hw/char/serial.c

   1 /*
   2  * QEMU 16550A UART emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  * Copyright (c) 2008 Citrix Systems, Inc.
   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/char/serial.h"
  28 #include "chardev/char-serial.h"
  29 #include "qapi/error.h"
  30 #include "qemu/timer.h"
  31 #include "qemu/error-report.h"
  32 #include "trace.h"
  33
  34 //#define DEBUG_SERIAL
  35
  36 #define UART_LCR_DLAB   0x80    /* Divisor latch access bit */
  37
  38 #define UART_IER_MSI    0x08    /* Enable Modem status interrupt */
  39 #define UART_IER_RLSI   0x04    /* Enable receiver line status interrupt */
  40 #define UART_IER_THRI   0x02    /* Enable Transmitter holding register int. */
  41 #define UART_IER_RDI    0x01    /* Enable receiver data interrupt */
  42
  43 #define UART_IIR_NO_INT 0x01    /* No interrupts pending */
  44 #define UART_IIR_ID     0x06    /* Mask for the interrupt ID */
  45
  46 #define UART_IIR_MSI    0x00    /* Modem status interrupt */
  47 #define UART_IIR_THRI   0x02    /* Transmitter holding register empty */
  48 #define UART_IIR_RDI    0x04    /* Receiver data interrupt */
  49 #define UART_IIR_RLSI   0x06    /* Receiver line status interrupt */
  50 #define UART_IIR_CTI    0x0C    /* Character Timeout Indication */
  51
  52 #define UART_IIR_FENF   0x80    /* Fifo enabled, but not functionning */
  53 #define UART_IIR_FE     0xC0    /* Fifo enabled */
  54
  55 /*
  56  * These are the definitions for the Modem Control Register
  57  */
  58 #define UART_MCR_LOOP   0x10    /* Enable loopback test mode */
  59 #define UART_MCR_OUT2   0x08    /* Out2 complement */
  60 #define UART_MCR_OUT1   0x04    /* Out1 complement */
  61 #define UART_MCR_RTS    0x02    /* RTS complement */
  62 #define UART_MCR_DTR    0x01    /* DTR complement */
  63
  64 /*
  65  * These are the definitions for the Modem Status Register
  66  */
  67 #define UART_MSR_DCD    0x80    /* Data Carrier Detect */
  68 #define UART_MSR_RI     0x40    /* Ring Indicator */
  69 #define UART_MSR_DSR    0x20    /* Data Set Ready */
  70 #define UART_MSR_CTS    0x10    /* Clear to Send */
  71 #define UART_MSR_DDCD   0x08    /* Delta DCD */
  72 #define UART_MSR_TERI   0x04    /* Trailing edge ring indicator */
  73 #define UART_MSR_DDSR   0x02    /* Delta DSR */
  74 #define UART_MSR_DCTS   0x01    /* Delta CTS */
  75 #define UART_MSR_ANY_DELTA 0x0F /* Any of the delta bits! */
  76
  77 #define UART_LSR_TEMT   0x40    /* Transmitter empty */
  78 #define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
  79 #define UART_LSR_BI     0x10    /* Break interrupt indicator */
  80 #define UART_LSR_FE     0x08    /* Frame error indicator */
  81 #define UART_LSR_PE     0x04    /* Parity error indicator */
  82 #define UART_LSR_OE     0x02    /* Overrun error indicator */
  83 #define UART_LSR_DR     0x01    /* Receiver data ready */
  84 #define UART_LSR_INT_ANY 0x1E   /* Any of the lsr-interrupt-triggering status bits */
  85
  86 /* Interrupt trigger levels. The byte-counts are for 16550A - in newer UARTs the byte-count for each ITL is higher. */
  87
  88 #define UART_FCR_ITL_1      0x00 /* 1 byte ITL */
  89 #define UART_FCR_ITL_2      0x40 /* 4 bytes ITL */
  90 #define UART_FCR_ITL_3      0x80 /* 8 bytes ITL */
  91 #define UART_FCR_ITL_4      0xC0 /* 14 bytes ITL */
  92
  93 #define UART_FCR_DMS        0x08    /* DMA Mode Select */
  94 #define UART_FCR_XFR        0x04    /* XMIT Fifo Reset */
  95 #define UART_FCR_RFR        0x02    /* RCVR Fifo Reset */
  96 #define UART_FCR_FE         0x01    /* FIFO Enable */
  97
  98 #define MAX_XMIT_RETRY      4
  99
 100 #ifdef DEBUG_SERIAL
 101 #define DPRINTF(fmt, ...) \
 102 do { fprintf(stderr, "serial: " fmt , ## __VA_ARGS__); } while (0)
 103 #else
 104 #define DPRINTF(fmt, ...) \
 105 do {} while (0)
 106 #endif
 107
 108 static void serial_receive1(void *opaque, const uint8_t *buf, int size);
 109 static void serial_xmit(SerialState *s);
 110
 111 static inline void recv_fifo_put(SerialState *s, uint8_t chr)
 112 {
 113     /* Receive overruns do not overwrite FIFO contents. */
 114     if (!fifo8_is_full(&s->recv_fifo)) {
 115         fifo8_push(&s->recv_fifo, chr);
 116     } else {
 117         s->lsr |= UART_LSR_OE;
 118     }
 119 }
 120
 121 static void serial_update_irq(SerialState *s)
 122 {
 123     uint8_t tmp_iir = UART_IIR_NO_INT;
 124
 125     if ((s->ier & UART_IER_RLSI) && (s->lsr & UART_LSR_INT_ANY)) {
 126         tmp_iir = UART_IIR_RLSI;
 127     } else if ((s->ier & UART_IER_RDI) && s->timeout_ipending) {
 128         /* Note that(s->ier & UART_IER_RDI) can mask this interrupt,
 129          * this is not in the specification but is observed on existing
 130          * hardware.  */
 131         tmp_iir = UART_IIR_CTI;
 132     } else if ((s->ier & UART_IER_RDI) && (s->lsr & UART_LSR_DR) &&
 133                (!(s->fcr & UART_FCR_FE) ||
 134                 s->recv_fifo.num >= s->recv_fifo_itl)) {
 135         tmp_iir = UART_IIR_RDI;
 136     } else if ((s->ier & UART_IER_THRI) && s->thr_ipending) {
 137         tmp_iir = UART_IIR_THRI;
 138     } else if ((s->ier & UART_IER_MSI) && (s->msr & UART_MSR_ANY_DELTA)) {
 139         tmp_iir = UART_IIR_MSI;
 140     }
 141
 142     s->iir = tmp_iir | (s->iir & 0xF0);
 143
 144     if (tmp_iir != UART_IIR_NO_INT) {
 145         qemu_irq_raise(s->irq);
 146     } else {
 147         qemu_irq_lower(s->irq);
 148     }
 149 }
 150
 151 static void serial_update_parameters(SerialState *s)
 152 {
 153     float speed;
 154     int parity, data_bits, stop_bits, frame_size;
 155     QEMUSerialSetParams ssp;
 156
 157     /* Start bit. */
 158     frame_size = 1;
 159     if (s->lcr & 0x08) {
 160         /* Parity bit. */
 161         frame_size++;
 162         if (s->lcr & 0x10)
 163             parity = 'E';
 164         else
 165             parity = 'O';
 166     } else {
 167             parity = 'N';
 168     }
 169     if (s->lcr & 0x04) {
 170         stop_bits = 2;
 171     } else {
 172         stop_bits = 1;
 173     }
 174
 175     data_bits = (s->lcr & 0x03) + 5;
 176     frame_size += data_bits + stop_bits;
 177     /* Zero divisor should give about 3500 baud */
 178     speed = (s->divider == 0) ? 3500 : (float) s->baudbase / s->divider;
 179     ssp.speed = speed;
 180     ssp.parity = parity;
 181     ssp.data_bits = data_bits;
 182     ssp.stop_bits = stop_bits;
 183     s->char_transmit_time =  (NANOSECONDS_PER_SECOND / speed) * frame_size;
 184     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 185
 186     DPRINTF("speed=%.2f parity=%c data=%d stop=%d\n",
 187            speed, parity, data_bits, stop_bits);
 188 }
 189
 190 static void serial_update_msl(SerialState *s)
 191 {
 192     uint8_t omsr;
 193     int flags;
 194
 195     timer_del(s->modem_status_poll);
 196
 197     if (qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_GET_TIOCM,
 198                           &flags) == -ENOTSUP) {
 199         s->poll_msl = -1;
 200         return;
 201     }
 202
 203     omsr = s->msr;
 204
 205     s->msr = (flags & CHR_TIOCM_CTS) ? s->msr | UART_MSR_CTS : s->msr & ~UART_MSR_CTS;
 206     s->msr = (flags & CHR_TIOCM_DSR) ? s->msr | UART_MSR_DSR : s->msr & ~UART_MSR_DSR;
 207     s->msr = (flags & CHR_TIOCM_CAR) ? s->msr | UART_MSR_DCD : s->msr & ~UART_MSR_DCD;
 208     s->msr = (flags & CHR_TIOCM_RI) ? s->msr | UART_MSR_RI : s->msr & ~UART_MSR_RI;
 209
 210     if (s->msr != omsr) {
 211          /* Set delta bits */
 212          s->msr = s->msr | ((s->msr >> 4) ^ (omsr >> 4));
 213          /* UART_MSR_TERI only if change was from 1 -> 0 */
 214          if ((s->msr & UART_MSR_TERI) && !(omsr & UART_MSR_RI))
 215              s->msr &= ~UART_MSR_TERI;
 216          serial_update_irq(s);
 217     }
 218
 219     /* The real 16550A apparently has a 250ns response latency to line status changes.
 220        We'll be lazy and poll only every 10ms, and only poll it at all if MSI interrupts are turned on */
 221
 222     if (s->poll_msl) {
 223         timer_mod(s->modem_status_poll, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
 224                   NANOSECONDS_PER_SECOND / 100);
 225     }
 226 }
 227
 228 static gboolean serial_watch_cb(GIOChannel *chan, GIOCondition cond,
 229                                 void *opaque)
 230 {
 231     SerialState *s = opaque;
 232     s->watch_tag = 0;
 233     serial_xmit(s);
 234     return FALSE;
 235 }
 236
 237 static void serial_xmit(SerialState *s)
 238 {
 239     do {
 240         assert(!(s->lsr & UART_LSR_TEMT));
 241         if (s->tsr_retry == 0) {
 242             assert(!(s->lsr & UART_LSR_THRE));
 243
 244             if (s->fcr & UART_FCR_FE) {
 245                 assert(!fifo8_is_empty(&s->xmit_fifo));
 246                 s->tsr = fifo8_pop(&s->xmit_fifo);
 247                 if (!s->xmit_fifo.num) {
 248                     s->lsr |= UART_LSR_THRE;
 249                 }
 250             } else {
 251                 s->tsr = s->thr;
 252                 s->lsr |= UART_LSR_THRE;
 253             }
 254             if ((s->lsr & UART_LSR_THRE) && !s->thr_ipending) {
 255                 s->thr_ipending = 1;
 256                 serial_update_irq(s);
 257             }
 258         }
 259
 260         if (s->mcr & UART_MCR_LOOP) {
 261             /* in loopback mode, say that we just received a char */
 262             serial_receive1(s, &s->tsr, 1);
 263         } else {
 264             int rc = qemu_chr_fe_write(&s->chr, &s->tsr, 1);
 265
 266             if ((rc == 0 ||
 267                  (rc == -1 && errno == EAGAIN)) &&
 268                 s->tsr_retry < MAX_XMIT_RETRY) {
 269                 assert(s->watch_tag == 0);
 270                 s->watch_tag =
 271                     qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 272                                           serial_watch_cb, s);
 273                 if (s->watch_tag > 0) {
 274                     s->tsr_retry++;
 275                     return;
 276                 }
 277             }
 278         }
 279         s->tsr_retry = 0;
 280
 281         /* Transmit another byte if it is already available. It is only
 282            possible when FIFO is enabled and not empty. */
 283     } while (!(s->lsr & UART_LSR_THRE));
 284
 285     s->last_xmit_ts = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 286     s->lsr |= UART_LSR_TEMT;
 287 }
 288
 289 /* Setter for FCR.
 290    is_load flag means, that value is set while loading VM state
 291    and interrupt should not be invoked */
 292 static void serial_write_fcr(SerialState *s, uint8_t val)
 293 {
 294     /* Set fcr - val only has the bits that are supposed to "stick" */
 295     s->fcr = val;
 296
 297     if (val & UART_FCR_FE) {
 298         s->iir |= UART_IIR_FE;
 299         /* Set recv_fifo trigger Level */
 300         switch (val & 0xC0) {
 301         case UART_FCR_ITL_1:
 302             s->recv_fifo_itl = 1;
 303             break;
 304         case UART_FCR_ITL_2:
 305             s->recv_fifo_itl = 4;
 306             break;
 307         case UART_FCR_ITL_3:
 308             s->recv_fifo_itl = 8;
 309             break;
 310         case UART_FCR_ITL_4:
 311             s->recv_fifo_itl = 14;
 312             break;
 313         }
 314     } else {
 315         s->iir &= ~UART_IIR_FE;
 316     }
 317 }
 318
 319 static void serial_update_tiocm(SerialState *s)
 320 {
 321     int flags;
 322
 323     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_GET_TIOCM, &flags);
 324
 325     flags &= ~(CHR_TIOCM_RTS | CHR_TIOCM_DTR);
 326
 327     if (s->mcr & UART_MCR_RTS) {
 328         flags |= CHR_TIOCM_RTS;
 329     }
 330     if (s->mcr & UART_MCR_DTR) {
 331         flags |= CHR_TIOCM_DTR;
 332     }
 333
 334     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_TIOCM, &flags);
 335 }
 336
 337 static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
 338                                 unsigned size)
 339 {
 340     SerialState *s = opaque;
 341
 342     addr &= 7;
 343     trace_serial_ioport_write(addr, val);
 344     switch(addr) {
 345     default:
 346     case 0:
 347         if (s->lcr & UART_LCR_DLAB) {
 348             if (size == 1) {
 349                 s->divider = (s->divider & 0xff00) | val;
 350             } else {
 351                 s->divider = val;
 352             }
 353             serial_update_parameters(s);
 354         } else {
 355             s->thr = (uint8_t) val;
 356             if(s->fcr & UART_FCR_FE) {
 357                 /* xmit overruns overwrite data, so make space if needed */
 358                 if (fifo8_is_full(&s->xmit_fifo)) {
 359                     fifo8_pop(&s->xmit_fifo);
 360                 }
 361                 fifo8_push(&s->xmit_fifo, s->thr);
 362             }
 363             s->thr_ipending = 0;
 364             s->lsr &= ~UART_LSR_THRE;
 365             s->lsr &= ~UART_LSR_TEMT;
 366             serial_update_irq(s);
 367             if (s->tsr_retry == 0) {
 368                 serial_xmit(s);
 369             }
 370         }
 371         break;
 372     case 1:
 373         if (s->lcr & UART_LCR_DLAB) {
 374             s->divider = (s->divider & 0x00ff) | (val << 8);
 375             serial_update_parameters(s);
 376         } else {
 377             uint8_t changed = (s->ier ^ val) & 0x0f;
 378             s->ier = val & 0x0f;
 379             /* If the backend device is a real serial port, turn polling of the modem
 380              * status lines on physical port on or off depending on UART_IER_MSI state.
 381              */
 382             if ((changed & UART_IER_MSI) && s->poll_msl >= 0) {
 383                 if (s->ier & UART_IER_MSI) {
 384                      s->poll_msl = 1;
 385                      serial_update_msl(s);
 386                 } else {
 387                      timer_del(s->modem_status_poll);
 388                      s->poll_msl = 0;
 389                 }
 390             }
 391
 392             /* Turning on the THRE interrupt on IER can trigger the interrupt
 393              * if LSR.THRE=1, even if it had been masked before by reading IIR.
 394              * This is not in the datasheet, but Windows relies on it.  It is
 395              * unclear if THRE has to be resampled every time THRI becomes
 396              * 1, or only on the rising edge.  Bochs does the latter, and Windows
 397              * always toggles IER to all zeroes and back to all ones, so do the
 398              * same.
 399              *
 400              * If IER.THRI is zero, thr_ipending is not used.  Set it to zero
 401              * so that the thr_ipending subsection is not migrated.
 402              */
 403             if (changed & UART_IER_THRI) {
 404                 if ((s->ier & UART_IER_THRI) && (s->lsr & UART_LSR_THRE)) {
 405                     s->thr_ipending = 1;
 406                 } else {
 407                     s->thr_ipending = 0;
 408                 }
 409             }
 410
 411             if (changed) {
 412                 serial_update_irq(s);
 413             }
 414         }
 415         break;
 416     case 2:
 417         /* Did the enable/disable flag change? If so, make sure FIFOs get flushed */
 418         if ((val ^ s->fcr) & UART_FCR_FE) {
 419             val |= UART_FCR_XFR | UART_FCR_RFR;
 420         }
 421
 422         /* FIFO clear */
 423
 424         if (val & UART_FCR_RFR) {
 425             s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 426             timer_del(s->fifo_timeout_timer);
 427             s->timeout_ipending = 0;
 428             fifo8_reset(&s->recv_fifo);
 429         }
 430
 431         if (val & UART_FCR_XFR) {
 432             s->lsr |= UART_LSR_THRE;
 433             s->thr_ipending = 1;
 434             fifo8_reset(&s->xmit_fifo);
 435         }
 436
 437         serial_write_fcr(s, val & 0xC9);
 438         serial_update_irq(s);
 439         break;
 440     case 3:
 441         {
 442             int break_enable;
 443             s->lcr = val;
 444             serial_update_parameters(s);
 445             break_enable = (val >> 6) & 1;
 446             if (break_enable != s->last_break_enable) {
 447                 s->last_break_enable = break_enable;
 448                 qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 449                                   &break_enable);
 450             }
 451         }
 452         break;
 453     case 4:
 454         {
 455             int old_mcr = s->mcr;
 456             s->mcr = val & 0x1f;
 457             if (val & UART_MCR_LOOP)
 458                 break;
 459
 460             if (s->poll_msl >= 0 && old_mcr != s->mcr) {
 461                 serial_update_tiocm(s);
 462                 /* Update the modem status after a one-character-send wait-time, since there may be a response
 463                    from the device/computer at the other end of the serial line */
 464                 timer_mod(s->modem_status_poll, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time);
 465             }
 466         }
 467         break;
 468     case 5:
 469         break;
 470     case 6:
 471         break;
 472     case 7:
 473         s->scr = val;
 474         break;
 475     }
 476 }
 477
 478 static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size)
 479 {
 480     SerialState *s = opaque;
 481     uint32_t ret;
 482
 483     addr &= 7;
 484     switch(addr) {
 485     default:
 486     case 0:
 487         if (s->lcr & UART_LCR_DLAB) {
 488             ret = s->divider & 0xff;
 489         } else {
 490             if(s->fcr & UART_FCR_FE) {
 491                 ret = fifo8_is_empty(&s->recv_fifo) ?
 492                             0 : fifo8_pop(&s->recv_fifo);
 493                 if (s->recv_fifo.num == 0) {
 494                     s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 495                 } else {
 496                     timer_mod(s->fifo_timeout_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time * 4);
 497                 }
 498                 s->timeout_ipending = 0;
 499             } else {
 500                 ret = s->rbr;
 501                 s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 502             }
 503             serial_update_irq(s);
 504             if (!(s->mcr & UART_MCR_LOOP)) {
 505                 /* in loopback mode, don't receive any data */
 506                 qemu_chr_fe_accept_input(&s->chr);
 507             }
 508         }
 509         break;
 510     case 1:
 511         if (s->lcr & UART_LCR_DLAB) {
 512             ret = (s->divider >> 8) & 0xff;
 513         } else {
 514             ret = s->ier;
 515         }
 516         break;
 517     case 2:
 518         ret = s->iir;
 519         if ((ret & UART_IIR_ID) == UART_IIR_THRI) {
 520             s->thr_ipending = 0;
 521             serial_update_irq(s);
 522         }
 523         break;
 524     case 3:
 525         ret = s->lcr;
 526         break;
 527     case 4:
 528         ret = s->mcr;
 529         break;
 530     case 5:
 531         ret = s->lsr;
 532         /* Clear break and overrun interrupts */
 533         if (s->lsr & (UART_LSR_BI|UART_LSR_OE)) {
 534             s->lsr &= ~(UART_LSR_BI|UART_LSR_OE);
 535             serial_update_irq(s);
 536         }
 537         break;
 538     case 6:
 539         if (s->mcr & UART_MCR_LOOP) {
 540             /* in loopback, the modem output pins are connected to the
 541                inputs */
 542             ret = (s->mcr & 0x0c) << 4;
 543             ret |= (s->mcr & 0x02) << 3;
 544             ret |= (s->mcr & 0x01) << 5;
 545         } else {
 546             if (s->poll_msl >= 0)
 547                 serial_update_msl(s);
 548             ret = s->msr;
 549             /* Clear delta bits & msr int after read, if they were set */
 550             if (s->msr & UART_MSR_ANY_DELTA) {
 551                 s->msr &= 0xF0;
 552                 serial_update_irq(s);
 553             }
 554         }
 555         break;
 556     case 7:
 557         ret = s->scr;
 558         break;
 559     }
 560     trace_serial_ioport_read(addr, ret);
 561     return ret;
 562 }
 563
 564 static int serial_can_receive(SerialState *s)
 565 {
 566     if(s->fcr & UART_FCR_FE) {
 567         if (s->recv_fifo.num < UART_FIFO_LENGTH) {
 568             /*
 569              * Advertise (fifo.itl - fifo.count) bytes when count < ITL, and 1
 570              * if above. If UART_FIFO_LENGTH - fifo.count is advertised the
 571              * effect will be to almost always fill the fifo completely before
 572              * the guest has a chance to respond, effectively overriding the ITL
 573              * that the guest has set.
 574              */
 575             return (s->recv_fifo.num <= s->recv_fifo_itl) ?
 576                         s->recv_fifo_itl - s->recv_fifo.num : 1;
 577         } else {
 578             return 0;
 579         }
 580     } else {
 581         return !(s->lsr & UART_LSR_DR);
 582     }
 583 }
 584
 585 static void serial_receive_break(SerialState *s)
 586 {
 587     s->rbr = 0;
 588     /* When the LSR_DR is set a null byte is pushed into the fifo */
 589     recv_fifo_put(s, '\0');
 590     s->lsr |= UART_LSR_BI | UART_LSR_DR;
 591     serial_update_irq(s);
 592 }
 593
 594 /* There's data in recv_fifo and s->rbr has not been read for 4 char transmit times */
 595 static void fifo_timeout_int (void *opaque) {
 596     SerialState *s = opaque;
 597     if (s->recv_fifo.num) {
 598         s->timeout_ipending = 1;
 599         serial_update_irq(s);
 600     }
 601 }
 602
 603 static int serial_can_receive1(void *opaque)
 604 {
 605     SerialState *s = opaque;
 606     return serial_can_receive(s);
 607 }
 608
 609 static void serial_receive1(void *opaque, const uint8_t *buf, int size)
 610 {
 611     SerialState *s = opaque;
 612
 613     if (s->wakeup) {
 614         qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
 615     }
 616     if(s->fcr & UART_FCR_FE) {
 617         int i;
 618         for (i = 0; i < size; i++) {
 619             recv_fifo_put(s, buf[i]);
 620         }
 621         s->lsr |= UART_LSR_DR;
 622         /* call the timeout receive callback in 4 char transmit time */
 623         timer_mod(s->fifo_timeout_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time * 4);
 624     } else {
 625         if (s->lsr & UART_LSR_DR)
 626             s->lsr |= UART_LSR_OE;
 627         s->rbr = buf[0];
 628         s->lsr |= UART_LSR_DR;
 629     }
 630     serial_update_irq(s);
 631 }
 632
 633 static void serial_event(void *opaque, int event)
 634 {
 635     SerialState *s = opaque;
 636     DPRINTF("event %x\n", event);
 637     if (event == CHR_EVENT_BREAK)
 638         serial_receive_break(s);
 639 }
 640
 641 static int serial_pre_save(void *opaque)
 642 {
 643     SerialState *s = opaque;
 644     s->fcr_vmstate = s->fcr;
 645
 646     return 0;
 647 }
 648
 649 static int serial_pre_load(void *opaque)
 650 {
 651     SerialState *s = opaque;
 652     s->thr_ipending = -1;
 653     s->poll_msl = -1;
 654     return 0;
 655 }
 656
 657 static int serial_post_load(void *opaque, int version_id)
 658 {
 659     SerialState *s = opaque;
 660
 661     if (version_id < 3) {
 662         s->fcr_vmstate = 0;
 663     }
 664     if (s->thr_ipending == -1) {
 665         s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
 666     }
 667
 668     if (s->tsr_retry > 0) {
 669         /* tsr_retry > 0 implies LSR.TEMT = 0 (transmitter not empty).  */
 670         if (s->lsr & UART_LSR_TEMT) {
 671             error_report("inconsistent state in serial device "
 672                          "(tsr empty, tsr_retry=%d", s->tsr_retry);
 673             return -1;
 674         }
 675
 676         if (s->tsr_retry > MAX_XMIT_RETRY) {
 677             s->tsr_retry = MAX_XMIT_RETRY;
 678         }
 679
 680         assert(s->watch_tag == 0);
 681         s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 682                                              serial_watch_cb, s);
 683     } else {
 684         /* tsr_retry == 0 implies LSR.TEMT = 1 (transmitter empty).  */
 685         if (!(s->lsr & UART_LSR_TEMT)) {
 686             error_report("inconsistent state in serial device "
 687                          "(tsr not empty, tsr_retry=0");
 688             return -1;
 689         }
 690     }
 691
 692     s->last_break_enable = (s->lcr >> 6) & 1;
 693     /* Initialize fcr via setter to perform essential side-effects */
 694     serial_write_fcr(s, s->fcr_vmstate);
 695     serial_update_parameters(s);
 696     return 0;
 697 }
 698
 699 static bool serial_thr_ipending_needed(void *opaque)
 700 {
 701     SerialState *s = opaque;
 702
 703     if (s->ier & UART_IER_THRI) {
 704         bool expected_value = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
 705         return s->thr_ipending != expected_value;
 706     } else {
 707         /* LSR.THRE will be sampled again when the interrupt is
 708          * enabled.  thr_ipending is not used in this case, do
 709          * not migrate it.
 710          */
 711         return false;
 712     }
 713 }
 714
 715 static const VMStateDescription vmstate_serial_thr_ipending = {
 716     .name = "serial/thr_ipending",
 717     .version_id = 1,
 718     .minimum_version_id = 1,
 719     .needed = serial_thr_ipending_needed,
 720     .fields = (VMStateField[]) {
 721         VMSTATE_INT32(thr_ipending, SerialState),
 722         VMSTATE_END_OF_LIST()
 723     }
 724 };
 725
 726 static bool serial_tsr_needed(void *opaque)
 727 {
 728     SerialState *s = (SerialState *)opaque;
 729     return s->tsr_retry != 0;
 730 }
 731
 732 static const VMStateDescription vmstate_serial_tsr = {
 733     .name = "serial/tsr",
 734     .version_id = 1,
 735     .minimum_version_id = 1,
 736     .needed = serial_tsr_needed,
 737     .fields = (VMStateField[]) {
 738         VMSTATE_UINT32(tsr_retry, SerialState),
 739         VMSTATE_UINT8(thr, SerialState),
 740         VMSTATE_UINT8(tsr, SerialState),
 741         VMSTATE_END_OF_LIST()
 742     }
 743 };
 744
 745 static bool serial_recv_fifo_needed(void *opaque)
 746 {
 747     SerialState *s = (SerialState *)opaque;
 748     return !fifo8_is_empty(&s->recv_fifo);
 749
 750 }
 751
 752 static const VMStateDescription vmstate_serial_recv_fifo = {
 753     .name = "serial/recv_fifo",
 754     .version_id = 1,
 755     .minimum_version_id = 1,
 756     .needed = serial_recv_fifo_needed,
 757     .fields = (VMStateField[]) {
 758         VMSTATE_STRUCT(recv_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
 759         VMSTATE_END_OF_LIST()
 760     }
 761 };
 762
 763 static bool serial_xmit_fifo_needed(void *opaque)
 764 {
 765     SerialState *s = (SerialState *)opaque;
 766     return !fifo8_is_empty(&s->xmit_fifo);
 767 }
 768
 769 static const VMStateDescription vmstate_serial_xmit_fifo = {
 770     .name = "serial/xmit_fifo",
 771     .version_id = 1,
 772     .minimum_version_id = 1,
 773     .needed = serial_xmit_fifo_needed,
 774     .fields = (VMStateField[]) {
 775         VMSTATE_STRUCT(xmit_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
 776         VMSTATE_END_OF_LIST()
 777     }
 778 };
 779
 780 static bool serial_fifo_timeout_timer_needed(void *opaque)
 781 {
 782     SerialState *s = (SerialState *)opaque;
 783     return timer_pending(s->fifo_timeout_timer);
 784 }
 785
 786 static const VMStateDescription vmstate_serial_fifo_timeout_timer = {
 787     .name = "serial/fifo_timeout_timer",
 788     .version_id = 1,
 789     .minimum_version_id = 1,
 790     .needed = serial_fifo_timeout_timer_needed,
 791     .fields = (VMStateField[]) {
 792         VMSTATE_TIMER_PTR(fifo_timeout_timer, SerialState),
 793         VMSTATE_END_OF_LIST()
 794     }
 795 };
 796
 797 static bool serial_timeout_ipending_needed(void *opaque)
 798 {
 799     SerialState *s = (SerialState *)opaque;
 800     return s->timeout_ipending != 0;
 801 }
 802
 803 static const VMStateDescription vmstate_serial_timeout_ipending = {
 804     .name = "serial/timeout_ipending",
 805     .version_id = 1,
 806     .minimum_version_id = 1,
 807     .needed = serial_timeout_ipending_needed,
 808     .fields = (VMStateField[]) {
 809         VMSTATE_INT32(timeout_ipending, SerialState),
 810         VMSTATE_END_OF_LIST()
 811     }
 812 };
 813
 814 static bool serial_poll_needed(void *opaque)
 815 {
 816     SerialState *s = (SerialState *)opaque;
 817     return s->poll_msl >= 0;
 818 }
 819
 820 static const VMStateDescription vmstate_serial_poll = {
 821     .name = "serial/poll",
 822     .version_id = 1,
 823     .needed = serial_poll_needed,
 824     .minimum_version_id = 1,
 825     .fields = (VMStateField[]) {
 826         VMSTATE_INT32(poll_msl, SerialState),
 827         VMSTATE_TIMER_PTR(modem_status_poll, SerialState),
 828         VMSTATE_END_OF_LIST()
 829     }
 830 };
 831
 832 const VMStateDescription vmstate_serial = {
 833     .name = "serial",
 834     .version_id = 3,
 835     .minimum_version_id = 2,
 836     .pre_save = serial_pre_save,
 837     .pre_load = serial_pre_load,
 838     .post_load = serial_post_load,
 839     .fields = (VMStateField[]) {
 840         VMSTATE_UINT16_V(divider, SerialState, 2),
 841         VMSTATE_UINT8(rbr, SerialState),
 842         VMSTATE_UINT8(ier, SerialState),
 843         VMSTATE_UINT8(iir, SerialState),
 844         VMSTATE_UINT8(lcr, SerialState),
 845         VMSTATE_UINT8(mcr, SerialState),
 846         VMSTATE_UINT8(lsr, SerialState),
 847         VMSTATE_UINT8(msr, SerialState),
 848         VMSTATE_UINT8(scr, SerialState),
 849         VMSTATE_UINT8_V(fcr_vmstate, SerialState, 3),
 850         VMSTATE_END_OF_LIST()
 851     },
 852     .subsections = (const VMStateDescription*[]) {
 853         &vmstate_serial_thr_ipending,
 854         &vmstate_serial_tsr,
 855         &vmstate_serial_recv_fifo,
 856         &vmstate_serial_xmit_fifo,
 857         &vmstate_serial_fifo_timeout_timer,
 858         &vmstate_serial_timeout_ipending,
 859         &vmstate_serial_poll,
 860         NULL
 861     }
 862 };
 863
 864 static void serial_reset(void *opaque)
 865 {
 866     SerialState *s = opaque;
 867
 868     if (s->watch_tag > 0) {
 869         g_source_remove(s->watch_tag);
 870         s->watch_tag = 0;
 871     }
 872
 873     s->rbr = 0;
 874     s->ier = 0;
 875     s->iir = UART_IIR_NO_INT;
 876     s->lcr = 0;
 877     s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
 878     s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
 879     /* Default to 9600 baud, 1 start bit, 8 data bits, 1 stop bit, no parity. */
 880     s->divider = 0x0C;
 881     s->mcr = UART_MCR_OUT2;
 882     s->scr = 0;
 883     s->tsr_retry = 0;
 884     s->char_transmit_time = (NANOSECONDS_PER_SECOND / 9600) * 10;
 885     s->poll_msl = 0;
 886
 887     s->timeout_ipending = 0;
 888     timer_del(s->fifo_timeout_timer);
 889     timer_del(s->modem_status_poll);
 890
 891     fifo8_reset(&s->recv_fifo);
 892     fifo8_reset(&s->xmit_fifo);
 893
 894     s->last_xmit_ts = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 895
 896     s->thr_ipending = 0;
 897     s->last_break_enable = 0;
 898     qemu_irq_lower(s->irq);
 899
 900     serial_update_msl(s);
 901     s->msr &= ~UART_MSR_ANY_DELTA;
 902 }
 903
 904 static int serial_be_change(void *opaque)
 905 {
 906     SerialState *s = opaque;
 907
 908     qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1,
 909                              serial_event, serial_be_change, s, NULL, true);
 910
 911     serial_update_parameters(s);
 912
 913     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 914                       &s->last_break_enable);
 915
 916     s->poll_msl = (s->ier & UART_IER_MSI) ? 1 : 0;
 917     serial_update_msl(s);
 918
 919     if (s->poll_msl >= 0 && !(s->mcr & UART_MCR_LOOP)) {
 920         serial_update_tiocm(s);
 921     }
 922
 923     if (s->watch_tag > 0) {
 924         g_source_remove(s->watch_tag);
 925         s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 926                                              serial_watch_cb, s);
 927     }
 928
 929     return 0;
 930 }
 931
 932 void serial_realize_core(SerialState *s, Error **errp)
 933 {
 934     s->modem_status_poll = timer_new_ns(QEMU_CLOCK_VIRTUAL, (QEMUTimerCB *) serial_update_msl, s);
 935
 936     s->fifo_timeout_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, (QEMUTimerCB *) fifo_timeout_int, s);
 937     qemu_register_reset(serial_reset, s);
 938
 939     qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1,
 940                              serial_event, serial_be_change, s, NULL, true);
 941     fifo8_create(&s->recv_fifo, UART_FIFO_LENGTH);
 942     fifo8_create(&s->xmit_fifo, UART_FIFO_LENGTH);
 943     serial_reset(s);
 944 }
 945
 946 void serial_exit_core(SerialState *s)
 947 {
 948     qemu_chr_fe_deinit(&s->chr, false);
 949
 950     timer_del(s->modem_status_poll);
 951     timer_free(s->modem_status_poll);
 952
 953     timer_del(s->fifo_timeout_timer);
 954     timer_free(s->fifo_timeout_timer);
 955
 956     fifo8_destroy(&s->recv_fifo);
 957     fifo8_destroy(&s->xmit_fifo);
 958
 959     qemu_unregister_reset(serial_reset, s);
 960 }
 961
 962 /* Change the main reference oscillator frequency. */
 963 void serial_set_frequency(SerialState *s, uint32_t frequency)
 964 {
 965     s->baudbase = frequency;
 966     serial_update_parameters(s);
 967 }
 968
 969 const MemoryRegionOps serial_io_ops = {
 970     .read = serial_ioport_read,
 971     .write = serial_ioport_write,
 972     .impl = {
 973         .min_access_size = 1,
 974         .max_access_size = 1,
 975     },
 976     .endianness = DEVICE_LITTLE_ENDIAN,
 977 };
 978
 979 SerialState *serial_init(int base, qemu_irq irq, int baudbase,
 980                          Chardev *chr, MemoryRegion *system_io)
 981 {
 982     SerialState *s;
 983
 984     s = g_malloc0(sizeof(SerialState));
 985
 986     s->irq = irq;
 987     s->baudbase = baudbase;
 988     qemu_chr_fe_init(&s->chr, chr, &error_abort);
 989     serial_realize_core(s, &error_fatal);
 990
 991     vmstate_register(NULL, base, &vmstate_serial, s);
 992
 993     memory_region_init_io(&s->io, NULL, &serial_io_ops, s, "serial", 8);
 994     memory_region_add_subregion(system_io, base, &s->io);
 995
 996     return s;
 997 }
 998
 999 /* Memory mapped interface */
1000 static uint64_t serial_mm_read(void *opaque, hwaddr addr,
1001                                unsigned size)
1002 {
1003     SerialState *s = opaque;
1004     return serial_ioport_read(s, addr >> s->it_shift, 1);
1005 }
1006
1007 static void serial_mm_write(void *opaque, hwaddr addr,
1008                             uint64_t value, unsigned size)
1009 {
1010     SerialState *s = opaque;
1011     value &= 255;
1012     serial_ioport_write(s, addr >> s->it_shift, value, 1);
1013 }
1014
1015 static const MemoryRegionOps serial_mm_ops[3] = {
1016     [DEVICE_NATIVE_ENDIAN] = {
1017         .read = serial_mm_read,
1018         .write = serial_mm_write,
1019         .endianness = DEVICE_NATIVE_ENDIAN,
1020         .valid.max_access_size = 8,
1021         .impl.max_access_size = 8,
1022     },
1023     [DEVICE_LITTLE_ENDIAN] = {
1024         .read = serial_mm_read,
1025         .write = serial_mm_write,
1026         .endianness = DEVICE_LITTLE_ENDIAN,
1027         .valid.max_access_size = 8,
1028         .impl.max_access_size = 8,
1029     },
1030     [DEVICE_BIG_ENDIAN] = {
1031         .read = serial_mm_read,
1032         .write = serial_mm_write,
1033         .endianness = DEVICE_BIG_ENDIAN,
1034         .valid.max_access_size = 8,
1035         .impl.max_access_size = 8,
1036     },
1037 };
1038
1039 SerialState *serial_mm_init(MemoryRegion *address_space,
1040                             hwaddr base, int it_shift,
1041                             qemu_irq irq, int baudbase,
1042                             Chardev *chr, enum device_endian end)
1043 {
1044     SerialState *s;
1045
1046     s = g_malloc0(sizeof(SerialState));
1047
1048     s->it_shift = it_shift;
1049     s->irq = irq;
1050     s->baudbase = baudbase;
1051     qemu_chr_fe_init(&s->chr, chr, &error_abort);
1052
1053     serial_realize_core(s, &error_fatal);
1054     vmstate_register(NULL, base, &vmstate_serial, s);
1055
1056     memory_region_init_io(&s->io, NULL, &serial_mm_ops[end], s,
1057                           "serial", 8 << it_shift);
1058     memory_region_add_subregion(address_space, base, &s->io);
1059     return s;
1060 }