drivers/char/ppdev.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * linux/drivers/char/ppdev.c
   4  *
   5  * This is the code behind /dev/parport* -- it allows a user-space
   6  * application to use the parport subsystem.
   7  *
   8  * Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
   9  *
  10  * A /dev/parportx device node represents an arbitrary device
  11  * on port 'x'.  The following operations are possible:
  12  *
  13  * open         do nothing, set up default IEEE 1284 protocol to be COMPAT
  14  * close        release port and unregister device (if necessary)
  15  * ioctl
  16  *   EXCL       register device exclusively (may fail)
  17  *   CLAIM      (register device first time) parport_claim_or_block
  18  *   RELEASE    parport_release
  19  *   SETMODE    set the IEEE 1284 protocol to use for read/write
  20  *   SETPHASE   set the IEEE 1284 phase of a particular mode.  Not to be
  21  *              confused with ioctl(fd, SETPHASER, &stun). ;-)
  22  *   DATADIR    data_forward / data_reverse
  23  *   WDATA      write_data
  24  *   RDATA      read_data
  25  *   WCONTROL   write_control
  26  *   RCONTROL   read_control
  27  *   FCONTROL   frob_control
  28  *   RSTATUS    read_status
  29  *   NEGOT      parport_negotiate
  30  *   YIELD      parport_yield_blocking
  31  *   WCTLONIRQ  on interrupt, set control lines
  32  *   CLRIRQ     clear (and return) interrupt count
  33  *   SETTIME    sets device timeout (struct timeval)
  34  *   GETTIME    gets device timeout (struct timeval)
  35  *   GETMODES   gets hardware supported modes (unsigned int)
  36  *   GETMODE    gets the current IEEE1284 mode
  37  *   GETPHASE   gets the current IEEE1284 phase
  38  *   GETFLAGS   gets current (user-visible) flags
  39  *   SETFLAGS   sets current (user-visible) flags
  40  * read/write   read or write in current IEEE 1284 protocol
  41  * select       wait for interrupt (in readfds)
  42  *
  43  * Changes:
  44  * Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
  45  *
  46  * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
  47  * - On error, copy_from_user and copy_to_user do not return -EFAULT,
  48  *   They return the positive number of bytes *not* copied due to address
  49  *   space errors.
  50  *
  51  * Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
  52  * Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
  53  */
  54
  55 #include <linux/module.h>
  56 #include <linux/init.h>
  57 #include <linux/sched/signal.h>
  58 #include <linux/device.h>
  59 #include <linux/ioctl.h>
  60 #include <linux/parport.h>
  61 #include <linux/ctype.h>
  62 #include <linux/poll.h>
  63 #include <linux/slab.h>
  64 #include <linux/major.h>
  65 #include <linux/ppdev.h>
  66 #include <linux/mutex.h>
  67 #include <linux/uaccess.h>
  68 #include <linux/compat.h>
  69
  70 #define PP_VERSION "ppdev: user-space parallel port driver"
  71 #define CHRDEV "ppdev"
  72
  73 struct pp_struct {
  74         struct pardevice *pdev;
  75         wait_queue_head_t irq_wait;
  76         atomic_t irqc;
  77         unsigned int flags;
  78         int irqresponse;
  79         unsigned char irqctl;
  80         struct ieee1284_info state;
  81         struct ieee1284_info saved_state;
  82         long default_inactivity;
  83         int index;
  84 };
  85
  86 /* should we use PARDEVICE_MAX here? */
  87 static struct device *devices[PARPORT_MAX];
  88
  89 static DEFINE_IDA(ida_index);
  90
  91 /* pp_struct.flags bitfields */
  92 #define PP_CLAIMED    (1<<0)
  93 #define PP_EXCL       (1<<1)
  94
  95 /* Other constants */
  96 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
  97 #define PP_BUFFER_SIZE 1024
  98 #define PARDEVICE_MAX 8
  99
 100 static DEFINE_MUTEX(pp_do_mutex);
 101
 102 /* define fixed sized ioctl cmd for y2038 migration */
 103 #define PPGETTIME32     _IOR(PP_IOCTL, 0x95, s32[2])
 104 #define PPSETTIME32     _IOW(PP_IOCTL, 0x96, s32[2])
 105 #define PPGETTIME64     _IOR(PP_IOCTL, 0x95, s64[2])
 106 #define PPSETTIME64     _IOW(PP_IOCTL, 0x96, s64[2])
 107
 108 static inline void pp_enable_irq(struct pp_struct *pp)
 109 {
 110         struct parport *port = pp->pdev->port;
 111
 112         port->ops->enable_irq(port);
 113 }
 114
 115 static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
 116                        loff_t *ppos)
 117 {
 118         unsigned int minor = iminor(file_inode(file));
 119         struct pp_struct *pp = file->private_data;
 120         char *kbuffer;
 121         ssize_t bytes_read = 0;
 122         struct parport *pport;
 123         int mode;
 124
 125         if (!(pp->flags & PP_CLAIMED)) {
 126                 /* Don't have the port claimed */
 127                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 128                 return -EINVAL;
 129         }
 130
 131         /* Trivial case. */
 132         if (count == 0)
 133                 return 0;
 134
 135         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 136         if (!kbuffer)
 137                 return -ENOMEM;
 138         pport = pp->pdev->port;
 139         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 140
 141         parport_set_timeout(pp->pdev,
 142                             (file->f_flags & O_NONBLOCK) ?
 143                             PARPORT_INACTIVITY_O_NONBLOCK :
 144                             pp->default_inactivity);
 145
 146         while (bytes_read == 0) {
 147                 ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
 148
 149                 if (mode == IEEE1284_MODE_EPP) {
 150                         /* various specials for EPP mode */
 151                         int flags = 0;
 152                         size_t (*fn)(struct parport *, void *, size_t, int);
 153
 154                         if (pp->flags & PP_W91284PIC)
 155                                 flags |= PARPORT_W91284PIC;
 156                         if (pp->flags & PP_FASTREAD)
 157                                 flags |= PARPORT_EPP_FAST;
 158                         if (pport->ieee1284.mode & IEEE1284_ADDR)
 159                                 fn = pport->ops->epp_read_addr;
 160                         else
 161                                 fn = pport->ops->epp_read_data;
 162                         bytes_read = (*fn)(pport, kbuffer, need, flags);
 163                 } else {
 164                         bytes_read = parport_read(pport, kbuffer, need);
 165                 }
 166
 167                 if (bytes_read != 0)
 168                         break;
 169
 170                 if (file->f_flags & O_NONBLOCK) {
 171                         bytes_read = -EAGAIN;
 172                         break;
 173                 }
 174
 175                 if (signal_pending(current)) {
 176                         bytes_read = -ERESTARTSYS;
 177                         break;
 178                 }
 179
 180                 cond_resched();
 181         }
 182
 183         parport_set_timeout(pp->pdev, pp->default_inactivity);
 184
 185         if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
 186                 bytes_read = -EFAULT;
 187
 188         kfree(kbuffer);
 189         pp_enable_irq(pp);
 190         return bytes_read;
 191 }
 192
 193 static ssize_t pp_write(struct file *file, const char __user *buf,
 194                         size_t count, loff_t *ppos)
 195 {
 196         unsigned int minor = iminor(file_inode(file));
 197         struct pp_struct *pp = file->private_data;
 198         char *kbuffer;
 199         ssize_t bytes_written = 0;
 200         ssize_t wrote;
 201         int mode;
 202         struct parport *pport;
 203
 204         if (!(pp->flags & PP_CLAIMED)) {
 205                 /* Don't have the port claimed */
 206                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 207                 return -EINVAL;
 208         }
 209
 210         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 211         if (!kbuffer)
 212                 return -ENOMEM;
 213
 214         pport = pp->pdev->port;
 215         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 216
 217         parport_set_timeout(pp->pdev,
 218                             (file->f_flags & O_NONBLOCK) ?
 219                             PARPORT_INACTIVITY_O_NONBLOCK :
 220                             pp->default_inactivity);
 221
 222         while (bytes_written < count) {
 223                 ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
 224
 225                 if (copy_from_user(kbuffer, buf + bytes_written, n)) {
 226                         bytes_written = -EFAULT;
 227                         break;
 228                 }
 229
 230                 if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
 231                         /* do a fast EPP write */
 232                         if (pport->ieee1284.mode & IEEE1284_ADDR) {
 233                                 wrote = pport->ops->epp_write_addr(pport,
 234                                         kbuffer, n, PARPORT_EPP_FAST);
 235                         } else {
 236                                 wrote = pport->ops->epp_write_data(pport,
 237                                         kbuffer, n, PARPORT_EPP_FAST);
 238                         }
 239                 } else {
 240                         wrote = parport_write(pp->pdev->port, kbuffer, n);
 241                 }
 242
 243                 if (wrote <= 0) {
 244                         if (!bytes_written)
 245                                 bytes_written = wrote;
 246                         break;
 247                 }
 248
 249                 bytes_written += wrote;
 250
 251                 if (file->f_flags & O_NONBLOCK) {
 252                         if (!bytes_written)
 253                                 bytes_written = -EAGAIN;
 254                         break;
 255                 }
 256
 257                 if (signal_pending(current))
 258                         break;
 259
 260                 cond_resched();
 261         }
 262
 263         parport_set_timeout(pp->pdev, pp->default_inactivity);
 264
 265         kfree(kbuffer);
 266         pp_enable_irq(pp);
 267         return bytes_written;
 268 }
 269
 270 static void pp_irq(void *private)
 271 {
 272         struct pp_struct *pp = private;
 273
 274         if (pp->irqresponse) {
 275                 parport_write_control(pp->pdev->port, pp->irqctl);
 276                 pp->irqresponse = 0;
 277         }
 278
 279         atomic_inc(&pp->irqc);
 280         wake_up_interruptible(&pp->irq_wait);
 281 }
 282
 283 static int register_device(int minor, struct pp_struct *pp)
 284 {
 285         struct parport *port;
 286         struct pardevice *pdev = NULL;
 287         char *name;
 288         struct pardev_cb ppdev_cb;
 289         int rc = 0, index;
 290
 291         name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
 292         if (name == NULL)
 293                 return -ENOMEM;
 294
 295         port = parport_find_number(minor);
 296         if (!port) {
 297                 pr_warn("%s: no associated port!\n", name);
 298                 rc = -ENXIO;
 299                 goto err;
 300         }
 301
 302         index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
 303         memset(&ppdev_cb, 0, sizeof(ppdev_cb));
 304         ppdev_cb.irq_func = pp_irq;
 305         ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
 306         ppdev_cb.private = pp;
 307         pdev = parport_register_dev_model(port, name, &ppdev_cb, index);
 308         parport_put_port(port);
 309
 310         if (!pdev) {
 311                 pr_warn("%s: failed to register device!\n", name);
 312                 rc = -ENXIO;
 313                 ida_simple_remove(&ida_index, index);
 314                 goto err;
 315         }
 316
 317         pp->pdev = pdev;
 318         pp->index = index;
 319         dev_dbg(&pdev->dev, "registered pardevice\n");
 320 err:
 321         kfree(name);
 322         return rc;
 323 }
 324
 325 static enum ieee1284_phase init_phase(int mode)
 326 {
 327         switch (mode & ~(IEEE1284_DEVICEID
 328                          | IEEE1284_ADDR)) {
 329         case IEEE1284_MODE_NIBBLE:
 330         case IEEE1284_MODE_BYTE:
 331                 return IEEE1284_PH_REV_IDLE;
 332         }
 333         return IEEE1284_PH_FWD_IDLE;
 334 }
 335
 336 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
 337 {
 338         long to_jiffies;
 339
 340         if ((tv_sec < 0) || (tv_usec < 0))
 341                 return -EINVAL;
 342
 343         to_jiffies = usecs_to_jiffies(tv_usec);
 344         to_jiffies += tv_sec * HZ;
 345         if (to_jiffies <= 0)
 346                 return -EINVAL;
 347
 348         pdev->timeout = to_jiffies;
 349         return 0;
 350 }
 351
 352 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 353 {
 354         unsigned int minor = iminor(file_inode(file));
 355         struct pp_struct *pp = file->private_data;
 356         struct parport *port;
 357         void __user *argp = (void __user *)arg;
 358
 359         /* First handle the cases that don't take arguments. */
 360         switch (cmd) {
 361         case PPCLAIM:
 362             {
 363                 struct ieee1284_info *info;
 364                 int ret;
 365
 366                 if (pp->flags & PP_CLAIMED) {
 367                         dev_dbg(&pp->pdev->dev, "you've already got it!\n");
 368                         return -EINVAL;
 369                 }
 370
 371                 /* Deferred device registration. */
 372                 if (!pp->pdev) {
 373                         int err = register_device(minor, pp);
 374
 375                         if (err)
 376                                 return err;
 377                 }
 378
 379                 ret = parport_claim_or_block(pp->pdev);
 380                 if (ret < 0)
 381                         return ret;
 382
 383                 pp->flags |= PP_CLAIMED;
 384
 385                 /* For interrupt-reporting to work, we need to be
 386                  * informed of each interrupt. */
 387                 pp_enable_irq(pp);
 388
 389                 /* We may need to fix up the state machine. */
 390                 info = &pp->pdev->port->ieee1284;
 391                 pp->saved_state.mode = info->mode;
 392                 pp->saved_state.phase = info->phase;
 393                 info->mode = pp->state.mode;
 394                 info->phase = pp->state.phase;
 395                 pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
 396                 parport_set_timeout(pp->pdev, pp->default_inactivity);
 397
 398                 return 0;
 399             }
 400         case PPEXCL:
 401                 if (pp->pdev) {
 402                         dev_dbg(&pp->pdev->dev,
 403                                 "too late for PPEXCL; already registered\n");
 404                         if (pp->flags & PP_EXCL)
 405                                 /* But it's not really an error. */
 406                                 return 0;
 407                         /* There's no chance of making the driver happy. */
 408                         return -EINVAL;
 409                 }
 410
 411                 /* Just remember to register the device exclusively
 412                  * when we finally do the registration. */
 413                 pp->flags |= PP_EXCL;
 414                 return 0;
 415         case PPSETMODE:
 416             {
 417                 int mode;
 418
 419                 if (copy_from_user(&mode, argp, sizeof(mode)))
 420                         return -EFAULT;
 421                 /* FIXME: validate mode */
 422                 pp->state.mode = mode;
 423                 pp->state.phase = init_phase(mode);
 424
 425                 if (pp->flags & PP_CLAIMED) {
 426                         pp->pdev->port->ieee1284.mode = mode;
 427                         pp->pdev->port->ieee1284.phase = pp->state.phase;
 428                 }
 429
 430                 return 0;
 431             }
 432         case PPGETMODE:
 433             {
 434                 int mode;
 435
 436                 if (pp->flags & PP_CLAIMED)
 437                         mode = pp->pdev->port->ieee1284.mode;
 438                 else
 439                         mode = pp->state.mode;
 440
 441                 if (copy_to_user(argp, &mode, sizeof(mode)))
 442                         return -EFAULT;
 443                 return 0;
 444             }
 445         case PPSETPHASE:
 446             {
 447                 int phase;
 448
 449                 if (copy_from_user(&phase, argp, sizeof(phase)))
 450                         return -EFAULT;
 451
 452                 /* FIXME: validate phase */
 453                 pp->state.phase = phase;
 454
 455                 if (pp->flags & PP_CLAIMED)
 456                         pp->pdev->port->ieee1284.phase = phase;
 457
 458                 return 0;
 459             }
 460         case PPGETPHASE:
 461             {
 462                 int phase;
 463
 464                 if (pp->flags & PP_CLAIMED)
 465                         phase = pp->pdev->port->ieee1284.phase;
 466                 else
 467                         phase = pp->state.phase;
 468                 if (copy_to_user(argp, &phase, sizeof(phase)))
 469                         return -EFAULT;
 470                 return 0;
 471             }
 472         case PPGETMODES:
 473             {
 474                 unsigned int modes;
 475
 476                 port = parport_find_number(minor);
 477                 if (!port)
 478                         return -ENODEV;
 479
 480                 modes = port->modes;
 481                 parport_put_port(port);
 482                 if (copy_to_user(argp, &modes, sizeof(modes)))
 483                         return -EFAULT;
 484                 return 0;
 485             }
 486         case PPSETFLAGS:
 487             {
 488                 int uflags;
 489
 490                 if (copy_from_user(&uflags, argp, sizeof(uflags)))
 491                         return -EFAULT;
 492                 pp->flags &= ~PP_FLAGMASK;
 493                 pp->flags |= (uflags & PP_FLAGMASK);
 494                 return 0;
 495             }
 496         case PPGETFLAGS:
 497             {
 498                 int uflags;
 499
 500                 uflags = pp->flags & PP_FLAGMASK;
 501                 if (copy_to_user(argp, &uflags, sizeof(uflags)))
 502                         return -EFAULT;
 503                 return 0;
 504             }
 505         }       /* end switch() */
 506
 507         /* Everything else requires the port to be claimed, so check
 508          * that now. */
 509         if ((pp->flags & PP_CLAIMED) == 0) {
 510                 pr_debug(CHRDEV "%x: claim the port first\n", minor);
 511                 return -EINVAL;
 512         }
 513
 514         port = pp->pdev->port;
 515         switch (cmd) {
 516                 struct ieee1284_info *info;
 517                 unsigned char reg;
 518                 unsigned char mask;
 519                 int mode;
 520                 s32 time32[2];
 521                 s64 time64[2];
 522                 struct timespec64 ts;
 523                 int ret;
 524
 525         case PPRSTATUS:
 526                 reg = parport_read_status(port);
 527                 if (copy_to_user(argp, &reg, sizeof(reg)))
 528                         return -EFAULT;
 529                 return 0;
 530         case PPRDATA:
 531                 reg = parport_read_data(port);
 532                 if (copy_to_user(argp, &reg, sizeof(reg)))
 533                         return -EFAULT;
 534                 return 0;
 535         case PPRCONTROL:
 536                 reg = parport_read_control(port);
 537                 if (copy_to_user(argp, &reg, sizeof(reg)))
 538                         return -EFAULT;
 539                 return 0;
 540         case PPYIELD:
 541                 parport_yield_blocking(pp->pdev);
 542                 return 0;
 543
 544         case PPRELEASE:
 545                 /* Save the state machine's state. */
 546                 info = &pp->pdev->port->ieee1284;
 547                 pp->state.mode = info->mode;
 548                 pp->state.phase = info->phase;
 549                 info->mode = pp->saved_state.mode;
 550                 info->phase = pp->saved_state.phase;
 551                 parport_release(pp->pdev);
 552                 pp->flags &= ~PP_CLAIMED;
 553                 return 0;
 554
 555         case PPWCONTROL:
 556                 if (copy_from_user(&reg, argp, sizeof(reg)))
 557                         return -EFAULT;
 558                 parport_write_control(port, reg);
 559                 return 0;
 560
 561         case PPWDATA:
 562                 if (copy_from_user(&reg, argp, sizeof(reg)))
 563                         return -EFAULT;
 564                 parport_write_data(port, reg);
 565                 return 0;
 566
 567         case PPFCONTROL:
 568                 if (copy_from_user(&mask, argp,
 569                                    sizeof(mask)))
 570                         return -EFAULT;
 571                 if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
 572                                    sizeof(reg)))
 573                         return -EFAULT;
 574                 parport_frob_control(port, mask, reg);
 575                 return 0;
 576
 577         case PPDATADIR:
 578                 if (copy_from_user(&mode, argp, sizeof(mode)))
 579                         return -EFAULT;
 580                 if (mode)
 581                         port->ops->data_reverse(port);
 582                 else
 583                         port->ops->data_forward(port);
 584                 return 0;
 585
 586         case PPNEGOT:
 587                 if (copy_from_user(&mode, argp, sizeof(mode)))
 588                         return -EFAULT;
 589                 switch ((ret = parport_negotiate(port, mode))) {
 590                 case 0: break;
 591                 case -1: /* handshake failed, peripheral not IEEE 1284 */
 592                         ret = -EIO;
 593                         break;
 594                 case 1:  /* handshake succeeded, peripheral rejected mode */
 595                         ret = -ENXIO;
 596                         break;
 597                 }
 598                 pp_enable_irq(pp);
 599                 return ret;
 600
 601         case PPWCTLONIRQ:
 602                 if (copy_from_user(&reg, argp, sizeof(reg)))
 603                         return -EFAULT;
 604
 605                 /* Remember what to set the control lines to, for next
 606                  * time we get an interrupt. */
 607                 pp->irqctl = reg;
 608                 pp->irqresponse = 1;
 609                 return 0;
 610
 611         case PPCLRIRQ:
 612                 ret = atomic_read(&pp->irqc);
 613                 if (copy_to_user(argp, &ret, sizeof(ret)))
 614                         return -EFAULT;
 615                 atomic_sub(ret, &pp->irqc);
 616                 return 0;
 617
 618         case PPSETTIME32:
 619                 if (copy_from_user(time32, argp, sizeof(time32)))
 620                         return -EFAULT;
 621
 622                 return pp_set_timeout(pp->pdev, time32[0], time32[1]);
 623
 624         case PPSETTIME64:
 625                 if (copy_from_user(time64, argp, sizeof(time64)))
 626                         return -EFAULT;
 627
 628                 return pp_set_timeout(pp->pdev, time64[0], time64[1]);
 629
 630         case PPGETTIME32:
 631                 jiffies_to_timespec64(pp->pdev->timeout, &ts);
 632                 time32[0] = ts.tv_sec;
 633                 time32[1] = ts.tv_nsec / NSEC_PER_USEC;
 634                 if ((time32[0] < 0) || (time32[1] < 0))
 635                         return -EINVAL;
 636
 637                 if (copy_to_user(argp, time32, sizeof(time32)))
 638                         return -EFAULT;
 639
 640                 return 0;
 641
 642         case PPGETTIME64:
 643                 jiffies_to_timespec64(pp->pdev->timeout, &ts);
 644                 time64[0] = ts.tv_sec;
 645                 time64[1] = ts.tv_nsec / NSEC_PER_USEC;
 646                 if ((time64[0] < 0) || (time64[1] < 0))
 647                         return -EINVAL;
 648
 649                 if (copy_to_user(argp, time64, sizeof(time64)))
 650                         return -EFAULT;
 651
 652                 return 0;
 653
 654         default:
 655                 dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
 656                 return -EINVAL;
 657         }
 658
 659         /* Keep the compiler happy */
 660         return 0;
 661 }
 662
 663 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 664 {
 665         long ret;
 666
 667         mutex_lock(&pp_do_mutex);
 668         ret = pp_do_ioctl(file, cmd, arg);
 669         mutex_unlock(&pp_do_mutex);
 670         return ret;
 671 }
 672
 673 #ifdef CONFIG_COMPAT
 674 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
 675                             unsigned long arg)
 676 {
 677         return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 678 }
 679 #endif
 680
 681 static int pp_open(struct inode *inode, struct file *file)
 682 {
 683         unsigned int minor = iminor(inode);
 684         struct pp_struct *pp;
 685
 686         if (minor >= PARPORT_MAX)
 687                 return -ENXIO;
 688
 689         pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
 690         if (!pp)
 691                 return -ENOMEM;
 692
 693         pp->state.mode = IEEE1284_MODE_COMPAT;
 694         pp->state.phase = init_phase(pp->state.mode);
 695         pp->flags = 0;
 696         pp->irqresponse = 0;
 697         atomic_set(&pp->irqc, 0);
 698         init_waitqueue_head(&pp->irq_wait);
 699
 700         /* Defer the actual device registration until the first claim.
 701          * That way, we know whether or not the driver wants to have
 702          * exclusive access to the port (PPEXCL).
 703          */
 704         pp->pdev = NULL;
 705         file->private_data = pp;
 706
 707         return 0;
 708 }
 709
 710 static int pp_release(struct inode *inode, struct file *file)
 711 {
 712         unsigned int minor = iminor(inode);
 713         struct pp_struct *pp = file->private_data;
 714         int compat_negot;
 715
 716         compat_negot = 0;
 717         if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
 718             (pp->state.mode != IEEE1284_MODE_COMPAT)) {
 719                 struct ieee1284_info *info;
 720
 721                 /* parport released, but not in compatibility mode */
 722                 parport_claim_or_block(pp->pdev);
 723                 pp->flags |= PP_CLAIMED;
 724                 info = &pp->pdev->port->ieee1284;
 725                 pp->saved_state.mode = info->mode;
 726                 pp->saved_state.phase = info->phase;
 727                 info->mode = pp->state.mode;
 728                 info->phase = pp->state.phase;
 729                 compat_negot = 1;
 730         } else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
 731             (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
 732                 compat_negot = 2;
 733         }
 734         if (compat_negot) {
 735                 parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
 736                 dev_dbg(&pp->pdev->dev,
 737                         "negotiated back to compatibility mode because user-space forgot\n");
 738         }
 739
 740         if ((pp->flags & PP_CLAIMED) && pp->pdev) {
 741                 struct ieee1284_info *info;
 742
 743                 info = &pp->pdev->port->ieee1284;
 744                 pp->state.mode = info->mode;
 745                 pp->state.phase = info->phase;
 746                 info->mode = pp->saved_state.mode;
 747                 info->phase = pp->saved_state.phase;
 748                 parport_release(pp->pdev);
 749                 if (compat_negot != 1) {
 750                         pr_debug(CHRDEV "%x: released pardevice "
 751                                 "because user-space forgot\n", minor);
 752                 }
 753         }
 754
 755         if (pp->pdev) {
 756                 parport_unregister_device(pp->pdev);
 757                 ida_simple_remove(&ida_index, pp->index);
 758                 pp->pdev = NULL;
 759                 pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
 760         }
 761
 762         kfree(pp);
 763
 764         return 0;
 765 }
 766
 767 /* No kernel lock held - fine */
 768 static __poll_t pp_poll(struct file *file, poll_table *wait)
 769 {
 770         struct pp_struct *pp = file->private_data;
 771         __poll_t mask = 0;
 772
 773         poll_wait(file, &pp->irq_wait, wait);
 774         if (atomic_read(&pp->irqc))
 775                 mask |= EPOLLIN | EPOLLRDNORM;
 776
 777         return mask;
 778 }
 779
 780 static struct class *ppdev_class;
 781
 782 static const struct file_operations pp_fops = {
 783         .owner          = THIS_MODULE,
 784         .llseek         = no_llseek,
 785         .read           = pp_read,
 786         .write          = pp_write,
 787         .poll           = pp_poll,
 788         .unlocked_ioctl = pp_ioctl,
 789 #ifdef CONFIG_COMPAT
 790         .compat_ioctl   = pp_compat_ioctl,
 791 #endif
 792         .open           = pp_open,
 793         .release        = pp_release,
 794 };
 795
 796 static void pp_attach(struct parport *port)
 797 {
 798         struct device *ret;
 799
 800         if (devices[port->number])
 801                 return;
 802
 803         ret = device_create(ppdev_class, port->dev,
 804                             MKDEV(PP_MAJOR, port->number), NULL,
 805                             "parport%d", port->number);
 806         if (IS_ERR(ret)) {
 807                 pr_err("Failed to create device parport%d\n",
 808                        port->number);
 809                 return;
 810         }
 811         devices[port->number] = ret;
 812 }
 813
 814 static void pp_detach(struct parport *port)
 815 {
 816         if (!devices[port->number])
 817                 return;
 818
 819         device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
 820         devices[port->number] = NULL;
 821 }
 822
 823 static int pp_probe(struct pardevice *par_dev)
 824 {
 825         struct device_driver *drv = par_dev->dev.driver;
 826         int len = strlen(drv->name);
 827
 828         if (strncmp(par_dev->name, drv->name, len))
 829                 return -ENODEV;
 830
 831         return 0;
 832 }
 833
 834 static struct parport_driver pp_driver = {
 835         .name           = CHRDEV,
 836         .probe          = pp_probe,
 837         .match_port     = pp_attach,
 838         .detach         = pp_detach,
 839         .devmodel       = true,
 840 };
 841
 842 static int __init ppdev_init(void)
 843 {
 844         int err = 0;
 845
 846         if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
 847                 pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
 848                 return -EIO;
 849         }
 850         ppdev_class = class_create(THIS_MODULE, CHRDEV);
 851         if (IS_ERR(ppdev_class)) {
 852                 err = PTR_ERR(ppdev_class);
 853                 goto out_chrdev;
 854         }
 855         err = parport_register_driver(&pp_driver);
 856         if (err < 0) {
 857                 pr_warn(CHRDEV ": unable to register with parport\n");
 858                 goto out_class;
 859         }
 860
 861         pr_info(PP_VERSION "\n");
 862         goto out;
 863
 864 out_class:
 865         class_destroy(ppdev_class);
 866 out_chrdev:
 867         unregister_chrdev(PP_MAJOR, CHRDEV);
 868 out:
 869         return err;
 870 }
 871
 872 static void __exit ppdev_cleanup(void)
 873 {
 874         /* Clean up all parport stuff */
 875         parport_unregister_driver(&pp_driver);
 876         class_destroy(ppdev_class);
 877         unregister_chrdev(PP_MAJOR, CHRDEV);
 878 }
 879
 880 module_init(ppdev_init);
 881 module_exit(ppdev_cleanup);
 882
 883 MODULE_LICENSE("GPL");
 884 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);