mc146818.cc revision 8593:92ba80d63abc 
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
35#include <ctime>
36#include <string>
37
38#include "base/bitfield.hh"
39#include "base/time.hh"
40#include "base/trace.hh"
41#include "debug/MC146818.hh"
42#include "dev/mc146818.hh"
43#include "dev/rtcreg.h"
44
45using namespace std;
46
47static uint8_t
48bcdize(uint8_t val)
49{
50    uint8_t result;
51    result = val % 10;
52    result += (val / 10) << 4;
53    return result;
54}
55
56static uint8_t
57unbcdize(uint8_t val)
58{
59    uint8_t result;
60    result = val & 0xf;
61    result += (val >> 4) * 10;
62    return result;
63}
64
65void
66MC146818::setTime(const struct tm time)
67{
68    curTime = time;
69    year = time.tm_year;
70    // Unix is 0-11 for month, data seet says start at 1
71    mon = time.tm_mon + 1;
72    mday = time.tm_mday;
73    hour = time.tm_hour;
74    min = time.tm_min;
75    sec = time.tm_sec;
76
77    // Datasheet says 1 is sunday
78    wday = time.tm_wday + 1;
79
80    if (!(stat_regB & RTCB_BIN)) {
81        // The datasheet says that the year field can be either BCD or
82        // years since 1900.  Linux seems to be happy with years since
83        // 1900.
84        year = bcdize(year % 100);
85        mon = bcdize(mon);
86        mday = bcdize(mday);
87        hour = bcdize(hour);
88        min = bcdize(min);
89        sec = bcdize(sec);
90    }
91}
92
93MC146818::MC146818(EventManager *em, const string &n, const struct tm time,
94                   bool bcd, Tick frequency)
95    : EventManager(em), _name(n), event(this, frequency), tickEvent(this)
96{
97    memset(clock_data, 0, sizeof(clock_data));
98    stat_regA = RTCA_32768HZ | RTCA_1024HZ;
99    stat_regB = RTCB_PRDC_IE | RTCB_24HR;
100    if (!bcd)
101        stat_regB |= RTCB_BIN;
102
103    setTime(time);
104    DPRINTFN("Real-time clock set to %s", asctime(&time));
105}
106
107MC146818::~MC146818()
108{
109    deschedule(tickEvent);
110    deschedule(event);
111}
112
113void
114MC146818::writeData(const uint8_t addr, const uint8_t data)
115{
116    if (addr < RTC_STAT_REGA) {
117        clock_data[addr] = data;
118        curTime.tm_sec = unbcdize(sec);
119        curTime.tm_min = unbcdize(min);
120        curTime.tm_hour = unbcdize(hour);
121        curTime.tm_mday = unbcdize(mday);
122        curTime.tm_mon = unbcdize(mon) - 1;
123        curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950;
124        curTime.tm_wday = unbcdize(wday) - 1;
125    } else {
126        switch (addr) {
127          case RTC_STAT_REGA:
128            // The "update in progress" bit is read only.
129            if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
130                panic("Unimplemented RTC register A value write!\n");
131            replaceBits(stat_regA, data, 6, 0);
132            break;
133          case RTC_STAT_REGB:
134            if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != RTCB_24HR)
135                panic("Write to RTC reg B bits that are not implemented!\n");
136
137            if (data & RTCB_PRDC_IE) {
138                if (!event.scheduled())
139                    event.scheduleIntr();
140            } else {
141                if (event.scheduled())
142                    deschedule(event);
143            }
144            stat_regB = data;
145            break;
146          case RTC_STAT_REGC:
147          case RTC_STAT_REGD:
148            panic("RTC status registers C and D are not implemented.\n");
149            break;
150        }
151    }
152}
153
154uint8_t
155MC146818::readData(uint8_t addr)
156{
157    if (addr < RTC_STAT_REGA)
158        return clock_data[addr];
159    else {
160        switch (addr) {
161          case RTC_STAT_REGA:
162            // toggle UIP bit for linux
163            stat_regA ^= RTCA_UIP;
164            return stat_regA;
165            break;
166          case RTC_STAT_REGB:
167            return stat_regB;
168            break;
169          case RTC_STAT_REGC:
170          case RTC_STAT_REGD:
171            return 0x00;
172            break;
173          default:
174            panic("Shouldn't be here");
175        }
176    }
177}
178
179static time_t
180mkutctime(struct tm *time)
181{
182    time_t ret;
183    char *tz;
184
185    tz = getenv("TZ");
186    setenv("TZ", "", 1);
187    tzset();
188    ret = mktime(time);
189    if (tz)
190        setenv("TZ", tz, 1);
191    else
192        unsetenv("TZ");
193    tzset();
194    return ret;
195}
196
197void
198MC146818::tickClock()
199{
200    if (stat_regB & RTCB_NO_UPDT)
201        return;
202    time_t calTime = mkutctime(&curTime);
203    calTime++;
204    setTime(*gmtime(&calTime));
205}
206
207void
208MC146818::serialize(const string &base, ostream &os)
209{
210    arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
211    paramOut(os, base + ".stat_regA", stat_regA);
212    paramOut(os, base + ".stat_regB", stat_regB);
213
214    //
215    // save the timer tick and rtc clock tick values to correctly reschedule
216    // them during unserialize
217    //
218    Tick rtcTimerInterruptTickOffset = event.when() - curTick();
219    SERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
220    Tick rtcClockTickOffset = tickEvent.when() - curTick();
221    SERIALIZE_SCALAR(rtcClockTickOffset);
222}
223
224void
225MC146818::unserialize(const string &base, Checkpoint *cp,
226                      const string &section)
227{
228    arrayParamIn(cp, section, base + ".clock_data", clock_data,
229                 sizeof(clock_data));
230    paramIn(cp, section, base + ".stat_regA", stat_regA);
231    paramIn(cp, section, base + ".stat_regB", stat_regB);
232
233    //
234    // properly schedule the timer and rtc clock events
235    //
236    Tick rtcTimerInterruptTickOffset;
237    UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
238    reschedule(event, curTick() + rtcTimerInterruptTickOffset);
239    Tick rtcClockTickOffset;
240    UNSERIALIZE_SCALAR(rtcClockTickOffset);
241    reschedule(tickEvent, curTick() + rtcClockTickOffset);
242}
243
244MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
245    : parent(_parent), interval(i)
246{
247    DPRINTF(MC146818, "RTC Event Initilizing\n");
248    parent->schedule(this, curTick() + interval);
249}
250
251void
252MC146818::RTCEvent::scheduleIntr()
253{
254    parent->schedule(this, curTick() + interval);
255}
256
257void
258MC146818::RTCEvent::process()
259{
260    DPRINTF(MC146818, "RTC Timer Interrupt\n");
261    parent->schedule(this, curTick() + interval);
262    parent->handleEvent();
263}
264
265const char *
266MC146818::RTCEvent::description() const
267{
268    return "RTC interrupt";
269}
270
271void
272MC146818::RTCTickEvent::process()
273{
274    DPRINTF(MC146818, "RTC clock tick\n");
275    parent->schedule(this, curTick() + SimClock::Int::s);
276    parent->tickClock();
277}
278
279const char *
280MC146818::RTCTickEvent::description() const
281{
282    return "RTC clock tick";
283}
284