u-boot/drivers/serial/altera_uart.c

/*
 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
 * Scott McNutt <smcnutt@psyent.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 <watchdog.h>
#include <asm/io.h>
#include <nios2-io.h>
#include <linux/compiler.h>
#include <serial.h>

DECLARE_GLOBAL_DATA_PTR;

/*------------------------------------------------------------------
 * UART the serial port
 *-----------------------------------------------------------------*/

static nios_uart_t *uart = (nios_uart_t *) CONFIG_SYS_NIOS_CONSOLE;

#if defined(CONFIG_SYS_NIOS_FIXEDBAUD)

/*
 * Everything's already setup for fixed-baud PTF
 * assignment
 */
static void altera_serial_setbrg(void)
{
}

static int altera_serial_init(void)
{
	return 0;
}

#else

static void altera_serial_setbrg(void)
{
	unsigned div;

	div = (CONFIG_SYS_CLK_FREQ/gd->baudrate)-1;
	writel (div, &uart->divisor);
}

static int altera_serial_init(void)
{
	serial_setbrg();
	return 0;
}

#endif /* CONFIG_SYS_NIOS_FIXEDBAUD */

/*-----------------------------------------------------------------------
 * UART CONSOLE
 *---------------------------------------------------------------------*/
static void altera_serial_putc(char c)
{
	if (c == '\n')
		serial_putc ('\r');
	while ((readl (&uart->status) & NIOS_UART_TRDY) == 0)
		WATCHDOG_RESET ();
	writel ((unsigned char)c, &uart->txdata);
}

static void altera_serial_puts(const char *s)
{
	while (*s != 0) {
		serial_putc (*s++);
	}
}

static int altera_serial_tstc(void)
{
	return (readl (&uart->status) & NIOS_UART_RRDY);
}

static int altera_serial_getc(void)
{
	while (serial_tstc () == 0)
		WATCHDOG_RESET ();
	return (readl (&uart->rxdata) & 0x00ff );
}

static struct serial_device altera_serial_drv = {
	.name	= "altera_serial",
	.start	= altera_serial_init,
	.stop	= NULL,
	.setbrg	= altera_serial_setbrg,
	.putc	= altera_serial_putc,
	.puts	= altera_serial_puts,
	.getc	= altera_serial_getc,
	.tstc	= altera_serial_tstc,
};

void altera_serial_initialize(void)
{
	serial_register(&altera_serial_drv);
}

__weak struct serial_device *default_serial_console(void)
{
	return &altera_serial_drv;
}