xref: /openbmc/linux/net/nfc/nci/hci.c (revision cf21eb6a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  The NFC Controller Interface is the communication protocol between an
4  *  NFC Controller (NFCC) and a Device Host (DH).
5  *  This is the HCI over NCI implementation, as specified in the 10.2
6  *  section of the NCI 1.1 specification.
7  *
8  *  Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
9  */
10 
11 #include <linux/skbuff.h>
12 
13 #include "../nfc.h"
14 #include <net/nfc/nci.h>
15 #include <net/nfc/nci_core.h>
16 #include <linux/nfc.h>
17 #include <linux/kcov.h>
18 
19 struct nci_data {
20 	u8 conn_id;
21 	u8 pipe;
22 	u8 cmd;
23 	const u8 *data;
24 	u32 data_len;
25 } __packed;
26 
27 struct nci_hci_create_pipe_params {
28 	u8 src_gate;
29 	u8 dest_host;
30 	u8 dest_gate;
31 } __packed;
32 
33 struct nci_hci_create_pipe_resp {
34 	u8 src_host;
35 	u8 src_gate;
36 	u8 dest_host;
37 	u8 dest_gate;
38 	u8 pipe;
39 } __packed;
40 
41 struct nci_hci_delete_pipe_noti {
42 	u8 pipe;
43 } __packed;
44 
45 struct nci_hci_all_pipe_cleared_noti {
46 	u8 host;
47 } __packed;
48 
49 struct nci_hcp_message {
50 	u8 header;      /* type -cmd,evt,rsp- + instruction */
51 	u8 data[];
52 } __packed;
53 
54 struct nci_hcp_packet {
55 	u8 header;      /* cbit+pipe */
56 	struct nci_hcp_message message;
57 } __packed;
58 
59 #define NCI_HCI_ANY_SET_PARAMETER  0x01
60 #define NCI_HCI_ANY_GET_PARAMETER  0x02
61 #define NCI_HCI_ANY_CLOSE_PIPE     0x04
62 #define NCI_HCI_ADM_CLEAR_ALL_PIPE 0x14
63 
64 #define NCI_HFP_NO_CHAINING        0x80
65 
66 #define NCI_NFCEE_ID_HCI                0x80
67 
68 #define NCI_EVT_HOT_PLUG           0x03
69 
70 #define NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY       0x01
71 #define NCI_HCI_ADM_CREATE_PIPE			0x10
72 #define NCI_HCI_ADM_DELETE_PIPE			0x11
73 
74 /* HCP headers */
75 #define NCI_HCI_HCP_PACKET_HEADER_LEN      1
76 #define NCI_HCI_HCP_MESSAGE_HEADER_LEN     1
77 #define NCI_HCI_HCP_HEADER_LEN             2
78 
79 /* HCP types */
80 #define NCI_HCI_HCP_COMMAND        0x00
81 #define NCI_HCI_HCP_EVENT          0x01
82 #define NCI_HCI_HCP_RESPONSE       0x02
83 
84 #define NCI_HCI_ADM_NOTIFY_PIPE_CREATED     0x12
85 #define NCI_HCI_ADM_NOTIFY_PIPE_DELETED     0x13
86 #define NCI_HCI_ADM_NOTIFY_ALL_PIPE_CLEARED 0x15
87 
88 #define NCI_HCI_FRAGMENT           0x7f
89 #define NCI_HCP_HEADER(type, instr) ((((type) & 0x03) << 6) |\
90 				      ((instr) & 0x3f))
91 
92 #define NCI_HCP_MSG_GET_TYPE(header) ((header & 0xc0) >> 6)
93 #define NCI_HCP_MSG_GET_CMD(header)  (header & 0x3f)
94 #define NCI_HCP_MSG_GET_PIPE(header) (header & 0x7f)
95 
96 static int nci_hci_result_to_errno(u8 result)
97 {
98 	switch (result) {
99 	case NCI_HCI_ANY_OK:
100 		return 0;
101 	case NCI_HCI_ANY_E_REG_PAR_UNKNOWN:
102 		return -EOPNOTSUPP;
103 	case NCI_HCI_ANY_E_TIMEOUT:
104 		return -ETIME;
105 	default:
106 		return -1;
107 	}
108 }
109 
110 /* HCI core */
111 static void nci_hci_reset_pipes(struct nci_hci_dev *hdev)
112 {
113 	int i;
114 
115 	for (i = 0; i < NCI_HCI_MAX_PIPES; i++) {
116 		hdev->pipes[i].gate = NCI_HCI_INVALID_GATE;
117 		hdev->pipes[i].host = NCI_HCI_INVALID_HOST;
118 	}
119 	memset(hdev->gate2pipe, NCI_HCI_INVALID_PIPE, sizeof(hdev->gate2pipe));
120 }
121 
122 static void nci_hci_reset_pipes_per_host(struct nci_dev *ndev, u8 host)
123 {
124 	int i;
125 
126 	for (i = 0; i < NCI_HCI_MAX_PIPES; i++) {
127 		if (ndev->hci_dev->pipes[i].host == host) {
128 			ndev->hci_dev->pipes[i].gate = NCI_HCI_INVALID_GATE;
129 			ndev->hci_dev->pipes[i].host = NCI_HCI_INVALID_HOST;
130 		}
131 	}
132 }
133 
134 /* Fragment HCI data over NCI packet.
135  * NFC Forum NCI 10.2.2 Data Exchange:
136  * The payload of the Data Packets sent on the Logical Connection SHALL be
137  * valid HCP packets, as defined within [ETSI_102622]. Each Data Packet SHALL
138  * contain a single HCP packet. NCI Segmentation and Reassembly SHALL NOT be
139  * applied to Data Messages in either direction. The HCI fragmentation mechanism
140  * is used if required.
141  */
142 static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
143 			     const u8 data_type, const u8 *data,
144 			     size_t data_len)
145 {
146 	const struct nci_conn_info *conn_info;
147 	struct sk_buff *skb;
148 	int len, i, r;
149 	u8 cb = pipe;
150 
151 	conn_info = ndev->hci_dev->conn_info;
152 	if (!conn_info)
153 		return -EPROTO;
154 
155 	i = 0;
156 	skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
157 			    NCI_DATA_HDR_SIZE, GFP_ATOMIC);
158 	if (!skb)
159 		return -ENOMEM;
160 
161 	skb_reserve(skb, NCI_DATA_HDR_SIZE + 2);
162 	*(u8 *)skb_push(skb, 1) = data_type;
163 
164 	do {
165 		/* If last packet add NCI_HFP_NO_CHAINING */
166 		if (i + conn_info->max_pkt_payload_len -
167 		    (skb->len + 1) >= data_len) {
168 			cb |= NCI_HFP_NO_CHAINING;
169 			len = data_len - i;
170 		} else {
171 			len = conn_info->max_pkt_payload_len - skb->len - 1;
172 		}
173 
174 		*(u8 *)skb_push(skb, 1) = cb;
175 
176 		if (len > 0)
177 			skb_put_data(skb, data + i, len);
178 
179 		r = nci_send_data(ndev, conn_info->conn_id, skb);
180 		if (r < 0)
181 			return r;
182 
183 		i += len;
184 
185 		if (i < data_len) {
186 			skb = nci_skb_alloc(ndev,
187 					    conn_info->max_pkt_payload_len +
188 					    NCI_DATA_HDR_SIZE, GFP_ATOMIC);
189 			if (!skb)
190 				return -ENOMEM;
191 
192 			skb_reserve(skb, NCI_DATA_HDR_SIZE + 1);
193 		}
194 	} while (i < data_len);
195 
196 	return i;
197 }
198 
199 static void nci_hci_send_data_req(struct nci_dev *ndev, const void *opt)
200 {
201 	const struct nci_data *data = opt;
202 
203 	nci_hci_send_data(ndev, data->pipe, data->cmd,
204 			  data->data, data->data_len);
205 }
206 
207 int nci_hci_send_event(struct nci_dev *ndev, u8 gate, u8 event,
208 		       const u8 *param, size_t param_len)
209 {
210 	u8 pipe = ndev->hci_dev->gate2pipe[gate];
211 
212 	if (pipe == NCI_HCI_INVALID_PIPE)
213 		return -EADDRNOTAVAIL;
214 
215 	return nci_hci_send_data(ndev, pipe,
216 			NCI_HCP_HEADER(NCI_HCI_HCP_EVENT, event),
217 			param, param_len);
218 }
219 EXPORT_SYMBOL(nci_hci_send_event);
220 
221 int nci_hci_send_cmd(struct nci_dev *ndev, u8 gate, u8 cmd,
222 		     const u8 *param, size_t param_len,
223 		     struct sk_buff **skb)
224 {
225 	const struct nci_hcp_message *message;
226 	const struct nci_conn_info *conn_info;
227 	struct nci_data data;
228 	int r;
229 	u8 pipe = ndev->hci_dev->gate2pipe[gate];
230 
231 	if (pipe == NCI_HCI_INVALID_PIPE)
232 		return -EADDRNOTAVAIL;
233 
234 	conn_info = ndev->hci_dev->conn_info;
235 	if (!conn_info)
236 		return -EPROTO;
237 
238 	data.conn_id = conn_info->conn_id;
239 	data.pipe = pipe;
240 	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND, cmd);
241 	data.data = param;
242 	data.data_len = param_len;
243 
244 	r = nci_request(ndev, nci_hci_send_data_req, &data,
245 			msecs_to_jiffies(NCI_DATA_TIMEOUT));
246 	if (r == NCI_STATUS_OK) {
247 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
248 		r = nci_hci_result_to_errno(
249 			NCI_HCP_MSG_GET_CMD(message->header));
250 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
251 
252 		if (!r && skb)
253 			*skb = conn_info->rx_skb;
254 	}
255 
256 	return r;
257 }
258 EXPORT_SYMBOL(nci_hci_send_cmd);
259 
260 int nci_hci_clear_all_pipes(struct nci_dev *ndev)
261 {
262 	int r;
263 
264 	r = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
265 			     NCI_HCI_ADM_CLEAR_ALL_PIPE, NULL, 0, NULL);
266 	if (r < 0)
267 		return r;
268 
269 	nci_hci_reset_pipes(ndev->hci_dev);
270 	return r;
271 }
272 EXPORT_SYMBOL(nci_hci_clear_all_pipes);
273 
274 static void nci_hci_event_received(struct nci_dev *ndev, u8 pipe,
275 				   u8 event, struct sk_buff *skb)
276 {
277 	if (ndev->ops->hci_event_received)
278 		ndev->ops->hci_event_received(ndev, pipe, event, skb);
279 }
280 
281 static void nci_hci_cmd_received(struct nci_dev *ndev, u8 pipe,
282 				 u8 cmd, struct sk_buff *skb)
283 {
284 	u8 gate = ndev->hci_dev->pipes[pipe].gate;
285 	u8 status = NCI_HCI_ANY_OK | ~NCI_HCI_FRAGMENT;
286 	u8 dest_gate, new_pipe;
287 	struct nci_hci_create_pipe_resp *create_info;
288 	struct nci_hci_delete_pipe_noti *delete_info;
289 	struct nci_hci_all_pipe_cleared_noti *cleared_info;
290 
291 	pr_debug("from gate %x pipe %x cmd %x\n", gate, pipe, cmd);
292 
293 	switch (cmd) {
294 	case NCI_HCI_ADM_NOTIFY_PIPE_CREATED:
295 		if (skb->len != 5) {
296 			status = NCI_HCI_ANY_E_NOK;
297 			goto exit;
298 		}
299 		create_info = (struct nci_hci_create_pipe_resp *)skb->data;
300 		dest_gate = create_info->dest_gate;
301 		new_pipe = create_info->pipe;
302 		if (new_pipe >= NCI_HCI_MAX_PIPES) {
303 			status = NCI_HCI_ANY_E_NOK;
304 			goto exit;
305 		}
306 
307 		/* Save the new created pipe and bind with local gate,
308 		 * the description for skb->data[3] is destination gate id
309 		 * but since we received this cmd from host controller, we
310 		 * are the destination and it is our local gate
311 		 */
312 		ndev->hci_dev->gate2pipe[dest_gate] = new_pipe;
313 		ndev->hci_dev->pipes[new_pipe].gate = dest_gate;
314 		ndev->hci_dev->pipes[new_pipe].host =
315 						create_info->src_host;
316 		break;
317 	case NCI_HCI_ANY_OPEN_PIPE:
318 		/* If the pipe is not created report an error */
319 		if (gate == NCI_HCI_INVALID_GATE) {
320 			status = NCI_HCI_ANY_E_NOK;
321 			goto exit;
322 		}
323 		break;
324 	case NCI_HCI_ADM_NOTIFY_PIPE_DELETED:
325 		if (skb->len != 1) {
326 			status = NCI_HCI_ANY_E_NOK;
327 			goto exit;
328 		}
329 		delete_info = (struct nci_hci_delete_pipe_noti *)skb->data;
330 		if (delete_info->pipe >= NCI_HCI_MAX_PIPES) {
331 			status = NCI_HCI_ANY_E_NOK;
332 			goto exit;
333 		}
334 
335 		ndev->hci_dev->pipes[delete_info->pipe].gate =
336 						NCI_HCI_INVALID_GATE;
337 		ndev->hci_dev->pipes[delete_info->pipe].host =
338 						NCI_HCI_INVALID_HOST;
339 		break;
340 	case NCI_HCI_ADM_NOTIFY_ALL_PIPE_CLEARED:
341 		if (skb->len != 1) {
342 			status = NCI_HCI_ANY_E_NOK;
343 			goto exit;
344 		}
345 
346 		cleared_info =
347 			(struct nci_hci_all_pipe_cleared_noti *)skb->data;
348 		nci_hci_reset_pipes_per_host(ndev, cleared_info->host);
349 		break;
350 	default:
351 		pr_debug("Discarded unknown cmd %x to gate %x\n", cmd, gate);
352 		break;
353 	}
354 
355 	if (ndev->ops->hci_cmd_received)
356 		ndev->ops->hci_cmd_received(ndev, pipe, cmd, skb);
357 
358 exit:
359 	nci_hci_send_data(ndev, pipe, status, NULL, 0);
360 
361 	kfree_skb(skb);
362 }
363 
364 static void nci_hci_resp_received(struct nci_dev *ndev, u8 pipe,
365 				  struct sk_buff *skb)
366 {
367 	struct nci_conn_info *conn_info;
368 
369 	conn_info = ndev->hci_dev->conn_info;
370 	if (!conn_info)
371 		goto exit;
372 
373 	conn_info->rx_skb = skb;
374 
375 exit:
376 	nci_req_complete(ndev, NCI_STATUS_OK);
377 }
378 
379 /* Receive hcp message for pipe, with type and cmd.
380  * skb contains optional message data only.
381  */
382 static void nci_hci_hcp_message_rx(struct nci_dev *ndev, u8 pipe,
383 				   u8 type, u8 instruction, struct sk_buff *skb)
384 {
385 	switch (type) {
386 	case NCI_HCI_HCP_RESPONSE:
387 		nci_hci_resp_received(ndev, pipe, skb);
388 		break;
389 	case NCI_HCI_HCP_COMMAND:
390 		nci_hci_cmd_received(ndev, pipe, instruction, skb);
391 		break;
392 	case NCI_HCI_HCP_EVENT:
393 		nci_hci_event_received(ndev, pipe, instruction, skb);
394 		break;
395 	default:
396 		pr_err("UNKNOWN MSG Type %d, instruction=%d\n",
397 		       type, instruction);
398 		kfree_skb(skb);
399 		break;
400 	}
401 
402 	nci_req_complete(ndev, NCI_STATUS_OK);
403 }
404 
405 static void nci_hci_msg_rx_work(struct work_struct *work)
406 {
407 	struct nci_hci_dev *hdev =
408 		container_of(work, struct nci_hci_dev, msg_rx_work);
409 	struct sk_buff *skb;
410 	const struct nci_hcp_message *message;
411 	u8 pipe, type, instruction;
412 
413 	for (; (skb = skb_dequeue(&hdev->msg_rx_queue)); kcov_remote_stop()) {
414 		kcov_remote_start_common(skb_get_kcov_handle(skb));
415 		pipe = NCI_HCP_MSG_GET_PIPE(skb->data[0]);
416 		skb_pull(skb, NCI_HCI_HCP_PACKET_HEADER_LEN);
417 		message = (struct nci_hcp_message *)skb->data;
418 		type = NCI_HCP_MSG_GET_TYPE(message->header);
419 		instruction = NCI_HCP_MSG_GET_CMD(message->header);
420 		skb_pull(skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
421 
422 		nci_hci_hcp_message_rx(hdev->ndev, pipe,
423 				       type, instruction, skb);
424 	}
425 }
426 
427 void nci_hci_data_received_cb(void *context,
428 			      struct sk_buff *skb, int err)
429 {
430 	struct nci_dev *ndev = (struct nci_dev *)context;
431 	struct nci_hcp_packet *packet;
432 	u8 pipe, type;
433 	struct sk_buff *hcp_skb;
434 	struct sk_buff *frag_skb;
435 	int msg_len;
436 
437 	if (err) {
438 		nci_req_complete(ndev, err);
439 		return;
440 	}
441 
442 	packet = (struct nci_hcp_packet *)skb->data;
443 	if ((packet->header & ~NCI_HCI_FRAGMENT) == 0) {
444 		skb_queue_tail(&ndev->hci_dev->rx_hcp_frags, skb);
445 		return;
446 	}
447 
448 	/* it's the last fragment. Does it need re-aggregation? */
449 	if (skb_queue_len(&ndev->hci_dev->rx_hcp_frags)) {
450 		pipe = NCI_HCP_MSG_GET_PIPE(packet->header);
451 		skb_queue_tail(&ndev->hci_dev->rx_hcp_frags, skb);
452 
453 		msg_len = 0;
454 		skb_queue_walk(&ndev->hci_dev->rx_hcp_frags, frag_skb) {
455 			msg_len += (frag_skb->len -
456 				    NCI_HCI_HCP_PACKET_HEADER_LEN);
457 		}
458 
459 		hcp_skb = nfc_alloc_recv_skb(NCI_HCI_HCP_PACKET_HEADER_LEN +
460 					     msg_len, GFP_KERNEL);
461 		if (!hcp_skb) {
462 			nci_req_complete(ndev, -ENOMEM);
463 			return;
464 		}
465 
466 		skb_put_u8(hcp_skb, pipe);
467 
468 		skb_queue_walk(&ndev->hci_dev->rx_hcp_frags, frag_skb) {
469 			msg_len = frag_skb->len - NCI_HCI_HCP_PACKET_HEADER_LEN;
470 			skb_put_data(hcp_skb,
471 				     frag_skb->data + NCI_HCI_HCP_PACKET_HEADER_LEN,
472 				     msg_len);
473 		}
474 
475 		skb_queue_purge(&ndev->hci_dev->rx_hcp_frags);
476 	} else {
477 		packet->header &= NCI_HCI_FRAGMENT;
478 		hcp_skb = skb;
479 	}
480 
481 	/* if this is a response, dispatch immediately to
482 	 * unblock waiting cmd context. Otherwise, enqueue to dispatch
483 	 * in separate context where handler can also execute command.
484 	 */
485 	packet = (struct nci_hcp_packet *)hcp_skb->data;
486 	type = NCI_HCP_MSG_GET_TYPE(packet->message.header);
487 	if (type == NCI_HCI_HCP_RESPONSE) {
488 		pipe = NCI_HCP_MSG_GET_PIPE(packet->header);
489 		skb_pull(hcp_skb, NCI_HCI_HCP_PACKET_HEADER_LEN);
490 		nci_hci_hcp_message_rx(ndev, pipe, type,
491 				       NCI_STATUS_OK, hcp_skb);
492 	} else {
493 		skb_queue_tail(&ndev->hci_dev->msg_rx_queue, hcp_skb);
494 		schedule_work(&ndev->hci_dev->msg_rx_work);
495 	}
496 }
497 
498 int nci_hci_open_pipe(struct nci_dev *ndev, u8 pipe)
499 {
500 	struct nci_data data;
501 	const struct nci_conn_info *conn_info;
502 
503 	conn_info = ndev->hci_dev->conn_info;
504 	if (!conn_info)
505 		return -EPROTO;
506 
507 	data.conn_id = conn_info->conn_id;
508 	data.pipe = pipe;
509 	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
510 				       NCI_HCI_ANY_OPEN_PIPE);
511 	data.data = NULL;
512 	data.data_len = 0;
513 
514 	return nci_request(ndev, nci_hci_send_data_req, &data,
515 			   msecs_to_jiffies(NCI_DATA_TIMEOUT));
516 }
517 EXPORT_SYMBOL(nci_hci_open_pipe);
518 
519 static u8 nci_hci_create_pipe(struct nci_dev *ndev, u8 dest_host,
520 			      u8 dest_gate, int *result)
521 {
522 	u8 pipe;
523 	struct sk_buff *skb;
524 	struct nci_hci_create_pipe_params params;
525 	const struct nci_hci_create_pipe_resp *resp;
526 
527 	pr_debug("gate=%d\n", dest_gate);
528 
529 	params.src_gate = NCI_HCI_ADMIN_GATE;
530 	params.dest_host = dest_host;
531 	params.dest_gate = dest_gate;
532 
533 	*result = nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
534 				   NCI_HCI_ADM_CREATE_PIPE,
535 				   (u8 *)&params, sizeof(params), &skb);
536 	if (*result < 0)
537 		return NCI_HCI_INVALID_PIPE;
538 
539 	resp = (struct nci_hci_create_pipe_resp *)skb->data;
540 	pipe = resp->pipe;
541 	kfree_skb(skb);
542 
543 	pr_debug("pipe created=%d\n", pipe);
544 
545 	return pipe;
546 }
547 
548 static int nci_hci_delete_pipe(struct nci_dev *ndev, u8 pipe)
549 {
550 	return nci_hci_send_cmd(ndev, NCI_HCI_ADMIN_GATE,
551 				NCI_HCI_ADM_DELETE_PIPE, &pipe, 1, NULL);
552 }
553 
554 int nci_hci_set_param(struct nci_dev *ndev, u8 gate, u8 idx,
555 		      const u8 *param, size_t param_len)
556 {
557 	const struct nci_hcp_message *message;
558 	const struct nci_conn_info *conn_info;
559 	struct nci_data data;
560 	int r;
561 	u8 *tmp;
562 	u8 pipe = ndev->hci_dev->gate2pipe[gate];
563 
564 	pr_debug("idx=%d to gate %d\n", idx, gate);
565 
566 	if (pipe == NCI_HCI_INVALID_PIPE)
567 		return -EADDRNOTAVAIL;
568 
569 	conn_info = ndev->hci_dev->conn_info;
570 	if (!conn_info)
571 		return -EPROTO;
572 
573 	tmp = kmalloc(1 + param_len, GFP_KERNEL);
574 	if (!tmp)
575 		return -ENOMEM;
576 
577 	*tmp = idx;
578 	memcpy(tmp + 1, param, param_len);
579 
580 	data.conn_id = conn_info->conn_id;
581 	data.pipe = pipe;
582 	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
583 				       NCI_HCI_ANY_SET_PARAMETER);
584 	data.data = tmp;
585 	data.data_len = param_len + 1;
586 
587 	r = nci_request(ndev, nci_hci_send_data_req, &data,
588 			msecs_to_jiffies(NCI_DATA_TIMEOUT));
589 	if (r == NCI_STATUS_OK) {
590 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
591 		r = nci_hci_result_to_errno(
592 			NCI_HCP_MSG_GET_CMD(message->header));
593 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
594 	}
595 
596 	kfree(tmp);
597 	return r;
598 }
599 EXPORT_SYMBOL(nci_hci_set_param);
600 
601 int nci_hci_get_param(struct nci_dev *ndev, u8 gate, u8 idx,
602 		      struct sk_buff **skb)
603 {
604 	const struct nci_hcp_message *message;
605 	const struct nci_conn_info *conn_info;
606 	struct nci_data data;
607 	int r;
608 	u8 pipe = ndev->hci_dev->gate2pipe[gate];
609 
610 	pr_debug("idx=%d to gate %d\n", idx, gate);
611 
612 	if (pipe == NCI_HCI_INVALID_PIPE)
613 		return -EADDRNOTAVAIL;
614 
615 	conn_info = ndev->hci_dev->conn_info;
616 	if (!conn_info)
617 		return -EPROTO;
618 
619 	data.conn_id = conn_info->conn_id;
620 	data.pipe = pipe;
621 	data.cmd = NCI_HCP_HEADER(NCI_HCI_HCP_COMMAND,
622 				  NCI_HCI_ANY_GET_PARAMETER);
623 	data.data = &idx;
624 	data.data_len = 1;
625 
626 	r = nci_request(ndev, nci_hci_send_data_req, &data,
627 			msecs_to_jiffies(NCI_DATA_TIMEOUT));
628 
629 	if (r == NCI_STATUS_OK) {
630 		message = (struct nci_hcp_message *)conn_info->rx_skb->data;
631 		r = nci_hci_result_to_errno(
632 			NCI_HCP_MSG_GET_CMD(message->header));
633 		skb_pull(conn_info->rx_skb, NCI_HCI_HCP_MESSAGE_HEADER_LEN);
634 
635 		if (!r && skb)
636 			*skb = conn_info->rx_skb;
637 	}
638 
639 	return r;
640 }
641 EXPORT_SYMBOL(nci_hci_get_param);
642 
643 int nci_hci_connect_gate(struct nci_dev *ndev,
644 			 u8 dest_host, u8 dest_gate, u8 pipe)
645 {
646 	bool pipe_created = false;
647 	int r;
648 
649 	if (pipe == NCI_HCI_DO_NOT_OPEN_PIPE)
650 		return 0;
651 
652 	if (ndev->hci_dev->gate2pipe[dest_gate] != NCI_HCI_INVALID_PIPE)
653 		return -EADDRINUSE;
654 
655 	if (pipe != NCI_HCI_INVALID_PIPE)
656 		goto open_pipe;
657 
658 	switch (dest_gate) {
659 	case NCI_HCI_LINK_MGMT_GATE:
660 		pipe = NCI_HCI_LINK_MGMT_PIPE;
661 	break;
662 	case NCI_HCI_ADMIN_GATE:
663 		pipe = NCI_HCI_ADMIN_PIPE;
664 	break;
665 	default:
666 		pipe = nci_hci_create_pipe(ndev, dest_host, dest_gate, &r);
667 		if (pipe == NCI_HCI_INVALID_PIPE)
668 			return r;
669 		pipe_created = true;
670 		break;
671 	}
672 
673 open_pipe:
674 	r = nci_hci_open_pipe(ndev, pipe);
675 	if (r < 0) {
676 		if (pipe_created) {
677 			if (nci_hci_delete_pipe(ndev, pipe) < 0) {
678 				/* TODO: Cannot clean by deleting pipe...
679 				 * -> inconsistent state
680 				 */
681 			}
682 		}
683 		return r;
684 	}
685 
686 	ndev->hci_dev->pipes[pipe].gate = dest_gate;
687 	ndev->hci_dev->pipes[pipe].host = dest_host;
688 	ndev->hci_dev->gate2pipe[dest_gate] = pipe;
689 
690 	return 0;
691 }
692 EXPORT_SYMBOL(nci_hci_connect_gate);
693 
694 static int nci_hci_dev_connect_gates(struct nci_dev *ndev,
695 				     u8 gate_count,
696 				     const struct nci_hci_gate *gates)
697 {
698 	int r;
699 
700 	while (gate_count--) {
701 		r = nci_hci_connect_gate(ndev, gates->dest_host,
702 					 gates->gate, gates->pipe);
703 		if (r < 0)
704 			return r;
705 		gates++;
706 	}
707 
708 	return 0;
709 }
710 
711 int nci_hci_dev_session_init(struct nci_dev *ndev)
712 {
713 	struct nci_conn_info *conn_info;
714 	struct sk_buff *skb;
715 	int r;
716 
717 	ndev->hci_dev->count_pipes = 0;
718 	ndev->hci_dev->expected_pipes = 0;
719 
720 	conn_info = ndev->hci_dev->conn_info;
721 	if (!conn_info)
722 		return -EPROTO;
723 
724 	conn_info->data_exchange_cb = nci_hci_data_received_cb;
725 	conn_info->data_exchange_cb_context = ndev;
726 
727 	nci_hci_reset_pipes(ndev->hci_dev);
728 
729 	if (ndev->hci_dev->init_data.gates[0].gate != NCI_HCI_ADMIN_GATE)
730 		return -EPROTO;
731 
732 	r = nci_hci_connect_gate(ndev,
733 				 ndev->hci_dev->init_data.gates[0].dest_host,
734 				 ndev->hci_dev->init_data.gates[0].gate,
735 				 ndev->hci_dev->init_data.gates[0].pipe);
736 	if (r < 0)
737 		return r;
738 
739 	r = nci_hci_get_param(ndev, NCI_HCI_ADMIN_GATE,
740 			      NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY, &skb);
741 	if (r < 0)
742 		return r;
743 
744 	if (skb->len &&
745 	    skb->len == strlen(ndev->hci_dev->init_data.session_id) &&
746 	    !memcmp(ndev->hci_dev->init_data.session_id, skb->data, skb->len) &&
747 	    ndev->ops->hci_load_session) {
748 		/* Restore gate<->pipe table from some proprietary location. */
749 		r = ndev->ops->hci_load_session(ndev);
750 	} else {
751 		r = nci_hci_clear_all_pipes(ndev);
752 		if (r < 0)
753 			goto exit;
754 
755 		r = nci_hci_dev_connect_gates(ndev,
756 					      ndev->hci_dev->init_data.gate_count,
757 					      ndev->hci_dev->init_data.gates);
758 		if (r < 0)
759 			goto exit;
760 
761 		r = nci_hci_set_param(ndev, NCI_HCI_ADMIN_GATE,
762 				      NCI_HCI_ADMIN_PARAM_SESSION_IDENTITY,
763 				      ndev->hci_dev->init_data.session_id,
764 				      strlen(ndev->hci_dev->init_data.session_id));
765 	}
766 
767 exit:
768 	kfree_skb(skb);
769 
770 	return r;
771 }
772 EXPORT_SYMBOL(nci_hci_dev_session_init);
773 
774 struct nci_hci_dev *nci_hci_allocate(struct nci_dev *ndev)
775 {
776 	struct nci_hci_dev *hdev;
777 
778 	hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
779 	if (!hdev)
780 		return NULL;
781 
782 	skb_queue_head_init(&hdev->rx_hcp_frags);
783 	INIT_WORK(&hdev->msg_rx_work, nci_hci_msg_rx_work);
784 	skb_queue_head_init(&hdev->msg_rx_queue);
785 	hdev->ndev = ndev;
786 
787 	return hdev;
788 }
789 
790 void nci_hci_deallocate(struct nci_dev *ndev)
791 {
792 	kfree(ndev->hci_dev);
793 }
794