mc146818.cc revision 5813:624566640d7c 
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_BIN | RTCB_24HR;
53
54    year = time.tm_year;
55
56    if (bcd) {
57        // The datasheet says that the year field can be either BCD or
58        // years since 1900.  Linux seems to be happy with years since
59        // 1900.
60        year = year % 100;
61        int tens = year / 10;
62        int ones = year % 10;
63        year = (tens << 4) + ones;
64    }
65
66    // Unix is 0-11 for month, data seet says start at 1
67    mon = time.tm_mon + 1;
68    mday = time.tm_mday;
69    hour = time.tm_hour;
70    min = time.tm_min;
71    sec = time.tm_sec;
72
73    // Datasheet says 1 is sunday
74    wday = time.tm_wday + 1;
75
76    DPRINTFN("Real-time clock set to %s", asctime(&time));
77}
78
79MC146818::~MC146818()
80{
81}
82
83void
84MC146818::writeData(const uint8_t addr, const uint8_t data)
85{
86    if (addr < RTC_STAT_REGA)
87        clock_data[addr] = data;
88    else {
89        switch (addr) {
90          case RTC_STAT_REGA:
91            // The "update in progress" bit is read only.
92            if ((data & ~RTCA_UIP) != (RTCA_32768HZ | RTCA_1024HZ))
93                panic("Unimplemented RTC register A value write!\n");
94            replaceBits(stat_regA, data, 6, 0);
95            break;
96          case RTC_STAT_REGB:
97            if ((data & ~(RTCB_PRDC_IE | RTCB_SQWE)) != (RTCB_BIN | RTCB_24HR))
98                panic("Write to RTC reg B bits that are not implemented!\n");
99
100            if (data & RTCB_PRDC_IE) {
101                if (!event.scheduled())
102                    event.scheduleIntr();
103            } else {
104                if (event.scheduled())
105                    deschedule(event);
106            }
107            stat_regB = data;
108            break;
109          case RTC_STAT_REGC:
110          case RTC_STAT_REGD:
111            panic("RTC status registers C and D are not implemented.\n");
112            break;
113        }
114    }
115}
116
117uint8_t
118MC146818::readData(uint8_t addr)
119{
120    if (addr < RTC_STAT_REGA)
121        return clock_data[addr];
122    else {
123        switch (addr) {
124          case RTC_STAT_REGA:
125            // toggle UIP bit for linux
126            stat_regA ^= RTCA_UIP;
127            return stat_regA;
128            break;
129          case RTC_STAT_REGB:
130            return stat_regB;
131            break;
132          case RTC_STAT_REGC:
133          case RTC_STAT_REGD:
134            return 0x00;
135            break;
136          default:
137            panic("Shouldn't be here");
138        }
139    }
140}
141
142void
143MC146818::serialize(const string &base, ostream &os)
144{
145    arrayParamOut(os, base + ".clock_data", clock_data, sizeof(clock_data));
146    paramOut(os, base + ".stat_regA", stat_regA);
147    paramOut(os, base + ".stat_regB", stat_regB);
148}
149
150void
151MC146818::unserialize(const string &base, Checkpoint *cp,
152                      const string &section)
153{
154    arrayParamIn(cp, section, base + ".clock_data", clock_data,
155                 sizeof(clock_data));
156    paramIn(cp, section, base + ".stat_regA", stat_regA);
157    paramIn(cp, section, base + ".stat_regB", stat_regB);
158
159    // We're not unserializing the event here, but we need to
160    // rescehedule the event since curTick was moved forward by the
161    // checkpoint
162    reschedule(event, curTick + event.interval);
163}
164
165MC146818::RTCEvent::RTCEvent(MC146818 * _parent, Tick i)
166    : parent(_parent), interval(i)
167{
168    DPRINTF(MC146818, "RTC Event Initilizing\n");
169    parent->schedule(this, curTick + interval);
170}
171
172void
173MC146818::RTCEvent::scheduleIntr()
174{
175    parent->schedule(this, curTick + interval);
176}
177
178void
179MC146818::RTCEvent::process()
180{
181    DPRINTF(MC146818, "RTC Timer Interrupt\n");
182    parent->schedule(this, curTick + interval);
183    parent->handleEvent();
184}
185
186const char *
187MC146818::RTCEvent::description() const
188{
189    return "RTC interrupt";
190}
191