hw/ssi/xilinx_spi.c

   1 /*
   2  * QEMU model of the Xilinx SPI Controller
   3  *
   4  * Copyright (C) 2010 Edgar E. Iglesias.
   5  * Copyright (C) 2012 Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
   6  * Copyright (C) 2012 PetaLogix
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  */
  26
  27 #include "qemu/osdep.h"
  28 #include "hw/sysbus.h"
  29 #include "migration/vmstate.h"
  30 #include "qemu/module.h"
  31 #include "qemu/fifo8.h"
  32
  33 #include "hw/irq.h"
  34 #include "hw/qdev-properties.h"
  35 #include "hw/ssi/ssi.h"
  36 #include "qom/object.h"
  37
  38 #ifdef XILINX_SPI_ERR_DEBUG
  39 #define DB_PRINT(...) do { \
  40     fprintf(stderr,  ": %s: ", __func__); \
  41     fprintf(stderr, ## __VA_ARGS__); \
  42     } while (0)
  43 #else
  44     #define DB_PRINT(...)
  45 #endif
  46
  47 #define R_DGIER     (0x1c / 4)
  48 #define R_DGIER_IE  (1 << 31)
  49
  50 #define R_IPISR     (0x20 / 4)
  51 #define IRQ_DRR_NOT_EMPTY    (1 << (31 - 23))
  52 #define IRQ_DRR_OVERRUN      (1 << (31 - 26))
  53 #define IRQ_DRR_FULL         (1 << (31 - 27))
  54 #define IRQ_TX_FF_HALF_EMPTY (1 << 6)
  55 #define IRQ_DTR_UNDERRUN     (1 << 3)
  56 #define IRQ_DTR_EMPTY        (1 << (31 - 29))
  57
  58 #define R_IPIER     (0x28 / 4)
  59 #define R_SRR       (0x40 / 4)
  60 #define R_SPICR     (0x60 / 4)
  61 #define R_SPICR_TXFF_RST     (1 << 5)
  62 #define R_SPICR_RXFF_RST     (1 << 6)
  63 #define R_SPICR_MTI          (1 << 8)
  64
  65 #define R_SPISR     (0x64 / 4)
  66 #define SR_TX_FULL    (1 << 3)
  67 #define SR_TX_EMPTY   (1 << 2)
  68 #define SR_RX_FULL    (1 << 1)
  69 #define SR_RX_EMPTY   (1 << 0)
  70
  71 #define R_SPIDTR    (0x68 / 4)
  72 #define R_SPIDRR    (0x6C / 4)
  73 #define R_SPISSR    (0x70 / 4)
  74 #define R_TX_FF_OCY (0x74 / 4)
  75 #define R_RX_FF_OCY (0x78 / 4)
  76 #define R_MAX       (0x7C / 4)
  77
  78 #define FIFO_CAPACITY 256
  79
  80 #define TYPE_XILINX_SPI "xlnx.xps-spi"
  81 OBJECT_DECLARE_SIMPLE_TYPE(XilinxSPI, XILINX_SPI)
  82
  83 struct XilinxSPI {
  84     SysBusDevice parent_obj;
  85
  86     MemoryRegion mmio;
  87
  88     qemu_irq irq;
  89     int irqline;
  90
  91     uint8_t num_cs;
  92     qemu_irq *cs_lines;
  93
  94     SSIBus *spi;
  95
  96     Fifo8 rx_fifo;
  97     Fifo8 tx_fifo;
  98
  99     uint32_t regs[R_MAX];
 100 };
 101
 102 static void txfifo_reset(XilinxSPI *s)
 103 {
 104     fifo8_reset(&s->tx_fifo);
 105
 106     s->regs[R_SPISR] &= ~SR_TX_FULL;
 107     s->regs[R_SPISR] |= SR_TX_EMPTY;
 108 }
 109
 110 static void rxfifo_reset(XilinxSPI *s)
 111 {
 112     fifo8_reset(&s->rx_fifo);
 113
 114     s->regs[R_SPISR] |= SR_RX_EMPTY;
 115     s->regs[R_SPISR] &= ~SR_RX_FULL;
 116 }
 117
 118 static void xlx_spi_update_cs(XilinxSPI *s)
 119 {
 120     int i;
 121
 122     for (i = 0; i < s->num_cs; ++i) {
 123         qemu_set_irq(s->cs_lines[i], !(~s->regs[R_SPISSR] & 1 << i));
 124     }
 125 }
 126
 127 static void xlx_spi_update_irq(XilinxSPI *s)
 128 {
 129     uint32_t pending;
 130
 131     s->regs[R_IPISR] |=
 132             (!fifo8_is_empty(&s->rx_fifo) ? IRQ_DRR_NOT_EMPTY : 0) |
 133             (fifo8_is_full(&s->rx_fifo) ? IRQ_DRR_FULL : 0);
 134
 135     pending = s->regs[R_IPISR] & s->regs[R_IPIER];
 136
 137     pending = pending && (s->regs[R_DGIER] & R_DGIER_IE);
 138     pending = !!pending;
 139
 140     /* This call lies right in the data paths so don't call the
 141        irq chain unless things really changed.  */
 142     if (pending != s->irqline) {
 143         s->irqline = pending;
 144         DB_PRINT("irq_change of state %u ISR:%x IER:%X\n",
 145                     pending, s->regs[R_IPISR], s->regs[R_IPIER]);
 146         qemu_set_irq(s->irq, pending);
 147     }
 148
 149 }
 150
 151 static void xlx_spi_do_reset(XilinxSPI *s)
 152 {
 153     memset(s->regs, 0, sizeof s->regs);
 154
 155     rxfifo_reset(s);
 156     txfifo_reset(s);
 157
 158     s->regs[R_SPISSR] = ~0;
 159     xlx_spi_update_irq(s);
 160     xlx_spi_update_cs(s);
 161 }
 162
 163 static void xlx_spi_reset(DeviceState *d)
 164 {
 165     xlx_spi_do_reset(XILINX_SPI(d));
 166 }
 167
 168 static inline int spi_master_enabled(XilinxSPI *s)
 169 {
 170     return !(s->regs[R_SPICR] & R_SPICR_MTI);
 171 }
 172
 173 static void spi_flush_txfifo(XilinxSPI *s)
 174 {
 175     uint32_t tx;
 176     uint32_t rx;
 177
 178     while (!fifo8_is_empty(&s->tx_fifo)) {
 179         tx = (uint32_t)fifo8_pop(&s->tx_fifo);
 180         DB_PRINT("data tx:%x\n", tx);
 181         rx = ssi_transfer(s->spi, tx);
 182         DB_PRINT("data rx:%x\n", rx);
 183         if (fifo8_is_full(&s->rx_fifo)) {
 184             s->regs[R_IPISR] |= IRQ_DRR_OVERRUN;
 185         } else {
 186             fifo8_push(&s->rx_fifo, (uint8_t)rx);
 187             if (fifo8_is_full(&s->rx_fifo)) {
 188                 s->regs[R_SPISR] |= SR_RX_FULL;
 189                 s->regs[R_IPISR] |= IRQ_DRR_FULL;
 190             }
 191         }
 192
 193         s->regs[R_SPISR] &= ~SR_RX_EMPTY;
 194         s->regs[R_SPISR] &= ~SR_TX_FULL;
 195         s->regs[R_SPISR] |= SR_TX_EMPTY;
 196
 197         s->regs[R_IPISR] |= IRQ_DTR_EMPTY;
 198         s->regs[R_IPISR] |= IRQ_DRR_NOT_EMPTY;
 199     }
 200
 201 }
 202
 203 static uint64_t
 204 spi_read(void *opaque, hwaddr addr, unsigned int size)
 205 {
 206     XilinxSPI *s = opaque;
 207     uint32_t r = 0;
 208
 209     addr >>= 2;
 210     switch (addr) {
 211     case R_SPIDRR:
 212         if (fifo8_is_empty(&s->rx_fifo)) {
 213             DB_PRINT("Read from empty FIFO!\n");
 214             return 0xdeadbeef;
 215         }
 216
 217         s->regs[R_SPISR] &= ~SR_RX_FULL;
 218         r = fifo8_pop(&s->rx_fifo);
 219         if (fifo8_is_empty(&s->rx_fifo)) {
 220             s->regs[R_SPISR] |= SR_RX_EMPTY;
 221         }
 222         break;
 223
 224     case R_SPISR:
 225         r = s->regs[addr];
 226         break;
 227
 228     default:
 229         if (addr < ARRAY_SIZE(s->regs)) {
 230             r = s->regs[addr];
 231         }
 232         break;
 233
 234     }
 235     DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr * 4, r);
 236     xlx_spi_update_irq(s);
 237     return r;
 238 }
 239
 240 static void
 241 spi_write(void *opaque, hwaddr addr,
 242             uint64_t val64, unsigned int size)
 243 {
 244     XilinxSPI *s = opaque;
 245     uint32_t value = val64;
 246
 247     DB_PRINT("addr=" TARGET_FMT_plx " = %x\n", addr, value);
 248     addr >>= 2;
 249     switch (addr) {
 250     case R_SRR:
 251         if (value != 0xa) {
 252             DB_PRINT("Invalid write to SRR %x\n", value);
 253         } else {
 254             xlx_spi_do_reset(s);
 255         }
 256         break;
 257
 258     case R_SPIDTR:
 259         s->regs[R_SPISR] &= ~SR_TX_EMPTY;
 260         fifo8_push(&s->tx_fifo, (uint8_t)value);
 261         if (fifo8_is_full(&s->tx_fifo)) {
 262             s->regs[R_SPISR] |= SR_TX_FULL;
 263         }
 264         if (!spi_master_enabled(s)) {
 265             goto done;
 266         } else {
 267             DB_PRINT("DTR and master enabled\n");
 268         }
 269         spi_flush_txfifo(s);
 270         break;
 271
 272     case R_SPISR:
 273         DB_PRINT("Invalid write to SPISR %x\n", value);
 274         break;
 275
 276     case R_IPISR:
 277         /* Toggle the bits.  */
 278         s->regs[addr] ^= value;
 279         break;
 280
 281     /* Slave Select Register.  */
 282     case R_SPISSR:
 283         s->regs[addr] = value;
 284         xlx_spi_update_cs(s);
 285         break;
 286
 287     case R_SPICR:
 288         /* FIXME: reset irq and sr state to empty queues.  */
 289         if (value & R_SPICR_RXFF_RST) {
 290             rxfifo_reset(s);
 291         }
 292
 293         if (value & R_SPICR_TXFF_RST) {
 294             txfifo_reset(s);
 295         }
 296         value &= ~(R_SPICR_RXFF_RST | R_SPICR_TXFF_RST);
 297         s->regs[addr] = value;
 298
 299         if (!(value & R_SPICR_MTI)) {
 300             spi_flush_txfifo(s);
 301         }
 302         break;
 303
 304     default:
 305         if (addr < ARRAY_SIZE(s->regs)) {
 306             s->regs[addr] = value;
 307         }
 308         break;
 309     }
 310
 311 done:
 312     xlx_spi_update_irq(s);
 313 }
 314
 315 static const MemoryRegionOps spi_ops = {
 316     .read = spi_read,
 317     .write = spi_write,
 318     .endianness = DEVICE_NATIVE_ENDIAN,
 319     .valid = {
 320         .min_access_size = 4,
 321         .max_access_size = 4
 322     }
 323 };
 324
 325 static void xilinx_spi_realize(DeviceState *dev, Error **errp)
 326 {
 327     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 328     XilinxSPI *s = XILINX_SPI(dev);
 329     int i;
 330
 331     DB_PRINT("\n");
 332
 333     s->spi = ssi_create_bus(dev, "spi");
 334
 335     sysbus_init_irq(sbd, &s->irq);
 336     s->cs_lines = g_new0(qemu_irq, s->num_cs);
 337     for (i = 0; i < s->num_cs; ++i) {
 338         sysbus_init_irq(sbd, &s->cs_lines[i]);
 339     }
 340
 341     memory_region_init_io(&s->mmio, OBJECT(s), &spi_ops, s,
 342                           "xilinx-spi", R_MAX * 4);
 343     sysbus_init_mmio(sbd, &s->mmio);
 344
 345     s->irqline = -1;
 346
 347     fifo8_create(&s->tx_fifo, FIFO_CAPACITY);
 348     fifo8_create(&s->rx_fifo, FIFO_CAPACITY);
 349 }
 350
 351 static const VMStateDescription vmstate_xilinx_spi = {
 352     .name = "xilinx_spi",
 353     .version_id = 1,
 354     .minimum_version_id = 1,
 355     .fields = (VMStateField[]) {
 356         VMSTATE_FIFO8(tx_fifo, XilinxSPI),
 357         VMSTATE_FIFO8(rx_fifo, XilinxSPI),
 358         VMSTATE_UINT32_ARRAY(regs, XilinxSPI, R_MAX),
 359         VMSTATE_END_OF_LIST()
 360     }
 361 };
 362
 363 static Property xilinx_spi_properties[] = {
 364     DEFINE_PROP_UINT8("num-ss-bits", XilinxSPI, num_cs, 1),
 365     DEFINE_PROP_END_OF_LIST(),
 366 };
 367
 368 static void xilinx_spi_class_init(ObjectClass *klass, void *data)
 369 {
 370     DeviceClass *dc = DEVICE_CLASS(klass);
 371
 372     dc->realize = xilinx_spi_realize;
 373     dc->reset = xlx_spi_reset;
 374     device_class_set_props(dc, xilinx_spi_properties);
 375     dc->vmsd = &vmstate_xilinx_spi;
 376 }
 377
 378 static const TypeInfo xilinx_spi_info = {
 379     .name           = TYPE_XILINX_SPI,
 380     .parent         = TYPE_SYS_BUS_DEVICE,
 381     .instance_size  = sizeof(XilinxSPI),
 382     .class_init     = xilinx_spi_class_init,
 383 };
 384
 385 static void xilinx_spi_register_types(void)
 386 {
 387     type_register_static(&xilinx_spi_info);
 388 }
 389
 390 type_init(xilinx_spi_register_types)