196 lines
7.3 KiB
C#
196 lines
7.3 KiB
C#
///////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// Microsoft Research Singularity
|
|
//
|
|
// Copyright (c) Microsoft Corporation. All rights reserved.
|
|
//
|
|
// File: Timer8254.cs
|
|
//
|
|
// Useful reference URLs:
|
|
// http://developer.intel.com/design/archives/periphrl/index.htm
|
|
// http://developer.intel.com/design/archives/periphrl/docs/7203.htm
|
|
// http://developer.intel.com/design/archives/periphrl/docs/23124406.htm
|
|
//
|
|
|
|
using Microsoft.Singularity.Io;
|
|
using Microsoft.Singularity.Configuration;
|
|
|
|
using System;
|
|
using System.Threading;
|
|
using System.Diagnostics;
|
|
|
|
namespace Microsoft.Singularity.Hal
|
|
{
|
|
[DriverCategory]
|
|
[Signature("/pnp/PNP0100")]
|
|
public sealed class Timer8254Resources : DriverCategoryDeclaration
|
|
{
|
|
[IoPortRange(0, Default = 0x0040, Length = 0x04)]
|
|
public IoPortRange port1;
|
|
|
|
[IoIrqRange(1, Default = 0x00, Length = 0x01)]
|
|
public IoIrqRange irq1;
|
|
|
|
[IoFixedPortRange(Base = 0x0061, Length = 0x01)]
|
|
public IoPortRange port2;
|
|
}
|
|
|
|
//
|
|
// Note on the i8254 timer:
|
|
//
|
|
// The clock is driven by a 14.318 MHz clock through a divide-by-12
|
|
// counter.
|
|
// This gives a clock frequency of 1.193 MHz.
|
|
// Each tick is therefore 0.838 microseconds long.
|
|
// Thus a 16 bit timer gives us a maximum delay of 0.05 seconds.
|
|
//
|
|
[CLSCompliant(false)]
|
|
public sealed class Timer8254Apic
|
|
{
|
|
// Registers
|
|
const byte i8254_C2 = 0x02; // counter 2
|
|
const byte i8254_CW = 0x03; // control word
|
|
|
|
//
|
|
//The control word to the 8254 is composed of four fields:
|
|
//bits 6-7: select the counter
|
|
//bits 4-5: select read/write
|
|
//bits 1-3: mode to use
|
|
//bit 0 : BCD mode
|
|
//
|
|
|
|
// bits 6-7 select the counter
|
|
const byte i8254_CW_SEL0 = 0x00; // select counter 0
|
|
const byte i8254_CW_SEL1 = 0x40; // select counter 1
|
|
const byte i8254_CW_SEL2 = 0x80; // select counter 2
|
|
const byte i8254_CW_RBC = 0xc0; // read-back command
|
|
|
|
// bits 4-5 select transaction type
|
|
const byte i8254_CW_CLC = 0x00; // counter latch comm.
|
|
const byte i8254_CW_LSB = 0x10; // r/w lsb only
|
|
const byte i8254_CW_MSB = 0x20; // r/w msb only
|
|
const byte i8254_CW_BOTH = 0x30; // r/w lsb, then msb
|
|
|
|
// bits 1-3 select the mode. bit 3 is sometimes a don't care
|
|
const byte i8254_CW_MODE0 = 0x00; // int. on term. count
|
|
const byte i8254_CW_MODE1 = 0x02; // h/w retrig. one-shot
|
|
const byte i8254_CW_MODE2 = 0x04; // rate generator
|
|
const byte i8254_CW_MODE3 = 0x06; // square wave mode
|
|
const byte i8254_CW_MODE4 = 0x08; // s/w trig. strobe
|
|
const byte i8254_CW_MODE5 = 0x0a; // h/w trig. strobe
|
|
|
|
// bit 0 sets BCD mode, if you really must
|
|
const byte i8254_CW_BCD = 0x01; // set BCD operation
|
|
|
|
// read-back commands use bits 4 and 5 to return status these
|
|
// are the wrong way round since the bits are inverted (RTFDS).
|
|
//
|
|
const byte i8254_RB_NOSTATUS = 0xd0; // Don't get latched count
|
|
const byte i8254_RB_NOCOUNT = 0xe0; // Don't get status
|
|
const byte i8254_RB_ALL = 0xc0; // Get status and count
|
|
|
|
// read-back commands use bits 3-1 to select counter
|
|
const byte i8254_RB_SEL2 = 0x08; // counter 2
|
|
|
|
// status from read-back is returned in bits 6-7
|
|
const byte i8254_RB_OUT = 0x80; // out pin value
|
|
const byte i8254_RB_NULL = 0x40; // 1 = count null
|
|
|
|
private static readonly int DefaultTicksPerSecond = 1193182;
|
|
private static readonly int SystemTicksPerSecond = 10000000;
|
|
|
|
private PnpConfig config;
|
|
private byte irq;
|
|
private int frequency = DefaultTicksPerSecond;
|
|
|
|
// IOPorts
|
|
private IoPort C2Port;
|
|
private IoPort CWPort;
|
|
|
|
// Constructor
|
|
internal Timer8254Apic(PnpConfig config)
|
|
{
|
|
// /pnp/08/02/01/PNP0100 0003 cfg dis : ISA 8254 Timer : AT Timer
|
|
// IRQ mask=0001 type=47
|
|
// I/O Port inf=01 min=0040 max=0040 aln=01 len=04 0040..0043
|
|
this.config = config;
|
|
this.irq = ((IoIrqRange)config.DynamicRanges[1]).Irq;
|
|
|
|
IoPortRange ioPorts = (IoPortRange) config.DynamicRanges[0];
|
|
|
|
C2Port = ioPorts.PortAtOffset(i8254_C2, 1, Access.ReadWrite);
|
|
CWPort = ioPorts.PortAtOffset(i8254_CW, 1, Access.ReadWrite);
|
|
|
|
// Use Timer2 as it's not connected as interrupt source.
|
|
//
|
|
// Lower 2 bits of port 61 are described in:
|
|
// The Indispensable PC Hardware Book (3rd Edition) p.724
|
|
ioPorts = (IoPortRange) config.FixedRanges[0];
|
|
IoPort p = ioPorts.PortAtOffset(0, 1, Access.ReadWrite);
|
|
|
|
//
|
|
// Also clear the NMI RAM parity error to enable the PCI card
|
|
// to generate NMI if the button is depressed
|
|
//
|
|
|
|
p.Write8((byte) ((p.Read8() & 0xf8) | 0x01));
|
|
}
|
|
|
|
internal void Start(ushort pitTicks)
|
|
{
|
|
CWPort.Write8(i8254_CW_MODE2 | i8254_CW_BOTH | i8254_CW_SEL2);
|
|
C2Port.Write8((byte)(pitTicks & 0xff));
|
|
C2Port.Write8((byte)(pitTicks >> 8));
|
|
do {
|
|
CWPort.Write8(i8254_RB_NOCOUNT | i8254_RB_SEL2);
|
|
} while ((C2Port.Read8() & i8254_RB_NULL) == i8254_RB_NULL);
|
|
}
|
|
|
|
internal ushort Read()
|
|
{
|
|
CWPort.Write8(i8254_RB_NOSTATUS | i8254_RB_SEL2);
|
|
return (ushort)(C2Port.Read8() | (C2Port.Read8() << 8));
|
|
}
|
|
|
|
internal void Stop()
|
|
{
|
|
CWPort.Write8(i8254_CW_MODE2 | i8254_CW_BOTH | i8254_CW_SEL2);
|
|
C2Port.Write8((byte)(0)); // LSB
|
|
// C2Port.Write8((byte)(0)); MSB DON'T!
|
|
}
|
|
|
|
internal void SetFrequency(uint newFrequency)
|
|
{
|
|
frequency = (int)newFrequency;
|
|
DebugStub.Print("i8254 frequency {0} Hz\n", __arglist(frequency));
|
|
}
|
|
|
|
internal uint TimeSpanToTimerTicks(uint ts)
|
|
{
|
|
return (uint) ((ulong)ts * (uint)(frequency / SystemTicksPerSecond));
|
|
}
|
|
|
|
internal uint TimerToTimeSpanTicks(uint ts)
|
|
{
|
|
return (uint) ((ulong)ts * (uint)(SystemTicksPerSecond / frequency));
|
|
}
|
|
|
|
#if FIXED_FREQUENCY
|
|
internal static int TimeSpanTicksToPitTicks(int ts)
|
|
{
|
|
// t = 1193182 * T / (10^7) = 0.1193182 * T
|
|
// = T * (1/0x10 + 0xe8ba/0x100000)
|
|
int tmp = (ts * 0xe8ba) >> 20;
|
|
return tmp + (ts >> 4);
|
|
}
|
|
|
|
internal static int PitTicksToTimeSpanTicks(int delta)
|
|
{
|
|
// T = 10^7 * t / 1193182 = 8.3809511 * t
|
|
// = t * (8 + 0x6186/0x10000)
|
|
return (delta << 3) + ((delta * 0x6186) >> 16);
|
|
}
|
|
#endif
|
|
}
|
|
}
|