xref: /openbmc/linux/net/nfc/core.c (revision 0d456bad)
1 /*
2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
3  *
4  * Authors:
5  *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
6  *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the
20  * Free Software Foundation, Inc.,
21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22  */
23 
24 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
25 
26 #include <linux/init.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/slab.h>
30 #include <linux/nfc.h>
31 
32 #include <net/genetlink.h>
33 
34 #include "nfc.h"
35 
36 #define VERSION "0.1"
37 
38 #define NFC_CHECK_PRES_FREQ_MS	2000
39 
40 int nfc_devlist_generation;
41 DEFINE_MUTEX(nfc_devlist_mutex);
42 
43 /* NFC device ID bitmap */
44 static DEFINE_IDA(nfc_index_ida);
45 
46 /**
47  * nfc_dev_up - turn on the NFC device
48  *
49  * @dev: The nfc device to be turned on
50  *
51  * The device remains up until the nfc_dev_down function is called.
52  */
53 int nfc_dev_up(struct nfc_dev *dev)
54 {
55 	int rc = 0;
56 
57 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
58 
59 	device_lock(&dev->dev);
60 
61 	if (!device_is_registered(&dev->dev)) {
62 		rc = -ENODEV;
63 		goto error;
64 	}
65 
66 	if (dev->dev_up) {
67 		rc = -EALREADY;
68 		goto error;
69 	}
70 
71 	if (dev->ops->dev_up)
72 		rc = dev->ops->dev_up(dev);
73 
74 	if (!rc)
75 		dev->dev_up = true;
76 
77 error:
78 	device_unlock(&dev->dev);
79 	return rc;
80 }
81 
82 /**
83  * nfc_dev_down - turn off the NFC device
84  *
85  * @dev: The nfc device to be turned off
86  */
87 int nfc_dev_down(struct nfc_dev *dev)
88 {
89 	int rc = 0;
90 
91 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
92 
93 	device_lock(&dev->dev);
94 
95 	if (!device_is_registered(&dev->dev)) {
96 		rc = -ENODEV;
97 		goto error;
98 	}
99 
100 	if (!dev->dev_up) {
101 		rc = -EALREADY;
102 		goto error;
103 	}
104 
105 	if (dev->polling || dev->active_target) {
106 		rc = -EBUSY;
107 		goto error;
108 	}
109 
110 	if (dev->ops->dev_down)
111 		dev->ops->dev_down(dev);
112 
113 	dev->dev_up = false;
114 
115 error:
116 	device_unlock(&dev->dev);
117 	return rc;
118 }
119 
120 /**
121  * nfc_start_poll - start polling for nfc targets
122  *
123  * @dev: The nfc device that must start polling
124  * @protocols: bitset of nfc protocols that must be used for polling
125  *
126  * The device remains polling for targets until a target is found or
127  * the nfc_stop_poll function is called.
128  */
129 int nfc_start_poll(struct nfc_dev *dev, u32 im_protocols, u32 tm_protocols)
130 {
131 	int rc;
132 
133 	pr_debug("dev_name %s initiator protocols 0x%x target protocols 0x%x\n",
134 		 dev_name(&dev->dev), im_protocols, tm_protocols);
135 
136 	if (!im_protocols && !tm_protocols)
137 		return -EINVAL;
138 
139 	device_lock(&dev->dev);
140 
141 	if (!device_is_registered(&dev->dev)) {
142 		rc = -ENODEV;
143 		goto error;
144 	}
145 
146 	if (dev->polling) {
147 		rc = -EBUSY;
148 		goto error;
149 	}
150 
151 	rc = dev->ops->start_poll(dev, im_protocols, tm_protocols);
152 	if (!rc) {
153 		dev->polling = true;
154 		dev->rf_mode = NFC_RF_NONE;
155 	}
156 
157 error:
158 	device_unlock(&dev->dev);
159 	return rc;
160 }
161 
162 /**
163  * nfc_stop_poll - stop polling for nfc targets
164  *
165  * @dev: The nfc device that must stop polling
166  */
167 int nfc_stop_poll(struct nfc_dev *dev)
168 {
169 	int rc = 0;
170 
171 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
172 
173 	device_lock(&dev->dev);
174 
175 	if (!device_is_registered(&dev->dev)) {
176 		rc = -ENODEV;
177 		goto error;
178 	}
179 
180 	if (!dev->polling) {
181 		rc = -EINVAL;
182 		goto error;
183 	}
184 
185 	dev->ops->stop_poll(dev);
186 	dev->polling = false;
187 	dev->rf_mode = NFC_RF_NONE;
188 
189 error:
190 	device_unlock(&dev->dev);
191 	return rc;
192 }
193 
194 static struct nfc_target *nfc_find_target(struct nfc_dev *dev, u32 target_idx)
195 {
196 	int i;
197 
198 	if (dev->n_targets == 0)
199 		return NULL;
200 
201 	for (i = 0; i < dev->n_targets; i++) {
202 		if (dev->targets[i].idx == target_idx)
203 			return &dev->targets[i];
204 	}
205 
206 	return NULL;
207 }
208 
209 int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)
210 {
211 	int rc = 0;
212 	u8 *gb;
213 	size_t gb_len;
214 	struct nfc_target *target;
215 
216 	pr_debug("dev_name=%s comm %d\n", dev_name(&dev->dev), comm_mode);
217 
218 	if (!dev->ops->dep_link_up)
219 		return -EOPNOTSUPP;
220 
221 	device_lock(&dev->dev);
222 
223 	if (!device_is_registered(&dev->dev)) {
224 		rc = -ENODEV;
225 		goto error;
226 	}
227 
228 	if (dev->dep_link_up == true) {
229 		rc = -EALREADY;
230 		goto error;
231 	}
232 
233 	gb = nfc_llcp_general_bytes(dev, &gb_len);
234 	if (gb_len > NFC_MAX_GT_LEN) {
235 		rc = -EINVAL;
236 		goto error;
237 	}
238 
239 	target = nfc_find_target(dev, target_index);
240 	if (target == NULL) {
241 		rc = -ENOTCONN;
242 		goto error;
243 	}
244 
245 	rc = dev->ops->dep_link_up(dev, target, comm_mode, gb, gb_len);
246 	if (!rc) {
247 		dev->active_target = target;
248 		dev->rf_mode = NFC_RF_INITIATOR;
249 	}
250 
251 error:
252 	device_unlock(&dev->dev);
253 	return rc;
254 }
255 
256 int nfc_dep_link_down(struct nfc_dev *dev)
257 {
258 	int rc = 0;
259 
260 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
261 
262 	if (!dev->ops->dep_link_down)
263 		return -EOPNOTSUPP;
264 
265 	device_lock(&dev->dev);
266 
267 	if (!device_is_registered(&dev->dev)) {
268 		rc = -ENODEV;
269 		goto error;
270 	}
271 
272 	if (dev->dep_link_up == false) {
273 		rc = -EALREADY;
274 		goto error;
275 	}
276 
277 	rc = dev->ops->dep_link_down(dev);
278 	if (!rc) {
279 		dev->dep_link_up = false;
280 		dev->active_target = NULL;
281 		dev->rf_mode = NFC_RF_NONE;
282 		nfc_llcp_mac_is_down(dev);
283 		nfc_genl_dep_link_down_event(dev);
284 	}
285 
286 error:
287 	device_unlock(&dev->dev);
288 
289 	return rc;
290 }
291 
292 int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
293 		       u8 comm_mode, u8 rf_mode)
294 {
295 	dev->dep_link_up = true;
296 
297 	nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);
298 
299 	return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
300 }
301 EXPORT_SYMBOL(nfc_dep_link_is_up);
302 
303 /**
304  * nfc_activate_target - prepare the target for data exchange
305  *
306  * @dev: The nfc device that found the target
307  * @target_idx: index of the target that must be activated
308  * @protocol: nfc protocol that will be used for data exchange
309  */
310 int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
311 {
312 	int rc;
313 	struct nfc_target *target;
314 
315 	pr_debug("dev_name=%s target_idx=%u protocol=%u\n",
316 		 dev_name(&dev->dev), target_idx, protocol);
317 
318 	device_lock(&dev->dev);
319 
320 	if (!device_is_registered(&dev->dev)) {
321 		rc = -ENODEV;
322 		goto error;
323 	}
324 
325 	if (dev->active_target) {
326 		rc = -EBUSY;
327 		goto error;
328 	}
329 
330 	target = nfc_find_target(dev, target_idx);
331 	if (target == NULL) {
332 		rc = -ENOTCONN;
333 		goto error;
334 	}
335 
336 	rc = dev->ops->activate_target(dev, target, protocol);
337 	if (!rc) {
338 		dev->active_target = target;
339 		dev->rf_mode = NFC_RF_INITIATOR;
340 
341 		if (dev->ops->check_presence)
342 			mod_timer(&dev->check_pres_timer, jiffies +
343 				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
344 	}
345 
346 error:
347 	device_unlock(&dev->dev);
348 	return rc;
349 }
350 
351 /**
352  * nfc_deactivate_target - deactivate a nfc target
353  *
354  * @dev: The nfc device that found the target
355  * @target_idx: index of the target that must be deactivated
356  */
357 int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
358 {
359 	int rc = 0;
360 
361 	pr_debug("dev_name=%s target_idx=%u\n",
362 		 dev_name(&dev->dev), target_idx);
363 
364 	device_lock(&dev->dev);
365 
366 	if (!device_is_registered(&dev->dev)) {
367 		rc = -ENODEV;
368 		goto error;
369 	}
370 
371 	if (dev->active_target == NULL) {
372 		rc = -ENOTCONN;
373 		goto error;
374 	}
375 
376 	if (dev->active_target->idx != target_idx) {
377 		rc = -ENOTCONN;
378 		goto error;
379 	}
380 
381 	if (dev->ops->check_presence)
382 		del_timer_sync(&dev->check_pres_timer);
383 
384 	dev->ops->deactivate_target(dev, dev->active_target);
385 	dev->active_target = NULL;
386 
387 error:
388 	device_unlock(&dev->dev);
389 	return rc;
390 }
391 
392 /**
393  * nfc_data_exchange - transceive data
394  *
395  * @dev: The nfc device that found the target
396  * @target_idx: index of the target
397  * @skb: data to be sent
398  * @cb: callback called when the response is received
399  * @cb_context: parameter for the callback function
400  *
401  * The user must wait for the callback before calling this function again.
402  */
403 int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
404 		      data_exchange_cb_t cb, void *cb_context)
405 {
406 	int rc;
407 
408 	pr_debug("dev_name=%s target_idx=%u skb->len=%u\n",
409 		 dev_name(&dev->dev), target_idx, skb->len);
410 
411 	device_lock(&dev->dev);
412 
413 	if (!device_is_registered(&dev->dev)) {
414 		rc = -ENODEV;
415 		kfree_skb(skb);
416 		goto error;
417 	}
418 
419 	if (dev->rf_mode == NFC_RF_INITIATOR && dev->active_target != NULL) {
420 		if (dev->active_target->idx != target_idx) {
421 			rc = -EADDRNOTAVAIL;
422 			kfree_skb(skb);
423 			goto error;
424 		}
425 
426 		if (dev->ops->check_presence)
427 			del_timer_sync(&dev->check_pres_timer);
428 
429 		rc = dev->ops->im_transceive(dev, dev->active_target, skb, cb,
430 					     cb_context);
431 
432 		if (!rc && dev->ops->check_presence)
433 			mod_timer(&dev->check_pres_timer, jiffies +
434 				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
435 	} else if (dev->rf_mode == NFC_RF_TARGET && dev->ops->tm_send != NULL) {
436 		rc = dev->ops->tm_send(dev, skb);
437 	} else {
438 		rc = -ENOTCONN;
439 		kfree_skb(skb);
440 		goto error;
441 	}
442 
443 
444 error:
445 	device_unlock(&dev->dev);
446 	return rc;
447 }
448 
449 int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
450 {
451 	pr_debug("dev_name=%s gb_len=%d\n", dev_name(&dev->dev), gb_len);
452 
453 	if (gb_len > NFC_MAX_GT_LEN)
454 		return -EINVAL;
455 
456 	return nfc_llcp_set_remote_gb(dev, gb, gb_len);
457 }
458 EXPORT_SYMBOL(nfc_set_remote_general_bytes);
459 
460 u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len)
461 {
462 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
463 
464 	return nfc_llcp_general_bytes(dev, gb_len);
465 }
466 EXPORT_SYMBOL(nfc_get_local_general_bytes);
467 
468 int nfc_tm_data_received(struct nfc_dev *dev, struct sk_buff *skb)
469 {
470 	/* Only LLCP target mode for now */
471 	if (dev->dep_link_up == false) {
472 		kfree_skb(skb);
473 		return -ENOLINK;
474 	}
475 
476 	return nfc_llcp_data_received(dev, skb);
477 }
478 EXPORT_SYMBOL(nfc_tm_data_received);
479 
480 int nfc_tm_activated(struct nfc_dev *dev, u32 protocol, u8 comm_mode,
481 		     u8 *gb, size_t gb_len)
482 {
483 	int rc;
484 
485 	device_lock(&dev->dev);
486 
487 	dev->polling = false;
488 
489 	if (gb != NULL) {
490 		rc = nfc_set_remote_general_bytes(dev, gb, gb_len);
491 		if (rc < 0)
492 			goto out;
493 	}
494 
495 	dev->rf_mode = NFC_RF_TARGET;
496 
497 	if (protocol == NFC_PROTO_NFC_DEP_MASK)
498 		nfc_dep_link_is_up(dev, 0, comm_mode, NFC_RF_TARGET);
499 
500 	rc = nfc_genl_tm_activated(dev, protocol);
501 
502 out:
503 	device_unlock(&dev->dev);
504 
505 	return rc;
506 }
507 EXPORT_SYMBOL(nfc_tm_activated);
508 
509 int nfc_tm_deactivated(struct nfc_dev *dev)
510 {
511 	dev->dep_link_up = false;
512 	dev->rf_mode = NFC_RF_NONE;
513 
514 	return nfc_genl_tm_deactivated(dev);
515 }
516 EXPORT_SYMBOL(nfc_tm_deactivated);
517 
518 /**
519  * nfc_alloc_send_skb - allocate a skb for data exchange responses
520  *
521  * @size: size to allocate
522  * @gfp: gfp flags
523  */
524 struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,
525 				   unsigned int flags, unsigned int size,
526 				   unsigned int *err)
527 {
528 	struct sk_buff *skb;
529 	unsigned int total_size;
530 
531 	total_size = size +
532 		dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
533 
534 	skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
535 	if (skb)
536 		skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
537 
538 	return skb;
539 }
540 
541 /**
542  * nfc_alloc_recv_skb - allocate a skb for data exchange responses
543  *
544  * @size: size to allocate
545  * @gfp: gfp flags
546  */
547 struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)
548 {
549 	struct sk_buff *skb;
550 	unsigned int total_size;
551 
552 	total_size = size + 1;
553 	skb = alloc_skb(total_size, gfp);
554 
555 	if (skb)
556 		skb_reserve(skb, 1);
557 
558 	return skb;
559 }
560 EXPORT_SYMBOL(nfc_alloc_recv_skb);
561 
562 /**
563  * nfc_targets_found - inform that targets were found
564  *
565  * @dev: The nfc device that found the targets
566  * @targets: array of nfc targets found
567  * @ntargets: targets array size
568  *
569  * The device driver must call this function when one or many nfc targets
570  * are found. After calling this function, the device driver must stop
571  * polling for targets.
572  * NOTE: This function can be called with targets=NULL and n_targets=0 to
573  * notify a driver error, meaning that the polling operation cannot complete.
574  * IMPORTANT: this function must not be called from an atomic context.
575  * In addition, it must also not be called from a context that would prevent
576  * the NFC Core to call other nfc ops entry point concurrently.
577  */
578 int nfc_targets_found(struct nfc_dev *dev,
579 		      struct nfc_target *targets, int n_targets)
580 {
581 	int i;
582 
583 	pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
584 
585 	for (i = 0; i < n_targets; i++)
586 		targets[i].idx = dev->target_next_idx++;
587 
588 	device_lock(&dev->dev);
589 
590 	if (dev->polling == false) {
591 		device_unlock(&dev->dev);
592 		return 0;
593 	}
594 
595 	dev->polling = false;
596 
597 	dev->targets_generation++;
598 
599 	kfree(dev->targets);
600 	dev->targets = NULL;
601 
602 	if (targets) {
603 		dev->targets = kmemdup(targets,
604 				       n_targets * sizeof(struct nfc_target),
605 				       GFP_ATOMIC);
606 
607 		if (!dev->targets) {
608 			dev->n_targets = 0;
609 			device_unlock(&dev->dev);
610 			return -ENOMEM;
611 		}
612 	}
613 
614 	dev->n_targets = n_targets;
615 	device_unlock(&dev->dev);
616 
617 	nfc_genl_targets_found(dev);
618 
619 	return 0;
620 }
621 EXPORT_SYMBOL(nfc_targets_found);
622 
623 /**
624  * nfc_target_lost - inform that an activated target went out of field
625  *
626  * @dev: The nfc device that had the activated target in field
627  * @target_idx: the nfc index of the target
628  *
629  * The device driver must call this function when the activated target
630  * goes out of the field.
631  * IMPORTANT: this function must not be called from an atomic context.
632  * In addition, it must also not be called from a context that would prevent
633  * the NFC Core to call other nfc ops entry point concurrently.
634  */
635 int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)
636 {
637 	struct nfc_target *tg;
638 	int i;
639 
640 	pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);
641 
642 	device_lock(&dev->dev);
643 
644 	for (i = 0; i < dev->n_targets; i++) {
645 		tg = &dev->targets[i];
646 		if (tg->idx == target_idx)
647 			break;
648 	}
649 
650 	if (i == dev->n_targets) {
651 		device_unlock(&dev->dev);
652 		return -EINVAL;
653 	}
654 
655 	dev->targets_generation++;
656 	dev->n_targets--;
657 	dev->active_target = NULL;
658 
659 	if (dev->n_targets) {
660 		memcpy(&dev->targets[i], &dev->targets[i + 1],
661 		       (dev->n_targets - i) * sizeof(struct nfc_target));
662 	} else {
663 		kfree(dev->targets);
664 		dev->targets = NULL;
665 	}
666 
667 	device_unlock(&dev->dev);
668 
669 	nfc_genl_target_lost(dev, target_idx);
670 
671 	return 0;
672 }
673 EXPORT_SYMBOL(nfc_target_lost);
674 
675 inline void nfc_driver_failure(struct nfc_dev *dev, int err)
676 {
677 	nfc_targets_found(dev, NULL, 0);
678 }
679 EXPORT_SYMBOL(nfc_driver_failure);
680 
681 static void nfc_release(struct device *d)
682 {
683 	struct nfc_dev *dev = to_nfc_dev(d);
684 
685 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
686 
687 	if (dev->ops->check_presence) {
688 		del_timer_sync(&dev->check_pres_timer);
689 		cancel_work_sync(&dev->check_pres_work);
690 	}
691 
692 	nfc_genl_data_exit(&dev->genl_data);
693 	kfree(dev->targets);
694 	kfree(dev);
695 }
696 
697 static void nfc_check_pres_work(struct work_struct *work)
698 {
699 	struct nfc_dev *dev = container_of(work, struct nfc_dev,
700 					   check_pres_work);
701 	int rc;
702 
703 	device_lock(&dev->dev);
704 
705 	if (dev->active_target && timer_pending(&dev->check_pres_timer) == 0) {
706 		rc = dev->ops->check_presence(dev, dev->active_target);
707 		if (rc == -EOPNOTSUPP)
708 			goto exit;
709 		if (!rc) {
710 			mod_timer(&dev->check_pres_timer, jiffies +
711 				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
712 		} else {
713 			u32 active_target_idx = dev->active_target->idx;
714 			device_unlock(&dev->dev);
715 			nfc_target_lost(dev, active_target_idx);
716 			return;
717 		}
718 	}
719 
720 exit:
721 	device_unlock(&dev->dev);
722 }
723 
724 static void nfc_check_pres_timeout(unsigned long data)
725 {
726 	struct nfc_dev *dev = (struct nfc_dev *)data;
727 
728 	schedule_work(&dev->check_pres_work);
729 }
730 
731 struct class nfc_class = {
732 	.name = "nfc",
733 	.dev_release = nfc_release,
734 };
735 EXPORT_SYMBOL(nfc_class);
736 
737 static int match_idx(struct device *d, void *data)
738 {
739 	struct nfc_dev *dev = to_nfc_dev(d);
740 	unsigned int *idx = data;
741 
742 	return dev->idx == *idx;
743 }
744 
745 struct nfc_dev *nfc_get_device(unsigned int idx)
746 {
747 	struct device *d;
748 
749 	d = class_find_device(&nfc_class, NULL, &idx, match_idx);
750 	if (!d)
751 		return NULL;
752 
753 	return to_nfc_dev(d);
754 }
755 
756 /**
757  * nfc_allocate_device - allocate a new nfc device
758  *
759  * @ops: device operations
760  * @supported_protocols: NFC protocols supported by the device
761  */
762 struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
763 				    u32 supported_protocols,
764 				    int tx_headroom, int tx_tailroom)
765 {
766 	struct nfc_dev *dev;
767 
768 	if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
769 	    !ops->deactivate_target || !ops->im_transceive)
770 		return NULL;
771 
772 	if (!supported_protocols)
773 		return NULL;
774 
775 	dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
776 	if (!dev)
777 		return NULL;
778 
779 	dev->ops = ops;
780 	dev->supported_protocols = supported_protocols;
781 	dev->tx_headroom = tx_headroom;
782 	dev->tx_tailroom = tx_tailroom;
783 
784 	nfc_genl_data_init(&dev->genl_data);
785 
786 	dev->rf_mode = NFC_RF_NONE;
787 
788 	/* first generation must not be 0 */
789 	dev->targets_generation = 1;
790 
791 	if (ops->check_presence) {
792 		init_timer(&dev->check_pres_timer);
793 		dev->check_pres_timer.data = (unsigned long)dev;
794 		dev->check_pres_timer.function = nfc_check_pres_timeout;
795 
796 		INIT_WORK(&dev->check_pres_work, nfc_check_pres_work);
797 	}
798 
799 	return dev;
800 }
801 EXPORT_SYMBOL(nfc_allocate_device);
802 
803 /**
804  * nfc_register_device - register a nfc device in the nfc subsystem
805  *
806  * @dev: The nfc device to register
807  */
808 int nfc_register_device(struct nfc_dev *dev)
809 {
810 	int rc;
811 
812 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
813 
814 	dev->idx = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL);
815 	if (dev->idx < 0)
816 		return dev->idx;
817 
818 	dev->dev.class = &nfc_class;
819 	dev_set_name(&dev->dev, "nfc%d", dev->idx);
820 	device_initialize(&dev->dev);
821 
822 	mutex_lock(&nfc_devlist_mutex);
823 	nfc_devlist_generation++;
824 	rc = device_add(&dev->dev);
825 	mutex_unlock(&nfc_devlist_mutex);
826 
827 	if (rc < 0)
828 		return rc;
829 
830 	rc = nfc_llcp_register_device(dev);
831 	if (rc)
832 		pr_err("Could not register llcp device\n");
833 
834 	rc = nfc_genl_device_added(dev);
835 	if (rc)
836 		pr_debug("The userspace won't be notified that the device %s was added\n",
837 			 dev_name(&dev->dev));
838 
839 	return 0;
840 }
841 EXPORT_SYMBOL(nfc_register_device);
842 
843 /**
844  * nfc_unregister_device - unregister a nfc device in the nfc subsystem
845  *
846  * @dev: The nfc device to unregister
847  */
848 void nfc_unregister_device(struct nfc_dev *dev)
849 {
850 	int rc, id;
851 
852 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
853 
854 	id = dev->idx;
855 
856 	mutex_lock(&nfc_devlist_mutex);
857 	nfc_devlist_generation++;
858 
859 	/* lock to avoid unregistering a device while an operation
860 	   is in progress */
861 	device_lock(&dev->dev);
862 	device_del(&dev->dev);
863 	device_unlock(&dev->dev);
864 
865 	mutex_unlock(&nfc_devlist_mutex);
866 
867 	nfc_llcp_unregister_device(dev);
868 
869 	rc = nfc_genl_device_removed(dev);
870 	if (rc)
871 		pr_debug("The userspace won't be notified that the device %s was removed\n",
872 			 dev_name(&dev->dev));
873 
874 	ida_simple_remove(&nfc_index_ida, id);
875 
876 }
877 EXPORT_SYMBOL(nfc_unregister_device);
878 
879 static int __init nfc_init(void)
880 {
881 	int rc;
882 
883 	pr_info("NFC Core ver %s\n", VERSION);
884 
885 	rc = class_register(&nfc_class);
886 	if (rc)
887 		return rc;
888 
889 	rc = nfc_genl_init();
890 	if (rc)
891 		goto err_genl;
892 
893 	/* the first generation must not be 0 */
894 	nfc_devlist_generation = 1;
895 
896 	rc = rawsock_init();
897 	if (rc)
898 		goto err_rawsock;
899 
900 	rc = nfc_llcp_init();
901 	if (rc)
902 		goto err_llcp_sock;
903 
904 	rc = af_nfc_init();
905 	if (rc)
906 		goto err_af_nfc;
907 
908 	return 0;
909 
910 err_af_nfc:
911 	nfc_llcp_exit();
912 err_llcp_sock:
913 	rawsock_exit();
914 err_rawsock:
915 	nfc_genl_exit();
916 err_genl:
917 	class_unregister(&nfc_class);
918 	return rc;
919 }
920 
921 static void __exit nfc_exit(void)
922 {
923 	af_nfc_exit();
924 	nfc_llcp_exit();
925 	rawsock_exit();
926 	nfc_genl_exit();
927 	class_unregister(&nfc_class);
928 }
929 
930 subsys_initcall(nfc_init);
931 module_exit(nfc_exit);
932 
933 MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>");
934 MODULE_DESCRIPTION("NFC Core ver " VERSION);
935 MODULE_VERSION(VERSION);
936 MODULE_LICENSE("GPL");
937 MODULE_ALIAS_NETPROTO(PF_NFC);
938 MODULE_ALIAS_GENL_FAMILY(NFC_GENL_NAME);
939