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/*
* 8250/16550-type serial ports prom_putchar()
*
* Copyright (C) 2010 Yoichi Yuasa <yuasa@linux-mips.org>
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/io.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
static void __iomem *serial8250_base;
static unsigned int serial8250_reg_shift;
static unsigned int serial8250_tx_timeout;
void setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift,
unsigned int timeout)
{
serial8250_base = (void __iomem *)base;
serial8250_reg_shift = reg_shift;
serial8250_tx_timeout = timeout;
}
static inline u8 serial_in(int offset)
{
return readb(serial8250_base + (offset << serial8250_reg_shift));
}
static inline void serial_out(int offset, char value)
{
writeb(value, serial8250_base + (offset << serial8250_reg_shift));
}
void prom_putchar(char c)
{
unsigned int timeout;
int status, bits;
if (!serial8250_base)
return;
timeout = serial8250_tx_timeout;
bits = UART_LSR_TEMT | UART_LSR_THRE;
do {
status = serial_in(UART_LSR);
if (--timeout == 0)
break;
} while ((status & bits) != bits);
if (timeout)
serial_out(UART_TX, c);
}
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