xref: /openbmc/linux/drivers/char/ppdev.c (revision cfbb9be8)
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 		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
627 
628 	case PPSETTIME64:
629 		if (copy_from_user(time64, argp, sizeof(time64)))
630 			return -EFAULT;
631 
632 		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
633 
634 	case PPGETTIME32:
635 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
636 		time32[0] = ts.tv_sec;
637 		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
638 		if ((time32[0] < 0) || (time32[1] < 0))
639 			return -EINVAL;
640 
641 		if (copy_to_user(argp, time32, sizeof(time32)))
642 			return -EFAULT;
643 
644 		return 0;
645 
646 	case PPGETTIME64:
647 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
648 		time64[0] = ts.tv_sec;
649 		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
650 		if ((time64[0] < 0) || (time64[1] < 0))
651 			return -EINVAL;
652 
653 		if (copy_to_user(argp, time64, sizeof(time64)))
654 			return -EFAULT;
655 
656 		return 0;
657 
658 	default:
659 		dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
660 		return -EINVAL;
661 	}
662 
663 	/* Keep the compiler happy */
664 	return 0;
665 }
666 
667 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
668 {
669 	long ret;
670 
671 	mutex_lock(&pp_do_mutex);
672 	ret = pp_do_ioctl(file, cmd, arg);
673 	mutex_unlock(&pp_do_mutex);
674 	return ret;
675 }
676 
677 #ifdef CONFIG_COMPAT
678 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
679 			    unsigned long arg)
680 {
681 	return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
682 }
683 #endif
684 
685 static int pp_open(struct inode *inode, struct file *file)
686 {
687 	unsigned int minor = iminor(inode);
688 	struct pp_struct *pp;
689 
690 	if (minor >= PARPORT_MAX)
691 		return -ENXIO;
692 
693 	pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
694 	if (!pp)
695 		return -ENOMEM;
696 
697 	pp->state.mode = IEEE1284_MODE_COMPAT;
698 	pp->state.phase = init_phase(pp->state.mode);
699 	pp->flags = 0;
700 	pp->irqresponse = 0;
701 	atomic_set(&pp->irqc, 0);
702 	init_waitqueue_head(&pp->irq_wait);
703 
704 	/* Defer the actual device registration until the first claim.
705 	 * That way, we know whether or not the driver wants to have
706 	 * exclusive access to the port (PPEXCL).
707 	 */
708 	pp->pdev = NULL;
709 	file->private_data = pp;
710 
711 	return 0;
712 }
713 
714 static int pp_release(struct inode *inode, struct file *file)
715 {
716 	unsigned int minor = iminor(inode);
717 	struct pp_struct *pp = file->private_data;
718 	int compat_negot;
719 
720 	compat_negot = 0;
721 	if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
722 	    (pp->state.mode != IEEE1284_MODE_COMPAT)) {
723 		struct ieee1284_info *info;
724 
725 		/* parport released, but not in compatibility mode */
726 		parport_claim_or_block(pp->pdev);
727 		pp->flags |= PP_CLAIMED;
728 		info = &pp->pdev->port->ieee1284;
729 		pp->saved_state.mode = info->mode;
730 		pp->saved_state.phase = info->phase;
731 		info->mode = pp->state.mode;
732 		info->phase = pp->state.phase;
733 		compat_negot = 1;
734 	} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
735 	    (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
736 		compat_negot = 2;
737 	}
738 	if (compat_negot) {
739 		parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
740 		dev_dbg(&pp->pdev->dev,
741 			"negotiated back to compatibility mode because user-space forgot\n");
742 	}
743 
744 	if (pp->flags & PP_CLAIMED) {
745 		struct ieee1284_info *info;
746 
747 		info = &pp->pdev->port->ieee1284;
748 		pp->state.mode = info->mode;
749 		pp->state.phase = info->phase;
750 		info->mode = pp->saved_state.mode;
751 		info->phase = pp->saved_state.phase;
752 		parport_release(pp->pdev);
753 		if (compat_negot != 1) {
754 			pr_debug(CHRDEV "%x: released pardevice "
755 				"because user-space forgot\n", minor);
756 		}
757 	}
758 
759 	if (pp->pdev) {
760 		parport_unregister_device(pp->pdev);
761 		ida_simple_remove(&ida_index, pp->index);
762 		pp->pdev = NULL;
763 		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
764 	}
765 
766 	kfree(pp);
767 
768 	return 0;
769 }
770 
771 /* No kernel lock held - fine */
772 static __poll_t pp_poll(struct file *file, poll_table *wait)
773 {
774 	struct pp_struct *pp = file->private_data;
775 	__poll_t mask = 0;
776 
777 	poll_wait(file, &pp->irq_wait, wait);
778 	if (atomic_read(&pp->irqc))
779 		mask |= EPOLLIN | EPOLLRDNORM;
780 
781 	return mask;
782 }
783 
784 static struct class *ppdev_class;
785 
786 static const struct file_operations pp_fops = {
787 	.owner		= THIS_MODULE,
788 	.llseek		= no_llseek,
789 	.read		= pp_read,
790 	.write		= pp_write,
791 	.poll		= pp_poll,
792 	.unlocked_ioctl	= pp_ioctl,
793 #ifdef CONFIG_COMPAT
794 	.compat_ioctl   = pp_compat_ioctl,
795 #endif
796 	.open		= pp_open,
797 	.release	= pp_release,
798 };
799 
800 static void pp_attach(struct parport *port)
801 {
802 	struct device *ret;
803 
804 	if (devices[port->number])
805 		return;
806 
807 	ret = device_create(ppdev_class, port->dev,
808 			    MKDEV(PP_MAJOR, port->number), NULL,
809 			    "parport%d", port->number);
810 	if (IS_ERR(ret)) {
811 		pr_err("Failed to create device parport%d\n",
812 		       port->number);
813 		return;
814 	}
815 	devices[port->number] = ret;
816 }
817 
818 static void pp_detach(struct parport *port)
819 {
820 	if (!devices[port->number])
821 		return;
822 
823 	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
824 	devices[port->number] = NULL;
825 }
826 
827 static int pp_probe(struct pardevice *par_dev)
828 {
829 	struct device_driver *drv = par_dev->dev.driver;
830 	int len = strlen(drv->name);
831 
832 	if (strncmp(par_dev->name, drv->name, len))
833 		return -ENODEV;
834 
835 	return 0;
836 }
837 
838 static struct parport_driver pp_driver = {
839 	.name		= CHRDEV,
840 	.probe		= pp_probe,
841 	.match_port	= pp_attach,
842 	.detach		= pp_detach,
843 	.devmodel	= true,
844 };
845 
846 static int __init ppdev_init(void)
847 {
848 	int err = 0;
849 
850 	if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
851 		pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
852 		return -EIO;
853 	}
854 	ppdev_class = class_create(THIS_MODULE, CHRDEV);
855 	if (IS_ERR(ppdev_class)) {
856 		err = PTR_ERR(ppdev_class);
857 		goto out_chrdev;
858 	}
859 	err = parport_register_driver(&pp_driver);
860 	if (err < 0) {
861 		pr_warn(CHRDEV ": unable to register with parport\n");
862 		goto out_class;
863 	}
864 
865 	pr_info(PP_VERSION "\n");
866 	goto out;
867 
868 out_class:
869 	class_destroy(ppdev_class);
870 out_chrdev:
871 	unregister_chrdev(PP_MAJOR, CHRDEV);
872 out:
873 	return err;
874 }
875 
876 static void __exit ppdev_cleanup(void)
877 {
878 	/* Clean up all parport stuff */
879 	parport_unregister_driver(&pp_driver);
880 	class_destroy(ppdev_class);
881 	unregister_chrdev(PP_MAJOR, CHRDEV);
882 }
883 
884 module_init(ppdev_init);
885 module_exit(ppdev_cleanup);
886 
887 MODULE_LICENSE("GPL");
888 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);
889