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 == 2) { 349 s->divider = (s->divider & 0xff00) | val; 350 } else if (size == 4) { 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); 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 } 1061