mc146818.cc revision 6677:b741b3e7164b 
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}
109
110void
111MC146818::writeData(const uint8_t addr, const uint8_t data)
112{
113    if (addr < RTC_STAT_REGA) {
114        clock_data[addr] = data;
115        curTime.tm_sec = unbcdize(sec);
116        curTime.tm_min = unbcdize(min);
117        curTime.tm_hour = unbcdize(hour);
118        curTime.tm_mday = unbcdize(mday);
119        curTime.tm_mon = unbcdize(mon) - 1;
120        curTime.tm_year = ((unbcdize(year) + 50) % 100) + 1950;
121        curTime.tm_wday = unbcdize(wday) - 1;
122    } else {
123        switch (addr) {
124          case RTC_STAT_REGA:
125            // The "update in progress" bit is read only.
126            if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
127                panic("Unimplemented RTC register A value write!\n");
128            replaceBits(stat_regA, data, 6, 0);
129            break;
130          case RTC_STAT_REGB:
131            if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != RTCB_24HR)
132                panic("Write to RTC reg B bits that are not implemented!\n");
133
134            if (data & RTCB_PRDC_IE) {
135                if (!event.scheduled())
136                    event.scheduleIntr();
137            } else {
138                if (event.scheduled())
139                    deschedule(event);
140            }
141            stat_regB = data;
142            break;
143          case RTC_STAT_REGC:
144          case RTC_STAT_REGD:
145            panic("RTC status registers C and D are not implemented.\n");
146            break;
147        }
148    }
149}
150
151uint8_t
152MC146818::readData(uint8_t addr)
153{
154    if (addr < RTC_STAT_REGA)
155        return clock_data[addr];
156    else {
157        switch (addr) {
158          case RTC_STAT_REGA:
159            // toggle UIP bit for linux
160            stat_regA ^= RTCA_UIP;
161            return stat_regA;
162            break;
163          case RTC_STAT_REGB:
164            return stat_regB;
165            break;
166          case RTC_STAT_REGC:
167          case RTC_STAT_REGD:
168            return 0x00;
169            break;
170          default:
171            panic("Shouldn't be here");
172        }
173    }
174}
175
176static time_t
177mkutctime(struct tm *time)
178{
179    time_t ret;
180    char *tz;
181
182    tz = getenv("TZ");
183    setenv("TZ", "", 1);
184    tzset();
185    ret = mktime(time);
186    if (tz)
187        setenv("TZ", tz, 1);
188    else
189        unsetenv("TZ");
190    tzset();
191    return ret;
192}
193
194void
195MC146818::tickClock()
196{
197    if (stat_regB & RTCB_NO_UPDT)
198        return;
199    time_t calTime = mkutctime(&curTime);
200    calTime++;
201    setTime(*gmtime(&calTime));
202}
203
204void
205MC146818::serialize(const string &base, ostream &os)
206{
207    arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
208    paramOut(os, base + ".stat_regA", stat_regA);
209    paramOut(os, base + ".stat_regB", stat_regB);
210
211    //
212    // save the timer tick and rtc clock tick values to correctly reschedule
213    // them during unserialize
214    //
215    Tick rtcTimerInterruptTickOffset = event.when() - curTick;
216    SERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
217    Tick rtcClockTickOffset = event.when() - curTick;
218    SERIALIZE_SCALAR(rtcClockTickOffset);
219}
220
221void
222MC146818::unserialize(const string &base, Checkpoint *cp,
223                      const string &section)
224{
225    arrayParamIn(cp, section, base + ".clock_data", clock_data,
226                 sizeof(clock_data));
227    paramIn(cp, section, base + ".stat_regA", stat_regA);
228    paramIn(cp, section, base + ".stat_regB", stat_regB);
229
230    //
231    // properly schedule the timer and rtc clock events
232    //
233    Tick rtcTimerInterruptTickOffset;
234    UNSERIALIZE_SCALAR(rtcTimerInterruptTickOffset);
235    reschedule(event, curTick + rtcTimerInterruptTickOffset);
236    Tick rtcClockTickOffset;
237    UNSERIALIZE_SCALAR(rtcClockTickOffset);
238    reschedule(tickEvent, curTick + rtcClockTickOffset);
239}
240
241MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
242    : parent(_parent), interval(i)
243{
244    DPRINTF(MC146818, "RTC Event Initilizing\n");
245    parent->schedule(this, curTick + interval);
246}
247
248void
249MC146818::RTCEvent::scheduleIntr()
250{
251    parent->schedule(this, curTick + interval);
252}
253
254void
255MC146818::RTCEvent::process()
256{
257    DPRINTF(MC146818, "RTC Timer Interrupt\n");
258    parent->schedule(this, curTick + interval);
259    parent->handleEvent();
260}
261
262const char *
263MC146818::RTCEvent::description() const
264{
265    return "RTC interrupt";
266}
267
268void
269MC146818::RTCTickEvent::process()
270{
271    DPRINTF(MC146818, "RTC clock tick\n");
272    parent->schedule(this, curTick + Clock::Int::s);
273    parent->tickClock();
274}
275
276const char *
277MC146818::RTCTickEvent::description() const
278{
279    return "RTC clock tick";
280}
281