| 1 | /** @file
|
|---|
| 2 | * BIOS POST routines. Used only during initialization.
|
|---|
| 3 | */
|
|---|
| 4 |
|
|---|
| 5 | /*
|
|---|
| 6 | * Copyright (C) 2004-2015 Oracle Corporation
|
|---|
| 7 | *
|
|---|
| 8 | * This file is part of VirtualBox Open Source Edition (OSE), as
|
|---|
| 9 | * available from http://www.virtualbox.org. This file is free software;
|
|---|
| 10 | * you can redistribute it and/or modify it under the terms of the GNU
|
|---|
| 11 | * General Public License (GPL) as published by the Free Software
|
|---|
| 12 | * Foundation, in version 2 as it comes in the "COPYING" file of the
|
|---|
| 13 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
|
|---|
| 14 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 15 | */
|
|---|
| 16 |
|
|---|
| 17 | #include <stdint.h>
|
|---|
| 18 | #include <string.h>
|
|---|
| 19 | #include "biosint.h"
|
|---|
| 20 | #include "inlines.h"
|
|---|
| 21 |
|
|---|
| 22 | #if DEBUG_POST
|
|---|
| 23 | # define DPRINT(...) BX_DEBUG(__VA_ARGS__)
|
|---|
| 24 | #else
|
|---|
| 25 | # define DPRINT(...)
|
|---|
| 26 | #endif
|
|---|
| 27 |
|
|---|
| 28 | /* In general, checksumming ROMs in a VM just wastes time. */
|
|---|
| 29 | //#define CHECKSUM_ROMS
|
|---|
| 30 |
|
|---|
| 31 | /* The format of a ROM is as follows:
|
|---|
| 32 | *
|
|---|
| 33 | * ------------------------------
|
|---|
| 34 | * 0 | AA55h signature (word) |
|
|---|
| 35 | * ------------------------------
|
|---|
| 36 | * 2 | Size in 512B blocks (byte) |
|
|---|
| 37 | * ------------------------------
|
|---|
| 38 | * 3 | Start of executable code |
|
|---|
| 39 | * | ....... |
|
|---|
| 40 | * end | |
|
|---|
| 41 | * ------------------------------
|
|---|
| 42 | */
|
|---|
| 43 |
|
|---|
| 44 | typedef struct rom_hdr_tag {
|
|---|
| 45 | uint16_t signature;
|
|---|
| 46 | uint8_t num_blks;
|
|---|
| 47 | uint8_t code;
|
|---|
| 48 | } rom_hdr;
|
|---|
| 49 |
|
|---|
| 50 |
|
|---|
| 51 | /* Calculate the checksum of a ROM. Note that the ROM might be
|
|---|
| 52 | * larger than 64K.
|
|---|
| 53 | */
|
|---|
| 54 | static inline uint8_t rom_checksum(uint8_t __far *rom, uint8_t blocks)
|
|---|
| 55 | {
|
|---|
| 56 | uint8_t sum = 0;
|
|---|
| 57 |
|
|---|
| 58 | #ifdef CHECKSUM_ROMS
|
|---|
| 59 | while (blocks--) {
|
|---|
| 60 | int i;
|
|---|
| 61 |
|
|---|
| 62 | for (i = 0; i < 512; ++i)
|
|---|
| 63 | sum += rom[i];
|
|---|
| 64 | /* Add 512 bytes (32 paragraphs) to segment. */
|
|---|
| 65 | rom = MK_FP(FP_SEG(rom) + (512 >> 4), 0);
|
|---|
| 66 | }
|
|---|
| 67 | #endif
|
|---|
| 68 | return sum;
|
|---|
| 69 | }
|
|---|
| 70 |
|
|---|
| 71 | /* Scan for ROMs in the given range and execute their POST code. */
|
|---|
| 72 | void rom_scan(uint16_t start_seg, uint16_t end_seg)
|
|---|
| 73 | {
|
|---|
| 74 | rom_hdr __far *rom;
|
|---|
| 75 | uint8_t rom_blks;
|
|---|
| 76 |
|
|---|
| 77 | DPRINT("Scanning for ROMs in %04X-%04X range\n", start_seg, end_seg);
|
|---|
| 78 |
|
|---|
| 79 | while (start_seg < end_seg) {
|
|---|
| 80 | rom = MK_FP(start_seg, 0);
|
|---|
| 81 | /* Check for the ROM signature. */
|
|---|
| 82 | if (rom->signature == 0xAA55) {
|
|---|
| 83 | DPRINT("Found ROM at segment %04X\n", start_seg);
|
|---|
| 84 | if (!rom_checksum((void __far *)rom, rom->num_blks)) {
|
|---|
| 85 | void (__far * rom_init)(void);
|
|---|
| 86 |
|
|---|
| 87 | /* Checksum good, initialize ROM. */
|
|---|
| 88 | rom_init = (void __far *)&rom->code;
|
|---|
| 89 | rom_init();
|
|---|
| 90 | int_disable();
|
|---|
| 91 | DPRINT("ROM initialized\n");
|
|---|
| 92 |
|
|---|
| 93 | /* Continue scanning past the end of this ROM. */
|
|---|
| 94 | rom_blks = (rom->num_blks + 3) & ~3; /* 4 blocks = 2K */
|
|---|
| 95 | start_seg += rom_blks / 4;
|
|---|
| 96 | }
|
|---|
| 97 | } else {
|
|---|
| 98 | /* Scanning is done in 2K steps. */
|
|---|
| 99 | start_seg += 2048 >> 4;
|
|---|
| 100 | }
|
|---|
| 101 | }
|
|---|
| 102 | }
|
|---|
