hw/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/timer.h"
  24 #include "sysbus.h"
  25 #include "i2c.h"
  26
  27 #ifndef EXYNOS4_I2C_DEBUG
  28 #define EXYNOS4_I2C_DEBUG                 0
  29 #endif
  30
  31 #define TYPE_EXYNOS4_I2C                  "exynos4210.i2c"
  32 #define EXYNOS4_I2C(obj)                  \
  33     OBJECT_CHECK(Exynos4210I2CState, (obj), TYPE_EXYNOS4_I2C)
  34
  35 /* Exynos4210 I2C memory map */
  36 #define EXYNOS4_I2C_MEM_SIZE              0x14
  37 #define I2CCON_ADDR                       0x00  /* control register */
  38 #define I2CSTAT_ADDR                      0x04  /* control/status register */
  39 #define I2CADD_ADDR                       0x08  /* address register */
  40 #define I2CDS_ADDR                        0x0c  /* data shift register */
  41 #define I2CLC_ADDR                        0x10  /* line control register */
  42
  43 #define I2CCON_ACK_GEN                    (1 << 7)
  44 #define I2CCON_INTRS_EN                   (1 << 5)
  45 #define I2CCON_INT_PEND                   (1 << 4)
  46
  47 #define EXYNOS4_I2C_MODE(reg)             (((reg) >> 6) & 3)
  48 #define I2C_IN_MASTER_MODE(reg)           (((reg) >> 6) & 2)
  49 #define I2CMODE_MASTER_Rx                 0x2
  50 #define I2CMODE_MASTER_Tx                 0x3
  51 #define I2CSTAT_LAST_BIT                  (1 << 0)
  52 #define I2CSTAT_OUTPUT_EN                 (1 << 4)
  53 #define I2CSTAT_START_BUSY                (1 << 5)
  54
  55
  56 #if EXYNOS4_I2C_DEBUG
  57 #define DPRINT(fmt, args...)              \
  58     do { fprintf(stderr, "QEMU I2C: "fmt, ## args); } while (0)
  59
  60 static const char *exynos4_i2c_get_regname(unsigned offset)
  61 {
  62     switch (offset) {
  63     case I2CCON_ADDR:
  64         return "I2CCON";
  65     case I2CSTAT_ADDR:
  66         return "I2CSTAT";
  67     case I2CADD_ADDR:
  68         return "I2CADD";
  69     case I2CDS_ADDR:
  70         return "I2CDS";
  71     case I2CLC_ADDR:
  72         return "I2CLC";
  73     default:
  74         return "[?]";
  75     }
  76 }
  77
  78 #else
  79 #define DPRINT(fmt, args...)              do { } while (0)
  80 #endif
  81
  82 typedef struct Exynos4210I2CState {
  83     SysBusDevice busdev;
  84     MemoryRegion iomem;
  85     i2c_bus *bus;
  86     qemu_irq irq;
  87
  88     uint8_t i2ccon;
  89     uint8_t i2cstat;
  90     uint8_t i2cadd;
  91     uint8_t i2cds;
  92     uint8_t i2clc;
  93     bool scl_free;
  94 } Exynos4210I2CState;
  95
  96 static inline void exynos4210_i2c_raise_interrupt(Exynos4210I2CState *s)
  97 {
  98     if (s->i2ccon & I2CCON_INTRS_EN) {
  99         s->i2ccon |= I2CCON_INT_PEND;
 100         qemu_irq_raise(s->irq);
 101     }
 102 }
 103
 104 static void exynos4210_i2c_data_receive(void *opaque)
 105 {
 106     Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
 107     int ret;
 108
 109     s->i2cstat &= ~I2CSTAT_LAST_BIT;
 110     s->scl_free = false;
 111     ret = i2c_recv(s->bus);
 112     if (ret < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
 113         s->i2cstat |= I2CSTAT_LAST_BIT;  /* Data is not acknowledged */
 114     } else {
 115         s->i2cds = ret;
 116     }
 117     exynos4210_i2c_raise_interrupt(s);
 118 }
 119
 120 static void exynos4210_i2c_data_send(void *opaque)
 121 {
 122     Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
 123
 124     s->i2cstat &= ~I2CSTAT_LAST_BIT;
 125     s->scl_free = false;
 126     if (i2c_send(s->bus, s->i2cds) < 0 && (s->i2ccon & I2CCON_ACK_GEN)) {
 127         s->i2cstat |= I2CSTAT_LAST_BIT;
 128     }
 129     exynos4210_i2c_raise_interrupt(s);
 130 }
 131
 132 static uint64_t exynos4210_i2c_read(void *opaque, hwaddr offset,
 133                                  unsigned size)
 134 {
 135     Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
 136     uint8_t value;
 137
 138     switch (offset) {
 139     case I2CCON_ADDR:
 140         value = s->i2ccon;
 141         break;
 142     case I2CSTAT_ADDR:
 143         value = s->i2cstat;
 144         break;
 145     case I2CADD_ADDR:
 146         value = s->i2cadd;
 147         break;
 148     case I2CDS_ADDR:
 149         value = s->i2cds;
 150         s->scl_free = true;
 151         if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx &&
 152                (s->i2cstat & I2CSTAT_START_BUSY) &&
 153                !(s->i2ccon & I2CCON_INT_PEND)) {
 154             exynos4210_i2c_data_receive(s);
 155         }
 156         break;
 157     case I2CLC_ADDR:
 158         value = s->i2clc;
 159         break;
 160     default:
 161         value = 0;
 162         DPRINT("ERROR: Bad read offset 0x%x\n", (unsigned int)offset);
 163         break;
 164     }
 165
 166     DPRINT("read %s [0x%02x] -> 0x%02x\n", exynos4_i2c_get_regname(offset),
 167             (unsigned int)offset, value);
 168     return value;
 169 }
 170
 171 static void exynos4210_i2c_write(void *opaque, hwaddr offset,
 172                               uint64_t value, unsigned size)
 173 {
 174     Exynos4210I2CState *s = (Exynos4210I2CState *)opaque;
 175     uint8_t v = value & 0xff;
 176
 177     DPRINT("write %s [0x%02x] <- 0x%02x\n", exynos4_i2c_get_regname(offset),
 178             (unsigned int)offset, v);
 179
 180     switch (offset) {
 181     case I2CCON_ADDR:
 182         s->i2ccon = (v & ~I2CCON_INT_PEND) | (s->i2ccon & I2CCON_INT_PEND);
 183         if ((s->i2ccon & I2CCON_INT_PEND) && !(v & I2CCON_INT_PEND)) {
 184             s->i2ccon &= ~I2CCON_INT_PEND;
 185             qemu_irq_lower(s->irq);
 186             if (!(s->i2ccon & I2CCON_INTRS_EN)) {
 187                 s->i2cstat &= ~I2CSTAT_START_BUSY;
 188             }
 189
 190             if (s->i2cstat & I2CSTAT_START_BUSY) {
 191                 if (s->scl_free) {
 192                     if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx) {
 193                         exynos4210_i2c_data_send(s);
 194                     } else if (EXYNOS4_I2C_MODE(s->i2cstat) ==
 195                             I2CMODE_MASTER_Rx) {
 196                         exynos4210_i2c_data_receive(s);
 197                     }
 198                 } else {
 199                     s->i2ccon |= I2CCON_INT_PEND;
 200                     qemu_irq_raise(s->irq);
 201                 }
 202             }
 203         }
 204         break;
 205     case I2CSTAT_ADDR:
 206         s->i2cstat =
 207                 (s->i2cstat & I2CSTAT_START_BUSY) | (v & ~I2CSTAT_START_BUSY);
 208
 209         if (!(s->i2cstat & I2CSTAT_OUTPUT_EN)) {
 210             s->i2cstat &= ~I2CSTAT_START_BUSY;
 211             s->scl_free = true;
 212             qemu_irq_lower(s->irq);
 213             break;
 214         }
 215
 216         /* Nothing to do if in i2c slave mode */
 217         if (!I2C_IN_MASTER_MODE(s->i2cstat)) {
 218             break;
 219         }
 220
 221         if (v & I2CSTAT_START_BUSY) {
 222             s->i2cstat &= ~I2CSTAT_LAST_BIT;
 223             s->i2cstat |= I2CSTAT_START_BUSY;    /* Line is busy */
 224             s->scl_free = false;
 225
 226             /* Generate start bit and send slave address */
 227             if (i2c_start_transfer(s->bus, s->i2cds >> 1, s->i2cds & 0x1) &&
 228                     (s->i2ccon & I2CCON_ACK_GEN)) {
 229                 s->i2cstat |= I2CSTAT_LAST_BIT;
 230             } else if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Rx) {
 231                 exynos4210_i2c_data_receive(s);
 232             }
 233             exynos4210_i2c_raise_interrupt(s);
 234         } else {
 235             i2c_end_transfer(s->bus);
 236             if (!(s->i2ccon & I2CCON_INT_PEND)) {
 237                 s->i2cstat &= ~I2CSTAT_START_BUSY;
 238             }
 239             s->scl_free = true;
 240         }
 241         break;
 242     case I2CADD_ADDR:
 243         if ((s->i2cstat & I2CSTAT_OUTPUT_EN) == 0) {
 244             s->i2cadd = v;
 245         }
 246         break;
 247     case I2CDS_ADDR:
 248         if (s->i2cstat & I2CSTAT_OUTPUT_EN) {
 249             s->i2cds = v;
 250             s->scl_free = true;
 251             if (EXYNOS4_I2C_MODE(s->i2cstat) == I2CMODE_MASTER_Tx &&
 252                     (s->i2cstat & I2CSTAT_START_BUSY) &&
 253                     !(s->i2ccon & I2CCON_INT_PEND)) {
 254                 exynos4210_i2c_data_send(s);
 255             }
 256         }
 257         break;
 258     case I2CLC_ADDR:
 259         s->i2clc = v;
 260         break;
 261     default:
 262         DPRINT("ERROR: Bad write offset 0x%x\n", (unsigned int)offset);
 263         break;
 264     }
 265 }
 266
 267 static const MemoryRegionOps exynos4210_i2c_ops = {
 268     .read = exynos4210_i2c_read,
 269     .write = exynos4210_i2c_write,
 270     .endianness = DEVICE_NATIVE_ENDIAN,
 271 };
 272
 273 static const VMStateDescription exynos4210_i2c_vmstate = {
 274     .name = TYPE_EXYNOS4_I2C,
 275     .version_id = 1,
 276     .minimum_version_id = 1,
 277     .fields = (VMStateField[]) {
 278         VMSTATE_UINT8(i2ccon, Exynos4210I2CState),
 279         VMSTATE_UINT8(i2cstat, Exynos4210I2CState),
 280         VMSTATE_UINT8(i2cds, Exynos4210I2CState),
 281         VMSTATE_UINT8(i2cadd, Exynos4210I2CState),
 282         VMSTATE_UINT8(i2clc, Exynos4210I2CState),
 283         VMSTATE_BOOL(scl_free, Exynos4210I2CState),
 284         VMSTATE_END_OF_LIST()
 285     }
 286 };
 287
 288 static void exynos4210_i2c_reset(DeviceState *d)
 289 {
 290     Exynos4210I2CState *s = EXYNOS4_I2C(d);
 291
 292     s->i2ccon  = 0x00;
 293     s->i2cstat = 0x00;
 294     s->i2cds   = 0xFF;
 295     s->i2clc   = 0x00;
 296     s->i2cadd  = 0xFF;
 297     s->scl_free = true;
 298 }
 299
 300 static int exynos4210_i2c_realize(SysBusDevice *dev)
 301 {
 302     Exynos4210I2CState *s = EXYNOS4_I2C(dev);
 303
 304     memory_region_init_io(&s->iomem, &exynos4210_i2c_ops, s, TYPE_EXYNOS4_I2C,
 305                           EXYNOS4_I2C_MEM_SIZE);
 306     sysbus_init_mmio(dev, &s->iomem);
 307     sysbus_init_irq(dev, &s->irq);
 308     s->bus = i2c_init_bus(&dev->qdev, "i2c");
 309     return 0;
 310 }
 311
 312 static void exynos4210_i2c_class_init(ObjectClass *klass, void *data)
 313 {
 314     DeviceClass *dc = DEVICE_CLASS(klass);
 315     SysBusDeviceClass *sbdc = SYS_BUS_DEVICE_CLASS(klass);
 316
 317     dc->vmsd = &exynos4210_i2c_vmstate;
 318     dc->reset = exynos4210_i2c_reset;
 319     sbdc->init = exynos4210_i2c_realize;
 320 }
 321
 322 static const TypeInfo exynos4210_i2c_type_info = {
 323     .name = TYPE_EXYNOS4_I2C,
 324     .parent = TYPE_SYS_BUS_DEVICE,
 325     .instance_size = sizeof(Exynos4210I2CState),
 326     .class_init = exynos4210_i2c_class_init,
 327 };
 328
 329 static void exynos4210_i2c_register_types(void)
 330 {
 331     type_register_static(&exynos4210_i2c_type_info);
 332 }
 333
 334 type_init(exynos4210_i2c_register_types)