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#include "base/misc.hh"
34#include "dev/intel_8254_timer.hh"
35
36using namespace std;
37
38Intel8254Timer::Intel8254Timer(EventManager *em, const string &name)
39 : EventManager(em), _name(name),
40 counter0(this, name + ".counter0"),
41 counter1(this, name + ".counter1"),
42 counter2(this, name + ".counter2")
43{
44 counter[0] = &counter0;
45 counter[1] = &counter0;
46 counter[2] = &counter0;
47}
48
49void
50Intel8254Timer::writeControl(const CtrlReg data)
51{
52 int sel = data.sel;
53
54 if (sel == ReadBackCommand)
55 panic("PITimer Read-Back Command is not implemented.\n");
56
57 if (data.rw == LatchCommand)
58 counter[sel]->latchCount();
59 else {
60 counter[sel]->setRW(data.rw);
61 counter[sel]->setMode(data.mode);
62 counter[sel]->setBCD(data.bcd);
63 }
64}
65
66void
67Intel8254Timer::serialize(const string &base, ostream &os)
68{
69 // serialize the counters
70 counter0.serialize(base + ".counter0", os);
71 counter1.serialize(base + ".counter1", os);
72 counter2.serialize(base + ".counter2", os);
73}
74
75void
76Intel8254Timer::unserialize(const string &base, Checkpoint *cp,
77 const string &section)
78{
79 // unserialze the counters
80 counter0.unserialize(base + ".counter0", cp, section);
81 counter1.unserialize(base + ".counter1", cp, section);
82 counter2.unserialize(base + ".counter2", cp, section);
83}
84
85Intel8254Timer::Counter::Counter(Intel8254Timer *p, const string &name)
86 : _name(name), event(this), count(0), latched_count(0), period(0),
87 mode(0), output_high(false), latch_on(false), read_byte(LSB),
88 write_byte(LSB), parent(p)
89{
90
91}
92
93void
94Intel8254Timer::Counter::latchCount()
95{
96 // behave like a real latch
97 if(!latch_on) {
98 latch_on = true;
99 read_byte = LSB;
100 latched_count = count;
101 }
102}
103
104uint8_t
105Intel8254Timer::Counter::read()
106{
107 if (latch_on) {
108 switch (read_byte) {
109 case LSB:
110 read_byte = MSB;
111 return (uint8_t)latched_count;
112 break;
113 case MSB:
114 read_byte = LSB;
115 latch_on = false;
116 return latched_count >> 8;
117 break;
118 default:
119 panic("Shouldn't be here");
120 }
121 } else {
122 switch (read_byte) {
123 case LSB:
124 read_byte = MSB;
125 return (uint8_t)count;
126 break;
127 case MSB:
128 read_byte = LSB;
129 return count >> 8;
130 break;
131 default:
132 panic("Shouldn't be here");
133 }
134 }
135}
136
137void
138Intel8254Timer::Counter::write(const uint8_t data)
139{
140 switch (write_byte) {
141 case LSB:
142 count = (count & 0xFF00) | data;
143
144 if (event.scheduled())
145 parent->deschedule(event);
146 output_high = false;
147 write_byte = MSB;
148 break;
149
150 case MSB:
151 count = (count & 0x00FF) | (data << 8);
152 // In the RateGen or SquareWave modes, the timer wraps around and
153 // triggers on a value of 1, not 0.
154 if (mode == RateGen || mode == SquareWave)
155 period = count - 1;
156 else
157 period = count;
158
159 if (period > 0)
160 event.setTo(period);
161
162 write_byte = LSB;
163 break;
164 }
165}
166
167void
168Intel8254Timer::Counter::setRW(int rw_val)
169{
170 if (rw_val != TwoPhase)
171 panic("Only LSB/MSB read/write is implemented.\n");
172}
173
174void
175Intel8254Timer::Counter::setMode(int mode_val)
176{
177 if(mode_val != InitTc && mode_val != RateGen &&
178 mode_val != SquareWave)
179 panic("PIT mode %#x is not implemented: \n", mode_val);
180
181 mode = mode_val;
182}
183
184void
185Intel8254Timer::Counter::setBCD(int bcd_val)
186{
187 if (bcd_val)
188 panic("PITimer does not implement BCD counts.\n");
189}
190
191bool
192Intel8254Timer::Counter::outputHigh()
193{
194 return output_high;
195}
196
197void
198Intel8254Timer::Counter::serialize(const string &base, ostream &os)
199{
200 paramOut(os, base + ".count", count);
201 paramOut(os, base + ".latched_count", latched_count);
202 paramOut(os, base + ".period", period);
203 paramOut(os, base + ".mode", mode);
204 paramOut(os, base + ".output_high", output_high);
205 paramOut(os, base + ".latch_on", latch_on);
206 paramOut(os, base + ".read_byte", read_byte);
207 paramOut(os, base + ".write_byte", write_byte);
208
209 Tick event_tick = 0;
210 if (event.scheduled())
211 event_tick = event.when();
212 paramOut(os, base + ".event_tick", event_tick);
213}
214
215void
216Intel8254Timer::Counter::unserialize(const string &base, Checkpoint *cp,
217 const string &section)
218{
219 paramIn(cp, section, base + ".count", count);
220 paramIn(cp, section, base + ".latched_count", latched_count);
221 paramIn(cp, section, base + ".period", period);
222 paramIn(cp, section, base + ".mode", mode);
223 paramIn(cp, section, base + ".output_high", output_high);
224 paramIn(cp, section, base + ".latch_on", latch_on);
225 paramIn(cp, section, base + ".read_byte", read_byte);
226 paramIn(cp, section, base + ".write_byte", write_byte);
227
228 Tick event_tick;
229 paramIn(cp, section, base + ".event_tick", event_tick);
230 if (event_tick)
231 parent->schedule(event, event_tick);
232}
233
234Intel8254Timer::Counter::CounterEvent::CounterEvent(Counter* c_ptr)
235{
236 interval = (Tick)(Clock::Float::s / 1193180.0);
237 counter = c_ptr;
238}
239
240void
241Intel8254Timer::Counter::CounterEvent::process()
242{
243 DPRINTF(Intel8254Timer, "Timer Interrupt\n");
244 switch (counter->mode) {
245 case InitTc:
246 counter->output_high = true;
247 break;
248 case RateGen:
249 case SquareWave:
250 setTo(counter->period);
251 break;
252 default:
253 panic("Unimplemented PITimer mode.\n");
254 }
255}
256
257void
258Intel8254Timer::Counter::CounterEvent::setTo(int clocks)
259{
260 if (clocks == 0)
261 panic("Timer can't be set to go off instantly.\n");
262 DPRINTF(Intel8254Timer, "Timer set to curTick + %d\n",
263 clocks * interval);
264 counter->parent->schedule(this, curTick + clocks * interval);
265}
266
267const char *
268Intel8254Timer::Counter::CounterEvent::description() const
269{
270 return "tsunami 8254 Interval timer";
271}