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 #include "qom/object.h" 31 32 #ifndef EXYNOS4_I2C_DEBUG 33 #define EXYNOS4_I2C_DEBUG 0 34 #endif 35 36 #define TYPE_EXYNOS4_I2C "exynos4210.i2c" 37 OBJECT_DECLARE_SIMPLE_TYPE(Exynos4210I2CState, 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 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 }; 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 = (const 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 device_class_set_legacy_reset(dc, 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) 334