VirtualBox

source: vbox/trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-pit.c@ 92580

Last change on this file since 92580 was 92524, checked in by vboxsync, 3 years ago

ValKit/bs3kit: Adding a fForcedReInit parameter to Bs3PicSetup. bugref:9044

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 5.6 KB
Line 
1/* $Id: bs3-cmn-pit.c 92524 2021-11-20 23:53:45Z vboxsync $ */
2/** @file
3 * BS3Kit - PIT Setup and Disable code.
4 */
5
6/*
7 * Copyright (C) 2007-2020 Oracle Corporation
8 *
9 * This file is part of VirtualBox Open Source Edition (OSE), as
10 * available from http://www.virtualbox.org. This file is free software;
11 * you can redistribute it and/or modify it under the terms of the GNU
12 * General Public License (GPL) as published by the Free Software
13 * Foundation, in version 2 as it comes in the "COPYING" file of the
14 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16 *
17 * The contents of this file may alternatively be used under the terms
18 * of the Common Development and Distribution License Version 1.0
19 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20 * VirtualBox OSE distribution, in which case the provisions of the
21 * CDDL are applicable instead of those of the GPL.
22 *
23 * You may elect to license modified versions of this file under the
24 * terms and conditions of either the GPL or the CDDL or both.
25 */
26
27
28/*********************************************************************************************************************************
29* Header Files *
30*********************************************************************************************************************************/
31#include "bs3kit-template-header.h"
32#include <iprt/asm-amd64-x86.h>
33
34
35/*********************************************************************************************************************************
36* Defined Constants And Macros *
37*********************************************************************************************************************************/
38#define BS3_PIT_PORT_CMD 0x43
39#define BS3_PIT_PORT_CH0_DATA 0x40
40#define BS3_PIT_HZ UINT32_C(1193182)
41
42
43/*********************************************************************************************************************************
44* External Symbols *
45*********************************************************************************************************************************/
46extern FNBS3TRAPHANDLER16 bs3PitIrqHandler_c16;
47extern FNBS3TRAPHANDLER32 bs3PitIrqHandler_c32;
48extern FNBS3TRAPHANDLER64 bs3PitIrqHandler_c64;
49
50
51#undef Bs3PitSetupAndEnablePeriodTimer
52BS3_CMN_DEF(void, Bs3PitSetupAndEnablePeriodTimer,(uint16_t cHzDesired))
53{
54 RTCCUINTREG fSaved;
55 uint16_t cCount;
56 uint16_t cMsInterval;
57 uint32_t cNsInterval;
58
59 /*
60 * Disable the PIT and make sure we've configured the IRQ handlers.
61 */
62 Bs3PitDisable();
63 Bs3PicSetup(false /*fForcedReInit*/);
64 Bs3TrapSetHandlerEx(0x70, bs3PitIrqHandler_c16, bs3PitIrqHandler_c32, bs3PitIrqHandler_c64);
65
66 /*
67 * Reset the counters.
68 */
69 g_cBs3PitNs = 0;
70 g_cBs3PitMs = 0;
71 g_cBs3PitTicks = 0;
72
73 /*
74 * Calculate an interval.
75 */
76 if (cHzDesired <= 18)
77 {
78 cCount = 0; /* 1193182 / 65536 = 18.206512451171875 Hz */
79 cHzDesired = 18;
80 cNsInterval = UINT32_C(54925401); /* 65536 / 1193182 = 0.054925401154224586022920225078823 seconds */
81 cMsInterval = 55;
82 }
83 else
84 {
85 cCount = BS3_PIT_HZ / cHzDesired;
86 cHzDesired = BS3_PIT_HZ / cCount;
87 /* 1s/1193182 = 0.000 000 838 095 110 38550698887512550474278 */
88#if ARCH_BITS == 64
89 cNsInterval = cCount * UINT64_C(838095110) / 1000000;
90#elif ARCH_BITS == 32
91 cNsInterval = cCount * UINT32_C(8381) / 10;
92#else
93 cNsInterval = cCount * 838;
94#endif
95 if (cCount <= 1194)
96 cMsInterval = 1; /* Must not be zero! */
97 else
98 cMsInterval = cCount / 1194;
99 }
100
101
102 /*
103 * Do the reprogramming.
104 */
105 fSaved = ASMIntDisableFlags();
106 ASMOutU8(BS3_PIT_PORT_CMD,
107 (0 << 6) /* select: channel 0 */
108 | (3 << 4) /* access mode: lobyte/hibyte */
109 | (2 << 1) /* operation: Mode 2 */
110 | 0 /* binary mode */
111 );
112 ASMOutU8(BS3_PIT_PORT_CH0_DATA, (uint8_t)cCount);
113 ASMOutU8(BS3_PIT_PORT_CH0_DATA, (uint8_t)(cCount >> 8));
114
115 g_cBs3PitIntervalNs = cNsInterval;
116 g_cBs3PitIntervalHz = cHzDesired;
117 g_cBs3PitIntervalMs = cMsInterval;
118
119 Bs3PicUpdateMask(UINT16_C(0xfffe), 0);
120
121 ASMSetFlags(fSaved);
122}
123
124
125#undef Bs3PitDisable
126BS3_CMN_DEF(void, Bs3PitDisable,(void))
127{
128 if (g_cBs3PitIntervalHz != 0)
129 {
130 RTCCUINTREG fSaved = ASMIntDisableFlags();
131
132 /*
133 * Not entirely sure what's the best way to do this, but let's try reprogram
134 * it to a no-reload mode like 0 and set the count to 1.
135 */
136 g_cBs3PitIntervalMs = 0;
137 ASMOutU8(BS3_PIT_PORT_CMD,
138 (0 << 6) /* select: channel 0 */
139 | (1 << 4) /* access mode: lobyte */
140 | (0 << 1) /* operation: Mode 0 */
141 | 0 /* binary mode */
142 );
143 ASMOutU8(BS3_PIT_PORT_CH0_DATA, (uint8_t)1);
144
145 /*
146 * Then mask the PIT IRQ on the PIC.
147 */
148 Bs3PicUpdateMask(UINT16_C(0xffff), 1);
149
150 ASMSetFlags(fSaved);
151 }
152
153 /*
154 * Reset the interval values (leave the ticks and elapsed ns/ms values as-is).
155 */
156 g_cBs3PitIntervalNs = 0;
157 g_cBs3PitIntervalMs = 0;
158 g_cBs3PitIntervalHz = 0;
159}
160
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