mc146818.cc revision 6617:6d3645f68654 
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
46MC146818::MC146818(EventManager *em, const string &n, const struct tm time,
47                   bool bcd, Tick frequency)
48    : EventManager(em), _name(n), event(this, frequency)
49{
50    memset(clock_data, 0, sizeof(clock_data));
51    stat_regA = RTCA_32768HZ | RTCA_1024HZ;
52    stat_regB = RTCB_PRDC_IE | RTCB_24HR;
53    if (!bcd)
54        stat_regB |= RTCB_BIN;
55
56    year = time.tm_year;
57
58    if (bcd) {
59        // The datasheet says that the year field can be either BCD or
60        // years since 1900.  Linux seems to be happy with years since
61        // 1900.
62        year = year % 100;
63        int tens = year / 10;
64        int ones = year % 10;
65        year = (tens << 4) + ones;
66    }
67
68    // Unix is 0-11 for month, data seet says start at 1
69    mon = time.tm_mon + 1;
70    mday = time.tm_mday;
71    hour = time.tm_hour;
72    min = time.tm_min;
73    sec = time.tm_sec;
74
75    // Datasheet says 1 is sunday
76    wday = time.tm_wday + 1;
77
78    DPRINTFN("Real-time clock set to %s", asctime(&time));
79}
80
81MC146818::~MC146818()
82{
83}
84
85void
86MC146818::writeData(const uint8_t addr, const uint8_t data)
87{
88    if (addr < RTC_STAT_REGA)
89        clock_data[addr] = data;
90    else {
91        switch (addr) {
92          case RTC_STAT_REGA:
93            // The "update in progress" bit is read only.
94            if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
95                panic("Unimplemented RTC register A value write!\n");
96            replaceBits(stat_regA, data, 6, 0);
97            break;
98          case RTC_STAT_REGB:
99            if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != RTCB_24HR)
100                panic("Write to RTC reg B bits that are not implemented!\n");
101
102            if (data & RTCB_PRDC_IE) {
103                if (!event.scheduled())
104                    event.scheduleIntr();
105            } else {
106                if (event.scheduled())
107                    deschedule(event);
108            }
109            stat_regB = data;
110            break;
111          case RTC_STAT_REGC:
112          case RTC_STAT_REGD:
113            panic("RTC status registers C and D are not implemented.\n");
114            break;
115        }
116    }
117}
118
119uint8_t
120MC146818::readData(uint8_t addr)
121{
122    if (addr < RTC_STAT_REGA)
123        return clock_data[addr];
124    else {
125        switch (addr) {
126          case RTC_STAT_REGA:
127            // toggle UIP bit for linux
128            stat_regA ^= RTCA_UIP;
129            return stat_regA;
130            break;
131          case RTC_STAT_REGB:
132            return stat_regB;
133            break;
134          case RTC_STAT_REGC:
135          case RTC_STAT_REGD:
136            return 0x00;
137            break;
138          default:
139            panic("Shouldn't be here");
140        }
141    }
142}
143
144void
145MC146818::serialize(const string &base, ostream &os)
146{
147    arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
148    paramOut(os, base + ".stat_regA", stat_regA);
149    paramOut(os, base + ".stat_regB", stat_regB);
150}
151
152void
153MC146818::unserialize(const string &base, Checkpoint *cp,
154                      const string &section)
155{
156    arrayParamIn(cp, section, base + ".clock_data", clock_data,
157                 sizeof(clock_data));
158    paramIn(cp, section, base + ".stat_regA", stat_regA);
159    paramIn(cp, section, base + ".stat_regB", stat_regB);
160
161    // We're not unserializing the event here, but we need to
162    // rescehedule the event since curTick was moved forward by the
163    // checkpoint
164    reschedule(event, curTick + event.interval);
165}
166
167MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
168    : parent(_parent), interval(i)
169{
170    DPRINTF(MC146818, "RTC Event Initilizing\n");
171    parent->schedule(this, curTick + interval);
172}
173
174void
175MC146818::RTCEvent::scheduleIntr()
176{
177    parent->schedule(this, curTick + interval);
178}
179
180void
181MC146818::RTCEvent::process()
182{
183    DPRINTF(MC146818, "RTC Timer Interrupt\n");
184    parent->schedule(this, curTick + interval);
185    parent->handleEvent();
186}
187
188const char *
189MC146818::RTCEvent::description() const
190{
191    return "RTC interrupt";
192}
193