mc146818.cc revision 10631
15392Sgblack@eecs.umich.edu/* 25392Sgblack@eecs.umich.edu * Copyright (c) 2004-2005 The Regents of The University of Michigan 35392Sgblack@eecs.umich.edu * All rights reserved. 45392Sgblack@eecs.umich.edu * 55392Sgblack@eecs.umich.edu * Redistribution and use in source and binary forms, with or without 65392Sgblack@eecs.umich.edu * modification, are permitted provided that the following conditions are 75392Sgblack@eecs.umich.edu * met: redistributions of source code must retain the above copyright 85392Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer; 95392Sgblack@eecs.umich.edu * redistributions in binary form must reproduce the above copyright 105392Sgblack@eecs.umich.edu * notice, this list of conditions and the following disclaimer in the 115392Sgblack@eecs.umich.edu * documentation and/or other materials provided with the distribution; 125392Sgblack@eecs.umich.edu * neither the name of the copyright holders nor the names of its 135392Sgblack@eecs.umich.edu * contributors may be used to endorse or promote products derived from 145392Sgblack@eecs.umich.edu * this software without specific prior written permission. 155392Sgblack@eecs.umich.edu * 165392Sgblack@eecs.umich.edu * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 175392Sgblack@eecs.umich.edu * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 185392Sgblack@eecs.umich.edu * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 195392Sgblack@eecs.umich.edu * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 205392Sgblack@eecs.umich.edu * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 215392Sgblack@eecs.umich.edu * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 225392Sgblack@eecs.umich.edu * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 235392Sgblack@eecs.umich.edu * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 245392Sgblack@eecs.umich.edu * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 255392Sgblack@eecs.umich.edu * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 265392Sgblack@eecs.umich.edu * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 275392Sgblack@eecs.umich.edu * 285392Sgblack@eecs.umich.edu * Authors: Ali Saidi 295392Sgblack@eecs.umich.edu * Andrew Schultz 305392Sgblack@eecs.umich.edu * Miguel Serrano 315392Sgblack@eecs.umich.edu */ 325392Sgblack@eecs.umich.edu 335392Sgblack@eecs.umich.edu#include <sys/time.h> 345392Sgblack@eecs.umich.edu 358229Snate@binkert.org#include <ctime> 365392Sgblack@eecs.umich.edu#include <string> 375392Sgblack@eecs.umich.edu 385813Sgblack@eecs.umich.edu#include "base/bitfield.hh" 395392Sgblack@eecs.umich.edu#include "base/time.hh" 405392Sgblack@eecs.umich.edu#include "base/trace.hh" 418232Snate@binkert.org#include "debug/MC146818.hh" 425392Sgblack@eecs.umich.edu#include "dev/mc146818.hh" 435392Sgblack@eecs.umich.edu#include "dev/rtcreg.h" 445392Sgblack@eecs.umich.edu 455392Sgblack@eecs.umich.eduusing namespace std; 465392Sgblack@eecs.umich.edu 476620Sgblack@eecs.umich.edustatic uint8_t 486620Sgblack@eecs.umich.edubcdize(uint8_t val) 495392Sgblack@eecs.umich.edu{ 506620Sgblack@eecs.umich.edu uint8_t result; 516620Sgblack@eecs.umich.edu result = val % 10; 526620Sgblack@eecs.umich.edu result += (val / 10) << 4; 536620Sgblack@eecs.umich.edu return result; 546620Sgblack@eecs.umich.edu} 555392Sgblack@eecs.umich.edu 566621Sgblack@eecs.umich.edustatic uint8_t 576621Sgblack@eecs.umich.eduunbcdize(uint8_t val) 586621Sgblack@eecs.umich.edu{ 596621Sgblack@eecs.umich.edu uint8_t result; 606621Sgblack@eecs.umich.edu result = val & 0xf; 616621Sgblack@eecs.umich.edu result += (val >> 4) * 10; 626621Sgblack@eecs.umich.edu return result; 636621Sgblack@eecs.umich.edu} 646621Sgblack@eecs.umich.edu 656620Sgblack@eecs.umich.eduvoid 666620Sgblack@eecs.umich.eduMC146818::setTime(const struct tm time) 676620Sgblack@eecs.umich.edu{ 686620Sgblack@eecs.umich.edu curTime = time; 695392Sgblack@eecs.umich.edu year = time.tm_year; 705392Sgblack@eecs.umich.edu // Unix is 0-11 for month, data seet says start at 1 715392Sgblack@eecs.umich.edu mon = time.tm_mon + 1; 725392Sgblack@eecs.umich.edu mday = time.tm_mday; 735392Sgblack@eecs.umich.edu hour = time.tm_hour; 745392Sgblack@eecs.umich.edu min = time.tm_min; 755392Sgblack@eecs.umich.edu sec = time.tm_sec; 765392Sgblack@eecs.umich.edu 775392Sgblack@eecs.umich.edu // Datasheet says 1 is sunday 785392Sgblack@eecs.umich.edu wday = time.tm_wday + 1; 795392Sgblack@eecs.umich.edu 809730Sandreas@sandberg.pp.se if (!stat_regB.dm) { 816620Sgblack@eecs.umich.edu // The datasheet says that the year field can be either BCD or 826620Sgblack@eecs.umich.edu // years since 1900. Linux seems to be happy with years since 836620Sgblack@eecs.umich.edu // 1900. 846620Sgblack@eecs.umich.edu year = bcdize(year % 100); 856620Sgblack@eecs.umich.edu mon = bcdize(mon); 866620Sgblack@eecs.umich.edu mday = bcdize(mday); 876620Sgblack@eecs.umich.edu hour = bcdize(hour); 886620Sgblack@eecs.umich.edu min = bcdize(min); 896620Sgblack@eecs.umich.edu sec = bcdize(sec); 906620Sgblack@eecs.umich.edu } 916620Sgblack@eecs.umich.edu} 926620Sgblack@eecs.umich.edu 936620Sgblack@eecs.umich.eduMC146818::MC146818(EventManager *em, const string &n, const struct tm time, 946620Sgblack@eecs.umich.edu bool bcd, Tick frequency) 956620Sgblack@eecs.umich.edu : EventManager(em), _name(n), event(this, frequency), tickEvent(this) 966620Sgblack@eecs.umich.edu{ 976620Sgblack@eecs.umich.edu memset(clock_data, 0, sizeof(clock_data)); 989730Sandreas@sandberg.pp.se 999730Sandreas@sandberg.pp.se stat_regA = 0; 1009730Sandreas@sandberg.pp.se stat_regA.dv = RTCA_DV_32768HZ; 1019730Sandreas@sandberg.pp.se stat_regA.rs = RTCA_RS_1024HZ; 1029730Sandreas@sandberg.pp.se 1039730Sandreas@sandberg.pp.se stat_regB = 0; 1049730Sandreas@sandberg.pp.se stat_regB.pie = 1; 1059730Sandreas@sandberg.pp.se stat_regB.format24h = 1; 1069730Sandreas@sandberg.pp.se stat_regB.dm = bcd ? 0 : 1; 1076620Sgblack@eecs.umich.edu 1086620Sgblack@eecs.umich.edu setTime(time); 1095392Sgblack@eecs.umich.edu DPRINTFN("Real-time clock set to %s", asctime(&time)); 1105392Sgblack@eecs.umich.edu} 1115392Sgblack@eecs.umich.edu 1125606Snate@binkert.orgMC146818::~MC146818() 1135606Snate@binkert.org{ 1147683Ssteve.reinhardt@amd.com deschedule(tickEvent); 1157683Ssteve.reinhardt@amd.com deschedule(event); 1165606Snate@binkert.org} 1175606Snate@binkert.org 1189730Sandreas@sandberg.pp.sebool 1199730Sandreas@sandberg.pp.seMC146818::rega_dv_disabled(const RtcRegA ®) 1209730Sandreas@sandberg.pp.se{ 1219730Sandreas@sandberg.pp.se return reg.dv == RTCA_DV_DISABLED0 || 1229730Sandreas@sandberg.pp.se reg.dv == RTCA_DV_DISABLED1; 1239730Sandreas@sandberg.pp.se} 1249730Sandreas@sandberg.pp.se 1255392Sgblack@eecs.umich.eduvoid 12610631Scdirik@micron.comMC146818::startup() 12710631Scdirik@micron.com{ 12810631Scdirik@micron.com assert(!event.scheduled()); 12910631Scdirik@micron.com assert(!tickEvent.scheduled()); 13010631Scdirik@micron.com schedule(event, curTick() + event.offset); 13110631Scdirik@micron.com schedule(tickEvent, curTick() + tickEvent.offset); 13210631Scdirik@micron.com} 13310631Scdirik@micron.com 13410631Scdirik@micron.comvoid 1355392Sgblack@eecs.umich.eduMC146818::writeData(const uint8_t addr, const uint8_t data) 1365392Sgblack@eecs.umich.edu{ 1379730Sandreas@sandberg.pp.se bool panic_unsupported(false); 1389730Sandreas@sandberg.pp.se 1396621Sgblack@eecs.umich.edu if (addr < RTC_STAT_REGA) { 1405392Sgblack@eecs.umich.edu clock_data[addr] = data; 1416621Sgblack@eecs.umich.edu curTime.tm_sec = unbcdize(sec); 1426621Sgblack@eecs.umich.edu curTime.tm_min = unbcdize(min); 1436621Sgblack@eecs.umich.edu curTime.tm_hour = unbcdize(hour); 1446621Sgblack@eecs.umich.edu curTime.tm_mday = unbcdize(mday); 1456621Sgblack@eecs.umich.edu curTime.tm_mon = unbcdize(mon) - 1; 1466621Sgblack@eecs.umich.edu curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950; 1476621Sgblack@eecs.umich.edu curTime.tm_wday = unbcdize(wday) - 1; 1486621Sgblack@eecs.umich.edu } else { 1495392Sgblack@eecs.umich.edu switch (addr) { 1509730Sandreas@sandberg.pp.se case RTC_STAT_REGA: { 1519730Sandreas@sandberg.pp.se RtcRegA old_rega(stat_regA); 1529730Sandreas@sandberg.pp.se stat_regA = data; 1539730Sandreas@sandberg.pp.se // The "update in progress" bit is read only. 1549730Sandreas@sandberg.pp.se stat_regA.uip = old_rega; 1559730Sandreas@sandberg.pp.se 1569731Sandreas@sandberg.pp.se if (!rega_dv_disabled(stat_regA) && 1579731Sandreas@sandberg.pp.se stat_regA.dv != RTCA_DV_32768HZ) { 1589730Sandreas@sandberg.pp.se inform("RTC: Unimplemented divider configuration: %i\n", 1599730Sandreas@sandberg.pp.se stat_regA.dv); 1609730Sandreas@sandberg.pp.se panic_unsupported = true; 1619730Sandreas@sandberg.pp.se } 1629730Sandreas@sandberg.pp.se 1639730Sandreas@sandberg.pp.se if (stat_regA.rs != RTCA_RS_1024HZ) { 1649730Sandreas@sandberg.pp.se inform("RTC: Unimplemented interrupt rate: %i\n", 1659730Sandreas@sandberg.pp.se stat_regA.rs); 1669730Sandreas@sandberg.pp.se panic_unsupported = true; 1679730Sandreas@sandberg.pp.se } 1689731Sandreas@sandberg.pp.se 1699731Sandreas@sandberg.pp.se if (rega_dv_disabled(stat_regA)) { 1709731Sandreas@sandberg.pp.se // The divider is disabled, make sure that we don't 1719731Sandreas@sandberg.pp.se // schedule any ticks. 1729731Sandreas@sandberg.pp.se if (tickEvent.scheduled()) 1739731Sandreas@sandberg.pp.se deschedule(tickEvent); 1749731Sandreas@sandberg.pp.se } else if (rega_dv_disabled(old_rega)) { 1759739Sandreas@sandberg.pp.se // According to the specification, the next tick 1769739Sandreas@sandberg.pp.se // happens after 0.5s when the divider chain goes 1779739Sandreas@sandberg.pp.se // from reset to active. So, we simply schedule the 1789739Sandreas@sandberg.pp.se // tick after 0.5s. 1799731Sandreas@sandberg.pp.se assert(!tickEvent.scheduled()); 1809731Sandreas@sandberg.pp.se schedule(tickEvent, curTick() + SimClock::Int::s / 2); 1819731Sandreas@sandberg.pp.se } 1829730Sandreas@sandberg.pp.se } break; 1835392Sgblack@eecs.umich.edu case RTC_STAT_REGB: 1849730Sandreas@sandberg.pp.se stat_regB = data; 1859730Sandreas@sandberg.pp.se if (stat_regB.aie || stat_regB.uie) { 1869730Sandreas@sandberg.pp.se inform("RTC: Unimplemented interrupt configuration: %s %s\n", 1879730Sandreas@sandberg.pp.se stat_regB.aie ? "alarm" : "", 1889730Sandreas@sandberg.pp.se stat_regB.uie ? "update" : ""); 1899730Sandreas@sandberg.pp.se panic_unsupported = true; 1909730Sandreas@sandberg.pp.se } 1919730Sandreas@sandberg.pp.se 1929730Sandreas@sandberg.pp.se if (stat_regB.dm) { 1939730Sandreas@sandberg.pp.se inform("RTC: The binary interface is not fully implemented.\n"); 1949730Sandreas@sandberg.pp.se panic_unsupported = true; 1959730Sandreas@sandberg.pp.se } 1969730Sandreas@sandberg.pp.se 1979730Sandreas@sandberg.pp.se if (!stat_regB.format24h) { 1989730Sandreas@sandberg.pp.se inform("RTC: The 12h time format not supported.\n"); 1999730Sandreas@sandberg.pp.se panic_unsupported = true; 2009730Sandreas@sandberg.pp.se } 2019730Sandreas@sandberg.pp.se 2029730Sandreas@sandberg.pp.se if (stat_regB.dse) { 2039730Sandreas@sandberg.pp.se inform("RTC: Automatic daylight saving time not supported.\n"); 2049730Sandreas@sandberg.pp.se panic_unsupported = true; 2059730Sandreas@sandberg.pp.se } 2069730Sandreas@sandberg.pp.se 2079730Sandreas@sandberg.pp.se if (stat_regB.pie) { 2085392Sgblack@eecs.umich.edu if (!event.scheduled()) 2095392Sgblack@eecs.umich.edu event.scheduleIntr(); 2105392Sgblack@eecs.umich.edu } else { 2115392Sgblack@eecs.umich.edu if (event.scheduled()) 2125606Snate@binkert.org deschedule(event); 2135392Sgblack@eecs.umich.edu } 2145392Sgblack@eecs.umich.edu break; 2155392Sgblack@eecs.umich.edu case RTC_STAT_REGC: 2165392Sgblack@eecs.umich.edu case RTC_STAT_REGD: 2175392Sgblack@eecs.umich.edu panic("RTC status registers C and D are not implemented.\n"); 2185392Sgblack@eecs.umich.edu break; 2195392Sgblack@eecs.umich.edu } 2205392Sgblack@eecs.umich.edu } 2219730Sandreas@sandberg.pp.se 2229730Sandreas@sandberg.pp.se if (panic_unsupported) 2239730Sandreas@sandberg.pp.se panic("Unimplemented RTC configuration!\n"); 2249730Sandreas@sandberg.pp.se 2255392Sgblack@eecs.umich.edu} 2265392Sgblack@eecs.umich.edu 2275392Sgblack@eecs.umich.eduuint8_t 2285392Sgblack@eecs.umich.eduMC146818::readData(uint8_t addr) 2295392Sgblack@eecs.umich.edu{ 2305392Sgblack@eecs.umich.edu if (addr < RTC_STAT_REGA) 2315392Sgblack@eecs.umich.edu return clock_data[addr]; 2325392Sgblack@eecs.umich.edu else { 2335392Sgblack@eecs.umich.edu switch (addr) { 2345392Sgblack@eecs.umich.edu case RTC_STAT_REGA: 2355392Sgblack@eecs.umich.edu // toggle UIP bit for linux 2369730Sandreas@sandberg.pp.se stat_regA.uip = !stat_regA.uip; 2375392Sgblack@eecs.umich.edu return stat_regA; 2385392Sgblack@eecs.umich.edu break; 2395392Sgblack@eecs.umich.edu case RTC_STAT_REGB: 2405392Sgblack@eecs.umich.edu return stat_regB; 2415392Sgblack@eecs.umich.edu break; 2425392Sgblack@eecs.umich.edu case RTC_STAT_REGC: 2435392Sgblack@eecs.umich.edu case RTC_STAT_REGD: 2445392Sgblack@eecs.umich.edu return 0x00; 2455392Sgblack@eecs.umich.edu break; 2465392Sgblack@eecs.umich.edu default: 2475392Sgblack@eecs.umich.edu panic("Shouldn't be here"); 2485392Sgblack@eecs.umich.edu } 2495392Sgblack@eecs.umich.edu } 2505392Sgblack@eecs.umich.edu} 2515392Sgblack@eecs.umich.edu 2526620Sgblack@eecs.umich.eduvoid 2536620Sgblack@eecs.umich.eduMC146818::tickClock() 2546620Sgblack@eecs.umich.edu{ 2559731Sandreas@sandberg.pp.se assert(!rega_dv_disabled(stat_regA)); 2569731Sandreas@sandberg.pp.se 2579730Sandreas@sandberg.pp.se if (stat_regB.set) 2586620Sgblack@eecs.umich.edu return; 2596620Sgblack@eecs.umich.edu time_t calTime = mkutctime(&curTime); 2606620Sgblack@eecs.umich.edu calTime++; 2616620Sgblack@eecs.umich.edu setTime(*gmtime(&calTime)); 2626620Sgblack@eecs.umich.edu} 2636620Sgblack@eecs.umich.edu 2645392Sgblack@eecs.umich.eduvoid 2655392Sgblack@eecs.umich.eduMC146818::serialize(const string &base, ostream &os) 2665392Sgblack@eecs.umich.edu{ 2679730Sandreas@sandberg.pp.se uint8_t regA_serial(stat_regA); 2689730Sandreas@sandberg.pp.se uint8_t regB_serial(stat_regB); 2699730Sandreas@sandberg.pp.se 2705392Sgblack@eecs.umich.edu arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data)); 2719730Sandreas@sandberg.pp.se paramOut(os, base + ".stat_regA", (uint8_t)regA_serial); 2729730Sandreas@sandberg.pp.se paramOut(os, base + ".stat_regB", (uint8_t)regB_serial); 2736677SBrad.Beckmann@amd.com 2746677SBrad.Beckmann@amd.com // 2756677SBrad.Beckmann@amd.com // save the timer tick and rtc clock tick values to correctly reschedule 2766677SBrad.Beckmann@amd.com // them during unserialize 2776677SBrad.Beckmann@amd.com // 2787823Ssteve.reinhardt@amd.com Tick rtcTimerInterruptTickOffset = event.when() - curTick(); 2796677SBrad.Beckmann@amd.com SERIALIZE_SCALAR(rtcTimerInterruptTickOffset); 2808593Snilay@cs.wisc.edu Tick rtcClockTickOffset = tickEvent.when() - curTick(); 2816677SBrad.Beckmann@amd.com SERIALIZE_SCALAR(rtcClockTickOffset); 2825392Sgblack@eecs.umich.edu} 2835392Sgblack@eecs.umich.edu 2845392Sgblack@eecs.umich.eduvoid 2855392Sgblack@eecs.umich.eduMC146818::unserialize(const string &base, Checkpoint *cp, 2865392Sgblack@eecs.umich.edu const string §ion) 2875392Sgblack@eecs.umich.edu{ 2889730Sandreas@sandberg.pp.se uint8_t tmp8; 2899730Sandreas@sandberg.pp.se 2905392Sgblack@eecs.umich.edu arrayParamIn(cp, section, base + ".clock_data", clock_data, 2915392Sgblack@eecs.umich.edu sizeof(clock_data)); 2929730Sandreas@sandberg.pp.se 2939730Sandreas@sandberg.pp.se paramIn(cp, section, base + ".stat_regA", tmp8); 2949730Sandreas@sandberg.pp.se stat_regA = tmp8; 2959730Sandreas@sandberg.pp.se paramIn(cp, section, base + ".stat_regB", tmp8); 2969730Sandreas@sandberg.pp.se stat_regB = tmp8; 2975392Sgblack@eecs.umich.edu 2986677SBrad.Beckmann@amd.com // 2996677SBrad.Beckmann@amd.com // properly schedule the timer and rtc clock events 3006677SBrad.Beckmann@amd.com // 3016677SBrad.Beckmann@amd.com Tick rtcTimerInterruptTickOffset; 3026677SBrad.Beckmann@amd.com UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset); 30310631Scdirik@micron.com event.offset = rtcTimerInterruptTickOffset; 3046677SBrad.Beckmann@amd.com Tick rtcClockTickOffset; 3056677SBrad.Beckmann@amd.com UNSERIALIZE_SCALAR(rtcClockTickOffset); 30610631Scdirik@micron.com tickEvent.offset = rtcClockTickOffset; 3075392Sgblack@eecs.umich.edu} 3085392Sgblack@eecs.umich.edu 3095392Sgblack@eecs.umich.eduMC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i) 31010631Scdirik@micron.com : parent(_parent), interval(i), offset(i) 3115392Sgblack@eecs.umich.edu{ 3125392Sgblack@eecs.umich.edu DPRINTF(MC146818, "RTC Event Initilizing\n"); 3135392Sgblack@eecs.umich.edu} 3145392Sgblack@eecs.umich.edu 3155392Sgblack@eecs.umich.eduvoid 3165392Sgblack@eecs.umich.eduMC146818::RTCEvent::scheduleIntr() 3175392Sgblack@eecs.umich.edu{ 3187823Ssteve.reinhardt@amd.com parent->schedule(this, curTick() + interval); 3195392Sgblack@eecs.umich.edu} 3205392Sgblack@eecs.umich.edu 3215392Sgblack@eecs.umich.eduvoid 3225392Sgblack@eecs.umich.eduMC146818::RTCEvent::process() 3235392Sgblack@eecs.umich.edu{ 3245392Sgblack@eecs.umich.edu DPRINTF(MC146818, "RTC Timer Interrupt\n"); 3257823Ssteve.reinhardt@amd.com parent->schedule(this, curTick() + interval); 3265392Sgblack@eecs.umich.edu parent->handleEvent(); 3275392Sgblack@eecs.umich.edu} 3285392Sgblack@eecs.umich.edu 3295392Sgblack@eecs.umich.educonst char * 3305392Sgblack@eecs.umich.eduMC146818::RTCEvent::description() const 3315392Sgblack@eecs.umich.edu{ 3325392Sgblack@eecs.umich.edu return "RTC interrupt"; 3335392Sgblack@eecs.umich.edu} 3346620Sgblack@eecs.umich.edu 3356620Sgblack@eecs.umich.eduvoid 3366620Sgblack@eecs.umich.eduMC146818::RTCTickEvent::process() 3376620Sgblack@eecs.umich.edu{ 3386620Sgblack@eecs.umich.edu DPRINTF(MC146818, "RTC clock tick\n"); 3397823Ssteve.reinhardt@amd.com parent->schedule(this, curTick() + SimClock::Int::s); 3406620Sgblack@eecs.umich.edu parent->tickClock(); 3416620Sgblack@eecs.umich.edu} 3426620Sgblack@eecs.umich.edu 3436620Sgblack@eecs.umich.educonst char * 3446620Sgblack@eecs.umich.eduMC146818::RTCTickEvent::description() const 3456620Sgblack@eecs.umich.edu{ 3466620Sgblack@eecs.umich.edu return "RTC clock tick"; 3476620Sgblack@eecs.umich.edu} 348