forked from Minki/linux
f4ed2877b1
Separate early_serial_console from tty.c
This allows for reuse of
early_serial_console.c/string.c/printf.c/cmdline.c in boot/compressed/.
-v2: according to hpa, don't include string.c etc
-v3: compressed/misc.c must have early_serial_base as static, so move it back to tty.c
for setup code
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C568D2B.205@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
140 lines
2.4 KiB
C
140 lines
2.4 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright 2007 rPath, Inc. - All Rights Reserved
|
|
* Copyright 2009 Intel Corporation; author H. Peter Anvin
|
|
*
|
|
* This file is part of the Linux kernel, and is made available under
|
|
* the terms of the GNU General Public License version 2.
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* Very simple screen and serial I/O
|
|
*/
|
|
|
|
#include "boot.h"
|
|
|
|
int early_serial_base;
|
|
|
|
#define XMTRDY 0x20
|
|
|
|
#define TXR 0 /* Transmit register (WRITE) */
|
|
#define LSR 5 /* Line Status */
|
|
|
|
/*
|
|
* These functions are in .inittext so they can be used to signal
|
|
* error during initialization.
|
|
*/
|
|
|
|
static void __attribute__((section(".inittext"))) serial_putchar(int ch)
|
|
{
|
|
unsigned timeout = 0xffff;
|
|
|
|
while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
|
|
cpu_relax();
|
|
|
|
outb(ch, early_serial_base + TXR);
|
|
}
|
|
|
|
static void __attribute__((section(".inittext"))) bios_putchar(int ch)
|
|
{
|
|
struct biosregs ireg;
|
|
|
|
initregs(&ireg);
|
|
ireg.bx = 0x0007;
|
|
ireg.cx = 0x0001;
|
|
ireg.ah = 0x0e;
|
|
ireg.al = ch;
|
|
intcall(0x10, &ireg, NULL);
|
|
}
|
|
|
|
void __attribute__((section(".inittext"))) putchar(int ch)
|
|
{
|
|
if (ch == '\n')
|
|
putchar('\r'); /* \n -> \r\n */
|
|
|
|
bios_putchar(ch);
|
|
|
|
if (early_serial_base != 0)
|
|
serial_putchar(ch);
|
|
}
|
|
|
|
void __attribute__((section(".inittext"))) puts(const char *str)
|
|
{
|
|
while (*str)
|
|
putchar(*str++);
|
|
}
|
|
|
|
/*
|
|
* Read the CMOS clock through the BIOS, and return the
|
|
* seconds in BCD.
|
|
*/
|
|
|
|
static u8 gettime(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ah = 0x02;
|
|
intcall(0x1a, &ireg, &oreg);
|
|
|
|
return oreg.dh;
|
|
}
|
|
|
|
/*
|
|
* Read from the keyboard
|
|
*/
|
|
int getchar(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
/* ireg.ah = 0x00; */
|
|
intcall(0x16, &ireg, &oreg);
|
|
|
|
return oreg.al;
|
|
}
|
|
|
|
static int kbd_pending(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ah = 0x01;
|
|
intcall(0x16, &ireg, &oreg);
|
|
|
|
return !(oreg.eflags & X86_EFLAGS_ZF);
|
|
}
|
|
|
|
void kbd_flush(void)
|
|
{
|
|
for (;;) {
|
|
if (!kbd_pending())
|
|
break;
|
|
getchar();
|
|
}
|
|
}
|
|
|
|
int getchar_timeout(void)
|
|
{
|
|
int cnt = 30;
|
|
int t0, t1;
|
|
|
|
t0 = gettime();
|
|
|
|
while (cnt) {
|
|
if (kbd_pending())
|
|
return getchar();
|
|
|
|
t1 = gettime();
|
|
if (t0 != t1) {
|
|
cnt--;
|
|
t0 = t1;
|
|
}
|
|
}
|
|
|
|
return 0; /* Timeout! */
|
|
}
|
|
|