[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 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! */
}
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	/*
fa97bdf9	13	* Very simple screen and serial I/O
1543610a PA	14	*/
	15
	16	#include "boot.h"
	17
f4ed2877	18	int early_serial_base;
fa97bdf9 PE	19
	20	#define XMTRDY 0x20
	21
fa97bdf9	22	#define TXR 0 /* Transmit register (WRITE) */
fa97bdf9	23	#define LSR 5 /* Line Status */
fa97bdf9	24
1543610a PA	25	/*
	26	* These functions are in .inittext so they can be used to signal
	27	* error during initialization.
	28	*/
	29
fa97bdf9	30	static void __attribute__((section(".inittext"))) serial_putchar(int ch)
1543610a	31	{
fa97bdf9	32	unsigned timeout = 0xffff;
1543610a	33
fa97bdf9 PE	34	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
	35	cpu_relax();
	36
	37	outb(ch, early_serial_base + TXR);
	38	}
	39
	40	static void __attribute__((section(".inittext"))) bios_putchar(int ch)
	41	{
	42	struct biosregs ireg;
1543610a	43
df7699c5 PA	44	initregs(&ireg);
	45	ireg.bx = 0x0007;
	46	ireg.cx = 0x0001;
	47	ireg.ah = 0x0e;
	48	ireg.al = ch;
	49	intcall(0x10, &ireg, NULL);
1543610a PA	50	}
1543610a PA	51
fa97bdf9 PE	52	void __attribute__((section(".inittext"))) putchar(int ch)
	53	{
	54	if (ch == '\n')
	55	putchar('\r'); /* \n -> \r\n */
	56
	57	bios_putchar(ch);
	58
	59	if (early_serial_base != 0)
	60	serial_putchar(ch);
	61	}
	62
1543610a PA	63	void __attribute__((section(".inittext"))) puts(const char *str)
1543610a PA	64	{
df7699c5	65	while (*str)
1543610a	66	putchar(*str++);
1543610a PA	67	}
	68
	69	/*
	70	* Read the CMOS clock through the BIOS, and return the
	71	* seconds in BCD.
	72	*/
	73
	74	static u8 gettime(void)
	75	{
df7699c5	76	struct biosregs ireg, oreg;
1543610a	77
df7699c5 PA	78	initregs(&ireg);
	79	ireg.ah = 0x02;
	80	intcall(0x1a, &ireg, &oreg);
1543610a	81
df7699c5	82	return oreg.dh;
1543610a PA	83	}
	84
	85	/*
	86	* Read from the keyboard
	87	*/
	88	int getchar(void)
	89	{
df7699c5 PA	90	struct biosregs ireg, oreg;
	91
	92	initregs(&ireg);
	93	/* ireg.ah = 0x00; */
	94	intcall(0x16, &ireg, &oreg);
1543610a	95
df7699c5	96	return oreg.al;
1543610a PA	97	}
	98
	99	static int kbd_pending(void)
	100	{
df7699c5 PA	101	struct biosregs ireg, oreg;
	102
	103	initregs(&ireg);
	104	ireg.ah = 0x01;
	105	intcall(0x16, &ireg, &oreg);
	106
	107	return !(oreg.eflags & X86_EFLAGS_ZF);
1543610a PA	108	}
	109
	110	void kbd_flush(void)
	111	{
	112	for (;;) {
	113	if (!kbd_pending())
	114	break;
	115	getchar();
	116	}
	117	}
	118
	119	int getchar_timeout(void)
	120	{
	121	int cnt = 30;
	122	int t0, t1;
	123
	124	t0 = gettime();
	125
	126	while (cnt) {
	127	if (kbd_pending())
	128	return getchar();
	129
	130	t1 = gettime();
	131	if (t0 != t1) {
	132	cnt--;
	133	t0 = t1;
	134	}
	135	}
	136
	137	return 0; /* Timeout! */
	138	}
fa97bdf9	139