diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:45 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 11:16:45 +0200 |
commit | 96ae6ea0be1b902c28b3b463c27da42b41e2b63a (patch) | |
tree | fbc18761d4fa93d7b0f6dbf3496289fa32bd363a /arch/x86/boot/tty.c | |
parent | 0530bf37cebcf22a73652937c2340bc1ebd92000 (diff) | |
download | linux-96ae6ea0be1b902c28b3b463c27da42b41e2b63a.tar.bz2 |
i386: move boot
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/boot/tty.c')
-rw-r--r-- | arch/x86/boot/tty.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c new file mode 100644 index 000000000000..f3f14bd26371 --- /dev/null +++ b/arch/x86/boot/tty.c @@ -0,0 +1,112 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/tty.c + * + * Very simple screen I/O + * XXX: Probably should add very simple serial I/O? + */ + +#include "boot.h" + +/* + * These functions are in .inittext so they can be used to signal + * error during initialization. + */ + +void __attribute__((section(".inittext"))) putchar(int ch) +{ + unsigned char c = ch; + + if (c == '\n') + putchar('\r'); /* \n -> \r\n */ + + /* int $0x10 is known to have bugs involving touching registers + it shouldn't. Be extra conservative... */ + asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal" + : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch)); +} + +void __attribute__((section(".inittext"))) puts(const char *str) +{ + int n = 0; + while (*str) { + putchar(*str++); + n++; + } +} + +/* + * Read the CMOS clock through the BIOS, and return the + * seconds in BCD. + */ + +static u8 gettime(void) +{ + u16 ax = 0x0200; + u16 cx, dx; + + asm volatile("int $0x1a" + : "+a" (ax), "=c" (cx), "=d" (dx) + : : "ebx", "esi", "edi"); + + return dx >> 8; +} + +/* + * Read from the keyboard + */ +int getchar(void) +{ + u16 ax = 0; + asm volatile("int $0x16" : "+a" (ax)); + + return ax & 0xff; +} + +static int kbd_pending(void) +{ + u8 pending; + asm volatile("int $0x16; setnz %0" + : "=rm" (pending) + : "a" (0x0100)); + return pending; +} + +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! */ +} |