hw/char/cadence_uart.c

   1 /*
   2  * Device model for Cadence UART
   3  *
   4  * Reference: Xilinx Zynq 7000 reference manual
   5  *   - http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf
   6  *   - Chapter 19 UART Controller
   7  *   - Appendix B for Register details
   8  *
   9  * Copyright (c) 2010 Xilinx Inc.
  10  * Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
  11  * Copyright (c) 2012 PetaLogix Pty Ltd.
  12  * Written by Haibing Ma
  13  *            M.Habib
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #include "qemu/osdep.h"
  25 #include "hw/sysbus.h"
  26 #include "sysemu/char.h"
  27 #include "qemu/timer.h"
  28 #include "qemu/log.h"
  29 #include "hw/char/cadence_uart.h"
  30
  31 #ifdef CADENCE_UART_ERR_DEBUG
  32 #define DB_PRINT(...) do { \
  33     fprintf(stderr,  ": %s: ", __func__); \
  34     fprintf(stderr, ## __VA_ARGS__); \
  35     } while (0);
  36 #else
  37     #define DB_PRINT(...)
  38 #endif
  39
  40 #define UART_SR_INTR_RTRIG     0x00000001
  41 #define UART_SR_INTR_REMPTY    0x00000002
  42 #define UART_SR_INTR_RFUL      0x00000004
  43 #define UART_SR_INTR_TEMPTY    0x00000008
  44 #define UART_SR_INTR_TFUL      0x00000010
  45 /* somewhat awkwardly, TTRIG is misaligned between SR and ISR */
  46 #define UART_SR_TTRIG          0x00002000
  47 #define UART_INTR_TTRIG        0x00000400
  48 /* bits fields in CSR that correlate to CISR. If any of these bits are set in
  49  * SR, then the same bit in CISR is set high too */
  50 #define UART_SR_TO_CISR_MASK   0x0000001F
  51
  52 #define UART_INTR_ROVR         0x00000020
  53 #define UART_INTR_FRAME        0x00000040
  54 #define UART_INTR_PARE         0x00000080
  55 #define UART_INTR_TIMEOUT      0x00000100
  56 #define UART_INTR_DMSI         0x00000200
  57 #define UART_INTR_TOVR         0x00001000
  58
  59 #define UART_SR_RACTIVE    0x00000400
  60 #define UART_SR_TACTIVE    0x00000800
  61 #define UART_SR_FDELT      0x00001000
  62
  63 #define UART_CR_RXRST       0x00000001
  64 #define UART_CR_TXRST       0x00000002
  65 #define UART_CR_RX_EN       0x00000004
  66 #define UART_CR_RX_DIS      0x00000008
  67 #define UART_CR_TX_EN       0x00000010
  68 #define UART_CR_TX_DIS      0x00000020
  69 #define UART_CR_RST_TO      0x00000040
  70 #define UART_CR_STARTBRK    0x00000080
  71 #define UART_CR_STOPBRK     0x00000100
  72
  73 #define UART_MR_CLKS            0x00000001
  74 #define UART_MR_CHRL            0x00000006
  75 #define UART_MR_CHRL_SH         1
  76 #define UART_MR_PAR             0x00000038
  77 #define UART_MR_PAR_SH          3
  78 #define UART_MR_NBSTOP          0x000000C0
  79 #define UART_MR_NBSTOP_SH       6
  80 #define UART_MR_CHMODE          0x00000300
  81 #define UART_MR_CHMODE_SH       8
  82 #define UART_MR_UCLKEN          0x00000400
  83 #define UART_MR_IRMODE          0x00000800
  84
  85 #define UART_DATA_BITS_6       (0x3 << UART_MR_CHRL_SH)
  86 #define UART_DATA_BITS_7       (0x2 << UART_MR_CHRL_SH)
  87 #define UART_PARITY_ODD        (0x1 << UART_MR_PAR_SH)
  88 #define UART_PARITY_EVEN       (0x0 << UART_MR_PAR_SH)
  89 #define UART_STOP_BITS_1       (0x3 << UART_MR_NBSTOP_SH)
  90 #define UART_STOP_BITS_2       (0x2 << UART_MR_NBSTOP_SH)
  91 #define NORMAL_MODE            (0x0 << UART_MR_CHMODE_SH)
  92 #define ECHO_MODE              (0x1 << UART_MR_CHMODE_SH)
  93 #define LOCAL_LOOPBACK         (0x2 << UART_MR_CHMODE_SH)
  94 #define REMOTE_LOOPBACK        (0x3 << UART_MR_CHMODE_SH)
  95
  96 #define UART_INPUT_CLK         50000000
  97
  98 #define R_CR       (0x00/4)
  99 #define R_MR       (0x04/4)
 100 #define R_IER      (0x08/4)
 101 #define R_IDR      (0x0C/4)
 102 #define R_IMR      (0x10/4)
 103 #define R_CISR     (0x14/4)
 104 #define R_BRGR     (0x18/4)
 105 #define R_RTOR     (0x1C/4)
 106 #define R_RTRIG    (0x20/4)
 107 #define R_MCR      (0x24/4)
 108 #define R_MSR      (0x28/4)
 109 #define R_SR       (0x2C/4)
 110 #define R_TX_RX    (0x30/4)
 111 #define R_BDIV     (0x34/4)
 112 #define R_FDEL     (0x38/4)
 113 #define R_PMIN     (0x3C/4)
 114 #define R_PWID     (0x40/4)
 115 #define R_TTRIG    (0x44/4)
 116
 117
 118 static void uart_update_status(CadenceUARTState *s)
 119 {
 120     s->r[R_SR] = 0;
 121
 122     s->r[R_SR] |= s->rx_count == CADENCE_UART_RX_FIFO_SIZE ? UART_SR_INTR_RFUL
 123                                                            : 0;
 124     s->r[R_SR] |= !s->rx_count ? UART_SR_INTR_REMPTY : 0;
 125     s->r[R_SR] |= s->rx_count >= s->r[R_RTRIG] ? UART_SR_INTR_RTRIG : 0;
 126
 127     s->r[R_SR] |= s->tx_count == CADENCE_UART_TX_FIFO_SIZE ? UART_SR_INTR_TFUL
 128                                                            : 0;
 129     s->r[R_SR] |= !s->tx_count ? UART_SR_INTR_TEMPTY : 0;
 130     s->r[R_SR] |= s->tx_count >= s->r[R_TTRIG] ? UART_SR_TTRIG : 0;
 131
 132     s->r[R_CISR] |= s->r[R_SR] & UART_SR_TO_CISR_MASK;
 133     s->r[R_CISR] |= s->r[R_SR] & UART_SR_TTRIG ? UART_INTR_TTRIG : 0;
 134     qemu_set_irq(s->irq, !!(s->r[R_IMR] & s->r[R_CISR]));
 135 }
 136
 137 static void fifo_trigger_update(void *opaque)
 138 {
 139     CadenceUARTState *s = opaque;
 140
 141     if (s->r[R_RTOR]) {
 142         s->r[R_CISR] |= UART_INTR_TIMEOUT;
 143         uart_update_status(s);
 144     }
 145 }
 146
 147 static void uart_rx_reset(CadenceUARTState *s)
 148 {
 149     s->rx_wpos = 0;
 150     s->rx_count = 0;
 151     qemu_chr_fe_accept_input(&s->chr);
 152 }
 153
 154 static void uart_tx_reset(CadenceUARTState *s)
 155 {
 156     s->tx_count = 0;
 157 }
 158
 159 static void uart_send_breaks(CadenceUARTState *s)
 160 {
 161     int break_enabled = 1;
 162
 163     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 164                       &break_enabled);
 165 }
 166
 167 static void uart_parameters_setup(CadenceUARTState *s)
 168 {
 169     QEMUSerialSetParams ssp;
 170     unsigned int baud_rate, packet_size;
 171
 172     baud_rate = (s->r[R_MR] & UART_MR_CLKS) ?
 173             UART_INPUT_CLK / 8 : UART_INPUT_CLK;
 174
 175     ssp.speed = baud_rate / (s->r[R_BRGR] * (s->r[R_BDIV] + 1));
 176     packet_size = 1;
 177
 178     switch (s->r[R_MR] & UART_MR_PAR) {
 179     case UART_PARITY_EVEN:
 180         ssp.parity = 'E';
 181         packet_size++;
 182         break;
 183     case UART_PARITY_ODD:
 184         ssp.parity = 'O';
 185         packet_size++;
 186         break;
 187     default:
 188         ssp.parity = 'N';
 189         break;
 190     }
 191
 192     switch (s->r[R_MR] & UART_MR_CHRL) {
 193     case UART_DATA_BITS_6:
 194         ssp.data_bits = 6;
 195         break;
 196     case UART_DATA_BITS_7:
 197         ssp.data_bits = 7;
 198         break;
 199     default:
 200         ssp.data_bits = 8;
 201         break;
 202     }
 203
 204     switch (s->r[R_MR] & UART_MR_NBSTOP) {
 205     case UART_STOP_BITS_1:
 206         ssp.stop_bits = 1;
 207         break;
 208     default:
 209         ssp.stop_bits = 2;
 210         break;
 211     }
 212
 213     packet_size += ssp.data_bits + ssp.stop_bits;
 214     s->char_tx_time = (NANOSECONDS_PER_SECOND / ssp.speed) * packet_size;
 215     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 216 }
 217
 218 static int uart_can_receive(void *opaque)
 219 {
 220     CadenceUARTState *s = opaque;
 221     int ret = MAX(CADENCE_UART_RX_FIFO_SIZE, CADENCE_UART_TX_FIFO_SIZE);
 222     uint32_t ch_mode = s->r[R_MR] & UART_MR_CHMODE;
 223
 224     if (ch_mode == NORMAL_MODE || ch_mode == ECHO_MODE) {
 225         ret = MIN(ret, CADENCE_UART_RX_FIFO_SIZE - s->rx_count);
 226     }
 227     if (ch_mode == REMOTE_LOOPBACK || ch_mode == ECHO_MODE) {
 228         ret = MIN(ret, CADENCE_UART_TX_FIFO_SIZE - s->tx_count);
 229     }
 230     return ret;
 231 }
 232
 233 static void uart_ctrl_update(CadenceUARTState *s)
 234 {
 235     if (s->r[R_CR] & UART_CR_TXRST) {
 236         uart_tx_reset(s);
 237     }
 238
 239     if (s->r[R_CR] & UART_CR_RXRST) {
 240         uart_rx_reset(s);
 241     }
 242
 243     s->r[R_CR] &= ~(UART_CR_TXRST | UART_CR_RXRST);
 244
 245     if (s->r[R_CR] & UART_CR_STARTBRK && !(s->r[R_CR] & UART_CR_STOPBRK)) {
 246         uart_send_breaks(s);
 247     }
 248 }
 249
 250 static void uart_write_rx_fifo(void *opaque, const uint8_t *buf, int size)
 251 {
 252     CadenceUARTState *s = opaque;
 253     uint64_t new_rx_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 254     int i;
 255
 256     if ((s->r[R_CR] & UART_CR_RX_DIS) || !(s->r[R_CR] & UART_CR_RX_EN)) {
 257         return;
 258     }
 259
 260     if (s->rx_count == CADENCE_UART_RX_FIFO_SIZE) {
 261         s->r[R_CISR] |= UART_INTR_ROVR;
 262     } else {
 263         for (i = 0; i < size; i++) {
 264             s->rx_fifo[s->rx_wpos] = buf[i];
 265             s->rx_wpos = (s->rx_wpos + 1) % CADENCE_UART_RX_FIFO_SIZE;
 266             s->rx_count++;
 267         }
 268         timer_mod(s->fifo_trigger_handle, new_rx_time +
 269                                                 (s->char_tx_time * 4));
 270     }
 271     uart_update_status(s);
 272 }
 273
 274 static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
 275                                   void *opaque)
 276 {
 277     CadenceUARTState *s = opaque;
 278     int ret;
 279
 280     /* instant drain the fifo when there's no back-end */
 281     if (!qemu_chr_fe_get_driver(&s->chr)) {
 282         s->tx_count = 0;
 283         return FALSE;
 284     }
 285
 286     if (!s->tx_count) {
 287         return FALSE;
 288     }
 289
 290     ret = qemu_chr_fe_write(&s->chr, s->tx_fifo, s->tx_count);
 291
 292     if (ret >= 0) {
 293         s->tx_count -= ret;
 294         memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count);
 295     }
 296
 297     if (s->tx_count) {
 298         guint r = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 299                                         cadence_uart_xmit, s);
 300         if (!r) {
 301             s->tx_count = 0;
 302             return FALSE;
 303         }
 304     }
 305
 306     uart_update_status(s);
 307     return FALSE;
 308 }
 309
 310 static void uart_write_tx_fifo(CadenceUARTState *s, const uint8_t *buf,
 311                                int size)
 312 {
 313     if ((s->r[R_CR] & UART_CR_TX_DIS) || !(s->r[R_CR] & UART_CR_TX_EN)) {
 314         return;
 315     }
 316
 317     if (size > CADENCE_UART_TX_FIFO_SIZE - s->tx_count) {
 318         size = CADENCE_UART_TX_FIFO_SIZE - s->tx_count;
 319         /*
 320          * This can only be a guest error via a bad tx fifo register push,
 321          * as can_receive() should stop remote loop and echo modes ever getting
 322          * us to here.
 323          */
 324         qemu_log_mask(LOG_GUEST_ERROR, "cadence_uart: TxFIFO overflow");
 325         s->r[R_CISR] |= UART_INTR_ROVR;
 326     }
 327
 328     memcpy(s->tx_fifo + s->tx_count, buf, size);
 329     s->tx_count += size;
 330
 331     cadence_uart_xmit(NULL, G_IO_OUT, s);
 332 }
 333
 334 static void uart_receive(void *opaque, const uint8_t *buf, int size)
 335 {
 336     CadenceUARTState *s = opaque;
 337     uint32_t ch_mode = s->r[R_MR] & UART_MR_CHMODE;
 338
 339     if (ch_mode == NORMAL_MODE || ch_mode == ECHO_MODE) {
 340         uart_write_rx_fifo(opaque, buf, size);
 341     }
 342     if (ch_mode == REMOTE_LOOPBACK || ch_mode == ECHO_MODE) {
 343         uart_write_tx_fifo(s, buf, size);
 344     }
 345 }
 346
 347 static void uart_event(void *opaque, int event)
 348 {
 349     CadenceUARTState *s = opaque;
 350     uint8_t buf = '\0';
 351
 352     if (event == CHR_EVENT_BREAK) {
 353         uart_write_rx_fifo(opaque, &buf, 1);
 354     }
 355
 356     uart_update_status(s);
 357 }
 358
 359 static void uart_read_rx_fifo(CadenceUARTState *s, uint32_t *c)
 360 {
 361     if ((s->r[R_CR] & UART_CR_RX_DIS) || !(s->r[R_CR] & UART_CR_RX_EN)) {
 362         return;
 363     }
 364
 365     if (s->rx_count) {
 366         uint32_t rx_rpos = (CADENCE_UART_RX_FIFO_SIZE + s->rx_wpos -
 367                             s->rx_count) % CADENCE_UART_RX_FIFO_SIZE;
 368         *c = s->rx_fifo[rx_rpos];
 369         s->rx_count--;
 370
 371         qemu_chr_fe_accept_input(&s->chr);
 372     } else {
 373         *c = 0;
 374     }
 375
 376     uart_update_status(s);
 377 }
 378
 379 static void uart_write(void *opaque, hwaddr offset,
 380                           uint64_t value, unsigned size)
 381 {
 382     CadenceUARTState *s = opaque;
 383
 384     DB_PRINT(" offset:%x data:%08x\n", (unsigned)offset, (unsigned)value);
 385     offset >>= 2;
 386     if (offset >= CADENCE_UART_R_MAX) {
 387         return;
 388     }
 389     switch (offset) {
 390     case R_IER: /* ier (wts imr) */
 391         s->r[R_IMR] |= value;
 392         break;
 393     case R_IDR: /* idr (wtc imr) */
 394         s->r[R_IMR] &= ~value;
 395         break;
 396     case R_IMR: /* imr (read only) */
 397         break;
 398     case R_CISR: /* cisr (wtc) */
 399         s->r[R_CISR] &= ~value;
 400         break;
 401     case R_TX_RX: /* UARTDR */
 402         switch (s->r[R_MR] & UART_MR_CHMODE) {
 403         case NORMAL_MODE:
 404             uart_write_tx_fifo(s, (uint8_t *) &value, 1);
 405             break;
 406         case LOCAL_LOOPBACK:
 407             uart_write_rx_fifo(opaque, (uint8_t *) &value, 1);
 408             break;
 409         }
 410         break;
 411     case R_BRGR: /* Baud rate generator */
 412         if (value >= 0x01) {
 413             s->r[offset] = value & 0xFFFF;
 414         }
 415         break;
 416     case R_BDIV:    /* Baud rate divider */
 417         if (value >= 0x04) {
 418             s->r[offset] = value & 0xFF;
 419         }
 420         break;
 421     default:
 422         s->r[offset] = value;
 423     }
 424
 425     switch (offset) {
 426     case R_CR:
 427         uart_ctrl_update(s);
 428         break;
 429     case R_MR:
 430         uart_parameters_setup(s);
 431         break;
 432     }
 433     uart_update_status(s);
 434 }
 435
 436 static uint64_t uart_read(void *opaque, hwaddr offset,
 437         unsigned size)
 438 {
 439     CadenceUARTState *s = opaque;
 440     uint32_t c = 0;
 441
 442     offset >>= 2;
 443     if (offset >= CADENCE_UART_R_MAX) {
 444         c = 0;
 445     } else if (offset == R_TX_RX) {
 446         uart_read_rx_fifo(s, &c);
 447     } else {
 448        c = s->r[offset];
 449     }
 450
 451     DB_PRINT(" offset:%x data:%08x\n", (unsigned)(offset << 2), (unsigned)c);
 452     return c;
 453 }
 454
 455 static const MemoryRegionOps uart_ops = {
 456     .read = uart_read,
 457     .write = uart_write,
 458     .endianness = DEVICE_NATIVE_ENDIAN,
 459 };
 460
 461 static void cadence_uart_reset(DeviceState *dev)
 462 {
 463     CadenceUARTState *s = CADENCE_UART(dev);
 464
 465     s->r[R_CR] = 0x00000128;
 466     s->r[R_IMR] = 0;
 467     s->r[R_CISR] = 0;
 468     s->r[R_RTRIG] = 0x00000020;
 469     s->r[R_BRGR] = 0x0000028B;
 470     s->r[R_BDIV] = 0x0000000F;
 471     s->r[R_TTRIG] = 0x00000020;
 472
 473     uart_rx_reset(s);
 474     uart_tx_reset(s);
 475
 476     uart_update_status(s);
 477 }
 478
 479 static void cadence_uart_realize(DeviceState *dev, Error **errp)
 480 {
 481     CadenceUARTState *s = CADENCE_UART(dev);
 482
 483     s->fifo_trigger_handle = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 484                                           fifo_trigger_update, s);
 485
 486     qemu_chr_fe_set_handlers(&s->chr, uart_can_receive, uart_receive,
 487                              uart_event, s, NULL, true);
 488 }
 489
 490 static void cadence_uart_init(Object *obj)
 491 {
 492     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
 493     CadenceUARTState *s = CADENCE_UART(obj);
 494
 495     memory_region_init_io(&s->iomem, obj, &uart_ops, s, "uart", 0x1000);
 496     sysbus_init_mmio(sbd, &s->iomem);
 497     sysbus_init_irq(sbd, &s->irq);
 498
 499     s->char_tx_time = (NANOSECONDS_PER_SECOND / 9600) * 10;
 500 }
 501
 502 static int cadence_uart_post_load(void *opaque, int version_id)
 503 {
 504     CadenceUARTState *s = opaque;
 505
 506     /* Ensure these two aren't invalid numbers */
 507     if (s->r[R_BRGR] < 1 || s->r[R_BRGR] & ~0xFFFF ||
 508         s->r[R_BDIV] <= 3 || s->r[R_BDIV] & ~0xFF) {
 509         /* Value is invalid, abort */
 510         return 1;
 511     }
 512
 513     uart_parameters_setup(s);
 514     uart_update_status(s);
 515     return 0;
 516 }
 517
 518 static const VMStateDescription vmstate_cadence_uart = {
 519     .name = "cadence_uart",
 520     .version_id = 2,
 521     .minimum_version_id = 2,
 522     .post_load = cadence_uart_post_load,
 523     .fields = (VMStateField[]) {
 524         VMSTATE_UINT32_ARRAY(r, CadenceUARTState, CADENCE_UART_R_MAX),
 525         VMSTATE_UINT8_ARRAY(rx_fifo, CadenceUARTState,
 526                             CADENCE_UART_RX_FIFO_SIZE),
 527         VMSTATE_UINT8_ARRAY(tx_fifo, CadenceUARTState,
 528                             CADENCE_UART_TX_FIFO_SIZE),
 529         VMSTATE_UINT32(rx_count, CadenceUARTState),
 530         VMSTATE_UINT32(tx_count, CadenceUARTState),
 531         VMSTATE_UINT32(rx_wpos, CadenceUARTState),
 532         VMSTATE_TIMER_PTR(fifo_trigger_handle, CadenceUARTState),
 533         VMSTATE_END_OF_LIST()
 534     }
 535 };
 536
 537 static Property cadence_uart_properties[] = {
 538     DEFINE_PROP_CHR("chardev", CadenceUARTState, chr),
 539     DEFINE_PROP_END_OF_LIST(),
 540 };
 541
 542 static void cadence_uart_class_init(ObjectClass *klass, void *data)
 543 {
 544     DeviceClass *dc = DEVICE_CLASS(klass);
 545
 546     dc->realize = cadence_uart_realize;
 547     dc->vmsd = &vmstate_cadence_uart;
 548     dc->reset = cadence_uart_reset;
 549     dc->props = cadence_uart_properties;
 550   }
 551
 552 static const TypeInfo cadence_uart_info = {
 553     .name          = TYPE_CADENCE_UART,
 554     .parent        = TYPE_SYS_BUS_DEVICE,
 555     .instance_size = sizeof(CadenceUARTState),
 556     .instance_init = cadence_uart_init,
 557     .class_init    = cadence_uart_class_init,
 558 };
 559
 560 static void cadence_uart_register_types(void)
 561 {
 562     type_register_static(&cadence_uart_info);
 563 }
 564
 565 type_init(cadence_uart_register_types)