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 
pp_enable_irq(struct pp_struct * pp)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 
pp_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)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 
pp_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)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 
pp_irq(void * private)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 
register_device(int minor,struct pp_struct * pp)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_free_name;
300 	}
301 
302 	index = ida_alloc(&ida_index, GFP_KERNEL);
303 	if (index < 0) {
304 		pr_warn("%s: failed to get index!\n", name);
305 		rc = index;
306 		goto err_put_port;
307 	}
308 
309 	memset(&ppdev_cb, 0, sizeof(ppdev_cb));
310 	ppdev_cb.irq_func = pp_irq;
311 	ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
312 	ppdev_cb.private = pp;
313 	pdev = parport_register_dev_model(port, name, &ppdev_cb, index);
314 
315 	if (!pdev) {
316 		pr_warn("%s: failed to register device!\n", name);
317 		rc = -ENXIO;
318 		ida_free(&ida_index, index);
319 		goto err_put_port;
320 	}
321 
322 	pp->pdev = pdev;
323 	pp->index = index;
324 	dev_dbg(&pdev->dev, "registered pardevice\n");
325 err_put_port:
326 	parport_put_port(port);
327 err_free_name:
328 	kfree(name);
329 	return rc;
330 }
331 
init_phase(int mode)332 static enum ieee1284_phase init_phase(int mode)
333 {
334 	switch (mode & ~(IEEE1284_DEVICEID
335 			 | IEEE1284_ADDR)) {
336 	case IEEE1284_MODE_NIBBLE:
337 	case IEEE1284_MODE_BYTE:
338 		return IEEE1284_PH_REV_IDLE;
339 	}
340 	return IEEE1284_PH_FWD_IDLE;
341 }
342 
pp_set_timeout(struct pardevice * pdev,long tv_sec,int tv_usec)343 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
344 {
345 	long to_jiffies;
346 
347 	if ((tv_sec < 0) || (tv_usec < 0))
348 		return -EINVAL;
349 
350 	to_jiffies = usecs_to_jiffies(tv_usec);
351 	to_jiffies += tv_sec * HZ;
352 	if (to_jiffies <= 0)
353 		return -EINVAL;
354 
355 	pdev->timeout = to_jiffies;
356 	return 0;
357 }
358 
pp_do_ioctl(struct file * file,unsigned int cmd,unsigned long arg)359 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
360 {
361 	unsigned int minor = iminor(file_inode(file));
362 	struct pp_struct *pp = file->private_data;
363 	struct parport *port;
364 	void __user *argp = (void __user *)arg;
365 	struct ieee1284_info *info;
366 	unsigned char reg;
367 	unsigned char mask;
368 	int mode;
369 	s32 time32[2];
370 	s64 time64[2];
371 	struct timespec64 ts;
372 	int ret;
373 
374 	/* First handle the cases that don't take arguments. */
375 	switch (cmd) {
376 	case PPCLAIM:
377 	    {
378 		if (pp->flags & PP_CLAIMED) {
379 			dev_dbg(&pp->pdev->dev, "you've already got it!\n");
380 			return -EINVAL;
381 		}
382 
383 		/* Deferred device registration. */
384 		if (!pp->pdev) {
385 			int err = register_device(minor, pp);
386 
387 			if (err)
388 				return err;
389 		}
390 
391 		ret = parport_claim_or_block(pp->pdev);
392 		if (ret < 0)
393 			return ret;
394 
395 		pp->flags |= PP_CLAIMED;
396 
397 		/* For interrupt-reporting to work, we need to be
398 		 * informed of each interrupt. */
399 		pp_enable_irq(pp);
400 
401 		/* We may need to fix up the state machine. */
402 		info = &pp->pdev->port->ieee1284;
403 		pp->saved_state.mode = info->mode;
404 		pp->saved_state.phase = info->phase;
405 		info->mode = pp->state.mode;
406 		info->phase = pp->state.phase;
407 		pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
408 		parport_set_timeout(pp->pdev, pp->default_inactivity);
409 
410 		return 0;
411 	    }
412 	case PPEXCL:
413 		if (pp->pdev) {
414 			dev_dbg(&pp->pdev->dev,
415 				"too late for PPEXCL; already registered\n");
416 			if (pp->flags & PP_EXCL)
417 				/* But it's not really an error. */
418 				return 0;
419 			/* There's no chance of making the driver happy. */
420 			return -EINVAL;
421 		}
422 
423 		/* Just remember to register the device exclusively
424 		 * when we finally do the registration. */
425 		pp->flags |= PP_EXCL;
426 		return 0;
427 	case PPSETMODE:
428 	    {
429 		int mode;
430 
431 		if (copy_from_user(&mode, argp, sizeof(mode)))
432 			return -EFAULT;
433 		/* FIXME: validate mode */
434 		pp->state.mode = mode;
435 		pp->state.phase = init_phase(mode);
436 
437 		if (pp->flags & PP_CLAIMED) {
438 			pp->pdev->port->ieee1284.mode = mode;
439 			pp->pdev->port->ieee1284.phase = pp->state.phase;
440 		}
441 
442 		return 0;
443 	    }
444 	case PPGETMODE:
445 	    {
446 		int mode;
447 
448 		if (pp->flags & PP_CLAIMED)
449 			mode = pp->pdev->port->ieee1284.mode;
450 		else
451 			mode = pp->state.mode;
452 
453 		if (copy_to_user(argp, &mode, sizeof(mode)))
454 			return -EFAULT;
455 		return 0;
456 	    }
457 	case PPSETPHASE:
458 	    {
459 		int phase;
460 
461 		if (copy_from_user(&phase, argp, sizeof(phase)))
462 			return -EFAULT;
463 
464 		/* FIXME: validate phase */
465 		pp->state.phase = phase;
466 
467 		if (pp->flags & PP_CLAIMED)
468 			pp->pdev->port->ieee1284.phase = phase;
469 
470 		return 0;
471 	    }
472 	case PPGETPHASE:
473 	    {
474 		int phase;
475 
476 		if (pp->flags & PP_CLAIMED)
477 			phase = pp->pdev->port->ieee1284.phase;
478 		else
479 			phase = pp->state.phase;
480 		if (copy_to_user(argp, &phase, sizeof(phase)))
481 			return -EFAULT;
482 		return 0;
483 	    }
484 	case PPGETMODES:
485 	    {
486 		unsigned int modes;
487 
488 		port = parport_find_number(minor);
489 		if (!port)
490 			return -ENODEV;
491 
492 		modes = port->modes;
493 		parport_put_port(port);
494 		if (copy_to_user(argp, &modes, sizeof(modes)))
495 			return -EFAULT;
496 		return 0;
497 	    }
498 	case PPSETFLAGS:
499 	    {
500 		int uflags;
501 
502 		if (copy_from_user(&uflags, argp, sizeof(uflags)))
503 			return -EFAULT;
504 		pp->flags &= ~PP_FLAGMASK;
505 		pp->flags |= (uflags & PP_FLAGMASK);
506 		return 0;
507 	    }
508 	case PPGETFLAGS:
509 	    {
510 		int uflags;
511 
512 		uflags = pp->flags & PP_FLAGMASK;
513 		if (copy_to_user(argp, &uflags, sizeof(uflags)))
514 			return -EFAULT;
515 		return 0;
516 	    }
517 	}	/* end switch() */
518 
519 	/* Everything else requires the port to be claimed, so check
520 	 * that now. */
521 	if ((pp->flags & PP_CLAIMED) == 0) {
522 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
523 		return -EINVAL;
524 	}
525 
526 	port = pp->pdev->port;
527 	switch (cmd) {
528 	case PPRSTATUS:
529 		reg = parport_read_status(port);
530 		if (copy_to_user(argp, &reg, sizeof(reg)))
531 			return -EFAULT;
532 		return 0;
533 	case PPRDATA:
534 		reg = parport_read_data(port);
535 		if (copy_to_user(argp, &reg, sizeof(reg)))
536 			return -EFAULT;
537 		return 0;
538 	case PPRCONTROL:
539 		reg = parport_read_control(port);
540 		if (copy_to_user(argp, &reg, sizeof(reg)))
541 			return -EFAULT;
542 		return 0;
543 	case PPYIELD:
544 		parport_yield_blocking(pp->pdev);
545 		return 0;
546 
547 	case PPRELEASE:
548 		/* Save the state machine's state. */
549 		info = &pp->pdev->port->ieee1284;
550 		pp->state.mode = info->mode;
551 		pp->state.phase = info->phase;
552 		info->mode = pp->saved_state.mode;
553 		info->phase = pp->saved_state.phase;
554 		parport_release(pp->pdev);
555 		pp->flags &= ~PP_CLAIMED;
556 		return 0;
557 
558 	case PPWCONTROL:
559 		if (copy_from_user(&reg, argp, sizeof(reg)))
560 			return -EFAULT;
561 		parport_write_control(port, reg);
562 		return 0;
563 
564 	case PPWDATA:
565 		if (copy_from_user(&reg, argp, sizeof(reg)))
566 			return -EFAULT;
567 		parport_write_data(port, reg);
568 		return 0;
569 
570 	case PPFCONTROL:
571 		if (copy_from_user(&mask, argp,
572 				   sizeof(mask)))
573 			return -EFAULT;
574 		if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
575 				   sizeof(reg)))
576 			return -EFAULT;
577 		parport_frob_control(port, mask, reg);
578 		return 0;
579 
580 	case PPDATADIR:
581 		if (copy_from_user(&mode, argp, sizeof(mode)))
582 			return -EFAULT;
583 		if (mode)
584 			port->ops->data_reverse(port);
585 		else
586 			port->ops->data_forward(port);
587 		return 0;
588 
589 	case PPNEGOT:
590 		if (copy_from_user(&mode, argp, sizeof(mode)))
591 			return -EFAULT;
592 		switch ((ret = parport_negotiate(port, mode))) {
593 		case 0: break;
594 		case -1: /* handshake failed, peripheral not IEEE 1284 */
595 			ret = -EIO;
596 			break;
597 		case 1:  /* handshake succeeded, peripheral rejected mode */
598 			ret = -ENXIO;
599 			break;
600 		}
601 		pp_enable_irq(pp);
602 		return ret;
603 
604 	case PPWCTLONIRQ:
605 		if (copy_from_user(&reg, argp, sizeof(reg)))
606 			return -EFAULT;
607 
608 		/* Remember what to set the control lines to, for next
609 		 * time we get an interrupt. */
610 		pp->irqctl = reg;
611 		pp->irqresponse = 1;
612 		return 0;
613 
614 	case PPCLRIRQ:
615 		ret = atomic_read(&pp->irqc);
616 		if (copy_to_user(argp, &ret, sizeof(ret)))
617 			return -EFAULT;
618 		atomic_sub(ret, &pp->irqc);
619 		return 0;
620 
621 	case PPSETTIME32:
622 		if (copy_from_user(time32, argp, sizeof(time32)))
623 			return -EFAULT;
624 
625 		if ((time32[0] < 0) || (time32[1] < 0))
626 			return -EINVAL;
627 
628 		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
629 
630 	case PPSETTIME64:
631 		if (copy_from_user(time64, argp, sizeof(time64)))
632 			return -EFAULT;
633 
634 		if ((time64[0] < 0) || (time64[1] < 0))
635 			return -EINVAL;
636 
637 		if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
638 			time64[1] >>= 32;
639 
640 		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
641 
642 	case PPGETTIME32:
643 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
644 		time32[0] = ts.tv_sec;
645 		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
646 
647 		if (copy_to_user(argp, time32, sizeof(time32)))
648 			return -EFAULT;
649 
650 		return 0;
651 
652 	case PPGETTIME64:
653 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
654 		time64[0] = ts.tv_sec;
655 		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
656 
657 		if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
658 			time64[1] <<= 32;
659 
660 		if (copy_to_user(argp, time64, sizeof(time64)))
661 			return -EFAULT;
662 
663 		return 0;
664 
665 	default:
666 		dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
667 		return -EINVAL;
668 	}
669 
670 	/* Keep the compiler happy */
671 	return 0;
672 }
673 
pp_ioctl(struct file * file,unsigned int cmd,unsigned long arg)674 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
675 {
676 	long ret;
677 
678 	mutex_lock(&pp_do_mutex);
679 	ret = pp_do_ioctl(file, cmd, arg);
680 	mutex_unlock(&pp_do_mutex);
681 	return ret;
682 }
683 
pp_open(struct inode * inode,struct file * file)684 static int pp_open(struct inode *inode, struct file *file)
685 {
686 	unsigned int minor = iminor(inode);
687 	struct pp_struct *pp;
688 
689 	if (minor >= PARPORT_MAX)
690 		return -ENXIO;
691 
692 	pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
693 	if (!pp)
694 		return -ENOMEM;
695 
696 	pp->state.mode = IEEE1284_MODE_COMPAT;
697 	pp->state.phase = init_phase(pp->state.mode);
698 	pp->flags = 0;
699 	pp->irqresponse = 0;
700 	atomic_set(&pp->irqc, 0);
701 	init_waitqueue_head(&pp->irq_wait);
702 
703 	/* Defer the actual device registration until the first claim.
704 	 * That way, we know whether or not the driver wants to have
705 	 * exclusive access to the port (PPEXCL).
706 	 */
707 	pp->pdev = NULL;
708 	file->private_data = pp;
709 
710 	return 0;
711 }
712 
pp_release(struct inode * inode,struct file * file)713 static int pp_release(struct inode *inode, struct file *file)
714 {
715 	unsigned int minor = iminor(inode);
716 	struct pp_struct *pp = file->private_data;
717 	int compat_negot;
718 
719 	compat_negot = 0;
720 	if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
721 	    (pp->state.mode != IEEE1284_MODE_COMPAT)) {
722 		struct ieee1284_info *info;
723 
724 		/* parport released, but not in compatibility mode */
725 		parport_claim_or_block(pp->pdev);
726 		pp->flags |= PP_CLAIMED;
727 		info = &pp->pdev->port->ieee1284;
728 		pp->saved_state.mode = info->mode;
729 		pp->saved_state.phase = info->phase;
730 		info->mode = pp->state.mode;
731 		info->phase = pp->state.phase;
732 		compat_negot = 1;
733 	} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
734 	    (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
735 		compat_negot = 2;
736 	}
737 	if (compat_negot) {
738 		parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
739 		dev_dbg(&pp->pdev->dev,
740 			"negotiated back to compatibility mode because user-space forgot\n");
741 	}
742 
743 	if ((pp->flags & PP_CLAIMED) && pp->pdev) {
744 		struct ieee1284_info *info;
745 
746 		info = &pp->pdev->port->ieee1284;
747 		pp->state.mode = info->mode;
748 		pp->state.phase = info->phase;
749 		info->mode = pp->saved_state.mode;
750 		info->phase = pp->saved_state.phase;
751 		parport_release(pp->pdev);
752 		if (compat_negot != 1) {
753 			pr_debug(CHRDEV "%x: released pardevice "
754 				"because user-space forgot\n", minor);
755 		}
756 	}
757 
758 	if (pp->pdev) {
759 		parport_unregister_device(pp->pdev);
760 		ida_free(&ida_index, pp->index);
761 		pp->pdev = NULL;
762 		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
763 	}
764 
765 	kfree(pp);
766 
767 	return 0;
768 }
769 
770 /* No kernel lock held - fine */
pp_poll(struct file * file,poll_table * wait)771 static __poll_t pp_poll(struct file *file, poll_table *wait)
772 {
773 	struct pp_struct *pp = file->private_data;
774 	__poll_t mask = 0;
775 
776 	poll_wait(file, &pp->irq_wait, wait);
777 	if (atomic_read(&pp->irqc))
778 		mask |= EPOLLIN | EPOLLRDNORM;
779 
780 	return mask;
781 }
782 
783 static const struct class ppdev_class = {
784 	.name = CHRDEV,
785 };
786 
787 static const struct file_operations pp_fops = {
788 	.owner		= THIS_MODULE,
789 	.read		= pp_read,
790 	.write		= pp_write,
791 	.poll		= pp_poll,
792 	.unlocked_ioctl	= pp_ioctl,
793 	.compat_ioctl   = compat_ptr_ioctl,
794 	.open		= pp_open,
795 	.release	= pp_release,
796 };
797 
pp_attach(struct parport * port)798 static void pp_attach(struct parport *port)
799 {
800 	struct device *ret;
801 
802 	if (devices[port->number])
803 		return;
804 
805 	ret = device_create(&ppdev_class, port->dev,
806 			    MKDEV(PP_MAJOR, port->number), NULL,
807 			    "parport%d", port->number);
808 	if (IS_ERR(ret)) {
809 		pr_err("Failed to create device parport%d\n",
810 		       port->number);
811 		return;
812 	}
813 	devices[port->number] = ret;
814 }
815 
pp_detach(struct parport * port)816 static void pp_detach(struct parport *port)
817 {
818 	if (!devices[port->number])
819 		return;
820 
821 	device_destroy(&ppdev_class, MKDEV(PP_MAJOR, port->number));
822 	devices[port->number] = NULL;
823 }
824 
pp_probe(struct pardevice * par_dev)825 static int pp_probe(struct pardevice *par_dev)
826 {
827 	struct device_driver *drv = par_dev->dev.driver;
828 	int len = strlen(drv->name);
829 
830 	if (strncmp(par_dev->name, drv->name, len))
831 		return -ENODEV;
832 
833 	return 0;
834 }
835 
836 static struct parport_driver pp_driver = {
837 	.name		= CHRDEV,
838 	.probe		= pp_probe,
839 	.match_port	= pp_attach,
840 	.detach		= pp_detach,
841 };
842 
ppdev_init(void)843 static int __init ppdev_init(void)
844 {
845 	int err = 0;
846 
847 	if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
848 		pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
849 		return -EIO;
850 	}
851 	err = class_register(&ppdev_class);
852 	if (err)
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_unregister(&ppdev_class);
866 out_chrdev:
867 	unregister_chrdev(PP_MAJOR, CHRDEV);
868 out:
869 	return err;
870 }
871 
ppdev_cleanup(void)872 static void __exit ppdev_cleanup(void)
873 {
874 	/* Clean up all parport stuff */
875 	parport_unregister_driver(&pp_driver);
876 	class_unregister(&ppdev_class);
877 	unregister_chrdev(PP_MAJOR, CHRDEV);
878 }
879 
880 module_init(ppdev_init);
881 module_exit(ppdev_cleanup);
882 
883 MODULE_DESCRIPTION("Support for user-space parallel port device drivers");
884 MODULE_LICENSE("GPL");
885 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);
886