[deliverable/linux.git] / arch / x86 / boot / tty.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 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)
{
	struct biosregs ireg;

	if (ch == '\n')
		putchar('\r');	/* \n -> \r\n */

	initregs(&ireg);
	ireg.bx = 0x0007;
	ireg.cx = 0x0001;
	ireg.ah = 0x0e;
	ireg.al = ch;
	intcall(0x10, &ireg, NULL);
}

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! */
}
Commit	Line	Data
1543610a PA	1	/* -- linux-c -- ------------------------------------------------------- *
	2	*
	3	* Copyright (C) 1991, 1992 Linus Torvalds
	4	* Copyright 2007 rPath, Inc. - All Rights Reserved
df7699c5	5	* Copyright 2009 Intel Corporation; author H. Peter Anvin
1543610a PA	6	*
	7	* This file is part of the Linux kernel, and is made available under
	8	* the terms of the GNU General Public License version 2.
	9	*
	10	* ----------------------------------------------------------------------- */
	11
	12	/*
1543610a PA	13	* Very simple screen I/O
	14	* XXX: Probably should add very simple serial I/O?
	15	*/
	16
	17	#include "boot.h"
	18
	19	/*
	20	* These functions are in .inittext so they can be used to signal
	21	* error during initialization.
	22	*/
	23
	24	void __attribute__((section(".inittext"))) putchar(int ch)
	25	{
df7699c5	26	struct biosregs ireg;
1543610a	27
df7699c5	28	if (ch == '\n')
1543610a PA	29	putchar('\r'); /* \n -> \r\n */
1543610a PA	30
df7699c5 PA	31	initregs(&ireg);
	32	ireg.bx = 0x0007;
	33	ireg.cx = 0x0001;
	34	ireg.ah = 0x0e;
	35	ireg.al = ch;
	36	intcall(0x10, &ireg, NULL);
1543610a PA	37	}
	38
	39	void __attribute__((section(".inittext"))) puts(const char *str)
	40	{
df7699c5	41	while (*str)
1543610a	42	putchar(*str++);
1543610a PA	43	}
	44
	45	/*
	46	* Read the CMOS clock through the BIOS, and return the
	47	* seconds in BCD.
	48	*/
	49
	50	static u8 gettime(void)
	51	{
df7699c5	52	struct biosregs ireg, oreg;
1543610a	53
df7699c5 PA	54	initregs(&ireg);
	55	ireg.ah = 0x02;
	56	intcall(0x1a, &ireg, &oreg);
1543610a	57
df7699c5	58	return oreg.dh;
1543610a PA	59	}
	60
	61	/*
	62	* Read from the keyboard
	63	*/
	64	int getchar(void)
	65	{
df7699c5 PA	66	struct biosregs ireg, oreg;
	67
	68	initregs(&ireg);
	69	/* ireg.ah = 0x00; */
	70	intcall(0x16, &ireg, &oreg);
1543610a	71
df7699c5	72	return oreg.al;
1543610a PA	73	}
	74
	75	static int kbd_pending(void)
	76	{
df7699c5 PA	77	struct biosregs ireg, oreg;
	78
	79	initregs(&ireg);
	80	ireg.ah = 0x01;
	81	intcall(0x16, &ireg, &oreg);
	82
	83	return !(oreg.eflags & X86_EFLAGS_ZF);
1543610a PA	84	}
	85
	86	void kbd_flush(void)
	87	{
	88	for (;;) {
	89	if (!kbd_pending())
	90	break;
	91	getchar();
	92	}
	93	}
	94
	95	int getchar_timeout(void)
	96	{
	97	int cnt = 30;
	98	int t0, t1;
	99
	100	t0 = gettime();
	101
	102	while (cnt) {
	103	if (kbd_pending())
	104	return getchar();
	105
	106	t1 = gettime();
	107	if (t0 != t1) {
	108	cnt--;
	109	t0 = t1;
	110	}
	111	}
	112
	113	return 0; /* Timeout! */
	114	}