asm/io.h>
#include <asm/arch/tegra2.h>
#include <asm/arch/gpio.h>

/*
 * Routine: gpio_config_uart
 * Description: Force GPIO_PI3 low on Seaboard so UART4 works.
 */
void gpio_config_uart(void)
{
	int gp = GPIO_PI3;
	struct gpio_ctlr *gpio = (struct gpio_ctlr *)NV_PA_GPIO_BASE;
	struct gpio_ctlr_bank *bank = &gpio->gpio_bank[GPIO_BANK(gp)];
	u32 val;

	/* Enable UART via GPIO_PI3 (port 8, bit 3) so serial console works */
	val = readl(&bank->gpio_config[GPIO_PORT(gp)]);
	val |= 1 << GPIO_BIT(gp);
	writel(val, &bank->gpio_config[GPIO_PORT(gp)]);

	val = readl(&bank->gpio_out[GPIO_PORT(gp)]);
	val &= ~(1 << GPIO_BIT(gp));
	writel(val, &bank->gpio_out[GPIO_PORT(gp)]);

	val = readl(&bank->gpio_dir_out[GPIO_PORT(gp)]);
	val |= 1 << GPIO_BIT(gp);
	writel(val, &bank->gpio_dir_out[GPIO_PORT(gp)]);
}