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 #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 = (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)