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