drivers/char/ppdev.c

   1 /*
   2  * linux/drivers/char/ppdev.c
   3  *
   4  * This is the code behind /dev/parport* -- it allows a user-space
   5  * application to use the parport subsystem.
   6  *
   7  * Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  *
  14  * A /dev/parportx device node represents an arbitrary device
  15  * on port 'x'.  The following operations are possible:
  16  *
  17  * open         do nothing, set up default IEEE 1284 protocol to be COMPAT
  18  * close        release port and unregister device (if necessary)
  19  * ioctl
  20  *   EXCL       register device exclusively (may fail)
  21  *   CLAIM      (register device first time) parport_claim_or_block
  22  *   RELEASE    parport_release
  23  *   SETMODE    set the IEEE 1284 protocol to use for read/write
  24  *   SETPHASE   set the IEEE 1284 phase of a particular mode.  Not to be
  25  *              confused with ioctl(fd, SETPHASER, &stun). ;-)
  26  *   DATADIR    data_forward / data_reverse
  27  *   WDATA      write_data
  28  *   RDATA      read_data
  29  *   WCONTROL   write_control
  30  *   RCONTROL   read_control
  31  *   FCONTROL   frob_control
  32  *   RSTATUS    read_status
  33  *   NEGOT      parport_negotiate
  34  *   YIELD      parport_yield_blocking
  35  *   WCTLONIRQ  on interrupt, set control lines
  36  *   CLRIRQ     clear (and return) interrupt count
  37  *   SETTIME    sets device timeout (struct timeval)
  38  *   GETTIME    gets device timeout (struct timeval)
  39  *   GETMODES   gets hardware supported modes (unsigned int)
  40  *   GETMODE    gets the current IEEE1284 mode
  41  *   GETPHASE   gets the current IEEE1284 phase
  42  *   GETFLAGS   gets current (user-visible) flags
  43  *   SETFLAGS   sets current (user-visible) flags
  44  * read/write   read or write in current IEEE 1284 protocol
  45  * select       wait for interrupt (in readfds)
  46  *
  47  * Changes:
  48  * Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
  49  *
  50  * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
  51  * - On error, copy_from_user and copy_to_user do not return -EFAULT,
  52  *   They return the positive number of bytes *not* copied due to address
  53  *   space errors.
  54  *
  55  * Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
  56  * Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
  57  */
  58
  59 #include <linux/module.h>
  60 #include <linux/init.h>
  61 #include <linux/sched/signal.h>
  62 #include <linux/device.h>
  63 #include <linux/ioctl.h>
  64 #include <linux/parport.h>
  65 #include <linux/ctype.h>
  66 #include <linux/poll.h>
  67 #include <linux/slab.h>
  68 #include <linux/major.h>
  69 #include <linux/ppdev.h>
  70 #include <linux/mutex.h>
  71 #include <linux/uaccess.h>
  72 #include <linux/compat.h>
  73
  74 #define PP_VERSION "ppdev: user-space parallel port driver"
  75 #define CHRDEV "ppdev"
  76
  77 struct pp_struct {
  78         struct pardevice *pdev;
  79         wait_queue_head_t irq_wait;
  80         atomic_t irqc;
  81         unsigned int flags;
  82         int irqresponse;
  83         unsigned char irqctl;
  84         struct ieee1284_info state;
  85         struct ieee1284_info saved_state;
  86         long default_inactivity;
  87         int index;
  88 };
  89
  90 /* should we use PARDEVICE_MAX here? */
  91 static struct device *devices[PARPORT_MAX];
  92
  93 static DEFINE_IDA(ida_index);
  94
  95 /* pp_struct.flags bitfields */
  96 #define PP_CLAIMED    (1<<0)
  97 #define PP_EXCL       (1<<1)
  98
  99 /* Other constants */
 100 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
 101 #define PP_BUFFER_SIZE 1024
 102 #define PARDEVICE_MAX 8
 103
 104 static DEFINE_MUTEX(pp_do_mutex);
 105
 106 /* define fixed sized ioctl cmd for y2038 migration */
 107 #define PPGETTIME32     _IOR(PP_IOCTL, 0x95, s32[2])
 108 #define PPSETTIME32     _IOW(PP_IOCTL, 0x96, s32[2])
 109 #define PPGETTIME64     _IOR(PP_IOCTL, 0x95, s64[2])
 110 #define PPSETTIME64     _IOW(PP_IOCTL, 0x96, s64[2])
 111
 112 static inline void pp_enable_irq(struct pp_struct *pp)
 113 {
 114         struct parport *port = pp->pdev->port;
 115
 116         port->ops->enable_irq(port);
 117 }
 118
 119 static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
 120                        loff_t *ppos)
 121 {
 122         unsigned int minor = iminor(file_inode(file));
 123         struct pp_struct *pp = file->private_data;
 124         char *kbuffer;
 125         ssize_t bytes_read = 0;
 126         struct parport *pport;
 127         int mode;
 128
 129         if (!(pp->flags & PP_CLAIMED)) {
 130                 /* Don't have the port claimed */
 131                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 132                 return -EINVAL;
 133         }
 134
 135         /* Trivial case. */
 136         if (count == 0)
 137                 return 0;
 138
 139         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 140         if (!kbuffer)
 141                 return -ENOMEM;
 142         pport = pp->pdev->port;
 143         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 144
 145         parport_set_timeout(pp->pdev,
 146                             (file->f_flags & O_NONBLOCK) ?
 147                             PARPORT_INACTIVITY_O_NONBLOCK :
 148                             pp->default_inactivity);
 149
 150         while (bytes_read == 0) {
 151                 ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
 152
 153                 if (mode == IEEE1284_MODE_EPP) {
 154                         /* various specials for EPP mode */
 155                         int flags = 0;
 156                         size_t (*fn)(struct parport *, void *, size_t, int);
 157
 158                         if (pp->flags & PP_W91284PIC)
 159                                 flags |= PARPORT_W91284PIC;
 160                         if (pp->flags & PP_FASTREAD)
 161                                 flags |= PARPORT_EPP_FAST;
 162                         if (pport->ieee1284.mode & IEEE1284_ADDR)
 163                                 fn = pport->ops->epp_read_addr;
 164                         else
 165                                 fn = pport->ops->epp_read_data;
 166                         bytes_read = (*fn)(pport, kbuffer, need, flags);
 167                 } else {
 168                         bytes_read = parport_read(pport, kbuffer, need);
 169                 }
 170
 171                 if (bytes_read != 0)
 172                         break;
 173
 174                 if (file->f_flags & O_NONBLOCK) {
 175                         bytes_read = -EAGAIN;
 176                         break;
 177                 }
 178
 179                 if (signal_pending(current)) {
 180                         bytes_read = -ERESTARTSYS;
 181                         break;
 182                 }
 183
 184                 cond_resched();
 185         }
 186
 187         parport_set_timeout(pp->pdev, pp->default_inactivity);
 188
 189         if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
 190                 bytes_read = -EFAULT;
 191
 192         kfree(kbuffer);
 193         pp_enable_irq(pp);
 194         return bytes_read;
 195 }
 196
 197 static ssize_t pp_write(struct file *file, const char __user *buf,
 198                         size_t count, loff_t *ppos)
 199 {
 200         unsigned int minor = iminor(file_inode(file));
 201         struct pp_struct *pp = file->private_data;
 202         char *kbuffer;
 203         ssize_t bytes_written = 0;
 204         ssize_t wrote;
 205         int mode;
 206         struct parport *pport;
 207
 208         if (!(pp->flags & PP_CLAIMED)) {
 209                 /* Don't have the port claimed */
 210                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 211                 return -EINVAL;
 212         }
 213
 214         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 215         if (!kbuffer)
 216                 return -ENOMEM;
 217
 218         pport = pp->pdev->port;
 219         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 220
 221         parport_set_timeout(pp->pdev,
 222                             (file->f_flags & O_NONBLOCK) ?
 223                             PARPORT_INACTIVITY_O_NONBLOCK :
 224                             pp->default_inactivity);
 225
 226         while (bytes_written < count) {
 227                 ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
 228
 229                 if (copy_from_user(kbuffer, buf + bytes_written, n)) {
 230                         bytes_written = -EFAULT;
 231                         break;
 232                 }
 233
 234                 if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
 235                         /* do a fast EPP write */
 236                         if (pport->ieee1284.mode & IEEE1284_ADDR) {
 237                                 wrote = pport->ops->epp_write_addr(pport,
 238                                         kbuffer, n, PARPORT_EPP_FAST);
 239                         } else {
 240                                 wrote = pport->ops->epp_write_data(pport,
 241                                         kbuffer, n, PARPORT_EPP_FAST);
 242                         }
 243                 } else {
 244                         wrote = parport_write(pp->pdev->port, kbuffer, n);
 245                 }
 246
 247                 if (wrote <= 0) {
 248                         if (!bytes_written)
 249                                 bytes_written = wrote;
 250                         break;
 251                 }
 252
 253                 bytes_written += wrote;
 254
 255                 if (file->f_flags & O_NONBLOCK) {
 256                         if (!bytes_written)
 257                                 bytes_written = -EAGAIN;
 258                         break;
 259                 }
 260
 261                 if (signal_pending(current))
 262                         break;
 263
 264                 cond_resched();
 265         }
 266
 267         parport_set_timeout(pp->pdev, pp->default_inactivity);
 268
 269         kfree(kbuffer);
 270         pp_enable_irq(pp);
 271         return bytes_written;
 272 }
 273
 274 static void pp_irq(void *private)
 275 {
 276         struct pp_struct *pp = private;
 277
 278         if (pp->irqresponse) {
 279                 parport_write_control(pp->pdev->port, pp->irqctl);
 280                 pp->irqresponse = 0;
 281         }
 282
 283         atomic_inc(&pp->irqc);
 284         wake_up_interruptible(&pp->irq_wait);
 285 }
 286
 287 static int register_device(int minor, struct pp_struct *pp)
 288 {
 289         struct parport *port;
 290         struct pardevice *pdev = NULL;
 291         char *name;
 292         struct pardev_cb ppdev_cb;
 293         int rc = 0, index;
 294
 295         name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
 296         if (name == NULL)
 297                 return -ENOMEM;
 298
 299         port = parport_find_number(minor);
 300         if (!port) {
 301                 pr_warn("%s: no associated port!\n", name);
 302                 rc = -ENXIO;
 303                 goto err;
 304         }
 305
 306         index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
 307         memset(&ppdev_cb, 0, sizeof(ppdev_cb));
 308         ppdev_cb.irq_func = pp_irq;
 309         ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
 310         ppdev_cb.private = pp;
 311         pdev = parport_register_dev_model(port, name, &ppdev_cb, index);
 312         parport_put_port(port);
 313
 314         if (!pdev) {
 315                 pr_warn("%s: failed to register device!\n", name);
 316                 rc = -ENXIO;
 317                 ida_simple_remove(&ida_index, index);
 318                 goto err;
 319         }
 320
 321         pp->pdev = pdev;
 322         pp->index = index;
 323         dev_dbg(&pdev->dev, "registered pardevice\n");
 324 err:
 325         kfree(name);
 326         return rc;
 327 }
 328
 329 static enum ieee1284_phase init_phase(int mode)
 330 {
 331         switch (mode & ~(IEEE1284_DEVICEID
 332                          | IEEE1284_ADDR)) {
 333         case IEEE1284_MODE_NIBBLE:
 334         case IEEE1284_MODE_BYTE:
 335                 return IEEE1284_PH_REV_IDLE;
 336         }
 337         return IEEE1284_PH_FWD_IDLE;
 338 }
 339
 340 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
 341 {
 342         long to_jiffies;
 343
 344         if ((tv_sec < 0) || (tv_usec < 0))
 345                 return -EINVAL;
 346
 347         to_jiffies = usecs_to_jiffies(tv_usec);
 348         to_jiffies += tv_sec * HZ;
 349         if (to_jiffies <= 0)
 350                 return -EINVAL;
 351
 352         pdev->timeout = to_jiffies;
 353         return 0;
 354 }
 355
 356 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 357 {
 358         unsigned int minor = iminor(file_inode(file));
 359         struct pp_struct *pp = file->private_data;
 360         struct parport *port;
 361         void __user *argp = (void __user *)arg;
 362
 363         /* First handle the cases that don't take arguments. */
 364         switch (cmd) {
 365         case PPCLAIM:
 366             {
 367                 struct ieee1284_info *info;
 368                 int ret;
 369
 370                 if (pp->flags & PP_CLAIMED) {
 371                         dev_dbg(&pp->pdev->dev, "you've already got it!\n");
 372                         return -EINVAL;
 373                 }
 374
 375                 /* Deferred device registration. */
 376                 if (!pp->pdev) {
 377                         int err = register_device(minor, pp);
 378
 379                         if (err)
 380                                 return err;
 381                 }
 382
 383                 ret = parport_claim_or_block(pp->pdev);
 384                 if (ret < 0)
 385                         return ret;
 386
 387                 pp->flags |= PP_CLAIMED;
 388
 389                 /* For interrupt-reporting to work, we need to be
 390                  * informed of each interrupt. */
 391                 pp_enable_irq(pp);
 392
 393                 /* We may need to fix up the state machine. */
 394                 info = &pp->pdev->port->ieee1284;
 395                 pp->saved_state.mode = info->mode;
 396                 pp->saved_state.phase = info->phase;
 397                 info->mode = pp->state.mode;
 398                 info->phase = pp->state.phase;
 399                 pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
 400                 parport_set_timeout(pp->pdev, pp->default_inactivity);
 401
 402                 return 0;
 403             }
 404         case PPEXCL:
 405                 if (pp->pdev) {
 406                         dev_dbg(&pp->pdev->dev,
 407                                 "too late for PPEXCL; already registered\n");
 408                         if (pp->flags & PP_EXCL)
 409                                 /* But it's not really an error. */
 410                                 return 0;
 411                         /* There's no chance of making the driver happy. */
 412                         return -EINVAL;
 413                 }
 414
 415                 /* Just remember to register the device exclusively
 416                  * when we finally do the registration. */
 417                 pp->flags |= PP_EXCL;
 418                 return 0;
 419         case PPSETMODE:
 420             {
 421                 int mode;
 422
 423                 if (copy_from_user(&mode, argp, sizeof(mode)))
 424                         return -EFAULT;
 425                 /* FIXME: validate mode */
 426                 pp->state.mode = mode;
 427                 pp->state.phase = init_phase(mode);
 428
 429                 if (pp->flags & PP_CLAIMED) {
 430                         pp->pdev->port->ieee1284.mode = mode;
 431                         pp->pdev->port->ieee1284.phase = pp->state.phase;
 432                 }
 433
 434                 return 0;
 435             }
 436         case PPGETMODE:
 437             {
 438                 int mode;
 439
 440                 if (pp->flags & PP_CLAIMED)
 441                         mode = pp->pdev->port->ieee1284.mode;
 442                 else
 443                         mode = pp->state.mode;
 444
 445                 if (copy_to_user(argp, &mode, sizeof(mode)))
 446                         return -EFAULT;
 447                 return 0;
 448             }
 449         case PPSETPHASE:
 450             {
 451                 int phase;
 452
 453                 if (copy_from_user(&phase, argp, sizeof(phase)))
 454                         return -EFAULT;
 455
 456                 /* FIXME: validate phase */
 457                 pp->state.phase = phase;
 458
 459                 if (pp->flags & PP_CLAIMED)
 460                         pp->pdev->port->ieee1284.phase = phase;
 461
 462                 return 0;
 463             }
 464         case PPGETPHASE:
 465             {
 466                 int phase;
 467
 468                 if (pp->flags & PP_CLAIMED)
 469                         phase = pp->pdev->port->ieee1284.phase;
 470                 else
 471                         phase = pp->state.phase;
 472                 if (copy_to_user(argp, &phase, sizeof(phase)))
 473                         return -EFAULT;
 474                 return 0;
 475             }
 476         case PPGETMODES:
 477             {
 478                 unsigned int modes;
 479
 480                 port = parport_find_number(minor);
 481                 if (!port)
 482                         return -ENODEV;
 483
 484                 modes = port->modes;
 485                 parport_put_port(port);
 486                 if (copy_to_user(argp, &modes, sizeof(modes)))
 487                         return -EFAULT;
 488                 return 0;
 489             }
 490         case PPSETFLAGS:
 491             {
 492                 int uflags;
 493
 494                 if (copy_from_user(&uflags, argp, sizeof(uflags)))
 495                         return -EFAULT;
 496                 pp->flags &= ~PP_FLAGMASK;
 497                 pp->flags |= (uflags & PP_FLAGMASK);
 498                 return 0;
 499             }
 500         case PPGETFLAGS:
 501             {
 502                 int uflags;
 503
 504                 uflags = pp->flags & PP_FLAGMASK;
 505                 if (copy_to_user(argp, &uflags, sizeof(uflags)))
 506                         return -EFAULT;
 507                 return 0;
 508             }
 509         }       /* end switch() */
 510
 511         /* Everything else requires the port to be claimed, so check
 512          * that now. */
 513         if ((pp->flags & PP_CLAIMED) == 0) {
 514                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 515                 return -EINVAL;
 516         }
 517
 518         port = pp->pdev->port;
 519         switch (cmd) {
 520                 struct ieee1284_info *info;
 521                 unsigned char reg;
 522                 unsigned char mask;
 523                 int mode;
 524                 s32 time32[2];
 525                 s64 time64[2];
 526                 struct timespec64 ts;
 527                 int ret;
 528
 529         case PPRSTATUS:
 530                 reg = parport_read_status(port);
 531                 if (copy_to_user(argp, &reg, sizeof(reg)))
 532                         return -EFAULT;
 533                 return 0;
 534         case PPRDATA:
 535                 reg = parport_read_data(port);
 536                 if (copy_to_user(argp, &reg, sizeof(reg)))
 537                         return -EFAULT;
 538                 return 0;
 539         case PPRCONTROL:
 540                 reg = parport_read_control(port);
 541                 if (copy_to_user(argp, &reg, sizeof(reg)))
 542                         return -EFAULT;
 543                 return 0;
 544         case PPYIELD:
 545                 parport_yield_blocking(pp->pdev);
 546                 return 0;
 547
 548         case PPRELEASE:
 549                 /* Save the state machine's state. */
 550                 info = &pp->pdev->port->ieee1284;
 551                 pp->state.mode = info->mode;
 552                 pp->state.phase = info->phase;
 553                 info->mode = pp->saved_state.mode;
 554                 info->phase = pp->saved_state.phase;
 555                 parport_release(pp->pdev);
 556                 pp->flags &= ~PP_CLAIMED;
 557                 return 0;
 558
 559         case PPWCONTROL:
 560                 if (copy_from_user(&reg, argp, sizeof(reg)))
 561                         return -EFAULT;
 562                 parport_write_control(port, reg);
 563                 return 0;
 564
 565         case PPWDATA:
 566                 if (copy_from_user(&reg, argp, sizeof(reg)))
 567                         return -EFAULT;
 568                 parport_write_data(port, reg);
 569                 return 0;
 570
 571         case PPFCONTROL:
 572                 if (copy_from_user(&mask, argp,
 573                                    sizeof(mask)))
 574                         return -EFAULT;
 575                 if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
 576                                    sizeof(reg)))
 577                         return -EFAULT;
 578                 parport_frob_control(port, mask, reg);
 579                 return 0;
 580
 581         case PPDATADIR:
 582                 if (copy_from_user(&mode, argp, sizeof(mode)))
 583                         return -EFAULT;
 584                 if (mode)
 585                         port->ops->data_reverse(port);
 586                 else
 587                         port->ops->data_forward(port);
 588                 return 0;
 589
 590         case PPNEGOT:
 591                 if (copy_from_user(&mode, argp, sizeof(mode)))
 592                         return -EFAULT;
 593                 switch ((ret = parport_negotiate(port, mode))) {
 594                 case 0: break;
 595                 case -1: /* handshake failed, peripheral not IEEE 1284 */
 596                         ret = -EIO;
 597                         break;
 598                 case 1:  /* handshake succeeded, peripheral rejected mode */
 599                         ret = -ENXIO;
 600                         break;
 601                 }
 602                 pp_enable_irq(pp);
 603                 return ret;
 604
 605         case PPWCTLONIRQ:
 606                 if (copy_from_user(&reg, argp, sizeof(reg)))
 607                         return -EFAULT;
 608
 609                 /* Remember what to set the control lines to, for next
 610                  * time we get an interrupt. */
 611                 pp->irqctl = reg;
 612                 pp->irqresponse = 1;
 613                 return 0;
 614
 615         case PPCLRIRQ:
 616                 ret = atomic_read(&pp->irqc);
 617                 if (copy_to_user(argp, &ret, sizeof(ret)))
 618                         return -EFAULT;
 619                 atomic_sub(ret, &pp->irqc);
 620                 return 0;
 621
 622         case PPSETTIME32:
 623                 if (copy_from_user(time32, argp, sizeof(time32)))
 624                         return -EFAULT;
 625
 626                 if ((time32[0] < 0) || (time32[1] < 0))
 627                         return -EINVAL;
 628
 629                 return pp_set_timeout(pp->pdev, time32[0], time32[1]);
 630
 631         case PPSETTIME64:
 632                 if (copy_from_user(time64, argp, sizeof(time64)))
 633                         return -EFAULT;
 634
 635                 if ((time64[0] < 0) || (time64[1] < 0))
 636                         return -EINVAL;
 637
 638                 if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
 639                         time64[1] >>= 32;
 640
 641                 return pp_set_timeout(pp->pdev, time64[0], time64[1]);
 642
 643         case PPGETTIME32:
 644                 jiffies_to_timespec64(pp->pdev->timeout, &ts);
 645                 time32[0] = ts.tv_sec;
 646                 time32[1] = ts.tv_nsec / NSEC_PER_USEC;
 647
 648                 if (copy_to_user(argp, time32, sizeof(time32)))
 649                         return -EFAULT;
 650
 651                 return 0;
 652
 653         case PPGETTIME64:
 654                 jiffies_to_timespec64(pp->pdev->timeout, &ts);
 655                 time64[0] = ts.tv_sec;
 656                 time64[1] = ts.tv_nsec / NSEC_PER_USEC;
 657
 658                 if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
 659                         time64[1] <<= 32;
 660
 661                 if (copy_to_user(argp, time64, sizeof(time64)))
 662                         return -EFAULT;
 663
 664                 return 0;
 665
 666         default:
 667                 dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
 668                 return -EINVAL;
 669         }
 670
 671         /* Keep the compiler happy */
 672         return 0;
 673 }
 674
 675 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 676 {
 677         long ret;
 678
 679         mutex_lock(&pp_do_mutex);
 680         ret = pp_do_ioctl(file, cmd, arg);
 681         mutex_unlock(&pp_do_mutex);
 682         return ret;
 683 }
 684
 685 #ifdef CONFIG_COMPAT
 686 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
 687                             unsigned long arg)
 688 {
 689         return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 690 }
 691 #endif
 692
 693 static int pp_open(struct inode *inode, struct file *file)
 694 {
 695         unsigned int minor = iminor(inode);
 696         struct pp_struct *pp;
 697
 698         if (minor >= PARPORT_MAX)
 699                 return -ENXIO;
 700
 701         pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
 702         if (!pp)
 703                 return -ENOMEM;
 704
 705         pp->state.mode = IEEE1284_MODE_COMPAT;
 706         pp->state.phase = init_phase(pp->state.mode);
 707         pp->flags = 0;
 708         pp->irqresponse = 0;
 709         atomic_set(&pp->irqc, 0);
 710         init_waitqueue_head(&pp->irq_wait);
 711
 712         /* Defer the actual device registration until the first claim.
 713          * That way, we know whether or not the driver wants to have
 714          * exclusive access to the port (PPEXCL).
 715          */
 716         pp->pdev = NULL;
 717         file->private_data = pp;
 718
 719         return 0;
 720 }
 721
 722 static int pp_release(struct inode *inode, struct file *file)
 723 {
 724         unsigned int minor = iminor(inode);
 725         struct pp_struct *pp = file->private_data;
 726         int compat_negot;
 727
 728         compat_negot = 0;
 729         if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
 730             (pp->state.mode != IEEE1284_MODE_COMPAT)) {
 731                 struct ieee1284_info *info;
 732
 733                 /* parport released, but not in compatibility mode */
 734                 parport_claim_or_block(pp->pdev);
 735                 pp->flags |= PP_CLAIMED;
 736                 info = &pp->pdev->port->ieee1284;
 737                 pp->saved_state.mode = info->mode;
 738                 pp->saved_state.phase = info->phase;
 739                 info->mode = pp->state.mode;
 740                 info->phase = pp->state.phase;
 741                 compat_negot = 1;
 742         } else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
 743             (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
 744                 compat_negot = 2;
 745         }
 746         if (compat_negot) {
 747                 parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
 748                 dev_dbg(&pp->pdev->dev,
 749                         "negotiated back to compatibility mode because user-space forgot\n");
 750         }
 751
 752         if (pp->flags & PP_CLAIMED) {
 753                 struct ieee1284_info *info;
 754
 755                 info = &pp->pdev->port->ieee1284;
 756                 pp->state.mode = info->mode;
 757                 pp->state.phase = info->phase;
 758                 info->mode = pp->saved_state.mode;
 759                 info->phase = pp->saved_state.phase;
 760                 parport_release(pp->pdev);
 761                 if (compat_negot != 1) {
 762                         pr_debug(CHRDEV "%x: released pardevice "
 763                                 "because user-space forgot\n", minor);
 764                 }
 765         }
 766
 767         if (pp->pdev) {
 768                 parport_unregister_device(pp->pdev);
 769                 ida_simple_remove(&ida_index, pp->index);
 770                 pp->pdev = NULL;
 771                 pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
 772         }
 773
 774         kfree(pp);
 775
 776         return 0;
 777 }
 778
 779 /* No kernel lock held - fine */
 780 static __poll_t pp_poll(struct file *file, poll_table *wait)
 781 {
 782         struct pp_struct *pp = file->private_data;
 783         __poll_t mask = 0;
 784
 785         poll_wait(file, &pp->irq_wait, wait);
 786         if (atomic_read(&pp->irqc))
 787                 mask |= EPOLLIN | EPOLLRDNORM;
 788
 789         return mask;
 790 }
 791
 792 static struct class *ppdev_class;
 793
 794 static const struct file_operations pp_fops = {
 795         .owner          = THIS_MODULE,
 796         .llseek         = no_llseek,
 797         .read           = pp_read,
 798         .write          = pp_write,
 799         .poll           = pp_poll,
 800         .unlocked_ioctl = pp_ioctl,
 801 #ifdef CONFIG_COMPAT
 802         .compat_ioctl   = pp_compat_ioctl,
 803 #endif
 804         .open           = pp_open,
 805         .release        = pp_release,
 806 };
 807
 808 static void pp_attach(struct parport *port)
 809 {
 810         struct device *ret;
 811
 812         if (devices[port->number])
 813                 return;
 814
 815         ret = device_create(ppdev_class, port->dev,
 816                             MKDEV(PP_MAJOR, port->number), NULL,
 817                             "parport%d", port->number);
 818         if (IS_ERR(ret)) {
 819                 pr_err("Failed to create device parport%d\n",
 820                        port->number);
 821                 return;
 822         }
 823         devices[port->number] = ret;
 824 }
 825
 826 static void pp_detach(struct parport *port)
 827 {
 828         if (!devices[port->number])
 829                 return;
 830
 831         device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
 832         devices[port->number] = NULL;
 833 }
 834
 835 static int pp_probe(struct pardevice *par_dev)
 836 {
 837         struct device_driver *drv = par_dev->dev.driver;
 838         int len = strlen(drv->name);
 839
 840         if (strncmp(par_dev->name, drv->name, len))
 841                 return -ENODEV;
 842
 843         return 0;
 844 }
 845
 846 static struct parport_driver pp_driver = {
 847         .name           = CHRDEV,
 848         .probe          = pp_probe,
 849         .match_port     = pp_attach,
 850         .detach         = pp_detach,
 851         .devmodel       = true,
 852 };
 853
 854 static int __init ppdev_init(void)
 855 {
 856         int err = 0;
 857
 858         if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
 859                 pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
 860                 return -EIO;
 861         }
 862         ppdev_class = class_create(THIS_MODULE, CHRDEV);
 863         if (IS_ERR(ppdev_class)) {
 864                 err = PTR_ERR(ppdev_class);
 865                 goto out_chrdev;
 866         }
 867         err = parport_register_driver(&pp_driver);
 868         if (err < 0) {
 869                 pr_warn(CHRDEV ": unable to register with parport\n");
 870                 goto out_class;
 871         }
 872
 873         pr_info(PP_VERSION "\n");
 874         goto out;
 875
 876 out_class:
 877         class_destroy(ppdev_class);
 878 out_chrdev:
 879         unregister_chrdev(PP_MAJOR, CHRDEV);
 880 out:
 881         return err;
 882 }
 883
 884 static void __exit ppdev_cleanup(void)
 885 {
 886         /* Clean up all parport stuff */
 887         parport_unregister_driver(&pp_driver);
 888         class_destroy(ppdev_class);
 889         unregister_chrdev(PP_MAJOR, CHRDEV);
 890 }
 891
 892 module_init(ppdev_init);
 893 module_exit(ppdev_cleanup);
 894
 895 MODULE_LICENSE("GPL");
 896 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);