linux_dsm_epyc7002/arch/mips/loongson/common/early_printk.c
Wu Zhangjin a3ed495190 MIPS: Loongson: Cleanup the serial port support
To share the same kernel image amon different machines we have added the
machtype command line support.

In the old serial port implementation the UART base address is hardcoded as
a macro in machine.h which breaks with machtype, so change that to discover
the address dynamically.  Also move the initialization of the UART base
address to uart_base.c to avoid remapping twice for early_printk.c and
serial.c.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/581/
Patchwork: http://patchwork.linux-mips.org/patch/682/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2009-12-17 01:57:09 +00:00

42 lines
1.0 KiB
C

/* early printk support
*
* Copyright (c) 2009 Philippe Vachon <philippe@cowpig.ca>
* Copyright (c) 2009 Lemote Inc.
* Author: Wu Zhangjin, wuzj@lemote.com
*
* 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.
*/
#include <linux/serial_reg.h>
#include <loongson.h>
#define PORT(base, offset) (u8 *)(base + offset)
static inline unsigned int serial_in(unsigned char *base, int offset)
{
return readb(PORT(base, offset));
}
static inline void serial_out(unsigned char *base, int offset, int value)
{
writeb(value, PORT(base, offset));
}
void prom_putchar(char c)
{
int timeout;
unsigned char *uart_base;
uart_base = (unsigned char *)_loongson_uart_base;
timeout = 1024;
while (((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0) &&
(timeout-- > 0))
;
serial_out(uart_base, UART_TX, c);
}