2 * QEMU MC146818 RTC emulation
4 * Copyright (c) 2003-2004 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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
25 #ifndef MC146818RTC_REGS_H
26 #define MC146818RTC_REGS_H
28 #include "qemu/timer.h"
33 #define RTC_SECONDS_ALARM 1
35 #define RTC_MINUTES_ALARM 3
37 #define RTC_HOURS_ALARM 5
38 #define RTC_ALARM_DONT_CARE 0xC0
40 #define RTC_DAY_OF_WEEK 6
41 #define RTC_DAY_OF_MONTH 7
50 /* PC cmos mappings */
51 #define RTC_CENTURY 0x32
52 #define RTC_IBM_PS2_CENTURY_BYTE 0x37
54 #define REG_A_UIP 0x80
56 #define REG_B_SET 0x80
57 #define REG_B_PIE 0x40
58 #define REG_B_AIE 0x20
59 #define REG_B_UIE 0x10
60 #define REG_B_SQWE 0x08
62 #define REG_B_24H 0x02
65 #define REG_C_IRQF 0x80
68 #define REG_C_MASK 0x70
70 static inline uint32_t periodic_period_to_clock(int period_code
)
76 if (period_code
<= 2) {
79 /* period in 32 Khz cycles */
80 return 1 << (period_code
- 1);
83 #define RTC_CLOCK_RATE 32768
85 static inline int64_t periodic_clock_to_ns(int64_t clocks
)
87 return muldiv64(clocks
, NANOSECONDS_PER_SECOND
, RTC_CLOCK_RATE
);