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 MC146818RTC_REGS_H
26#define MC146818RTC_REGS_H
27
28#include "qemu/timer.h"
29
30#define RTC_ISA_IRQ 8
31
32#define RTC_SECONDS 0
33#define RTC_SECONDS_ALARM 1
34#define RTC_MINUTES 2
35#define RTC_MINUTES_ALARM 3
36#define RTC_HOURS 4
37#define RTC_HOURS_ALARM 5
38#define RTC_ALARM_DONT_CARE 0xC0
39
40#define RTC_DAY_OF_WEEK 6
41#define RTC_DAY_OF_MONTH 7
42#define RTC_MONTH 8
43#define RTC_YEAR 9
44
45#define RTC_REG_A 10
46#define RTC_REG_B 11
47#define RTC_REG_C 12
48#define RTC_REG_D 13
49
50/* PC cmos mappings */
51#define RTC_CENTURY 0x32
52#define RTC_IBM_PS2_CENTURY_BYTE 0x37
53
54#define REG_A_UIP 0x80
55
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
61#define REG_B_DM 0x04
62#define REG_B_24H 0x02
63
64#define REG_C_UF 0x10
65#define REG_C_IRQF 0x80
66#define REG_C_PF 0x40
67#define REG_C_AF 0x20
68#define REG_C_MASK 0x70
69
70static inline uint32_t periodic_period_to_clock(int period_code)
71{
72 if (!period_code) {
73 return 0;
74 }
75
76 if (period_code <= 2) {
77 period_code += 7;
78 }
79 /* period in 32 Khz cycles */
80 return 1 << (period_code - 1);
81}
82
83#define RTC_CLOCK_RATE 32768
84
85static inline int64_t periodic_clock_to_ns(int64_t clocks)
86{
87 return muldiv64(clocks, NANOSECONDS_PER_SECOND, RTC_CLOCK_RATE);
88}
89
90#endif
91