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 "qemu/bitops.h"
  28 #include "hw/char/serial.h"
  29 #include "hw/irq.h"
  30 #include "migration/vmstate.h"
  31 #include "chardev/char-serial.h"
  32 #include "qapi/error.h"
  33 #include "qemu/timer.h"
  34 #include "sysemu/reset.h"
  35 #include "sysemu/runstate.h"
  36 #include "qemu/error-report.h"
  37 #include "trace.h"
  38 #include "hw/qdev-properties.h"
  39 #include "hw/qdev-properties-system.h"
  40
  41 #define UART_LCR_DLAB   0x80    /* Divisor latch access bit */
  42
  43 #define UART_IER_MSI    0x08    /* Enable Modem status interrupt */
  44 #define UART_IER_RLSI   0x04    /* Enable receiver line status interrupt */
  45 #define UART_IER_THRI   0x02    /* Enable Transmitter holding register int. */
  46 #define UART_IER_RDI    0x01    /* Enable receiver data interrupt */
  47
  48 #define UART_IIR_NO_INT 0x01    /* No interrupts pending */
  49 #define UART_IIR_ID     0x06    /* Mask for the interrupt ID */
  50
  51 #define UART_IIR_MSI    0x00    /* Modem status interrupt */
  52 #define UART_IIR_THRI   0x02    /* Transmitter holding register empty */
  53 #define UART_IIR_RDI    0x04    /* Receiver data interrupt */
  54 #define UART_IIR_RLSI   0x06    /* Receiver line status interrupt */
  55 #define UART_IIR_CTI    0x0C    /* Character Timeout Indication */
  56
  57 #define UART_IIR_FENF   0x80    /* Fifo enabled, but not functionning */
  58 #define UART_IIR_FE     0xC0    /* Fifo enabled */
  59
  60 /*
  61  * These are the definitions for the Modem Control Register
  62  */
  63 #define UART_MCR_LOOP   0x10    /* Enable loopback test mode */
  64 #define UART_MCR_OUT2   0x08    /* Out2 complement */
  65 #define UART_MCR_OUT1   0x04    /* Out1 complement */
  66 #define UART_MCR_RTS    0x02    /* RTS complement */
  67 #define UART_MCR_DTR    0x01    /* DTR complement */
  68
  69 /*
  70  * These are the definitions for the Modem Status Register
  71  */
  72 #define UART_MSR_DCD        0x80    /* Data Carrier Detect */
  73 #define UART_MSR_RI         0x40    /* Ring Indicator */
  74 #define UART_MSR_DSR        0x20    /* Data Set Ready */
  75 #define UART_MSR_CTS        0x10    /* Clear to Send */
  76 #define UART_MSR_DDCD       0x08    /* Delta DCD */
  77 #define UART_MSR_TERI       0x04    /* Trailing edge ring indicator */
  78 #define UART_MSR_DDSR       0x02    /* Delta DSR */
  79 #define UART_MSR_DCTS       0x01    /* Delta CTS */
  80 #define UART_MSR_ANY_DELTA  0x0F    /* Any of the delta bits! */
  81
  82 #define UART_LSR_TEMT       0x40    /* Transmitter empty */
  83 #define UART_LSR_THRE       0x20    /* Transmit-hold-register empty */
  84 #define UART_LSR_BI         0x10    /* Break interrupt indicator */
  85 #define UART_LSR_FE         0x08    /* Frame error indicator */
  86 #define UART_LSR_PE         0x04    /* Parity error indicator */
  87 #define UART_LSR_OE         0x02    /* Overrun error indicator */
  88 #define UART_LSR_DR         0x01    /* Receiver data ready */
  89 #define UART_LSR_INT_ANY    0x1E    /* Any of the lsr-interrupt-triggering status bits */
  90
  91 /* Interrupt trigger levels. The byte-counts are for 16550A - in newer UARTs the byte-count for each ITL is higher. */
  92
  93 #define UART_FCR_ITL_1      0x00 /* 1 byte ITL */
  94 #define UART_FCR_ITL_2      0x40 /* 4 bytes ITL */
  95 #define UART_FCR_ITL_3      0x80 /* 8 bytes ITL */
  96 #define UART_FCR_ITL_4      0xC0 /* 14 bytes ITL */
  97
  98 #define UART_FCR_DMS        0x08    /* DMA Mode Select */
  99 #define UART_FCR_XFR        0x04    /* XMIT Fifo Reset */
 100 #define UART_FCR_RFR        0x02    /* RCVR Fifo Reset */
 101 #define UART_FCR_FE         0x01    /* FIFO Enable */
 102
 103 #define MAX_XMIT_RETRY      4
 104
 105 static void serial_receive1(void *opaque, const uint8_t *buf, int size);
 106 static void serial_xmit(SerialState *s);
 107
 108 static inline void recv_fifo_put(SerialState *s, uint8_t chr)
 109 {
 110     /* Receive overruns do not overwrite FIFO contents. */
 111     if (!fifo8_is_full(&s->recv_fifo)) {
 112         fifo8_push(&s->recv_fifo, chr);
 113     } else {
 114         s->lsr |= UART_LSR_OE;
 115     }
 116 }
 117
 118 static void serial_update_irq(SerialState *s)
 119 {
 120     uint8_t tmp_iir = UART_IIR_NO_INT;
 121
 122     if ((s->ier & UART_IER_RLSI) && (s->lsr & UART_LSR_INT_ANY)) {
 123         tmp_iir = UART_IIR_RLSI;
 124     } else if ((s->ier & UART_IER_RDI) && s->timeout_ipending) {
 125         /* Note that(s->ier & UART_IER_RDI) can mask this interrupt,
 126          * this is not in the specification but is observed on existing
 127          * hardware.  */
 128         tmp_iir = UART_IIR_CTI;
 129     } else if ((s->ier & UART_IER_RDI) && (s->lsr & UART_LSR_DR) &&
 130                (!(s->fcr & UART_FCR_FE) ||
 131                 s->recv_fifo.num >= s->recv_fifo_itl)) {
 132         tmp_iir = UART_IIR_RDI;
 133     } else if ((s->ier & UART_IER_THRI) && s->thr_ipending) {
 134         tmp_iir = UART_IIR_THRI;
 135     } else if ((s->ier & UART_IER_MSI) && (s->msr & UART_MSR_ANY_DELTA)) {
 136         tmp_iir = UART_IIR_MSI;
 137     }
 138
 139     s->iir = tmp_iir | (s->iir & 0xF0);
 140
 141     if (tmp_iir != UART_IIR_NO_INT) {
 142         qemu_irq_raise(s->irq);
 143     } else {
 144         qemu_irq_lower(s->irq);
 145     }
 146 }
 147
 148 static void serial_update_parameters(SerialState *s)
 149 {
 150     float speed;
 151     int parity, data_bits, stop_bits, frame_size;
 152     QEMUSerialSetParams ssp;
 153
 154     /* Start bit. */
 155     frame_size = 1;
 156     if (s->lcr & 0x08) {
 157         /* Parity bit. */
 158         frame_size++;
 159         if (s->lcr & 0x10)
 160             parity = 'E';
 161         else
 162             parity = 'O';
 163     } else {
 164             parity = 'N';
 165     }
 166     if (s->lcr & 0x04) {
 167         stop_bits = 2;
 168     } else {
 169         stop_bits = 1;
 170     }
 171
 172     data_bits = (s->lcr & 0x03) + 5;
 173     frame_size += data_bits + stop_bits;
 174     /* Zero divisor should give about 3500 baud */
 175     speed = (s->divider == 0) ? 3500 : (float) s->baudbase / s->divider;
 176     ssp.speed = speed;
 177     ssp.parity = parity;
 178     ssp.data_bits = data_bits;
 179     ssp.stop_bits = stop_bits;
 180     s->char_transmit_time =  (NANOSECONDS_PER_SECOND / speed) * frame_size;
 181     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
 182     trace_serial_update_parameters(speed, parity, data_bits, stop_bits);
 183 }
 184
 185 static void serial_update_msl(SerialState *s)
 186 {
 187     uint8_t omsr;
 188     int flags;
 189
 190     timer_del(s->modem_status_poll);
 191
 192     if (qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_GET_TIOCM,
 193                           &flags) == -ENOTSUP) {
 194         s->poll_msl = -1;
 195         return;
 196     }
 197
 198     omsr = s->msr;
 199
 200     s->msr = (flags & CHR_TIOCM_CTS) ? s->msr | UART_MSR_CTS : s->msr & ~UART_MSR_CTS;
 201     s->msr = (flags & CHR_TIOCM_DSR) ? s->msr | UART_MSR_DSR : s->msr & ~UART_MSR_DSR;
 202     s->msr = (flags & CHR_TIOCM_CAR) ? s->msr | UART_MSR_DCD : s->msr & ~UART_MSR_DCD;
 203     s->msr = (flags & CHR_TIOCM_RI) ? s->msr | UART_MSR_RI : s->msr & ~UART_MSR_RI;
 204
 205     if (s->msr != omsr) {
 206          /* Set delta bits */
 207          s->msr = s->msr | ((s->msr >> 4) ^ (omsr >> 4));
 208          /* UART_MSR_TERI only if change was from 1 -> 0 */
 209          if ((s->msr & UART_MSR_TERI) && !(omsr & UART_MSR_RI))
 210              s->msr &= ~UART_MSR_TERI;
 211          serial_update_irq(s);
 212     }
 213
 214     /* The real 16550A apparently has a 250ns response latency to line status changes.
 215        We'll be lazy and poll only every 10ms, and only poll it at all if MSI interrupts are turned on */
 216
 217     if (s->poll_msl) {
 218         timer_mod(s->modem_status_poll, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
 219                   NANOSECONDS_PER_SECOND / 100);
 220     }
 221 }
 222
 223 static gboolean serial_watch_cb(void *do_not_use, GIOCondition cond,
 224                                 void *opaque)
 225 {
 226     SerialState *s = opaque;
 227     s->watch_tag = 0;
 228     serial_xmit(s);
 229     return FALSE;
 230 }
 231
 232 static void serial_xmit(SerialState *s)
 233 {
 234     do {
 235         assert(!(s->lsr & UART_LSR_TEMT));
 236         if (s->tsr_retry == 0) {
 237             assert(!(s->lsr & UART_LSR_THRE));
 238
 239             if (s->fcr & UART_FCR_FE) {
 240                 assert(!fifo8_is_empty(&s->xmit_fifo));
 241                 s->tsr = fifo8_pop(&s->xmit_fifo);
 242                 if (!s->xmit_fifo.num) {
 243                     s->lsr |= UART_LSR_THRE;
 244                 }
 245             } else {
 246                 s->tsr = s->thr;
 247                 s->lsr |= UART_LSR_THRE;
 248             }
 249             if ((s->lsr & UART_LSR_THRE) && !s->thr_ipending) {
 250                 s->thr_ipending = 1;
 251                 serial_update_irq(s);
 252             }
 253         }
 254
 255         if (s->mcr & UART_MCR_LOOP) {
 256             /* in loopback mode, say that we just received a char */
 257             serial_receive1(s, &s->tsr, 1);
 258         } else {
 259             int rc = qemu_chr_fe_write(&s->chr, &s->tsr, 1);
 260
 261             if ((rc == 0 ||
 262                  (rc == -1 && errno == EAGAIN)) &&
 263                 s->tsr_retry < MAX_XMIT_RETRY) {
 264                 assert(s->watch_tag == 0);
 265                 s->watch_tag =
 266                     qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 267                                           serial_watch_cb, s);
 268                 if (s->watch_tag > 0) {
 269                     s->tsr_retry++;
 270                     return;
 271                 }
 272             }
 273         }
 274         s->tsr_retry = 0;
 275
 276         /* Transmit another byte if it is already available. It is only
 277            possible when FIFO is enabled and not empty. */
 278     } while (!(s->lsr & UART_LSR_THRE));
 279
 280     s->last_xmit_ts = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 281     s->lsr |= UART_LSR_TEMT;
 282 }
 283
 284 /* Setter for FCR.
 285    is_load flag means, that value is set while loading VM state
 286    and interrupt should not be invoked */
 287 static void serial_write_fcr(SerialState *s, uint8_t val)
 288 {
 289     /* Set fcr - val only has the bits that are supposed to "stick" */
 290     s->fcr = val;
 291
 292     if (val & UART_FCR_FE) {
 293         s->iir |= UART_IIR_FE;
 294         /* Set recv_fifo trigger Level */
 295         switch (val & 0xC0) {
 296         case UART_FCR_ITL_1:
 297             s->recv_fifo_itl = 1;
 298             break;
 299         case UART_FCR_ITL_2:
 300             s->recv_fifo_itl = 4;
 301             break;
 302         case UART_FCR_ITL_3:
 303             s->recv_fifo_itl = 8;
 304             break;
 305         case UART_FCR_ITL_4:
 306             s->recv_fifo_itl = 14;
 307             break;
 308         }
 309     } else {
 310         s->iir &= ~UART_IIR_FE;
 311     }
 312 }
 313
 314 static void serial_update_tiocm(SerialState *s)
 315 {
 316     int flags;
 317
 318     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_GET_TIOCM, &flags);
 319
 320     flags &= ~(CHR_TIOCM_RTS | CHR_TIOCM_DTR);
 321
 322     if (s->mcr & UART_MCR_RTS) {
 323         flags |= CHR_TIOCM_RTS;
 324     }
 325     if (s->mcr & UART_MCR_DTR) {
 326         flags |= CHR_TIOCM_DTR;
 327     }
 328
 329     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_TIOCM, &flags);
 330 }
 331
 332 static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
 333                                 unsigned size)
 334 {
 335     SerialState *s = opaque;
 336
 337     assert(size == 1 && addr < 8);
 338     trace_serial_write(addr, val);
 339     switch(addr) {
 340     default:
 341     case 0:
 342         if (s->lcr & UART_LCR_DLAB) {
 343             s->divider = deposit32(s->divider, 8 * addr, 8, val);
 344             serial_update_parameters(s);
 345         } else {
 346             s->thr = (uint8_t) val;
 347             if(s->fcr & UART_FCR_FE) {
 348                 /* xmit overruns overwrite data, so make space if needed */
 349                 if (fifo8_is_full(&s->xmit_fifo)) {
 350                     fifo8_pop(&s->xmit_fifo);
 351                 }
 352                 fifo8_push(&s->xmit_fifo, s->thr);
 353             }
 354             s->thr_ipending = 0;
 355             s->lsr &= ~UART_LSR_THRE;
 356             s->lsr &= ~UART_LSR_TEMT;
 357             serial_update_irq(s);
 358             if (s->tsr_retry == 0) {
 359                 serial_xmit(s);
 360             }
 361         }
 362         break;
 363     case 1:
 364         if (s->lcr & UART_LCR_DLAB) {
 365             s->divider = deposit32(s->divider, 8 * addr, 8, val);
 366             serial_update_parameters(s);
 367         } else {
 368             uint8_t changed = (s->ier ^ val) & 0x0f;
 369             s->ier = val & 0x0f;
 370             /* If the backend device is a real serial port, turn polling of the modem
 371              * status lines on physical port on or off depending on UART_IER_MSI state.
 372              */
 373             if ((changed & UART_IER_MSI) && s->poll_msl >= 0) {
 374                 if (s->ier & UART_IER_MSI) {
 375                      s->poll_msl = 1;
 376                      serial_update_msl(s);
 377                 } else {
 378                      timer_del(s->modem_status_poll);
 379                      s->poll_msl = 0;
 380                 }
 381             }
 382
 383             /* Turning on the THRE interrupt on IER can trigger the interrupt
 384              * if LSR.THRE=1, even if it had been masked before by reading IIR.
 385              * This is not in the datasheet, but Windows relies on it.  It is
 386              * unclear if THRE has to be resampled every time THRI becomes
 387              * 1, or only on the rising edge.  Bochs does the latter, and Windows
 388              * always toggles IER to all zeroes and back to all ones, so do the
 389              * same.
 390              *
 391              * If IER.THRI is zero, thr_ipending is not used.  Set it to zero
 392              * so that the thr_ipending subsection is not migrated.
 393              */
 394             if (changed & UART_IER_THRI) {
 395                 if ((s->ier & UART_IER_THRI) && (s->lsr & UART_LSR_THRE)) {
 396                     s->thr_ipending = 1;
 397                 } else {
 398                     s->thr_ipending = 0;
 399                 }
 400             }
 401
 402             if (changed) {
 403                 serial_update_irq(s);
 404             }
 405         }
 406         break;
 407     case 2:
 408         /* Did the enable/disable flag change? If so, make sure FIFOs get flushed */
 409         if ((val ^ s->fcr) & UART_FCR_FE) {
 410             val |= UART_FCR_XFR | UART_FCR_RFR;
 411         }
 412
 413         /* FIFO clear */
 414
 415         if (val & UART_FCR_RFR) {
 416             s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 417             timer_del(s->fifo_timeout_timer);
 418             s->timeout_ipending = 0;
 419             fifo8_reset(&s->recv_fifo);
 420         }
 421
 422         if (val & UART_FCR_XFR) {
 423             s->lsr |= UART_LSR_THRE;
 424             s->thr_ipending = 1;
 425             fifo8_reset(&s->xmit_fifo);
 426         }
 427
 428         serial_write_fcr(s, val & 0xC9);
 429         serial_update_irq(s);
 430         break;
 431     case 3:
 432         {
 433             int break_enable;
 434             s->lcr = val;
 435             serial_update_parameters(s);
 436             break_enable = (val >> 6) & 1;
 437             if (break_enable != s->last_break_enable) {
 438                 s->last_break_enable = break_enable;
 439                 qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 440                                   &break_enable);
 441             }
 442         }
 443         break;
 444     case 4:
 445         {
 446             int old_mcr = s->mcr;
 447             s->mcr = val & 0x1f;
 448             if (val & UART_MCR_LOOP)
 449                 break;
 450
 451             if (s->poll_msl >= 0 && old_mcr != s->mcr) {
 452                 serial_update_tiocm(s);
 453                 /* Update the modem status after a one-character-send wait-time, since there may be a response
 454                    from the device/computer at the other end of the serial line */
 455                 timer_mod(s->modem_status_poll, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time);
 456             }
 457         }
 458         break;
 459     case 5:
 460         break;
 461     case 6:
 462         break;
 463     case 7:
 464         s->scr = val;
 465         break;
 466     }
 467 }
 468
 469 static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size)
 470 {
 471     SerialState *s = opaque;
 472     uint32_t ret;
 473
 474     assert(size == 1 && addr < 8);
 475     switch(addr) {
 476     default:
 477     case 0:
 478         if (s->lcr & UART_LCR_DLAB) {
 479             ret = extract16(s->divider, 8 * addr, 8);
 480         } else {
 481             if(s->fcr & UART_FCR_FE) {
 482                 ret = fifo8_is_empty(&s->recv_fifo) ?
 483                             0 : fifo8_pop(&s->recv_fifo);
 484                 if (s->recv_fifo.num == 0) {
 485                     s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 486                 } else {
 487                     timer_mod(s->fifo_timeout_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time * 4);
 488                 }
 489                 s->timeout_ipending = 0;
 490             } else {
 491                 ret = s->rbr;
 492                 s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
 493             }
 494             serial_update_irq(s);
 495             if (!(s->mcr & UART_MCR_LOOP)) {
 496                 /* in loopback mode, don't receive any data */
 497                 qemu_chr_fe_accept_input(&s->chr);
 498             }
 499         }
 500         break;
 501     case 1:
 502         if (s->lcr & UART_LCR_DLAB) {
 503             ret = extract16(s->divider, 8 * addr, 8);
 504         } else {
 505             ret = s->ier;
 506         }
 507         break;
 508     case 2:
 509         ret = s->iir;
 510         if ((ret & UART_IIR_ID) == UART_IIR_THRI) {
 511             s->thr_ipending = 0;
 512             serial_update_irq(s);
 513         }
 514         break;
 515     case 3:
 516         ret = s->lcr;
 517         break;
 518     case 4:
 519         ret = s->mcr;
 520         break;
 521     case 5:
 522         ret = s->lsr;
 523         /* Clear break and overrun interrupts */
 524         if (s->lsr & (UART_LSR_BI|UART_LSR_OE)) {
 525             s->lsr &= ~(UART_LSR_BI|UART_LSR_OE);
 526             serial_update_irq(s);
 527         }
 528         break;
 529     case 6:
 530         if (s->mcr & UART_MCR_LOOP) {
 531             /* in loopback, the modem output pins are connected to the
 532                inputs */
 533             ret = (s->mcr & 0x0c) << 4;
 534             ret |= (s->mcr & 0x02) << 3;
 535             ret |= (s->mcr & 0x01) << 5;
 536         } else {
 537             if (s->poll_msl >= 0)
 538                 serial_update_msl(s);
 539             ret = s->msr;
 540             /* Clear delta bits & msr int after read, if they were set */
 541             if (s->msr & UART_MSR_ANY_DELTA) {
 542                 s->msr &= 0xF0;
 543                 serial_update_irq(s);
 544             }
 545         }
 546         break;
 547     case 7:
 548         ret = s->scr;
 549         break;
 550     }
 551     trace_serial_read(addr, ret);
 552     return ret;
 553 }
 554
 555 static int serial_can_receive(SerialState *s)
 556 {
 557     if(s->fcr & UART_FCR_FE) {
 558         if (s->recv_fifo.num < UART_FIFO_LENGTH) {
 559             /*
 560              * Advertise (fifo.itl - fifo.count) bytes when count < ITL, and 1
 561              * if above. If UART_FIFO_LENGTH - fifo.count is advertised the
 562              * effect will be to almost always fill the fifo completely before
 563              * the guest has a chance to respond, effectively overriding the ITL
 564              * that the guest has set.
 565              */
 566             return (s->recv_fifo.num <= s->recv_fifo_itl) ?
 567                         s->recv_fifo_itl - s->recv_fifo.num : 1;
 568         } else {
 569             return 0;
 570         }
 571     } else {
 572         return !(s->lsr & UART_LSR_DR);
 573     }
 574 }
 575
 576 static void serial_receive_break(SerialState *s)
 577 {
 578     s->rbr = 0;
 579     /* When the LSR_DR is set a null byte is pushed into the fifo */
 580     recv_fifo_put(s, '\0');
 581     s->lsr |= UART_LSR_BI | UART_LSR_DR;
 582     serial_update_irq(s);
 583 }
 584
 585 /* There's data in recv_fifo and s->rbr has not been read for 4 char transmit times */
 586 static void fifo_timeout_int (void *opaque) {
 587     SerialState *s = opaque;
 588     if (s->recv_fifo.num) {
 589         s->timeout_ipending = 1;
 590         serial_update_irq(s);
 591     }
 592 }
 593
 594 static int serial_can_receive1(void *opaque)
 595 {
 596     SerialState *s = opaque;
 597     return serial_can_receive(s);
 598 }
 599
 600 static void serial_receive1(void *opaque, const uint8_t *buf, int size)
 601 {
 602     SerialState *s = opaque;
 603
 604     if (s->wakeup) {
 605         qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
 606     }
 607     if(s->fcr & UART_FCR_FE) {
 608         int i;
 609         for (i = 0; i < size; i++) {
 610             recv_fifo_put(s, buf[i]);
 611         }
 612         s->lsr |= UART_LSR_DR;
 613         /* call the timeout receive callback in 4 char transmit time */
 614         timer_mod(s->fifo_timeout_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + s->char_transmit_time * 4);
 615     } else {
 616         if (s->lsr & UART_LSR_DR)
 617             s->lsr |= UART_LSR_OE;
 618         s->rbr = buf[0];
 619         s->lsr |= UART_LSR_DR;
 620     }
 621     serial_update_irq(s);
 622 }
 623
 624 static void serial_event(void *opaque, QEMUChrEvent event)
 625 {
 626     SerialState *s = opaque;
 627     if (event == CHR_EVENT_BREAK)
 628         serial_receive_break(s);
 629 }
 630
 631 static int serial_pre_save(void *opaque)
 632 {
 633     SerialState *s = opaque;
 634     s->fcr_vmstate = s->fcr;
 635
 636     return 0;
 637 }
 638
 639 static int serial_pre_load(void *opaque)
 640 {
 641     SerialState *s = opaque;
 642     s->thr_ipending = -1;
 643     s->poll_msl = -1;
 644     return 0;
 645 }
 646
 647 static int serial_post_load(void *opaque, int version_id)
 648 {
 649     SerialState *s = opaque;
 650
 651     if (version_id < 3) {
 652         s->fcr_vmstate = 0;
 653     }
 654     if (s->thr_ipending == -1) {
 655         s->thr_ipending = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
 656     }
 657
 658     if (s->tsr_retry > 0) {
 659         /* tsr_retry > 0 implies LSR.TEMT = 0 (transmitter not empty).  */
 660         if (s->lsr & UART_LSR_TEMT) {
 661             error_report("inconsistent state in serial device "
 662                          "(tsr empty, tsr_retry=%d", s->tsr_retry);
 663             return -1;
 664         }
 665
 666         if (s->tsr_retry > MAX_XMIT_RETRY) {
 667             s->tsr_retry = MAX_XMIT_RETRY;
 668         }
 669
 670         assert(s->watch_tag == 0);
 671         s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 672                                              serial_watch_cb, s);
 673     } else {
 674         /* tsr_retry == 0 implies LSR.TEMT = 1 (transmitter empty).  */
 675         if (!(s->lsr & UART_LSR_TEMT)) {
 676             error_report("inconsistent state in serial device "
 677                          "(tsr not empty, tsr_retry=0");
 678             return -1;
 679         }
 680     }
 681
 682     s->last_break_enable = (s->lcr >> 6) & 1;
 683     /* Initialize fcr via setter to perform essential side-effects */
 684     serial_write_fcr(s, s->fcr_vmstate);
 685     serial_update_parameters(s);
 686     return 0;
 687 }
 688
 689 static bool serial_thr_ipending_needed(void *opaque)
 690 {
 691     SerialState *s = opaque;
 692
 693     if (s->ier & UART_IER_THRI) {
 694         bool expected_value = ((s->iir & UART_IIR_ID) == UART_IIR_THRI);
 695         return s->thr_ipending != expected_value;
 696     } else {
 697         /* LSR.THRE will be sampled again when the interrupt is
 698          * enabled.  thr_ipending is not used in this case, do
 699          * not migrate it.
 700          */
 701         return false;
 702     }
 703 }
 704
 705 static const VMStateDescription vmstate_serial_thr_ipending = {
 706     .name = "serial/thr_ipending",
 707     .version_id = 1,
 708     .minimum_version_id = 1,
 709     .needed = serial_thr_ipending_needed,
 710     .fields = (VMStateField[]) {
 711         VMSTATE_INT32(thr_ipending, SerialState),
 712         VMSTATE_END_OF_LIST()
 713     }
 714 };
 715
 716 static bool serial_tsr_needed(void *opaque)
 717 {
 718     SerialState *s = (SerialState *)opaque;
 719     return s->tsr_retry != 0;
 720 }
 721
 722 static const VMStateDescription vmstate_serial_tsr = {
 723     .name = "serial/tsr",
 724     .version_id = 1,
 725     .minimum_version_id = 1,
 726     .needed = serial_tsr_needed,
 727     .fields = (VMStateField[]) {
 728         VMSTATE_UINT32(tsr_retry, SerialState),
 729         VMSTATE_UINT8(thr, SerialState),
 730         VMSTATE_UINT8(tsr, SerialState),
 731         VMSTATE_END_OF_LIST()
 732     }
 733 };
 734
 735 static bool serial_recv_fifo_needed(void *opaque)
 736 {
 737     SerialState *s = (SerialState *)opaque;
 738     return !fifo8_is_empty(&s->recv_fifo);
 739
 740 }
 741
 742 static const VMStateDescription vmstate_serial_recv_fifo = {
 743     .name = "serial/recv_fifo",
 744     .version_id = 1,
 745     .minimum_version_id = 1,
 746     .needed = serial_recv_fifo_needed,
 747     .fields = (VMStateField[]) {
 748         VMSTATE_STRUCT(recv_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
 749         VMSTATE_END_OF_LIST()
 750     }
 751 };
 752
 753 static bool serial_xmit_fifo_needed(void *opaque)
 754 {
 755     SerialState *s = (SerialState *)opaque;
 756     return !fifo8_is_empty(&s->xmit_fifo);
 757 }
 758
 759 static const VMStateDescription vmstate_serial_xmit_fifo = {
 760     .name = "serial/xmit_fifo",
 761     .version_id = 1,
 762     .minimum_version_id = 1,
 763     .needed = serial_xmit_fifo_needed,
 764     .fields = (VMStateField[]) {
 765         VMSTATE_STRUCT(xmit_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
 766         VMSTATE_END_OF_LIST()
 767     }
 768 };
 769
 770 static bool serial_fifo_timeout_timer_needed(void *opaque)
 771 {
 772     SerialState *s = (SerialState *)opaque;
 773     return timer_pending(s->fifo_timeout_timer);
 774 }
 775
 776 static const VMStateDescription vmstate_serial_fifo_timeout_timer = {
 777     .name = "serial/fifo_timeout_timer",
 778     .version_id = 1,
 779     .minimum_version_id = 1,
 780     .needed = serial_fifo_timeout_timer_needed,
 781     .fields = (VMStateField[]) {
 782         VMSTATE_TIMER_PTR(fifo_timeout_timer, SerialState),
 783         VMSTATE_END_OF_LIST()
 784     }
 785 };
 786
 787 static bool serial_timeout_ipending_needed(void *opaque)
 788 {
 789     SerialState *s = (SerialState *)opaque;
 790     return s->timeout_ipending != 0;
 791 }
 792
 793 static const VMStateDescription vmstate_serial_timeout_ipending = {
 794     .name = "serial/timeout_ipending",
 795     .version_id = 1,
 796     .minimum_version_id = 1,
 797     .needed = serial_timeout_ipending_needed,
 798     .fields = (VMStateField[]) {
 799         VMSTATE_INT32(timeout_ipending, SerialState),
 800         VMSTATE_END_OF_LIST()
 801     }
 802 };
 803
 804 static bool serial_poll_needed(void *opaque)
 805 {
 806     SerialState *s = (SerialState *)opaque;
 807     return s->poll_msl >= 0;
 808 }
 809
 810 static const VMStateDescription vmstate_serial_poll = {
 811     .name = "serial/poll",
 812     .version_id = 1,
 813     .needed = serial_poll_needed,
 814     .minimum_version_id = 1,
 815     .fields = (VMStateField[]) {
 816         VMSTATE_INT32(poll_msl, SerialState),
 817         VMSTATE_TIMER_PTR(modem_status_poll, SerialState),
 818         VMSTATE_END_OF_LIST()
 819     }
 820 };
 821
 822 const VMStateDescription vmstate_serial = {
 823     .name = "serial",
 824     .version_id = 3,
 825     .minimum_version_id = 2,
 826     .pre_save = serial_pre_save,
 827     .pre_load = serial_pre_load,
 828     .post_load = serial_post_load,
 829     .fields = (VMStateField[]) {
 830         VMSTATE_UINT16_V(divider, SerialState, 2),
 831         VMSTATE_UINT8(rbr, SerialState),
 832         VMSTATE_UINT8(ier, SerialState),
 833         VMSTATE_UINT8(iir, SerialState),
 834         VMSTATE_UINT8(lcr, SerialState),
 835         VMSTATE_UINT8(mcr, SerialState),
 836         VMSTATE_UINT8(lsr, SerialState),
 837         VMSTATE_UINT8(msr, SerialState),
 838         VMSTATE_UINT8(scr, SerialState),
 839         VMSTATE_UINT8_V(fcr_vmstate, SerialState, 3),
 840         VMSTATE_END_OF_LIST()
 841     },
 842     .subsections = (const VMStateDescription*[]) {
 843         &vmstate_serial_thr_ipending,
 844         &vmstate_serial_tsr,
 845         &vmstate_serial_recv_fifo,
 846         &vmstate_serial_xmit_fifo,
 847         &vmstate_serial_fifo_timeout_timer,
 848         &vmstate_serial_timeout_ipending,
 849         &vmstate_serial_poll,
 850         NULL
 851     }
 852 };
 853
 854 static void serial_reset(void *opaque)
 855 {
 856     SerialState *s = opaque;
 857
 858     if (s->watch_tag > 0) {
 859         g_source_remove(s->watch_tag);
 860         s->watch_tag = 0;
 861     }
 862
 863     s->rbr = 0;
 864     s->ier = 0;
 865     s->iir = UART_IIR_NO_INT;
 866     s->lcr = 0;
 867     s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
 868     s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
 869     /* Default to 9600 baud, 1 start bit, 8 data bits, 1 stop bit, no parity. */
 870     s->divider = 0x0C;
 871     s->mcr = UART_MCR_OUT2;
 872     s->scr = 0;
 873     s->tsr_retry = 0;
 874     s->char_transmit_time = (NANOSECONDS_PER_SECOND / 9600) * 10;
 875     s->poll_msl = 0;
 876
 877     s->timeout_ipending = 0;
 878     timer_del(s->fifo_timeout_timer);
 879     timer_del(s->modem_status_poll);
 880
 881     fifo8_reset(&s->recv_fifo);
 882     fifo8_reset(&s->xmit_fifo);
 883
 884     s->last_xmit_ts = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 885
 886     s->thr_ipending = 0;
 887     s->last_break_enable = 0;
 888     qemu_irq_lower(s->irq);
 889
 890     serial_update_msl(s);
 891     s->msr &= ~UART_MSR_ANY_DELTA;
 892 }
 893
 894 static int serial_be_change(void *opaque)
 895 {
 896     SerialState *s = opaque;
 897
 898     qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1,
 899                              serial_event, serial_be_change, s, NULL, true);
 900
 901     serial_update_parameters(s);
 902
 903     qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
 904                       &s->last_break_enable);
 905
 906     s->poll_msl = (s->ier & UART_IER_MSI) ? 1 : 0;
 907     serial_update_msl(s);
 908
 909     if (s->poll_msl >= 0 && !(s->mcr & UART_MCR_LOOP)) {
 910         serial_update_tiocm(s);
 911     }
 912
 913     if (s->watch_tag > 0) {
 914         g_source_remove(s->watch_tag);
 915         s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
 916                                              serial_watch_cb, s);
 917     }
 918
 919     return 0;
 920 }
 921
 922 static void serial_realize(DeviceState *dev, Error **errp)
 923 {
 924     SerialState *s = SERIAL(dev);
 925
 926     s->modem_status_poll = timer_new_ns(QEMU_CLOCK_VIRTUAL, (QEMUTimerCB *) serial_update_msl, s);
 927
 928     s->fifo_timeout_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, (QEMUTimerCB *) fifo_timeout_int, s);
 929     qemu_register_reset(serial_reset, s);
 930
 931     qemu_chr_fe_set_handlers(&s->chr, serial_can_receive1, serial_receive1,
 932                              serial_event, serial_be_change, s, NULL, true);
 933     fifo8_create(&s->recv_fifo, UART_FIFO_LENGTH);
 934     fifo8_create(&s->xmit_fifo, UART_FIFO_LENGTH);
 935     serial_reset(s);
 936 }
 937
 938 static void serial_unrealize(DeviceState *dev)
 939 {
 940     SerialState *s = SERIAL(dev);
 941
 942     qemu_chr_fe_deinit(&s->chr, false);
 943
 944     timer_free(s->modem_status_poll);
 945
 946     timer_free(s->fifo_timeout_timer);
 947
 948     fifo8_destroy(&s->recv_fifo);
 949     fifo8_destroy(&s->xmit_fifo);
 950
 951     qemu_unregister_reset(serial_reset, s);
 952 }
 953
 954 /* Change the main reference oscillator frequency. */
 955 void serial_set_frequency(SerialState *s, uint32_t frequency)
 956 {
 957     s->baudbase = frequency;
 958     serial_update_parameters(s);
 959 }
 960
 961 const MemoryRegionOps serial_io_ops = {
 962     .read = serial_ioport_read,
 963     .write = serial_ioport_write,
 964     .valid = {
 965         .unaligned = 1,
 966     },
 967     .impl = {
 968         .min_access_size = 1,
 969         .max_access_size = 1,
 970     },
 971     .endianness = DEVICE_LITTLE_ENDIAN,
 972 };
 973
 974 static Property serial_properties[] = {
 975     DEFINE_PROP_CHR("chardev", SerialState, chr),
 976     DEFINE_PROP_UINT32("baudbase", SerialState, baudbase, 115200),
 977     DEFINE_PROP_BOOL("wakeup", SerialState, wakeup, false),
 978     DEFINE_PROP_END_OF_LIST(),
 979 };
 980
 981 static void serial_class_init(ObjectClass *klass, void* data)
 982 {
 983     DeviceClass *dc = DEVICE_CLASS(klass);
 984
 985     /* internal device for serialio/serialmm, not user-creatable */
 986     dc->user_creatable = false;
 987     dc->realize = serial_realize;
 988     dc->unrealize = serial_unrealize;
 989     device_class_set_props(dc, serial_properties);
 990 }
 991
 992 static const TypeInfo serial_info = {
 993     .name = TYPE_SERIAL,
 994     .parent = TYPE_DEVICE,
 995     .instance_size = sizeof(SerialState),
 996     .class_init = serial_class_init,
 997 };
 998
 999 /* Memory mapped interface */
1000 static uint64_t serial_mm_read(void *opaque, hwaddr addr,
1001                                unsigned size)
1002 {
1003     SerialMM *s = SERIAL_MM(opaque);
1004     return serial_ioport_read(&s->serial, addr >> s->regshift, 1);
1005 }
1006
1007 static void serial_mm_write(void *opaque, hwaddr addr,
1008                             uint64_t value, unsigned size)
1009 {
1010     SerialMM *s = SERIAL_MM(opaque);
1011     value &= 255;
1012     serial_ioport_write(&s->serial, addr >> s->regshift, 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 static void serial_mm_realize(DeviceState *dev, Error **errp)
1040 {
1041     SerialMM *smm = SERIAL_MM(dev);
1042     SerialState *s = &smm->serial;
1043
1044     if (!qdev_realize(DEVICE(s), NULL, errp)) {
1045         return;
1046     }
1047
1048     memory_region_init_io(&s->io, OBJECT(dev),
1049                           &serial_mm_ops[smm->endianness], smm, "serial",
1050                           8 << smm->regshift);
1051     sysbus_init_mmio(SYS_BUS_DEVICE(smm), &s->io);
1052     sysbus_init_irq(SYS_BUS_DEVICE(smm), &smm->serial.irq);
1053 }
1054
1055 static const VMStateDescription vmstate_serial_mm = {
1056     .name = "serial",
1057     .version_id = 3,
1058     .minimum_version_id = 2,
1059     .fields = (VMStateField[]) {
1060         VMSTATE_STRUCT(serial, SerialMM, 0, vmstate_serial, SerialState),
1061         VMSTATE_END_OF_LIST()
1062     }
1063 };
1064
1065 SerialMM *serial_mm_init(MemoryRegion *address_space,
1066                          hwaddr base, int regshift,
1067                          qemu_irq irq, int baudbase,
1068                          Chardev *chr, enum device_endian end)
1069 {
1070     SerialMM *smm = SERIAL_MM(qdev_new(TYPE_SERIAL_MM));
1071     MemoryRegion *mr;
1072
1073     qdev_prop_set_uint8(DEVICE(smm), "regshift", regshift);
1074     qdev_prop_set_uint32(DEVICE(smm), "baudbase", baudbase);
1075     qdev_prop_set_chr(DEVICE(smm), "chardev", chr);
1076     qdev_set_legacy_instance_id(DEVICE(smm), base, 2);
1077     qdev_prop_set_uint8(DEVICE(smm), "endianness", end);
1078     sysbus_realize_and_unref(SYS_BUS_DEVICE(smm), &error_fatal);
1079
1080     sysbus_connect_irq(SYS_BUS_DEVICE(smm), 0, irq);
1081     mr = sysbus_mmio_get_region(SYS_BUS_DEVICE(smm), 0);
1082     memory_region_add_subregion(address_space, base, mr);
1083
1084     return smm;
1085 }
1086
1087 static void serial_mm_instance_init(Object *o)
1088 {
1089     SerialMM *smm = SERIAL_MM(o);
1090
1091     object_initialize_child(o, "serial", &smm->serial, TYPE_SERIAL);
1092
1093     qdev_alias_all_properties(DEVICE(&smm->serial), o);
1094 }
1095
1096 static Property serial_mm_properties[] = {
1097     /*
1098      * Set the spacing between adjacent memory-mapped UART registers.
1099      * Each register will be at (1 << regshift) bytes after the
1100      * previous one.
1101      */
1102     DEFINE_PROP_UINT8("regshift", SerialMM, regshift, 0),
1103     DEFINE_PROP_UINT8("endianness", SerialMM, endianness, DEVICE_NATIVE_ENDIAN),
1104     DEFINE_PROP_END_OF_LIST(),
1105 };
1106
1107 static void serial_mm_class_init(ObjectClass *oc, void *data)
1108 {
1109     DeviceClass *dc = DEVICE_CLASS(oc);
1110
1111     device_class_set_props(dc, serial_mm_properties);
1112     dc->realize = serial_mm_realize;
1113     dc->vmsd = &vmstate_serial_mm;
1114 }
1115
1116 static const TypeInfo serial_mm_info = {
1117     .name = TYPE_SERIAL_MM,
1118     .parent = TYPE_SYS_BUS_DEVICE,
1119     .class_init = serial_mm_class_init,
1120     .instance_init = serial_mm_instance_init,
1121     .instance_size = sizeof(SerialMM),
1122 };
1123
1124 static void serial_register_types(void)
1125 {
1126     type_register_static(&serial_info);
1127     type_register_static(&serial_mm_info);
1128 }
1129
1130 type_init(serial_register_types)