xref: /openbmc/linux/net/nfc/nci/core.c (revision 64405360)
1 /*
2  *  The NFC Controller Interface is the communication protocol between an
3  *  NFC Controller (NFCC) and a Device Host (DH).
4  *
5  *  Copyright (C) 2011 Texas Instruments, Inc.
6  *
7  *  Written by Ilan Elias <ilane@ti.com>
8  *
9  *  Acknowledgements:
10  *  This file is based on hci_core.c, which was written
11  *  by Maxim Krasnyansky.
12  *
13  *  This program is free software; you can redistribute it and/or modify
14  *  it under the terms of the GNU General Public License version 2
15  *  as published by the Free Software Foundation
16  *
17  *  This program is distributed in the hope that it will be useful,
18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20  *  GNU General Public License for more details.
21  *
22  *  You should have received a copy of the GNU General Public License
23  *  along with this program; if not, write to the Free Software
24  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
25  *
26  */
27 
28 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
29 
30 #include <linux/types.h>
31 #include <linux/workqueue.h>
32 #include <linux/completion.h>
33 #include <linux/export.h>
34 #include <linux/sched.h>
35 #include <linux/bitops.h>
36 #include <linux/skbuff.h>
37 
38 #include "../nfc.h"
39 #include <net/nfc/nci.h>
40 #include <net/nfc/nci_core.h>
41 #include <linux/nfc.h>
42 
43 static void nci_cmd_work(struct work_struct *work);
44 static void nci_rx_work(struct work_struct *work);
45 static void nci_tx_work(struct work_struct *work);
46 
47 /* ---- NCI requests ---- */
48 
49 void nci_req_complete(struct nci_dev *ndev, int result)
50 {
51 	if (ndev->req_status == NCI_REQ_PEND) {
52 		ndev->req_result = result;
53 		ndev->req_status = NCI_REQ_DONE;
54 		complete(&ndev->req_completion);
55 	}
56 }
57 
58 static void nci_req_cancel(struct nci_dev *ndev, int err)
59 {
60 	if (ndev->req_status == NCI_REQ_PEND) {
61 		ndev->req_result = err;
62 		ndev->req_status = NCI_REQ_CANCELED;
63 		complete(&ndev->req_completion);
64 	}
65 }
66 
67 /* Execute request and wait for completion. */
68 static int __nci_request(struct nci_dev *ndev,
69 	void (*req)(struct nci_dev *ndev, unsigned long opt),
70 	unsigned long opt,
71 	__u32 timeout)
72 {
73 	int rc = 0;
74 	long completion_rc;
75 
76 	ndev->req_status = NCI_REQ_PEND;
77 
78 	init_completion(&ndev->req_completion);
79 	req(ndev, opt);
80 	completion_rc = wait_for_completion_interruptible_timeout(
81 							&ndev->req_completion,
82 							timeout);
83 
84 	pr_debug("wait_for_completion return %ld\n", completion_rc);
85 
86 	if (completion_rc > 0) {
87 		switch (ndev->req_status) {
88 		case NCI_REQ_DONE:
89 			rc = nci_to_errno(ndev->req_result);
90 			break;
91 
92 		case NCI_REQ_CANCELED:
93 			rc = -ndev->req_result;
94 			break;
95 
96 		default:
97 			rc = -ETIMEDOUT;
98 			break;
99 		}
100 	} else {
101 		pr_err("wait_for_completion_interruptible_timeout failed %ld\n",
102 		       completion_rc);
103 
104 		rc = ((completion_rc == 0) ? (-ETIMEDOUT) : (completion_rc));
105 	}
106 
107 	ndev->req_status = ndev->req_result = 0;
108 
109 	return rc;
110 }
111 
112 static inline int nci_request(struct nci_dev *ndev,
113 		void (*req)(struct nci_dev *ndev, unsigned long opt),
114 		unsigned long opt, __u32 timeout)
115 {
116 	int rc;
117 
118 	if (!test_bit(NCI_UP, &ndev->flags))
119 		return -ENETDOWN;
120 
121 	/* Serialize all requests */
122 	mutex_lock(&ndev->req_lock);
123 	rc = __nci_request(ndev, req, opt, timeout);
124 	mutex_unlock(&ndev->req_lock);
125 
126 	return rc;
127 }
128 
129 static void nci_reset_req(struct nci_dev *ndev, unsigned long opt)
130 {
131 	struct nci_core_reset_cmd cmd;
132 
133 	cmd.reset_type = NCI_RESET_TYPE_RESET_CONFIG;
134 	nci_send_cmd(ndev, NCI_OP_CORE_RESET_CMD, 1, &cmd);
135 }
136 
137 static void nci_init_req(struct nci_dev *ndev, unsigned long opt)
138 {
139 	nci_send_cmd(ndev, NCI_OP_CORE_INIT_CMD, 0, NULL);
140 }
141 
142 static void nci_init_complete_req(struct nci_dev *ndev, unsigned long opt)
143 {
144 	struct nci_rf_disc_map_cmd cmd;
145 	struct disc_map_config *cfg = cmd.mapping_configs;
146 	__u8 *num = &cmd.num_mapping_configs;
147 	int i;
148 
149 	/* set rf mapping configurations */
150 	*num = 0;
151 
152 	/* by default mapping is set to NCI_RF_INTERFACE_FRAME */
153 	for (i = 0; i < ndev->num_supported_rf_interfaces; i++) {
154 		if (ndev->supported_rf_interfaces[i] ==
155 			NCI_RF_INTERFACE_ISO_DEP) {
156 			cfg[*num].rf_protocol = NCI_RF_PROTOCOL_ISO_DEP;
157 			cfg[*num].mode = NCI_DISC_MAP_MODE_POLL |
158 				NCI_DISC_MAP_MODE_LISTEN;
159 			cfg[*num].rf_interface = NCI_RF_INTERFACE_ISO_DEP;
160 			(*num)++;
161 		} else if (ndev->supported_rf_interfaces[i] ==
162 			NCI_RF_INTERFACE_NFC_DEP) {
163 			cfg[*num].rf_protocol = NCI_RF_PROTOCOL_NFC_DEP;
164 			cfg[*num].mode = NCI_DISC_MAP_MODE_POLL |
165 				NCI_DISC_MAP_MODE_LISTEN;
166 			cfg[*num].rf_interface = NCI_RF_INTERFACE_NFC_DEP;
167 			(*num)++;
168 		}
169 
170 		if (*num == NCI_MAX_NUM_MAPPING_CONFIGS)
171 			break;
172 	}
173 
174 	nci_send_cmd(ndev, NCI_OP_RF_DISCOVER_MAP_CMD,
175 		(1 + ((*num)*sizeof(struct disc_map_config))),
176 		&cmd);
177 }
178 
179 static void nci_rf_discover_req(struct nci_dev *ndev, unsigned long opt)
180 {
181 	struct nci_rf_disc_cmd cmd;
182 	__u32 protocols = opt;
183 
184 	cmd.num_disc_configs = 0;
185 
186 	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
187 		(protocols & NFC_PROTO_JEWEL_MASK
188 		|| protocols & NFC_PROTO_MIFARE_MASK
189 		|| protocols & NFC_PROTO_ISO14443_MASK
190 		|| protocols & NFC_PROTO_NFC_DEP_MASK)) {
191 		cmd.disc_configs[cmd.num_disc_configs].rf_tech_and_mode =
192 		NCI_NFC_A_PASSIVE_POLL_MODE;
193 		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
194 		cmd.num_disc_configs++;
195 	}
196 
197 	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
198 		(protocols & NFC_PROTO_ISO14443_MASK)) {
199 		cmd.disc_configs[cmd.num_disc_configs].rf_tech_and_mode =
200 		NCI_NFC_B_PASSIVE_POLL_MODE;
201 		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
202 		cmd.num_disc_configs++;
203 	}
204 
205 	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
206 		(protocols & NFC_PROTO_FELICA_MASK
207 		|| protocols & NFC_PROTO_NFC_DEP_MASK)) {
208 		cmd.disc_configs[cmd.num_disc_configs].rf_tech_and_mode =
209 		NCI_NFC_F_PASSIVE_POLL_MODE;
210 		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
211 		cmd.num_disc_configs++;
212 	}
213 
214 	nci_send_cmd(ndev, NCI_OP_RF_DISCOVER_CMD,
215 		(1 + (cmd.num_disc_configs*sizeof(struct disc_config))),
216 		&cmd);
217 }
218 
219 static void nci_rf_deactivate_req(struct nci_dev *ndev, unsigned long opt)
220 {
221 	struct nci_rf_deactivate_cmd cmd;
222 
223 	cmd.type = NCI_DEACTIVATE_TYPE_IDLE_MODE;
224 
225 	nci_send_cmd(ndev, NCI_OP_RF_DEACTIVATE_CMD,
226 			sizeof(struct nci_rf_deactivate_cmd),
227 			&cmd);
228 }
229 
230 static int nci_open_device(struct nci_dev *ndev)
231 {
232 	int rc = 0;
233 
234 	mutex_lock(&ndev->req_lock);
235 
236 	if (test_bit(NCI_UP, &ndev->flags)) {
237 		rc = -EALREADY;
238 		goto done;
239 	}
240 
241 	if (ndev->ops->open(ndev)) {
242 		rc = -EIO;
243 		goto done;
244 	}
245 
246 	atomic_set(&ndev->cmd_cnt, 1);
247 
248 	set_bit(NCI_INIT, &ndev->flags);
249 
250 	rc = __nci_request(ndev, nci_reset_req, 0,
251 				msecs_to_jiffies(NCI_RESET_TIMEOUT));
252 
253 	if (!rc) {
254 		rc = __nci_request(ndev, nci_init_req, 0,
255 				msecs_to_jiffies(NCI_INIT_TIMEOUT));
256 	}
257 
258 	if (!rc) {
259 		rc = __nci_request(ndev, nci_init_complete_req, 0,
260 				msecs_to_jiffies(NCI_INIT_TIMEOUT));
261 	}
262 
263 	clear_bit(NCI_INIT, &ndev->flags);
264 
265 	if (!rc) {
266 		set_bit(NCI_UP, &ndev->flags);
267 	} else {
268 		/* Init failed, cleanup */
269 		skb_queue_purge(&ndev->cmd_q);
270 		skb_queue_purge(&ndev->rx_q);
271 		skb_queue_purge(&ndev->tx_q);
272 
273 		ndev->ops->close(ndev);
274 		ndev->flags = 0;
275 	}
276 
277 done:
278 	mutex_unlock(&ndev->req_lock);
279 	return rc;
280 }
281 
282 static int nci_close_device(struct nci_dev *ndev)
283 {
284 	nci_req_cancel(ndev, ENODEV);
285 	mutex_lock(&ndev->req_lock);
286 
287 	if (!test_and_clear_bit(NCI_UP, &ndev->flags)) {
288 		del_timer_sync(&ndev->cmd_timer);
289 		mutex_unlock(&ndev->req_lock);
290 		return 0;
291 	}
292 
293 	/* Drop RX and TX queues */
294 	skb_queue_purge(&ndev->rx_q);
295 	skb_queue_purge(&ndev->tx_q);
296 
297 	/* Flush RX and TX wq */
298 	flush_workqueue(ndev->rx_wq);
299 	flush_workqueue(ndev->tx_wq);
300 
301 	/* Reset device */
302 	skb_queue_purge(&ndev->cmd_q);
303 	atomic_set(&ndev->cmd_cnt, 1);
304 
305 	set_bit(NCI_INIT, &ndev->flags);
306 	__nci_request(ndev, nci_reset_req, 0,
307 				msecs_to_jiffies(NCI_RESET_TIMEOUT));
308 	clear_bit(NCI_INIT, &ndev->flags);
309 
310 	/* Flush cmd wq */
311 	flush_workqueue(ndev->cmd_wq);
312 
313 	/* After this point our queues are empty
314 	 * and no works are scheduled. */
315 	ndev->ops->close(ndev);
316 
317 	/* Clear flags */
318 	ndev->flags = 0;
319 
320 	mutex_unlock(&ndev->req_lock);
321 
322 	return 0;
323 }
324 
325 /* NCI command timer function */
326 static void nci_cmd_timer(unsigned long arg)
327 {
328 	struct nci_dev *ndev = (void *) arg;
329 
330 	atomic_set(&ndev->cmd_cnt, 1);
331 	queue_work(ndev->cmd_wq, &ndev->cmd_work);
332 }
333 
334 static int nci_dev_up(struct nfc_dev *nfc_dev)
335 {
336 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
337 
338 	return nci_open_device(ndev);
339 }
340 
341 static int nci_dev_down(struct nfc_dev *nfc_dev)
342 {
343 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
344 
345 	return nci_close_device(ndev);
346 }
347 
348 static int nci_start_poll(struct nfc_dev *nfc_dev, __u32 protocols)
349 {
350 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
351 	int rc;
352 
353 	if (test_bit(NCI_DISCOVERY, &ndev->flags)) {
354 		pr_err("unable to start poll, since poll is already active\n");
355 		return -EBUSY;
356 	}
357 
358 	if (ndev->target_active_prot) {
359 		pr_err("there is an active target\n");
360 		return -EBUSY;
361 	}
362 
363 	if (test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
364 		pr_debug("target is active, implicitly deactivate...\n");
365 
366 		rc = nci_request(ndev, nci_rf_deactivate_req, 0,
367 			msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
368 		if (rc)
369 			return -EBUSY;
370 	}
371 
372 	rc = nci_request(ndev, nci_rf_discover_req, protocols,
373 		msecs_to_jiffies(NCI_RF_DISC_TIMEOUT));
374 
375 	if (!rc)
376 		ndev->poll_prots = protocols;
377 
378 	return rc;
379 }
380 
381 static void nci_stop_poll(struct nfc_dev *nfc_dev)
382 {
383 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
384 
385 	if (!test_bit(NCI_DISCOVERY, &ndev->flags)) {
386 		pr_err("unable to stop poll, since poll is not active\n");
387 		return;
388 	}
389 
390 	nci_request(ndev, nci_rf_deactivate_req, 0,
391 		msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
392 }
393 
394 static int nci_activate_target(struct nfc_dev *nfc_dev, __u32 target_idx,
395 				__u32 protocol)
396 {
397 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
398 
399 	pr_debug("target_idx %d, protocol 0x%x\n", target_idx, protocol);
400 
401 	if (!test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
402 		pr_err("there is no available target to activate\n");
403 		return -EINVAL;
404 	}
405 
406 	if (ndev->target_active_prot) {
407 		pr_err("there is already an active target\n");
408 		return -EBUSY;
409 	}
410 
411 	if (!(ndev->target_available_prots & (1 << protocol))) {
412 		pr_err("target does not support the requested protocol 0x%x\n",
413 		       protocol);
414 		return -EINVAL;
415 	}
416 
417 	ndev->target_active_prot = protocol;
418 	ndev->target_available_prots = 0;
419 
420 	return 0;
421 }
422 
423 static void nci_deactivate_target(struct nfc_dev *nfc_dev, __u32 target_idx)
424 {
425 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
426 
427 	pr_debug("target_idx %d\n", target_idx);
428 
429 	if (!ndev->target_active_prot) {
430 		pr_err("unable to deactivate target, no active target\n");
431 		return;
432 	}
433 
434 	ndev->target_active_prot = 0;
435 
436 	if (test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
437 		nci_request(ndev, nci_rf_deactivate_req, 0,
438 			msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
439 	}
440 }
441 
442 static int nci_data_exchange(struct nfc_dev *nfc_dev, __u32 target_idx,
443 						struct sk_buff *skb,
444 						data_exchange_cb_t cb,
445 						void *cb_context)
446 {
447 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
448 	int rc;
449 
450 	pr_debug("target_idx %d, len %d\n", target_idx, skb->len);
451 
452 	if (!ndev->target_active_prot) {
453 		pr_err("unable to exchange data, no active target\n");
454 		return -EINVAL;
455 	}
456 
457 	if (test_and_set_bit(NCI_DATA_EXCHANGE, &ndev->flags))
458 		return -EBUSY;
459 
460 	/* store cb and context to be used on receiving data */
461 	ndev->data_exchange_cb = cb;
462 	ndev->data_exchange_cb_context = cb_context;
463 
464 	rc = nci_send_data(ndev, NCI_STATIC_RF_CONN_ID, skb);
465 	if (rc)
466 		clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
467 
468 	return rc;
469 }
470 
471 static struct nfc_ops nci_nfc_ops = {
472 	.dev_up = nci_dev_up,
473 	.dev_down = nci_dev_down,
474 	.start_poll = nci_start_poll,
475 	.stop_poll = nci_stop_poll,
476 	.activate_target = nci_activate_target,
477 	.deactivate_target = nci_deactivate_target,
478 	.data_exchange = nci_data_exchange,
479 };
480 
481 /* ---- Interface to NCI drivers ---- */
482 
483 /**
484  * nci_allocate_device - allocate a new nci device
485  *
486  * @ops: device operations
487  * @supported_protocols: NFC protocols supported by the device
488  */
489 struct nci_dev *nci_allocate_device(struct nci_ops *ops,
490 					__u32 supported_protocols,
491 					int tx_headroom,
492 					int tx_tailroom)
493 {
494 	struct nci_dev *ndev;
495 
496 	pr_debug("supported_protocols 0x%x\n", supported_protocols);
497 
498 	if (!ops->open || !ops->close || !ops->send)
499 		return NULL;
500 
501 	if (!supported_protocols)
502 		return NULL;
503 
504 	ndev = kzalloc(sizeof(struct nci_dev), GFP_KERNEL);
505 	if (!ndev)
506 		return NULL;
507 
508 	ndev->ops = ops;
509 	ndev->tx_headroom = tx_headroom;
510 	ndev->tx_tailroom = tx_tailroom;
511 
512 	ndev->nfc_dev = nfc_allocate_device(&nci_nfc_ops,
513 						supported_protocols,
514 						tx_headroom + NCI_DATA_HDR_SIZE,
515 						tx_tailroom);
516 	if (!ndev->nfc_dev)
517 		goto free_exit;
518 
519 	nfc_set_drvdata(ndev->nfc_dev, ndev);
520 
521 	return ndev;
522 
523 free_exit:
524 	kfree(ndev);
525 	return NULL;
526 }
527 EXPORT_SYMBOL(nci_allocate_device);
528 
529 /**
530  * nci_free_device - deallocate nci device
531  *
532  * @ndev: The nci device to deallocate
533  */
534 void nci_free_device(struct nci_dev *ndev)
535 {
536 	nfc_free_device(ndev->nfc_dev);
537 	kfree(ndev);
538 }
539 EXPORT_SYMBOL(nci_free_device);
540 
541 /**
542  * nci_register_device - register a nci device in the nfc subsystem
543  *
544  * @dev: The nci device to register
545  */
546 int nci_register_device(struct nci_dev *ndev)
547 {
548 	int rc;
549 	struct device *dev = &ndev->nfc_dev->dev;
550 	char name[32];
551 
552 	rc = nfc_register_device(ndev->nfc_dev);
553 	if (rc)
554 		goto exit;
555 
556 	ndev->flags = 0;
557 
558 	INIT_WORK(&ndev->cmd_work, nci_cmd_work);
559 	snprintf(name, sizeof(name), "%s_nci_cmd_wq", dev_name(dev));
560 	ndev->cmd_wq = create_singlethread_workqueue(name);
561 	if (!ndev->cmd_wq) {
562 		rc = -ENOMEM;
563 		goto unreg_exit;
564 	}
565 
566 	INIT_WORK(&ndev->rx_work, nci_rx_work);
567 	snprintf(name, sizeof(name), "%s_nci_rx_wq", dev_name(dev));
568 	ndev->rx_wq = create_singlethread_workqueue(name);
569 	if (!ndev->rx_wq) {
570 		rc = -ENOMEM;
571 		goto destroy_cmd_wq_exit;
572 	}
573 
574 	INIT_WORK(&ndev->tx_work, nci_tx_work);
575 	snprintf(name, sizeof(name), "%s_nci_tx_wq", dev_name(dev));
576 	ndev->tx_wq = create_singlethread_workqueue(name);
577 	if (!ndev->tx_wq) {
578 		rc = -ENOMEM;
579 		goto destroy_rx_wq_exit;
580 	}
581 
582 	skb_queue_head_init(&ndev->cmd_q);
583 	skb_queue_head_init(&ndev->rx_q);
584 	skb_queue_head_init(&ndev->tx_q);
585 
586 	setup_timer(&ndev->cmd_timer, nci_cmd_timer,
587 			(unsigned long) ndev);
588 
589 	mutex_init(&ndev->req_lock);
590 
591 	goto exit;
592 
593 destroy_rx_wq_exit:
594 	destroy_workqueue(ndev->rx_wq);
595 
596 destroy_cmd_wq_exit:
597 	destroy_workqueue(ndev->cmd_wq);
598 
599 unreg_exit:
600 	nfc_unregister_device(ndev->nfc_dev);
601 
602 exit:
603 	return rc;
604 }
605 EXPORT_SYMBOL(nci_register_device);
606 
607 /**
608  * nci_unregister_device - unregister a nci device in the nfc subsystem
609  *
610  * @dev: The nci device to unregister
611  */
612 void nci_unregister_device(struct nci_dev *ndev)
613 {
614 	nci_close_device(ndev);
615 
616 	destroy_workqueue(ndev->cmd_wq);
617 	destroy_workqueue(ndev->rx_wq);
618 	destroy_workqueue(ndev->tx_wq);
619 
620 	nfc_unregister_device(ndev->nfc_dev);
621 }
622 EXPORT_SYMBOL(nci_unregister_device);
623 
624 /**
625  * nci_recv_frame - receive frame from NCI drivers
626  *
627  * @skb: The sk_buff to receive
628  */
629 int nci_recv_frame(struct sk_buff *skb)
630 {
631 	struct nci_dev *ndev = (struct nci_dev *) skb->dev;
632 
633 	pr_debug("len %d\n", skb->len);
634 
635 	if (!ndev || (!test_bit(NCI_UP, &ndev->flags)
636 		&& !test_bit(NCI_INIT, &ndev->flags))) {
637 		kfree_skb(skb);
638 		return -ENXIO;
639 	}
640 
641 	/* Queue frame for rx worker thread */
642 	skb_queue_tail(&ndev->rx_q, skb);
643 	queue_work(ndev->rx_wq, &ndev->rx_work);
644 
645 	return 0;
646 }
647 EXPORT_SYMBOL(nci_recv_frame);
648 
649 static int nci_send_frame(struct sk_buff *skb)
650 {
651 	struct nci_dev *ndev = (struct nci_dev *) skb->dev;
652 
653 	pr_debug("len %d\n", skb->len);
654 
655 	if (!ndev) {
656 		kfree_skb(skb);
657 		return -ENODEV;
658 	}
659 
660 	/* Get rid of skb owner, prior to sending to the driver. */
661 	skb_orphan(skb);
662 
663 	return ndev->ops->send(skb);
664 }
665 
666 /* Send NCI command */
667 int nci_send_cmd(struct nci_dev *ndev, __u16 opcode, __u8 plen, void *payload)
668 {
669 	struct nci_ctrl_hdr *hdr;
670 	struct sk_buff *skb;
671 
672 	pr_debug("opcode 0x%x, plen %d\n", opcode, plen);
673 
674 	skb = nci_skb_alloc(ndev, (NCI_CTRL_HDR_SIZE + plen), GFP_KERNEL);
675 	if (!skb) {
676 		pr_err("no memory for command\n");
677 		return -ENOMEM;
678 	}
679 
680 	hdr = (struct nci_ctrl_hdr *) skb_put(skb, NCI_CTRL_HDR_SIZE);
681 	hdr->gid = nci_opcode_gid(opcode);
682 	hdr->oid = nci_opcode_oid(opcode);
683 	hdr->plen = plen;
684 
685 	nci_mt_set((__u8 *)hdr, NCI_MT_CMD_PKT);
686 	nci_pbf_set((__u8 *)hdr, NCI_PBF_LAST);
687 
688 	if (plen)
689 		memcpy(skb_put(skb, plen), payload, plen);
690 
691 	skb->dev = (void *) ndev;
692 
693 	skb_queue_tail(&ndev->cmd_q, skb);
694 	queue_work(ndev->cmd_wq, &ndev->cmd_work);
695 
696 	return 0;
697 }
698 
699 /* ---- NCI TX Data worker thread ---- */
700 
701 static void nci_tx_work(struct work_struct *work)
702 {
703 	struct nci_dev *ndev = container_of(work, struct nci_dev, tx_work);
704 	struct sk_buff *skb;
705 
706 	pr_debug("credits_cnt %d\n", atomic_read(&ndev->credits_cnt));
707 
708 	/* Send queued tx data */
709 	while (atomic_read(&ndev->credits_cnt)) {
710 		skb = skb_dequeue(&ndev->tx_q);
711 		if (!skb)
712 			return;
713 
714 		/* Check if data flow control is used */
715 		if (atomic_read(&ndev->credits_cnt) !=
716 				NCI_DATA_FLOW_CONTROL_NOT_USED)
717 			atomic_dec(&ndev->credits_cnt);
718 
719 		pr_debug("NCI TX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
720 			 nci_pbf(skb->data),
721 			 nci_conn_id(skb->data),
722 			 nci_plen(skb->data));
723 
724 		nci_send_frame(skb);
725 	}
726 }
727 
728 /* ----- NCI RX worker thread (data & control) ----- */
729 
730 static void nci_rx_work(struct work_struct *work)
731 {
732 	struct nci_dev *ndev = container_of(work, struct nci_dev, rx_work);
733 	struct sk_buff *skb;
734 
735 	while ((skb = skb_dequeue(&ndev->rx_q))) {
736 		/* Process frame */
737 		switch (nci_mt(skb->data)) {
738 		case NCI_MT_RSP_PKT:
739 			nci_rsp_packet(ndev, skb);
740 			break;
741 
742 		case NCI_MT_NTF_PKT:
743 			nci_ntf_packet(ndev, skb);
744 			break;
745 
746 		case NCI_MT_DATA_PKT:
747 			nci_rx_data_packet(ndev, skb);
748 			break;
749 
750 		default:
751 			pr_err("unknown MT 0x%x\n", nci_mt(skb->data));
752 			kfree_skb(skb);
753 			break;
754 		}
755 	}
756 }
757 
758 /* ----- NCI TX CMD worker thread ----- */
759 
760 static void nci_cmd_work(struct work_struct *work)
761 {
762 	struct nci_dev *ndev = container_of(work, struct nci_dev, cmd_work);
763 	struct sk_buff *skb;
764 
765 	pr_debug("cmd_cnt %d\n", atomic_read(&ndev->cmd_cnt));
766 
767 	/* Send queued command */
768 	if (atomic_read(&ndev->cmd_cnt)) {
769 		skb = skb_dequeue(&ndev->cmd_q);
770 		if (!skb)
771 			return;
772 
773 		atomic_dec(&ndev->cmd_cnt);
774 
775 		pr_debug("NCI TX: MT=cmd, PBF=%d, GID=0x%x, OID=0x%x, plen=%d\n",
776 			 nci_pbf(skb->data),
777 			 nci_opcode_gid(nci_opcode(skb->data)),
778 			 nci_opcode_oid(nci_opcode(skb->data)),
779 			 nci_plen(skb->data));
780 
781 		nci_send_frame(skb);
782 
783 		mod_timer(&ndev->cmd_timer,
784 			jiffies + msecs_to_jiffies(NCI_CMD_TIMEOUT));
785 	}
786 }
787