1 /*
2  * Copyright (c) 2007-2011 Atheros Communications Inc.
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "core.h"
18 #include "debug.h"
19 #include "hif-ops.h"
20 
21 #define HTC_PACKET_CONTAINER_ALLOCATION 32
22 #define HTC_CONTROL_BUFFER_SIZE (HTC_MAX_CTRL_MSG_LEN + HTC_HDR_LENGTH)
23 
24 static int ath6kl_htc_pipe_tx(struct htc_target *handle,
25 			      struct htc_packet *packet);
26 static void ath6kl_htc_pipe_cleanup(struct htc_target *handle);
27 
28 /* htc pipe tx path */
29 static inline void restore_tx_packet(struct htc_packet *packet)
30 {
31 	if (packet->info.tx.flags & HTC_FLAGS_TX_FIXUP_NETBUF) {
32 		skb_pull(packet->skb, sizeof(struct htc_frame_hdr));
33 		packet->info.tx.flags &= ~HTC_FLAGS_TX_FIXUP_NETBUF;
34 	}
35 }
36 
37 static void do_send_completion(struct htc_endpoint *ep,
38 			       struct list_head *queue_to_indicate)
39 {
40 	struct htc_packet *packet;
41 
42 	if (list_empty(queue_to_indicate)) {
43 		/* nothing to indicate */
44 		return;
45 	}
46 
47 	if (ep->ep_cb.tx_comp_multi != NULL) {
48 		ath6kl_dbg(ATH6KL_DBG_HTC,
49 			   "%s: calling ep %d, send complete multiple callback (%d pkts)\n",
50 			   __func__, ep->eid,
51 			   get_queue_depth(queue_to_indicate));
52 		/*
53 		 * a multiple send complete handler is being used,
54 		 * pass the queue to the handler
55 		 */
56 		ep->ep_cb.tx_comp_multi(ep->target, queue_to_indicate);
57 		/*
58 		 * all packets are now owned by the callback,
59 		 * reset queue to be safe
60 		 */
61 		INIT_LIST_HEAD(queue_to_indicate);
62 	} else {
63 		/* using legacy EpTxComplete */
64 		do {
65 			packet = list_first_entry(queue_to_indicate,
66 						  struct htc_packet, list);
67 
68 			list_del(&packet->list);
69 			ath6kl_dbg(ATH6KL_DBG_HTC,
70 				   "%s: calling ep %d send complete callback on packet 0x%p\n",
71 				   __func__, ep->eid, packet);
72 			ep->ep_cb.tx_complete(ep->target, packet);
73 		} while (!list_empty(queue_to_indicate));
74 	}
75 }
76 
77 static void send_packet_completion(struct htc_target *target,
78 				   struct htc_packet *packet)
79 {
80 	struct htc_endpoint *ep = &target->endpoint[packet->endpoint];
81 	struct list_head container;
82 
83 	restore_tx_packet(packet);
84 	INIT_LIST_HEAD(&container);
85 	list_add_tail(&packet->list, &container);
86 
87 	/* do completion */
88 	do_send_completion(ep, &container);
89 }
90 
91 static void get_htc_packet_credit_based(struct htc_target *target,
92 					struct htc_endpoint *ep,
93 					struct list_head *queue)
94 {
95 	int credits_required;
96 	int remainder;
97 	u8 send_flags;
98 	struct htc_packet *packet;
99 	unsigned int transfer_len;
100 
101 	/* NOTE : the TX lock is held when this function is called */
102 
103 	/* loop until we can grab as many packets out of the queue as we can */
104 	while (true) {
105 		send_flags = 0;
106 		if (list_empty(&ep->txq))
107 			break;
108 
109 		/* get packet at head, but don't remove it */
110 		packet = list_first_entry(&ep->txq, struct htc_packet, list);
111 
112 		ath6kl_dbg(ATH6KL_DBG_HTC,
113 			   "%s: got head packet:0x%p , queue depth: %d\n",
114 			   __func__, packet, get_queue_depth(&ep->txq));
115 
116 		transfer_len = packet->act_len + HTC_HDR_LENGTH;
117 
118 		if (transfer_len <= target->tgt_cred_sz) {
119 			credits_required = 1;
120 		} else {
121 			/* figure out how many credits this message requires */
122 			credits_required = transfer_len / target->tgt_cred_sz;
123 			remainder = transfer_len % target->tgt_cred_sz;
124 
125 			if (remainder)
126 				credits_required++;
127 		}
128 
129 		ath6kl_dbg(ATH6KL_DBG_HTC, "%s: creds required:%d got:%d\n",
130 			   __func__, credits_required, ep->cred_dist.credits);
131 
132 		if (ep->eid == ENDPOINT_0) {
133 			/*
134 			 * endpoint 0 is special, it always has a credit and
135 			 * does not require credit based flow control
136 			 */
137 			credits_required = 0;
138 
139 		} else {
140 			if (ep->cred_dist.credits < credits_required)
141 				break;
142 
143 			ep->cred_dist.credits -= credits_required;
144 			ep->ep_st.cred_cosumd += credits_required;
145 
146 			/* check if we need credits back from the target */
147 			if (ep->cred_dist.credits <
148 					ep->cred_dist.cred_per_msg) {
149 				/* tell the target we need credits ASAP! */
150 				send_flags |= HTC_FLAGS_NEED_CREDIT_UPDATE;
151 				ep->ep_st.cred_low_indicate += 1;
152 				ath6kl_dbg(ATH6KL_DBG_HTC,
153 					   "%s: host needs credits\n",
154 					   __func__);
155 			}
156 		}
157 
158 		/* now we can fully dequeue */
159 		packet = list_first_entry(&ep->txq, struct htc_packet, list);
160 
161 		list_del(&packet->list);
162 		/* save the number of credits this packet consumed */
163 		packet->info.tx.cred_used = credits_required;
164 		/* save send flags */
165 		packet->info.tx.flags = send_flags;
166 		packet->info.tx.seqno = ep->seqno;
167 		ep->seqno++;
168 		/* queue this packet into the caller's queue */
169 		list_add_tail(&packet->list, queue);
170 	}
171 }
172 
173 static void get_htc_packet(struct htc_target *target,
174 			   struct htc_endpoint *ep,
175 			   struct list_head *queue, int resources)
176 {
177 	struct htc_packet *packet;
178 
179 	/* NOTE : the TX lock is held when this function is called */
180 
181 	/* loop until we can grab as many packets out of the queue as we can */
182 	while (resources) {
183 		if (list_empty(&ep->txq))
184 			break;
185 
186 		packet = list_first_entry(&ep->txq, struct htc_packet, list);
187 		list_del(&packet->list);
188 
189 		ath6kl_dbg(ATH6KL_DBG_HTC,
190 			   "%s: got packet:0x%p , new queue depth: %d\n",
191 			   __func__, packet, get_queue_depth(&ep->txq));
192 		packet->info.tx.seqno = ep->seqno;
193 		packet->info.tx.flags = 0;
194 		packet->info.tx.cred_used = 0;
195 		ep->seqno++;
196 
197 		/* queue this packet into the caller's queue */
198 		list_add_tail(&packet->list, queue);
199 		resources--;
200 	}
201 }
202 
203 static int htc_issue_packets(struct htc_target *target,
204 			     struct htc_endpoint *ep,
205 			     struct list_head *pkt_queue)
206 {
207 	int status = 0;
208 	u16 payload_len;
209 	struct sk_buff *skb;
210 	struct htc_frame_hdr *htc_hdr;
211 	struct htc_packet *packet;
212 
213 	ath6kl_dbg(ATH6KL_DBG_HTC,
214 		   "%s: queue: 0x%p, pkts %d\n", __func__,
215 		   pkt_queue, get_queue_depth(pkt_queue));
216 
217 	while (!list_empty(pkt_queue)) {
218 		packet = list_first_entry(pkt_queue, struct htc_packet, list);
219 		list_del(&packet->list);
220 
221 		skb = packet->skb;
222 		if (!skb) {
223 			WARN_ON_ONCE(1);
224 			status = -EINVAL;
225 			break;
226 		}
227 
228 		payload_len = packet->act_len;
229 
230 		/* setup HTC frame header */
231 		htc_hdr = skb_push(skb, sizeof(*htc_hdr));
232 		if (!htc_hdr) {
233 			WARN_ON_ONCE(1);
234 			status = -EINVAL;
235 			break;
236 		}
237 
238 		packet->info.tx.flags |= HTC_FLAGS_TX_FIXUP_NETBUF;
239 
240 		/* Endianess? */
241 		put_unaligned((u16) payload_len, &htc_hdr->payld_len);
242 		htc_hdr->flags = packet->info.tx.flags;
243 		htc_hdr->eid = (u8) packet->endpoint;
244 		htc_hdr->ctrl[0] = 0;
245 		htc_hdr->ctrl[1] = (u8) packet->info.tx.seqno;
246 
247 		spin_lock_bh(&target->tx_lock);
248 
249 		/* store in look up queue to match completions */
250 		list_add_tail(&packet->list, &ep->pipe.tx_lookup_queue);
251 		ep->ep_st.tx_issued += 1;
252 		spin_unlock_bh(&target->tx_lock);
253 
254 		status = ath6kl_hif_pipe_send(target->dev->ar,
255 					      ep->pipe.pipeid_ul, NULL, skb);
256 
257 		if (status != 0) {
258 			if (status != -ENOMEM) {
259 				/* TODO: if more than 1 endpoint maps to the
260 				 * same PipeID, it is possible to run out of
261 				 * resources in the HIF layer.
262 				 * Don't emit the error
263 				 */
264 				ath6kl_dbg(ATH6KL_DBG_HTC,
265 					   "%s: failed status:%d\n",
266 					   __func__, status);
267 			}
268 			spin_lock_bh(&target->tx_lock);
269 			list_del(&packet->list);
270 
271 			/* reclaim credits */
272 			ep->cred_dist.credits += packet->info.tx.cred_used;
273 			spin_unlock_bh(&target->tx_lock);
274 
275 			/* put it back into the callers queue */
276 			list_add(&packet->list, pkt_queue);
277 			break;
278 		}
279 	}
280 
281 	if (status != 0) {
282 		while (!list_empty(pkt_queue)) {
283 			if (status != -ENOMEM) {
284 				ath6kl_dbg(ATH6KL_DBG_HTC,
285 					   "%s: failed pkt:0x%p status:%d\n",
286 					   __func__, packet, status);
287 			}
288 
289 			packet = list_first_entry(pkt_queue,
290 						  struct htc_packet, list);
291 			list_del(&packet->list);
292 			packet->status = status;
293 			send_packet_completion(target, packet);
294 		}
295 	}
296 
297 	return status;
298 }
299 
300 static enum htc_send_queue_result htc_try_send(struct htc_target *target,
301 					       struct htc_endpoint *ep,
302 					       struct list_head *txq)
303 {
304 	struct list_head send_queue;	/* temp queue to hold packets */
305 	struct htc_packet *packet, *tmp_pkt;
306 	struct ath6kl *ar = target->dev->ar;
307 	enum htc_send_full_action action;
308 	int tx_resources, overflow, txqueue_depth, i, good_pkts;
309 	u8 pipeid;
310 
311 	ath6kl_dbg(ATH6KL_DBG_HTC, "%s: (queue:0x%p depth:%d)\n",
312 		   __func__, txq,
313 		   (txq == NULL) ? 0 : get_queue_depth(txq));
314 
315 	/* init the local send queue */
316 	INIT_LIST_HEAD(&send_queue);
317 
318 	/*
319 	 * txq equals to NULL means
320 	 * caller didn't provide a queue, just wants us to
321 	 * check queues and send
322 	 */
323 	if (txq != NULL) {
324 		if (list_empty(txq)) {
325 			/* empty queue */
326 			return HTC_SEND_QUEUE_DROP;
327 		}
328 
329 		spin_lock_bh(&target->tx_lock);
330 		txqueue_depth = get_queue_depth(&ep->txq);
331 		spin_unlock_bh(&target->tx_lock);
332 
333 		if (txqueue_depth >= ep->max_txq_depth) {
334 			/* we've already overflowed */
335 			overflow = get_queue_depth(txq);
336 		} else {
337 			/* get how much we will overflow by */
338 			overflow = txqueue_depth;
339 			overflow += get_queue_depth(txq);
340 			/* get how much we will overflow the TX queue by */
341 			overflow -= ep->max_txq_depth;
342 		}
343 
344 		/* if overflow is negative or zero, we are okay */
345 		if (overflow > 0) {
346 			ath6kl_dbg(ATH6KL_DBG_HTC,
347 				   "%s: Endpoint %d, TX queue will overflow :%d, Tx Depth:%d, Max:%d\n",
348 				   __func__, ep->eid, overflow, txqueue_depth,
349 				   ep->max_txq_depth);
350 		}
351 		if ((overflow <= 0) ||
352 		    (ep->ep_cb.tx_full == NULL)) {
353 			/*
354 			 * all packets will fit or caller did not provide send
355 			 * full indication handler -- just move all of them
356 			 * to the local send_queue object
357 			 */
358 			list_splice_tail_init(txq, &send_queue);
359 		} else {
360 			good_pkts = get_queue_depth(txq) - overflow;
361 			if (good_pkts < 0) {
362 				WARN_ON_ONCE(1);
363 				return HTC_SEND_QUEUE_DROP;
364 			}
365 
366 			/* we have overflowed, and a callback is provided */
367 			/* dequeue all non-overflow packets to the sendqueue */
368 			for (i = 0; i < good_pkts; i++) {
369 				/* pop off caller's queue */
370 				packet = list_first_entry(txq,
371 							  struct htc_packet,
372 							  list);
373 				/* move to local queue */
374 				list_move_tail(&packet->list, &send_queue);
375 			}
376 
377 			/*
378 			 * the caller's queue has all the packets that won't fit
379 			 * walk through the caller's queue and indicate each to
380 			 * the send full handler
381 			 */
382 			list_for_each_entry_safe(packet, tmp_pkt,
383 						 txq, list) {
384 				ath6kl_dbg(ATH6KL_DBG_HTC,
385 					   "%s: Indicate overflowed TX pkts: %p\n",
386 					   __func__, packet);
387 				action = ep->ep_cb.tx_full(ep->target, packet);
388 				if (action == HTC_SEND_FULL_DROP) {
389 					/* callback wants the packet dropped */
390 					ep->ep_st.tx_dropped += 1;
391 
392 					/* leave this one in the caller's queue
393 					 * for cleanup */
394 				} else {
395 					/* callback wants to keep this packet,
396 					 * move from caller's queue to the send
397 					 * queue */
398 					list_move_tail(&packet->list,
399 						       &send_queue);
400 				}
401 			}
402 
403 			if (list_empty(&send_queue)) {
404 				/* no packets made it in, caller will cleanup */
405 				return HTC_SEND_QUEUE_DROP;
406 			}
407 		}
408 	}
409 
410 	if (!ep->pipe.tx_credit_flow_enabled) {
411 		tx_resources =
412 		    ath6kl_hif_pipe_get_free_queue_number(ar,
413 							  ep->pipe.pipeid_ul);
414 	} else {
415 		tx_resources = 0;
416 	}
417 
418 	spin_lock_bh(&target->tx_lock);
419 	if (!list_empty(&send_queue)) {
420 		/* transfer packets to tail */
421 		list_splice_tail_init(&send_queue, &ep->txq);
422 		if (!list_empty(&send_queue)) {
423 			WARN_ON_ONCE(1);
424 			spin_unlock_bh(&target->tx_lock);
425 			return HTC_SEND_QUEUE_DROP;
426 		}
427 		INIT_LIST_HEAD(&send_queue);
428 	}
429 
430 	/* increment tx processing count on entry */
431 	ep->tx_proc_cnt++;
432 
433 	if (ep->tx_proc_cnt > 1) {
434 		/*
435 		 * Another thread or task is draining the TX queues on this
436 		 * endpoint that thread will reset the tx processing count
437 		 * when the queue is drained.
438 		 */
439 		ep->tx_proc_cnt--;
440 		spin_unlock_bh(&target->tx_lock);
441 		return HTC_SEND_QUEUE_OK;
442 	}
443 
444 	/***** beyond this point only 1 thread may enter ******/
445 
446 	/*
447 	 * Now drain the endpoint TX queue for transmission as long as we have
448 	 * enough transmit resources.
449 	 */
450 	while (true) {
451 		if (get_queue_depth(&ep->txq) == 0)
452 			break;
453 
454 		if (ep->pipe.tx_credit_flow_enabled) {
455 			/*
456 			 * Credit based mechanism provides flow control
457 			 * based on target transmit resource availability,
458 			 * we assume that the HIF layer will always have
459 			 * bus resources greater than target transmit
460 			 * resources.
461 			 */
462 			get_htc_packet_credit_based(target, ep, &send_queue);
463 		} else {
464 			/*
465 			 * Get all packets for this endpoint that we can
466 			 * for this pass.
467 			 */
468 			get_htc_packet(target, ep, &send_queue, tx_resources);
469 		}
470 
471 		if (get_queue_depth(&send_queue) == 0) {
472 			/*
473 			 * Didn't get packets due to out of resources or TX
474 			 * queue was drained.
475 			 */
476 			break;
477 		}
478 
479 		spin_unlock_bh(&target->tx_lock);
480 
481 		/* send what we can */
482 		htc_issue_packets(target, ep, &send_queue);
483 
484 		if (!ep->pipe.tx_credit_flow_enabled) {
485 			pipeid = ep->pipe.pipeid_ul;
486 			tx_resources =
487 			    ath6kl_hif_pipe_get_free_queue_number(ar, pipeid);
488 		}
489 
490 		spin_lock_bh(&target->tx_lock);
491 	}
492 
493 	/* done with this endpoint, we can clear the count */
494 	ep->tx_proc_cnt = 0;
495 	spin_unlock_bh(&target->tx_lock);
496 
497 	return HTC_SEND_QUEUE_OK;
498 }
499 
500 /* htc control packet manipulation */
501 static void destroy_htc_txctrl_packet(struct htc_packet *packet)
502 {
503 	struct sk_buff *skb;
504 	skb = packet->skb;
505 	dev_kfree_skb(skb);
506 	kfree(packet);
507 }
508 
509 static struct htc_packet *build_htc_txctrl_packet(void)
510 {
511 	struct htc_packet *packet = NULL;
512 	struct sk_buff *skb;
513 
514 	packet = kzalloc(sizeof(struct htc_packet), GFP_KERNEL);
515 	if (packet == NULL)
516 		return NULL;
517 
518 	skb = __dev_alloc_skb(HTC_CONTROL_BUFFER_SIZE, GFP_KERNEL);
519 
520 	if (skb == NULL) {
521 		kfree(packet);
522 		return NULL;
523 	}
524 	packet->skb = skb;
525 
526 	return packet;
527 }
528 
529 static void htc_free_txctrl_packet(struct htc_target *target,
530 				   struct htc_packet *packet)
531 {
532 	destroy_htc_txctrl_packet(packet);
533 }
534 
535 static struct htc_packet *htc_alloc_txctrl_packet(struct htc_target *target)
536 {
537 	return build_htc_txctrl_packet();
538 }
539 
540 static void htc_txctrl_complete(struct htc_target *target,
541 				struct htc_packet *packet)
542 {
543 	htc_free_txctrl_packet(target, packet);
544 }
545 
546 #define MAX_MESSAGE_SIZE 1536
547 
548 static int htc_setup_target_buffer_assignments(struct htc_target *target)
549 {
550 	int status, credits, credit_per_maxmsg, i;
551 	struct htc_pipe_txcredit_alloc *entry;
552 	unsigned int hif_usbaudioclass = 0;
553 
554 	credit_per_maxmsg = MAX_MESSAGE_SIZE / target->tgt_cred_sz;
555 	if (MAX_MESSAGE_SIZE % target->tgt_cred_sz)
556 		credit_per_maxmsg++;
557 
558 	/* TODO, this should be configured by the caller! */
559 
560 	credits = target->tgt_creds;
561 	entry = &target->pipe.txcredit_alloc[0];
562 
563 	status = -ENOMEM;
564 
565 	/* FIXME: hif_usbaudioclass is always zero */
566 	if (hif_usbaudioclass) {
567 		ath6kl_dbg(ATH6KL_DBG_HTC,
568 			   "%s: For USB Audio Class- Total:%d\n",
569 			   __func__, credits);
570 		entry++;
571 		entry++;
572 		/* Setup VO Service To have Max Credits */
573 		entry->service_id = WMI_DATA_VO_SVC;
574 		entry->credit_alloc = (credits - 6);
575 		if (entry->credit_alloc == 0)
576 			entry->credit_alloc++;
577 
578 		credits -= (int) entry->credit_alloc;
579 		if (credits <= 0)
580 			return status;
581 
582 		entry++;
583 		entry->service_id = WMI_CONTROL_SVC;
584 		entry->credit_alloc = credit_per_maxmsg;
585 		credits -= (int) entry->credit_alloc;
586 		if (credits <= 0)
587 			return status;
588 
589 		/* leftovers go to best effort */
590 		entry++;
591 		entry++;
592 		entry->service_id = WMI_DATA_BE_SVC;
593 		entry->credit_alloc = (u8) credits;
594 		status = 0;
595 	} else {
596 		entry++;
597 		entry->service_id = WMI_DATA_VI_SVC;
598 		entry->credit_alloc = credits / 4;
599 		if (entry->credit_alloc == 0)
600 			entry->credit_alloc++;
601 
602 		credits -= (int) entry->credit_alloc;
603 		if (credits <= 0)
604 			return status;
605 
606 		entry++;
607 		entry->service_id = WMI_DATA_VO_SVC;
608 		entry->credit_alloc = credits / 4;
609 		if (entry->credit_alloc == 0)
610 			entry->credit_alloc++;
611 
612 		credits -= (int) entry->credit_alloc;
613 		if (credits <= 0)
614 			return status;
615 
616 		entry++;
617 		entry->service_id = WMI_CONTROL_SVC;
618 		entry->credit_alloc = credit_per_maxmsg;
619 		credits -= (int) entry->credit_alloc;
620 		if (credits <= 0)
621 			return status;
622 
623 		entry++;
624 		entry->service_id = WMI_DATA_BK_SVC;
625 		entry->credit_alloc = credit_per_maxmsg;
626 		credits -= (int) entry->credit_alloc;
627 		if (credits <= 0)
628 			return status;
629 
630 		/* leftovers go to best effort */
631 		entry++;
632 		entry->service_id = WMI_DATA_BE_SVC;
633 		entry->credit_alloc = (u8) credits;
634 		status = 0;
635 	}
636 
637 	if (status == 0) {
638 		for (i = 0; i < ENDPOINT_MAX; i++) {
639 			if (target->pipe.txcredit_alloc[i].service_id != 0) {
640 				ath6kl_dbg(ATH6KL_DBG_HTC,
641 					   "HTC Service Index : %d TX : 0x%2.2X : alloc:%d\n",
642 					   i,
643 					   target->pipe.txcredit_alloc[i].
644 					   service_id,
645 					   target->pipe.txcredit_alloc[i].
646 					   credit_alloc);
647 			}
648 		}
649 	}
650 	return status;
651 }
652 
653 /* process credit reports and call distribution function */
654 static void htc_process_credit_report(struct htc_target *target,
655 				      struct htc_credit_report *rpt,
656 				      int num_entries,
657 				      enum htc_endpoint_id from_ep)
658 {
659 	int total_credits = 0, i;
660 	struct htc_endpoint *ep;
661 
662 	/* lock out TX while we update credits */
663 	spin_lock_bh(&target->tx_lock);
664 
665 	for (i = 0; i < num_entries; i++, rpt++) {
666 		if (rpt->eid >= ENDPOINT_MAX) {
667 			WARN_ON_ONCE(1);
668 			spin_unlock_bh(&target->tx_lock);
669 			return;
670 		}
671 
672 		ep = &target->endpoint[rpt->eid];
673 		ep->cred_dist.credits += rpt->credits;
674 
675 		if (ep->cred_dist.credits && get_queue_depth(&ep->txq)) {
676 			spin_unlock_bh(&target->tx_lock);
677 			htc_try_send(target, ep, NULL);
678 			spin_lock_bh(&target->tx_lock);
679 		}
680 
681 		total_credits += rpt->credits;
682 	}
683 	ath6kl_dbg(ATH6KL_DBG_HTC,
684 		   "Report indicated %d credits to distribute\n",
685 		   total_credits);
686 
687 	spin_unlock_bh(&target->tx_lock);
688 }
689 
690 /* flush endpoint TX queue */
691 static void htc_flush_tx_endpoint(struct htc_target *target,
692 				  struct htc_endpoint *ep, u16 tag)
693 {
694 	struct htc_packet *packet;
695 
696 	spin_lock_bh(&target->tx_lock);
697 	while (get_queue_depth(&ep->txq)) {
698 		packet = list_first_entry(&ep->txq, struct htc_packet, list);
699 		list_del(&packet->list);
700 		packet->status = 0;
701 		send_packet_completion(target, packet);
702 	}
703 	spin_unlock_bh(&target->tx_lock);
704 }
705 
706 /*
707  * In the adapted HIF layer, struct sk_buff * are passed between HIF and HTC,
708  * since upper layers expects struct htc_packet containers we use the completed
709  * skb and lookup it's corresponding HTC packet buffer from a lookup list.
710  * This is extra overhead that can be fixed by re-aligning HIF interfaces with
711  * HTC.
712  */
713 static struct htc_packet *htc_lookup_tx_packet(struct htc_target *target,
714 					       struct htc_endpoint *ep,
715 					       struct sk_buff *skb)
716 {
717 	struct htc_packet *packet, *tmp_pkt, *found_packet = NULL;
718 
719 	spin_lock_bh(&target->tx_lock);
720 
721 	/*
722 	 * interate from the front of tx lookup queue
723 	 * this lookup should be fast since lower layers completes in-order and
724 	 * so the completed packet should be at the head of the list generally
725 	 */
726 	list_for_each_entry_safe(packet, tmp_pkt, &ep->pipe.tx_lookup_queue,
727 				 list) {
728 		/* check for removal */
729 		if (skb == packet->skb) {
730 			/* found it */
731 			list_del(&packet->list);
732 			found_packet = packet;
733 			break;
734 		}
735 	}
736 
737 	spin_unlock_bh(&target->tx_lock);
738 
739 	return found_packet;
740 }
741 
742 static int ath6kl_htc_pipe_tx_complete(struct ath6kl *ar, struct sk_buff *skb)
743 {
744 	struct htc_target *target = ar->htc_target;
745 	struct htc_frame_hdr *htc_hdr;
746 	struct htc_endpoint *ep;
747 	struct htc_packet *packet;
748 	u8 ep_id, *netdata;
749 
750 	netdata = skb->data;
751 
752 	htc_hdr = (struct htc_frame_hdr *) netdata;
753 
754 	ep_id = htc_hdr->eid;
755 	ep = &target->endpoint[ep_id];
756 
757 	packet = htc_lookup_tx_packet(target, ep, skb);
758 	if (packet == NULL) {
759 		/* may have already been flushed and freed */
760 		ath6kl_err("HTC TX lookup failed!\n");
761 	} else {
762 		/* will be giving this buffer back to upper layers */
763 		packet->status = 0;
764 		send_packet_completion(target, packet);
765 	}
766 	skb = NULL;
767 
768 	if (!ep->pipe.tx_credit_flow_enabled) {
769 		/*
770 		 * note: when using TX credit flow, the re-checking of queues
771 		 * happens when credits flow back from the target. in the
772 		 * non-TX credit case, we recheck after the packet completes
773 		 */
774 		htc_try_send(target, ep, NULL);
775 	}
776 
777 	return 0;
778 }
779 
780 static int htc_send_packets_multiple(struct htc_target *target,
781 				     struct list_head *pkt_queue)
782 {
783 	struct htc_endpoint *ep;
784 	struct htc_packet *packet, *tmp_pkt;
785 
786 	if (list_empty(pkt_queue))
787 		return -EINVAL;
788 
789 	/* get first packet to find out which ep the packets will go into */
790 	packet = list_first_entry(pkt_queue, struct htc_packet, list);
791 
792 	if (packet->endpoint >= ENDPOINT_MAX) {
793 		WARN_ON_ONCE(1);
794 		return -EINVAL;
795 	}
796 	ep = &target->endpoint[packet->endpoint];
797 
798 	htc_try_send(target, ep, pkt_queue);
799 
800 	/* do completion on any packets that couldn't get in */
801 	if (!list_empty(pkt_queue)) {
802 		list_for_each_entry_safe(packet, tmp_pkt, pkt_queue, list) {
803 			packet->status = -ENOMEM;
804 		}
805 
806 		do_send_completion(ep, pkt_queue);
807 	}
808 
809 	return 0;
810 }
811 
812 /* htc pipe rx path */
813 static struct htc_packet *alloc_htc_packet_container(struct htc_target *target)
814 {
815 	struct htc_packet *packet;
816 	spin_lock_bh(&target->rx_lock);
817 
818 	if (target->pipe.htc_packet_pool == NULL) {
819 		spin_unlock_bh(&target->rx_lock);
820 		return NULL;
821 	}
822 
823 	packet = target->pipe.htc_packet_pool;
824 	target->pipe.htc_packet_pool = (struct htc_packet *) packet->list.next;
825 
826 	spin_unlock_bh(&target->rx_lock);
827 
828 	packet->list.next = NULL;
829 	return packet;
830 }
831 
832 static void free_htc_packet_container(struct htc_target *target,
833 				      struct htc_packet *packet)
834 {
835 	struct list_head *lh;
836 
837 	spin_lock_bh(&target->rx_lock);
838 
839 	if (target->pipe.htc_packet_pool == NULL) {
840 		target->pipe.htc_packet_pool = packet;
841 		packet->list.next = NULL;
842 	} else {
843 		lh = (struct list_head *) target->pipe.htc_packet_pool;
844 		packet->list.next = lh;
845 		target->pipe.htc_packet_pool = packet;
846 	}
847 
848 	spin_unlock_bh(&target->rx_lock);
849 }
850 
851 static int htc_process_trailer(struct htc_target *target, u8 *buffer,
852 			       int len, enum htc_endpoint_id from_ep)
853 {
854 	struct htc_credit_report *report;
855 	struct htc_record_hdr *record;
856 	u8 *record_buf;
857 	int status = 0;
858 
859 	while (len > 0) {
860 		if (len < sizeof(struct htc_record_hdr)) {
861 			status = -EINVAL;
862 			break;
863 		}
864 
865 		/* these are byte aligned structs */
866 		record = (struct htc_record_hdr *) buffer;
867 		len -= sizeof(struct htc_record_hdr);
868 		buffer += sizeof(struct htc_record_hdr);
869 
870 		if (record->len > len) {
871 			/* no room left in buffer for record */
872 			ath6kl_dbg(ATH6KL_DBG_HTC,
873 				   "invalid length: %d (id:%d) buffer has: %d bytes left\n",
874 				   record->len, record->rec_id, len);
875 			status = -EINVAL;
876 			break;
877 		}
878 
879 		/* start of record follows the header */
880 		record_buf = buffer;
881 
882 		switch (record->rec_id) {
883 		case HTC_RECORD_CREDITS:
884 			if (record->len < sizeof(struct htc_credit_report)) {
885 				WARN_ON_ONCE(1);
886 				return -EINVAL;
887 			}
888 
889 			report = (struct htc_credit_report *) record_buf;
890 			htc_process_credit_report(target, report,
891 						  record->len / sizeof(*report),
892 						  from_ep);
893 			break;
894 		default:
895 			ath6kl_dbg(ATH6KL_DBG_HTC,
896 				   "unhandled record: id:%d length:%d\n",
897 				   record->rec_id, record->len);
898 			break;
899 		}
900 
901 		/* advance buffer past this record for next time around */
902 		buffer += record->len;
903 		len -= record->len;
904 	}
905 
906 	return status;
907 }
908 
909 static void do_recv_completion(struct htc_endpoint *ep,
910 			       struct list_head *queue_to_indicate)
911 {
912 	struct htc_packet *packet;
913 
914 	if (list_empty(queue_to_indicate)) {
915 		/* nothing to indicate */
916 		return;
917 	}
918 
919 	/* using legacy EpRecv */
920 	while (!list_empty(queue_to_indicate)) {
921 		packet = list_first_entry(queue_to_indicate,
922 					  struct htc_packet, list);
923 		list_del(&packet->list);
924 		ep->ep_cb.rx(ep->target, packet);
925 	}
926 
927 	return;
928 }
929 
930 static void recv_packet_completion(struct htc_target *target,
931 				   struct htc_endpoint *ep,
932 				   struct htc_packet *packet)
933 {
934 	struct list_head container;
935 	INIT_LIST_HEAD(&container);
936 	list_add_tail(&packet->list, &container);
937 
938 	/* do completion */
939 	do_recv_completion(ep, &container);
940 }
941 
942 static int ath6kl_htc_pipe_rx_complete(struct ath6kl *ar, struct sk_buff *skb,
943 				       u8 pipeid)
944 {
945 	struct htc_target *target = ar->htc_target;
946 	u8 *netdata, *trailer, hdr_info;
947 	struct htc_frame_hdr *htc_hdr;
948 	u32 netlen, trailerlen = 0;
949 	struct htc_packet *packet;
950 	struct htc_endpoint *ep;
951 	u16 payload_len;
952 	int status = 0;
953 
954 	/*
955 	 * ar->htc_target can be NULL due to a race condition that can occur
956 	 * during driver initialization(we do 'ath6kl_hif_power_on' before
957 	 * initializing 'ar->htc_target' via 'ath6kl_htc_create').
958 	 * 'ath6kl_hif_power_on' assigns 'ath6kl_recv_complete' as
959 	 * usb_complete_t/callback function for 'usb_fill_bulk_urb'.
960 	 * Thus the possibility of ar->htc_target being NULL
961 	 * via ath6kl_recv_complete -> ath6kl_usb_io_comp_work.
962 	 */
963 	if (!target) {
964 		ath6kl_dbg(ATH6KL_DBG_HTC, "Target not yet initialized\n");
965 		status = -EINVAL;
966 		goto free_skb;
967 	}
968 
969 
970 	netdata = skb->data;
971 	netlen = skb->len;
972 
973 	htc_hdr = (struct htc_frame_hdr *) netdata;
974 
975 	if (htc_hdr->eid >= ENDPOINT_MAX) {
976 		ath6kl_dbg(ATH6KL_DBG_HTC,
977 			   "HTC Rx: invalid EndpointID=%d\n",
978 			   htc_hdr->eid);
979 		status = -EINVAL;
980 		goto free_skb;
981 	}
982 	ep = &target->endpoint[htc_hdr->eid];
983 
984 	payload_len = le16_to_cpu(get_unaligned(&htc_hdr->payld_len));
985 
986 	if (netlen < (payload_len + HTC_HDR_LENGTH)) {
987 		ath6kl_dbg(ATH6KL_DBG_HTC,
988 			   "HTC Rx: insufficient length, got:%d expected =%zu\n",
989 			   netlen, payload_len + HTC_HDR_LENGTH);
990 		status = -EINVAL;
991 		goto free_skb;
992 	}
993 
994 	/* get flags to check for trailer */
995 	hdr_info = htc_hdr->flags;
996 	if (hdr_info & HTC_FLG_RX_TRAILER) {
997 		/* extract the trailer length */
998 		hdr_info = htc_hdr->ctrl[0];
999 		if ((hdr_info < sizeof(struct htc_record_hdr)) ||
1000 		    (hdr_info > payload_len)) {
1001 			ath6kl_dbg(ATH6KL_DBG_HTC,
1002 				   "invalid header: payloadlen should be %d, CB[0]: %d\n",
1003 				   payload_len, hdr_info);
1004 			status = -EINVAL;
1005 			goto free_skb;
1006 		}
1007 
1008 		trailerlen = hdr_info;
1009 		/* process trailer after hdr/apps payload */
1010 		trailer = (u8 *) htc_hdr + HTC_HDR_LENGTH +
1011 			payload_len - hdr_info;
1012 		status = htc_process_trailer(target, trailer, hdr_info,
1013 					     htc_hdr->eid);
1014 		if (status != 0)
1015 			goto free_skb;
1016 	}
1017 
1018 	if (((int) payload_len - (int) trailerlen) <= 0) {
1019 		/* zero length packet with trailer, just drop these */
1020 		goto free_skb;
1021 	}
1022 
1023 	if (htc_hdr->eid == ENDPOINT_0) {
1024 		/* handle HTC control message */
1025 		if (target->htc_flags & HTC_OP_STATE_SETUP_COMPLETE) {
1026 			/*
1027 			 * fatal: target should not send unsolicited
1028 			 * messageson the endpoint 0
1029 			 */
1030 			ath6kl_dbg(ATH6KL_DBG_HTC,
1031 				   "HTC ignores Rx Ctrl after setup complete\n");
1032 			status = -EINVAL;
1033 			goto free_skb;
1034 		}
1035 
1036 		/* remove HTC header */
1037 		skb_pull(skb, HTC_HDR_LENGTH);
1038 
1039 		netdata = skb->data;
1040 		netlen = skb->len;
1041 
1042 		spin_lock_bh(&target->rx_lock);
1043 
1044 		target->pipe.ctrl_response_valid = true;
1045 		target->pipe.ctrl_response_len = min_t(int, netlen,
1046 						       HTC_MAX_CTRL_MSG_LEN);
1047 		memcpy(target->pipe.ctrl_response_buf, netdata,
1048 		       target->pipe.ctrl_response_len);
1049 
1050 		spin_unlock_bh(&target->rx_lock);
1051 
1052 		dev_kfree_skb(skb);
1053 		skb = NULL;
1054 
1055 		goto free_skb;
1056 	}
1057 
1058 	/*
1059 	 * TODO: the message based HIF architecture allocates net bufs
1060 	 * for recv packets since it bridges that HIF to upper layers,
1061 	 * which expects HTC packets, we form the packets here
1062 	 */
1063 	packet = alloc_htc_packet_container(target);
1064 	if (packet == NULL) {
1065 		status = -ENOMEM;
1066 		goto free_skb;
1067 	}
1068 
1069 	packet->status = 0;
1070 	packet->endpoint = htc_hdr->eid;
1071 	packet->pkt_cntxt = skb;
1072 
1073 	/* TODO: for backwards compatibility */
1074 	packet->buf = skb_push(skb, 0) + HTC_HDR_LENGTH;
1075 	packet->act_len = netlen - HTC_HDR_LENGTH - trailerlen;
1076 
1077 	/*
1078 	 * TODO: this is a hack because the driver layer will set the
1079 	 * actual len of the skb again which will just double the len
1080 	 */
1081 	skb_trim(skb, 0);
1082 
1083 	recv_packet_completion(target, ep, packet);
1084 
1085 	/* recover the packet container */
1086 	free_htc_packet_container(target, packet);
1087 	skb = NULL;
1088 
1089 free_skb:
1090 	dev_kfree_skb(skb);
1091 
1092 	return status;
1093 }
1094 
1095 static void htc_flush_rx_queue(struct htc_target *target,
1096 			       struct htc_endpoint *ep)
1097 {
1098 	struct list_head container;
1099 	struct htc_packet *packet;
1100 
1101 	spin_lock_bh(&target->rx_lock);
1102 
1103 	while (1) {
1104 		if (list_empty(&ep->rx_bufq))
1105 			break;
1106 
1107 		packet = list_first_entry(&ep->rx_bufq,
1108 					  struct htc_packet, list);
1109 		list_del(&packet->list);
1110 
1111 		spin_unlock_bh(&target->rx_lock);
1112 		packet->status = -ECANCELED;
1113 		packet->act_len = 0;
1114 
1115 		ath6kl_dbg(ATH6KL_DBG_HTC,
1116 			   "Flushing RX packet:0x%p, length:%d, ep:%d\n",
1117 			   packet, packet->buf_len,
1118 			   packet->endpoint);
1119 
1120 		INIT_LIST_HEAD(&container);
1121 		list_add_tail(&packet->list, &container);
1122 
1123 		/* give the packet back */
1124 		do_recv_completion(ep, &container);
1125 		spin_lock_bh(&target->rx_lock);
1126 	}
1127 
1128 	spin_unlock_bh(&target->rx_lock);
1129 }
1130 
1131 /* polling routine to wait for a control packet to be received */
1132 static int htc_wait_recv_ctrl_message(struct htc_target *target)
1133 {
1134 	int count = HTC_TARGET_RESPONSE_POLL_COUNT;
1135 
1136 	while (count > 0) {
1137 		spin_lock_bh(&target->rx_lock);
1138 
1139 		if (target->pipe.ctrl_response_valid) {
1140 			target->pipe.ctrl_response_valid = false;
1141 			spin_unlock_bh(&target->rx_lock);
1142 			break;
1143 		}
1144 
1145 		spin_unlock_bh(&target->rx_lock);
1146 
1147 		count--;
1148 
1149 		msleep_interruptible(HTC_TARGET_RESPONSE_POLL_WAIT);
1150 	}
1151 
1152 	if (count <= 0) {
1153 		ath6kl_warn("htc pipe control receive timeout!\n");
1154 		return -ETIMEDOUT;
1155 	}
1156 
1157 	return 0;
1158 }
1159 
1160 static void htc_rxctrl_complete(struct htc_target *context,
1161 				struct htc_packet *packet)
1162 {
1163 	struct sk_buff *skb = packet->skb;
1164 
1165 	if (packet->endpoint == ENDPOINT_0 &&
1166 	    packet->status == -ECANCELED &&
1167 	    skb != NULL)
1168 		dev_kfree_skb(skb);
1169 }
1170 
1171 /* htc pipe initialization */
1172 static void reset_endpoint_states(struct htc_target *target)
1173 {
1174 	struct htc_endpoint *ep;
1175 	int i;
1176 
1177 	for (i = ENDPOINT_0; i < ENDPOINT_MAX; i++) {
1178 		ep = &target->endpoint[i];
1179 		ep->svc_id = 0;
1180 		ep->len_max = 0;
1181 		ep->max_txq_depth = 0;
1182 		ep->eid = i;
1183 		INIT_LIST_HEAD(&ep->txq);
1184 		INIT_LIST_HEAD(&ep->pipe.tx_lookup_queue);
1185 		INIT_LIST_HEAD(&ep->rx_bufq);
1186 		ep->target = target;
1187 		ep->pipe.tx_credit_flow_enabled = true;
1188 	}
1189 }
1190 
1191 /* start HTC, this is called after all services are connected */
1192 static int htc_config_target_hif_pipe(struct htc_target *target)
1193 {
1194 	return 0;
1195 }
1196 
1197 /* htc service functions */
1198 static u8 htc_get_credit_alloc(struct htc_target *target, u16 service_id)
1199 {
1200 	u8 allocation = 0;
1201 	int i;
1202 
1203 	for (i = 0; i < ENDPOINT_MAX; i++) {
1204 		if (target->pipe.txcredit_alloc[i].service_id == service_id)
1205 			allocation =
1206 				target->pipe.txcredit_alloc[i].credit_alloc;
1207 	}
1208 
1209 	if (allocation == 0) {
1210 		ath6kl_dbg(ATH6KL_DBG_HTC,
1211 			   "HTC Service TX : 0x%2.2X : allocation is zero!\n",
1212 			   service_id);
1213 	}
1214 
1215 	return allocation;
1216 }
1217 
1218 static int ath6kl_htc_pipe_conn_service(struct htc_target *target,
1219 		     struct htc_service_connect_req *conn_req,
1220 		     struct htc_service_connect_resp *conn_resp)
1221 {
1222 	struct ath6kl *ar = target->dev->ar;
1223 	struct htc_packet *packet = NULL;
1224 	struct htc_conn_service_resp *resp_msg;
1225 	struct htc_conn_service_msg *conn_msg;
1226 	enum htc_endpoint_id assigned_epid = ENDPOINT_MAX;
1227 	bool disable_credit_flowctrl = false;
1228 	unsigned int max_msg_size = 0;
1229 	struct htc_endpoint *ep;
1230 	int length, status = 0;
1231 	struct sk_buff *skb;
1232 	u8 tx_alloc;
1233 	u16 flags;
1234 
1235 	if (conn_req->svc_id == 0) {
1236 		WARN_ON_ONCE(1);
1237 		status = -EINVAL;
1238 		goto free_packet;
1239 	}
1240 
1241 	if (conn_req->svc_id == HTC_CTRL_RSVD_SVC) {
1242 		/* special case for pseudo control service */
1243 		assigned_epid = ENDPOINT_0;
1244 		max_msg_size = HTC_MAX_CTRL_MSG_LEN;
1245 		tx_alloc = 0;
1246 
1247 	} else {
1248 		tx_alloc = htc_get_credit_alloc(target, conn_req->svc_id);
1249 		if (tx_alloc == 0) {
1250 			status = -ENOMEM;
1251 			goto free_packet;
1252 		}
1253 
1254 		/* allocate a packet to send to the target */
1255 		packet = htc_alloc_txctrl_packet(target);
1256 
1257 		if (packet == NULL) {
1258 			WARN_ON_ONCE(1);
1259 			status = -ENOMEM;
1260 			goto free_packet;
1261 		}
1262 
1263 		skb = packet->skb;
1264 		length = sizeof(struct htc_conn_service_msg);
1265 
1266 		/* assemble connect service message */
1267 		conn_msg = skb_put(skb, length);
1268 		if (conn_msg == NULL) {
1269 			WARN_ON_ONCE(1);
1270 			status = -EINVAL;
1271 			goto free_packet;
1272 		}
1273 
1274 		memset(conn_msg, 0,
1275 		       sizeof(struct htc_conn_service_msg));
1276 		conn_msg->msg_id = cpu_to_le16(HTC_MSG_CONN_SVC_ID);
1277 		conn_msg->svc_id = cpu_to_le16(conn_req->svc_id);
1278 		conn_msg->conn_flags = cpu_to_le16(conn_req->conn_flags &
1279 					~HTC_CONN_FLGS_SET_RECV_ALLOC_MASK);
1280 
1281 		/* tell target desired recv alloc for this ep */
1282 		flags = tx_alloc << HTC_CONN_FLGS_SET_RECV_ALLOC_SHIFT;
1283 		conn_msg->conn_flags |= cpu_to_le16(flags);
1284 
1285 		if (conn_req->conn_flags &
1286 		    HTC_CONN_FLGS_DISABLE_CRED_FLOW_CTRL) {
1287 			disable_credit_flowctrl = true;
1288 		}
1289 
1290 		set_htc_pkt_info(packet, NULL, (u8 *) conn_msg,
1291 				 length,
1292 				 ENDPOINT_0, HTC_SERVICE_TX_PACKET_TAG);
1293 
1294 		status = ath6kl_htc_pipe_tx(target, packet);
1295 
1296 		/* we don't own it anymore */
1297 		packet = NULL;
1298 		if (status != 0)
1299 			goto free_packet;
1300 
1301 		/* wait for response */
1302 		status = htc_wait_recv_ctrl_message(target);
1303 		if (status != 0)
1304 			goto free_packet;
1305 
1306 		/* we controlled the buffer creation so it has to be
1307 		 * properly aligned
1308 		 */
1309 		resp_msg = (struct htc_conn_service_resp *)
1310 		    target->pipe.ctrl_response_buf;
1311 
1312 		if (resp_msg->msg_id != cpu_to_le16(HTC_MSG_CONN_SVC_RESP_ID) ||
1313 		    (target->pipe.ctrl_response_len < sizeof(*resp_msg))) {
1314 			/* this message is not valid */
1315 			WARN_ON_ONCE(1);
1316 			status = -EINVAL;
1317 			goto free_packet;
1318 		}
1319 
1320 		ath6kl_dbg(ATH6KL_DBG_TRC,
1321 			   "%s: service 0x%X conn resp: status: %d ep: %d\n",
1322 			   __func__, resp_msg->svc_id, resp_msg->status,
1323 			   resp_msg->eid);
1324 
1325 		conn_resp->resp_code = resp_msg->status;
1326 		/* check response status */
1327 		if (resp_msg->status != HTC_SERVICE_SUCCESS) {
1328 			ath6kl_dbg(ATH6KL_DBG_HTC,
1329 				   "Target failed service 0x%X connect request (status:%d)\n",
1330 				   resp_msg->svc_id, resp_msg->status);
1331 			status = -EINVAL;
1332 			goto free_packet;
1333 		}
1334 
1335 		assigned_epid = (enum htc_endpoint_id) resp_msg->eid;
1336 		max_msg_size = le16_to_cpu(resp_msg->max_msg_sz);
1337 	}
1338 
1339 	/* the rest are parameter checks so set the error status */
1340 	status = -EINVAL;
1341 
1342 	if (assigned_epid >= ENDPOINT_MAX) {
1343 		WARN_ON_ONCE(1);
1344 		goto free_packet;
1345 	}
1346 
1347 	if (max_msg_size == 0) {
1348 		WARN_ON_ONCE(1);
1349 		goto free_packet;
1350 	}
1351 
1352 	ep = &target->endpoint[assigned_epid];
1353 	ep->eid = assigned_epid;
1354 	if (ep->svc_id != 0) {
1355 		/* endpoint already in use! */
1356 		WARN_ON_ONCE(1);
1357 		goto free_packet;
1358 	}
1359 
1360 	/* return assigned endpoint to caller */
1361 	conn_resp->endpoint = assigned_epid;
1362 	conn_resp->len_max = max_msg_size;
1363 
1364 	/* setup the endpoint */
1365 	ep->svc_id = conn_req->svc_id; /* this marks ep in use */
1366 	ep->max_txq_depth = conn_req->max_txq_depth;
1367 	ep->len_max = max_msg_size;
1368 	ep->cred_dist.credits = tx_alloc;
1369 	ep->cred_dist.cred_sz = target->tgt_cred_sz;
1370 	ep->cred_dist.cred_per_msg = max_msg_size / target->tgt_cred_sz;
1371 	if (max_msg_size % target->tgt_cred_sz)
1372 		ep->cred_dist.cred_per_msg++;
1373 
1374 	/* copy all the callbacks */
1375 	ep->ep_cb = conn_req->ep_cb;
1376 
1377 	/* initialize tx_drop_packet_threshold */
1378 	ep->tx_drop_packet_threshold = MAX_HI_COOKIE_NUM;
1379 
1380 	status = ath6kl_hif_pipe_map_service(ar, ep->svc_id,
1381 					     &ep->pipe.pipeid_ul,
1382 					     &ep->pipe.pipeid_dl);
1383 	if (status != 0)
1384 		goto free_packet;
1385 
1386 	ath6kl_dbg(ATH6KL_DBG_HTC,
1387 		   "SVC Ready: 0x%4.4X: ULpipe:%d DLpipe:%d id:%d\n",
1388 		   ep->svc_id, ep->pipe.pipeid_ul,
1389 		   ep->pipe.pipeid_dl, ep->eid);
1390 
1391 	if (disable_credit_flowctrl && ep->pipe.tx_credit_flow_enabled) {
1392 		ep->pipe.tx_credit_flow_enabled = false;
1393 		ath6kl_dbg(ATH6KL_DBG_HTC,
1394 			   "SVC: 0x%4.4X ep:%d TX flow control off\n",
1395 			   ep->svc_id, assigned_epid);
1396 	}
1397 
1398 free_packet:
1399 	if (packet != NULL)
1400 		htc_free_txctrl_packet(target, packet);
1401 	return status;
1402 }
1403 
1404 /* htc export functions */
1405 static void *ath6kl_htc_pipe_create(struct ath6kl *ar)
1406 {
1407 	int status = 0;
1408 	struct htc_endpoint *ep = NULL;
1409 	struct htc_target *target = NULL;
1410 	struct htc_packet *packet;
1411 	int i;
1412 
1413 	target = kzalloc(sizeof(struct htc_target), GFP_KERNEL);
1414 	if (target == NULL) {
1415 		ath6kl_err("htc create unable to allocate memory\n");
1416 		status = -ENOMEM;
1417 		goto fail_htc_create;
1418 	}
1419 
1420 	spin_lock_init(&target->htc_lock);
1421 	spin_lock_init(&target->rx_lock);
1422 	spin_lock_init(&target->tx_lock);
1423 
1424 	reset_endpoint_states(target);
1425 
1426 	for (i = 0; i < HTC_PACKET_CONTAINER_ALLOCATION; i++) {
1427 		packet = kzalloc(sizeof(struct htc_packet), GFP_KERNEL);
1428 
1429 		if (packet != NULL)
1430 			free_htc_packet_container(target, packet);
1431 	}
1432 
1433 	target->dev = kzalloc(sizeof(*target->dev), GFP_KERNEL);
1434 	if (!target->dev) {
1435 		ath6kl_err("unable to allocate memory\n");
1436 		status = -ENOMEM;
1437 		goto fail_htc_create;
1438 	}
1439 	target->dev->ar = ar;
1440 	target->dev->htc_cnxt = target;
1441 
1442 	/* Get HIF default pipe for HTC message exchange */
1443 	ep = &target->endpoint[ENDPOINT_0];
1444 
1445 	ath6kl_hif_pipe_get_default(ar, &ep->pipe.pipeid_ul,
1446 				    &ep->pipe.pipeid_dl);
1447 
1448 	return target;
1449 
1450 fail_htc_create:
1451 	if (status != 0) {
1452 		if (target != NULL)
1453 			ath6kl_htc_pipe_cleanup(target);
1454 
1455 		target = NULL;
1456 	}
1457 	return target;
1458 }
1459 
1460 /* cleanup the HTC instance */
1461 static void ath6kl_htc_pipe_cleanup(struct htc_target *target)
1462 {
1463 	struct htc_packet *packet;
1464 
1465 	while (true) {
1466 		packet = alloc_htc_packet_container(target);
1467 		if (packet == NULL)
1468 			break;
1469 		kfree(packet);
1470 	}
1471 
1472 	kfree(target->dev);
1473 
1474 	/* kfree our instance */
1475 	kfree(target);
1476 }
1477 
1478 static int ath6kl_htc_pipe_start(struct htc_target *target)
1479 {
1480 	struct sk_buff *skb;
1481 	struct htc_setup_comp_ext_msg *setup;
1482 	struct htc_packet *packet;
1483 
1484 	htc_config_target_hif_pipe(target);
1485 
1486 	/* allocate a buffer to send */
1487 	packet = htc_alloc_txctrl_packet(target);
1488 	if (packet == NULL) {
1489 		WARN_ON_ONCE(1);
1490 		return -ENOMEM;
1491 	}
1492 
1493 	skb = packet->skb;
1494 
1495 	/* assemble setup complete message */
1496 	setup = skb_put(skb, sizeof(*setup));
1497 	memset(setup, 0, sizeof(struct htc_setup_comp_ext_msg));
1498 	setup->msg_id = cpu_to_le16(HTC_MSG_SETUP_COMPLETE_EX_ID);
1499 
1500 	ath6kl_dbg(ATH6KL_DBG_HTC, "HTC using TX credit flow control\n");
1501 
1502 	set_htc_pkt_info(packet, NULL, (u8 *) setup,
1503 			 sizeof(struct htc_setup_comp_ext_msg),
1504 			 ENDPOINT_0, HTC_SERVICE_TX_PACKET_TAG);
1505 
1506 	target->htc_flags |= HTC_OP_STATE_SETUP_COMPLETE;
1507 
1508 	return ath6kl_htc_pipe_tx(target, packet);
1509 }
1510 
1511 static void ath6kl_htc_pipe_stop(struct htc_target *target)
1512 {
1513 	int i;
1514 	struct htc_endpoint *ep;
1515 
1516 	/* cleanup endpoints */
1517 	for (i = 0; i < ENDPOINT_MAX; i++) {
1518 		ep = &target->endpoint[i];
1519 		htc_flush_rx_queue(target, ep);
1520 		htc_flush_tx_endpoint(target, ep, HTC_TX_PACKET_TAG_ALL);
1521 	}
1522 
1523 	reset_endpoint_states(target);
1524 	target->htc_flags &= ~HTC_OP_STATE_SETUP_COMPLETE;
1525 }
1526 
1527 static int ath6kl_htc_pipe_get_rxbuf_num(struct htc_target *target,
1528 					 enum htc_endpoint_id endpoint)
1529 {
1530 	int num;
1531 
1532 	spin_lock_bh(&target->rx_lock);
1533 	num = get_queue_depth(&(target->endpoint[endpoint].rx_bufq));
1534 	spin_unlock_bh(&target->rx_lock);
1535 
1536 	return num;
1537 }
1538 
1539 static int ath6kl_htc_pipe_tx(struct htc_target *target,
1540 			      struct htc_packet *packet)
1541 {
1542 	struct list_head queue;
1543 
1544 	ath6kl_dbg(ATH6KL_DBG_HTC,
1545 		   "%s: endPointId: %d, buffer: 0x%p, length: %d\n",
1546 		   __func__, packet->endpoint, packet->buf,
1547 		   packet->act_len);
1548 
1549 	INIT_LIST_HEAD(&queue);
1550 	list_add_tail(&packet->list, &queue);
1551 
1552 	return htc_send_packets_multiple(target, &queue);
1553 }
1554 
1555 static int ath6kl_htc_pipe_wait_target(struct htc_target *target)
1556 {
1557 	struct htc_ready_ext_msg *ready_msg;
1558 	struct htc_service_connect_req connect;
1559 	struct htc_service_connect_resp resp;
1560 	int status = 0;
1561 
1562 	status = htc_wait_recv_ctrl_message(target);
1563 
1564 	if (status != 0)
1565 		return status;
1566 
1567 	if (target->pipe.ctrl_response_len < sizeof(*ready_msg)) {
1568 		ath6kl_warn("invalid htc pipe ready msg len: %d\n",
1569 			    target->pipe.ctrl_response_len);
1570 		return -ECOMM;
1571 	}
1572 
1573 	ready_msg = (struct htc_ready_ext_msg *) target->pipe.ctrl_response_buf;
1574 
1575 	if (ready_msg->ver2_0_info.msg_id != cpu_to_le16(HTC_MSG_READY_ID)) {
1576 		ath6kl_warn("invalid htc pipe ready msg: 0x%x\n",
1577 			    ready_msg->ver2_0_info.msg_id);
1578 		return -ECOMM;
1579 	}
1580 
1581 	ath6kl_dbg(ATH6KL_DBG_HTC,
1582 		   "Target Ready! : transmit resources : %d size:%d\n",
1583 		   ready_msg->ver2_0_info.cred_cnt,
1584 		   ready_msg->ver2_0_info.cred_sz);
1585 
1586 	target->tgt_creds = le16_to_cpu(ready_msg->ver2_0_info.cred_cnt);
1587 	target->tgt_cred_sz = le16_to_cpu(ready_msg->ver2_0_info.cred_sz);
1588 
1589 	if ((target->tgt_creds == 0) || (target->tgt_cred_sz == 0))
1590 		return -ECOMM;
1591 
1592 	htc_setup_target_buffer_assignments(target);
1593 
1594 	/* setup our pseudo HTC control endpoint connection */
1595 	memset(&connect, 0, sizeof(connect));
1596 	memset(&resp, 0, sizeof(resp));
1597 	connect.ep_cb.tx_complete = htc_txctrl_complete;
1598 	connect.ep_cb.rx = htc_rxctrl_complete;
1599 	connect.max_txq_depth = NUM_CONTROL_TX_BUFFERS;
1600 	connect.svc_id = HTC_CTRL_RSVD_SVC;
1601 
1602 	/* connect fake service */
1603 	status = ath6kl_htc_pipe_conn_service(target, &connect, &resp);
1604 
1605 	return status;
1606 }
1607 
1608 static void ath6kl_htc_pipe_flush_txep(struct htc_target *target,
1609 				       enum htc_endpoint_id endpoint, u16 tag)
1610 {
1611 	struct htc_endpoint *ep = &target->endpoint[endpoint];
1612 
1613 	if (ep->svc_id == 0) {
1614 		WARN_ON_ONCE(1);
1615 		/* not in use.. */
1616 		return;
1617 	}
1618 
1619 	htc_flush_tx_endpoint(target, ep, tag);
1620 }
1621 
1622 static int ath6kl_htc_pipe_add_rxbuf_multiple(struct htc_target *target,
1623 					      struct list_head *pkt_queue)
1624 {
1625 	struct htc_packet *packet, *tmp_pkt, *first;
1626 	struct htc_endpoint *ep;
1627 	int status = 0;
1628 
1629 	if (list_empty(pkt_queue))
1630 		return -EINVAL;
1631 
1632 	first = list_first_entry(pkt_queue, struct htc_packet, list);
1633 
1634 	if (first->endpoint >= ENDPOINT_MAX) {
1635 		WARN_ON_ONCE(1);
1636 		return -EINVAL;
1637 	}
1638 
1639 	ath6kl_dbg(ATH6KL_DBG_HTC, "%s: epid: %d, cnt:%d, len: %d\n",
1640 		   __func__, first->endpoint, get_queue_depth(pkt_queue),
1641 		   first->buf_len);
1642 
1643 	ep = &target->endpoint[first->endpoint];
1644 
1645 	spin_lock_bh(&target->rx_lock);
1646 
1647 	/* store receive packets */
1648 	list_splice_tail_init(pkt_queue, &ep->rx_bufq);
1649 
1650 	spin_unlock_bh(&target->rx_lock);
1651 
1652 	if (status != 0) {
1653 		/* walk through queue and mark each one canceled */
1654 		list_for_each_entry_safe(packet, tmp_pkt, pkt_queue, list) {
1655 			packet->status = -ECANCELED;
1656 		}
1657 
1658 		do_recv_completion(ep, pkt_queue);
1659 	}
1660 
1661 	return status;
1662 }
1663 
1664 static void ath6kl_htc_pipe_activity_changed(struct htc_target *target,
1665 					     enum htc_endpoint_id ep,
1666 					     bool active)
1667 {
1668 	/* TODO */
1669 }
1670 
1671 static void ath6kl_htc_pipe_flush_rx_buf(struct htc_target *target)
1672 {
1673 	struct htc_endpoint *endpoint;
1674 	struct htc_packet *packet, *tmp_pkt;
1675 	int i;
1676 
1677 	for (i = ENDPOINT_0; i < ENDPOINT_MAX; i++) {
1678 		endpoint = &target->endpoint[i];
1679 
1680 		spin_lock_bh(&target->rx_lock);
1681 
1682 		list_for_each_entry_safe(packet, tmp_pkt,
1683 					 &endpoint->rx_bufq, list) {
1684 			list_del(&packet->list);
1685 			spin_unlock_bh(&target->rx_lock);
1686 			ath6kl_dbg(ATH6KL_DBG_HTC,
1687 				   "htc rx flush pkt 0x%p len %d ep %d\n",
1688 				   packet, packet->buf_len,
1689 				   packet->endpoint);
1690 			dev_kfree_skb(packet->pkt_cntxt);
1691 			spin_lock_bh(&target->rx_lock);
1692 		}
1693 
1694 		spin_unlock_bh(&target->rx_lock);
1695 	}
1696 }
1697 
1698 static int ath6kl_htc_pipe_credit_setup(struct htc_target *target,
1699 					struct ath6kl_htc_credit_info *info)
1700 {
1701 	return 0;
1702 }
1703 
1704 static const struct ath6kl_htc_ops ath6kl_htc_pipe_ops = {
1705 	.create = ath6kl_htc_pipe_create,
1706 	.wait_target = ath6kl_htc_pipe_wait_target,
1707 	.start = ath6kl_htc_pipe_start,
1708 	.conn_service = ath6kl_htc_pipe_conn_service,
1709 	.tx = ath6kl_htc_pipe_tx,
1710 	.stop = ath6kl_htc_pipe_stop,
1711 	.cleanup = ath6kl_htc_pipe_cleanup,
1712 	.flush_txep = ath6kl_htc_pipe_flush_txep,
1713 	.flush_rx_buf = ath6kl_htc_pipe_flush_rx_buf,
1714 	.activity_changed = ath6kl_htc_pipe_activity_changed,
1715 	.get_rxbuf_num = ath6kl_htc_pipe_get_rxbuf_num,
1716 	.add_rxbuf_multiple = ath6kl_htc_pipe_add_rxbuf_multiple,
1717 	.credit_setup = ath6kl_htc_pipe_credit_setup,
1718 	.tx_complete = ath6kl_htc_pipe_tx_complete,
1719 	.rx_complete = ath6kl_htc_pipe_rx_complete,
1720 };
1721 
1722 void ath6kl_htc_pipe_attach(struct ath6kl *ar)
1723 {
1724 	ar->htc_ops = &ath6kl_htc_pipe_ops;
1725 }
1726