xref: /openbmc/qemu/system/rtc.c (revision 9d49b1c9edf829e571093088ddff0b73db3110c6)
1  /*
2   * RTC configuration and clock read
3   *
4   * Copyright (c) 2003-2020 QEMU contributors
5   *
6   * Permission is hereby granted, free of charge, to any person obtaining a copy
7   * of this software and associated documentation files (the "Software"), to deal
8   * in the Software without restriction, including without limitation the rights
9   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10   * copies of the Software, and to permit persons to whom the Software is
11   * furnished to do so, subject to the following conditions:
12   *
13   * The above copyright notice and this permission notice shall be included in
14   * all copies or substantial portions of the Software.
15   *
16   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22   * THE SOFTWARE.
23   */
24  
25  #include "qemu/osdep.h"
26  #include "qemu/cutils.h"
27  #include "qapi/error.h"
28  #include "qemu/error-report.h"
29  #include "qemu/option.h"
30  #include "qemu/timer.h"
31  #include "qom/object.h"
32  #include "sysemu/replay.h"
33  #include "sysemu/sysemu.h"
34  #include "sysemu/rtc.h"
35  #include "hw/rtc/mc146818rtc.h"
36  
37  static enum {
38      RTC_BASE_UTC,
39      RTC_BASE_LOCALTIME,
40      RTC_BASE_DATETIME,
41  } rtc_base_type = RTC_BASE_UTC;
42  static time_t rtc_ref_start_datetime;
43  static int rtc_realtime_clock_offset; /* used only with QEMU_CLOCK_REALTIME */
44  static int rtc_host_datetime_offset = -1; /* valid & used only with
45                                               RTC_BASE_DATETIME */
46  QEMUClockType rtc_clock;
47  /***********************************************************/
48  /* RTC reference time/date access */
49  static time_t qemu_ref_timedate(QEMUClockType clock)
50  {
51      time_t value = qemu_clock_get_ms(clock) / 1000;
52      switch (clock) {
53      case QEMU_CLOCK_REALTIME:
54          value -= rtc_realtime_clock_offset;
55          /* fall through */
56      case QEMU_CLOCK_VIRTUAL:
57          value += rtc_ref_start_datetime;
58          break;
59      case QEMU_CLOCK_HOST:
60          if (rtc_base_type == RTC_BASE_DATETIME) {
61              value -= rtc_host_datetime_offset;
62          }
63          break;
64      default:
65          g_assert_not_reached();
66      }
67      return value;
68  }
69  
70  void qemu_get_timedate(struct tm *tm, time_t offset)
71  {
72      time_t ti = qemu_ref_timedate(rtc_clock);
73  
74      ti += offset;
75  
76      switch (rtc_base_type) {
77      case RTC_BASE_DATETIME:
78      case RTC_BASE_UTC:
79          gmtime_r(&ti, tm);
80          break;
81      case RTC_BASE_LOCALTIME:
82          localtime_r(&ti, tm);
83          break;
84      }
85  }
86  
87  time_t qemu_timedate_diff(struct tm *tm)
88  {
89      time_t seconds;
90  
91      switch (rtc_base_type) {
92      case RTC_BASE_DATETIME:
93      case RTC_BASE_UTC:
94          seconds = mktimegm(tm);
95          break;
96      case RTC_BASE_LOCALTIME:
97      {
98          struct tm tmp = *tm;
99          tmp.tm_isdst = -1; /* use timezone to figure it out */
100          seconds = mktime(&tmp);
101          break;
102      }
103      default:
104          abort();
105      }
106  
107      return seconds - qemu_ref_timedate(QEMU_CLOCK_HOST);
108  }
109  
110  static void configure_rtc_base_datetime(const char *startdate)
111  {
112      time_t rtc_start_datetime;
113      struct tm tm;
114  
115      if (sscanf(startdate, "%d-%d-%dT%d:%d:%d", &tm.tm_year, &tm.tm_mon,
116                 &tm.tm_mday, &tm.tm_hour, &tm.tm_min, &tm.tm_sec) == 6) {
117          /* OK */
118      } else if (sscanf(startdate, "%d-%d-%d",
119                        &tm.tm_year, &tm.tm_mon, &tm.tm_mday) == 3) {
120          tm.tm_hour = 0;
121          tm.tm_min = 0;
122          tm.tm_sec = 0;
123      } else {
124          goto date_fail;
125      }
126      tm.tm_year -= 1900;
127      tm.tm_mon--;
128      rtc_start_datetime = mktimegm(&tm);
129      if (rtc_start_datetime == -1) {
130      date_fail:
131          error_report("invalid datetime format");
132          error_printf("valid formats: "
133                       "'2006-06-17T16:01:21' or '2006-06-17'\n");
134          exit(1);
135      }
136      rtc_host_datetime_offset = rtc_ref_start_datetime - rtc_start_datetime;
137      rtc_ref_start_datetime = rtc_start_datetime;
138  }
139  
140  void configure_rtc(QemuOpts *opts)
141  {
142      const char *value;
143  
144      /* Set defaults */
145      rtc_clock = QEMU_CLOCK_HOST;
146      rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
147      rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
148  
149      value = qemu_opt_get(opts, "base");
150      if (value) {
151          if (!strcmp(value, "utc")) {
152              rtc_base_type = RTC_BASE_UTC;
153          } else if (!strcmp(value, "localtime")) {
154              rtc_base_type = RTC_BASE_LOCALTIME;
155              replay_add_blocker("-rtc base=localtime");
156          } else {
157              rtc_base_type = RTC_BASE_DATETIME;
158              configure_rtc_base_datetime(value);
159          }
160      }
161      value = qemu_opt_get(opts, "clock");
162      if (value) {
163          if (!strcmp(value, "host")) {
164              rtc_clock = QEMU_CLOCK_HOST;
165          } else if (!strcmp(value, "rt")) {
166              rtc_clock = QEMU_CLOCK_REALTIME;
167          } else if (!strcmp(value, "vm")) {
168              rtc_clock = QEMU_CLOCK_VIRTUAL;
169          } else {
170              error_report("invalid option value '%s'", value);
171              exit(1);
172          }
173      }
174      value = qemu_opt_get(opts, "driftfix");
175      if (value) {
176          if (!strcmp(value, "slew")) {
177              object_register_sugar_prop(TYPE_MC146818_RTC,
178                                         "lost_tick_policy",
179                                         "slew",
180                                         false);
181              if (!object_class_by_name(TYPE_MC146818_RTC)) {
182                  warn_report("driftfix 'slew' is not available with this machine");
183              }
184          } else if (!strcmp(value, "none")) {
185              /* discard is default */
186          } else {
187              error_report("invalid option value '%s'", value);
188              exit(1);
189          }
190      }
191  }
192