xref: /illumos-kvm-cmd/hw/ds1338.c (revision 68396ea9)
1 /*
2  * MAXIM DS1338 I2C RTC+NVRAM
3  *
4  * Copyright (c) 2009 CodeSourcery.
5  * Written by Paul Brook
6  *
7  * This code is licenced under the GNU GPL v2.
8  */
9 
10 #include "i2c.h"
11 
12 typedef struct {
13     i2c_slave i2c;
14     time_t offset;
15     struct tm now;
16     uint8_t nvram[56];
17     int ptr;
18     int addr_byte;
19 } DS1338State;
20 
ds1338_event(i2c_slave * i2c,enum i2c_event event)21 static void ds1338_event(i2c_slave *i2c, enum i2c_event event)
22 {
23     DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
24 
25     switch (event) {
26     case I2C_START_RECV:
27         qemu_get_timedate(&s->now, s->offset);
28         s->nvram[0] = to_bcd(s->now.tm_sec);
29         s->nvram[1] = to_bcd(s->now.tm_min);
30         if (s->nvram[2] & 0x40) {
31             s->nvram[2] = (to_bcd((s->now.tm_hour % 12)) + 1) | 0x40;
32             if (s->now.tm_hour >= 12) {
33                 s->nvram[2] |= 0x20;
34             }
35         } else {
36             s->nvram[2] = to_bcd(s->now.tm_hour);
37         }
38         s->nvram[3] = to_bcd(s->now.tm_wday) + 1;
39         s->nvram[4] = to_bcd(s->now.tm_mday);
40         s->nvram[5] = to_bcd(s->now.tm_mon) + 1;
41         s->nvram[6] = to_bcd(s->now.tm_year - 100);
42         break;
43     case I2C_START_SEND:
44         s->addr_byte = 1;
45         break;
46     default:
47         break;
48     }
49 }
50 
ds1338_recv(i2c_slave * i2c)51 static int ds1338_recv(i2c_slave *i2c)
52 {
53     DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
54     uint8_t res;
55 
56     res  = s->nvram[s->ptr];
57     s->ptr = (s->ptr + 1) & 0xff;
58     return res;
59 }
60 
ds1338_send(i2c_slave * i2c,uint8_t data)61 static int ds1338_send(i2c_slave *i2c, uint8_t data)
62 {
63     DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
64     if (s->addr_byte) {
65         s->ptr = data;
66         s->addr_byte = 0;
67         return 0;
68     }
69     s->nvram[s->ptr - 8] = data;
70     if (data < 8) {
71         qemu_get_timedate(&s->now, s->offset);
72         switch(data) {
73         case 0:
74             /* TODO: Implement CH (stop) bit.  */
75             s->now.tm_sec = from_bcd(data & 0x7f);
76             break;
77         case 1:
78             s->now.tm_min = from_bcd(data & 0x7f);
79             break;
80         case 2:
81             if (data & 0x40) {
82                 if (data & 0x20) {
83                     data = from_bcd(data & 0x4f) + 11;
84                 } else {
85                     data = from_bcd(data & 0x1f) - 1;
86                 }
87             } else {
88                 data = from_bcd(data);
89             }
90             s->now.tm_hour = data;
91             break;
92         case 3:
93             s->now.tm_wday = from_bcd(data & 7) - 1;
94             break;
95         case 4:
96             s->now.tm_mday = from_bcd(data & 0x3f);
97             break;
98         case 5:
99             s->now.tm_mon = from_bcd(data & 0x1f) - 1;
100         case 6:
101             s->now.tm_year = from_bcd(data) + 100;
102             break;
103         case 7:
104             /* Control register. Currently ignored.  */
105             break;
106         }
107         s->offset = qemu_timedate_diff(&s->now);
108     }
109     s->ptr = (s->ptr + 1) & 0xff;
110     return 0;
111 }
112 
ds1338_init(i2c_slave * i2c)113 static int ds1338_init(i2c_slave *i2c)
114 {
115     return 0;
116 }
117 
118 static I2CSlaveInfo ds1338_info = {
119     .qdev.name = "ds1338",
120     .qdev.size = sizeof(DS1338State),
121     .init = ds1338_init,
122     .event = ds1338_event,
123     .recv = ds1338_recv,
124     .send = ds1338_send,
125 };
126 
ds1338_register_devices(void)127 static void ds1338_register_devices(void)
128 {
129     i2c_register_slave(&ds1338_info);
130 }
131 
132 device_init(ds1338_register_devices)
133