2 * MAXIM DS1338 I2C RTC+NVRAM
4 * Copyright (c) 2009 CodeSourcery.
5 * Written by Paul Brook
7 * This code is licensed under the GNU GPL v2.
9 * Contributions after 2012-01-13 are licensed under the terms of the
10 * GNU GPL, version 2 or (at your option) any later version.
13 #include "qemu/osdep.h"
14 #include "qemu-common.h"
15 #include "hw/i2c/i2c.h"
17 #include "qemu/module.h"
19 /* Size of NVRAM including both the user-accessible area and the
20 * secondary register area.
24 /* Flags definitions */
25 #define SECONDS_CH 0x80
30 #define TYPE_DS1338 "ds1338"
31 #define DS1338(obj) OBJECT_CHECK(DS1338State, (obj), TYPE_DS1338)
33 typedef struct DS1338State
{
38 uint8_t nvram
[NVRAM_SIZE
];
43 static const VMStateDescription vmstate_ds1338
= {
46 .minimum_version_id
= 1,
47 .fields
= (VMStateField
[]) {
48 VMSTATE_I2C_SLAVE(parent_obj
, DS1338State
),
49 VMSTATE_INT64(offset
, DS1338State
),
50 VMSTATE_UINT8_V(wday_offset
, DS1338State
, 2),
51 VMSTATE_UINT8_ARRAY(nvram
, DS1338State
, NVRAM_SIZE
),
52 VMSTATE_INT32(ptr
, DS1338State
),
53 VMSTATE_BOOL(addr_byte
, DS1338State
),
58 static void capture_current_time(DS1338State
*s
)
60 /* Capture the current time into the secondary registers
61 * which will be actually read by the data transfer operation.
64 qemu_get_timedate(&now
, s
->offset
);
65 s
->nvram
[0] = to_bcd(now
.tm_sec
);
66 s
->nvram
[1] = to_bcd(now
.tm_min
);
67 if (s
->nvram
[2] & HOURS_12
) {
68 int tmp
= now
.tm_hour
;
73 s
->nvram
[2] = HOURS_12
| to_bcd(tmp
);
75 s
->nvram
[2] = HOURS_12
| HOURS_PM
| to_bcd(tmp
- 12);
78 s
->nvram
[2] = to_bcd(now
.tm_hour
);
80 s
->nvram
[3] = (now
.tm_wday
+ s
->wday_offset
) % 7 + 1;
81 s
->nvram
[4] = to_bcd(now
.tm_mday
);
82 s
->nvram
[5] = to_bcd(now
.tm_mon
+ 1);
83 s
->nvram
[6] = to_bcd(now
.tm_year
- 100);
86 static void inc_regptr(DS1338State
*s
)
88 /* The register pointer wraps around after 0x3F; wraparound
89 * causes the current time/date to be retransferred into
90 * the secondary registers.
92 s
->ptr
= (s
->ptr
+ 1) & (NVRAM_SIZE
- 1);
94 capture_current_time(s
);
98 static int ds1338_event(I2CSlave
*i2c
, enum i2c_event event
)
100 DS1338State
*s
= DS1338(i2c
);
104 /* In h/w, capture happens on any START condition, not just a
105 * START_RECV, but there is no need to actually capture on
106 * START_SEND, because the guest can't get at that data
107 * without going through a START_RECV which would overwrite it.
109 capture_current_time(s
);
121 static uint8_t ds1338_recv(I2CSlave
*i2c
)
123 DS1338State
*s
= DS1338(i2c
);
126 res
= s
->nvram
[s
->ptr
];
131 static int ds1338_send(I2CSlave
*i2c
, uint8_t data
)
133 DS1338State
*s
= DS1338(i2c
);
136 s
->ptr
= data
& (NVRAM_SIZE
- 1);
137 s
->addr_byte
= false;
143 qemu_get_timedate(&now
, s
->offset
);
146 /* TODO: Implement CH (stop) bit. */
147 now
.tm_sec
= from_bcd(data
& 0x7f);
150 now
.tm_min
= from_bcd(data
& 0x7f);
153 if (data
& HOURS_12
) {
154 int tmp
= from_bcd(data
& (HOURS_PM
- 1));
155 if (data
& HOURS_PM
) {
163 now
.tm_hour
= from_bcd(data
& (HOURS_12
- 1));
168 /* The day field is supposed to contain a value in
169 the range 1-7. Otherwise behavior is undefined.
171 int user_wday
= (data
& 7) - 1;
172 s
->wday_offset
= (user_wday
- now
.tm_wday
+ 7) % 7;
176 now
.tm_mday
= from_bcd(data
& 0x3f);
179 now
.tm_mon
= from_bcd(data
& 0x1f) - 1;
182 now
.tm_year
= from_bcd(data
) + 100;
185 s
->offset
= qemu_timedate_diff(&now
);
186 } else if (s
->ptr
== 7) {
187 /* Control register. */
189 /* Ensure bits 2, 3 and 6 will read back as zero. */
192 /* Attempting to write the OSF flag to logic 1 leaves the
194 data
= (data
& ~CTRL_OSF
) | (data
& s
->nvram
[s
->ptr
] & CTRL_OSF
);
196 s
->nvram
[s
->ptr
] = data
;
198 s
->nvram
[s
->ptr
] = data
;
204 static void ds1338_reset(DeviceState
*dev
)
206 DS1338State
*s
= DS1338(dev
);
208 /* The clock is running and synchronized with the host */
211 memset(s
->nvram
, 0, NVRAM_SIZE
);
213 s
->addr_byte
= false;
216 static void ds1338_class_init(ObjectClass
*klass
, void *data
)
218 DeviceClass
*dc
= DEVICE_CLASS(klass
);
219 I2CSlaveClass
*k
= I2C_SLAVE_CLASS(klass
);
221 k
->event
= ds1338_event
;
222 k
->recv
= ds1338_recv
;
223 k
->send
= ds1338_send
;
224 dc
->reset
= ds1338_reset
;
225 dc
->vmsd
= &vmstate_ds1338
;
228 static const TypeInfo ds1338_info
= {
230 .parent
= TYPE_I2C_SLAVE
,
231 .instance_size
= sizeof(DS1338State
),
232 .class_init
= ds1338_class_init
,
235 static void ds1338_register_types(void)
237 type_register_static(&ds1338_info
);
240 type_init(ds1338_register_types
)