a600f655605e97f192be7ac730575cfbfebc215d
[qemu.git] / hw / i2c / exynos4210_i2c.c
1 /*
2 * Exynos4210 I2C Bus Serial Interface Emulation
3 *
4 * Copyright (C) 2012 Samsung Electronics Co Ltd.
5 * Maksim Kozlov, <m.kozlov@samsung.com>
6 * Igor Mitsyanko, <i.mitsyanko@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 * for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, see <http://www.gnu.org/licenses/>.
20 *
21 */
22
23 #include "qemu/osdep.h"
24 #include "qemu/module.h"
25 #include "qemu/timer.h"
26 #include "hw/sysbus.h"
27 #include "migration/vmstate.h"
28 #include "hw/i2c/i2c.h"
29 #include "hw/irq.h"
30
31 #ifndef EXYNOS4_I2C_DEBUG
32 #define EXYNOS4_I2C_DEBUG 0
33 #endif
34
35 #define TYPE_EXYNOS4_I2C "exynos4210.i2c"
36 #define EXYNOS4_I2C(obj) \
37 OBJECT_CHECK(Exynos4210I2CState, (obj), TYPE_EXYNOS4_I2C)
38
39 /* Exynos4210 I2C memory map */
40 #define EXYNOS4_I2C_MEM_SIZE 0x14
41 #define I2CCON_ADDR 0x00 /* control register */
42 #define I2CSTAT_ADDR 0x04 /* control/status register */
43 #define I2CADD_ADDR 0x08 /* address register */
44 #define I2CDS_ADDR 0x0c /* data shift register */
45 #define I2CLC_ADDR 0x10 /* line control register */
46
47 #define I2CCON_ACK_GEN (1 << 7)
48 #define I2CCON_INTRS_EN (1 << 5)
49 #define I2CCON_INT_PEND (1 << 4)
50
51 #define EXYNOS4_I2C_MODE(reg) (((reg) >> 6) & 3)
52 #define I2C_IN_MASTER_MODE(reg) (((reg) >> 6) & 2)
53 #define I2CMODE_MASTER_Rx 0x2
54 #define I2CMODE_MASTER_Tx 0x3
55 #define I2CSTAT_LAST_BIT (1 << 0)
56 #define I2CSTAT_OUTPUT_EN (1 << 4)
57 #define I2CSTAT_START_BUSY (1 << 5)
58
59
60 #if EXYNOS4_I2C_DEBUG
61 #define DPRINT(fmt, args...) \
62 do { fprintf(stderr, "QEMU I2C: "fmt, ## args); } while (0)
63
64 static const char *exynos4_i2c_get_regname(unsigned offset)
65 {
66 switch (offset) {
67 case I2CCON_ADDR:
68 return "I2CCON";
69 case I2CSTAT_ADDR:
70 return "I2CSTAT";
71 case I2CADD_ADDR:
72 return "I2CADD";
73 case I2CDS_ADDR:
74 return "I2CDS";
75 case I2CLC_ADDR:
76 return "I2CLC";
77 default:
78 return "[?]";
79 }
80 }
81
82 #else
83 #define DPRINT(fmt, args...) do { } while (0)
84 #endif
85
86 typedef struct Exynos4210I2CState {
87 SysBusDevice parent_obj;
88
89 MemoryRegion iomem;
90 I2CBus *bus;
91 qemu_irq irq;
92
93 uint8_t i2ccon;
94 uint8_t i2cstat;
95 uint8_t i2cadd;
96 uint8_t i2cds;
97 uint8_t i2clc;
98 bool scl_free;
99 } Exynos4210I2CState;
100
101 static inline void exynos4210_i2c_raise_interrupt(Exynos4210I2CState *s)
102 {
103 if (s->i2ccon & I2CCON_INTRS_EN) {
104 s->i2ccon |= I2CCON_INT_PEND;
105 qemu_irq_raise(s->irq);
106 }
107 }
108
109 static void exynos4210_i2c_data_receive(void *opaque)
110 {
111 Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
112
113 s->i2cstat &= ~I2CSTAT_LAST_BIT;
114 s->scl_free = false;
115 s->i2cds = i2c_recv(s->bus);
116 exynos4210_i2c_raise_interrupt(s);
117 }
118
119 static void exynos4210_i2c_data_send(void *opaque)
120 {
121 Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
122
123 s->i2cstat &= ~I2CSTAT_LAST_BIT;
124 s->scl_free = false;
125 if (i2c_send(s->bus, s->i2cds) < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
126 s->i2cstat |= I2CSTAT_LAST_BIT;
127 }
128 exynos4210_i2c_raise_interrupt(s);
129 }
130
131 static uint64_t exynos4210_i2c_read(void *opaque, hwaddr offset,
132 unsigned size)
133 {
134 Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
135 uint8_t value;
136
137 switch (offset) {
138 case I2CCON_ADDR:
139 value = s->i2ccon;
140 break;
141 case I2CSTAT_ADDR:
142 value = s->i2cstat;
143 break;
144 case I2CADD_ADDR:
145 value = s->i2cadd;
146 break;
147 case I2CDS_ADDR:
148 value = s->i2cds;
149 s->scl_free = true;
150 if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx &&
151 (s->i2cstat & I2CSTAT_START_BUSY) &&
152 !(s->i2ccon & I2CCON_INT_PEND)) {
153 exynos4210_i2c_data_receive(s);
154 }
155 break;
156 case I2CLC_ADDR:
157 value = s->i2clc;
158 break;
159 default:
160 value = 0;
161 DPRINT("ERROR: Bad read offset 0x%x\n", (unsigned int)offset);
162 break;
163 }
164
165 DPRINT("read %s [0x%02x] -> 0x%02x\n", exynos4_i2c_get_regname(offset),
166 (unsigned int)offset, value);
167 return value;
168 }
169
170 static void exynos4210_i2c_write(void *opaque, hwaddr offset,
171 uint64_t value, unsigned size)
172 {
173 Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
174 uint8_t v = value & 0xff;
175
176 DPRINT("write %s [0x%02x] <- 0x%02x\n", exynos4_i2c_get_regname(offset),
177 (unsigned int)offset, v);
178
179 switch (offset) {
180 case I2CCON_ADDR:
181 s->i2ccon = (v & ~I2CCON_INT_PEND) | (s->i2ccon & I2CCON_INT_PEND);
182 if ((s->i2ccon & I2CCON_INT_PEND) && !(v & I2CCON_INT_PEND)) {
183 s->i2ccon &= ~I2CCON_INT_PEND;
184 qemu_irq_lower(s->irq);
185 if (!(s->i2ccon & I2CCON_INTRS_EN)) {
186 s->i2cstat &= ~I2CSTAT_START_BUSY;
187 }
188
189 if (s->i2cstat & I2CSTAT_START_BUSY) {
190 if (s->scl_free) {
191 if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx) {
192 exynos4210_i2c_data_send(s);
193 } else if (EXYNOS4_I2C_MODE(s->i2cstat) ==
194 I2CMODE_MASTER_Rx) {
195 exynos4210_i2c_data_receive(s);
196 }
197 } else {
198 s->i2ccon |= I2CCON_INT_PEND;
199 qemu_irq_raise(s->irq);
200 }
201 }
202 }
203 break;
204 case I2CSTAT_ADDR:
205 s->i2cstat =
206 (s->i2cstat & I2CSTAT_START_BUSY) | (v & ~I2CSTAT_START_BUSY);
207
208 if (!(s->i2cstat & I2CSTAT_OUTPUT_EN)) {
209 s->i2cstat &= ~I2CSTAT_START_BUSY;
210 s->scl_free = true;
211 qemu_irq_lower(s->irq);
212 break;
213 }
214
215 /* Nothing to do if in i2c slave mode */
216 if (!I2C_IN_MASTER_MODE(s->i2cstat)) {
217 break;
218 }
219
220 if (v & I2CSTAT_START_BUSY) {
221 s->i2cstat &= ~I2CSTAT_LAST_BIT;
222 s->i2cstat |= I2CSTAT_START_BUSY; /* Line is busy */
223 s->scl_free = false;
224
225 /* Generate start bit and send slave address */
226 if (i2c_start_transfer(s->bus, s->i2cds >> 1, s->i2cds & 0x1) &&
227 (s->i2ccon & I2CCON_ACK_GEN)) {
228 s->i2cstat |= I2CSTAT_LAST_BIT;
229 } else if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx) {
230 exynos4210_i2c_data_receive(s);
231 }
232 exynos4210_i2c_raise_interrupt(s);
233 } else {
234 i2c_end_transfer(s->bus);
235 if (!(s->i2ccon & I2CCON_INT_PEND)) {
236 s->i2cstat &= ~I2CSTAT_START_BUSY;
237 }
238 s->scl_free = true;
239 }
240 break;
241 case I2CADD_ADDR:
242 if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) {
243 s->i2cadd = v;
244 }
245 break;
246 case I2CDS_ADDR:
247 if (s->i2cstat & I2CSTAT_OUTPUT_EN) {
248 s->i2cds = v;
249 s->scl_free = true;
250 if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx &&
251 (s->i2cstat & I2CSTAT_START_BUSY) &&
252 !(s->i2ccon & I2CCON_INT_PEND)) {
253 exynos4210_i2c_data_send(s);
254 }
255 }
256 break;
257 case I2CLC_ADDR:
258 s->i2clc = v;
259 break;
260 default:
261 DPRINT("ERROR: Bad write offset 0x%x\n", (unsigned int)offset);
262 break;
263 }
264 }
265
266 static const MemoryRegionOps exynos4210_i2c_ops = {
267 .read = exynos4210_i2c_read,
268 .write = exynos4210_i2c_write,
269 .endianness = DEVICE_NATIVE_ENDIAN,
270 };
271
272 static const VMStateDescription exynos4210_i2c_vmstate = {
273 .name = "exynos4210.i2c",
274 .version_id = 1,
275 .minimum_version_id = 1,
276 .fields = (VMStateField[]) {
277 VMSTATE_UINT8(i2ccon, Exynos4210I2CState),
278 VMSTATE_UINT8(i2cstat, Exynos4210I2CState),
279 VMSTATE_UINT8(i2cds, Exynos4210I2CState),
280 VMSTATE_UINT8(i2cadd, Exynos4210I2CState),
281 VMSTATE_UINT8(i2clc, Exynos4210I2CState),
282 VMSTATE_BOOL(scl_free, Exynos4210I2CState),
283 VMSTATE_END_OF_LIST()
284 }
285 };
286
287 static void exynos4210_i2c_reset(DeviceState *d)
288 {
289 Exynos4210I2CState *s = EXYNOS4_I2C(d);
290
291 s->i2ccon = 0x00;
292 s->i2cstat = 0x00;
293 s->i2cds = 0xFF;
294 s->i2clc = 0x00;
295 s->i2cadd = 0xFF;
296 s->scl_free = true;
297 }
298
299 static void exynos4210_i2c_init(Object *obj)
300 {
301 DeviceState *dev = DEVICE(obj);
302 Exynos4210I2CState *s = EXYNOS4_I2C(obj);
303 SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
304
305 memory_region_init_io(&s->iomem, obj, &exynos4210_i2c_ops, s,
306 TYPE_EXYNOS4_I2C, EXYNOS4_I2C_MEM_SIZE);
307 sysbus_init_mmio(sbd, &s->iomem);
308 sysbus_init_irq(sbd, &s->irq);
309 s->bus = i2c_init_bus(dev, "i2c");
310 }
311
312 static void exynos4210_i2c_class_init(ObjectClass *klass, void *data)
313 {
314 DeviceClass *dc = DEVICE_CLASS(klass);
315
316 dc->vmsd = &exynos4210_i2c_vmstate;
317 dc->reset = exynos4210_i2c_reset;
318 }
319
320 static const TypeInfo exynos4210_i2c_type_info = {
321 .name = TYPE_EXYNOS4_I2C,
322 .parent = TYPE_SYS_BUS_DEVICE,
323 .instance_size = sizeof(Exynos4210I2CState),
324 .instance_init = exynos4210_i2c_init,
325 .class_init = exynos4210_i2c_class_init,
326 };
327
328 static void exynos4210_i2c_register_types(void)
329 {
330 type_register_static(&exynos4210_i2c_type_info);
331 }
332
333 type_init(exynos4210_i2c_register_types)