hw/ssi/mss-spi.c

   1 /*
   2  * Block model of SPI controller present in
   3  * Microsemi's SmartFusion2 and SmartFusion SoCs.
   4  *
   5  * Copyright (C) 2017 Subbaraya Sundeep <sundeep.lkml@gmail.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include "hw/irq.h"
  28 #include "hw/ssi/mss-spi.h"
  29 #include "migration/vmstate.h"
  30 #include "qemu/log.h"
  31 #include "qemu/module.h"
  32
  33 #ifndef MSS_SPI_ERR_DEBUG
  34 #define MSS_SPI_ERR_DEBUG   0
  35 #endif
  36
  37 #define DB_PRINT_L(lvl, fmt, args...) do { \
  38     if (MSS_SPI_ERR_DEBUG >= lvl) { \
  39         qemu_log("%s: " fmt "\n", __func__, ## args); \
  40     } \
  41 } while (0)
  42
  43 #define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
  44
  45 #define FIFO_CAPACITY         32
  46
  47 #define R_SPI_CONTROL         0
  48 #define R_SPI_DFSIZE          1
  49 #define R_SPI_STATUS          2
  50 #define R_SPI_INTCLR          3
  51 #define R_SPI_RX              4
  52 #define R_SPI_TX              5
  53 #define R_SPI_CLKGEN          6
  54 #define R_SPI_SS              7
  55 #define R_SPI_MIS             8
  56 #define R_SPI_RIS             9
  57
  58 #define S_TXDONE             (1 << 0)
  59 #define S_RXRDY              (1 << 1)
  60 #define S_RXCHOVRF           (1 << 2)
  61 #define S_RXFIFOFUL          (1 << 4)
  62 #define S_RXFIFOFULNXT       (1 << 5)
  63 #define S_RXFIFOEMP          (1 << 6)
  64 #define S_RXFIFOEMPNXT       (1 << 7)
  65 #define S_TXFIFOFUL          (1 << 8)
  66 #define S_TXFIFOFULNXT       (1 << 9)
  67 #define S_TXFIFOEMP          (1 << 10)
  68 #define S_TXFIFOEMPNXT       (1 << 11)
  69 #define S_FRAMESTART         (1 << 12)
  70 #define S_SSEL               (1 << 13)
  71 #define S_ACTIVE             (1 << 14)
  72
  73 #define C_ENABLE             (1 << 0)
  74 #define C_MODE               (1 << 1)
  75 #define C_INTRXDATA          (1 << 4)
  76 #define C_INTTXDATA          (1 << 5)
  77 #define C_INTRXOVRFLO        (1 << 6)
  78 #define C_SPS                (1 << 26)
  79 #define C_BIGFIFO            (1 << 29)
  80 #define C_RESET              (1 << 31)
  81
  82 #define FRAMESZ_MASK         0x3F
  83 #define FMCOUNT_MASK         0x00FFFF00
  84 #define FMCOUNT_SHIFT        8
  85 #define FRAMESZ_MAX          32
  86
  87 static void txfifo_reset(MSSSpiState *s)
  88 {
  89     fifo32_reset(&s->tx_fifo);
  90
  91     s->regs[R_SPI_STATUS] &= ~S_TXFIFOFUL;
  92     s->regs[R_SPI_STATUS] |= S_TXFIFOEMP;
  93 }
  94
  95 static void rxfifo_reset(MSSSpiState *s)
  96 {
  97     fifo32_reset(&s->rx_fifo);
  98
  99     s->regs[R_SPI_STATUS] &= ~S_RXFIFOFUL;
 100     s->regs[R_SPI_STATUS] |= S_RXFIFOEMP;
 101 }
 102
 103 static void set_fifodepth(MSSSpiState *s)
 104 {
 105     unsigned int size = s->regs[R_SPI_DFSIZE] & FRAMESZ_MASK;
 106
 107     if (size <= 8) {
 108         s->fifo_depth = 32;
 109     } else if (size <= 16) {
 110         s->fifo_depth = 16;
 111     } else {
 112         s->fifo_depth = 8;
 113     }
 114 }
 115
 116 static void update_mis(MSSSpiState *s)
 117 {
 118     uint32_t reg = s->regs[R_SPI_CONTROL];
 119     uint32_t tmp;
 120
 121     /*
 122      * form the Control register interrupt enable bits
 123      * same as RIS, MIS and Interrupt clear registers for simplicity
 124      */
 125     tmp = ((reg & C_INTRXOVRFLO) >> 4) | ((reg & C_INTRXDATA) >> 3) |
 126            ((reg & C_INTTXDATA) >> 5);
 127     s->regs[R_SPI_MIS] |= tmp & s->regs[R_SPI_RIS];
 128 }
 129
 130 static void spi_update_irq(MSSSpiState *s)
 131 {
 132     int irq;
 133
 134     update_mis(s);
 135     irq = !!(s->regs[R_SPI_MIS]);
 136
 137     qemu_set_irq(s->irq, irq);
 138 }
 139
 140 static void mss_spi_reset(DeviceState *d)
 141 {
 142     MSSSpiState *s = MSS_SPI(d);
 143
 144     memset(s->regs, 0, sizeof s->regs);
 145     s->regs[R_SPI_CONTROL] = 0x80000102;
 146     s->regs[R_SPI_DFSIZE] = 0x4;
 147     s->regs[R_SPI_STATUS] = S_SSEL | S_TXFIFOEMP | S_RXFIFOEMP;
 148     s->regs[R_SPI_CLKGEN] = 0x7;
 149     s->regs[R_SPI_RIS] = 0x0;
 150
 151     s->fifo_depth = 4;
 152     s->frame_count = 1;
 153     s->enabled = false;
 154
 155     rxfifo_reset(s);
 156     txfifo_reset(s);
 157 }
 158
 159 static uint64_t
 160 spi_read(void *opaque, hwaddr addr, unsigned int size)
 161 {
 162     MSSSpiState *s = opaque;
 163     uint32_t ret = 0;
 164
 165     addr >>= 2;
 166     switch (addr) {
 167     case R_SPI_RX:
 168         s->regs[R_SPI_STATUS] &= ~S_RXFIFOFUL;
 169         s->regs[R_SPI_STATUS] &= ~S_RXCHOVRF;
 170         if (fifo32_is_empty(&s->rx_fifo)) {
 171             qemu_log_mask(LOG_GUEST_ERROR,
 172                           "%s: Reading empty RX_FIFO\n",
 173                           __func__);
 174         } else {
 175             ret = fifo32_pop(&s->rx_fifo);
 176         }
 177         if (fifo32_is_empty(&s->rx_fifo)) {
 178             s->regs[R_SPI_STATUS] |= S_RXFIFOEMP;
 179         }
 180         break;
 181
 182     case R_SPI_MIS:
 183         update_mis(s);
 184         ret = s->regs[R_SPI_MIS];
 185         break;
 186
 187     default:
 188         if (addr < ARRAY_SIZE(s->regs)) {
 189             ret = s->regs[addr];
 190         } else {
 191             qemu_log_mask(LOG_GUEST_ERROR,
 192                          "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__,
 193                          addr * 4);
 194             return ret;
 195         }
 196         break;
 197     }
 198
 199     DB_PRINT("addr=0x%" HWADDR_PRIx " = 0x%" PRIx32, addr * 4, ret);
 200     spi_update_irq(s);
 201     return ret;
 202 }
 203
 204 static void assert_cs(MSSSpiState *s)
 205 {
 206     qemu_set_irq(s->cs_line, 0);
 207 }
 208
 209 static void deassert_cs(MSSSpiState *s)
 210 {
 211     qemu_set_irq(s->cs_line, 1);
 212 }
 213
 214 static void spi_flush_txfifo(MSSSpiState *s)
 215 {
 216     uint32_t tx;
 217     uint32_t rx;
 218     bool sps = !!(s->regs[R_SPI_CONTROL] & C_SPS);
 219
 220     /*
 221      * Chip Select(CS) is automatically controlled by this controller.
 222      * If SPS bit is set in Control register then CS is asserted
 223      * until all the frames set in frame count of Control register are
 224      * transferred. If SPS is not set then CS pulses between frames.
 225      * Note that Slave Select register specifies which of the CS line
 226      * has to be controlled automatically by controller. Bits SS[7:1] are for
 227      * masters in FPGA fabric since we model only Microcontroller subsystem
 228      * of Smartfusion2 we control only one CS(SS[0]) line.
 229      */
 230     while (!fifo32_is_empty(&s->tx_fifo) && s->frame_count) {
 231         assert_cs(s);
 232
 233         s->regs[R_SPI_STATUS] &= ~(S_TXDONE | S_RXRDY);
 234
 235         tx = fifo32_pop(&s->tx_fifo);
 236         DB_PRINT("data tx:0x%" PRIx32, tx);
 237         rx = ssi_transfer(s->spi, tx);
 238         DB_PRINT("data rx:0x%" PRIx32, rx);
 239
 240         if (fifo32_num_used(&s->rx_fifo) == s->fifo_depth) {
 241             s->regs[R_SPI_STATUS] |= S_RXCHOVRF;
 242             s->regs[R_SPI_RIS] |= S_RXCHOVRF;
 243         } else {
 244             fifo32_push(&s->rx_fifo, rx);
 245             s->regs[R_SPI_STATUS] &= ~S_RXFIFOEMP;
 246             if (fifo32_num_used(&s->rx_fifo) == (s->fifo_depth - 1)) {
 247                 s->regs[R_SPI_STATUS] |= S_RXFIFOFULNXT;
 248             } else if (fifo32_num_used(&s->rx_fifo) == s->fifo_depth) {
 249                 s->regs[R_SPI_STATUS] |= S_RXFIFOFUL;
 250             }
 251         }
 252         s->frame_count--;
 253         if (!sps) {
 254             deassert_cs(s);
 255         }
 256     }
 257
 258     if (!s->frame_count) {
 259         s->frame_count = (s->regs[R_SPI_CONTROL] & FMCOUNT_MASK) >>
 260                             FMCOUNT_SHIFT;
 261         deassert_cs(s);
 262         s->regs[R_SPI_RIS] |= S_TXDONE | S_RXRDY;
 263         s->regs[R_SPI_STATUS] |= S_TXDONE | S_RXRDY;
 264    }
 265 }
 266
 267 static void spi_write(void *opaque, hwaddr addr,
 268             uint64_t val64, unsigned int size)
 269 {
 270     MSSSpiState *s = opaque;
 271     uint32_t value = val64;
 272
 273     DB_PRINT("addr=0x%" HWADDR_PRIx " =0x%" PRIx32, addr, value);
 274     addr >>= 2;
 275
 276     switch (addr) {
 277     case R_SPI_TX:
 278         /* adding to already full FIFO */
 279         if (fifo32_num_used(&s->tx_fifo) == s->fifo_depth) {
 280             break;
 281         }
 282         s->regs[R_SPI_STATUS] &= ~S_TXFIFOEMP;
 283         fifo32_push(&s->tx_fifo, value);
 284         if (fifo32_num_used(&s->tx_fifo) == (s->fifo_depth - 1)) {
 285             s->regs[R_SPI_STATUS] |= S_TXFIFOFULNXT;
 286         } else if (fifo32_num_used(&s->tx_fifo) == s->fifo_depth) {
 287             s->regs[R_SPI_STATUS] |= S_TXFIFOFUL;
 288         }
 289         if (s->enabled) {
 290             spi_flush_txfifo(s);
 291         }
 292         break;
 293
 294     case R_SPI_CONTROL:
 295         s->regs[R_SPI_CONTROL] = value;
 296         if (value & C_BIGFIFO) {
 297             set_fifodepth(s);
 298         } else {
 299             s->fifo_depth = 4;
 300         }
 301         s->enabled = value & C_ENABLE;
 302         s->frame_count = (value & FMCOUNT_MASK) >> FMCOUNT_SHIFT;
 303         if (value & C_RESET) {
 304             mss_spi_reset(DEVICE(s));
 305         }
 306         break;
 307
 308     case R_SPI_DFSIZE:
 309         if (s->enabled) {
 310             break;
 311         }
 312         /*
 313          * [31:6] bits are reserved bits and for future use.
 314          * [5:0] are for frame size. Only [5:0] bits are validated
 315          * during write, [31:6] bits are untouched.
 316          */
 317         if ((value & FRAMESZ_MASK) > FRAMESZ_MAX) {
 318             qemu_log_mask(LOG_GUEST_ERROR, "%s: Incorrect size %u provided."
 319                          "Maximum frame size is %u\n",
 320                          __func__, value & FRAMESZ_MASK, FRAMESZ_MAX);
 321             break;
 322         }
 323         s->regs[R_SPI_DFSIZE] = value;
 324         break;
 325
 326     case R_SPI_INTCLR:
 327         s->regs[R_SPI_INTCLR] = value;
 328         if (value & S_TXDONE) {
 329             s->regs[R_SPI_RIS] &= ~S_TXDONE;
 330         }
 331         if (value & S_RXRDY) {
 332             s->regs[R_SPI_RIS] &= ~S_RXRDY;
 333         }
 334         if (value & S_RXCHOVRF) {
 335             s->regs[R_SPI_RIS] &= ~S_RXCHOVRF;
 336         }
 337         break;
 338
 339     case R_SPI_MIS:
 340     case R_SPI_STATUS:
 341     case R_SPI_RIS:
 342             qemu_log_mask(LOG_GUEST_ERROR,
 343                          "%s: Write to read only register 0x%" HWADDR_PRIx "\n",
 344                          __func__, addr * 4);
 345         break;
 346
 347     default:
 348         if (addr < ARRAY_SIZE(s->regs)) {
 349             s->regs[addr] = value;
 350         } else {
 351             qemu_log_mask(LOG_GUEST_ERROR,
 352                          "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__,
 353                          addr * 4);
 354         }
 355         break;
 356     }
 357
 358     spi_update_irq(s);
 359 }
 360
 361 static const MemoryRegionOps spi_ops = {
 362     .read = spi_read,
 363     .write = spi_write,
 364     .endianness = DEVICE_NATIVE_ENDIAN,
 365     .valid = {
 366         .min_access_size = 1,
 367         .max_access_size = 4
 368     }
 369 };
 370
 371 static void mss_spi_realize(DeviceState *dev, Error **errp)
 372 {
 373     MSSSpiState *s = MSS_SPI(dev);
 374     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 375
 376     s->spi = ssi_create_bus(dev, "spi");
 377
 378     sysbus_init_irq(sbd, &s->irq);
 379     sysbus_init_irq(sbd, &s->cs_line);
 380
 381     memory_region_init_io(&s->mmio, OBJECT(s), &spi_ops, s,
 382                           TYPE_MSS_SPI, R_SPI_MAX * 4);
 383     sysbus_init_mmio(sbd, &s->mmio);
 384
 385     fifo32_create(&s->tx_fifo, FIFO_CAPACITY);
 386     fifo32_create(&s->rx_fifo, FIFO_CAPACITY);
 387 }
 388
 389 static const VMStateDescription vmstate_mss_spi = {
 390     .name = TYPE_MSS_SPI,
 391     .version_id = 1,
 392     .minimum_version_id = 1,
 393     .fields = (const VMStateField[]) {
 394         VMSTATE_FIFO32(tx_fifo, MSSSpiState),
 395         VMSTATE_FIFO32(rx_fifo, MSSSpiState),
 396         VMSTATE_UINT32_ARRAY(regs, MSSSpiState, R_SPI_MAX),
 397         VMSTATE_END_OF_LIST()
 398     }
 399 };
 400
 401 static void mss_spi_class_init(ObjectClass *klass, void *data)
 402 {
 403     DeviceClass *dc = DEVICE_CLASS(klass);
 404
 405     dc->realize = mss_spi_realize;
 406     device_class_set_legacy_reset(dc, mss_spi_reset);
 407     dc->vmsd = &vmstate_mss_spi;
 408 }
 409
 410 static const TypeInfo mss_spi_info = {
 411     .name           = TYPE_MSS_SPI,
 412     .parent         = TYPE_SYS_BUS_DEVICE,
 413     .instance_size  = sizeof(MSSSpiState),
 414     .class_init     = mss_spi_class_init,
 415 };
 416
 417 static void mss_spi_register_types(void)
 418 {
 419     type_register_static(&mss_spi_info);
 420 }
 421
 422 type_init(mss_spi_register_types)