mc146818.cc revision 7823:dac01f14f20f 
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Ali Saidi
29 *          Andrew Schultz
30 *          Miguel Serrano
31 */
32
33#include <sys/time.h>
34#include <time.h>
35
36#include <string>
37
38#include "base/bitfield.hh"
39#include "base/time.hh"
40#include "base/trace.hh"
41#include "dev/mc146818.hh"
42#include "dev/rtcreg.h"
43
44using namespace std;
45
46static uint8_t
47bcdize(uint8_t val)
48{
49    uint8_t result;
50    result = val % 10;
51    result += (val / 10) << 4;
52    return result;
53}
54
55static uint8_t
56unbcdize(uint8_t val)
57{
58    uint8_t result;
59    result = val & 0xf;
60    result += (val >> 4) * 10;
61    return result;
62}
63
64void
65MC146818::setTime(const struct tm time)
66{
67    curTime = time;
68    year = time.tm_year;
69    // Unix is 0-11 for month, data seet says start at 1
70    mon = time.tm_mon + 1;
71    mday = time.tm_mday;
72    hour = time.tm_hour;
73    min = time.tm_min;
74    sec = time.tm_sec;
75
76    // Datasheet says 1 is sunday
77    wday = time.tm_wday + 1;
78
79    if (!(stat_regB & RTCB_BIN)) {
80        // The datasheet says that the year field can be either BCD or
81        // years since 1900.  Linux seems to be happy with years since
82        // 1900.
83        year = bcdize(year % 100);
84        mon = bcdize(mon);
85        mday = bcdize(mday);
86        hour = bcdize(hour);
87        min = bcdize(min);
88        sec = bcdize(sec);
89    }
90}
91
92MC146818::MC146818(EventManager *em, const string &n, const struct tm time,
93                   bool bcd, Tick frequency)
94    : EventManager(em), _name(n), event(this, frequency), tickEvent(this)
95{
96    memset(clock_data, 0, sizeof(clock_data));
97    stat_regA = RTCA_32768HZ | RTCA_1024HZ;
98    stat_regB = RTCB_PRDC_IE | RTCB_24HR;
99    if (!bcd)
100        stat_regB |= RTCB_BIN;
101
102    setTime(time);
103    DPRINTFN("Real-time clock set to %s", asctime(&time));
104}
105
106MC146818::~MC146818()
107{
108    deschedule(tickEvent);
109    deschedule(event);
110}
111
112void
113MC146818::writeData(const uint8_t addr, const uint8_t data)
114{
115    if (addr < RTC_STAT_REGA) {
116        clock_data[addr] = data;
117        curTime.tm_sec = unbcdize(sec);
118        curTime.tm_min = unbcdize(min);
119        curTime.tm_hour = unbcdize(hour);
120        curTime.tm_mday = unbcdize(mday);
121        curTime.tm_mon = unbcdize(mon) - 1;
122        curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950;
123        curTime.tm_wday = unbcdize(wday) - 1;
124    } else {
125        switch (addr) {
126          case RTC_STAT_REGA:
127            // The "update in progress" bit is read only.
128            if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
129                panic("Unimplemented RTC register A value write!\n");
130            replaceBits(stat_regA, data, 6, 0);
131            break;
132          case RTC_STAT_REGB:
133            if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != RTCB_24HR)
134                panic("Write to RTC reg B bits that are not implemented!\n");
135
136            if (data & RTCB_PRDC_IE) {
137                if (!event.scheduled())
138                    event.scheduleIntr();
139            } else {
140                if (event.scheduled())
141                    deschedule(event);
142            }
143            stat_regB = data;
144            break;
145          case RTC_STAT_REGC:
146          case RTC_STAT_REGD:
147            panic("RTC status registers C and D are not implemented.\n");
148            break;
149        }
150    }
151}
152
153uint8_t
154MC146818::readData(uint8_t addr)
155{
156    if (addr < RTC_STAT_REGA)
157        return clock_data[addr];
158    else {
159        switch (addr) {
160          case RTC_STAT_REGA:
161            // toggle UIP bit for linux
162            stat_regA ^= RTCA_UIP;
163            return stat_regA;
164            break;
165          case RTC_STAT_REGB:
166            return stat_regB;
167            break;
168          case RTC_STAT_REGC:
169          case RTC_STAT_REGD:
170            return 0x00;
171            break;
172          default:
173            panic("Shouldn't be here");
174        }
175    }
176}
177
178static time_t
179mkutctime(struct tm *time)
180{
181    time_t ret;
182    char *tz;
183
184    tz = getenv("TZ");
185    setenv("TZ", "", 1);
186    tzset();
187    ret = mktime(time);
188    if (tz)
189        setenv("TZ", tz, 1);
190    else
191        unsetenv("TZ");
192    tzset();
193    return ret;
194}
195
196void
197MC146818::tickClock()
198{
199    if (stat_regB & RTCB_NO_UPDT)
200        return;
201    time_t calTime = mkutctime(&curTime);
202    calTime++;
203    setTime(*gmtime(&calTime));
204}
205
206void
207MC146818::serialize(const string &base, ostream &os)
208{
209    arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
210    paramOut(os, base + ".stat_regA", stat_regA);
211    paramOut(os, base + ".stat_regB", stat_regB);
212
213    //
214    // save the timer tick and rtc clock tick values to correctly reschedule
215    // them during unserialize
216    //
217    Tick rtcTimerInterruptTickOffset = event.when() - curTick();
218    SERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
219    Tick rtcClockTickOffset = event.when() - curTick();
220    SERIALIZE_SCALAR(rtcClockTickOffset);
221}
222
223void
224MC146818::unserialize(const string &base, Checkpoint *cp,
225                      const string &section)
226{
227    arrayParamIn(cp, section, base + ".clock_data", clock_data,
228                 sizeof(clock_data));
229    paramIn(cp, section, base + ".stat_regA", stat_regA);
230    paramIn(cp, section, base + ".stat_regB", stat_regB);
231
232    //
233    // properly schedule the timer and rtc clock events
234    //
235    Tick rtcTimerInterruptTickOffset;
236    UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
237    reschedule(event, curTick() + rtcTimerInterruptTickOffset);
238    Tick rtcClockTickOffset;
239    UNSERIALIZE_SCALAR(rtcClockTickOffset);
240    reschedule(tickEvent, curTick() + rtcClockTickOffset);
241}
242
243MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
244    : parent(_parent), interval(i)
245{
246    DPRINTF(MC146818, "RTC Event Initilizing\n");
247    parent->schedule(this, curTick() + interval);
248}
249
250void
251MC146818::RTCEvent::scheduleIntr()
252{
253    parent->schedule(this, curTick() + interval);
254}
255
256void
257MC146818::RTCEvent::process()
258{
259    DPRINTF(MC146818, "RTC Timer Interrupt\n");
260    parent->schedule(this, curTick() + interval);
261    parent->handleEvent();
262}
263
264const char *
265MC146818::RTCEvent::description() const
266{
267    return "RTC interrupt";
268}
269
270void
271MC146818::RTCTickEvent::process()
272{
273    DPRINTF(MC146818, "RTC clock tick\n");
274    parent->schedule(this, curTick() + SimClock::Int::s);
275    parent->tickClock();
276}
277
278const char *
279MC146818::RTCTickEvent::description() const
280{
281    return "RTC clock tick";
282}
283