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 Tim Waugh <tim@cyberelk.demon.co.uk>
   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  * read/write   read or write in current IEEE 1284 protocol
  40  * select       wait for interrupt (in readfds)
  41  *
  42  * Added SETTIME/GETTIME ioctl, Fred Barnes 1999.
  43  */
  44
  45 #include <linux/module.h>
  46 #include <linux/init.h>
  47 #include <linux/sched.h>
  48 #include <linux/devfs_fs_kernel.h>
  49 #include <linux/ioctl.h>
  50 #include <linux/parport.h>
  51 #include <linux/ctype.h>
  52 #include <linux/poll.h>
  53 #include <asm/uaccess.h>
  54 #include <linux/ppdev.h>
  55
  56 #define PP_VERSION "ppdev: user-space parallel port driver"
  57 #define CHRDEV "ppdev"
  58
  59 #ifndef min
  60 #define min(a,b) ((a) < (b) ? (a) : (b))
  61 #endif
  62
  63 struct pp_struct {
  64         struct pardevice * pdev;
  65         wait_queue_head_t irq_wait;
  66         atomic_t irqc;
  67         unsigned int flags;
  68         int irqresponse;
  69         unsigned char irqctl;
  70         struct ieee1284_info state;
  71         struct ieee1284_info saved_state;
  72 };
  73
  74 /* pp_struct.flags bitfields */
  75 #define PP_CLAIMED    (1<<0)
  76 #define PP_EXCL       (1<<1)
  77
  78 /* Other constants */
  79 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
  80 #define PP_BUFFER_SIZE 256
  81 #define PARDEVICE_MAX 8
  82
  83 /* ROUND_UP macro from fs/select.c */
  84 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
  85
  86 static inline void pp_enable_irq (struct pp_struct *pp)
  87 {
  88         struct parport *port = pp->pdev->port;
  89         port->ops->enable_irq (port);
  90 }
  91
  92 static loff_t pp_lseek (struct file * file, long long offset, int origin)
  93 {
  94         return -ESPIPE;
  95 }
  96
  97 static ssize_t pp_read (struct file * file, char * buf, size_t count,
  98                         loff_t * ppos)
  99 {
 100         unsigned int minor = MINOR (file->f_dentry->d_inode->i_rdev);
 101         struct pp_struct *pp = file->private_data;
 102         char * kbuffer;
 103         ssize_t bytes_read = 0;
 104         ssize_t got = 0;
 105
 106         if (!(pp->flags & PP_CLAIMED)) {
 107                 /* Don't have the port claimed */
 108                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 109                         minor);
 110                 return -EINVAL;
 111         }
 112
 113         kbuffer = kmalloc (min (count, PP_BUFFER_SIZE), GFP_KERNEL);
 114         if (!kbuffer)
 115                 return -ENOMEM;
 116
 117         while (bytes_read < count) {
 118                 ssize_t need = min(count - bytes_read, PP_BUFFER_SIZE);
 119
 120                 got = parport_read (pp->pdev->port, kbuffer, need);
 121
 122                 if (got <= 0) {
 123                         if (!bytes_read)
 124                                 bytes_read = got;
 125
 126                         break;
 127                 }
 128
 129                 if (copy_to_user (buf + bytes_read, kbuffer, got)) {
 130                         bytes_read = -EFAULT;
 131                         break;
 132                 }
 133
 134                 bytes_read += got;
 135
 136                 if (signal_pending (current)) {
 137                         if (!bytes_read)
 138                                 bytes_read = -EINTR;
 139                         break;
 140                 }
 141
 142                 if (current->need_resched)
 143                         schedule ();
 144         }
 145
 146         kfree (kbuffer);
 147         pp_enable_irq (pp);
 148         return bytes_read;
 149 }
 150
 151 static ssize_t pp_write (struct file * file, const char * buf, size_t count,
 152                          loff_t * ppos)
 153 {
 154         unsigned int minor = MINOR (file->f_dentry->d_inode->i_rdev);
 155         struct pp_struct *pp = file->private_data;
 156         char * kbuffer;
 157         ssize_t bytes_written = 0;
 158         ssize_t wrote;
 159
 160         if (!(pp->flags & PP_CLAIMED)) {
 161                 /* Don't have the port claimed */
 162                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 163                         minor);
 164                 return -EINVAL;
 165         }
 166
 167         kbuffer = kmalloc (min (count, PP_BUFFER_SIZE), GFP_KERNEL);
 168         if (!kbuffer)
 169                 return -ENOMEM;
 170
 171         while (bytes_written < count) {
 172                 ssize_t n = min(count - bytes_written, PP_BUFFER_SIZE);
 173
 174                 if (copy_from_user (kbuffer, buf + bytes_written, n)) {
 175                         bytes_written = -EFAULT;
 176                         break;
 177                 }
 178
 179                 wrote = parport_write (pp->pdev->port, kbuffer, n);
 180
 181                 if (wrote < 0) {
 182                         if (!bytes_written)
 183                                 bytes_written = wrote;
 184                         break;
 185                 }
 186
 187                 bytes_written += wrote;
 188
 189                 if (signal_pending (current)) {
 190                         if (!bytes_written)
 191                                 bytes_written = -EINTR;
 192                         break;
 193                 }
 194
 195                 if (current->need_resched)
 196                         schedule ();
 197         }
 198
 199         kfree (kbuffer);
 200         pp_enable_irq (pp);
 201         return bytes_written;
 202 }
 203
 204 static void pp_irq (int irq, void * private, struct pt_regs * unused)
 205 {
 206         struct pp_struct * pp = (struct pp_struct *) private;
 207
 208         if (pp->irqresponse) {
 209                 parport_write_control (pp->pdev->port, pp->irqctl);
 210                 pp->irqresponse = 0;
 211         }
 212
 213         atomic_inc (&pp->irqc);
 214         wake_up_interruptible (&pp->irq_wait);
 215 }
 216
 217 static int register_device (int minor, struct pp_struct *pp)
 218 {
 219         struct parport * port;
 220         struct pardevice * pdev = NULL;
 221         char *name;
 222         int fl;
 223
 224         name = kmalloc (strlen (CHRDEV) + 3, GFP_KERNEL);
 225         if (name == NULL)
 226                 return -ENOMEM;
 227
 228         sprintf (name, CHRDEV "%x", minor);
 229         port = parport_enumerate (); /* FIXME: use attach/detach */
 230
 231         while (port && port->number != minor)
 232                 port = port->next;
 233
 234         if (!port) {
 235                 printk (KERN_WARNING "%s: no associated port!\n", name);
 236                 kfree (name);
 237                 return -ENXIO;
 238         }
 239
 240         fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
 241         pdev = parport_register_device (port, name, NULL, NULL, pp_irq, fl,
 242                                         pp);
 243
 244         if (!pdev) {
 245                 printk (KERN_WARNING "%s: failed to register device!\n", name);
 246                 kfree (name);
 247                 return -ENXIO;
 248         }
 249
 250         pp->pdev = pdev;
 251         printk (KERN_DEBUG "%s: registered pardevice\n", name);
 252         return 0;
 253 }
 254
 255 static enum ieee1284_phase init_phase (int mode)
 256 {
 257         switch (mode & ~(IEEE1284_DEVICEID
 258                          | IEEE1284_ADDR)) {
 259         case IEEE1284_MODE_NIBBLE:
 260         case IEEE1284_MODE_BYTE:
 261                 return IEEE1284_PH_REV_IDLE;
 262         }
 263         return IEEE1284_PH_FWD_IDLE;
 264 }
 265
 266 static int pp_ioctl(struct inode *inode, struct file *file,
 267                     unsigned int cmd, unsigned long arg)
 268 {
 269         unsigned int minor = MINOR(inode->i_rdev);
 270         struct pp_struct *pp = file->private_data;
 271         struct parport * port;
 272
 273         /* First handle the cases that don't take arguments. */
 274         if (cmd == PPCLAIM) {
 275                 struct ieee1284_info *info;
 276
 277                 if (pp->flags & PP_CLAIMED) {
 278                         printk (KERN_DEBUG CHRDEV
 279                                 "%x: you've already got it!\n", minor);
 280                         return -EINVAL;
 281                 }
 282
 283                 /* Deferred device registration. */
 284                 if (!pp->pdev) {
 285                         int err = register_device (minor, pp);
 286                         if (err)
 287                                 return err;
 288                 }
 289
 290                 parport_claim_or_block (pp->pdev);
 291                 pp->flags |= PP_CLAIMED;
 292
 293                 /* For interrupt-reporting to work, we need to be
 294                  * informed of each interrupt. */
 295                 pp_enable_irq (pp);
 296
 297                 /* We may need to fix up the state machine. */
 298                 info = &pp->pdev->port->ieee1284;
 299                 pp->saved_state.mode = info->mode;
 300                 pp->saved_state.phase = info->phase;
 301                 info->mode = pp->state.mode;
 302                 info->phase = pp->state.phase;
 303
 304                 return 0;
 305         }
 306
 307         if (cmd == PPEXCL) {
 308                 if (pp->pdev) {
 309                         printk (KERN_DEBUG CHRDEV "%x: too late for PPEXCL; "
 310                                 "already registered\n", minor);
 311                         if (pp->flags & PP_EXCL)
 312                                 /* But it's not really an error. */
 313                                 return 0;
 314                         /* There's no chance of making the driver happy. */
 315                         return -EINVAL;
 316                 }
 317
 318                 /* Just remember to register the device exclusively
 319                  * when we finally do the registration. */
 320                 pp->flags |= PP_EXCL;
 321                 return 0;
 322         }
 323
 324         if (cmd == PPSETMODE) {
 325                 int mode;
 326                 if (copy_from_user (&mode, (int *) arg, sizeof (mode)))
 327                         return -EFAULT;
 328                 /* FIXME: validate mode */
 329                 pp->state.mode = mode;
 330                 pp->state.phase = init_phase (mode);
 331
 332                 if (pp->flags & PP_CLAIMED) {
 333                         pp->pdev->port->ieee1284.mode = mode;
 334                         pp->pdev->port->ieee1284.phase = pp->state.phase;
 335                 }
 336
 337                 return 0;
 338         }
 339
 340         if (cmd == PPSETPHASE) {
 341                 int phase;
 342                 if (copy_from_user (&phase, (int *) arg, sizeof (phase)))
 343                         return -EFAULT;
 344                 /* FIXME: validate phase */
 345                 pp->state.phase = phase;
 346
 347                 if (pp->flags & PP_CLAIMED)
 348                         pp->pdev->port->ieee1284.phase = phase;
 349
 350                 return 0;
 351         }
 352
 353         /* Everything else requires the port to be claimed, so check
 354          * that now. */
 355         if ((pp->flags & PP_CLAIMED) == 0) {
 356                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 357                         minor);
 358                 return -EINVAL;
 359         }
 360
 361         port = pp->pdev->port;
 362         switch (cmd) {
 363                 struct ieee1284_info *info;
 364                 unsigned char reg;
 365                 unsigned char mask;
 366                 int mode;
 367                 int ret;
 368                 struct timeval par_timeout;
 369                 long to_jiffies;
 370
 371         case PPRSTATUS:
 372                 reg = parport_read_status (port);
 373                 return copy_to_user ((unsigned char *) arg, &reg,
 374                                      sizeof (reg));
 375
 376         case PPRDATA:
 377                 reg = parport_read_data (port);
 378                 return copy_to_user ((unsigned char *) arg, &reg,
 379                                      sizeof (reg));
 380
 381         case PPRCONTROL:
 382                 reg = parport_read_control (port);
 383                 return copy_to_user ((unsigned char *) arg, &reg,
 384                                      sizeof (reg));
 385
 386         case PPYIELD:
 387                 parport_yield_blocking (pp->pdev);
 388                 return 0;
 389
 390         case PPRELEASE:
 391                 /* Save the state machine's state. */
 392                 info = &pp->pdev->port->ieee1284;
 393                 pp->state.mode = info->mode;
 394                 pp->state.phase = info->phase;
 395                 info->mode = pp->saved_state.mode;
 396                 info->phase = pp->saved_state.phase;
 397                 parport_release (pp->pdev);
 398                 pp->flags &= ~PP_CLAIMED;
 399                 return 0;
 400
 401         case PPWCONTROL:
 402                 if (copy_from_user (&reg, (unsigned char *) arg, sizeof (reg)))
 403                         return -EFAULT;
 404                 parport_write_control (port, reg);
 405                 return 0;
 406
 407         case PPWDATA:
 408                 if (copy_from_user (&reg, (unsigned char *) arg, sizeof (reg)))
 409                         return -EFAULT;
 410                 parport_write_data (port, reg);
 411                 return 0;
 412
 413         case PPFCONTROL:
 414                 if (copy_from_user (&mask, (unsigned char *) arg,
 415                                     sizeof (mask)))
 416                         return -EFAULT;
 417                 if (copy_from_user (&reg, 1 + (unsigned char *) arg,
 418                                     sizeof (reg)))
 419                         return -EFAULT;
 420                 parport_frob_control (port, mask, reg);
 421                 return 0;
 422
 423         case PPDATADIR:
 424                 if (copy_from_user (&mode, (int *) arg, sizeof (mode)))
 425                         return -EFAULT;
 426                 if (mode)
 427                         port->ops->data_reverse (port);
 428                 else
 429                         port->ops->data_forward (port);
 430                 return 0;
 431
 432         case PPNEGOT:
 433                 if (copy_from_user (&mode, (int *) arg, sizeof (mode)))
 434                         return -EFAULT;
 435                 switch ((ret = parport_negotiate (port, mode))) {
 436                 case 0: break;
 437                 case -1: /* handshake failed, peripheral not IEEE 1284 */
 438                         ret = -EIO;
 439                         break;
 440                 case 1:  /* handshake succeeded, peripheral rejected mode */
 441                         ret = -ENXIO;
 442                         break;
 443                 }
 444                 pp_enable_irq (pp);
 445                 return ret;
 446
 447         case PPWCTLONIRQ:
 448                 if (copy_from_user (&reg, (unsigned char *) arg,
 449                                     sizeof (reg)))
 450                         return -EFAULT;
 451
 452                 /* Remember what to set the control lines to, for next
 453                  * time we get an interrupt. */
 454                 pp->irqctl = reg;
 455                 pp->irqresponse = 1;
 456                 return 0;
 457
 458         case PPCLRIRQ:
 459                 ret = atomic_read (&pp->irqc);
 460                 if (copy_to_user ((int *) arg, &ret, sizeof (ret)))
 461                         return -EFAULT;
 462                 atomic_sub (ret, &pp->irqc);
 463                 return 0;
 464
 465         case PPSETTIME:
 466                 if (copy_from_user (&par_timeout, (struct timeval *)arg,
 467                                     sizeof(struct timeval))) {
 468                         return -EFAULT;
 469                 }
 470                 /* Convert to jiffies, place in pp->pdev->timeout */
 471                 if ((par_timeout.tv_sec < 0) || (par_timeout.tv_usec < 0)) {
 472                         return -EINVAL;
 473                 }
 474                 to_jiffies = ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
 475                 to_jiffies += par_timeout.tv_sec * (long)HZ;
 476                 if (to_jiffies <= 0) {
 477                         return -EINVAL;
 478                 }
 479                 pp->pdev->timeout = to_jiffies;
 480                 return 0;
 481
 482         case PPGETTIME:
 483                 to_jiffies = pp->pdev->timeout;
 484                 par_timeout.tv_sec = to_jiffies / HZ;
 485                 par_timeout.tv_usec = (to_jiffies % (long)HZ) * (1000000/HZ);
 486                 if (copy_to_user ((struct timeval *)arg, &par_timeout,
 487                                   sizeof(struct timeval))) {
 488                         return -EFAULT;
 489                 }
 490                 return 0;
 491
 492         default:
 493                 printk (KERN_DEBUG CHRDEV "%x: What? (cmd=0x%x)\n", minor,
 494                         cmd);
 495                 return -EINVAL;
 496         }
 497
 498         /* Keep the compiler happy */
 499         return 0;
 500 }
 501
 502 static int pp_open (struct inode * inode, struct file * file)
 503 {
 504         unsigned int minor = MINOR (inode->i_rdev);
 505         struct pp_struct *pp;
 506
 507         if (minor >= PARPORT_MAX)
 508                 return -ENXIO;
 509
 510         MOD_INC_USE_COUNT;
 511
 512         pp = kmalloc (sizeof (struct pp_struct), GFP_KERNEL);
 513         if (!pp) {
 514                 MOD_DEC_USE_COUNT;
 515                 return -ENOMEM;
 516         }
 517
 518         pp->state.mode = IEEE1284_MODE_COMPAT;
 519         pp->state.phase = init_phase (pp->state.mode);
 520         pp->flags = 0;
 521         pp->irqresponse = 0;
 522         atomic_set (&pp->irqc, 0);
 523         init_waitqueue_head (&pp->irq_wait);
 524
 525         /* Defer the actual device registration until the first claim.
 526          * That way, we know whether or not the driver wants to have
 527          * exclusive access to the port (PPEXCL).
 528          */
 529         pp->pdev = NULL;
 530         file->private_data = pp;
 531
 532         return 0;
 533 }
 534
 535 static int pp_release (struct inode * inode, struct file * file)
 536 {
 537         unsigned int minor = MINOR (inode->i_rdev);
 538         struct pp_struct *pp = file->private_data;
 539
 540         if (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT) {
 541                 if (!(pp->flags & PP_CLAIMED)) {
 542                         parport_claim_or_block (pp->pdev);
 543                         pp->flags |= PP_CLAIMED;
 544                 }
 545                 parport_negotiate (pp->pdev->port, IEEE1284_MODE_COMPAT);
 546                 printk (KERN_DEBUG CHRDEV
 547                         "%x: negotiated back to compatibility mode because "
 548                         "user-space forgot\n", minor);
 549         }
 550
 551         if (pp->flags & PP_CLAIMED) {
 552                 parport_release (pp->pdev);
 553                 printk (KERN_DEBUG CHRDEV "%x: released pardevice because "
 554                         "user-space forgot\n", minor);
 555         }
 556
 557         if (pp->pdev) {
 558                 const char *name = pp->pdev->name;
 559                 parport_unregister_device (pp->pdev);
 560                 kfree (name);
 561                 pp->pdev = NULL;
 562                 printk (KERN_DEBUG CHRDEV "%x: unregistered pardevice\n",
 563                         minor);
 564         }
 565
 566         kfree (pp);
 567
 568         MOD_DEC_USE_COUNT;
 569         return 0;
 570 }
 571
 572 static unsigned int pp_poll (struct file * file, poll_table * wait)
 573 {
 574         struct pp_struct *pp = file->private_data;
 575         unsigned int mask = 0;
 576
 577         if (atomic_read (&pp->irqc))
 578                 mask |= POLLIN | POLLRDNORM;
 579
 580         poll_wait (file, &pp->irq_wait, wait);
 581         return mask;
 582 }
 583
 584 static struct file_operations pp_fops = {
 585         llseek:         pp_lseek,
 586         read:           pp_read,
 587         write:          pp_write,
 588         poll:           pp_poll,
 589         ioctl:          pp_ioctl,
 590         open:           pp_open,
 591         release:        pp_release,
 592 };
 593
 594 static devfs_handle_t devfs_handle = NULL;
 595
 596 static int __init ppdev_init (void)
 597 {
 598         if (devfs_register_chrdev (PP_MAJOR, CHRDEV, &pp_fops)) {
 599                 printk (KERN_WARNING CHRDEV ": unable to get major %d\n",
 600                         PP_MAJOR);
 601                 return -EIO;
 602         }
 603         devfs_handle = devfs_mk_dir (NULL, "parports", 0, NULL);
 604         devfs_register_series (devfs_handle, "%u", PARPORT_MAX,
 605                                DEVFS_FL_DEFAULT, PP_MAJOR, 0,
 606                                S_IFCHR | S_IRUGO | S_IWUGO, 0, 0,
 607                                &pp_fops, NULL);
 608
 609         printk (KERN_INFO PP_VERSION "\n");
 610         return 0;
 611 }
 612
 613 static void __exit ppdev_cleanup (void)
 614 {
 615         /* Clean up all parport stuff */
 616         devfs_unregister (devfs_handle);
 617         devfs_unregister_chrdev (PP_MAJOR, CHRDEV);
 618 }
 619
 620 module_init(ppdev_init);
 621 module_exit(ppdev_cleanup);