1/*
2 * Copyright (c) 2004, 2005
3 * The Regents of The University of Michigan
4 * All Rights Reserved
5 *
6 * This code is part of the M5 simulator.
7 *
8 * Permission is granted to use, copy, create derivative works and
9 * redistribute this software and such derivative works for any
10 * purpose, so long as the copyright notice above, this grant of
11 * permission, and the disclaimer below appear in all copies made; and
12 * so long as the name of The University of Michigan is not used in
13 * any advertising or publicity pertaining to the use or distribution
14 * of this software without specific, written prior authorization.
15 *
16 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
17 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
18 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
19 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
22 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
23 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
24 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
25 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
26 * DAMAGES.
27 *
28 * Authors: Ali G. Saidi
29 * Andrew L. Schultz
30 * Miguel J. Serrano
31 */
32
33#ifndef __DEV_8254_HH__
34#define __DEV_8254_HH__
35
36#include <string>
37#include <iostream>
38
39#include "base/bitunion.hh"
40#include "sim/eventq.hh"
41#include "sim/host.hh"
42#include "sim/serialize.hh"
43
44/** Programmable Interval Timer (Intel 8254) */
45class Intel8254Timer : public EventManager
46{
47 BitUnion8(CtrlReg)
48 Bitfield<7, 6> sel;
49 Bitfield<5, 4> rw;
50 Bitfield<3, 1> mode;
51 Bitfield<0> bcd;
52 EndBitUnion(CtrlReg)
53
54 enum SelectVal {
55 SelectCounter0,
56 SelectCounter1,
57 SelectCounter2,
58 ReadBackCommand
59 };
60
61 enum ReadWriteVal {
62 LatchCommand,
63 LsbOnly,
64 MsbOnly,
65 TwoPhase
66 };
67
68 enum ModeVal {
69 InitTc,
70 OneShot,
71 RateGen,
72 SquareWave,
73 SoftwareStrobe,
74 HardwareStrobe
75 };
76
77 /** Counter element for PIT */
78 class Counter
79 {
80 /** Event for counter interrupt */
81 class CounterEvent : public Event
82 {
83 private:
84 /** Pointer back to Counter */
85 Counter* counter;
86 Tick interval;
87
88 public:
89 CounterEvent(Counter*);
90
91 /** Event process */
92 virtual void process();
93
94 /** Event description */
95 virtual const char *description() const;
96
97 friend class Counter;
98
99 void setTo(int clocks);
100 };
101
102 private:
103 std::string _name;
104 const std::string &name() const { return _name; }
105
106 CounterEvent event;
107
108 /** Current count value */
109 uint16_t count;
110
111 /** Latched count */
112 uint16_t latched_count;
113
114 /** Interrupt period */
115 uint16_t period;
116
117 /** Current mode of operation */
118 uint8_t mode;
119
120 /** Output goes high when the counter reaches zero */
121 bool output_high;
122
123 /** State of the count latch */
124 bool latch_on;
125
126 /** Set of values for read_byte and write_byte */
127 enum {LSB, MSB};
128
129 /** Determine which byte of a 16-bit count value to read/write */
130 uint8_t read_byte, write_byte;
131
132 /** Pointer to container */
133 Intel8254Timer *parent;
134
135 public:
136 Counter(Intel8254Timer *p, const std::string &name);
137
138 /** Latch the current count (if one is not already latched) */
139 void latchCount();
140
141 /** Set the read/write mode */
142 void setRW(int rw_val);
143
144 /** Set operational mode */
145 void setMode(int mode_val);
146
147 /** Set count encoding */
148 void setBCD(int bcd_val);
149
150 /** Read a count byte */
151 uint8_t read();
152
153 /** Write a count byte */
154 void write(const uint8_t data);
155
156 /** Is the output high? */
157 bool outputHigh();
158
159 /**
160 * Serialize this object to the given output stream.
161 * @param base The base name of the counter object.
162 * @param os The stream to serialize to.
163 */
164 void serialize(const std::string &base, std::ostream &os);
165
166 /**
167 * Reconstruct the state of this object from a checkpoint.
168 * @param base The base name of the counter object.
169 * @param cp The checkpoint use.
170 * @param section The section name of this object
171 */
172 void unserialize(const std::string &base, Checkpoint *cp,
173 const std::string &section);
174 };
175
176 private:
177 std::string _name;
178 const std::string &name() const { return _name; }
179
180 /** PIT has three seperate counters */
181 Counter *counter[3];
182
183 public:
184 /** Public way to access individual counters (avoid array accesses) */
185 Counter counter0;
186 Counter counter1;
187 Counter counter2;
188
189 Intel8254Timer(EventManager *em, const std::string &name);
190
191 /** Write control word */
192 void writeControl(const CtrlReg data);
193
194 /**
195 * Serialize this object to the given output stream.
196 * @param base The base name of the counter object.
197 * @param os The stream to serialize to.
198 */
199 void serialize(const std::string &base, std::ostream &os);
200
201 /**
202 * Reconstruct the state of this object from a checkpoint.
203 * @param base The base name of the counter object.
204 * @param cp The checkpoint use.
205 * @param section The section name of this object
206 */
207 void unserialize(const std::string &base, Checkpoint *cp,
208 const std::string &section);
209};
210
211#endif // __DEV_8254_HH__