gdb/ser-go32.c

   1 /* Remote serial interface for local (hardwired) serial ports for GO32.
   2    Copyright 1992, 1993, 2000, 2001 Free Software Foundation, Inc.
   3
   4    Contributed by Nigel Stephens, Algorithmics Ltd. (nigel@algor.co.uk).
   5
   6    This version uses DPMI interrupts to handle buffered i/o
   7    without the separate "asynctsr" program.
   8
   9    This file is part of GDB.
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 2 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program; if not, write to the Free Software
  23    Foundation, Inc., 59 Temple Place - Suite 330,
  24    Boston, MA 02111-1307, USA.  */
  25
  26 #include "defs.h"
  27 #include "gdbcmd.h"
  28 #include "serial.h"
  29 #include "gdb_string.h"
  30
  31
  32 /*
  33  * NS16550 UART registers
  34  */
  35
  36 #define COM1ADDR        0x3f8
  37 #define COM2ADDR        0x2f8
  38 #define COM3ADDR        0x3e8
  39 #define COM4ADDR        0x3e0
  40
  41 #define com_data        0       /* data register (R/W) */
  42 #define com_dlbl        0       /* divisor latch low (W) */
  43 #define com_ier         1       /* interrupt enable (W) */
  44 #define com_dlbh        1       /* divisor latch high (W) */
  45 #define com_iir         2       /* interrupt identification (R) */
  46 #define com_fifo        2       /* FIFO control (W) */
  47 #define com_lctl        3       /* line control register (R/W) */
  48 #define com_cfcr        3       /* line control register (R/W) */
  49 #define com_mcr         4       /* modem control register (R/W) */
  50 #define com_lsr         5       /* line status register (R/W) */
  51 #define com_msr         6       /* modem status register (R/W) */
  52
  53 /*
  54  * Constants for computing 16 bit baud rate divisor (lower byte
  55  * in com_dlbl, upper in com_dlbh) from 1.8432MHz crystal.  Divisor is
  56  * 1.8432 MHz / (16 * X) for X bps.  If the baud rate can't be set
  57  * to within +- (desired_rate*SPEED_TOLERANCE/1000) bps, we fail.
  58  */
  59 #define COMTICK         (1843200/16)
  60 #define SPEED_TOLERANCE 30      /* thousandths; real == desired +- 3.0% */
  61
  62 /* interrupt enable register */
  63 #define IER_ERXRDY      0x1     /* int on rx ready */
  64 #define IER_ETXRDY      0x2     /* int on tx ready */
  65 #define IER_ERLS        0x4     /* int on line status change */
  66 #define IER_EMSC        0x8     /* int on modem status change */
  67
  68 /* interrupt identification register */
  69 #define IIR_FIFO_MASK   0xc0    /* set if FIFOs are enabled */
  70 #define IIR_IMASK       0xf     /* interrupt cause mask */
  71 #define IIR_NOPEND      0x1     /* nothing pending */
  72 #define IIR_RLS         0x6     /* receive line status */
  73 #define IIR_RXRDY       0x4     /* receive ready */
  74 #define IIR_RXTOUT      0xc     /* receive timeout */
  75 #define IIR_TXRDY       0x2     /* transmit ready */
  76 #define IIR_MLSC        0x0     /* modem status */
  77
  78
  79 /* fifo control register */
  80 #define FIFO_ENABLE     0x01    /* enable fifo */
  81 #define FIFO_RCV_RST    0x02    /* reset receive fifo */
  82 #define FIFO_XMT_RST    0x04    /* reset transmit fifo */
  83 #define FIFO_DMA_MODE   0x08    /* enable dma mode */
  84 #define FIFO_TRIGGER_1  0x00    /* trigger at 1 char */
  85 #define FIFO_TRIGGER_4  0x40    /* trigger at 4 chars */
  86 #define FIFO_TRIGGER_8  0x80    /* trigger at 8 chars */
  87 #define FIFO_TRIGGER_14 0xc0    /* trigger at 14 chars */
  88
  89 /* character format control register */
  90 #define CFCR_DLAB       0x80    /* divisor latch */
  91 #define CFCR_SBREAK     0x40    /* send break */
  92 #define CFCR_PZERO      0x30    /* zero parity */
  93 #define CFCR_PONE       0x20    /* one parity */
  94 #define CFCR_PEVEN      0x10    /* even parity */
  95 #define CFCR_PODD       0x00    /* odd parity */
  96 #define CFCR_PENAB      0x08    /* parity enable */
  97 #define CFCR_STOPB      0x04    /* 2 stop bits */
  98 #define CFCR_8BITS      0x03    /* 8 data bits */
  99 #define CFCR_7BITS      0x02    /* 7 data bits */
 100 #define CFCR_6BITS      0x01    /* 6 data bits */
 101 #define CFCR_5BITS      0x00    /* 5 data bits */
 102
 103 /* modem control register */
 104 #define MCR_LOOPBACK    0x10    /* loopback */
 105 #define MCR_IENABLE     0x08    /* output 2 = int enable */
 106 #define MCR_DRS         0x04    /* output 1 = xxx */
 107 #define MCR_RTS         0x02    /* enable RTS */
 108 #define MCR_DTR         0x01    /* enable DTR */
 109
 110 /* line status register */
 111 #define LSR_RCV_FIFO    0x80    /* error in receive fifo */
 112 #define LSR_TSRE        0x40    /* transmitter empty */
 113 #define LSR_TXRDY       0x20    /* transmitter ready */
 114 #define LSR_BI          0x10    /* break detected */
 115 #define LSR_FE          0x08    /* framing error */
 116 #define LSR_PE          0x04    /* parity error */
 117 #define LSR_OE          0x02    /* overrun error */
 118 #define LSR_RXRDY       0x01    /* receiver ready */
 119 #define LSR_RCV_MASK    0x1f
 120
 121 /* modem status register */
 122 #define MSR_DCD         0x80
 123 #define MSR_RI          0x40
 124 #define MSR_DSR         0x20
 125 #define MSR_CTS         0x10
 126 #define MSR_DDCD        0x08
 127 #define MSR_TERI        0x04
 128 #define MSR_DDSR        0x02
 129 #define MSR_DCTS        0x01
 130
 131 #include <time.h>
 132 #include <dos.h>
 133 #include <go32.h>
 134 #include <dpmi.h>
 135 typedef unsigned long u_long;
 136
 137 /* 16550 rx fifo trigger point */
 138 #define FIFO_TRIGGER    FIFO_TRIGGER_4
 139
 140 /* input buffer size */
 141 #define CBSIZE  4096
 142
 143 #define RAWHZ   18
 144
 145 #ifdef DOS_STATS
 146 #define CNT_RX          16
 147 #define CNT_TX          17
 148 #define CNT_STRAY       18
 149 #define CNT_ORUN        19
 150 #define NCNT            20
 151
 152 static int intrcnt;
 153 static int cnts[NCNT];
 154 static char *cntnames[NCNT] =
 155 {
 156   /* h/w interrupt counts. */
 157   "mlsc", "nopend", "txrdy", "?3",
 158   "rxrdy", "?5", "rls", "?7",
 159   "?8", "?9", "?a", "?b",
 160   "rxtout", "?d", "?e", "?f",
 161   /* s/w counts. */
 162   "rxcnt", "txcnt", "stray", "swoflo"
 163 };
 164
 165 #define COUNT(x) cnts[x]++
 166 #else
 167 #define COUNT(x)
 168 #endif
 169
 170 /* Main interrupt controller port addresses. */
 171 #define ICU_BASE        0x20
 172 #define ICU_OCW2        (ICU_BASE + 0)
 173 #define ICU_MASK        (ICU_BASE + 1)
 174
 175 /* Original interrupt controller mask register. */
 176 unsigned char icu_oldmask;
 177
 178 /* Maximum of 8 interrupts (we don't handle the slave icu yet). */
 179 #define NINTR   8
 180
 181 static struct intrupt
 182   {
 183     char inuse;
 184     struct dos_ttystate *port;
 185     _go32_dpmi_seginfo old_rmhandler;
 186     _go32_dpmi_seginfo old_pmhandler;
 187     _go32_dpmi_seginfo new_rmhandler;
 188     _go32_dpmi_seginfo new_pmhandler;
 189     _go32_dpmi_registers regs;
 190   }
 191 intrupts[NINTR];
 192
 193
 194 static struct dos_ttystate
 195   {
 196     int base;
 197     int irq;
 198     int refcnt;
 199     struct intrupt *intrupt;
 200     int fifo;
 201     int baudrate;
 202     unsigned char cbuf[CBSIZE];
 203     unsigned int first;
 204     unsigned int count;
 205     int txbusy;
 206     unsigned char old_mcr;
 207     int ferr;
 208     int perr;
 209     int oflo;
 210     int msr;
 211   }
 212 ports[4] =
 213 {
 214   {
 215     COM1ADDR, 4, 0, NULL, 0, 0, "", 0, 0, 0, 0, 0, 0, 0, 0
 216   }
 217   ,
 218   {
 219     COM2ADDR, 3, 0, NULL, 0, 0, "", 0, 0, 0, 0, 0, 0, 0, 0
 220   }
 221   ,
 222   {
 223     COM3ADDR, 4, 0, NULL, 0, 0, "", 0, 0, 0, 0, 0, 0, 0, 0
 224   }
 225   ,
 226   {
 227     COM4ADDR, 3, 0, NULL, 0, 0, "", 0, 0, 0, 0, 0, 0, 0, 0
 228   }
 229 };
 230
 231 static int dos_open (serial_t scb, const char *name);
 232 static void dos_raw (serial_t scb);
 233 static int dos_readchar (serial_t scb, int timeout);
 234 static int dos_setbaudrate (serial_t scb, int rate);
 235 static int dos_write (serial_t scb, const char *str, int len);
 236 static void dos_close (serial_t scb);
 237 static serial_ttystate dos_get_tty_state (serial_t scb);
 238 static int dos_set_tty_state (serial_t scb, serial_ttystate state);
 239 static int dos_baudconv (int rate);
 240
 241 #define inb(p,a)        inportb((p)->base + (a))
 242 #define outb(p,a,v)     outportb((p)->base + (a), (v))
 243 #define disable()       asm volatile ("cli");
 244 #define enable()        asm volatile ("sti");
 245
 246
 247 static int
 248 dos_getc (volatile struct dos_ttystate *port)
 249 {
 250   int c;
 251
 252   if (port->count == 0)
 253     return -1;
 254
 255   c = port->cbuf[port->first];
 256   disable ();
 257   port->first = (port->first + 1) & (CBSIZE - 1);
 258   port->count--;
 259   enable ();
 260   return c;
 261 }
 262
 263
 264 static int
 265 dos_putc (int c, struct dos_ttystate *port)
 266 {
 267   if (port->count >= CBSIZE - 1)
 268     return -1;
 269   port->cbuf[(port->first + port->count) & (CBSIZE - 1)] = c;
 270   port->count++;
 271   return 0;
 272 }
 273 \f
 274
 275
 276 static void
 277 dos_comisr (int irq)
 278 {
 279   struct dos_ttystate *port;
 280   unsigned char iir, lsr, c;
 281
 282   disable ();                   /* Paranoia */
 283   outportb (ICU_OCW2, 0x20);    /* End-Of-Interrupt */
 284 #ifdef DOS_STATS
 285   ++intrcnt;
 286 #endif
 287
 288   port = intrupts[irq].port;
 289   if (!port)
 290     {
 291       COUNT (CNT_STRAY);
 292       return;                   /* not open */
 293     }
 294
 295   while (1)
 296     {
 297       iir = inb (port, com_iir) & IIR_IMASK;
 298       switch (iir)
 299         {
 300
 301         case IIR_RLS:
 302           lsr = inb (port, com_lsr);
 303           goto rx;
 304
 305         case IIR_RXTOUT:
 306         case IIR_RXRDY:
 307           lsr = 0;
 308
 309         rx:
 310           do
 311             {
 312               c = inb (port, com_data);
 313               if (lsr & (LSR_BI | LSR_FE | LSR_PE | LSR_OE))
 314                 {
 315                   if (lsr & (LSR_BI | LSR_FE))
 316                     port->ferr++;
 317                   else if (lsr & LSR_PE)
 318                     port->perr++;
 319                   if (lsr & LSR_OE)
 320                     port->oflo++;
 321                 }
 322
 323               if (dos_putc (c, port) < 0)
 324                 {
 325                   COUNT (CNT_ORUN);
 326                 }
 327               else
 328                 {
 329                   COUNT (CNT_RX);
 330                 }
 331             }
 332           while ((lsr = inb (port, com_lsr)) & LSR_RXRDY);
 333           break;
 334
 335         case IIR_MLSC:
 336           /* could be used to flowcontrol Tx */
 337           port->msr = inb (port, com_msr);
 338           break;
 339
 340         case IIR_TXRDY:
 341           port->txbusy = 0;
 342           break;
 343
 344         case IIR_NOPEND:
 345           /* no more pending interrupts, all done */
 346           return;
 347
 348         default:
 349           /* unexpected interrupt, ignore */
 350           break;
 351         }
 352       COUNT (iir);
 353     }
 354 }
 355
 356 #define ISRNAME(x) dos_comisr##x
 357 #define ISR(x) static void ISRNAME(x)(void) {dos_comisr(x);}
 358
 359 ISR (0) ISR (1) ISR (2) ISR (3)
 360 ISR (4) ISR (5) ISR (6) ISR (7)
 361
 362 typedef void (*isr_t) (void);
 363
 364 static isr_t isrs[NINTR] =
 365   {
 366        ISRNAME (0), ISRNAME (1), ISRNAME (2), ISRNAME (3),
 367        ISRNAME (4), ISRNAME (5), ISRNAME (6), ISRNAME (7)
 368   };
 369 \f
 370
 371
 372 static struct intrupt *
 373 dos_hookirq (unsigned int irq)
 374 {
 375   struct intrupt *intr;
 376   unsigned int vec;
 377   isr_t isr;
 378
 379   if (irq >= NINTR)
 380     return 0;
 381
 382   intr = &intrupts[irq];
 383   if (intr->inuse)
 384     return 0;
 385
 386   vec = 0x08 + irq;
 387   isr = isrs[irq];
 388
 389   /* setup real mode handler */
 390   _go32_dpmi_get_real_mode_interrupt_vector (vec, &intr->old_rmhandler);
 391
 392   intr->new_rmhandler.pm_selector = _go32_my_cs ();
 393   intr->new_rmhandler.pm_offset = (u_long) isr;
 394   if (_go32_dpmi_allocate_real_mode_callback_iret (&intr->new_rmhandler,
 395                                                    &intr->regs))
 396     {
 397       return 0;
 398     }
 399
 400   if (_go32_dpmi_set_real_mode_interrupt_vector (vec, &intr->new_rmhandler))
 401     {
 402       return 0;
 403     }
 404
 405   /* setup protected mode handler */
 406   _go32_dpmi_get_protected_mode_interrupt_vector (vec, &intr->old_pmhandler);
 407
 408   intr->new_pmhandler.pm_selector = _go32_my_cs ();
 409   intr->new_pmhandler.pm_offset = (u_long) isr;
 410   _go32_dpmi_allocate_iret_wrapper (&intr->new_pmhandler);
 411
 412   if (_go32_dpmi_set_protected_mode_interrupt_vector (vec,
 413                                                       &intr->new_pmhandler))
 414     {
 415       return 0;
 416     }
 417
 418   /* setup interrupt controller mask */
 419   disable ();
 420   outportb (ICU_MASK, inportb (ICU_MASK) & ~(1 << irq));
 421   enable ();
 422
 423   intr->inuse = 1;
 424   return intr;
 425 }
 426
 427
 428 static void
 429 dos_unhookirq (struct intrupt *intr)
 430 {
 431   unsigned int irq, vec;
 432   unsigned char mask;
 433
 434   irq = intr - intrupts;
 435   vec = 0x08 + irq;
 436
 437   /* restore old interrupt mask bit */
 438   mask = 1 << irq;
 439   disable ();
 440   outportb (ICU_MASK, inportb (ICU_MASK) | (mask & icu_oldmask));
 441   enable ();
 442
 443   /* remove real mode handler */
 444   _go32_dpmi_set_real_mode_interrupt_vector (vec, &intr->old_rmhandler);
 445   _go32_dpmi_free_real_mode_callback (&intr->new_rmhandler);
 446
 447   /* remove protected mode handler */
 448   _go32_dpmi_set_protected_mode_interrupt_vector (vec, &intr->old_pmhandler);
 449   _go32_dpmi_free_iret_wrapper (&intr->new_pmhandler);
 450   intr->inuse = 0;
 451 }
 452 \f
 453
 454
 455 static int
 456 dos_open (serial_t scb, const char *name)
 457 {
 458   struct dos_ttystate *port;
 459   int fd, i;
 460
 461   if (strncasecmp (name, "/dev/", 5) == 0)
 462     name += 5;
 463   else if (strncasecmp (name, "\\dev\\", 5) == 0)
 464     name += 5;
 465
 466   if (strlen (name) != 4 || strncasecmp (name, "com", 3) != 0)
 467     {
 468       errno = ENOENT;
 469       return -1;
 470     }
 471
 472   if (name[3] < '1' || name[3] > '4')
 473     {
 474       errno = ENOENT;
 475       return -1;
 476     }
 477
 478   /* FIXME: this is a Bad Idea (tm)!  One should *never* invent file
 479      handles, since they might be already used by other files/devices.
 480      The Right Way to do this is to create a real handle by dup()'ing
 481      some existing one.  */
 482   fd = name[3] - '1';
 483   port = &ports[fd];
 484   if (port->refcnt++ > 0)
 485     {
 486       /* Device already opened another user.  Just point at it. */
 487       scb->fd = fd;
 488       return 0;
 489     }
 490
 491   /* force access to ID reg */
 492   outb (port, com_cfcr, 0);
 493   outb (port, com_iir, 0);
 494   for (i = 0; i < 17; i++)
 495     {
 496       if ((inb (port, com_iir) & 0x38) == 0)
 497         goto ok;
 498       (void) inb (port, com_data);      /* clear recv */
 499     }
 500   errno = ENODEV;
 501   return -1;
 502
 503 ok:
 504   /* disable all interrupts in chip */
 505   outb (port, com_ier, 0);
 506
 507   /* tentatively enable 16550 fifo, and see if it responds */
 508   outb (port, com_fifo,
 509         FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER);
 510   sleep (1);
 511   port->fifo = ((inb (port, com_iir) & IIR_FIFO_MASK) == IIR_FIFO_MASK);
 512
 513   /* clear pending status reports. */
 514   (void) inb (port, com_lsr);
 515   (void) inb (port, com_msr);
 516
 517   /* enable external interrupt gate (to avoid floating IRQ) */
 518   outb (port, com_mcr, MCR_IENABLE);
 519
 520   /* hook up interrupt handler and initialise icu */
 521   port->intrupt = dos_hookirq (port->irq);
 522   if (!port->intrupt)
 523     {
 524       outb (port, com_mcr, 0);
 525       outb (port, com_fifo, 0);
 526       errno = ENODEV;
 527       return -1;
 528     }
 529
 530   disable ();
 531
 532   /* record port */
 533   port->intrupt->port = port;
 534   scb->fd = fd;
 535
 536   /* clear rx buffer, tx busy flag and overflow count */
 537   port->first = port->count = 0;
 538   port->txbusy = 0;
 539   port->oflo = 0;
 540
 541   /* set default baud rate and mode: 9600,8,n,1 */
 542   i = dos_baudconv (port->baudrate = 9600);
 543   outb (port, com_cfcr, CFCR_DLAB);
 544   outb (port, com_dlbl, i & 0xff);
 545   outb (port, com_dlbh, i >> 8);
 546   outb (port, com_cfcr, CFCR_8BITS);
 547
 548   /* enable all interrupts */
 549   outb (port, com_ier, IER_ETXRDY | IER_ERXRDY | IER_ERLS | IER_EMSC);
 550
 551   /* enable DTR & RTS */
 552   outb (port, com_mcr, MCR_DTR | MCR_RTS | MCR_IENABLE);
 553
 554   enable ();
 555
 556   return 0;
 557 }
 558
 559
 560 static void
 561 dos_close (serial_t scb)
 562 {
 563   struct dos_ttystate *port;
 564   struct intrupt *intrupt;
 565
 566   if (!scb)
 567     return;
 568
 569   port = &ports[scb->fd];
 570
 571   if (port->refcnt-- > 1)
 572     return;
 573
 574   if (!(intrupt = port->intrupt))
 575     return;
 576
 577   /* disable interrupts, fifo, flow control */
 578   disable ();
 579   port->intrupt = 0;
 580   intrupt->port = 0;
 581   outb (port, com_fifo, 0);
 582   outb (port, com_ier, 0);
 583   enable ();
 584
 585   /* unhook handler, and disable interrupt gate */
 586   dos_unhookirq (intrupt);
 587   outb (port, com_mcr, 0);
 588
 589   /* Check for overflow errors */
 590   if (port->oflo)
 591     {
 592       fprintf_unfiltered (gdb_stderr,
 593                           "Serial input overruns occurred.\n");
 594       fprintf_unfiltered (gdb_stderr, "This system %s handle %d baud.\n",
 595                           port->fifo ? "cannot" : "needs a 16550 to",
 596                           port->baudrate);
 597     }
 598 }
 599 \f
 600
 601
 602 static int
 603 dos_noop (serial_t scb)
 604 {
 605   return 0;
 606 }
 607
 608 static void
 609 dos_raw (serial_t scb)
 610 {
 611   /* Always in raw mode */
 612 }
 613
 614 static int
 615 dos_readchar (serial_t scb, int timeout)
 616 {
 617   struct dos_ttystate *port = &ports[scb->fd];
 618   long then;
 619   int c;
 620
 621   then = rawclock () + (timeout * RAWHZ);
 622   while ((c = dos_getc (port)) < 0)
 623     {
 624       if (timeout >= 0 && (rawclock () - then) >= 0)
 625         return SERIAL_TIMEOUT;
 626     }
 627
 628   return c;
 629 }
 630
 631
 632 static serial_ttystate
 633 dos_get_tty_state (serial_t scb)
 634 {
 635   struct dos_ttystate *port = &ports[scb->fd];
 636   struct dos_ttystate *state;
 637
 638   /* Are they asking about a port we opened?  */
 639   if (port->refcnt <= 0)
 640     {
 641       /* We've never heard about this port.  We should fail this call,
 642          unless they are asking about one of the 3 standard handles,
 643          in which case we pretend the handle was open by us if it is
 644          connected to a terminal device.  This is beacuse Unix
 645          terminals use the serial interface, so GDB expects the
 646          standard handles to go through here.  */
 647       if (scb->fd >= 3 || !isatty (scb->fd))
 648         return NULL;
 649     }
 650
 651   state = (struct dos_ttystate *) xmalloc (sizeof *state);
 652   *state = *port;
 653   return (serial_ttystate) state;
 654 }
 655
 656 static int
 657 dos_set_tty_state (serial_t scb, serial_ttystate ttystate)
 658 {
 659   struct dos_ttystate *state;
 660
 661   state = (struct dos_ttystate *) ttystate;
 662   dos_setbaudrate (scb, state->baudrate);
 663   return 0;
 664 }
 665
 666 static int
 667 dos_noflush_set_tty_state (serial_t scb, serial_ttystate new_ttystate,
 668                            serial_ttystate old_ttystate)
 669 {
 670   struct dos_ttystate *state;
 671
 672   state = (struct dos_ttystate *) new_ttystate;
 673   dos_setbaudrate (scb, state->baudrate);
 674   return 0;
 675 }
 676
 677 static int
 678 dos_flush_input (serial_t scb)
 679 {
 680   struct dos_ttystate *port = &ports[scb->fd];
 681   disable ();
 682   port->first = port->count = 0;
 683   if (port->fifo)
 684     outb (port, com_fifo, FIFO_ENABLE | FIFO_RCV_RST | FIFO_TRIGGER);
 685   enable ();
 686   return 0;
 687 }
 688
 689 static void
 690 dos_print_tty_state (serial_t scb, serial_ttystate ttystate,
 691                      struct ui_file *stream)
 692 {
 693   /* Nothing to print */
 694   return;
 695 }
 696
 697 static int
 698 dos_baudconv (int rate)
 699 {
 700   long x, err;
 701
 702   if (rate <= 0)
 703     return -1;
 704
 705 #define divrnd(n, q)    (((n) * 2 / (q) + 1) / 2) /* divide and round off */
 706   x = divrnd (COMTICK, rate);
 707   if (x <= 0)
 708     return -1;
 709
 710   err = divrnd (1000 * COMTICK, x * rate) - 1000;
 711   if (err < 0)
 712     err = -err;
 713   if (err > SPEED_TOLERANCE)
 714     return -1;
 715 #undef divrnd
 716   return x;
 717 }
 718
 719
 720 static int
 721 dos_setbaudrate (serial_t scb, int rate)
 722 {
 723   struct dos_ttystate *port = &ports[scb->fd];
 724
 725   if (port->baudrate != rate)
 726     {
 727       int x;
 728       unsigned char cfcr;
 729
 730       x = dos_baudconv (rate);
 731       if (x <= 0)
 732         {
 733           fprintf_unfiltered (gdb_stderr, "%d: impossible baudrate\n", rate);
 734           errno = EINVAL;
 735           return -1;
 736         }
 737
 738       disable ();
 739       cfcr = inb (port, com_cfcr);
 740
 741       outb (port, com_cfcr, CFCR_DLAB);
 742       outb (port, com_dlbl, x & 0xff);
 743       outb (port, com_dlbh, x >> 8);
 744       outb (port, com_cfcr, cfcr);
 745       port->baudrate = rate;
 746       enable ();
 747     }
 748
 749   return 0;
 750 }
 751
 752 static int
 753 dos_setstopbits (serial_t scb, int num)
 754 {
 755   struct dos_ttystate *port = &ports[scb->fd];
 756   unsigned char cfcr;
 757
 758   disable ();
 759   cfcr = inb (port, com_cfcr);
 760
 761   switch (num)
 762     {
 763     case SERIAL_1_STOPBITS:
 764       outb (port, com_cfcr, cfcr & ~CFCR_STOPB);
 765       break;
 766     case SERIAL_1_AND_A_HALF_STOPBITS:
 767     case SERIAL_2_STOPBITS:
 768       outb (port, com_cfcr, cfcr | CFCR_STOPB);
 769       break;
 770     default:
 771       enable ();
 772       return 1;
 773     }
 774   enable ();
 775
 776   return 0;
 777 }
 778
 779 static int
 780 dos_write (serial_t scb, const char *str, int len)
 781 {
 782   volatile struct dos_ttystate *port = &ports[scb->fd];
 783   int fifosize = port->fifo ? 16 : 1;
 784   long then;
 785   int cnt;
 786
 787   while (len > 0)
 788     {
 789       /* send the data, fifosize bytes at a time */
 790       cnt = fifosize > len ? len : fifosize;
 791       port->txbusy = 1;
 792       /* Francisco Pastor <fpastor.etra-id@etra.es> says OUTSB messes
 793          up the communications with UARTs with FIFOs.  */
 794 #ifdef UART_FIFO_WORKS
 795       outportsb (port->base + com_data, str, cnt);
 796       str += cnt;
 797       len -= cnt;
 798 #else
 799       for ( ; cnt > 0; cnt--, len--)
 800         outportb (port->base + com_data, *str++);
 801 #endif
 802 #ifdef DOS_STATS
 803       cnts[CNT_TX] += cnt;
 804 #endif
 805       /* wait for transmission to complete (max 1 sec) */
 806       then = rawclock () + RAWHZ;
 807       while (port->txbusy)
 808         {
 809           if ((rawclock () - then) >= 0)
 810             {
 811               errno = EIO;
 812               return SERIAL_ERROR;
 813             }
 814         }
 815     }
 816   return 0;
 817 }
 818
 819
 820 static int
 821 dos_sendbreak (serial_t scb)
 822 {
 823   volatile struct dos_ttystate *port = &ports[scb->fd];
 824   unsigned char cfcr;
 825   long then;
 826
 827   cfcr = inb (port, com_cfcr);
 828   outb (port, com_cfcr, cfcr | CFCR_SBREAK);
 829
 830   /* 0.25 sec delay */
 831   then = rawclock () + RAWHZ / 4;
 832   while ((rawclock () - then) < 0)
 833     continue;
 834
 835   outb (port, com_cfcr, cfcr);
 836   return 0;
 837 }
 838
 839
 840 static struct serial_ops dos_ops =
 841 {
 842   "hardwire",
 843   0,
 844   dos_open,
 845   dos_close,
 846   dos_readchar,
 847   dos_write,
 848   dos_noop,                     /* flush output */
 849   dos_flush_input,
 850   dos_sendbreak,
 851   dos_raw,
 852   dos_get_tty_state,
 853   dos_set_tty_state,
 854   dos_print_tty_state,
 855   dos_noflush_set_tty_state,
 856   dos_setbaudrate,
 857   dos_setstopbits,
 858   dos_noop,                     /* wait for output to drain */
 859   (void (*)(serial_t, int))NULL /* change into async mode */
 860 };
 861
 862
 863 static void
 864 dos_info (char *arg, int from_tty)
 865 {
 866   struct dos_ttystate *port;
 867 #ifdef DOS_STATS
 868   int i;
 869 #endif
 870
 871   for (port = ports; port < &ports[4]; port++)
 872     {
 873       if (port->baudrate == 0)
 874         continue;
 875       printf_filtered ("Port:\tCOM%ld (%sactive)\n", (long)(port - ports) + 1,
 876                        port->intrupt ? "" : "not ");
 877       printf_filtered ("Addr:\t0x%03x (irq %d)\n", port->base, port->irq);
 878       printf_filtered ("16550:\t%s\n", port->fifo ? "yes" : "no");
 879       printf_filtered ("Speed:\t%d baud\n", port->baudrate);
 880       printf_filtered ("Errs:\tframing %d parity %d overflow %d\n\n",
 881                        port->ferr, port->perr, port->oflo);
 882     }
 883
 884 #ifdef DOS_STATS
 885   printf_filtered ("\nTotal interrupts: %d\n", intrcnt);
 886   for (i = 0; i < NCNT; i++)
 887     if (cnts[i])
 888       printf_filtered ("%s:\t%d\n", cntnames[i], cnts[i]);
 889 #endif
 890 }
 891
 892
 893 void
 894 _initialize_ser_dos (void)
 895 {
 896   serial_add_interface (&dos_ops);
 897
 898   /* Save original interrupt mask register. */
 899   icu_oldmask = inportb (ICU_MASK);
 900
 901   /* Mark fixed motherboard irqs as inuse. */
 902   intrupts[0].inuse =           /* timer tick */
 903     intrupts[1].inuse =         /* keyboard */
 904     intrupts[2].inuse = 1;      /* slave icu */
 905
 906   add_show_from_set (
 907                       add_set_cmd ("com1base", class_obscure, var_zinteger,
 908                                    (char *) &ports[0].base,
 909                                    "Set COM1 base i/o port address.",
 910                                    &setlist),
 911                       &showlist);
 912
 913   add_show_from_set (
 914                       add_set_cmd ("com1irq", class_obscure, var_zinteger,
 915                                    (char *) &ports[0].irq,
 916                                    "Set COM1 interrupt request.",
 917                                    &setlist),
 918                       &showlist);
 919
 920   add_show_from_set (
 921                       add_set_cmd ("com2base", class_obscure, var_zinteger,
 922                                    (char *) &ports[1].base,
 923                                    "Set COM2 base i/o port address.",
 924                                    &setlist),
 925                       &showlist);
 926
 927   add_show_from_set (
 928                       add_set_cmd ("com2irq", class_obscure, var_zinteger,
 929                                    (char *) &ports[1].irq,
 930                                    "Set COM2 interrupt request.",
 931                                    &setlist),
 932                       &showlist);
 933
 934   add_show_from_set (
 935                       add_set_cmd ("com3base", class_obscure, var_zinteger,
 936                                    (char *) &ports[2].base,
 937                                    "Set COM3 base i/o port address.",
 938                                    &setlist),
 939                       &showlist);
 940
 941   add_show_from_set (
 942                       add_set_cmd ("com3irq", class_obscure, var_zinteger,
 943                                    (char *) &ports[2].irq,
 944                                    "Set COM3 interrupt request.",
 945                                    &setlist),
 946                       &showlist);
 947
 948   add_show_from_set (
 949                       add_set_cmd ("com4base", class_obscure, var_zinteger,
 950                                    (char *) &ports[3].base,
 951                                    "Set COM4 base i/o port address.",
 952                                    &setlist),
 953                       &showlist);
 954
 955   add_show_from_set (
 956                       add_set_cmd ("com4irq", class_obscure, var_zinteger,
 957                                    (char *) &ports[3].irq,
 958                                    "Set COM4 interrupt request.",
 959                                    &setlist),
 960                       &showlist);
 961
 962   add_info ("serial", dos_info,
 963             "Print DOS serial port status.");
 964 }