@samitouri / QOSamiQemu
Code Commits Issues Pulls Sessions CI/CD
master
master
c 236 lines 5.84 KB
Raw
1 /*
2 * Ricoh RS5C372, R222x I2C RTC
3 *
4 * Copyright (c) 2025 Bernhard Beschow <shentey@gmail.com>
5 *
6 * Based on hw/rtc/ds1338.c
7 *
8 * SPDX-License-Identifier: GPL-2.0-or-later
9 */
10
11 #include "qemu/osdep.h"
12 #include "hw/i2c/i2c.h"
13 #include "hw/core/qdev-properties.h"
14 #include "hw/core/resettable.h"
15 #include "migration/vmstate.h"
16 #include "qemu/bcd.h"
17 #include "qom/object.h"
18 #include "system/rtc.h"
19 #include "trace.h"
20
21 #define NVRAM_SIZE 0x10
22
23 /* Flags definitions */
24 #define SECONDS_CH 0x80
25 #define HOURS_PM 0x20
26 #define CTRL2_24 0x20
27
28 #define TYPE_RS5C372 "rs5c372"
29 OBJECT_DECLARE_SIMPLE_TYPE(RS5C372State, RS5C372)
30
31 struct RS5C372State {
32 I2CSlave parent_obj;
33
34 int64_t offset;
35 uint8_t wday_offset;
36 uint8_t nvram[NVRAM_SIZE];
37 uint8_t ptr;
38 uint8_t tx_format;
39 bool addr_byte;
40 };
41
42 static void capture_current_time(RS5C372State *s)
43 {
44 /*
45 * Capture the current time into the secondary registers which will be
46 * actually read by the data transfer operation.
47 */
48 struct tm now;
49 qemu_get_timedate(&now, s->offset);
50 s->nvram[0] = to_bcd(now.tm_sec);
51 s->nvram[1] = to_bcd(now.tm_min);
52 if (s->nvram[0xf] & CTRL2_24) {
53 s->nvram[2] = to_bcd(now.tm_hour);
54 } else {
55 int tmp = now.tm_hour;
56 if (tmp % 12 == 0) {
57 tmp += 12;
58 }
59 if (tmp <= 12) {
60 s->nvram[2] = to_bcd(tmp);
61 } else {
62 s->nvram[2] = HOURS_PM | to_bcd(tmp - 12);
63 }
64 }
65 s->nvram[3] = (now.tm_wday + s->wday_offset) % 7 + 1;
66 s->nvram[4] = to_bcd(now.tm_mday);
67 s->nvram[5] = to_bcd(now.tm_mon + 1);
68 s->nvram[6] = to_bcd(now.tm_year - 100);
69 }
70
71 static void inc_regptr(RS5C372State *s)
72 {
73 s->ptr = (s->ptr + 1) & (NVRAM_SIZE - 1);
74 }
75
76 static int rs5c372_event(I2CSlave *i2c, enum i2c_event event)
77 {
78 RS5C372State *s = RS5C372(i2c);
79
80 switch (event) {
81 case I2C_START_RECV:
82 /*
83 * In h/w, capture happens on any START condition, not just a
84 * START_RECV, but there is no need to actually capture on
85 * START_SEND, because the guest can't get at that data
86 * without going through a START_RECV which would overwrite it.
87 */
88 capture_current_time(s);
89 s->ptr = 0xf;
90 break;
91 case I2C_START_SEND:
92 s->addr_byte = true;
93 break;
94 default:
95 break;
96 }
97
98 return 0;
99 }
100
101 static uint8_t rs5c372_recv(I2CSlave *i2c)
102 {
103 RS5C372State *s = RS5C372(i2c);
104 uint8_t res;
105
106 res = s->nvram[s->ptr];
107
108 trace_rs5c372_recv(s->ptr, res);
109
110 inc_regptr(s);
111 return res;
112 }
113
114 static int rs5c372_send(I2CSlave *i2c, uint8_t data)
115 {
116 RS5C372State *s = RS5C372(i2c);
117
118 if (s->addr_byte) {
119 s->ptr = data >> 4;
120 s->tx_format = data & 0xf;
121 s->addr_byte = false;
122 return 0;
123 }
124
125 trace_rs5c372_send(s->ptr, data);
126
127 if (s->ptr < 7) {
128 /* Time register. */
129 struct tm now;
130 qemu_get_timedate(&now, s->offset);
131 switch (s->ptr) {
132 case 0:
133 now.tm_sec = from_bcd(data & 0x7f);
134 break;
135 case 1:
136 now.tm_min = from_bcd(data & 0x7f);
137 break;
138 case 2:
139 if (s->nvram[0xf] & CTRL2_24) {
140 now.tm_hour = from_bcd(data & 0x3f);
141 } else {
142 int tmp = from_bcd(data & (HOURS_PM - 1));
143 if (data & HOURS_PM) {
144 tmp += 12;
145 }
146 if (tmp % 12 == 0) {
147 tmp -= 12;
148 }
149 now.tm_hour = tmp;
150 }
151 break;
152 case 3:
153 {
154 /*
155 * The day field is supposed to contain a value in the range
156 * 1-7. Otherwise behavior is undefined.
157 */
158 int user_wday = (data & 7) - 1;
159 s->wday_offset = (user_wday - now.tm_wday + 7) % 7;
160 }
161 break;
162 case 4:
163 now.tm_mday = from_bcd(data & 0x3f);
164 break;
165 case 5:
166 now.tm_mon = from_bcd(data & 0x1f) - 1;
167 break;
168 case 6:
169 now.tm_year = from_bcd(data) + 100;
170 break;
171 }
172 s->offset = qemu_timedate_diff(&now);
173 } else {
174 s->nvram[s->ptr] = data;
175 }
176 inc_regptr(s);
177 return 0;
178 }
179
180 static void rs5c372_reset_hold(Object *obj, ResetType type)
181 {
182 RS5C372State *s = RS5C372(obj);
183
184 /* The clock is running and synchronized with the host */
185 s->offset = 0;
186 s->wday_offset = 0;
187 memset(s->nvram, 0, NVRAM_SIZE);
188 s->ptr = 0;
189 s->addr_byte = false;
190 }
191
192 static const VMStateDescription rs5c372_vmstate = {
193 .name = "rs5c372",
194 .version_id = 1,
195 .minimum_version_id = 1,
196 .fields = (const VMStateField[]) {
197 VMSTATE_I2C_SLAVE(parent_obj, RS5C372State),
198 VMSTATE_INT64(offset, RS5C372State),
199 VMSTATE_UINT8_V(wday_offset, RS5C372State, 2),
200 VMSTATE_UINT8_ARRAY(nvram, RS5C372State, NVRAM_SIZE),
201 VMSTATE_UINT8(ptr, RS5C372State),
202 VMSTATE_UINT8(tx_format, RS5C372State),
203 VMSTATE_BOOL(addr_byte, RS5C372State),
204 VMSTATE_END_OF_LIST()
205 }
206 };
207
208 static void rs5c372_init(Object *obj)
209 {
210 qdev_prop_set_uint8(DEVICE(obj), "address", 0x32);
211 }
212
213 static void rs5c372_class_init(ObjectClass *klass, const void *data)
214 {
215 DeviceClass *dc = DEVICE_CLASS(klass);
216 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
217 ResettableClass *rc = RESETTABLE_CLASS(klass);
218
219 k->event = rs5c372_event;
220 k->recv = rs5c372_recv;
221 k->send = rs5c372_send;
222 dc->vmsd = &rs5c372_vmstate;
223 rc->phases.hold = rs5c372_reset_hold;
224 }
225
226 static const TypeInfo rs5c372_types[] = {
227 {
228 .name = TYPE_RS5C372,
229 .parent = TYPE_I2C_SLAVE,
230 .instance_size = sizeof(RS5C372State),
231 .instance_init = rs5c372_init,
232 .class_init = rs5c372_class_init,
233 },
234 };
235
236 DEFINE_TYPES(rs5c372_types)