intel_8254_timer.cc revision 5444:d5d0ac0b6d58
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(const string &name) 39 : _name(name), counter0(name + ".counter0"), counter1(name + ".counter1"), 40 counter2(name + ".counter2") 41{ 42 counter[0] = &counter0; 43 counter[1] = &counter0; 44 counter[2] = &counter0; 45} 46 47void 48Intel8254Timer::writeControl(const CtrlReg data) 49{ 50 int sel = data.sel; 51 52 if (sel == ReadBackCommand) 53 panic("PITimer Read-Back Command is not implemented.\n"); 54 55 if (data.rw == LatchCommand) 56 counter[sel]->latchCount(); 57 else { 58 counter[sel]->setRW(data.rw); 59 counter[sel]->setMode(data.mode); 60 counter[sel]->setBCD(data.bcd); 61 } 62} 63 64void 65Intel8254Timer::serialize(const string &base, ostream &os) 66{ 67 // serialize the counters 68 counter0.serialize(base + ".counter0", os); 69 counter1.serialize(base + ".counter1", os); 70 counter2.serialize(base + ".counter2", os); 71} 72 73void 74Intel8254Timer::unserialize(const string &base, Checkpoint *cp, 75 const string §ion) 76{ 77 // unserialze the counters 78 counter0.unserialize(base + ".counter0", cp, section); 79 counter1.unserialize(base + ".counter1", cp, section); 80 counter2.unserialize(base + ".counter2", cp, section); 81} 82 83Intel8254Timer::Counter::Counter(const string &name) 84 : _name(name), event(this), count(0), latched_count(0), period(0), 85 mode(0), output_high(false), latch_on(false), read_byte(LSB), 86 write_byte(LSB) 87{ 88 89} 90 91void 92Intel8254Timer::Counter::latchCount() 93{ 94 // behave like a real latch 95 if(!latch_on) { 96 latch_on = true; 97 read_byte = LSB; 98 latched_count = count; 99 } 100} 101 102uint8_t 103Intel8254Timer::Counter::read() 104{ 105 if (latch_on) { 106 switch (read_byte) { 107 case LSB: 108 read_byte = MSB; 109 return (uint8_t)latched_count; 110 break; 111 case MSB: 112 read_byte = LSB; 113 latch_on = false; 114 return latched_count >> 8; 115 break; 116 default: 117 panic("Shouldn't be here"); 118 } 119 } else { 120 switch (read_byte) { 121 case LSB: 122 read_byte = MSB; 123 return (uint8_t)count; 124 break; 125 case MSB: 126 read_byte = LSB; 127 return count >> 8; 128 break; 129 default: 130 panic("Shouldn't be here"); 131 } 132 } 133} 134 135void 136Intel8254Timer::Counter::write(const uint8_t data) 137{ 138 switch (write_byte) { 139 case LSB: 140 count = (count & 0xFF00) | data; 141 142 if (event.scheduled()) 143 event.deschedule(); 144 output_high = false; 145 write_byte = MSB; 146 break; 147 148 case MSB: 149 count = (count & 0x00FF) | (data << 8); 150 // In the RateGen or SquareWave modes, the timer wraps around and 151 // triggers on a value of 1, not 0. 152 if (mode == RateGen || mode == SquareWave) 153 period = count - 1; 154 else 155 period = count; 156 157 if (period > 0) 158 event.setTo(period); 159 160 write_byte = LSB; 161 break; 162 } 163} 164 165void 166Intel8254Timer::Counter::setRW(int rw_val) 167{ 168 if (rw_val != TwoPhase) 169 panic("Only LSB/MSB read/write is implemented.\n"); 170} 171 172void 173Intel8254Timer::Counter::setMode(int mode_val) 174{ 175 if(mode_val != InitTc && mode_val != RateGen && 176 mode_val != SquareWave) 177 panic("PIT mode %#x is not implemented: \n", mode_val); 178 179 mode = mode_val; 180} 181 182void 183Intel8254Timer::Counter::setBCD(int bcd_val) 184{ 185 if (bcd_val) 186 panic("PITimer does not implement BCD counts.\n"); 187} 188 189bool 190Intel8254Timer::Counter::outputHigh() 191{ 192 return output_high; 193} 194 195void 196Intel8254Timer::Counter::serialize(const string &base, ostream &os) 197{ 198 paramOut(os, base + ".count", count); 199 paramOut(os, base + ".latched_count", latched_count); 200 paramOut(os, base + ".period", period); 201 paramOut(os, base + ".mode", mode); 202 paramOut(os, base + ".output_high", output_high); 203 paramOut(os, base + ".latch_on", latch_on); 204 paramOut(os, base + ".read_byte", read_byte); 205 paramOut(os, base + ".write_byte", write_byte); 206 207 Tick event_tick = 0; 208 if (event.scheduled()) 209 event_tick = event.when(); 210 paramOut(os, base + ".event_tick", event_tick); 211} 212 213void 214Intel8254Timer::Counter::unserialize(const string &base, Checkpoint *cp, 215 const string §ion) 216{ 217 paramIn(cp, section, base + ".count", count); 218 paramIn(cp, section, base + ".latched_count", latched_count); 219 paramIn(cp, section, base + ".period", period); 220 paramIn(cp, section, base + ".mode", mode); 221 paramIn(cp, section, base + ".output_high", output_high); 222 paramIn(cp, section, base + ".latch_on", latch_on); 223 paramIn(cp, section, base + ".read_byte", read_byte); 224 paramIn(cp, section, base + ".write_byte", write_byte); 225 226 Tick event_tick; 227 paramIn(cp, section, base + ".event_tick", event_tick); 228 if (event_tick) 229 event.schedule(event_tick); 230} 231 232Intel8254Timer::Counter::CounterEvent::CounterEvent(Counter* c_ptr) 233 : Event(&mainEventQueue) 234{ 235 interval = (Tick)(Clock::Float::s / 1193180.0); 236 counter = c_ptr; 237} 238 239void 240Intel8254Timer::Counter::CounterEvent::process() 241{ 242 DPRINTF(Intel8254Timer, "Timer Interrupt\n"); 243 switch (counter->mode) { 244 case InitTc: 245 counter->output_high = true; 246 break; 247 case RateGen: 248 case SquareWave: 249 setTo(counter->period); 250 break; 251 default: 252 panic("Unimplemented PITimer mode.\n"); 253 } 254} 255 256void 257Intel8254Timer::Counter::CounterEvent::setTo(int clocks) 258{ 259 if (clocks == 0) 260 panic("Timer can't be set to go off instantly.\n"); 261 DPRINTF(Intel8254Timer, "Timer set to curTick + %d\n", 262 clocks * interval); 263 schedule(curTick + clocks * interval); 264} 265 266const char * 267Intel8254Timer::Counter::CounterEvent::description() const 268{ 269 return "tsunami 8254 Interval timer"; 270} 271