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/*
* Copyright (c) 2004-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "dev/mc146818.hh"
#include <sys/time.h>
#include <ctime>
#include <string>
#include "base/bitfield.hh"
#include "base/time.hh"
#include "base/trace.hh"
#include "debug/MC146818.hh"
#include "dev/rtcreg.h"
namespace gem5
{
static uint8_t
bcdize(uint8_t val)
{
uint8_t result;
result = val % 10;
result += (val / 10) << 4;
return result;
}
static uint8_t
unbcdize(uint8_t val)
{
uint8_t result;
result = val & 0xf;
result += (val >> 4) * 10;
return result;
}
void
MC146818::setTime(const struct tm time)
{
curTime = time;
year = time.tm_year;
// Unix is 0-11 for month, data seet says start at 1
mon = time.tm_mon + 1;
mday = time.tm_mday;
hour = time.tm_hour;
min = time.tm_min;
sec = time.tm_sec;
// Datasheet says 1 is sunday
wday = time.tm_wday + 1;
if (!stat_regB.dm) {
// The datasheet says that the year field can be either BCD or
// years since 1900. Linux seems to be happy with years since
// 1900.
year = bcdize(year % 100);
mon = bcdize(mon);
mday = bcdize(mday);
hour = bcdize(hour);
min = bcdize(min);
sec = bcdize(sec);
}
}
MC146818::MC146818(EventManager *em, const std::string &n,
const struct tm time, bool bcd, Tick frequency)
: EventManager(em), _name(n), event(this, frequency), tickEvent(this)
{
memset(clock_data, 0, sizeof(clock_data));
stat_regA = 0;
stat_regA.dv = RTCA_DV_32768HZ;
stat_regA.rs = RTCA_RS_1024HZ;
stat_regB = 0;
stat_regB.pie = 1;
stat_regB.format24h = 1;
stat_regB.dm = bcd ? 0 : 1;
setTime(time);
DPRINTFN("Real-time clock set to %s", asctime(&time));
}
MC146818::~MC146818()
{
deschedule(tickEvent);
deschedule(event);
}
bool
MC146818::rega_dv_disabled(const RtcRegA &reg)
{
return reg.dv == RTCA_DV_DISABLED0 ||
reg.dv == RTCA_DV_DISABLED1;
}
void
MC146818::startup()
{
assert(!event.scheduled());
assert(!tickEvent.scheduled());
if (stat_regB.pie)
schedule(event, curTick() + event.offset);
if (!rega_dv_disabled(stat_regA))
schedule(tickEvent, curTick() + tickEvent.offset);
}
void
MC146818::writeData(const uint8_t addr, const uint8_t data)
{
bool panic_unsupported(false);
if (addr < RTC_STAT_REGA) {
clock_data[addr] = data;
curTime.tm_sec = unbcdize(sec);
curTime.tm_min = unbcdize(min);
curTime.tm_hour = unbcdize(hour);
curTime.tm_mday = unbcdize(mday);
curTime.tm_mon = unbcdize(mon) - 1;
curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950;
curTime.tm_wday = unbcdize(wday) - 1;
} else {
switch (addr) {
case RTC_STAT_REGA: {
RtcRegA old_rega(stat_regA);
stat_regA = data;
// The "update in progress" bit is read only.
stat_regA.uip = old_rega;
if (!rega_dv_disabled(stat_regA) &&
stat_regA.dv != RTCA_DV_32768HZ) {
inform("RTC: Unimplemented divider configuration: %i\n",
stat_regA.dv);
panic_unsupported = true;
}
if (stat_regA.rs != RTCA_RS_1024HZ) {
inform("RTC: Unimplemented interrupt rate: %i\n",
stat_regA.rs);
panic_unsupported = true;
}
if (rega_dv_disabled(stat_regA)) {
// The divider is disabled, make sure that we don't
// schedule any ticks.
if (tickEvent.scheduled())
deschedule(tickEvent);
} else if (rega_dv_disabled(old_rega)) {
// According to the specification, the next tick
// happens after 0.5s when the divider chain goes
// from reset to active. So, we simply schedule the
// tick after 0.5s.
assert(!tickEvent.scheduled());
schedule(tickEvent, curTick() + sim_clock::as_int::s / 2);
}
} break;
case RTC_STAT_REGB:
stat_regB = data;
if (stat_regB.aie || stat_regB.uie) {
inform("RTC: Unimplemented interrupt configuration: %s %s\n",
stat_regB.aie ? "alarm" : "",
stat_regB.uie ? "update" : "");
panic_unsupported = true;
}
if (stat_regB.dm) {
inform("RTC: The binary interface is not fully implemented.\n");
panic_unsupported = true;
}
if (!stat_regB.format24h) {
inform("RTC: The 12h time format not supported.\n");
panic_unsupported = true;
}
if (stat_regB.dse) {
inform("RTC: Automatic daylight saving time not supported.\n");
panic_unsupported = true;
}
if (stat_regB.pie) {
if (!event.scheduled())
event.scheduleIntr();
} else {
if (event.scheduled())
deschedule(event);
}
break;
case RTC_STAT_REGC:
case RTC_STAT_REGD:
panic("RTC status registers C and D are not implemented.\n");
break;
}
}
if (panic_unsupported)
panic("Unimplemented RTC configuration!\n");
}
uint8_t
MC146818::readData(uint8_t addr)
{
if (addr < RTC_STAT_REGA)
return clock_data[addr];
else {
switch (addr) {
case RTC_STAT_REGA:
// Linux after v5.10 checks this multiple times so toggling
// leads to a deadlock on bootup.
stat_regA.uip = 0;
return stat_regA;
break;
case RTC_STAT_REGB:
return stat_regB;
break;
case RTC_STAT_REGC:
case RTC_STAT_REGD:
return 0x00;
break;
default:
panic("Shouldn't be here");
}
}
}
void
MC146818::tickClock()
{
assert(!rega_dv_disabled(stat_regA));
if (stat_regB.set)
return;
time_t calTime = mkutctime(&curTime);
calTime++;
setTime(*gmtime(&calTime));
}
void
MC146818::serialize(const std::string &base, CheckpointOut &cp) const
{
uint8_t regA_serial(stat_regA);
uint8_t regB_serial(stat_regB);
arrayParamOut(cp, base + ".clock_data", clock_data, sizeof(clock_data));
paramOut(cp, base + ".stat_regA", (uint8_t)regA_serial);
paramOut(cp, base + ".stat_regB", (uint8_t)regB_serial);
//
// save the timer tick and rtc clock tick values to correctly reschedule
// them during unserialize
//
Tick rtcTimerInterruptTickOffset = event.when() - curTick();
SERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
Tick rtcClockTickOffset = tickEvent.when() - curTick();
SERIALIZE_SCALAR(rtcClockTickOffset);
}
void
MC146818::unserialize(const std::string &base, CheckpointIn &cp)
{
uint8_t tmp8;
arrayParamIn(cp, base + ".clock_data", clock_data,
sizeof(clock_data));
paramIn(cp, base + ".stat_regA", tmp8);
stat_regA = tmp8;
paramIn(cp, base + ".stat_regB", tmp8);
stat_regB = tmp8;
//
// properly schedule the timer and rtc clock events
//
Tick rtcTimerInterruptTickOffset;
UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
event.offset = rtcTimerInterruptTickOffset;
Tick rtcClockTickOffset;
UNSERIALIZE_SCALAR(rtcClockTickOffset);
tickEvent.offset = rtcClockTickOffset;
}
MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
: parent(_parent), interval(i), offset(i)
{
DPRINTF(MC146818, "RTC Event Initilizing\n");
}
void
MC146818::RTCEvent::scheduleIntr()
{
parent->schedule(this, curTick() + interval);
}
void
MC146818::RTCEvent::process()
{
DPRINTF(MC146818, "RTC Timer Interrupt\n");
parent->schedule(this, curTick() + interval);
parent->handleEvent();
}
const char *
MC146818::RTCEvent::description() const
{
return "RTC interrupt";
}
void
MC146818::RTCTickEvent::process()
{
DPRINTF(MC146818, "RTC clock tick\n");
parent->schedule(this, curTick() + sim_clock::as_int::s);
parent->tickClock();
}
const char *
MC146818::RTCTickEvent::description() const
{
return "RTC clock tick";
}
} // namespace gem5