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/*
* Copyright (c) 2004, 2005
* The Regents of The University of Michigan
* All Rights Reserved
*
* This code is part of the M5 simulator.
*
* Permission is granted to use, copy, create derivative works and
* redistribute this software and such derivative works for any
* purpose, so long as the copyright notice above, this grant of
* permission, and the disclaimer below appear in all copies made; and
* so long as the name of The University of Michigan is not used in
* any advertising or publicity pertaining to the use or distribution
* of this software without specific, written prior authorization.
*
* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
* UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
* WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
* LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
* INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
* ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGES.
*
* Authors: Ali G. Saidi
* Andrew L. Schultz
* Miguel J. Serrano
*/
#ifndef __DEV_8254_HH__
#define __DEV_8254_HH__
#include <string>
#include <iostream>
#include "base/bitunion.hh"
#include "sim/eventq.hh"
#include "sim/host.hh"
#include "sim/serialize.hh"
/** Programmable Interval Timer (Intel 8254) */
class Intel8254Timer : public EventManager
{
BitUnion8(CtrlReg)
Bitfield<7, 6> sel;
Bitfield<5, 4> rw;
Bitfield<3, 1> mode;
Bitfield<0> bcd;
EndBitUnion(CtrlReg)
enum SelectVal {
SelectCounter0,
SelectCounter1,
SelectCounter2,
ReadBackCommand
};
enum ReadWriteVal {
LatchCommand,
LsbOnly,
MsbOnly,
TwoPhase
};
enum ModeVal {
InitTc,
OneShot,
RateGen,
SquareWave,
SoftwareStrobe,
HardwareStrobe
};
/** Counter element for PIT */
class Counter
{
/** Event for counter interrupt */
class CounterEvent : public Event
{
private:
/** Pointer back to Counter */
Counter* counter;
Tick interval;
public:
CounterEvent(Counter*);
/** Event process */
virtual void process();
/** Event description */
virtual const char *description() const;
friend class Counter;
void setTo(int clocks);
};
private:
std::string _name;
const std::string &name() const { return _name; }
CounterEvent event;
/** Current count value */
uint16_t count;
/** Latched count */
uint16_t latched_count;
/** Interrupt period */
uint16_t period;
/** Current mode of operation */
uint8_t mode;
/** Output goes high when the counter reaches zero */
bool output_high;
/** State of the count latch */
bool latch_on;
/** Set of values for read_byte and write_byte */
enum {LSB, MSB};
/** Determine which byte of a 16-bit count value to read/write */
uint8_t read_byte, write_byte;
/** Pointer to container */
Intel8254Timer *parent;
public:
Counter(Intel8254Timer *p, const std::string &name);
/** Latch the current count (if one is not already latched) */
void latchCount();
/** Set the read/write mode */
void setRW(int rw_val);
/** Set operational mode */
void setMode(int mode_val);
/** Set count encoding */
void setBCD(int bcd_val);
/** Read a count byte */
uint8_t read();
/** Write a count byte */
void write(const uint8_t data);
/** Is the output high? */
bool outputHigh();
/**
* Serialize this object to the given output stream.
* @param base The base name of the counter object.
* @param os The stream to serialize to.
*/
void serialize(const std::string &base, std::ostream &os);
/**
* Reconstruct the state of this object from a checkpoint.
* @param base The base name of the counter object.
* @param cp The checkpoint use.
* @param section The section name of this object
*/
void unserialize(const std::string &base, Checkpoint *cp,
const std::string §ion);
};
private:
std::string _name;
const std::string &name() const { return _name; }
/** PIT has three seperate counters */
Counter *counter[3];
public:
/** Public way to access individual counters (avoid array accesses) */
Counter counter0;
Counter counter1;
Counter counter2;
Intel8254Timer(EventManager *em, const std::string &name);
/** Write control word */
void writeControl(const CtrlReg data);
/**
* Serialize this object to the given output stream.
* @param base The base name of the counter object.
* @param os The stream to serialize to.
*/
void serialize(const std::string &base, std::ostream &os);
/**
* Reconstruct the state of this object from a checkpoint.
* @param base The base name of the counter object.
* @param cp The checkpoint use.
* @param section The section name of this object
*/
void unserialize(const std::string &base, Checkpoint *cp,
const std::string §ion);
};
#endif // __DEV_8254_HH__
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