1 /*
2 * i.MX I2C Bus Serial Interface Emulation
3 *
4 * Copyright (C) 2013 Jean-Christophe Dubois. <jcd@tribudubois.net>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "hw/i2c/imx_i2c.h"
23 #include "hw/irq.h"
24 #include "migration/vmstate.h"
25 #include "hw/i2c/i2c.h"
26 #include "qemu/log.h"
27 #include "qemu/module.h"
28
29 #ifndef DEBUG_IMX_I2C
30 #define DEBUG_IMX_I2C 0
31 #endif
32
33 #define DPRINTF(fmt, args...) \
34 do { \
35 if (DEBUG_IMX_I2C) { \
36 fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_I2C, \
37 __func__, ##args); \
38 } \
39 } while (0)
40
imx_i2c_get_regname(unsigned offset)41 static const char *imx_i2c_get_regname(unsigned offset)
42 {
43 switch (offset) {
44 case IADR_ADDR:
45 return "IADR";
46 case IFDR_ADDR:
47 return "IFDR";
48 case I2CR_ADDR:
49 return "I2CR";
50 case I2SR_ADDR:
51 return "I2SR";
52 case I2DR_ADDR:
53 return "I2DR";
54 default:
55 return "[?]";
56 }
57 }
58
imx_i2c_is_enabled(IMXI2CState * s)59 static inline bool imx_i2c_is_enabled(IMXI2CState *s)
60 {
61 return s->i2cr & I2CR_IEN;
62 }
63
imx_i2c_interrupt_is_enabled(IMXI2CState * s)64 static inline bool imx_i2c_interrupt_is_enabled(IMXI2CState *s)
65 {
66 return s->i2cr & I2CR_IIEN;
67 }
68
imx_i2c_is_master(IMXI2CState * s)69 static inline bool imx_i2c_is_master(IMXI2CState *s)
70 {
71 return s->i2cr & I2CR_MSTA;
72 }
73
imx_i2c_reset(DeviceState * dev)74 static void imx_i2c_reset(DeviceState *dev)
75 {
76 IMXI2CState *s = IMX_I2C(dev);
77
78 if (s->address != ADDR_RESET) {
79 i2c_end_transfer(s->bus);
80 }
81
82 s->address = ADDR_RESET;
83 s->iadr = IADR_RESET;
84 s->ifdr = IFDR_RESET;
85 s->i2cr = I2CR_RESET;
86 s->i2sr = I2SR_RESET;
87 s->i2dr_read = I2DR_RESET;
88 s->i2dr_write = I2DR_RESET;
89 }
90
imx_i2c_raise_interrupt(IMXI2CState * s)91 static inline void imx_i2c_raise_interrupt(IMXI2CState *s)
92 {
93 /*
94 * raise an interrupt if the device is enabled and it is configured
95 * to generate some interrupts.
96 */
97 if (imx_i2c_is_enabled(s) && imx_i2c_interrupt_is_enabled(s)) {
98 s->i2sr |= I2SR_IIF;
99 qemu_irq_raise(s->irq);
100 }
101 }
102
imx_i2c_read(void * opaque,hwaddr offset,unsigned size)103 static uint64_t imx_i2c_read(void *opaque, hwaddr offset,
104 unsigned size)
105 {
106 uint16_t value;
107 IMXI2CState *s = IMX_I2C(opaque);
108
109 switch (offset) {
110 case IADR_ADDR:
111 value = s->iadr;
112 break;
113 case IFDR_ADDR:
114 value = s->ifdr;
115 break;
116 case I2CR_ADDR:
117 value = s->i2cr;
118 break;
119 case I2SR_ADDR:
120 value = s->i2sr;
121 break;
122 case I2DR_ADDR:
123 value = s->i2dr_read;
124
125 if (imx_i2c_is_master(s)) {
126 uint8_t ret = 0xff;
127
128 if (s->address == ADDR_RESET) {
129 /* something is wrong as the address is not set */
130 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read "
131 "without specifying the slave address\n",
132 TYPE_IMX_I2C, __func__);
133 } else if (s->i2cr & I2CR_MTX) {
134 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read "
135 "but MTX is set\n", TYPE_IMX_I2C, __func__);
136 } else {
137 /* get the next byte */
138 ret = i2c_recv(s->bus);
139 imx_i2c_raise_interrupt(s);
140 }
141
142 s->i2dr_read = ret;
143 } else {
144 qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n",
145 TYPE_IMX_I2C, __func__);
146 }
147 break;
148 default:
149 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
150 HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset);
151 value = 0;
152 break;
153 }
154
155 DPRINTF("read %s [0x%" HWADDR_PRIx "] -> 0x%02x\n",
156 imx_i2c_get_regname(offset), offset, value);
157
158 return (uint64_t)value;
159 }
160
imx_i2c_write(void * opaque,hwaddr offset,uint64_t value,unsigned size)161 static void imx_i2c_write(void *opaque, hwaddr offset,
162 uint64_t value, unsigned size)
163 {
164 IMXI2CState *s = IMX_I2C(opaque);
165
166 DPRINTF("write %s [0x%" HWADDR_PRIx "] <- 0x%02x\n",
167 imx_i2c_get_regname(offset), offset, (int)value);
168
169 value &= 0xff;
170
171 switch (offset) {
172 case IADR_ADDR:
173 s->iadr = value & IADR_MASK;
174 /* i2c_slave_set_address(s->bus, (uint8_t)s->iadr); */
175 break;
176 case IFDR_ADDR:
177 s->ifdr = value & IFDR_MASK;
178 break;
179 case I2CR_ADDR:
180 if (imx_i2c_is_enabled(s) && ((value & I2CR_IEN) == 0)) {
181 /* This is a soft reset. IADR is preserved during soft resets */
182 uint16_t iadr = s->iadr;
183 imx_i2c_reset(DEVICE(s));
184 s->iadr = iadr;
185 } else { /* normal write */
186 s->i2cr = value & I2CR_MASK;
187
188 if (imx_i2c_is_master(s)) {
189 /* set the bus to busy */
190 s->i2sr |= I2SR_IBB;
191 } else { /* slave mode */
192 /* bus is not busy anymore */
193 s->i2sr &= ~I2SR_IBB;
194
195 /*
196 * if we unset the master mode then it ends the ongoing
197 * transfer if any
198 */
199 if (s->address != ADDR_RESET) {
200 i2c_end_transfer(s->bus);
201 s->address = ADDR_RESET;
202 }
203 }
204
205 if (s->i2cr & I2CR_RSTA) { /* Restart */
206 /* if this is a restart then it ends the ongoing transfer */
207 if (s->address != ADDR_RESET) {
208 i2c_end_transfer(s->bus);
209 s->address = ADDR_RESET;
210 s->i2cr &= ~I2CR_RSTA;
211 }
212 }
213 }
214 break;
215 case I2SR_ADDR:
216 /*
217 * if the user writes 0 to IIF then lower the interrupt and
218 * reset the bit
219 */
220 if ((s->i2sr & I2SR_IIF) && !(value & I2SR_IIF)) {
221 s->i2sr &= ~I2SR_IIF;
222 qemu_irq_lower(s->irq);
223 }
224
225 /*
226 * if the user writes 0 to IAL, reset the bit
227 */
228 if ((s->i2sr & I2SR_IAL) && !(value & I2SR_IAL)) {
229 s->i2sr &= ~I2SR_IAL;
230 }
231
232 break;
233 case I2DR_ADDR:
234 /* if the device is not enabled, nothing to do */
235 if (!imx_i2c_is_enabled(s)) {
236 break;
237 }
238
239 s->i2dr_write = value & I2DR_MASK;
240
241 if (imx_i2c_is_master(s)) {
242 /* If this is the first write cycle then it is the slave addr */
243 if (s->address == ADDR_RESET) {
244 if (i2c_start_transfer(s->bus, extract32(s->i2dr_write, 1, 7),
245 extract32(s->i2dr_write, 0, 1))) {
246 /* if non zero is returned, the address is not valid */
247 s->i2sr |= I2SR_RXAK;
248 } else {
249 s->address = s->i2dr_write;
250 s->i2sr &= ~I2SR_RXAK;
251 imx_i2c_raise_interrupt(s);
252 }
253 } else { /* This is a normal data write */
254 if (i2c_send(s->bus, s->i2dr_write)) {
255 /* if the target return non zero then end the transfer */
256 s->i2sr |= I2SR_RXAK;
257 s->address = ADDR_RESET;
258 i2c_end_transfer(s->bus);
259 } else {
260 s->i2sr &= ~I2SR_RXAK;
261 imx_i2c_raise_interrupt(s);
262 }
263 }
264 } else {
265 qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n",
266 TYPE_IMX_I2C, __func__);
267 }
268 break;
269 default:
270 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad address at offset 0x%"
271 HWADDR_PRIx "\n", TYPE_IMX_I2C, __func__, offset);
272 break;
273 }
274 }
275
276 static const MemoryRegionOps imx_i2c_ops = {
277 .read = imx_i2c_read,
278 .write = imx_i2c_write,
279 .valid.min_access_size = 1,
280 .valid.max_access_size = 2,
281 .endianness = DEVICE_NATIVE_ENDIAN,
282 };
283
284 static const VMStateDescription imx_i2c_vmstate = {
285 .name = TYPE_IMX_I2C,
286 .version_id = 1,
287 .minimum_version_id = 1,
288 .fields = (const VMStateField[]) {
289 VMSTATE_UINT16(address, IMXI2CState),
290 VMSTATE_UINT16(iadr, IMXI2CState),
291 VMSTATE_UINT16(ifdr, IMXI2CState),
292 VMSTATE_UINT16(i2cr, IMXI2CState),
293 VMSTATE_UINT16(i2sr, IMXI2CState),
294 VMSTATE_UINT16(i2dr_read, IMXI2CState),
295 VMSTATE_UINT16(i2dr_write, IMXI2CState),
296 VMSTATE_END_OF_LIST()
297 }
298 };
299
imx_i2c_realize(DeviceState * dev,Error ** errp)300 static void imx_i2c_realize(DeviceState *dev, Error **errp)
301 {
302 IMXI2CState *s = IMX_I2C(dev);
303
304 memory_region_init_io(&s->iomem, OBJECT(s), &imx_i2c_ops, s, TYPE_IMX_I2C,
305 IMX_I2C_MEM_SIZE);
306 sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
307 sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
308 s->bus = i2c_init_bus(dev, NULL);
309 }
310
imx_i2c_class_init(ObjectClass * klass,void * data)311 static void imx_i2c_class_init(ObjectClass *klass, void *data)
312 {
313 DeviceClass *dc = DEVICE_CLASS(klass);
314
315 dc->vmsd = &imx_i2c_vmstate;
316 device_class_set_legacy_reset(dc, imx_i2c_reset);
317 dc->realize = imx_i2c_realize;
318 dc->desc = "i.MX I2C Controller";
319 }
320
321 static const TypeInfo imx_i2c_type_info = {
322 .name = TYPE_IMX_I2C,
323 .parent = TYPE_SYS_BUS_DEVICE,
324 .instance_size = sizeof(IMXI2CState),
325 .class_init = imx_i2c_class_init,
326 };
327
imx_i2c_register_types(void)328 static void imx_i2c_register_types(void)
329 {
330 type_register_static(&imx_i2c_type_info);
331 }
332
333 type_init(imx_i2c_register_types)
334