xref: /openbmc/qemu/include/hw/rtc/mc146818rtc_regs.h (revision bcdb90640ae41128e0c2ae2ec8ebf5a832102097)
1 /*
2  * QEMU MC146818 RTC emulation
3  *
4  * Copyright (c) 2003-2004 Fabrice Bellard
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 #ifndef HW_RTC_MC146818RTC_REGS_H
26 #define HW_RTC_MC146818RTC_REGS_H
27 
28 #include "qemu/timer.h"
29 #include "qemu/host-utils.h"
30 
31 #define RTC_ISA_IRQ 8
32 
33 #define RTC_SECONDS             0
34 #define RTC_SECONDS_ALARM       1
35 #define RTC_MINUTES             2
36 #define RTC_MINUTES_ALARM       3
37 #define RTC_HOURS               4
38 #define RTC_HOURS_ALARM         5
39 #define RTC_ALARM_DONT_CARE    0xC0
40 
41 #define RTC_DAY_OF_WEEK         6
42 #define RTC_DAY_OF_MONTH        7
43 #define RTC_MONTH               8
44 #define RTC_YEAR                9
45 
46 #define RTC_REG_A               10
47 #define RTC_REG_B               11
48 #define RTC_REG_C               12
49 #define RTC_REG_D               13
50 
51 /* PC cmos mappings */
52 #define RTC_CENTURY              0x32
53 #define RTC_IBM_PS2_CENTURY_BYTE 0x37
54 
55 #define REG_A_UIP 0x80
56 
57 #define REG_B_SET  0x80
58 #define REG_B_PIE  0x40
59 #define REG_B_AIE  0x20
60 #define REG_B_UIE  0x10
61 #define REG_B_SQWE 0x08
62 #define REG_B_DM   0x04
63 #define REG_B_24H  0x02
64 
65 #define REG_C_UF   0x10
66 #define REG_C_IRQF 0x80
67 #define REG_C_PF   0x40
68 #define REG_C_AF   0x20
69 #define REG_C_MASK 0x70
70 
71 static inline uint32_t periodic_period_to_clock(int period_code)
72 {
73     if (!period_code) {
74         return 0;
75    }
76 
77     if (period_code <= 2) {
78         period_code += 7;
79     }
80     /* period in 32 Khz cycles */
81    return 1 << (period_code - 1);
82 }
83 
84 #define RTC_CLOCK_RATE            32768
85 
86 static inline int64_t periodic_clock_to_ns(int64_t clocks)
87 {
88     return muldiv64(clocks, NANOSECONDS_PER_SECOND, RTC_CLOCK_RATE);
89 }
90 
91 #endif
92