69 lines
2.0 KiB
C#
69 lines
2.0 KiB
C#
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///////////////////////////////////////////////////////////////////////////////
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//
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// Microsoft Research Singularity
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// File: PmTimer.cs
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//
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// Note:
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// Power management timer
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namespace Microsoft.Singularity.Hal.Acpi
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{
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using System;
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using System.Runtime.CompilerServices;
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using Microsoft.Singularity.Io;
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[ CLSCompliant(false) ]
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public sealed class PMTimer
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{
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public const uint FrequencyHz = 3579545;
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IoPort io;
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IoMemory mem;
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int width;
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private PMTimer(uint offset, int width)
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{
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if (offset < 0xffffu) {
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this.io = new IoPort((ushort) offset, 4, Access.Read);
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}
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else {
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this.mem = IoMemory.MapPhysicalMemory(new UIntPtr(offset),
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4, true, false);
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}
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this.width = width;
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}
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/// <summary> Get the width of the timer in bits (24 or 32). </summary>
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public int Width { get { return width; } }
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/// <summary> Get the current timer value. </summary>
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public uint Value
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{
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[NoHeapAllocation]
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get {
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uint value;
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if (io != null) {
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IoResult result = io.Read32NoThrow(0, out value);
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DebugStub.Assert(IoResult.Success == result);
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}
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else {
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IoResult result = mem.Read32NoThrow(0, out value);
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DebugStub.Assert(IoResult.Success == result);
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}
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return value;
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}
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}
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public static PMTimer Create(Fadt fadt)
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{
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if ((fadt.Flags & (uint) FadtFlags.TMR_VAL_EXT) == 0) {
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return new PMTimer(fadt.PM_TMR_BLK, 24);
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}
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return new PMTimer(fadt.PM_TMR_BLK, 32);
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}
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}
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}
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