drivers/staging/generic_serial/rio/riotty.c

   1 /*
   2 ** -----------------------------------------------------------------------------
   3 **
   4 **  Perle Specialix driver for Linux
   5 **  Ported from existing RIO Driver for SCO sources.
   6  *
   7  *  (C) 1990 - 2000 Specialix International Ltd., Byfleet, Surrey, UK.
   8  *
   9  *      This program is free software; you can redistribute it and/or modify
  10  *      it under the terms of the GNU General Public License as published by
  11  *      the Free Software Foundation; either version 2 of the License, or
  12  *      (at your option) any later version.
  13  *
  14  *      This program is distributed in the hope that it will be useful,
  15  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *      GNU General Public License for more details.
  18  *
  19  *      You should have received a copy of the GNU General Public License
  20  *      along with this program; if not, write to the Free Software
  21  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 **
  23 **      Module          : riotty.c
  24 **      SID             : 1.3
  25 **      Last Modified   : 11/6/98 10:33:47
  26 **      Retrieved       : 11/6/98 10:33:50
  27 **
  28 **  ident @(#)riotty.c  1.3
  29 **
  30 ** -----------------------------------------------------------------------------
  31 */
  32
  33 #define __EXPLICIT_DEF_H__
  34
  35 #include <linux/module.h>
  36 #include <linux/sched.h>
  37 #include <linux/errno.h>
  38 #include <linux/tty.h>
  39 #include <linux/string.h>
  40 #include <asm/io.h>
  41 #include <asm/system.h>
  42 #include <asm/string.h>
  43 #include <asm/uaccess.h>
  44
  45 #include <linux/termios.h>
  46
  47 #include <linux/serial.h>
  48
  49 #include <linux/generic_serial.h>
  50
  51
  52 #include "linux_compat.h"
  53 #include "rio_linux.h"
  54 #include "pkt.h"
  55 #include "daemon.h"
  56 #include "rio.h"
  57 #include "riospace.h"
  58 #include "cmdpkt.h"
  59 #include "map.h"
  60 #include "rup.h"
  61 #include "port.h"
  62 #include "riodrvr.h"
  63 #include "rioinfo.h"
  64 #include "func.h"
  65 #include "errors.h"
  66 #include "pci.h"
  67
  68 #include "parmmap.h"
  69 #include "unixrup.h"
  70 #include "board.h"
  71 #include "host.h"
  72 #include "phb.h"
  73 #include "link.h"
  74 #include "cmdblk.h"
  75 #include "route.h"
  76 #include "cirrus.h"
  77 #include "rioioctl.h"
  78 #include "param.h"
  79
  80 static void RIOClearUp(struct Port *PortP);
  81
  82 /* Below belongs in func.h */
  83 int RIOShortCommand(struct rio_info *p, struct Port *PortP, int command, int len, int arg);
  84
  85
  86 extern struct rio_info *p;
  87
  88
  89 int riotopen(struct tty_struct *tty, struct file *filp)
  90 {
  91         unsigned int SysPort;
  92         int repeat_this = 250;
  93         struct Port *PortP;     /* pointer to the port structure */
  94         unsigned long flags;
  95         int retval = 0;
  96
  97         func_enter();
  98
  99         /* Make sure driver_data is NULL in case the rio isn't booted jet. Else gs_close
 100            is going to oops.
 101          */
 102         tty->driver_data = NULL;
 103
 104         SysPort = rio_minor(tty);
 105
 106         if (p->RIOFailed) {
 107                 rio_dprintk(RIO_DEBUG_TTY, "System initialisation failed\n");
 108                 func_exit();
 109                 return -ENXIO;
 110         }
 111
 112         rio_dprintk(RIO_DEBUG_TTY, "port open SysPort %d (mapped:%d)\n", SysPort, p->RIOPortp[SysPort]->Mapped);
 113
 114         /*
 115          ** Validate that we have received a legitimate request.
 116          ** Currently, just check that we are opening a port on
 117          ** a host card that actually exists, and that the port
 118          ** has been mapped onto a host.
 119          */
 120         if (SysPort >= RIO_PORTS) {     /* out of range ? */
 121                 rio_dprintk(RIO_DEBUG_TTY, "Illegal port number %d\n", SysPort);
 122                 func_exit();
 123                 return -ENXIO;
 124         }
 125
 126         /*
 127          ** Grab pointer to the port structure
 128          */
 129         PortP = p->RIOPortp[SysPort];   /* Get control struc */
 130         rio_dprintk(RIO_DEBUG_TTY, "PortP: %p\n", PortP);
 131         if (!PortP->Mapped) {   /* we aren't mapped yet! */
 132                 /*
 133                  ** The system doesn't know which RTA this port
 134                  ** corresponds to.
 135                  */
 136                 rio_dprintk(RIO_DEBUG_TTY, "port not mapped into system\n");
 137                 func_exit();
 138                 return -ENXIO;
 139         }
 140
 141         tty->driver_data = PortP;
 142
 143         PortP->gs.port.tty = tty;
 144         PortP->gs.port.count++;
 145
 146         rio_dprintk(RIO_DEBUG_TTY, "%d bytes in tx buffer\n", PortP->gs.xmit_cnt);
 147
 148         retval = gs_init_port(&PortP->gs);
 149         if (retval) {
 150                 PortP->gs.port.count--;
 151                 return -ENXIO;
 152         }
 153         /*
 154          ** If the host hasn't been booted yet, then
 155          ** fail
 156          */
 157         if ((PortP->HostP->Flags & RUN_STATE) != RC_RUNNING) {
 158                 rio_dprintk(RIO_DEBUG_TTY, "Host not running\n");
 159                 func_exit();
 160                 return -ENXIO;
 161         }
 162
 163         /*
 164          ** If the RTA has not booted yet and the user has chosen to block
 165          ** until the RTA is present then we must spin here waiting for
 166          ** the RTA to boot.
 167          */
 168         /* I find the above code a bit hairy. I find the below code
 169            easier to read and shorter. Now, if it works too that would
 170            be great... -- REW
 171          */
 172         rio_dprintk(RIO_DEBUG_TTY, "Checking if RTA has booted... \n");
 173         while (!(PortP->HostP->Mapping[PortP->RupNum].Flags & RTA_BOOTED)) {
 174                 if (!PortP->WaitUntilBooted) {
 175                         rio_dprintk(RIO_DEBUG_TTY, "RTA never booted\n");
 176                         func_exit();
 177                         return -ENXIO;
 178                 }
 179
 180                 /* Under Linux you'd normally use a wait instead of this
 181                    busy-waiting. I'll stick with the old implementation for
 182                    now. --REW
 183                  */
 184                 if (RIODelay(PortP, HUNDRED_MS) == RIO_FAIL) {
 185                         rio_dprintk(RIO_DEBUG_TTY, "RTA_wait_for_boot: EINTR in delay \n");
 186                         func_exit();
 187                         return -EINTR;
 188                 }
 189                 if (repeat_this-- <= 0) {
 190                         rio_dprintk(RIO_DEBUG_TTY, "Waiting for RTA to boot timeout\n");
 191                         func_exit();
 192                         return -EIO;
 193                 }
 194         }
 195         rio_dprintk(RIO_DEBUG_TTY, "RTA has been booted\n");
 196         rio_spin_lock_irqsave(&PortP->portSem, flags);
 197         if (p->RIOHalted) {
 198                 goto bombout;
 199         }
 200
 201         /*
 202          ** If the port is in the final throws of being closed,
 203          ** we should wait here (politely), waiting
 204          ** for it to finish, so that it doesn't close us!
 205          */
 206         while ((PortP->State & RIO_CLOSING) && !p->RIOHalted) {
 207                 rio_dprintk(RIO_DEBUG_TTY, "Waiting for RIO_CLOSING to go away\n");
 208                 if (repeat_this-- <= 0) {
 209                         rio_dprintk(RIO_DEBUG_TTY, "Waiting for not idle closed broken by signal\n");
 210                         RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 211                         retval = -EINTR;
 212                         goto bombout;
 213                 }
 214                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 215                 if (RIODelay(PortP, HUNDRED_MS) == RIO_FAIL) {
 216                         rio_spin_lock_irqsave(&PortP->portSem, flags);
 217                         retval = -EINTR;
 218                         goto bombout;
 219                 }
 220                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 221         }
 222
 223         if (!PortP->Mapped) {
 224                 rio_dprintk(RIO_DEBUG_TTY, "Port unmapped while closing!\n");
 225                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 226                 retval = -ENXIO;
 227                 func_exit();
 228                 return retval;
 229         }
 230
 231         if (p->RIOHalted) {
 232                 goto bombout;
 233         }
 234
 235 /*
 236 ** 15.10.1998 ARG - ESIL 0761 part fix
 237 ** RIO has it's own CTSFLOW and RTSFLOW flags in 'Config' in the port structure,
 238 ** we need to make sure that the flags are clear when the port is opened.
 239 */
 240         /* Uh? Suppose I turn these on and then another process opens
 241            the port again? The flags get cleared! Not good. -- REW */
 242         if (!(PortP->State & (RIO_LOPEN | RIO_MOPEN))) {
 243                 PortP->Config &= ~(RIO_CTSFLOW | RIO_RTSFLOW);
 244         }
 245
 246         if (!(PortP->firstOpen)) {      /* First time ? */
 247                 rio_dprintk(RIO_DEBUG_TTY, "First open for this port\n");
 248
 249
 250                 PortP->firstOpen++;
 251                 PortP->CookMode = 0;    /* XXX RIOCookMode(tp); */
 252                 PortP->InUse = NOT_INUSE;
 253
 254                 /* Tentative fix for bug PR27. Didn't work. */
 255                 /* PortP->gs.xmit_cnt = 0; */
 256
 257                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 258
 259                 /* Someone explain to me why this delay/config is
 260                    here. If I read the docs correctly the "open"
 261                    command piggybacks the parameters immediately.
 262                    -- REW */
 263                 RIOParam(PortP, RIOC_OPEN, 1, OK_TO_SLEEP); /* Open the port */
 264                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 265
 266                 /*
 267                  ** wait for the port to be not closed.
 268                  */
 269                 while (!(PortP->PortState & PORT_ISOPEN) && !p->RIOHalted) {
 270                         rio_dprintk(RIO_DEBUG_TTY, "Waiting for PORT_ISOPEN-currently %x\n", PortP->PortState);
 271                         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 272                         if (RIODelay(PortP, HUNDRED_MS) == RIO_FAIL) {
 273                                 rio_dprintk(RIO_DEBUG_TTY, "Waiting for open to finish broken by signal\n");
 274                                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 275                                 func_exit();
 276                                 return -EINTR;
 277                         }
 278                         rio_spin_lock_irqsave(&PortP->portSem, flags);
 279                 }
 280
 281                 if (p->RIOHalted) {
 282                         retval = -EIO;
 283                       bombout:
 284                         /*                    RIOClearUp( PortP ); */
 285                         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 286                         return retval;
 287                 }
 288                 rio_dprintk(RIO_DEBUG_TTY, "PORT_ISOPEN found\n");
 289         }
 290         rio_dprintk(RIO_DEBUG_TTY, "Modem - test for carrier\n");
 291         /*
 292          ** ACTION
 293          ** insert test for carrier here. -- ???
 294          ** I already see that test here. What's the deal? -- REW
 295          */
 296         if ((PortP->gs.port.tty->termios->c_cflag & CLOCAL) ||
 297                         (PortP->ModemState & RIOC_MSVR1_CD)) {
 298                 rio_dprintk(RIO_DEBUG_TTY, "open(%d) Modem carr on\n", SysPort);
 299                 /*
 300                    tp->tm.c_state |= CARR_ON;
 301                    wakeup((caddr_t) &tp->tm.c_canq);
 302                  */
 303                 PortP->State |= RIO_CARR_ON;
 304                 wake_up_interruptible(&PortP->gs.port.open_wait);
 305         } else {        /* no carrier - wait for DCD */
 306                         /*
 307                    while (!(PortP->gs.port.tty->termios->c_state & CARR_ON) &&
 308                    !(filp->f_flags & O_NONBLOCK) && !p->RIOHalted )
 309                  */
 310                 while (!(PortP->State & RIO_CARR_ON) && !(filp->f_flags & O_NONBLOCK) && !p->RIOHalted) {
 311                                 rio_dprintk(RIO_DEBUG_TTY, "open(%d) sleeping for carr on\n", SysPort);
 312                         /*
 313                            PortP->gs.port.tty->termios->c_state |= WOPEN;
 314                          */
 315                         PortP->State |= RIO_WOPEN;
 316                         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 317                         if (RIODelay(PortP, HUNDRED_MS) == RIO_FAIL) {
 318                                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 319                                 /*
 320                                  ** ACTION: verify that this is a good thing
 321                                  ** to do here. -- ???
 322                                  ** I think it's OK. -- REW
 323                                  */
 324                                 rio_dprintk(RIO_DEBUG_TTY, "open(%d) sleeping for carr broken by signal\n", SysPort);
 325                                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 326                                 /*
 327                                    tp->tm.c_state &= ~WOPEN;
 328                                  */
 329                                 PortP->State &= ~RIO_WOPEN;
 330                                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 331                                 func_exit();
 332                                 return -EINTR;
 333                         }
 334                         rio_spin_lock_irqsave(&PortP->portSem, flags);
 335                 }
 336                 PortP->State &= ~RIO_WOPEN;
 337         }
 338         if (p->RIOHalted)
 339                 goto bombout;
 340         rio_dprintk(RIO_DEBUG_TTY, "Setting RIO_MOPEN\n");
 341         PortP->State |= RIO_MOPEN;
 342
 343         if (p->RIOHalted)
 344                 goto bombout;
 345
 346         rio_dprintk(RIO_DEBUG_TTY, "high level open done\n");
 347
 348         /*
 349          ** Count opens for port statistics reporting
 350          */
 351         if (PortP->statsGather)
 352                 PortP->opens++;
 353
 354         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 355         rio_dprintk(RIO_DEBUG_TTY, "Returning from open\n");
 356         func_exit();
 357         return 0;
 358 }
 359
 360 /*
 361 ** RIOClose the port.
 362 ** The operating system thinks that this is last close for the device.
 363 ** As there are two interfaces to the port (Modem and tty), we need to
 364 ** check that both are closed before we close the device.
 365 */
 366 int riotclose(void *ptr)
 367 {
 368         struct Port *PortP = ptr;       /* pointer to the port structure */
 369         int deleted = 0;
 370         int try = -1;           /* Disable the timeouts by setting them to -1 */
 371         int repeat_this = -1;   /* Congrats to those having 15 years of
 372                                    uptime! (You get to break the driver.) */
 373         unsigned long end_time;
 374         struct tty_struct *tty;
 375         unsigned long flags;
 376         int rv = 0;
 377
 378         rio_dprintk(RIO_DEBUG_TTY, "port close SysPort %d\n", PortP->PortNum);
 379
 380         /* PortP = p->RIOPortp[SysPort]; */
 381         rio_dprintk(RIO_DEBUG_TTY, "Port is at address %p\n", PortP);
 382         /* tp = PortP->TtyP; *//* Get tty */
 383         tty = PortP->gs.port.tty;
 384         rio_dprintk(RIO_DEBUG_TTY, "TTY is at address %p\n", tty);
 385
 386         if (PortP->gs.closing_wait)
 387                 end_time = jiffies + PortP->gs.closing_wait;
 388         else
 389                 end_time = jiffies + MAX_SCHEDULE_TIMEOUT;
 390
 391         rio_spin_lock_irqsave(&PortP->portSem, flags);
 392
 393         /*
 394          ** Setting this flag will make any process trying to open
 395          ** this port block until we are complete closing it.
 396          */
 397         PortP->State |= RIO_CLOSING;
 398
 399         if ((PortP->State & RIO_DELETED)) {
 400                 rio_dprintk(RIO_DEBUG_TTY, "Close on deleted RTA\n");
 401                 deleted = 1;
 402         }
 403
 404         if (p->RIOHalted) {
 405                 RIOClearUp(PortP);
 406                 rv = -EIO;
 407                 goto close_end;
 408         }
 409
 410         rio_dprintk(RIO_DEBUG_TTY, "Clear bits\n");
 411         /*
 412          ** clear the open bits for this device
 413          */
 414         PortP->State &= ~RIO_MOPEN;
 415         PortP->State &= ~RIO_CARR_ON;
 416         PortP->ModemState &= ~RIOC_MSVR1_CD;
 417         /*
 418          ** If the device was open as both a Modem and a tty line
 419          ** then we need to wimp out here, as the port has not really
 420          ** been finally closed (gee, whizz!) The test here uses the
 421          ** bit for the OTHER mode of operation, to see if THAT is
 422          ** still active!
 423          */
 424         if ((PortP->State & (RIO_LOPEN | RIO_MOPEN))) {
 425                 /*
 426                  ** The port is still open for the other task -
 427                  ** return, pretending that we are still active.
 428                  */
 429                 rio_dprintk(RIO_DEBUG_TTY, "Channel %d still open !\n", PortP->PortNum);
 430                 PortP->State &= ~RIO_CLOSING;
 431                 if (PortP->firstOpen)
 432                         PortP->firstOpen--;
 433                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 434                 return -EIO;
 435         }
 436
 437         rio_dprintk(RIO_DEBUG_TTY, "Closing down - everything must go!\n");
 438
 439         PortP->State &= ~RIO_DYNOROD;
 440
 441         /*
 442          ** This is where we wait for the port
 443          ** to drain down before closing. Bye-bye....
 444          ** (We never meant to do this)
 445          */
 446         rio_dprintk(RIO_DEBUG_TTY, "Timeout 1 starts\n");
 447
 448         if (!deleted)
 449                 while ((PortP->InUse != NOT_INUSE) && !p->RIOHalted && (PortP->TxBufferIn != PortP->TxBufferOut)) {
 450                         if (repeat_this-- <= 0) {
 451                                 rv = -EINTR;
 452                                 rio_dprintk(RIO_DEBUG_TTY, "Waiting for not idle closed broken by signal\n");
 453                                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 454                                 goto close_end;
 455                         }
 456                         rio_dprintk(RIO_DEBUG_TTY, "Calling timeout to flush in closing\n");
 457                         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 458                         if (RIODelay_ni(PortP, HUNDRED_MS * 10) == RIO_FAIL) {
 459                                 rio_dprintk(RIO_DEBUG_TTY, "RTA EINTR in delay \n");
 460                                 rv = -EINTR;
 461                                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 462                                 goto close_end;
 463                         }
 464                         rio_spin_lock_irqsave(&PortP->portSem, flags);
 465                 }
 466
 467         PortP->TxBufferIn = PortP->TxBufferOut = 0;
 468         repeat_this = 0xff;
 469
 470         PortP->InUse = 0;
 471         if ((PortP->State & (RIO_LOPEN | RIO_MOPEN))) {
 472                 /*
 473                  ** The port has been re-opened for the other task -
 474                  ** return, pretending that we are still active.
 475                  */
 476                 rio_dprintk(RIO_DEBUG_TTY, "Channel %d re-open!\n", PortP->PortNum);
 477                 PortP->State &= ~RIO_CLOSING;
 478                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 479                 if (PortP->firstOpen)
 480                         PortP->firstOpen--;
 481                 return -EIO;
 482         }
 483
 484         if (p->RIOHalted) {
 485                 RIOClearUp(PortP);
 486                 goto close_end;
 487         }
 488
 489         /* Can't call RIOShortCommand with the port locked. */
 490         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 491
 492         if (RIOShortCommand(p, PortP, RIOC_CLOSE, 1, 0) == RIO_FAIL) {
 493                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 494                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 495                 goto close_end;
 496         }
 497
 498         if (!deleted)
 499                 while (try && (PortP->PortState & PORT_ISOPEN)) {
 500                         try--;
 501                         if (time_after(jiffies, end_time)) {
 502                                 rio_dprintk(RIO_DEBUG_TTY, "Run out of tries - force the bugger shut!\n");
 503                                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 504                                 break;
 505                         }
 506                         rio_dprintk(RIO_DEBUG_TTY, "Close: PortState:ISOPEN is %d\n", PortP->PortState & PORT_ISOPEN);
 507
 508                         if (p->RIOHalted) {
 509                                 RIOClearUp(PortP);
 510                                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 511                                 goto close_end;
 512                         }
 513                         if (RIODelay(PortP, HUNDRED_MS) == RIO_FAIL) {
 514                                 rio_dprintk(RIO_DEBUG_TTY, "RTA EINTR in delay \n");
 515                                 RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE);
 516                                 break;
 517                         }
 518                 }
 519         rio_spin_lock_irqsave(&PortP->portSem, flags);
 520         rio_dprintk(RIO_DEBUG_TTY, "Close: try was %d on completion\n", try);
 521
 522         /* RIOPreemptiveCmd(p, PortP, RIOC_FCLOSE); */
 523
 524 /*
 525 ** 15.10.1998 ARG - ESIL 0761 part fix
 526 ** RIO has it's own CTSFLOW and RTSFLOW flags in 'Config' in the port structure,** we need to make sure that the flags are clear when the port is opened.
 527 */
 528         PortP->Config &= ~(RIO_CTSFLOW | RIO_RTSFLOW);
 529
 530         /*
 531          ** Count opens for port statistics reporting
 532          */
 533         if (PortP->statsGather)
 534                 PortP->closes++;
 535
 536 close_end:
 537         /* XXX: Why would a "DELETED" flag be reset here? I'd have
 538            thought that a "deleted" flag means that the port was
 539            permanently gone, but here we can make it reappear by it
 540            being in close during the "deletion".
 541          */
 542         PortP->State &= ~(RIO_CLOSING | RIO_DELETED);
 543         if (PortP->firstOpen)
 544                 PortP->firstOpen--;
 545         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 546         rio_dprintk(RIO_DEBUG_TTY, "Return from close\n");
 547         return rv;
 548 }
 549
 550
 551
 552 static void RIOClearUp(struct Port *PortP)
 553 {
 554         rio_dprintk(RIO_DEBUG_TTY, "RIOHalted set\n");
 555         PortP->Config = 0;      /* Direct semaphore */
 556         PortP->PortState = 0;
 557         PortP->firstOpen = 0;
 558         PortP->FlushCmdBodge = 0;
 559         PortP->ModemState = PortP->CookMode = 0;
 560         PortP->Mapped = 0;
 561         PortP->WflushFlag = 0;
 562         PortP->MagicFlags = 0;
 563         PortP->RxDataStart = 0;
 564         PortP->TxBufferIn = 0;
 565         PortP->TxBufferOut = 0;
 566 }
 567
 568 /*
 569 ** Put a command onto a port.
 570 ** The PortPointer, command, length and arg are passed.
 571 ** The len is the length *inclusive* of the command byte,
 572 ** and so for a command that takes no data, len==1.
 573 ** The arg is a single byte, and is only used if len==2.
 574 ** Other values of len aren't allowed, and will cause
 575 ** a panic.
 576 */
 577 int RIOShortCommand(struct rio_info *p, struct Port *PortP, int command, int len, int arg)
 578 {
 579         struct PKT __iomem *PacketP;
 580         int retries = 20;       /* at 10 per second -> 2 seconds */
 581         unsigned long flags;
 582
 583         rio_dprintk(RIO_DEBUG_TTY, "entering shortcommand.\n");
 584
 585         if (PortP->State & RIO_DELETED) {
 586                 rio_dprintk(RIO_DEBUG_TTY, "Short command to deleted RTA ignored\n");
 587                 return RIO_FAIL;
 588         }
 589         rio_spin_lock_irqsave(&PortP->portSem, flags);
 590
 591         /*
 592          ** If the port is in use for pre-emptive command, then wait for it to
 593          ** be free again.
 594          */
 595         while ((PortP->InUse != NOT_INUSE) && !p->RIOHalted) {
 596                 rio_dprintk(RIO_DEBUG_TTY, "Waiting for not in use (%d)\n", retries);
 597                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 598                 if (retries-- <= 0) {
 599                         return RIO_FAIL;
 600                 }
 601                 if (RIODelay_ni(PortP, HUNDRED_MS) == RIO_FAIL) {
 602                         return RIO_FAIL;
 603                 }
 604                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 605         }
 606         if (PortP->State & RIO_DELETED) {
 607                 rio_dprintk(RIO_DEBUG_TTY, "Short command to deleted RTA ignored\n");
 608                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 609                 return RIO_FAIL;
 610         }
 611
 612         while (!can_add_transmit(&PacketP, PortP) && !p->RIOHalted) {
 613                 rio_dprintk(RIO_DEBUG_TTY, "Waiting to add short command to queue (%d)\n", retries);
 614                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 615                 if (retries-- <= 0) {
 616                         rio_dprintk(RIO_DEBUG_TTY, "out of tries. Failing\n");
 617                         return RIO_FAIL;
 618                 }
 619                 if (RIODelay_ni(PortP, HUNDRED_MS) == RIO_FAIL) {
 620                         return RIO_FAIL;
 621                 }
 622                 rio_spin_lock_irqsave(&PortP->portSem, flags);
 623         }
 624
 625         if (p->RIOHalted) {
 626                 rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 627                 return RIO_FAIL;
 628         }
 629
 630         /*
 631          ** set the command byte and the argument byte
 632          */
 633         writeb(command, &PacketP->data[0]);
 634
 635         if (len == 2)
 636                 writeb(arg, &PacketP->data[1]);
 637
 638         /*
 639          ** set the length of the packet and set the command bit.
 640          */
 641         writeb(PKT_CMD_BIT | len, &PacketP->len);
 642
 643         add_transmit(PortP);
 644         /*
 645          ** Count characters transmitted for port statistics reporting
 646          */
 647         if (PortP->statsGather)
 648                 PortP->txchars += len;
 649
 650         rio_spin_unlock_irqrestore(&PortP->portSem, flags);
 651         return p->RIOHalted ? RIO_FAIL : ~RIO_FAIL;
 652 }
 653
 654