hw/char/cadence_uart.c

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