xref: /openbmc/linux/drivers/char/ppdev.c (revision de2bdb3d)
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.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 };
88 
89 /* pp_struct.flags bitfields */
90 #define PP_CLAIMED    (1<<0)
91 #define PP_EXCL       (1<<1)
92 
93 /* Other constants */
94 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
95 #define PP_BUFFER_SIZE 1024
96 #define PARDEVICE_MAX 8
97 
98 /* ROUND_UP macro from fs/select.c */
99 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
100 
101 static DEFINE_MUTEX(pp_do_mutex);
102 
103 /* define fixed sized ioctl cmd for y2038 migration */
104 #define PPGETTIME32	_IOR(PP_IOCTL, 0x95, s32[2])
105 #define PPSETTIME32	_IOW(PP_IOCTL, 0x96, s32[2])
106 #define PPGETTIME64	_IOR(PP_IOCTL, 0x95, s64[2])
107 #define PPSETTIME64	_IOW(PP_IOCTL, 0x96, s64[2])
108 
109 static inline void pp_enable_irq(struct pp_struct *pp)
110 {
111 	struct parport *port = pp->pdev->port;
112 
113 	port->ops->enable_irq(port);
114 }
115 
116 static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
117 		       loff_t *ppos)
118 {
119 	unsigned int minor = iminor(file_inode(file));
120 	struct pp_struct *pp = file->private_data;
121 	char *kbuffer;
122 	ssize_t bytes_read = 0;
123 	struct parport *pport;
124 	int mode;
125 
126 	if (!(pp->flags & PP_CLAIMED)) {
127 		/* Don't have the port claimed */
128 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
129 		return -EINVAL;
130 	}
131 
132 	/* Trivial case. */
133 	if (count == 0)
134 		return 0;
135 
136 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
137 	if (!kbuffer)
138 		return -ENOMEM;
139 	pport = pp->pdev->port;
140 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
141 
142 	parport_set_timeout(pp->pdev,
143 			    (file->f_flags & O_NONBLOCK) ?
144 			    PARPORT_INACTIVITY_O_NONBLOCK :
145 			    pp->default_inactivity);
146 
147 	while (bytes_read == 0) {
148 		ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
149 
150 		if (mode == IEEE1284_MODE_EPP) {
151 			/* various specials for EPP mode */
152 			int flags = 0;
153 			size_t (*fn)(struct parport *, void *, size_t, int);
154 
155 			if (pp->flags & PP_W91284PIC)
156 				flags |= PARPORT_W91284PIC;
157 			if (pp->flags & PP_FASTREAD)
158 				flags |= PARPORT_EPP_FAST;
159 			if (pport->ieee1284.mode & IEEE1284_ADDR)
160 				fn = pport->ops->epp_read_addr;
161 			else
162 				fn = pport->ops->epp_read_data;
163 			bytes_read = (*fn)(pport, kbuffer, need, flags);
164 		} else {
165 			bytes_read = parport_read(pport, kbuffer, need);
166 		}
167 
168 		if (bytes_read != 0)
169 			break;
170 
171 		if (file->f_flags & O_NONBLOCK) {
172 			bytes_read = -EAGAIN;
173 			break;
174 		}
175 
176 		if (signal_pending(current)) {
177 			bytes_read = -ERESTARTSYS;
178 			break;
179 		}
180 
181 		cond_resched();
182 	}
183 
184 	parport_set_timeout(pp->pdev, pp->default_inactivity);
185 
186 	if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
187 		bytes_read = -EFAULT;
188 
189 	kfree(kbuffer);
190 	pp_enable_irq(pp);
191 	return bytes_read;
192 }
193 
194 static ssize_t pp_write(struct file *file, const char __user *buf,
195 			size_t count, loff_t *ppos)
196 {
197 	unsigned int minor = iminor(file_inode(file));
198 	struct pp_struct *pp = file->private_data;
199 	char *kbuffer;
200 	ssize_t bytes_written = 0;
201 	ssize_t wrote;
202 	int mode;
203 	struct parport *pport;
204 
205 	if (!(pp->flags & PP_CLAIMED)) {
206 		/* Don't have the port claimed */
207 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
208 		return -EINVAL;
209 	}
210 
211 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
212 	if (!kbuffer)
213 		return -ENOMEM;
214 
215 	pport = pp->pdev->port;
216 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
217 
218 	parport_set_timeout(pp->pdev,
219 			    (file->f_flags & O_NONBLOCK) ?
220 			    PARPORT_INACTIVITY_O_NONBLOCK :
221 			    pp->default_inactivity);
222 
223 	while (bytes_written < count) {
224 		ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
225 
226 		if (copy_from_user(kbuffer, buf + bytes_written, n)) {
227 			bytes_written = -EFAULT;
228 			break;
229 		}
230 
231 		if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
232 			/* do a fast EPP write */
233 			if (pport->ieee1284.mode & IEEE1284_ADDR) {
234 				wrote = pport->ops->epp_write_addr(pport,
235 					kbuffer, n, PARPORT_EPP_FAST);
236 			} else {
237 				wrote = pport->ops->epp_write_data(pport,
238 					kbuffer, n, PARPORT_EPP_FAST);
239 			}
240 		} else {
241 			wrote = parport_write(pp->pdev->port, kbuffer, n);
242 		}
243 
244 		if (wrote <= 0) {
245 			if (!bytes_written)
246 				bytes_written = wrote;
247 			break;
248 		}
249 
250 		bytes_written += wrote;
251 
252 		if (file->f_flags & O_NONBLOCK) {
253 			if (!bytes_written)
254 				bytes_written = -EAGAIN;
255 			break;
256 		}
257 
258 		if (signal_pending(current))
259 			break;
260 
261 		cond_resched();
262 	}
263 
264 	parport_set_timeout(pp->pdev, pp->default_inactivity);
265 
266 	kfree(kbuffer);
267 	pp_enable_irq(pp);
268 	return bytes_written;
269 }
270 
271 static void pp_irq(void *private)
272 {
273 	struct pp_struct *pp = private;
274 
275 	if (pp->irqresponse) {
276 		parport_write_control(pp->pdev->port, pp->irqctl);
277 		pp->irqresponse = 0;
278 	}
279 
280 	atomic_inc(&pp->irqc);
281 	wake_up_interruptible(&pp->irq_wait);
282 }
283 
284 static int register_device(int minor, struct pp_struct *pp)
285 {
286 	struct parport *port;
287 	struct pardevice *pdev = NULL;
288 	char *name;
289 	struct pardev_cb ppdev_cb;
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 		printk(KERN_WARNING "%s: no associated port!\n", name);
298 		kfree(name);
299 		return -ENXIO;
300 	}
301 
302 	memset(&ppdev_cb, 0, sizeof(ppdev_cb));
303 	ppdev_cb.irq_func = pp_irq;
304 	ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
305 	ppdev_cb.private = pp;
306 	pdev = parport_register_dev_model(port, name, &ppdev_cb, minor);
307 	parport_put_port(port);
308 
309 	if (!pdev) {
310 		printk(KERN_WARNING "%s: failed to register device!\n", name);
311 		kfree(name);
312 		return -ENXIO;
313 	}
314 
315 	pp->pdev = pdev;
316 	dev_dbg(&pdev->dev, "registered pardevice\n");
317 	return 0;
318 }
319 
320 static enum ieee1284_phase init_phase(int mode)
321 {
322 	switch (mode & ~(IEEE1284_DEVICEID
323 			 | IEEE1284_ADDR)) {
324 	case IEEE1284_MODE_NIBBLE:
325 	case IEEE1284_MODE_BYTE:
326 		return IEEE1284_PH_REV_IDLE;
327 	}
328 	return IEEE1284_PH_FWD_IDLE;
329 }
330 
331 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
332 {
333 	long to_jiffies;
334 
335 	if ((tv_sec < 0) || (tv_usec < 0))
336 		return -EINVAL;
337 
338 	to_jiffies = usecs_to_jiffies(tv_usec);
339 	to_jiffies += tv_sec * HZ;
340 	if (to_jiffies <= 0)
341 		return -EINVAL;
342 
343 	pdev->timeout = to_jiffies;
344 	return 0;
345 }
346 
347 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
348 {
349 	unsigned int minor = iminor(file_inode(file));
350 	struct pp_struct *pp = file->private_data;
351 	struct parport *port;
352 	void __user *argp = (void __user *)arg;
353 
354 	/* First handle the cases that don't take arguments. */
355 	switch (cmd) {
356 	case PPCLAIM:
357 	    {
358 		struct ieee1284_info *info;
359 		int ret;
360 
361 		if (pp->flags & PP_CLAIMED) {
362 			dev_dbg(&pp->pdev->dev, "you've already got it!\n");
363 			return -EINVAL;
364 		}
365 
366 		/* Deferred device registration. */
367 		if (!pp->pdev) {
368 			int err = register_device(minor, pp);
369 
370 			if (err)
371 				return err;
372 		}
373 
374 		ret = parport_claim_or_block(pp->pdev);
375 		if (ret < 0)
376 			return ret;
377 
378 		pp->flags |= PP_CLAIMED;
379 
380 		/* For interrupt-reporting to work, we need to be
381 		 * informed of each interrupt. */
382 		pp_enable_irq(pp);
383 
384 		/* We may need to fix up the state machine. */
385 		info = &pp->pdev->port->ieee1284;
386 		pp->saved_state.mode = info->mode;
387 		pp->saved_state.phase = info->phase;
388 		info->mode = pp->state.mode;
389 		info->phase = pp->state.phase;
390 		pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
391 		parport_set_timeout(pp->pdev, pp->default_inactivity);
392 
393 		return 0;
394 	    }
395 	case PPEXCL:
396 		if (pp->pdev) {
397 			dev_dbg(&pp->pdev->dev,
398 				"too late for PPEXCL; already registered\n");
399 			if (pp->flags & PP_EXCL)
400 				/* But it's not really an error. */
401 				return 0;
402 			/* There's no chance of making the driver happy. */
403 			return -EINVAL;
404 		}
405 
406 		/* Just remember to register the device exclusively
407 		 * when we finally do the registration. */
408 		pp->flags |= PP_EXCL;
409 		return 0;
410 	case PPSETMODE:
411 	    {
412 		int mode;
413 
414 		if (copy_from_user(&mode, argp, sizeof(mode)))
415 			return -EFAULT;
416 		/* FIXME: validate mode */
417 		pp->state.mode = mode;
418 		pp->state.phase = init_phase(mode);
419 
420 		if (pp->flags & PP_CLAIMED) {
421 			pp->pdev->port->ieee1284.mode = mode;
422 			pp->pdev->port->ieee1284.phase = pp->state.phase;
423 		}
424 
425 		return 0;
426 	    }
427 	case PPGETMODE:
428 	    {
429 		int mode;
430 
431 		if (pp->flags & PP_CLAIMED)
432 			mode = pp->pdev->port->ieee1284.mode;
433 		else
434 			mode = pp->state.mode;
435 
436 		if (copy_to_user(argp, &mode, sizeof(mode)))
437 			return -EFAULT;
438 		return 0;
439 	    }
440 	case PPSETPHASE:
441 	    {
442 		int phase;
443 
444 		if (copy_from_user(&phase, argp, sizeof(phase)))
445 			return -EFAULT;
446 
447 		/* FIXME: validate phase */
448 		pp->state.phase = phase;
449 
450 		if (pp->flags & PP_CLAIMED)
451 			pp->pdev->port->ieee1284.phase = phase;
452 
453 		return 0;
454 	    }
455 	case PPGETPHASE:
456 	    {
457 		int phase;
458 
459 		if (pp->flags & PP_CLAIMED)
460 			phase = pp->pdev->port->ieee1284.phase;
461 		else
462 			phase = pp->state.phase;
463 		if (copy_to_user(argp, &phase, sizeof(phase)))
464 			return -EFAULT;
465 		return 0;
466 	    }
467 	case PPGETMODES:
468 	    {
469 		unsigned int modes;
470 
471 		port = parport_find_number(minor);
472 		if (!port)
473 			return -ENODEV;
474 
475 		modes = port->modes;
476 		parport_put_port(port);
477 		if (copy_to_user(argp, &modes, sizeof(modes)))
478 			return -EFAULT;
479 		return 0;
480 	    }
481 	case PPSETFLAGS:
482 	    {
483 		int uflags;
484 
485 		if (copy_from_user(&uflags, argp, sizeof(uflags)))
486 			return -EFAULT;
487 		pp->flags &= ~PP_FLAGMASK;
488 		pp->flags |= (uflags & PP_FLAGMASK);
489 		return 0;
490 	    }
491 	case PPGETFLAGS:
492 	    {
493 		int uflags;
494 
495 		uflags = pp->flags & PP_FLAGMASK;
496 		if (copy_to_user(argp, &uflags, sizeof(uflags)))
497 			return -EFAULT;
498 		return 0;
499 	    }
500 	}	/* end switch() */
501 
502 	/* Everything else requires the port to be claimed, so check
503 	 * that now. */
504 	if ((pp->flags & PP_CLAIMED) == 0) {
505 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
506 		return -EINVAL;
507 	}
508 
509 	port = pp->pdev->port;
510 	switch (cmd) {
511 		struct ieee1284_info *info;
512 		unsigned char reg;
513 		unsigned char mask;
514 		int mode;
515 		s32 time32[2];
516 		s64 time64[2];
517 		struct timespec64 ts;
518 		int ret;
519 
520 	case PPRSTATUS:
521 		reg = parport_read_status(port);
522 		if (copy_to_user(argp, &reg, sizeof(reg)))
523 			return -EFAULT;
524 		return 0;
525 	case PPRDATA:
526 		reg = parport_read_data(port);
527 		if (copy_to_user(argp, &reg, sizeof(reg)))
528 			return -EFAULT;
529 		return 0;
530 	case PPRCONTROL:
531 		reg = parport_read_control(port);
532 		if (copy_to_user(argp, &reg, sizeof(reg)))
533 			return -EFAULT;
534 		return 0;
535 	case PPYIELD:
536 		parport_yield_blocking(pp->pdev);
537 		return 0;
538 
539 	case PPRELEASE:
540 		/* Save the state machine's state. */
541 		info = &pp->pdev->port->ieee1284;
542 		pp->state.mode = info->mode;
543 		pp->state.phase = info->phase;
544 		info->mode = pp->saved_state.mode;
545 		info->phase = pp->saved_state.phase;
546 		parport_release(pp->pdev);
547 		pp->flags &= ~PP_CLAIMED;
548 		return 0;
549 
550 	case PPWCONTROL:
551 		if (copy_from_user(&reg, argp, sizeof(reg)))
552 			return -EFAULT;
553 		parport_write_control(port, reg);
554 		return 0;
555 
556 	case PPWDATA:
557 		if (copy_from_user(&reg, argp, sizeof(reg)))
558 			return -EFAULT;
559 		parport_write_data(port, reg);
560 		return 0;
561 
562 	case PPFCONTROL:
563 		if (copy_from_user(&mask, argp,
564 				   sizeof(mask)))
565 			return -EFAULT;
566 		if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
567 				   sizeof(reg)))
568 			return -EFAULT;
569 		parport_frob_control(port, mask, reg);
570 		return 0;
571 
572 	case PPDATADIR:
573 		if (copy_from_user(&mode, argp, sizeof(mode)))
574 			return -EFAULT;
575 		if (mode)
576 			port->ops->data_reverse(port);
577 		else
578 			port->ops->data_forward(port);
579 		return 0;
580 
581 	case PPNEGOT:
582 		if (copy_from_user(&mode, argp, sizeof(mode)))
583 			return -EFAULT;
584 		switch ((ret = parport_negotiate(port, mode))) {
585 		case 0: break;
586 		case -1: /* handshake failed, peripheral not IEEE 1284 */
587 			ret = -EIO;
588 			break;
589 		case 1:  /* handshake succeeded, peripheral rejected mode */
590 			ret = -ENXIO;
591 			break;
592 		}
593 		pp_enable_irq(pp);
594 		return ret;
595 
596 	case PPWCTLONIRQ:
597 		if (copy_from_user(&reg, argp, sizeof(reg)))
598 			return -EFAULT;
599 
600 		/* Remember what to set the control lines to, for next
601 		 * time we get an interrupt. */
602 		pp->irqctl = reg;
603 		pp->irqresponse = 1;
604 		return 0;
605 
606 	case PPCLRIRQ:
607 		ret = atomic_read(&pp->irqc);
608 		if (copy_to_user(argp, &ret, sizeof(ret)))
609 			return -EFAULT;
610 		atomic_sub(ret, &pp->irqc);
611 		return 0;
612 
613 	case PPSETTIME32:
614 		if (copy_from_user(time32, argp, sizeof(time32)))
615 			return -EFAULT;
616 
617 		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
618 
619 	case PPSETTIME64:
620 		if (copy_from_user(time64, argp, sizeof(time64)))
621 			return -EFAULT;
622 
623 		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
624 
625 	case PPGETTIME32:
626 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
627 		time32[0] = ts.tv_sec;
628 		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
629 		if ((time32[0] < 0) || (time32[1] < 0))
630 			return -EINVAL;
631 
632 		if (copy_to_user(argp, time32, sizeof(time32)))
633 			return -EFAULT;
634 
635 		return 0;
636 
637 	case PPGETTIME64:
638 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
639 		time64[0] = ts.tv_sec;
640 		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
641 		if ((time64[0] < 0) || (time64[1] < 0))
642 			return -EINVAL;
643 
644 		if (copy_to_user(argp, time64, sizeof(time64)))
645 			return -EFAULT;
646 
647 		return 0;
648 
649 	default:
650 		dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
651 		return -EINVAL;
652 	}
653 
654 	/* Keep the compiler happy */
655 	return 0;
656 }
657 
658 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
659 {
660 	long ret;
661 
662 	mutex_lock(&pp_do_mutex);
663 	ret = pp_do_ioctl(file, cmd, arg);
664 	mutex_unlock(&pp_do_mutex);
665 	return ret;
666 }
667 
668 #ifdef CONFIG_COMPAT
669 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
670 			    unsigned long arg)
671 {
672 	return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
673 }
674 #endif
675 
676 static int pp_open(struct inode *inode, struct file *file)
677 {
678 	unsigned int minor = iminor(inode);
679 	struct pp_struct *pp;
680 
681 	if (minor >= PARPORT_MAX)
682 		return -ENXIO;
683 
684 	pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
685 	if (!pp)
686 		return -ENOMEM;
687 
688 	pp->state.mode = IEEE1284_MODE_COMPAT;
689 	pp->state.phase = init_phase(pp->state.mode);
690 	pp->flags = 0;
691 	pp->irqresponse = 0;
692 	atomic_set(&pp->irqc, 0);
693 	init_waitqueue_head(&pp->irq_wait);
694 
695 	/* Defer the actual device registration until the first claim.
696 	 * That way, we know whether or not the driver wants to have
697 	 * exclusive access to the port (PPEXCL).
698 	 */
699 	pp->pdev = NULL;
700 	file->private_data = pp;
701 
702 	return 0;
703 }
704 
705 static int pp_release(struct inode *inode, struct file *file)
706 {
707 	unsigned int minor = iminor(inode);
708 	struct pp_struct *pp = file->private_data;
709 	int compat_negot;
710 
711 	compat_negot = 0;
712 	if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
713 	    (pp->state.mode != IEEE1284_MODE_COMPAT)) {
714 		struct ieee1284_info *info;
715 
716 		/* parport released, but not in compatibility mode */
717 		parport_claim_or_block(pp->pdev);
718 		pp->flags |= PP_CLAIMED;
719 		info = &pp->pdev->port->ieee1284;
720 		pp->saved_state.mode = info->mode;
721 		pp->saved_state.phase = info->phase;
722 		info->mode = pp->state.mode;
723 		info->phase = pp->state.phase;
724 		compat_negot = 1;
725 	} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
726 	    (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
727 		compat_negot = 2;
728 	}
729 	if (compat_negot) {
730 		parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
731 		dev_dbg(&pp->pdev->dev,
732 			"negotiated back to compatibility mode because user-space forgot\n");
733 	}
734 
735 	if (pp->flags & PP_CLAIMED) {
736 		struct ieee1284_info *info;
737 
738 		info = &pp->pdev->port->ieee1284;
739 		pp->state.mode = info->mode;
740 		pp->state.phase = info->phase;
741 		info->mode = pp->saved_state.mode;
742 		info->phase = pp->saved_state.phase;
743 		parport_release(pp->pdev);
744 		if (compat_negot != 1) {
745 			pr_debug(CHRDEV "%x: released pardevice "
746 				"because user-space forgot\n", minor);
747 		}
748 	}
749 
750 	if (pp->pdev) {
751 		const char *name = pp->pdev->name;
752 
753 		parport_unregister_device(pp->pdev);
754 		kfree(name);
755 		pp->pdev = NULL;
756 		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
757 	}
758 
759 	kfree(pp);
760 
761 	return 0;
762 }
763 
764 /* No kernel lock held - fine */
765 static unsigned int pp_poll(struct file *file, poll_table *wait)
766 {
767 	struct pp_struct *pp = file->private_data;
768 	unsigned int mask = 0;
769 
770 	poll_wait(file, &pp->irq_wait, wait);
771 	if (atomic_read(&pp->irqc))
772 		mask |= POLLIN | POLLRDNORM;
773 
774 	return mask;
775 }
776 
777 static struct class *ppdev_class;
778 
779 static const struct file_operations pp_fops = {
780 	.owner		= THIS_MODULE,
781 	.llseek		= no_llseek,
782 	.read		= pp_read,
783 	.write		= pp_write,
784 	.poll		= pp_poll,
785 	.unlocked_ioctl	= pp_ioctl,
786 #ifdef CONFIG_COMPAT
787 	.compat_ioctl   = pp_compat_ioctl,
788 #endif
789 	.open		= pp_open,
790 	.release	= pp_release,
791 };
792 
793 static void pp_attach(struct parport *port)
794 {
795 	device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
796 		      NULL, "parport%d", port->number);
797 }
798 
799 static void pp_detach(struct parport *port)
800 {
801 	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
802 }
803 
804 static int pp_probe(struct pardevice *par_dev)
805 {
806 	struct device_driver *drv = par_dev->dev.driver;
807 	int len = strlen(drv->name);
808 
809 	if (strncmp(par_dev->name, drv->name, len))
810 		return -ENODEV;
811 
812 	return 0;
813 }
814 
815 static struct parport_driver pp_driver = {
816 	.name		= CHRDEV,
817 	.probe		= pp_probe,
818 	.match_port	= pp_attach,
819 	.detach		= pp_detach,
820 	.devmodel	= true,
821 };
822 
823 static int __init ppdev_init(void)
824 {
825 	int err = 0;
826 
827 	if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
828 		printk(KERN_WARNING CHRDEV ": unable to get major %d\n",
829 		       PP_MAJOR);
830 		return -EIO;
831 	}
832 	ppdev_class = class_create(THIS_MODULE, CHRDEV);
833 	if (IS_ERR(ppdev_class)) {
834 		err = PTR_ERR(ppdev_class);
835 		goto out_chrdev;
836 	}
837 	err = parport_register_driver(&pp_driver);
838 	if (err < 0) {
839 		printk(KERN_WARNING CHRDEV ": unable to register with parport\n");
840 		goto out_class;
841 	}
842 
843 	printk(KERN_INFO PP_VERSION "\n");
844 	goto out;
845 
846 out_class:
847 	class_destroy(ppdev_class);
848 out_chrdev:
849 	unregister_chrdev(PP_MAJOR, CHRDEV);
850 out:
851 	return err;
852 }
853 
854 static void __exit ppdev_cleanup(void)
855 {
856 	/* Clean up all parport stuff */
857 	parport_unregister_driver(&pp_driver);
858 	class_destroy(ppdev_class);
859 	unregister_chrdev(PP_MAJOR, CHRDEV);
860 }
861 
862 module_init(ppdev_init);
863 module_exit(ppdev_cleanup);
864 
865 MODULE_LICENSE("GPL");
866 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);
867