drivers/parport/ieee1284.c

   1 /* $Id: parport_ieee1284.c,v 1.4 1997/10/19 21:37:21 philip Exp $
   2  * IEEE-1284 implementation for parport.
   3  *
   4  * Authors: Phil Blundell <philb@gnu.org>
   5  *          Carsten Gross <carsten@sol.wohnheim.uni-ulm.de>
   6  *          Jose Renau <renau@acm.org>
   7  *          Tim Waugh <tim@cyberelk.demon.co.uk> (largely rewritten)
   8  *
   9  * This file is responsible for IEEE 1284 negotiation, and for handing
  10  * read/write requests to low-level drivers.
  11  *
  12  * Any part of this program may be used in documents licensed under
  13  * the GNU Free Documentation License, Version 1.1 or any later version
  14  * published by the Free Software Foundation.
  15  *
  16  * Various hacks, Fred Barnes <frmb2@ukc.ac.uk>, 04/2000
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/threads.h>
  22 #include <linux/parport.h>
  23 #include <linux/delay.h>
  24 #include <linux/kernel.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/timer.h>
  27 #include <linux/sched.h>
  28
  29 #undef DEBUG /* undef me for production */
  30
  31 #ifdef CONFIG_LP_CONSOLE
  32 #undef DEBUG /* Don't want a garbled console */
  33 #endif
  34
  35 #ifdef DEBUG
  36 #define DPRINTK(stuff...) printk (stuff)
  37 #else
  38 #define DPRINTK(stuff...)
  39 #endif
  40
  41 /* Make parport_wait_peripheral wake up.
  42  * It will be useful to call this from an interrupt handler. */
  43 static void parport_ieee1284_wakeup (struct parport *port)
  44 {
  45         up (&port->physport->ieee1284.irq);
  46 }
  47
  48 static struct parport *port_from_cookie[PARPORT_MAX];
  49 static void timeout_waiting_on_port (unsigned long cookie)
  50 {
  51         parport_ieee1284_wakeup (port_from_cookie[cookie % PARPORT_MAX]);
  52 }
  53
  54 /**
  55  *      parport_wait_event - wait for an event on a parallel port
  56  *      @port: port to wait on
  57  *      @timeout: time to wait (in jiffies)
  58  *
  59  *      This function waits for up to @timeout jiffies for an
  60  *      interrupt to occur on a parallel port.  If the port timeout is
  61  *      set to zero, it returns immediately.
  62  *
  63  *      If an interrupt occurs before the timeout period elapses, this
  64  *      function returns one immediately.  If it times out, it returns
  65  *      a value greater than zero.  An error code less than zero
  66  *      indicates an error (most likely a pending signal), and the
  67  *      calling code should finish what it's doing as soon as it can.
  68  */
  69
  70 int parport_wait_event (struct parport *port, signed long timeout)
  71 {
  72         int ret;
  73         struct timer_list timer;
  74
  75         if (!port->physport->cad->timeout)
  76                 /* Zero timeout is special, and we can't down() the
  77                    semaphore. */
  78                 return 1;
  79
  80         init_timer (&timer);
  81         timer.expires = jiffies + timeout;
  82         timer.function = timeout_waiting_on_port;
  83         port_from_cookie[port->number % PARPORT_MAX] = port;
  84         timer.data = port->number;
  85
  86         add_timer (&timer);
  87         ret = down_interruptible (&port->physport->ieee1284.irq);
  88         if (!del_timer (&timer) && !ret)
  89                 /* Timed out. */
  90                 ret = 1;
  91
  92         return ret;
  93 }
  94
  95 /**
  96  *      parport_poll_peripheral - poll status lines
  97  *      @port: port to watch
  98  *      @mask: status lines to watch
  99  *      @result: desired values of chosen status lines
 100  *      @usec: timeout
 101  *
 102  *      This function busy-waits until the masked status lines have
 103  *      the desired values, or until the timeout period elapses.  The
 104  *      @mask and @result parameters are bitmasks, with the bits
 105  *      defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
 106  *      and so on.
 107  *
 108  *      This function does not call schedule(); instead it busy-waits
 109  *      using udelay().  It currently has a resolution of 5usec.
 110  *
 111  *      If the status lines take on the desired values before the
 112  *      timeout period elapses, parport_poll_peripheral() returns zero
 113  *      immediately.  A zero return value greater than zero indicates
 114  *      a timeout.  An error code (less than zero) indicates an error,
 115  *      most likely a signal that arrived, and the caller should
 116  *      finish what it is doing as soon as possible.
 117 */
 118
 119 int parport_poll_peripheral(struct parport *port,
 120                             unsigned char mask,
 121                             unsigned char result,
 122                             int usec)
 123 {
 124         /* Zero return code is success, >0 is timeout. */
 125         int count = usec / 5 + 2;
 126         int i;
 127         unsigned char status;
 128         for (i = 0; i < count; i++) {
 129                 status = parport_read_status (port);
 130                 if ((status & mask) == result)
 131                         return 0;
 132                 if (signal_pending (current))
 133                         return -EINTR;
 134                 if (need_resched())
 135                         break;
 136                 if (i >= 2)
 137                         udelay (5);
 138         }
 139
 140         return 1;
 141 }
 142
 143 /**
 144  *      parport_wait_peripheral - wait for status lines to change in 35ms
 145  *      @port: port to watch
 146  *      @mask: status lines to watch
 147  *      @result: desired values of chosen status lines
 148  *
 149  *      This function waits until the masked status lines have the
 150  *      desired values, or until 35ms have elapsed (see IEEE 1284-1994
 151  *      page 24 to 25 for why this value in particular is hardcoded).
 152  *      The @mask and @result parameters are bitmasks, with the bits
 153  *      defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
 154  *      and so on.
 155  *
 156  *      The port is polled quickly to start off with, in anticipation
 157  *      of a fast response from the peripheral.  This fast polling
 158  *      time is configurable (using /proc), and defaults to 500usec.
 159  *      If the timeout for this port (see parport_set_timeout()) is
 160  *      zero, the fast polling time is 35ms, and this function does
 161  *      not call schedule().
 162  *
 163  *      If the timeout for this port is non-zero, after the fast
 164  *      polling fails it uses parport_wait_event() to wait for up to
 165  *      10ms, waking up if an interrupt occurs.
 166  */
 167
 168 int parport_wait_peripheral(struct parport *port,
 169                             unsigned char mask,
 170                             unsigned char result)
 171 {
 172         int ret;
 173         int usec;
 174         unsigned long deadline;
 175         unsigned char status;
 176
 177         usec = port->physport->spintime; /* usecs of fast polling */
 178         if (!port->physport->cad->timeout)
 179                 /* A zero timeout is "special": busy wait for the
 180                    entire 35ms. */
 181                 usec = 35000;
 182
 183         /* Fast polling.
 184          *
 185          * This should be adjustable.
 186          * How about making a note (in the device structure) of how long
 187          * it takes, so we know for next time?
 188          */
 189         ret = parport_poll_peripheral (port, mask, result, usec);
 190         if (ret != 1)
 191                 return ret;
 192
 193         if (!port->physport->cad->timeout)
 194                 /* We may be in an interrupt handler, so we can't poll
 195                  * slowly anyway. */
 196                 return 1;
 197
 198         /* 40ms of slow polling. */
 199         deadline = jiffies + msecs_to_jiffies(40);
 200         while (time_before (jiffies, deadline)) {
 201                 int ret;
 202
 203                 if (signal_pending (current))
 204                         return -EINTR;
 205
 206                 /* Wait for 10ms (or until an interrupt occurs if
 207                  * the handler is set) */
 208                 if ((ret = parport_wait_event (port, msecs_to_jiffies(10))) < 0)
 209                         return ret;
 210
 211                 status = parport_read_status (port);
 212                 if ((status & mask) == result)
 213                         return 0;
 214
 215                 if (!ret) {
 216                         /* parport_wait_event didn't time out, but the
 217                          * peripheral wasn't actually ready either.
 218                          * Wait for another 10ms. */
 219                         schedule_timeout_interruptible(msecs_to_jiffies(10));
 220                 }
 221         }
 222
 223         return 1;
 224 }
 225
 226 #ifdef CONFIG_PARPORT_1284
 227 /* Terminate a negotiated mode. */
 228 static void parport_ieee1284_terminate (struct parport *port)
 229 {
 230         int r;
 231         port = port->physport;
 232
 233         /* EPP terminates differently. */
 234         switch (port->ieee1284.mode) {
 235         case IEEE1284_MODE_EPP:
 236         case IEEE1284_MODE_EPPSL:
 237         case IEEE1284_MODE_EPPSWE:
 238                 /* Terminate from EPP mode. */
 239
 240                 /* Event 68: Set nInit low */
 241                 parport_frob_control (port, PARPORT_CONTROL_INIT, 0);
 242                 udelay (50);
 243
 244                 /* Event 69: Set nInit high, nSelectIn low */
 245                 parport_frob_control (port,
 246                                       PARPORT_CONTROL_SELECT
 247                                       | PARPORT_CONTROL_INIT,
 248                                       PARPORT_CONTROL_SELECT
 249                                       | PARPORT_CONTROL_INIT);
 250                 break;
 251
 252         case IEEE1284_MODE_ECP:
 253         case IEEE1284_MODE_ECPRLE:
 254         case IEEE1284_MODE_ECPSWE:
 255                 /* In ECP we can only terminate from fwd idle phase. */
 256                 if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) {
 257                         /* Event 47: Set nInit high */
 258                         parport_frob_control (port,
 259                                               PARPORT_CONTROL_INIT
 260                                               | PARPORT_CONTROL_AUTOFD,
 261                                               PARPORT_CONTROL_INIT
 262                                               | PARPORT_CONTROL_AUTOFD);
 263
 264                         /* Event 49: PError goes high */
 265                         r = parport_wait_peripheral (port,
 266                                                      PARPORT_STATUS_PAPEROUT,
 267                                                      PARPORT_STATUS_PAPEROUT);
 268                         if (r)
 269                                 DPRINTK (KERN_INFO "%s: Timeout at event 49\n",
 270                                          port->name);
 271
 272                         parport_data_forward (port);
 273                         DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
 274                                  port->name);
 275                         port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 276                 }
 277
 278                 /* fall-though.. */
 279
 280         default:
 281                 /* Terminate from all other modes. */
 282
 283                 /* Event 22: Set nSelectIn low, nAutoFd high */
 284                 parport_frob_control (port,
 285                                       PARPORT_CONTROL_SELECT
 286                                       | PARPORT_CONTROL_AUTOFD,
 287                                       PARPORT_CONTROL_SELECT);
 288
 289                 /* Event 24: nAck goes low */
 290                 r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0);
 291                 if (r)
 292                         DPRINTK (KERN_INFO "%s: Timeout at event 24\n",
 293                                  port->name);
 294
 295                 /* Event 25: Set nAutoFd low */
 296                 parport_frob_control (port,
 297                                       PARPORT_CONTROL_AUTOFD,
 298                                       PARPORT_CONTROL_AUTOFD);
 299
 300                 /* Event 27: nAck goes high */
 301                 r = parport_wait_peripheral (port,
 302                                              PARPORT_STATUS_ACK,
 303                                              PARPORT_STATUS_ACK);
 304                 if (r)
 305                         DPRINTK (KERN_INFO "%s: Timeout at event 27\n",
 306                                  port->name);
 307
 308                 /* Event 29: Set nAutoFd high */
 309                 parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
 310         }
 311
 312         port->ieee1284.mode = IEEE1284_MODE_COMPAT;
 313         port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 314
 315         DPRINTK (KERN_DEBUG "%s: In compatibility (forward idle) mode\n",
 316                  port->name);
 317 }
 318 #endif /* IEEE1284 support */
 319
 320 /**
 321  *      parport_negotiate - negotiate an IEEE 1284 mode
 322  *      @port: port to use
 323  *      @mode: mode to negotiate to
 324  *
 325  *      Use this to negotiate to a particular IEEE 1284 transfer mode.
 326  *      The @mode parameter should be one of the constants in
 327  *      parport.h starting %IEEE1284_MODE_xxx.
 328  *
 329  *      The return value is 0 if the peripheral has accepted the
 330  *      negotiation to the mode specified, -1 if the peripheral is not
 331  *      IEEE 1284 compliant (or not present), or 1 if the peripheral
 332  *      has rejected the negotiation.
 333  */
 334
 335 int parport_negotiate (struct parport *port, int mode)
 336 {
 337 #ifndef CONFIG_PARPORT_1284
 338         if (mode == IEEE1284_MODE_COMPAT)
 339                 return 0;
 340         printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
 341         return -1;
 342 #else
 343         int m = mode & ~IEEE1284_ADDR;
 344         int r;
 345         unsigned char xflag;
 346
 347         port = port->physport;
 348
 349         /* Is there anything to do? */
 350         if (port->ieee1284.mode == mode)
 351                 return 0;
 352
 353         /* Is the difference just an address-or-not bit? */
 354         if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){
 355                 port->ieee1284.mode = mode;
 356                 return 0;
 357         }
 358
 359         /* Go to compability forward idle mode */
 360         if (port->ieee1284.mode != IEEE1284_MODE_COMPAT)
 361                 parport_ieee1284_terminate (port);
 362
 363         if (mode == IEEE1284_MODE_COMPAT)
 364                 /* Compatibility mode: no negotiation. */
 365                 return 0;
 366
 367         switch (mode) {
 368         case IEEE1284_MODE_ECPSWE:
 369                 m = IEEE1284_MODE_ECP;
 370                 break;
 371         case IEEE1284_MODE_EPPSL:
 372         case IEEE1284_MODE_EPPSWE:
 373                 m = IEEE1284_MODE_EPP;
 374                 break;
 375         case IEEE1284_MODE_BECP:
 376                 return -ENOSYS; /* FIXME (implement BECP) */
 377         }
 378
 379         if (mode & IEEE1284_EXT_LINK)
 380                 m = 1<<7; /* request extensibility link */
 381
 382         port->ieee1284.phase = IEEE1284_PH_NEGOTIATION;
 383
 384         /* Start off with nStrobe and nAutoFd high, and nSelectIn low */
 385         parport_frob_control (port,
 386                               PARPORT_CONTROL_STROBE
 387                               | PARPORT_CONTROL_AUTOFD
 388                               | PARPORT_CONTROL_SELECT,
 389                               PARPORT_CONTROL_SELECT);
 390         udelay(1);
 391
 392         /* Event 0: Set data */
 393         parport_data_forward (port);
 394         parport_write_data (port, m);
 395         udelay (400); /* Shouldn't need to wait this long. */
 396
 397         /* Event 1: Set nSelectIn high, nAutoFd low */
 398         parport_frob_control (port,
 399                               PARPORT_CONTROL_SELECT
 400                               | PARPORT_CONTROL_AUTOFD,
 401                               PARPORT_CONTROL_AUTOFD);
 402
 403         /* Event 2: PError, Select, nFault go high, nAck goes low */
 404         if (parport_wait_peripheral (port,
 405                                      PARPORT_STATUS_ERROR
 406                                      | PARPORT_STATUS_SELECT
 407                                      | PARPORT_STATUS_PAPEROUT
 408                                      | PARPORT_STATUS_ACK,
 409                                      PARPORT_STATUS_ERROR
 410                                      | PARPORT_STATUS_SELECT
 411                                      | PARPORT_STATUS_PAPEROUT)) {
 412                 /* Timeout */
 413                 parport_frob_control (port,
 414                                       PARPORT_CONTROL_SELECT
 415                                       | PARPORT_CONTROL_AUTOFD,
 416                                       PARPORT_CONTROL_SELECT);
 417                 DPRINTK (KERN_DEBUG
 418                          "%s: Peripheral not IEEE1284 compliant (0x%02X)\n",
 419                          port->name, parport_read_status (port));
 420                 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 421                 return -1; /* Not IEEE1284 compliant */
 422         }
 423
 424         /* Event 3: Set nStrobe low */
 425         parport_frob_control (port,
 426                               PARPORT_CONTROL_STROBE,
 427                               PARPORT_CONTROL_STROBE);
 428
 429         /* Event 4: Set nStrobe and nAutoFd high */
 430         udelay (5);
 431         parport_frob_control (port,
 432                               PARPORT_CONTROL_STROBE
 433                               | PARPORT_CONTROL_AUTOFD,
 434                               0);
 435
 436         /* Event 6: nAck goes high */
 437         if (parport_wait_peripheral (port,
 438                                      PARPORT_STATUS_ACK,
 439                                      PARPORT_STATUS_ACK)) {
 440                 /* This shouldn't really happen with a compliant device. */
 441                 DPRINTK (KERN_DEBUG
 442                          "%s: Mode 0x%02x not supported? (0x%02x)\n",
 443                          port->name, mode, port->ops->read_status (port));
 444                 parport_ieee1284_terminate (port);
 445                 return 1;
 446         }
 447
 448         xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
 449
 450         /* xflag should be high for all modes other than nibble (0). */
 451         if (mode && !xflag) {
 452                 /* Mode not supported. */
 453                 DPRINTK (KERN_DEBUG "%s: Mode 0x%02x rejected by peripheral\n",
 454                          port->name, mode);
 455                 parport_ieee1284_terminate (port);
 456                 return 1;
 457         }
 458
 459         /* More to do if we've requested extensibility link. */
 460         if (mode & IEEE1284_EXT_LINK) {
 461                 m = mode & 0x7f;
 462                 udelay (1);
 463                 parport_write_data (port, m);
 464                 udelay (1);
 465
 466                 /* Event 51: Set nStrobe low */
 467                 parport_frob_control (port,
 468                                       PARPORT_CONTROL_STROBE,
 469                                       PARPORT_CONTROL_STROBE);
 470
 471                 /* Event 52: nAck goes low */
 472                 if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0)) {
 473                         /* This peripheral is _very_ slow. */
 474                         DPRINTK (KERN_DEBUG
 475                                  "%s: Event 52 didn't happen\n",
 476                                  port->name);
 477                         parport_ieee1284_terminate (port);
 478                         return 1;
 479                 }
 480
 481                 /* Event 53: Set nStrobe high */
 482                 parport_frob_control (port,
 483                                       PARPORT_CONTROL_STROBE,
 484                                       0);
 485
 486                 /* Event 55: nAck goes high */
 487                 if (parport_wait_peripheral (port,
 488                                              PARPORT_STATUS_ACK,
 489                                              PARPORT_STATUS_ACK)) {
 490                         /* This shouldn't really happen with a compliant
 491                          * device. */
 492                         DPRINTK (KERN_DEBUG
 493                                  "%s: Mode 0x%02x not supported? (0x%02x)\n",
 494                                  port->name, mode,
 495                                  port->ops->read_status (port));
 496                         parport_ieee1284_terminate (port);
 497                         return 1;
 498                 }
 499
 500                 /* Event 54: Peripheral sets XFlag to reflect support */
 501                 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
 502
 503                 /* xflag should be high. */
 504                 if (!xflag) {
 505                         /* Extended mode not supported. */
 506                         DPRINTK (KERN_DEBUG "%s: Extended mode 0x%02x not "
 507                                  "supported\n", port->name, mode);
 508                         parport_ieee1284_terminate (port);
 509                         return 1;
 510                 }
 511
 512                 /* Any further setup is left to the caller. */
 513         }
 514
 515         /* Mode is supported */
 516         DPRINTK (KERN_DEBUG "%s: In mode 0x%02x\n", port->name, mode);
 517         port->ieee1284.mode = mode;
 518
 519         /* But ECP is special */
 520         if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) {
 521                 port->ieee1284.phase = IEEE1284_PH_ECP_SETUP;
 522
 523                 /* Event 30: Set nAutoFd low */
 524                 parport_frob_control (port,
 525                                       PARPORT_CONTROL_AUTOFD,
 526                                       PARPORT_CONTROL_AUTOFD);
 527
 528                 /* Event 31: PError goes high. */
 529                 r = parport_wait_peripheral (port,
 530                                              PARPORT_STATUS_PAPEROUT,
 531                                              PARPORT_STATUS_PAPEROUT);
 532                 if (r) {
 533                         DPRINTK (KERN_INFO "%s: Timeout at event 31\n",
 534                                 port->name);
 535                 }
 536
 537                 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 538                 DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
 539                          port->name);
 540         } else switch (mode) {
 541         case IEEE1284_MODE_NIBBLE:
 542         case IEEE1284_MODE_BYTE:
 543                 port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
 544                 break;
 545         default:
 546                 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
 547         }
 548
 549
 550         return 0;
 551 #endif /* IEEE1284 support */
 552 }
 553
 554 /* Acknowledge that the peripheral has data available.
 555  * Events 18-20, in order to get from Reverse Idle phase
 556  * to Host Busy Data Available.
 557  * This will most likely be called from an interrupt.
 558  * Returns zero if data was available.
 559  */
 560 #ifdef CONFIG_PARPORT_1284
 561 static int parport_ieee1284_ack_data_avail (struct parport *port)
 562 {
 563         if (parport_read_status (port) & PARPORT_STATUS_ERROR)
 564                 /* Event 18 didn't happen. */
 565                 return -1;
 566
 567         /* Event 20: nAutoFd goes high. */
 568         port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
 569         port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
 570         return 0;
 571 }
 572 #endif /* IEEE1284 support */
 573
 574 /* Handle an interrupt. */
 575 void parport_ieee1284_interrupt (int which, void *handle, struct pt_regs *regs)
 576 {
 577         struct parport *port = handle;
 578         parport_ieee1284_wakeup (port);
 579
 580 #ifdef CONFIG_PARPORT_1284
 581         if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) {
 582                 /* An interrupt in this phase means that data
 583                  * is now available. */
 584                 DPRINTK (KERN_DEBUG "%s: Data available\n", port->name);
 585                 parport_ieee1284_ack_data_avail (port);
 586         }
 587 #endif /* IEEE1284 support */
 588 }
 589
 590 /**
 591  *      parport_write - write a block of data to a parallel port
 592  *      @port: port to write to
 593  *      @buffer: data buffer (in kernel space)
 594  *      @len: number of bytes of data to transfer
 595  *
 596  *      This will write up to @len bytes of @buffer to the port
 597  *      specified, using the IEEE 1284 transfer mode most recently
 598  *      negotiated to (using parport_negotiate()), as long as that
 599  *      mode supports forward transfers (host to peripheral).
 600  *
 601  *      It is the caller's responsibility to ensure that the first
 602  *      @len bytes of @buffer are valid.
 603  *
 604  *      This function returns the number of bytes transferred (if zero
 605  *      or positive), or else an error code.
 606  */
 607
 608 ssize_t parport_write (struct parport *port, const void *buffer, size_t len)
 609 {
 610 #ifndef CONFIG_PARPORT_1284
 611         return port->ops->compat_write_data (port, buffer, len, 0);
 612 #else
 613         ssize_t retval;
 614         int mode = port->ieee1284.mode;
 615         int addr = mode & IEEE1284_ADDR;
 616         size_t (*fn) (struct parport *, const void *, size_t, int);
 617
 618         /* Ignore the device-ID-request bit and the address bit. */
 619         mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 620
 621         /* Use the mode we're in. */
 622         switch (mode) {
 623         case IEEE1284_MODE_NIBBLE:
 624         case IEEE1284_MODE_BYTE:
 625                 parport_negotiate (port, IEEE1284_MODE_COMPAT);
 626         case IEEE1284_MODE_COMPAT:
 627                 DPRINTK (KERN_DEBUG "%s: Using compatibility mode\n",
 628                          port->name);
 629                 fn = port->ops->compat_write_data;
 630                 break;
 631
 632         case IEEE1284_MODE_EPP:
 633                 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
 634                 if (addr) {
 635                         fn = port->ops->epp_write_addr;
 636                 } else {
 637                         fn = port->ops->epp_write_data;
 638                 }
 639                 break;
 640         case IEEE1284_MODE_EPPSWE:
 641                 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
 642                         port->name);
 643                 if (addr) {
 644                         fn = parport_ieee1284_epp_write_addr;
 645                 } else {
 646                         fn = parport_ieee1284_epp_write_data;
 647                 }
 648                 break;
 649         case IEEE1284_MODE_ECP:
 650         case IEEE1284_MODE_ECPRLE:
 651                 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
 652                 if (addr) {
 653                         fn = port->ops->ecp_write_addr;
 654                 } else {
 655                         fn = port->ops->ecp_write_data;
 656                 }
 657                 break;
 658
 659         case IEEE1284_MODE_ECPSWE:
 660                 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
 661                          port->name);
 662                 /* The caller has specified that it must be emulated,
 663                  * even if we have ECP hardware! */
 664                 if (addr) {
 665                         fn = parport_ieee1284_ecp_write_addr;
 666                 } else {
 667                         fn = parport_ieee1284_ecp_write_data;
 668                 }
 669                 break;
 670
 671         default:
 672                 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
 673                         port->ieee1284.mode);
 674                 return -ENOSYS;
 675         }
 676
 677         retval = (*fn) (port, buffer, len, 0);
 678         DPRINTK (KERN_DEBUG "%s: wrote %d/%d bytes\n", port->name, retval, len);
 679         return retval;
 680 #endif /* IEEE1284 support */
 681 }
 682
 683 /**
 684  *      parport_read - read a block of data from a parallel port
 685  *      @port: port to read from
 686  *      @buffer: data buffer (in kernel space)
 687  *      @len: number of bytes of data to transfer
 688  *
 689  *      This will read up to @len bytes of @buffer to the port
 690  *      specified, using the IEEE 1284 transfer mode most recently
 691  *      negotiated to (using parport_negotiate()), as long as that
 692  *      mode supports reverse transfers (peripheral to host).
 693  *
 694  *      It is the caller's responsibility to ensure that the first
 695  *      @len bytes of @buffer are available to write to.
 696  *
 697  *      This function returns the number of bytes transferred (if zero
 698  *      or positive), or else an error code.
 699  */
 700
 701 ssize_t parport_read (struct parport *port, void *buffer, size_t len)
 702 {
 703 #ifndef CONFIG_PARPORT_1284
 704         printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
 705         return -ENODEV;
 706 #else
 707         int mode = port->physport->ieee1284.mode;
 708         int addr = mode & IEEE1284_ADDR;
 709         size_t (*fn) (struct parport *, void *, size_t, int);
 710
 711         /* Ignore the device-ID-request bit and the address bit. */
 712         mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 713
 714         /* Use the mode we're in. */
 715         switch (mode) {
 716         case IEEE1284_MODE_COMPAT:
 717                 /* if we can tri-state use BYTE mode instead of NIBBLE mode,
 718                  * if that fails, revert to NIBBLE mode -- ought to store somewhere
 719                  * the device's ability to do BYTE mode reverse transfers, so we don't
 720                  * end up needlessly calling negotiate(BYTE) repeately..  (fb)
 721                  */
 722                 if ((port->physport->modes & PARPORT_MODE_TRISTATE) &&
 723                     !parport_negotiate (port, IEEE1284_MODE_BYTE)) {
 724                         /* got into BYTE mode OK */
 725                         DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
 726                         fn = port->ops->byte_read_data;
 727                         break;
 728                 }
 729                 if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) {
 730                         return -EIO;
 731                 }
 732                 /* fall through to NIBBLE */
 733         case IEEE1284_MODE_NIBBLE:
 734                 DPRINTK (KERN_DEBUG "%s: Using nibble mode\n", port->name);
 735                 fn = port->ops->nibble_read_data;
 736                 break;
 737
 738         case IEEE1284_MODE_BYTE:
 739                 DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
 740                 fn = port->ops->byte_read_data;
 741                 break;
 742
 743         case IEEE1284_MODE_EPP:
 744                 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
 745                 if (addr) {
 746                         fn = port->ops->epp_read_addr;
 747                 } else {
 748                         fn = port->ops->epp_read_data;
 749                 }
 750                 break;
 751         case IEEE1284_MODE_EPPSWE:
 752                 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
 753                         port->name);
 754                 if (addr) {
 755                         fn = parport_ieee1284_epp_read_addr;
 756                 } else {
 757                         fn = parport_ieee1284_epp_read_data;
 758                 }
 759                 break;
 760         case IEEE1284_MODE_ECP:
 761         case IEEE1284_MODE_ECPRLE:
 762                 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
 763                 fn = port->ops->ecp_read_data;
 764                 break;
 765
 766         case IEEE1284_MODE_ECPSWE:
 767                 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
 768                          port->name);
 769                 fn = parport_ieee1284_ecp_read_data;
 770                 break;
 771
 772         default:
 773                 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
 774                          port->physport->ieee1284.mode);
 775                 return -ENOSYS;
 776         }
 777
 778         return (*fn) (port, buffer, len, 0);
 779 #endif /* IEEE1284 support */
 780 }
 781
 782 /**
 783  *      parport_set_timeout - set the inactivity timeout for a device
 784  *      @dev: device on a port
 785  *      @inactivity: inactivity timeout (in jiffies)
 786  *
 787  *      This sets the inactivity timeout for a particular device on a
 788  *      port.  This affects functions like parport_wait_peripheral().
 789  *      The special value 0 means not to call schedule() while dealing
 790  *      with this device.
 791  *
 792  *      The return value is the previous inactivity timeout.
 793  *
 794  *      Any callers of parport_wait_event() for this device are woken
 795  *      up.
 796  */
 797
 798 long parport_set_timeout (struct pardevice *dev, long inactivity)
 799 {
 800         long int old = dev->timeout;
 801
 802         dev->timeout = inactivity;
 803
 804         if (dev->port->physport->cad == dev)
 805                 parport_ieee1284_wakeup (dev->port);
 806
 807         return old;
 808 }
 809
 810 /* Exported symbols for modules. */
 811
 812 EXPORT_SYMBOL(parport_negotiate);
 813 EXPORT_SYMBOL(parport_write);
 814 EXPORT_SYMBOL(parport_read);
 815 EXPORT_SYMBOL(parport_wait_peripheral);
 816 EXPORT_SYMBOL(parport_wait_event);
 817 EXPORT_SYMBOL(parport_set_timeout);
 818 EXPORT_SYMBOL(parport_ieee1284_interrupt);