hw/ssi/imx_spi.c

   1 /*
   2  * IMX SPI Controller
   3  *
   4  * Copyright (c) 2016 Jean-Christophe Dubois <jcd@tribudubois.net>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include "qemu/osdep.h"
  12 #include "hw/ssi/imx_spi.h"
  13 #include "sysemu/sysemu.h"
  14 #include "qemu/log.h"
  15
  16 #ifndef DEBUG_IMX_SPI
  17 #define DEBUG_IMX_SPI 0
  18 #endif
  19
  20 #define DPRINTF(fmt, args...) \
  21     do { \
  22         if (DEBUG_IMX_SPI) { \
  23             fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SPI, \
  24                                              __func__, ##args); \
  25         } \
  26     } while (0)
  27
  28 static const char *imx_spi_reg_name(uint32_t reg)
  29 {
  30     static char unknown[20];
  31
  32     switch (reg) {
  33     case ECSPI_RXDATA:
  34         return  "ECSPI_RXDATA";
  35     case ECSPI_TXDATA:
  36         return  "ECSPI_TXDATA";
  37     case ECSPI_CONREG:
  38         return  "ECSPI_CONREG";
  39     case ECSPI_CONFIGREG:
  40         return  "ECSPI_CONFIGREG";
  41     case ECSPI_INTREG:
  42         return  "ECSPI_INTREG";
  43     case ECSPI_DMAREG:
  44         return  "ECSPI_DMAREG";
  45     case ECSPI_STATREG:
  46         return  "ECSPI_STATREG";
  47     case ECSPI_PERIODREG:
  48         return  "ECSPI_PERIODREG";
  49     case ECSPI_TESTREG:
  50         return  "ECSPI_TESTREG";
  51     case ECSPI_MSGDATA:
  52         return  "ECSPI_MSGDATA";
  53     default:
  54         sprintf(unknown, "%d ?", reg);
  55         return unknown;
  56     }
  57 }
  58
  59 static const VMStateDescription vmstate_imx_spi = {
  60     .name = TYPE_IMX_SPI,
  61     .version_id = 1,
  62     .minimum_version_id = 1,
  63     .fields = (VMStateField[]) {
  64         VMSTATE_FIFO32(tx_fifo, IMXSPIState),
  65         VMSTATE_FIFO32(rx_fifo, IMXSPIState),
  66         VMSTATE_INT16(burst_length, IMXSPIState),
  67         VMSTATE_UINT32_ARRAY(regs, IMXSPIState, ECSPI_MAX),
  68         VMSTATE_END_OF_LIST()
  69     },
  70 };
  71
  72 static void imx_spi_txfifo_reset(IMXSPIState *s)
  73 {
  74     fifo32_reset(&s->tx_fifo);
  75     s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
  76     s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
  77 }
  78
  79 static void imx_spi_rxfifo_reset(IMXSPIState *s)
  80 {
  81     fifo32_reset(&s->rx_fifo);
  82     s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
  83     s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
  84     s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RO;
  85 }
  86
  87 static void imx_spi_update_irq(IMXSPIState *s)
  88 {
  89     int level;
  90
  91     if (fifo32_is_empty(&s->rx_fifo)) {
  92         s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR;
  93     } else {
  94         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RR;
  95     }
  96
  97     if (fifo32_is_full(&s->rx_fifo)) {
  98         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RF;
  99     } else {
 100         s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF;
 101     }
 102
 103     if (fifo32_is_empty(&s->tx_fifo)) {
 104         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE;
 105     } else {
 106         s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TE;
 107     }
 108
 109     if (fifo32_is_full(&s->tx_fifo)) {
 110         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TF;
 111     } else {
 112         s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF;
 113     }
 114
 115     level = s->regs[ECSPI_STATREG] & s->regs[ECSPI_INTREG] ? 1 : 0;
 116
 117     qemu_set_irq(s->irq, level);
 118
 119     DPRINTF("IRQ level is %d\n", level);
 120 }
 121
 122 static uint8_t imx_spi_selected_channel(IMXSPIState *s)
 123 {
 124     return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_SELECT);
 125 }
 126
 127 static uint32_t imx_spi_burst_length(IMXSPIState *s)
 128 {
 129     return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1;
 130 }
 131
 132 static bool imx_spi_is_enabled(IMXSPIState *s)
 133 {
 134     return s->regs[ECSPI_CONREG] & ECSPI_CONREG_EN;
 135 }
 136
 137 static bool imx_spi_channel_is_master(IMXSPIState *s)
 138 {
 139     uint8_t mode = EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_MODE);
 140
 141     return (mode & (1 << imx_spi_selected_channel(s))) ? true : false;
 142 }
 143
 144 static bool imx_spi_is_multiple_master_burst(IMXSPIState *s)
 145 {
 146     uint8_t wave = EXTRACT(s->regs[ECSPI_CONFIGREG], ECSPI_CONFIGREG_SS_CTL);
 147
 148     return imx_spi_channel_is_master(s) &&
 149            !(s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC) &&
 150            ((wave & (1 << imx_spi_selected_channel(s))) ? true : false);
 151 }
 152
 153 static void imx_spi_flush_txfifo(IMXSPIState *s)
 154 {
 155     uint32_t tx;
 156     uint32_t rx;
 157
 158     DPRINTF("Begin: TX Fifo Size = %d, RX Fifo Size = %d\n",
 159             fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
 160
 161     while (!fifo32_is_empty(&s->tx_fifo)) {
 162         int tx_burst = 0;
 163         int index = 0;
 164
 165         if (s->burst_length <= 0) {
 166             s->burst_length = imx_spi_burst_length(s);
 167
 168             DPRINTF("Burst length = %d\n", s->burst_length);
 169
 170             if (imx_spi_is_multiple_master_burst(s)) {
 171                 s->regs[ECSPI_CONREG] |= ECSPI_CONREG_XCH;
 172             }
 173         }
 174
 175         tx = fifo32_pop(&s->tx_fifo);
 176
 177         DPRINTF("data tx:0x%08x\n", tx);
 178
 179         tx_burst = MIN(s->burst_length, 32);
 180
 181         rx = 0;
 182
 183         while (tx_burst) {
 184             uint8_t byte = tx & 0xff;
 185
 186             DPRINTF("writing 0x%02x\n", (uint32_t)byte);
 187
 188             /* We need to write one byte at a time */
 189             byte = ssi_transfer(s->bus, byte);
 190
 191             DPRINTF("0x%02x read\n", (uint32_t)byte);
 192
 193             tx = tx >> 8;
 194             rx |= (byte << (index * 8));
 195
 196             /* Remove 8 bits from the actual burst */
 197             tx_burst -= 8;
 198             s->burst_length -= 8;
 199             index++;
 200         }
 201
 202         DPRINTF("data rx:0x%08x\n", rx);
 203
 204         if (fifo32_is_full(&s->rx_fifo)) {
 205             s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RO;
 206         } else {
 207             fifo32_push(&s->rx_fifo, (uint8_t)rx);
 208         }
 209
 210         if (s->burst_length <= 0) {
 211             s->regs[ECSPI_CONREG] &= ~ECSPI_CONREG_XCH;
 212
 213             if (!imx_spi_is_multiple_master_burst(s)) {
 214                 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
 215                 break;
 216             }
 217         }
 218     }
 219
 220     if (fifo32_is_empty(&s->tx_fifo)) {
 221         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
 222     }
 223
 224     /* TODO: We should also use TDR and RDR bits */
 225
 226     DPRINTF("End: TX Fifo Size = %d, RX Fifo Size = %d\n",
 227             fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
 228 }
 229
 230 static void imx_spi_reset(DeviceState *dev)
 231 {
 232     IMXSPIState *s = IMX_SPI(dev);
 233
 234     DPRINTF("\n");
 235
 236     memset(s->regs, 0, sizeof(s->regs));
 237
 238     s->regs[ECSPI_STATREG] = 0x00000003;
 239
 240     imx_spi_rxfifo_reset(s);
 241     imx_spi_txfifo_reset(s);
 242
 243     imx_spi_update_irq(s);
 244
 245     s->burst_length = 0;
 246 }
 247
 248 static uint64_t imx_spi_read(void *opaque, hwaddr offset, unsigned size)
 249 {
 250     uint32_t value = 0;
 251     IMXSPIState *s = opaque;
 252     uint32_t index = offset >> 2;
 253
 254     if (index >=  ECSPI_MAX) {
 255         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
 256                       HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
 257         return 0;
 258     }
 259
 260     switch (index) {
 261     case ECSPI_RXDATA:
 262         if (!imx_spi_is_enabled(s)) {
 263             value = 0;
 264         } else if (fifo32_is_empty(&s->rx_fifo)) {
 265             /* value is undefined */
 266             value = 0xdeadbeef;
 267         } else {
 268             /* read from the RX FIFO */
 269             value = fifo32_pop(&s->rx_fifo);
 270         }
 271
 272         break;
 273     case ECSPI_TXDATA:
 274         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from TX FIFO\n",
 275                       TYPE_IMX_SPI, __func__);
 276
 277         /* Reading from TXDATA gives 0 */
 278
 279         break;
 280     case ECSPI_MSGDATA:
 281         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from MSG FIFO\n",
 282                       TYPE_IMX_SPI, __func__);
 283
 284         /* Reading from MSGDATA gives 0 */
 285
 286         break;
 287     default:
 288         value = s->regs[index];
 289         break;
 290     }
 291
 292     DPRINTF("reg[%s] => 0x%" PRIx32 "\n", imx_spi_reg_name(index), value);
 293
 294     imx_spi_update_irq(s);
 295
 296     return (uint64_t)value;
 297 }
 298
 299 static void imx_spi_write(void *opaque, hwaddr offset, uint64_t value,
 300                            unsigned size)
 301 {
 302     IMXSPIState *s = opaque;
 303     uint32_t index = offset >> 2;
 304     uint32_t change_mask;
 305
 306     if (index >=  ECSPI_MAX) {
 307         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
 308                       HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset);
 309         return;
 310     }
 311
 312     DPRINTF("reg[%s] <= 0x%" PRIx32 "\n", imx_spi_reg_name(index),
 313             (uint32_t)value);
 314
 315     change_mask = s->regs[index] ^ value;
 316
 317     switch (index) {
 318     case ECSPI_RXDATA:
 319         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to write to RX FIFO\n",
 320                       TYPE_IMX_SPI, __func__);
 321         break;
 322     case ECSPI_TXDATA:
 323         if (!imx_spi_is_enabled(s)) {
 324             /* Ignore writes if device is disabled */
 325             break;
 326         } else if (fifo32_is_full(&s->tx_fifo)) {
 327             /* Ignore writes if queue is full */
 328             break;
 329         }
 330
 331         fifo32_push(&s->tx_fifo, (uint32_t)value);
 332
 333         if (imx_spi_channel_is_master(s) &&
 334             (s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC)) {
 335             /*
 336              * Start emitting if current channel is master and SMC bit is
 337              * set.
 338              */
 339             imx_spi_flush_txfifo(s);
 340         }
 341
 342         break;
 343     case ECSPI_STATREG:
 344         /* the RO and TC bits are write-one-to-clear */
 345         value &= ECSPI_STATREG_RO | ECSPI_STATREG_TC;
 346         s->regs[ECSPI_STATREG] &= ~value;
 347
 348         break;
 349     case ECSPI_CONREG:
 350         s->regs[ECSPI_CONREG] = value;
 351
 352         if (!imx_spi_is_enabled(s)) {
 353             /* device is disabled, so this is a reset */
 354             imx_spi_reset(DEVICE(s));
 355             return;
 356         }
 357
 358         if (imx_spi_channel_is_master(s)) {
 359             int i;
 360
 361             /* We are in master mode */
 362
 363             for (i = 0; i < 4; i++) {
 364                 qemu_set_irq(s->cs_lines[i],
 365                              i == imx_spi_selected_channel(s) ? 0 : 1);
 366             }
 367
 368             if ((value & change_mask & ECSPI_CONREG_SMC) &&
 369                 !fifo32_is_empty(&s->tx_fifo)) {
 370                 /* SMC bit is set and TX FIFO has some slots filled in */
 371                 imx_spi_flush_txfifo(s);
 372             } else if ((value & change_mask & ECSPI_CONREG_XCH) &&
 373                 !(value & ECSPI_CONREG_SMC)) {
 374                 /* This is a request to start emitting */
 375                 imx_spi_flush_txfifo(s);
 376             }
 377         }
 378
 379         break;
 380     case ECSPI_MSGDATA:
 381         /* it is not clear from the spec what MSGDATA is for */
 382         /* Anyway it is not used by Linux driver */
 383         /* So for now we just ignore it */
 384         qemu_log_mask(LOG_UNIMP,
 385                       "[%s]%s: Trying to write to MSGDATA, ignoring\n",
 386                       TYPE_IMX_SPI, __func__);
 387         break;
 388     default:
 389         s->regs[index] = value;
 390
 391         break;
 392     }
 393
 394     imx_spi_update_irq(s);
 395 }
 396
 397 static const struct MemoryRegionOps imx_spi_ops = {
 398     .read = imx_spi_read,
 399     .write = imx_spi_write,
 400     .endianness = DEVICE_NATIVE_ENDIAN,
 401     .valid = {
 402         /*
 403          * Our device would not work correctly if the guest was doing
 404          * unaligned access. This might not be a limitation on the real
 405          * device but in practice there is no reason for a guest to access
 406          * this device unaligned.
 407          */
 408         .min_access_size = 4,
 409         .max_access_size = 4,
 410         .unaligned = false,
 411     },
 412 };
 413
 414 static void imx_spi_realize(DeviceState *dev, Error **errp)
 415 {
 416     IMXSPIState *s = IMX_SPI(dev);
 417     int i;
 418
 419     s->bus = ssi_create_bus(dev, "spi");
 420
 421     memory_region_init_io(&s->iomem, OBJECT(dev), &imx_spi_ops, s,
 422                           TYPE_IMX_SPI, 0x1000);
 423     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
 424     sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
 425
 426     ssi_auto_connect_slaves(dev, s->cs_lines, s->bus);
 427
 428     for (i = 0; i < 4; ++i) {
 429         sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->cs_lines[i]);
 430     }
 431
 432     s->burst_length = 0;
 433
 434     fifo32_create(&s->tx_fifo, ECSPI_FIFO_SIZE);
 435     fifo32_create(&s->rx_fifo, ECSPI_FIFO_SIZE);
 436 }
 437
 438 static void imx_spi_class_init(ObjectClass *klass, void *data)
 439 {
 440     DeviceClass *dc = DEVICE_CLASS(klass);
 441
 442     dc->realize = imx_spi_realize;
 443     dc->vmsd = &vmstate_imx_spi;
 444     dc->reset = imx_spi_reset;
 445     dc->desc = "i.MX SPI Controller";
 446 }
 447
 448 static const TypeInfo imx_spi_info = {
 449     .name          = TYPE_IMX_SPI,
 450     .parent        = TYPE_SYS_BUS_DEVICE,
 451     .instance_size = sizeof(IMXSPIState),
 452     .class_init    = imx_spi_class_init,
 453 };
 454
 455 static void imx_spi_register_types(void)
 456 {
 457     type_register_static(&imx_spi_info);
 458 }
 459
 460 type_init(imx_spi_register_types)