summaryrefslogtreecommitdiff
path: root/hw/ds1338.c
blob: 6397f0aa6f94a86c0768182fa932fc8361ab7b63 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * MAXIM DS1338 I2C RTC+NVRAM
 *
 * Copyright (c) 2009 CodeSourcery.
 * Written by Paul Brook
 *
 * This code is licensed under the GNU GPL v2.
 *
 * Contributions after 2012-01-13 are licensed under the terms of the
 * GNU GPL, version 2 or (at your option) any later version.
 */

#include "i2c.h"

typedef struct {
    I2CSlave i2c;
    time_t offset;
    struct tm now;
    uint8_t nvram[56];
    int ptr;
    int addr_byte;
} DS1338State;

static void ds1338_event(I2CSlave *i2c, enum i2c_event event)
{
    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);

    switch (event) {
    case I2C_START_RECV:
        qemu_get_timedate(&s->now, s->offset);
        s->nvram[0] = to_bcd(s->now.tm_sec);
        s->nvram[1] = to_bcd(s->now.tm_min);
        if (s->nvram[2] & 0x40) {
            s->nvram[2] = (to_bcd((s->now.tm_hour % 12)) + 1) | 0x40;
            if (s->now.tm_hour >= 12) {
                s->nvram[2] |= 0x20;
            }
        } else {
            s->nvram[2] = to_bcd(s->now.tm_hour);
        }
        s->nvram[3] = to_bcd(s->now.tm_wday) + 1;
        s->nvram[4] = to_bcd(s->now.tm_mday);
        s->nvram[5] = to_bcd(s->now.tm_mon) + 1;
        s->nvram[6] = to_bcd(s->now.tm_year - 100);
        break;
    case I2C_START_SEND:
        s->addr_byte = 1;
        break;
    default:
        break;
    }
}

static int ds1338_recv(I2CSlave *i2c)
{
    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
    uint8_t res;

    res  = s->nvram[s->ptr];
    s->ptr = (s->ptr + 1) & 0xff;
    return res;
}

static int ds1338_send(I2CSlave *i2c, uint8_t data)
{
    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
    if (s->addr_byte) {
        s->ptr = data;
        s->addr_byte = 0;
        return 0;
    }
    s->nvram[s->ptr - 8] = data;
    if (data < 8) {
        qemu_get_timedate(&s->now, s->offset);
        switch(data) {
        case 0:
            /* TODO: Implement CH (stop) bit.  */
            s->now.tm_sec = from_bcd(data & 0x7f);
            break;
        case 1:
            s->now.tm_min = from_bcd(data & 0x7f);
            break;
        case 2:
            if (data & 0x40) {
                if (data & 0x20) {
                    data = from_bcd(data & 0x4f) + 11;
                } else {
                    data = from_bcd(data & 0x1f) - 1;
                }
            } else {
                data = from_bcd(data);
            }
            s->now.tm_hour = data;
            break;
        case 3:
            s->now.tm_wday = from_bcd(data & 7) - 1;
            break;
        case 4:
            s->now.tm_mday = from_bcd(data & 0x3f);
            break;
        case 5:
            s->now.tm_mon = from_bcd(data & 0x1f) - 1;
        case 6:
            s->now.tm_year = from_bcd(data) + 100;
            break;
        case 7:
            /* Control register. Currently ignored.  */
            break;
        }
        s->offset = qemu_timedate_diff(&s->now);
    }
    s->ptr = (s->ptr + 1) & 0xff;
    return 0;
}

static int ds1338_init(I2CSlave *i2c)
{
    return 0;
}

static void ds1338_class_init(ObjectClass *klass, void *data)
{
    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);

    k->init = ds1338_init;
    k->event = ds1338_event;
    k->recv = ds1338_recv;
    k->send = ds1338_send;
}

static TypeInfo ds1338_info = {
    .name          = "ds1338",
    .parent        = TYPE_I2C_SLAVE,
    .instance_size = sizeof(DS1338State),
    .class_init    = ds1338_class_init,
};

static void ds1338_register_types(void)
{
    type_register_static(&ds1338_info);
}

type_init(ds1338_register_types)