tests/tcg: Do not require FE_* exception bits
[qemu.git] / hw / rtc / ds1338.c
1 /*
2 * MAXIM DS1338 I2C RTC+NVRAM
3 *
4 * Copyright (c) 2009 CodeSourcery.
5 * Written by Paul Brook
6 *
7 * This code is licensed under the GNU GPL v2.
8 *
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.
11 */
12
13 #include "qemu/osdep.h"
14 #include "qemu-common.h"
15 #include "hw/i2c/i2c.h"
16 #include "migration/vmstate.h"
17 #include "qemu/bcd.h"
18 #include "qemu/module.h"
19
20 /* Size of NVRAM including both the user-accessible area and the
21 * secondary register area.
22 */
23 #define NVRAM_SIZE 64
24
25 /* Flags definitions */
26 #define SECONDS_CH 0x80
27 #define HOURS_12 0x40
28 #define HOURS_PM 0x20
29 #define CTRL_OSF 0x20
30
31 #define TYPE_DS1338 "ds1338"
32 #define DS1338(obj) OBJECT_CHECK(DS1338State, (obj), TYPE_DS1338)
33
34 typedef struct DS1338State {
35 I2CSlave parent_obj;
36
37 int64_t offset;
38 uint8_t wday_offset;
39 uint8_t nvram[NVRAM_SIZE];
40 int32_t ptr;
41 bool addr_byte;
42 } DS1338State;
43
44 static const VMStateDescription vmstate_ds1338 = {
45 .name = "ds1338",
46 .version_id = 2,
47 .minimum_version_id = 1,
48 .fields = (VMStateField[]) {
49 VMSTATE_I2C_SLAVE(parent_obj, DS1338State),
50 VMSTATE_INT64(offset, DS1338State),
51 VMSTATE_UINT8_V(wday_offset, DS1338State, 2),
52 VMSTATE_UINT8_ARRAY(nvram, DS1338State, NVRAM_SIZE),
53 VMSTATE_INT32(ptr, DS1338State),
54 VMSTATE_BOOL(addr_byte, DS1338State),
55 VMSTATE_END_OF_LIST()
56 }
57 };
58
59 static void capture_current_time(DS1338State *s)
60 {
61 /* Capture the current time into the secondary registers
62 * which will be actually read by the data transfer operation.
63 */
64 struct tm now;
65 qemu_get_timedate(&now, s->offset);
66 s->nvram[0] = to_bcd(now.tm_sec);
67 s->nvram[1] = to_bcd(now.tm_min);
68 if (s->nvram[2] & HOURS_12) {
69 int tmp = now.tm_hour;
70 if (tmp % 12 == 0) {
71 tmp += 12;
72 }
73 if (tmp <= 12) {
74 s->nvram[2] = HOURS_12 | to_bcd(tmp);
75 } else {
76 s->nvram[2] = HOURS_12 | HOURS_PM | to_bcd(tmp - 12);
77 }
78 } else {
79 s->nvram[2] = to_bcd(now.tm_hour);
80 }
81 s->nvram[3] = (now.tm_wday + s->wday_offset) % 7 + 1;
82 s->nvram[4] = to_bcd(now.tm_mday);
83 s->nvram[5] = to_bcd(now.tm_mon + 1);
84 s->nvram[6] = to_bcd(now.tm_year - 100);
85 }
86
87 static void inc_regptr(DS1338State *s)
88 {
89 /* The register pointer wraps around after 0x3F; wraparound
90 * causes the current time/date to be retransferred into
91 * the secondary registers.
92 */
93 s->ptr = (s->ptr + 1) & (NVRAM_SIZE - 1);
94 if (!s->ptr) {
95 capture_current_time(s);
96 }
97 }
98
99 static int ds1338_event(I2CSlave *i2c, enum i2c_event event)
100 {
101 DS1338State *s = DS1338(i2c);
102
103 switch (event) {
104 case I2C_START_RECV:
105 /* In h/w, capture happens on any START condition, not just a
106 * START_RECV, but there is no need to actually capture on
107 * START_SEND, because the guest can't get at that data
108 * without going through a START_RECV which would overwrite it.
109 */
110 capture_current_time(s);
111 break;
112 case I2C_START_SEND:
113 s->addr_byte = true;
114 break;
115 default:
116 break;
117 }
118
119 return 0;
120 }
121
122 static uint8_t ds1338_recv(I2CSlave *i2c)
123 {
124 DS1338State *s = DS1338(i2c);
125 uint8_t res;
126
127 res = s->nvram[s->ptr];
128 inc_regptr(s);
129 return res;
130 }
131
132 static int ds1338_send(I2CSlave *i2c, uint8_t data)
133 {
134 DS1338State *s = DS1338(i2c);
135
136 if (s->addr_byte) {
137 s->ptr = data & (NVRAM_SIZE - 1);
138 s->addr_byte = false;
139 return 0;
140 }
141 if (s->ptr < 7) {
142 /* Time register. */
143 struct tm now;
144 qemu_get_timedate(&now, s->offset);
145 switch(s->ptr) {
146 case 0:
147 /* TODO: Implement CH (stop) bit. */
148 now.tm_sec = from_bcd(data & 0x7f);
149 break;
150 case 1:
151 now.tm_min = from_bcd(data & 0x7f);
152 break;
153 case 2:
154 if (data & HOURS_12) {
155 int tmp = from_bcd(data & (HOURS_PM - 1));
156 if (data & HOURS_PM) {
157 tmp += 12;
158 }
159 if (tmp % 12 == 0) {
160 tmp -= 12;
161 }
162 now.tm_hour = tmp;
163 } else {
164 now.tm_hour = from_bcd(data & (HOURS_12 - 1));
165 }
166 break;
167 case 3:
168 {
169 /* The day field is supposed to contain a value in
170 the range 1-7. Otherwise behavior is undefined.
171 */
172 int user_wday = (data & 7) - 1;
173 s->wday_offset = (user_wday - now.tm_wday + 7) % 7;
174 }
175 break;
176 case 4:
177 now.tm_mday = from_bcd(data & 0x3f);
178 break;
179 case 5:
180 now.tm_mon = from_bcd(data & 0x1f) - 1;
181 break;
182 case 6:
183 now.tm_year = from_bcd(data) + 100;
184 break;
185 }
186 s->offset = qemu_timedate_diff(&now);
187 } else if (s->ptr == 7) {
188 /* Control register. */
189
190 /* Ensure bits 2, 3 and 6 will read back as zero. */
191 data &= 0xB3;
192
193 /* Attempting to write the OSF flag to logic 1 leaves the
194 value unchanged. */
195 data = (data & ~CTRL_OSF) | (data & s->nvram[s->ptr] & CTRL_OSF);
196
197 s->nvram[s->ptr] = data;
198 } else {
199 s->nvram[s->ptr] = data;
200 }
201 inc_regptr(s);
202 return 0;
203 }
204
205 static void ds1338_reset(DeviceState *dev)
206 {
207 DS1338State *s = DS1338(dev);
208
209 /* The clock is running and synchronized with the host */
210 s->offset = 0;
211 s->wday_offset = 0;
212 memset(s->nvram, 0, NVRAM_SIZE);
213 s->ptr = 0;
214 s->addr_byte = false;
215 }
216
217 static void ds1338_class_init(ObjectClass *klass, void *data)
218 {
219 DeviceClass *dc = DEVICE_CLASS(klass);
220 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
221
222 k->event = ds1338_event;
223 k->recv = ds1338_recv;
224 k->send = ds1338_send;
225 dc->reset = ds1338_reset;
226 dc->vmsd = &vmstate_ds1338;
227 }
228
229 static const TypeInfo ds1338_info = {
230 .name = TYPE_DS1338,
231 .parent = TYPE_I2C_SLAVE,
232 .instance_size = sizeof(DS1338State),
233 .class_init = ds1338_class_init,
234 };
235
236 static void ds1338_register_types(void)
237 {
238 type_register_static(&ds1338_info);
239 }
240
241 type_init(ds1338_register_types)