H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 1 | /* -*- linux-c -*- ------------------------------------------------------- * |
| 2 | * |
| 3 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 4 | * Copyright 2007 rPath, Inc. - All Rights Reserved |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 5 | * Copyright 2009 Intel Corporation; author H. Peter Anvin |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 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 | /* |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 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 | { |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 26 | struct biosregs ireg; |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 27 | |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 28 | if (ch == '\n') |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 29 | putchar('\r'); /* \n -> \r\n */ |
| 30 | |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 31 | initregs(&ireg); |
| 32 | ireg.bx = 0x0007; |
| 33 | ireg.cx = 0x0001; |
| 34 | ireg.ah = 0x0e; |
| 35 | ireg.al = ch; |
| 36 | intcall(0x10, &ireg, NULL); |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 37 | } |
| 38 | |
| 39 | void __attribute__((section(".inittext"))) puts(const char *str) |
| 40 | { |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 41 | while (*str) |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 42 | putchar(*str++); |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 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 | { |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 52 | struct biosregs ireg, oreg; |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 53 | |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 54 | initregs(&ireg); |
| 55 | ireg.ah = 0x02; |
| 56 | intcall(0x1a, &ireg, &oreg); |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 57 | |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 58 | return oreg.dh; |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | /* |
| 62 | * Read from the keyboard |
| 63 | */ |
| 64 | int getchar(void) |
| 65 | { |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 66 | struct biosregs ireg, oreg; |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 67 | |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 68 | initregs(&ireg); |
| 69 | /* ireg.ah = 0x00; */ |
| 70 | intcall(0x16, &ireg, &oreg); |
| 71 | |
| 72 | return oreg.al; |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 73 | } |
| 74 | |
| 75 | static int kbd_pending(void) |
| 76 | { |
H. Peter Anvin | df7699c | 2009-04-01 18:13:46 -0700 | [diff] [blame^] | 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); |
H. Peter Anvin | 1543610 | 2007-07-11 12:18:45 -0700 | [diff] [blame] | 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 | } |