xref: /openbmc/linux/drivers/net/wireless/ath/ath9k/recv.c (revision 9c1f8594)
1 /*
2  * Copyright (c) 2008-2011 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 <linux/dma-mapping.h>
18 #include "ath9k.h"
19 #include "ar9003_mac.h"
20 
21 #define SKB_CB_ATHBUF(__skb)	(*((struct ath_buf **)__skb->cb))
22 
23 static inline bool ath_is_alt_ant_ratio_better(int alt_ratio, int maxdelta,
24 					       int mindelta, int main_rssi_avg,
25 					       int alt_rssi_avg, int pkt_count)
26 {
27 	return (((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
28 		(alt_rssi_avg > main_rssi_avg + maxdelta)) ||
29 		(alt_rssi_avg > main_rssi_avg + mindelta)) && (pkt_count > 50);
30 }
31 
32 static inline bool ath_ant_div_comb_alt_check(u8 div_group, int alt_ratio,
33 					int curr_main_set, int curr_alt_set,
34 					int alt_rssi_avg, int main_rssi_avg)
35 {
36 	bool result = false;
37 	switch (div_group) {
38 	case 0:
39 		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO)
40 			result = true;
41 		break;
42 	case 1:
43 	case 2:
44 		if ((((curr_main_set == ATH_ANT_DIV_COMB_LNA2) &&
45 			(curr_alt_set == ATH_ANT_DIV_COMB_LNA1) &&
46 				(alt_rssi_avg >= (main_rssi_avg - 5))) ||
47 			((curr_main_set == ATH_ANT_DIV_COMB_LNA1) &&
48 			(curr_alt_set == ATH_ANT_DIV_COMB_LNA2) &&
49 				(alt_rssi_avg >= (main_rssi_avg - 2)))) &&
50 							(alt_rssi_avg >= 4))
51 			result = true;
52 		else
53 			result = false;
54 		break;
55 	}
56 
57 	return result;
58 }
59 
60 static inline bool ath9k_check_auto_sleep(struct ath_softc *sc)
61 {
62 	return sc->ps_enabled &&
63 	       (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP);
64 }
65 
66 /*
67  * Setup and link descriptors.
68  *
69  * 11N: we can no longer afford to self link the last descriptor.
70  * MAC acknowledges BA status as long as it copies frames to host
71  * buffer (or rx fifo). This can incorrectly acknowledge packets
72  * to a sender if last desc is self-linked.
73  */
74 static void ath_rx_buf_link(struct ath_softc *sc, struct ath_buf *bf)
75 {
76 	struct ath_hw *ah = sc->sc_ah;
77 	struct ath_common *common = ath9k_hw_common(ah);
78 	struct ath_desc *ds;
79 	struct sk_buff *skb;
80 
81 	ATH_RXBUF_RESET(bf);
82 
83 	ds = bf->bf_desc;
84 	ds->ds_link = 0; /* link to null */
85 	ds->ds_data = bf->bf_buf_addr;
86 
87 	/* virtual addr of the beginning of the buffer. */
88 	skb = bf->bf_mpdu;
89 	BUG_ON(skb == NULL);
90 	ds->ds_vdata = skb->data;
91 
92 	/*
93 	 * setup rx descriptors. The rx_bufsize here tells the hardware
94 	 * how much data it can DMA to us and that we are prepared
95 	 * to process
96 	 */
97 	ath9k_hw_setuprxdesc(ah, ds,
98 			     common->rx_bufsize,
99 			     0);
100 
101 	if (sc->rx.rxlink == NULL)
102 		ath9k_hw_putrxbuf(ah, bf->bf_daddr);
103 	else
104 		*sc->rx.rxlink = bf->bf_daddr;
105 
106 	sc->rx.rxlink = &ds->ds_link;
107 }
108 
109 static void ath_setdefantenna(struct ath_softc *sc, u32 antenna)
110 {
111 	/* XXX block beacon interrupts */
112 	ath9k_hw_setantenna(sc->sc_ah, antenna);
113 	sc->rx.defant = antenna;
114 	sc->rx.rxotherant = 0;
115 }
116 
117 static void ath_opmode_init(struct ath_softc *sc)
118 {
119 	struct ath_hw *ah = sc->sc_ah;
120 	struct ath_common *common = ath9k_hw_common(ah);
121 
122 	u32 rfilt, mfilt[2];
123 
124 	/* configure rx filter */
125 	rfilt = ath_calcrxfilter(sc);
126 	ath9k_hw_setrxfilter(ah, rfilt);
127 
128 	/* configure bssid mask */
129 	ath_hw_setbssidmask(common);
130 
131 	/* configure operational mode */
132 	ath9k_hw_setopmode(ah);
133 
134 	/* calculate and install multicast filter */
135 	mfilt[0] = mfilt[1] = ~0;
136 	ath9k_hw_setmcastfilter(ah, mfilt[0], mfilt[1]);
137 }
138 
139 static bool ath_rx_edma_buf_link(struct ath_softc *sc,
140 				 enum ath9k_rx_qtype qtype)
141 {
142 	struct ath_hw *ah = sc->sc_ah;
143 	struct ath_rx_edma *rx_edma;
144 	struct sk_buff *skb;
145 	struct ath_buf *bf;
146 
147 	rx_edma = &sc->rx.rx_edma[qtype];
148 	if (skb_queue_len(&rx_edma->rx_fifo) >= rx_edma->rx_fifo_hwsize)
149 		return false;
150 
151 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
152 	list_del_init(&bf->list);
153 
154 	skb = bf->bf_mpdu;
155 
156 	ATH_RXBUF_RESET(bf);
157 	memset(skb->data, 0, ah->caps.rx_status_len);
158 	dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
159 				ah->caps.rx_status_len, DMA_TO_DEVICE);
160 
161 	SKB_CB_ATHBUF(skb) = bf;
162 	ath9k_hw_addrxbuf_edma(ah, bf->bf_buf_addr, qtype);
163 	skb_queue_tail(&rx_edma->rx_fifo, skb);
164 
165 	return true;
166 }
167 
168 static void ath_rx_addbuffer_edma(struct ath_softc *sc,
169 				  enum ath9k_rx_qtype qtype, int size)
170 {
171 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
172 	u32 nbuf = 0;
173 
174 	if (list_empty(&sc->rx.rxbuf)) {
175 		ath_dbg(common, ATH_DBG_QUEUE, "No free rx buf available\n");
176 		return;
177 	}
178 
179 	while (!list_empty(&sc->rx.rxbuf)) {
180 		nbuf++;
181 
182 		if (!ath_rx_edma_buf_link(sc, qtype))
183 			break;
184 
185 		if (nbuf >= size)
186 			break;
187 	}
188 }
189 
190 static void ath_rx_remove_buffer(struct ath_softc *sc,
191 				 enum ath9k_rx_qtype qtype)
192 {
193 	struct ath_buf *bf;
194 	struct ath_rx_edma *rx_edma;
195 	struct sk_buff *skb;
196 
197 	rx_edma = &sc->rx.rx_edma[qtype];
198 
199 	while ((skb = skb_dequeue(&rx_edma->rx_fifo)) != NULL) {
200 		bf = SKB_CB_ATHBUF(skb);
201 		BUG_ON(!bf);
202 		list_add_tail(&bf->list, &sc->rx.rxbuf);
203 	}
204 }
205 
206 static void ath_rx_edma_cleanup(struct ath_softc *sc)
207 {
208 	struct ath_buf *bf;
209 
210 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP);
211 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP);
212 
213 	list_for_each_entry(bf, &sc->rx.rxbuf, list) {
214 		if (bf->bf_mpdu)
215 			dev_kfree_skb_any(bf->bf_mpdu);
216 	}
217 
218 	INIT_LIST_HEAD(&sc->rx.rxbuf);
219 
220 	kfree(sc->rx.rx_bufptr);
221 	sc->rx.rx_bufptr = NULL;
222 }
223 
224 static void ath_rx_edma_init_queue(struct ath_rx_edma *rx_edma, int size)
225 {
226 	skb_queue_head_init(&rx_edma->rx_fifo);
227 	skb_queue_head_init(&rx_edma->rx_buffers);
228 	rx_edma->rx_fifo_hwsize = size;
229 }
230 
231 static int ath_rx_edma_init(struct ath_softc *sc, int nbufs)
232 {
233 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
234 	struct ath_hw *ah = sc->sc_ah;
235 	struct sk_buff *skb;
236 	struct ath_buf *bf;
237 	int error = 0, i;
238 	u32 size;
239 
240 	ath9k_hw_set_rx_bufsize(ah, common->rx_bufsize -
241 				    ah->caps.rx_status_len);
242 
243 	ath_rx_edma_init_queue(&sc->rx.rx_edma[ATH9K_RX_QUEUE_LP],
244 			       ah->caps.rx_lp_qdepth);
245 	ath_rx_edma_init_queue(&sc->rx.rx_edma[ATH9K_RX_QUEUE_HP],
246 			       ah->caps.rx_hp_qdepth);
247 
248 	size = sizeof(struct ath_buf) * nbufs;
249 	bf = kzalloc(size, GFP_KERNEL);
250 	if (!bf)
251 		return -ENOMEM;
252 
253 	INIT_LIST_HEAD(&sc->rx.rxbuf);
254 	sc->rx.rx_bufptr = bf;
255 
256 	for (i = 0; i < nbufs; i++, bf++) {
257 		skb = ath_rxbuf_alloc(common, common->rx_bufsize, GFP_KERNEL);
258 		if (!skb) {
259 			error = -ENOMEM;
260 			goto rx_init_fail;
261 		}
262 
263 		memset(skb->data, 0, common->rx_bufsize);
264 		bf->bf_mpdu = skb;
265 
266 		bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
267 						 common->rx_bufsize,
268 						 DMA_BIDIRECTIONAL);
269 		if (unlikely(dma_mapping_error(sc->dev,
270 						bf->bf_buf_addr))) {
271 				dev_kfree_skb_any(skb);
272 				bf->bf_mpdu = NULL;
273 				bf->bf_buf_addr = 0;
274 				ath_err(common,
275 					"dma_mapping_error() on RX init\n");
276 				error = -ENOMEM;
277 				goto rx_init_fail;
278 		}
279 
280 		list_add_tail(&bf->list, &sc->rx.rxbuf);
281 	}
282 
283 	return 0;
284 
285 rx_init_fail:
286 	ath_rx_edma_cleanup(sc);
287 	return error;
288 }
289 
290 static void ath_edma_start_recv(struct ath_softc *sc)
291 {
292 	spin_lock_bh(&sc->rx.rxbuflock);
293 
294 	ath9k_hw_rxena(sc->sc_ah);
295 
296 	ath_rx_addbuffer_edma(sc, ATH9K_RX_QUEUE_HP,
297 			      sc->rx.rx_edma[ATH9K_RX_QUEUE_HP].rx_fifo_hwsize);
298 
299 	ath_rx_addbuffer_edma(sc, ATH9K_RX_QUEUE_LP,
300 			      sc->rx.rx_edma[ATH9K_RX_QUEUE_LP].rx_fifo_hwsize);
301 
302 	ath_opmode_init(sc);
303 
304 	ath9k_hw_startpcureceive(sc->sc_ah, (sc->sc_flags & SC_OP_OFFCHANNEL));
305 
306 	spin_unlock_bh(&sc->rx.rxbuflock);
307 }
308 
309 static void ath_edma_stop_recv(struct ath_softc *sc)
310 {
311 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP);
312 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP);
313 }
314 
315 int ath_rx_init(struct ath_softc *sc, int nbufs)
316 {
317 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
318 	struct sk_buff *skb;
319 	struct ath_buf *bf;
320 	int error = 0;
321 
322 	spin_lock_init(&sc->sc_pcu_lock);
323 	sc->sc_flags &= ~SC_OP_RXFLUSH;
324 	spin_lock_init(&sc->rx.rxbuflock);
325 
326 	common->rx_bufsize = IEEE80211_MAX_MPDU_LEN / 2 +
327 			     sc->sc_ah->caps.rx_status_len;
328 
329 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
330 		return ath_rx_edma_init(sc, nbufs);
331 	} else {
332 		ath_dbg(common, ATH_DBG_CONFIG, "cachelsz %u rxbufsize %u\n",
333 			common->cachelsz, common->rx_bufsize);
334 
335 		/* Initialize rx descriptors */
336 
337 		error = ath_descdma_setup(sc, &sc->rx.rxdma, &sc->rx.rxbuf,
338 				"rx", nbufs, 1, 0);
339 		if (error != 0) {
340 			ath_err(common,
341 				"failed to allocate rx descriptors: %d\n",
342 				error);
343 			goto err;
344 		}
345 
346 		list_for_each_entry(bf, &sc->rx.rxbuf, list) {
347 			skb = ath_rxbuf_alloc(common, common->rx_bufsize,
348 					      GFP_KERNEL);
349 			if (skb == NULL) {
350 				error = -ENOMEM;
351 				goto err;
352 			}
353 
354 			bf->bf_mpdu = skb;
355 			bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
356 					common->rx_bufsize,
357 					DMA_FROM_DEVICE);
358 			if (unlikely(dma_mapping_error(sc->dev,
359 							bf->bf_buf_addr))) {
360 				dev_kfree_skb_any(skb);
361 				bf->bf_mpdu = NULL;
362 				bf->bf_buf_addr = 0;
363 				ath_err(common,
364 					"dma_mapping_error() on RX init\n");
365 				error = -ENOMEM;
366 				goto err;
367 			}
368 		}
369 		sc->rx.rxlink = NULL;
370 	}
371 
372 err:
373 	if (error)
374 		ath_rx_cleanup(sc);
375 
376 	return error;
377 }
378 
379 void ath_rx_cleanup(struct ath_softc *sc)
380 {
381 	struct ath_hw *ah = sc->sc_ah;
382 	struct ath_common *common = ath9k_hw_common(ah);
383 	struct sk_buff *skb;
384 	struct ath_buf *bf;
385 
386 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
387 		ath_rx_edma_cleanup(sc);
388 		return;
389 	} else {
390 		list_for_each_entry(bf, &sc->rx.rxbuf, list) {
391 			skb = bf->bf_mpdu;
392 			if (skb) {
393 				dma_unmap_single(sc->dev, bf->bf_buf_addr,
394 						common->rx_bufsize,
395 						DMA_FROM_DEVICE);
396 				dev_kfree_skb(skb);
397 				bf->bf_buf_addr = 0;
398 				bf->bf_mpdu = NULL;
399 			}
400 		}
401 
402 		if (sc->rx.rxdma.dd_desc_len != 0)
403 			ath_descdma_cleanup(sc, &sc->rx.rxdma, &sc->rx.rxbuf);
404 	}
405 }
406 
407 /*
408  * Calculate the receive filter according to the
409  * operating mode and state:
410  *
411  * o always accept unicast, broadcast, and multicast traffic
412  * o maintain current state of phy error reception (the hal
413  *   may enable phy error frames for noise immunity work)
414  * o probe request frames are accepted only when operating in
415  *   hostap, adhoc, or monitor modes
416  * o enable promiscuous mode according to the interface state
417  * o accept beacons:
418  *   - when operating in adhoc mode so the 802.11 layer creates
419  *     node table entries for peers,
420  *   - when operating in station mode for collecting rssi data when
421  *     the station is otherwise quiet, or
422  *   - when operating as a repeater so we see repeater-sta beacons
423  *   - when scanning
424  */
425 
426 u32 ath_calcrxfilter(struct ath_softc *sc)
427 {
428 #define	RX_FILTER_PRESERVE (ATH9K_RX_FILTER_PHYERR | ATH9K_RX_FILTER_PHYRADAR)
429 
430 	u32 rfilt;
431 
432 	rfilt = (ath9k_hw_getrxfilter(sc->sc_ah) & RX_FILTER_PRESERVE)
433 		| ATH9K_RX_FILTER_UCAST | ATH9K_RX_FILTER_BCAST
434 		| ATH9K_RX_FILTER_MCAST;
435 
436 	if (sc->rx.rxfilter & FIF_PROBE_REQ)
437 		rfilt |= ATH9K_RX_FILTER_PROBEREQ;
438 
439 	/*
440 	 * Set promiscuous mode when FIF_PROMISC_IN_BSS is enabled for station
441 	 * mode interface or when in monitor mode. AP mode does not need this
442 	 * since it receives all in-BSS frames anyway.
443 	 */
444 	if (sc->sc_ah->is_monitoring)
445 		rfilt |= ATH9K_RX_FILTER_PROM;
446 
447 	if (sc->rx.rxfilter & FIF_CONTROL)
448 		rfilt |= ATH9K_RX_FILTER_CONTROL;
449 
450 	if ((sc->sc_ah->opmode == NL80211_IFTYPE_STATION) &&
451 	    (sc->nvifs <= 1) &&
452 	    !(sc->rx.rxfilter & FIF_BCN_PRBRESP_PROMISC))
453 		rfilt |= ATH9K_RX_FILTER_MYBEACON;
454 	else
455 		rfilt |= ATH9K_RX_FILTER_BEACON;
456 
457 	if ((sc->sc_ah->opmode == NL80211_IFTYPE_AP) ||
458 	    (sc->rx.rxfilter & FIF_PSPOLL))
459 		rfilt |= ATH9K_RX_FILTER_PSPOLL;
460 
461 	if (conf_is_ht(&sc->hw->conf))
462 		rfilt |= ATH9K_RX_FILTER_COMP_BAR;
463 
464 	if (sc->nvifs > 1 || (sc->rx.rxfilter & FIF_OTHER_BSS)) {
465 		/* The following may also be needed for other older chips */
466 		if (sc->sc_ah->hw_version.macVersion == AR_SREV_VERSION_9160)
467 			rfilt |= ATH9K_RX_FILTER_PROM;
468 		rfilt |= ATH9K_RX_FILTER_MCAST_BCAST_ALL;
469 	}
470 
471 	return rfilt;
472 
473 #undef RX_FILTER_PRESERVE
474 }
475 
476 int ath_startrecv(struct ath_softc *sc)
477 {
478 	struct ath_hw *ah = sc->sc_ah;
479 	struct ath_buf *bf, *tbf;
480 
481 	if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
482 		ath_edma_start_recv(sc);
483 		return 0;
484 	}
485 
486 	spin_lock_bh(&sc->rx.rxbuflock);
487 	if (list_empty(&sc->rx.rxbuf))
488 		goto start_recv;
489 
490 	sc->rx.rxlink = NULL;
491 	list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list) {
492 		ath_rx_buf_link(sc, bf);
493 	}
494 
495 	/* We could have deleted elements so the list may be empty now */
496 	if (list_empty(&sc->rx.rxbuf))
497 		goto start_recv;
498 
499 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
500 	ath9k_hw_putrxbuf(ah, bf->bf_daddr);
501 	ath9k_hw_rxena(ah);
502 
503 start_recv:
504 	ath_opmode_init(sc);
505 	ath9k_hw_startpcureceive(ah, (sc->sc_flags & SC_OP_OFFCHANNEL));
506 
507 	spin_unlock_bh(&sc->rx.rxbuflock);
508 
509 	return 0;
510 }
511 
512 bool ath_stoprecv(struct ath_softc *sc)
513 {
514 	struct ath_hw *ah = sc->sc_ah;
515 	bool stopped, reset = false;
516 
517 	spin_lock_bh(&sc->rx.rxbuflock);
518 	ath9k_hw_abortpcurecv(ah);
519 	ath9k_hw_setrxfilter(ah, 0);
520 	stopped = ath9k_hw_stopdmarecv(ah, &reset);
521 
522 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
523 		ath_edma_stop_recv(sc);
524 	else
525 		sc->rx.rxlink = NULL;
526 	spin_unlock_bh(&sc->rx.rxbuflock);
527 
528 	if (!(ah->ah_flags & AH_UNPLUGGED) &&
529 	    unlikely(!stopped)) {
530 		ath_err(ath9k_hw_common(sc->sc_ah),
531 			"Could not stop RX, we could be "
532 			"confusing the DMA engine when we start RX up\n");
533 		ATH_DBG_WARN_ON_ONCE(!stopped);
534 	}
535 	return stopped && !reset;
536 }
537 
538 void ath_flushrecv(struct ath_softc *sc)
539 {
540 	sc->sc_flags |= SC_OP_RXFLUSH;
541 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
542 		ath_rx_tasklet(sc, 1, true);
543 	ath_rx_tasklet(sc, 1, false);
544 	sc->sc_flags &= ~SC_OP_RXFLUSH;
545 }
546 
547 static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
548 {
549 	/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */
550 	struct ieee80211_mgmt *mgmt;
551 	u8 *pos, *end, id, elen;
552 	struct ieee80211_tim_ie *tim;
553 
554 	mgmt = (struct ieee80211_mgmt *)skb->data;
555 	pos = mgmt->u.beacon.variable;
556 	end = skb->data + skb->len;
557 
558 	while (pos + 2 < end) {
559 		id = *pos++;
560 		elen = *pos++;
561 		if (pos + elen > end)
562 			break;
563 
564 		if (id == WLAN_EID_TIM) {
565 			if (elen < sizeof(*tim))
566 				break;
567 			tim = (struct ieee80211_tim_ie *) pos;
568 			if (tim->dtim_count != 0)
569 				break;
570 			return tim->bitmap_ctrl & 0x01;
571 		}
572 
573 		pos += elen;
574 	}
575 
576 	return false;
577 }
578 
579 static void ath_rx_ps_beacon(struct ath_softc *sc, struct sk_buff *skb)
580 {
581 	struct ieee80211_mgmt *mgmt;
582 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
583 
584 	if (skb->len < 24 + 8 + 2 + 2)
585 		return;
586 
587 	mgmt = (struct ieee80211_mgmt *)skb->data;
588 	if (memcmp(common->curbssid, mgmt->bssid, ETH_ALEN) != 0) {
589 		/* TODO:  This doesn't work well if you have stations
590 		 * associated to two different APs because curbssid
591 		 * is just the last AP that any of the stations associated
592 		 * with.
593 		 */
594 		return; /* not from our current AP */
595 	}
596 
597 	sc->ps_flags &= ~PS_WAIT_FOR_BEACON;
598 
599 	if (sc->ps_flags & PS_BEACON_SYNC) {
600 		sc->ps_flags &= ~PS_BEACON_SYNC;
601 		ath_dbg(common, ATH_DBG_PS,
602 			"Reconfigure Beacon timers based on timestamp from the AP\n");
603 		ath_set_beacon(sc);
604 		sc->ps_flags &= ~PS_TSFOOR_SYNC;
605 	}
606 
607 	if (ath_beacon_dtim_pending_cab(skb)) {
608 		/*
609 		 * Remain awake waiting for buffered broadcast/multicast
610 		 * frames. If the last broadcast/multicast frame is not
611 		 * received properly, the next beacon frame will work as
612 		 * a backup trigger for returning into NETWORK SLEEP state,
613 		 * so we are waiting for it as well.
614 		 */
615 		ath_dbg(common, ATH_DBG_PS,
616 			"Received DTIM beacon indicating buffered broadcast/multicast frame(s)\n");
617 		sc->ps_flags |= PS_WAIT_FOR_CAB | PS_WAIT_FOR_BEACON;
618 		return;
619 	}
620 
621 	if (sc->ps_flags & PS_WAIT_FOR_CAB) {
622 		/*
623 		 * This can happen if a broadcast frame is dropped or the AP
624 		 * fails to send a frame indicating that all CAB frames have
625 		 * been delivered.
626 		 */
627 		sc->ps_flags &= ~PS_WAIT_FOR_CAB;
628 		ath_dbg(common, ATH_DBG_PS,
629 			"PS wait for CAB frames timed out\n");
630 	}
631 }
632 
633 static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb)
634 {
635 	struct ieee80211_hdr *hdr;
636 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
637 
638 	hdr = (struct ieee80211_hdr *)skb->data;
639 
640 	/* Process Beacon and CAB receive in PS state */
641 	if (((sc->ps_flags & PS_WAIT_FOR_BEACON) || ath9k_check_auto_sleep(sc))
642 	    && ieee80211_is_beacon(hdr->frame_control))
643 		ath_rx_ps_beacon(sc, skb);
644 	else if ((sc->ps_flags & PS_WAIT_FOR_CAB) &&
645 		 (ieee80211_is_data(hdr->frame_control) ||
646 		  ieee80211_is_action(hdr->frame_control)) &&
647 		 is_multicast_ether_addr(hdr->addr1) &&
648 		 !ieee80211_has_moredata(hdr->frame_control)) {
649 		/*
650 		 * No more broadcast/multicast frames to be received at this
651 		 * point.
652 		 */
653 		sc->ps_flags &= ~(PS_WAIT_FOR_CAB | PS_WAIT_FOR_BEACON);
654 		ath_dbg(common, ATH_DBG_PS,
655 			"All PS CAB frames received, back to sleep\n");
656 	} else if ((sc->ps_flags & PS_WAIT_FOR_PSPOLL_DATA) &&
657 		   !is_multicast_ether_addr(hdr->addr1) &&
658 		   !ieee80211_has_morefrags(hdr->frame_control)) {
659 		sc->ps_flags &= ~PS_WAIT_FOR_PSPOLL_DATA;
660 		ath_dbg(common, ATH_DBG_PS,
661 			"Going back to sleep after having received PS-Poll data (0x%lx)\n",
662 			sc->ps_flags & (PS_WAIT_FOR_BEACON |
663 					PS_WAIT_FOR_CAB |
664 					PS_WAIT_FOR_PSPOLL_DATA |
665 					PS_WAIT_FOR_TX_ACK));
666 	}
667 }
668 
669 static bool ath_edma_get_buffers(struct ath_softc *sc,
670 				 enum ath9k_rx_qtype qtype)
671 {
672 	struct ath_rx_edma *rx_edma = &sc->rx.rx_edma[qtype];
673 	struct ath_hw *ah = sc->sc_ah;
674 	struct ath_common *common = ath9k_hw_common(ah);
675 	struct sk_buff *skb;
676 	struct ath_buf *bf;
677 	int ret;
678 
679 	skb = skb_peek(&rx_edma->rx_fifo);
680 	if (!skb)
681 		return false;
682 
683 	bf = SKB_CB_ATHBUF(skb);
684 	BUG_ON(!bf);
685 
686 	dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
687 				common->rx_bufsize, DMA_FROM_DEVICE);
688 
689 	ret = ath9k_hw_process_rxdesc_edma(ah, NULL, skb->data);
690 	if (ret == -EINPROGRESS) {
691 		/*let device gain the buffer again*/
692 		dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
693 				common->rx_bufsize, DMA_FROM_DEVICE);
694 		return false;
695 	}
696 
697 	__skb_unlink(skb, &rx_edma->rx_fifo);
698 	if (ret == -EINVAL) {
699 		/* corrupt descriptor, skip this one and the following one */
700 		list_add_tail(&bf->list, &sc->rx.rxbuf);
701 		ath_rx_edma_buf_link(sc, qtype);
702 		skb = skb_peek(&rx_edma->rx_fifo);
703 		if (!skb)
704 			return true;
705 
706 		bf = SKB_CB_ATHBUF(skb);
707 		BUG_ON(!bf);
708 
709 		__skb_unlink(skb, &rx_edma->rx_fifo);
710 		list_add_tail(&bf->list, &sc->rx.rxbuf);
711 		ath_rx_edma_buf_link(sc, qtype);
712 		return true;
713 	}
714 	skb_queue_tail(&rx_edma->rx_buffers, skb);
715 
716 	return true;
717 }
718 
719 static struct ath_buf *ath_edma_get_next_rx_buf(struct ath_softc *sc,
720 						struct ath_rx_status *rs,
721 						enum ath9k_rx_qtype qtype)
722 {
723 	struct ath_rx_edma *rx_edma = &sc->rx.rx_edma[qtype];
724 	struct sk_buff *skb;
725 	struct ath_buf *bf;
726 
727 	while (ath_edma_get_buffers(sc, qtype));
728 	skb = __skb_dequeue(&rx_edma->rx_buffers);
729 	if (!skb)
730 		return NULL;
731 
732 	bf = SKB_CB_ATHBUF(skb);
733 	ath9k_hw_process_rxdesc_edma(sc->sc_ah, rs, skb->data);
734 	return bf;
735 }
736 
737 static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc,
738 					   struct ath_rx_status *rs)
739 {
740 	struct ath_hw *ah = sc->sc_ah;
741 	struct ath_common *common = ath9k_hw_common(ah);
742 	struct ath_desc *ds;
743 	struct ath_buf *bf;
744 	int ret;
745 
746 	if (list_empty(&sc->rx.rxbuf)) {
747 		sc->rx.rxlink = NULL;
748 		return NULL;
749 	}
750 
751 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
752 	ds = bf->bf_desc;
753 
754 	/*
755 	 * Must provide the virtual address of the current
756 	 * descriptor, the physical address, and the virtual
757 	 * address of the next descriptor in the h/w chain.
758 	 * This allows the HAL to look ahead to see if the
759 	 * hardware is done with a descriptor by checking the
760 	 * done bit in the following descriptor and the address
761 	 * of the current descriptor the DMA engine is working
762 	 * on.  All this is necessary because of our use of
763 	 * a self-linked list to avoid rx overruns.
764 	 */
765 	ret = ath9k_hw_rxprocdesc(ah, ds, rs, 0);
766 	if (ret == -EINPROGRESS) {
767 		struct ath_rx_status trs;
768 		struct ath_buf *tbf;
769 		struct ath_desc *tds;
770 
771 		memset(&trs, 0, sizeof(trs));
772 		if (list_is_last(&bf->list, &sc->rx.rxbuf)) {
773 			sc->rx.rxlink = NULL;
774 			return NULL;
775 		}
776 
777 		tbf = list_entry(bf->list.next, struct ath_buf, list);
778 
779 		/*
780 		 * On some hardware the descriptor status words could
781 		 * get corrupted, including the done bit. Because of
782 		 * this, check if the next descriptor's done bit is
783 		 * set or not.
784 		 *
785 		 * If the next descriptor's done bit is set, the current
786 		 * descriptor has been corrupted. Force s/w to discard
787 		 * this descriptor and continue...
788 		 */
789 
790 		tds = tbf->bf_desc;
791 		ret = ath9k_hw_rxprocdesc(ah, tds, &trs, 0);
792 		if (ret == -EINPROGRESS)
793 			return NULL;
794 	}
795 
796 	if (!bf->bf_mpdu)
797 		return bf;
798 
799 	/*
800 	 * Synchronize the DMA transfer with CPU before
801 	 * 1. accessing the frame
802 	 * 2. requeueing the same buffer to h/w
803 	 */
804 	dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
805 			common->rx_bufsize,
806 			DMA_FROM_DEVICE);
807 
808 	return bf;
809 }
810 
811 /* Assumes you've already done the endian to CPU conversion */
812 static bool ath9k_rx_accept(struct ath_common *common,
813 			    struct ieee80211_hdr *hdr,
814 			    struct ieee80211_rx_status *rxs,
815 			    struct ath_rx_status *rx_stats,
816 			    bool *decrypt_error)
817 {
818 	bool is_mc, is_valid_tkip, strip_mic, mic_error;
819 	struct ath_hw *ah = common->ah;
820 	__le16 fc;
821 	u8 rx_status_len = ah->caps.rx_status_len;
822 
823 	fc = hdr->frame_control;
824 
825 	is_mc = !!is_multicast_ether_addr(hdr->addr1);
826 	is_valid_tkip = rx_stats->rs_keyix != ATH9K_RXKEYIX_INVALID &&
827 		test_bit(rx_stats->rs_keyix, common->tkip_keymap);
828 	strip_mic = is_valid_tkip && !(rx_stats->rs_status &
829 		(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_CRC | ATH9K_RXERR_MIC));
830 
831 	if (!rx_stats->rs_datalen)
832 		return false;
833         /*
834          * rs_status follows rs_datalen so if rs_datalen is too large
835          * we can take a hint that hardware corrupted it, so ignore
836          * those frames.
837          */
838 	if (rx_stats->rs_datalen > (common->rx_bufsize - rx_status_len))
839 		return false;
840 
841 	/* Only use error bits from the last fragment */
842 	if (rx_stats->rs_more)
843 		return true;
844 
845 	mic_error = is_valid_tkip && !ieee80211_is_ctl(fc) &&
846 		!ieee80211_has_morefrags(fc) &&
847 		!(le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG) &&
848 		(rx_stats->rs_status & ATH9K_RXERR_MIC);
849 
850 	/*
851 	 * The rx_stats->rs_status will not be set until the end of the
852 	 * chained descriptors so it can be ignored if rs_more is set. The
853 	 * rs_more will be false at the last element of the chained
854 	 * descriptors.
855 	 */
856 	if (rx_stats->rs_status != 0) {
857 		if (rx_stats->rs_status & ATH9K_RXERR_CRC) {
858 			rxs->flag |= RX_FLAG_FAILED_FCS_CRC;
859 			mic_error = false;
860 		}
861 		if (rx_stats->rs_status & ATH9K_RXERR_PHY)
862 			return false;
863 
864 		if (rx_stats->rs_status & ATH9K_RXERR_DECRYPT) {
865 			*decrypt_error = true;
866 			mic_error = false;
867 		}
868 
869 		/*
870 		 * Reject error frames with the exception of
871 		 * decryption and MIC failures. For monitor mode,
872 		 * we also ignore the CRC error.
873 		 */
874 		if (ah->is_monitoring) {
875 			if (rx_stats->rs_status &
876 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
877 			      ATH9K_RXERR_CRC))
878 				return false;
879 		} else {
880 			if (rx_stats->rs_status &
881 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC)) {
882 				return false;
883 			}
884 		}
885 	}
886 
887 	/*
888 	 * For unicast frames the MIC error bit can have false positives,
889 	 * so all MIC error reports need to be validated in software.
890 	 * False negatives are not common, so skip software verification
891 	 * if the hardware considers the MIC valid.
892 	 */
893 	if (strip_mic)
894 		rxs->flag |= RX_FLAG_MMIC_STRIPPED;
895 	else if (is_mc && mic_error)
896 		rxs->flag |= RX_FLAG_MMIC_ERROR;
897 
898 	return true;
899 }
900 
901 static int ath9k_process_rate(struct ath_common *common,
902 			      struct ieee80211_hw *hw,
903 			      struct ath_rx_status *rx_stats,
904 			      struct ieee80211_rx_status *rxs)
905 {
906 	struct ieee80211_supported_band *sband;
907 	enum ieee80211_band band;
908 	unsigned int i = 0;
909 
910 	band = hw->conf.channel->band;
911 	sband = hw->wiphy->bands[band];
912 
913 	if (rx_stats->rs_rate & 0x80) {
914 		/* HT rate */
915 		rxs->flag |= RX_FLAG_HT;
916 		if (rx_stats->rs_flags & ATH9K_RX_2040)
917 			rxs->flag |= RX_FLAG_40MHZ;
918 		if (rx_stats->rs_flags & ATH9K_RX_GI)
919 			rxs->flag |= RX_FLAG_SHORT_GI;
920 		rxs->rate_idx = rx_stats->rs_rate & 0x7f;
921 		return 0;
922 	}
923 
924 	for (i = 0; i < sband->n_bitrates; i++) {
925 		if (sband->bitrates[i].hw_value == rx_stats->rs_rate) {
926 			rxs->rate_idx = i;
927 			return 0;
928 		}
929 		if (sband->bitrates[i].hw_value_short == rx_stats->rs_rate) {
930 			rxs->flag |= RX_FLAG_SHORTPRE;
931 			rxs->rate_idx = i;
932 			return 0;
933 		}
934 	}
935 
936 	/*
937 	 * No valid hardware bitrate found -- we should not get here
938 	 * because hardware has already validated this frame as OK.
939 	 */
940 	ath_dbg(common, ATH_DBG_XMIT,
941 		"unsupported hw bitrate detected 0x%02x using 1 Mbit\n",
942 		rx_stats->rs_rate);
943 
944 	return -EINVAL;
945 }
946 
947 static void ath9k_process_rssi(struct ath_common *common,
948 			       struct ieee80211_hw *hw,
949 			       struct ieee80211_hdr *hdr,
950 			       struct ath_rx_status *rx_stats)
951 {
952 	struct ath_softc *sc = hw->priv;
953 	struct ath_hw *ah = common->ah;
954 	int last_rssi;
955 	__le16 fc;
956 
957 	if ((ah->opmode != NL80211_IFTYPE_STATION) &&
958 	    (ah->opmode != NL80211_IFTYPE_ADHOC))
959 		return;
960 
961 	fc = hdr->frame_control;
962 	if (!ieee80211_is_beacon(fc) ||
963 	    compare_ether_addr(hdr->addr3, common->curbssid)) {
964 		/* TODO:  This doesn't work well if you have stations
965 		 * associated to two different APs because curbssid
966 		 * is just the last AP that any of the stations associated
967 		 * with.
968 		 */
969 		return;
970 	}
971 
972 	if (rx_stats->rs_rssi != ATH9K_RSSI_BAD && !rx_stats->rs_moreaggr)
973 		ATH_RSSI_LPF(sc->last_rssi, rx_stats->rs_rssi);
974 
975 	last_rssi = sc->last_rssi;
976 	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
977 		rx_stats->rs_rssi = ATH_EP_RND(last_rssi,
978 					      ATH_RSSI_EP_MULTIPLIER);
979 	if (rx_stats->rs_rssi < 0)
980 		rx_stats->rs_rssi = 0;
981 
982 	/* Update Beacon RSSI, this is used by ANI. */
983 	ah->stats.avgbrssi = rx_stats->rs_rssi;
984 }
985 
986 /*
987  * For Decrypt or Demic errors, we only mark packet status here and always push
988  * up the frame up to let mac80211 handle the actual error case, be it no
989  * decryption key or real decryption error. This let us keep statistics there.
990  */
991 static int ath9k_rx_skb_preprocess(struct ath_common *common,
992 				   struct ieee80211_hw *hw,
993 				   struct ieee80211_hdr *hdr,
994 				   struct ath_rx_status *rx_stats,
995 				   struct ieee80211_rx_status *rx_status,
996 				   bool *decrypt_error)
997 {
998 	memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
999 
1000 	/*
1001 	 * everything but the rate is checked here, the rate check is done
1002 	 * separately to avoid doing two lookups for a rate for each frame.
1003 	 */
1004 	if (!ath9k_rx_accept(common, hdr, rx_status, rx_stats, decrypt_error))
1005 		return -EINVAL;
1006 
1007 	/* Only use status info from the last fragment */
1008 	if (rx_stats->rs_more)
1009 		return 0;
1010 
1011 	ath9k_process_rssi(common, hw, hdr, rx_stats);
1012 
1013 	if (ath9k_process_rate(common, hw, rx_stats, rx_status))
1014 		return -EINVAL;
1015 
1016 	rx_status->band = hw->conf.channel->band;
1017 	rx_status->freq = hw->conf.channel->center_freq;
1018 	rx_status->signal = ATH_DEFAULT_NOISE_FLOOR + rx_stats->rs_rssi;
1019 	rx_status->antenna = rx_stats->rs_antenna;
1020 	rx_status->flag |= RX_FLAG_MACTIME_MPDU;
1021 
1022 	return 0;
1023 }
1024 
1025 static void ath9k_rx_skb_postprocess(struct ath_common *common,
1026 				     struct sk_buff *skb,
1027 				     struct ath_rx_status *rx_stats,
1028 				     struct ieee80211_rx_status *rxs,
1029 				     bool decrypt_error)
1030 {
1031 	struct ath_hw *ah = common->ah;
1032 	struct ieee80211_hdr *hdr;
1033 	int hdrlen, padpos, padsize;
1034 	u8 keyix;
1035 	__le16 fc;
1036 
1037 	/* see if any padding is done by the hw and remove it */
1038 	hdr = (struct ieee80211_hdr *) skb->data;
1039 	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
1040 	fc = hdr->frame_control;
1041 	padpos = ath9k_cmn_padpos(hdr->frame_control);
1042 
1043 	/* The MAC header is padded to have 32-bit boundary if the
1044 	 * packet payload is non-zero. The general calculation for
1045 	 * padsize would take into account odd header lengths:
1046 	 * padsize = (4 - padpos % 4) % 4; However, since only
1047 	 * even-length headers are used, padding can only be 0 or 2
1048 	 * bytes and we can optimize this a bit. In addition, we must
1049 	 * not try to remove padding from short control frames that do
1050 	 * not have payload. */
1051 	padsize = padpos & 3;
1052 	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
1053 		memmove(skb->data + padsize, skb->data, padpos);
1054 		skb_pull(skb, padsize);
1055 	}
1056 
1057 	keyix = rx_stats->rs_keyix;
1058 
1059 	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error &&
1060 	    ieee80211_has_protected(fc)) {
1061 		rxs->flag |= RX_FLAG_DECRYPTED;
1062 	} else if (ieee80211_has_protected(fc)
1063 		   && !decrypt_error && skb->len >= hdrlen + 4) {
1064 		keyix = skb->data[hdrlen + 3] >> 6;
1065 
1066 		if (test_bit(keyix, common->keymap))
1067 			rxs->flag |= RX_FLAG_DECRYPTED;
1068 	}
1069 	if (ah->sw_mgmt_crypto &&
1070 	    (rxs->flag & RX_FLAG_DECRYPTED) &&
1071 	    ieee80211_is_mgmt(fc))
1072 		/* Use software decrypt for management frames. */
1073 		rxs->flag &= ~RX_FLAG_DECRYPTED;
1074 }
1075 
1076 static void ath_lnaconf_alt_good_scan(struct ath_ant_comb *antcomb,
1077 				      struct ath_hw_antcomb_conf ant_conf,
1078 				      int main_rssi_avg)
1079 {
1080 	antcomb->quick_scan_cnt = 0;
1081 
1082 	if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
1083 		antcomb->rssi_lna2 = main_rssi_avg;
1084 	else if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA1)
1085 		antcomb->rssi_lna1 = main_rssi_avg;
1086 
1087 	switch ((ant_conf.main_lna_conf << 4) | ant_conf.alt_lna_conf) {
1088 	case 0x10: /* LNA2 A-B */
1089 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1090 		antcomb->first_quick_scan_conf =
1091 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1092 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
1093 		break;
1094 	case 0x20: /* LNA1 A-B */
1095 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1096 		antcomb->first_quick_scan_conf =
1097 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1098 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
1099 		break;
1100 	case 0x21: /* LNA1 LNA2 */
1101 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA2;
1102 		antcomb->first_quick_scan_conf =
1103 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1104 		antcomb->second_quick_scan_conf =
1105 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1106 		break;
1107 	case 0x12: /* LNA2 LNA1 */
1108 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1;
1109 		antcomb->first_quick_scan_conf =
1110 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1111 		antcomb->second_quick_scan_conf =
1112 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1113 		break;
1114 	case 0x13: /* LNA2 A+B */
1115 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1116 		antcomb->first_quick_scan_conf =
1117 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1118 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
1119 		break;
1120 	case 0x23: /* LNA1 A+B */
1121 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1122 		antcomb->first_quick_scan_conf =
1123 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1124 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
1125 		break;
1126 	default:
1127 		break;
1128 	}
1129 }
1130 
1131 static void ath_select_ant_div_from_quick_scan(struct ath_ant_comb *antcomb,
1132 				struct ath_hw_antcomb_conf *div_ant_conf,
1133 				int main_rssi_avg, int alt_rssi_avg,
1134 				int alt_ratio)
1135 {
1136 	/* alt_good */
1137 	switch (antcomb->quick_scan_cnt) {
1138 	case 0:
1139 		/* set alt to main, and alt to first conf */
1140 		div_ant_conf->main_lna_conf = antcomb->main_conf;
1141 		div_ant_conf->alt_lna_conf = antcomb->first_quick_scan_conf;
1142 		break;
1143 	case 1:
1144 		/* set alt to main, and alt to first conf */
1145 		div_ant_conf->main_lna_conf = antcomb->main_conf;
1146 		div_ant_conf->alt_lna_conf = antcomb->second_quick_scan_conf;
1147 		antcomb->rssi_first = main_rssi_avg;
1148 		antcomb->rssi_second = alt_rssi_avg;
1149 
1150 		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
1151 			/* main is LNA1 */
1152 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1153 						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
1154 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1155 						main_rssi_avg, alt_rssi_avg,
1156 						antcomb->total_pkt_count))
1157 				antcomb->first_ratio = true;
1158 			else
1159 				antcomb->first_ratio = false;
1160 		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
1161 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1162 						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
1163 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1164 						main_rssi_avg, alt_rssi_avg,
1165 						antcomb->total_pkt_count))
1166 				antcomb->first_ratio = true;
1167 			else
1168 				antcomb->first_ratio = false;
1169 		} else {
1170 			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
1171 			    (alt_rssi_avg > main_rssi_avg +
1172 			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
1173 			    (alt_rssi_avg > main_rssi_avg)) &&
1174 			    (antcomb->total_pkt_count > 50))
1175 				antcomb->first_ratio = true;
1176 			else
1177 				antcomb->first_ratio = false;
1178 		}
1179 		break;
1180 	case 2:
1181 		antcomb->alt_good = false;
1182 		antcomb->scan_not_start = false;
1183 		antcomb->scan = false;
1184 		antcomb->rssi_first = main_rssi_avg;
1185 		antcomb->rssi_third = alt_rssi_avg;
1186 
1187 		if (antcomb->second_quick_scan_conf == ATH_ANT_DIV_COMB_LNA1)
1188 			antcomb->rssi_lna1 = alt_rssi_avg;
1189 		else if (antcomb->second_quick_scan_conf ==
1190 			 ATH_ANT_DIV_COMB_LNA2)
1191 			antcomb->rssi_lna2 = alt_rssi_avg;
1192 		else if (antcomb->second_quick_scan_conf ==
1193 			 ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2) {
1194 			if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2)
1195 				antcomb->rssi_lna2 = main_rssi_avg;
1196 			else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1)
1197 				antcomb->rssi_lna1 = main_rssi_avg;
1198 		}
1199 
1200 		if (antcomb->rssi_lna2 > antcomb->rssi_lna1 +
1201 		    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)
1202 			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
1203 		else
1204 			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
1205 
1206 		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
1207 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1208 						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
1209 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1210 						main_rssi_avg, alt_rssi_avg,
1211 						antcomb->total_pkt_count))
1212 				antcomb->second_ratio = true;
1213 			else
1214 				antcomb->second_ratio = false;
1215 		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
1216 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1217 						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
1218 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1219 						main_rssi_avg, alt_rssi_avg,
1220 						antcomb->total_pkt_count))
1221 				antcomb->second_ratio = true;
1222 			else
1223 				antcomb->second_ratio = false;
1224 		} else {
1225 			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
1226 			    (alt_rssi_avg > main_rssi_avg +
1227 			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
1228 			    (alt_rssi_avg > main_rssi_avg)) &&
1229 			    (antcomb->total_pkt_count > 50))
1230 				antcomb->second_ratio = true;
1231 			else
1232 				antcomb->second_ratio = false;
1233 		}
1234 
1235 		/* set alt to the conf with maximun ratio */
1236 		if (antcomb->first_ratio && antcomb->second_ratio) {
1237 			if (antcomb->rssi_second > antcomb->rssi_third) {
1238 				/* first alt*/
1239 				if ((antcomb->first_quick_scan_conf ==
1240 				    ATH_ANT_DIV_COMB_LNA1) ||
1241 				    (antcomb->first_quick_scan_conf ==
1242 				    ATH_ANT_DIV_COMB_LNA2))
1243 					/* Set alt LNA1 or LNA2*/
1244 					if (div_ant_conf->main_lna_conf ==
1245 					    ATH_ANT_DIV_COMB_LNA2)
1246 						div_ant_conf->alt_lna_conf =
1247 							ATH_ANT_DIV_COMB_LNA1;
1248 					else
1249 						div_ant_conf->alt_lna_conf =
1250 							ATH_ANT_DIV_COMB_LNA2;
1251 				else
1252 					/* Set alt to A+B or A-B */
1253 					div_ant_conf->alt_lna_conf =
1254 						antcomb->first_quick_scan_conf;
1255 			} else if ((antcomb->second_quick_scan_conf ==
1256 				   ATH_ANT_DIV_COMB_LNA1) ||
1257 				   (antcomb->second_quick_scan_conf ==
1258 				   ATH_ANT_DIV_COMB_LNA2)) {
1259 				/* Set alt LNA1 or LNA2 */
1260 				if (div_ant_conf->main_lna_conf ==
1261 				    ATH_ANT_DIV_COMB_LNA2)
1262 					div_ant_conf->alt_lna_conf =
1263 						ATH_ANT_DIV_COMB_LNA1;
1264 				else
1265 					div_ant_conf->alt_lna_conf =
1266 						ATH_ANT_DIV_COMB_LNA2;
1267 			} else {
1268 				/* Set alt to A+B or A-B */
1269 				div_ant_conf->alt_lna_conf =
1270 					antcomb->second_quick_scan_conf;
1271 			}
1272 		} else if (antcomb->first_ratio) {
1273 			/* first alt */
1274 			if ((antcomb->first_quick_scan_conf ==
1275 			    ATH_ANT_DIV_COMB_LNA1) ||
1276 			    (antcomb->first_quick_scan_conf ==
1277 			    ATH_ANT_DIV_COMB_LNA2))
1278 					/* Set alt LNA1 or LNA2 */
1279 				if (div_ant_conf->main_lna_conf ==
1280 				    ATH_ANT_DIV_COMB_LNA2)
1281 					div_ant_conf->alt_lna_conf =
1282 							ATH_ANT_DIV_COMB_LNA1;
1283 				else
1284 					div_ant_conf->alt_lna_conf =
1285 							ATH_ANT_DIV_COMB_LNA2;
1286 			else
1287 				/* Set alt to A+B or A-B */
1288 				div_ant_conf->alt_lna_conf =
1289 						antcomb->first_quick_scan_conf;
1290 		} else if (antcomb->second_ratio) {
1291 				/* second alt */
1292 			if ((antcomb->second_quick_scan_conf ==
1293 			    ATH_ANT_DIV_COMB_LNA1) ||
1294 			    (antcomb->second_quick_scan_conf ==
1295 			    ATH_ANT_DIV_COMB_LNA2))
1296 				/* Set alt LNA1 or LNA2 */
1297 				if (div_ant_conf->main_lna_conf ==
1298 				    ATH_ANT_DIV_COMB_LNA2)
1299 					div_ant_conf->alt_lna_conf =
1300 						ATH_ANT_DIV_COMB_LNA1;
1301 				else
1302 					div_ant_conf->alt_lna_conf =
1303 						ATH_ANT_DIV_COMB_LNA2;
1304 			else
1305 				/* Set alt to A+B or A-B */
1306 				div_ant_conf->alt_lna_conf =
1307 						antcomb->second_quick_scan_conf;
1308 		} else {
1309 			/* main is largest */
1310 			if ((antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) ||
1311 			    (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2))
1312 				/* Set alt LNA1 or LNA2 */
1313 				if (div_ant_conf->main_lna_conf ==
1314 				    ATH_ANT_DIV_COMB_LNA2)
1315 					div_ant_conf->alt_lna_conf =
1316 							ATH_ANT_DIV_COMB_LNA1;
1317 				else
1318 					div_ant_conf->alt_lna_conf =
1319 							ATH_ANT_DIV_COMB_LNA2;
1320 			else
1321 				/* Set alt to A+B or A-B */
1322 				div_ant_conf->alt_lna_conf = antcomb->main_conf;
1323 		}
1324 		break;
1325 	default:
1326 		break;
1327 	}
1328 }
1329 
1330 static void ath_ant_div_conf_fast_divbias(struct ath_hw_antcomb_conf *ant_conf,
1331 		struct ath_ant_comb *antcomb, int alt_ratio)
1332 {
1333 	if (ant_conf->div_group == 0) {
1334 		/* Adjust the fast_div_bias based on main and alt lna conf */
1335 		switch ((ant_conf->main_lna_conf << 4) |
1336 				ant_conf->alt_lna_conf) {
1337 		case 0x01: /* A-B LNA2 */
1338 			ant_conf->fast_div_bias = 0x3b;
1339 			break;
1340 		case 0x02: /* A-B LNA1 */
1341 			ant_conf->fast_div_bias = 0x3d;
1342 			break;
1343 		case 0x03: /* A-B A+B */
1344 			ant_conf->fast_div_bias = 0x1;
1345 			break;
1346 		case 0x10: /* LNA2 A-B */
1347 			ant_conf->fast_div_bias = 0x7;
1348 			break;
1349 		case 0x12: /* LNA2 LNA1 */
1350 			ant_conf->fast_div_bias = 0x2;
1351 			break;
1352 		case 0x13: /* LNA2 A+B */
1353 			ant_conf->fast_div_bias = 0x7;
1354 			break;
1355 		case 0x20: /* LNA1 A-B */
1356 			ant_conf->fast_div_bias = 0x6;
1357 			break;
1358 		case 0x21: /* LNA1 LNA2 */
1359 			ant_conf->fast_div_bias = 0x0;
1360 			break;
1361 		case 0x23: /* LNA1 A+B */
1362 			ant_conf->fast_div_bias = 0x6;
1363 			break;
1364 		case 0x30: /* A+B A-B */
1365 			ant_conf->fast_div_bias = 0x1;
1366 			break;
1367 		case 0x31: /* A+B LNA2 */
1368 			ant_conf->fast_div_bias = 0x3b;
1369 			break;
1370 		case 0x32: /* A+B LNA1 */
1371 			ant_conf->fast_div_bias = 0x3d;
1372 			break;
1373 		default:
1374 			break;
1375 		}
1376 	} else if (ant_conf->div_group == 1) {
1377 		/* Adjust the fast_div_bias based on main and alt_lna_conf */
1378 		switch ((ant_conf->main_lna_conf << 4) |
1379 			ant_conf->alt_lna_conf) {
1380 		case 0x01: /* A-B LNA2 */
1381 			ant_conf->fast_div_bias = 0x1;
1382 			ant_conf->main_gaintb = 0;
1383 			ant_conf->alt_gaintb = 0;
1384 			break;
1385 		case 0x02: /* A-B LNA1 */
1386 			ant_conf->fast_div_bias = 0x1;
1387 			ant_conf->main_gaintb = 0;
1388 			ant_conf->alt_gaintb = 0;
1389 			break;
1390 		case 0x03: /* A-B A+B */
1391 			ant_conf->fast_div_bias = 0x1;
1392 			ant_conf->main_gaintb = 0;
1393 			ant_conf->alt_gaintb = 0;
1394 			break;
1395 		case 0x10: /* LNA2 A-B */
1396 			if (!(antcomb->scan) &&
1397 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1398 				ant_conf->fast_div_bias = 0x3f;
1399 			else
1400 				ant_conf->fast_div_bias = 0x1;
1401 			ant_conf->main_gaintb = 0;
1402 			ant_conf->alt_gaintb = 0;
1403 			break;
1404 		case 0x12: /* LNA2 LNA1 */
1405 			ant_conf->fast_div_bias = 0x1;
1406 			ant_conf->main_gaintb = 0;
1407 			ant_conf->alt_gaintb = 0;
1408 			break;
1409 		case 0x13: /* LNA2 A+B */
1410 			if (!(antcomb->scan) &&
1411 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1412 				ant_conf->fast_div_bias = 0x3f;
1413 			else
1414 				ant_conf->fast_div_bias = 0x1;
1415 			ant_conf->main_gaintb = 0;
1416 			ant_conf->alt_gaintb = 0;
1417 			break;
1418 		case 0x20: /* LNA1 A-B */
1419 			if (!(antcomb->scan) &&
1420 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1421 				ant_conf->fast_div_bias = 0x3f;
1422 			else
1423 				ant_conf->fast_div_bias = 0x1;
1424 			ant_conf->main_gaintb = 0;
1425 			ant_conf->alt_gaintb = 0;
1426 			break;
1427 		case 0x21: /* LNA1 LNA2 */
1428 			ant_conf->fast_div_bias = 0x1;
1429 			ant_conf->main_gaintb = 0;
1430 			ant_conf->alt_gaintb = 0;
1431 			break;
1432 		case 0x23: /* LNA1 A+B */
1433 			if (!(antcomb->scan) &&
1434 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1435 				ant_conf->fast_div_bias = 0x3f;
1436 			else
1437 				ant_conf->fast_div_bias = 0x1;
1438 			ant_conf->main_gaintb = 0;
1439 			ant_conf->alt_gaintb = 0;
1440 			break;
1441 		case 0x30: /* A+B A-B */
1442 			ant_conf->fast_div_bias = 0x1;
1443 			ant_conf->main_gaintb = 0;
1444 			ant_conf->alt_gaintb = 0;
1445 			break;
1446 		case 0x31: /* A+B LNA2 */
1447 			ant_conf->fast_div_bias = 0x1;
1448 			ant_conf->main_gaintb = 0;
1449 			ant_conf->alt_gaintb = 0;
1450 			break;
1451 		case 0x32: /* A+B LNA1 */
1452 			ant_conf->fast_div_bias = 0x1;
1453 			ant_conf->main_gaintb = 0;
1454 			ant_conf->alt_gaintb = 0;
1455 			break;
1456 		default:
1457 			break;
1458 		}
1459 	} else if (ant_conf->div_group == 2) {
1460 		/* Adjust the fast_div_bias based on main and alt_lna_conf */
1461 		switch ((ant_conf->main_lna_conf << 4) |
1462 				ant_conf->alt_lna_conf) {
1463 		case 0x01: /* A-B LNA2 */
1464 			ant_conf->fast_div_bias = 0x1;
1465 			ant_conf->main_gaintb = 0;
1466 			ant_conf->alt_gaintb = 0;
1467 			break;
1468 		case 0x02: /* A-B LNA1 */
1469 			ant_conf->fast_div_bias = 0x1;
1470 			ant_conf->main_gaintb = 0;
1471 			ant_conf->alt_gaintb = 0;
1472 			break;
1473 		case 0x03: /* A-B A+B */
1474 			ant_conf->fast_div_bias = 0x1;
1475 			ant_conf->main_gaintb = 0;
1476 			ant_conf->alt_gaintb = 0;
1477 			break;
1478 		case 0x10: /* LNA2 A-B */
1479 			if (!(antcomb->scan) &&
1480 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1481 				ant_conf->fast_div_bias = 0x1;
1482 			else
1483 				ant_conf->fast_div_bias = 0x2;
1484 			ant_conf->main_gaintb = 0;
1485 			ant_conf->alt_gaintb = 0;
1486 			break;
1487 		case 0x12: /* LNA2 LNA1 */
1488 			ant_conf->fast_div_bias = 0x1;
1489 			ant_conf->main_gaintb = 0;
1490 			ant_conf->alt_gaintb = 0;
1491 			break;
1492 		case 0x13: /* LNA2 A+B */
1493 			if (!(antcomb->scan) &&
1494 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1495 				ant_conf->fast_div_bias = 0x1;
1496 			else
1497 				ant_conf->fast_div_bias = 0x2;
1498 			ant_conf->main_gaintb = 0;
1499 			ant_conf->alt_gaintb = 0;
1500 			break;
1501 		case 0x20: /* LNA1 A-B */
1502 			if (!(antcomb->scan) &&
1503 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1504 				ant_conf->fast_div_bias = 0x1;
1505 			else
1506 				ant_conf->fast_div_bias = 0x2;
1507 			ant_conf->main_gaintb = 0;
1508 			ant_conf->alt_gaintb = 0;
1509 			break;
1510 		case 0x21: /* LNA1 LNA2 */
1511 			ant_conf->fast_div_bias = 0x1;
1512 			ant_conf->main_gaintb = 0;
1513 			ant_conf->alt_gaintb = 0;
1514 			break;
1515 		case 0x23: /* LNA1 A+B */
1516 			if (!(antcomb->scan) &&
1517 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1518 				ant_conf->fast_div_bias = 0x1;
1519 			else
1520 				ant_conf->fast_div_bias = 0x2;
1521 			ant_conf->main_gaintb = 0;
1522 			ant_conf->alt_gaintb = 0;
1523 			break;
1524 		case 0x30: /* A+B A-B */
1525 			ant_conf->fast_div_bias = 0x1;
1526 			ant_conf->main_gaintb = 0;
1527 			ant_conf->alt_gaintb = 0;
1528 			break;
1529 		case 0x31: /* A+B LNA2 */
1530 			ant_conf->fast_div_bias = 0x1;
1531 			ant_conf->main_gaintb = 0;
1532 			ant_conf->alt_gaintb = 0;
1533 			break;
1534 		case 0x32: /* A+B LNA1 */
1535 			ant_conf->fast_div_bias = 0x1;
1536 			ant_conf->main_gaintb = 0;
1537 			ant_conf->alt_gaintb = 0;
1538 			break;
1539 		default:
1540 			break;
1541 		}
1542 	}
1543 }
1544 
1545 /* Antenna diversity and combining */
1546 static void ath_ant_comb_scan(struct ath_softc *sc, struct ath_rx_status *rs)
1547 {
1548 	struct ath_hw_antcomb_conf div_ant_conf;
1549 	struct ath_ant_comb *antcomb = &sc->ant_comb;
1550 	int alt_ratio = 0, alt_rssi_avg = 0, main_rssi_avg = 0, curr_alt_set;
1551 	int curr_main_set;
1552 	int main_rssi = rs->rs_rssi_ctl0;
1553 	int alt_rssi = rs->rs_rssi_ctl1;
1554 	int rx_ant_conf,  main_ant_conf;
1555 	bool short_scan = false;
1556 
1557 	rx_ant_conf = (rs->rs_rssi_ctl2 >> ATH_ANT_RX_CURRENT_SHIFT) &
1558 		       ATH_ANT_RX_MASK;
1559 	main_ant_conf = (rs->rs_rssi_ctl2 >> ATH_ANT_RX_MAIN_SHIFT) &
1560 			 ATH_ANT_RX_MASK;
1561 
1562 	/* Record packet only when both main_rssi and  alt_rssi is positive */
1563 	if (main_rssi > 0 && alt_rssi > 0) {
1564 		antcomb->total_pkt_count++;
1565 		antcomb->main_total_rssi += main_rssi;
1566 		antcomb->alt_total_rssi  += alt_rssi;
1567 		if (main_ant_conf == rx_ant_conf)
1568 			antcomb->main_recv_cnt++;
1569 		else
1570 			antcomb->alt_recv_cnt++;
1571 	}
1572 
1573 	/* Short scan check */
1574 	if (antcomb->scan && antcomb->alt_good) {
1575 		if (time_after(jiffies, antcomb->scan_start_time +
1576 		    msecs_to_jiffies(ATH_ANT_DIV_COMB_SHORT_SCAN_INTR)))
1577 			short_scan = true;
1578 		else
1579 			if (antcomb->total_pkt_count ==
1580 			    ATH_ANT_DIV_COMB_SHORT_SCAN_PKTCOUNT) {
1581 				alt_ratio = ((antcomb->alt_recv_cnt * 100) /
1582 					    antcomb->total_pkt_count);
1583 				if (alt_ratio < ATH_ANT_DIV_COMB_ALT_ANT_RATIO)
1584 					short_scan = true;
1585 			}
1586 	}
1587 
1588 	if (((antcomb->total_pkt_count < ATH_ANT_DIV_COMB_MAX_PKTCOUNT) ||
1589 	    rs->rs_moreaggr) && !short_scan)
1590 		return;
1591 
1592 	if (antcomb->total_pkt_count) {
1593 		alt_ratio = ((antcomb->alt_recv_cnt * 100) /
1594 			     antcomb->total_pkt_count);
1595 		main_rssi_avg = (antcomb->main_total_rssi /
1596 				 antcomb->total_pkt_count);
1597 		alt_rssi_avg = (antcomb->alt_total_rssi /
1598 				 antcomb->total_pkt_count);
1599 	}
1600 
1601 
1602 	ath9k_hw_antdiv_comb_conf_get(sc->sc_ah, &div_ant_conf);
1603 	curr_alt_set = div_ant_conf.alt_lna_conf;
1604 	curr_main_set = div_ant_conf.main_lna_conf;
1605 
1606 	antcomb->count++;
1607 
1608 	if (antcomb->count == ATH_ANT_DIV_COMB_MAX_COUNT) {
1609 		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO) {
1610 			ath_lnaconf_alt_good_scan(antcomb, div_ant_conf,
1611 						  main_rssi_avg);
1612 			antcomb->alt_good = true;
1613 		} else {
1614 			antcomb->alt_good = false;
1615 		}
1616 
1617 		antcomb->count = 0;
1618 		antcomb->scan = true;
1619 		antcomb->scan_not_start = true;
1620 	}
1621 
1622 	if (!antcomb->scan) {
1623 		if (ath_ant_div_comb_alt_check(div_ant_conf.div_group,
1624 					alt_ratio, curr_main_set, curr_alt_set,
1625 					alt_rssi_avg, main_rssi_avg)) {
1626 			if (curr_alt_set == ATH_ANT_DIV_COMB_LNA2) {
1627 				/* Switch main and alt LNA */
1628 				div_ant_conf.main_lna_conf =
1629 						ATH_ANT_DIV_COMB_LNA2;
1630 				div_ant_conf.alt_lna_conf  =
1631 						ATH_ANT_DIV_COMB_LNA1;
1632 			} else if (curr_alt_set == ATH_ANT_DIV_COMB_LNA1) {
1633 				div_ant_conf.main_lna_conf =
1634 						ATH_ANT_DIV_COMB_LNA1;
1635 				div_ant_conf.alt_lna_conf  =
1636 						ATH_ANT_DIV_COMB_LNA2;
1637 			}
1638 
1639 			goto div_comb_done;
1640 		} else if ((curr_alt_set != ATH_ANT_DIV_COMB_LNA1) &&
1641 			   (curr_alt_set != ATH_ANT_DIV_COMB_LNA2)) {
1642 			/* Set alt to another LNA */
1643 			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2)
1644 				div_ant_conf.alt_lna_conf =
1645 						ATH_ANT_DIV_COMB_LNA1;
1646 			else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1)
1647 				div_ant_conf.alt_lna_conf =
1648 						ATH_ANT_DIV_COMB_LNA2;
1649 
1650 			goto div_comb_done;
1651 		}
1652 
1653 		if ((alt_rssi_avg < (main_rssi_avg +
1654 						div_ant_conf.lna1_lna2_delta)))
1655 			goto div_comb_done;
1656 	}
1657 
1658 	if (!antcomb->scan_not_start) {
1659 		switch (curr_alt_set) {
1660 		case ATH_ANT_DIV_COMB_LNA2:
1661 			antcomb->rssi_lna2 = alt_rssi_avg;
1662 			antcomb->rssi_lna1 = main_rssi_avg;
1663 			antcomb->scan = true;
1664 			/* set to A+B */
1665 			div_ant_conf.main_lna_conf =
1666 				ATH_ANT_DIV_COMB_LNA1;
1667 			div_ant_conf.alt_lna_conf  =
1668 				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1669 			break;
1670 		case ATH_ANT_DIV_COMB_LNA1:
1671 			antcomb->rssi_lna1 = alt_rssi_avg;
1672 			antcomb->rssi_lna2 = main_rssi_avg;
1673 			antcomb->scan = true;
1674 			/* set to A+B */
1675 			div_ant_conf.main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
1676 			div_ant_conf.alt_lna_conf  =
1677 				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1678 			break;
1679 		case ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2:
1680 			antcomb->rssi_add = alt_rssi_avg;
1681 			antcomb->scan = true;
1682 			/* set to A-B */
1683 			div_ant_conf.alt_lna_conf =
1684 				ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1685 			break;
1686 		case ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2:
1687 			antcomb->rssi_sub = alt_rssi_avg;
1688 			antcomb->scan = false;
1689 			if (antcomb->rssi_lna2 >
1690 			    (antcomb->rssi_lna1 +
1691 			    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)) {
1692 				/* use LNA2 as main LNA */
1693 				if ((antcomb->rssi_add > antcomb->rssi_lna1) &&
1694 				    (antcomb->rssi_add > antcomb->rssi_sub)) {
1695 					/* set to A+B */
1696 					div_ant_conf.main_lna_conf =
1697 						ATH_ANT_DIV_COMB_LNA2;
1698 					div_ant_conf.alt_lna_conf  =
1699 						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1700 				} else if (antcomb->rssi_sub >
1701 					   antcomb->rssi_lna1) {
1702 					/* set to A-B */
1703 					div_ant_conf.main_lna_conf =
1704 						ATH_ANT_DIV_COMB_LNA2;
1705 					div_ant_conf.alt_lna_conf =
1706 						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1707 				} else {
1708 					/* set to LNA1 */
1709 					div_ant_conf.main_lna_conf =
1710 						ATH_ANT_DIV_COMB_LNA2;
1711 					div_ant_conf.alt_lna_conf =
1712 						ATH_ANT_DIV_COMB_LNA1;
1713 				}
1714 			} else {
1715 				/* use LNA1 as main LNA */
1716 				if ((antcomb->rssi_add > antcomb->rssi_lna2) &&
1717 				    (antcomb->rssi_add > antcomb->rssi_sub)) {
1718 					/* set to A+B */
1719 					div_ant_conf.main_lna_conf =
1720 						ATH_ANT_DIV_COMB_LNA1;
1721 					div_ant_conf.alt_lna_conf  =
1722 						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1723 				} else if (antcomb->rssi_sub >
1724 					   antcomb->rssi_lna1) {
1725 					/* set to A-B */
1726 					div_ant_conf.main_lna_conf =
1727 						ATH_ANT_DIV_COMB_LNA1;
1728 					div_ant_conf.alt_lna_conf =
1729 						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1730 				} else {
1731 					/* set to LNA2 */
1732 					div_ant_conf.main_lna_conf =
1733 						ATH_ANT_DIV_COMB_LNA1;
1734 					div_ant_conf.alt_lna_conf =
1735 						ATH_ANT_DIV_COMB_LNA2;
1736 				}
1737 			}
1738 			break;
1739 		default:
1740 			break;
1741 		}
1742 	} else {
1743 		if (!antcomb->alt_good) {
1744 			antcomb->scan_not_start = false;
1745 			/* Set alt to another LNA */
1746 			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2) {
1747 				div_ant_conf.main_lna_conf =
1748 						ATH_ANT_DIV_COMB_LNA2;
1749 				div_ant_conf.alt_lna_conf =
1750 						ATH_ANT_DIV_COMB_LNA1;
1751 			} else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1) {
1752 				div_ant_conf.main_lna_conf =
1753 						ATH_ANT_DIV_COMB_LNA1;
1754 				div_ant_conf.alt_lna_conf =
1755 						ATH_ANT_DIV_COMB_LNA2;
1756 			}
1757 			goto div_comb_done;
1758 		}
1759 	}
1760 
1761 	ath_select_ant_div_from_quick_scan(antcomb, &div_ant_conf,
1762 					   main_rssi_avg, alt_rssi_avg,
1763 					   alt_ratio);
1764 
1765 	antcomb->quick_scan_cnt++;
1766 
1767 div_comb_done:
1768 	ath_ant_div_conf_fast_divbias(&div_ant_conf, antcomb, alt_ratio);
1769 	ath9k_hw_antdiv_comb_conf_set(sc->sc_ah, &div_ant_conf);
1770 
1771 	antcomb->scan_start_time = jiffies;
1772 	antcomb->total_pkt_count = 0;
1773 	antcomb->main_total_rssi = 0;
1774 	antcomb->alt_total_rssi = 0;
1775 	antcomb->main_recv_cnt = 0;
1776 	antcomb->alt_recv_cnt = 0;
1777 }
1778 
1779 int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
1780 {
1781 	struct ath_buf *bf;
1782 	struct sk_buff *skb = NULL, *requeue_skb, *hdr_skb;
1783 	struct ieee80211_rx_status *rxs;
1784 	struct ath_hw *ah = sc->sc_ah;
1785 	struct ath_common *common = ath9k_hw_common(ah);
1786 	/*
1787 	 * The hw can technically differ from common->hw when using ath9k
1788 	 * virtual wiphy so to account for that we iterate over the active
1789 	 * wiphys and find the appropriate wiphy and therefore hw.
1790 	 */
1791 	struct ieee80211_hw *hw = sc->hw;
1792 	struct ieee80211_hdr *hdr;
1793 	int retval;
1794 	bool decrypt_error = false;
1795 	struct ath_rx_status rs;
1796 	enum ath9k_rx_qtype qtype;
1797 	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
1798 	int dma_type;
1799 	u8 rx_status_len = ah->caps.rx_status_len;
1800 	u64 tsf = 0;
1801 	u32 tsf_lower = 0;
1802 	unsigned long flags;
1803 
1804 	if (edma)
1805 		dma_type = DMA_BIDIRECTIONAL;
1806 	else
1807 		dma_type = DMA_FROM_DEVICE;
1808 
1809 	qtype = hp ? ATH9K_RX_QUEUE_HP : ATH9K_RX_QUEUE_LP;
1810 	spin_lock_bh(&sc->rx.rxbuflock);
1811 
1812 	tsf = ath9k_hw_gettsf64(ah);
1813 	tsf_lower = tsf & 0xffffffff;
1814 
1815 	do {
1816 		/* If handling rx interrupt and flush is in progress => exit */
1817 		if ((sc->sc_flags & SC_OP_RXFLUSH) && (flush == 0))
1818 			break;
1819 
1820 		memset(&rs, 0, sizeof(rs));
1821 		if (edma)
1822 			bf = ath_edma_get_next_rx_buf(sc, &rs, qtype);
1823 		else
1824 			bf = ath_get_next_rx_buf(sc, &rs);
1825 
1826 		if (!bf)
1827 			break;
1828 
1829 		skb = bf->bf_mpdu;
1830 		if (!skb)
1831 			continue;
1832 
1833 		/*
1834 		 * Take frame header from the first fragment and RX status from
1835 		 * the last one.
1836 		 */
1837 		if (sc->rx.frag)
1838 			hdr_skb = sc->rx.frag;
1839 		else
1840 			hdr_skb = skb;
1841 
1842 		hdr = (struct ieee80211_hdr *) (hdr_skb->data + rx_status_len);
1843 		rxs = IEEE80211_SKB_RXCB(hdr_skb);
1844 
1845 		ath_debug_stat_rx(sc, &rs);
1846 
1847 		/*
1848 		 * If we're asked to flush receive queue, directly
1849 		 * chain it back at the queue without processing it.
1850 		 */
1851 		if (flush)
1852 			goto requeue_drop_frag;
1853 
1854 		retval = ath9k_rx_skb_preprocess(common, hw, hdr, &rs,
1855 						 rxs, &decrypt_error);
1856 		if (retval)
1857 			goto requeue_drop_frag;
1858 
1859 		rxs->mactime = (tsf & ~0xffffffffULL) | rs.rs_tstamp;
1860 		if (rs.rs_tstamp > tsf_lower &&
1861 		    unlikely(rs.rs_tstamp - tsf_lower > 0x10000000))
1862 			rxs->mactime -= 0x100000000ULL;
1863 
1864 		if (rs.rs_tstamp < tsf_lower &&
1865 		    unlikely(tsf_lower - rs.rs_tstamp > 0x10000000))
1866 			rxs->mactime += 0x100000000ULL;
1867 
1868 		/* Ensure we always have an skb to requeue once we are done
1869 		 * processing the current buffer's skb */
1870 		requeue_skb = ath_rxbuf_alloc(common, common->rx_bufsize, GFP_ATOMIC);
1871 
1872 		/* If there is no memory we ignore the current RX'd frame,
1873 		 * tell hardware it can give us a new frame using the old
1874 		 * skb and put it at the tail of the sc->rx.rxbuf list for
1875 		 * processing. */
1876 		if (!requeue_skb)
1877 			goto requeue_drop_frag;
1878 
1879 		/* Unmap the frame */
1880 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
1881 				 common->rx_bufsize,
1882 				 dma_type);
1883 
1884 		skb_put(skb, rs.rs_datalen + ah->caps.rx_status_len);
1885 		if (ah->caps.rx_status_len)
1886 			skb_pull(skb, ah->caps.rx_status_len);
1887 
1888 		if (!rs.rs_more)
1889 			ath9k_rx_skb_postprocess(common, hdr_skb, &rs,
1890 						 rxs, decrypt_error);
1891 
1892 		/* We will now give hardware our shiny new allocated skb */
1893 		bf->bf_mpdu = requeue_skb;
1894 		bf->bf_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
1895 						 common->rx_bufsize,
1896 						 dma_type);
1897 		if (unlikely(dma_mapping_error(sc->dev,
1898 			  bf->bf_buf_addr))) {
1899 			dev_kfree_skb_any(requeue_skb);
1900 			bf->bf_mpdu = NULL;
1901 			bf->bf_buf_addr = 0;
1902 			ath_err(common, "dma_mapping_error() on RX\n");
1903 			ieee80211_rx(hw, skb);
1904 			break;
1905 		}
1906 
1907 		if (rs.rs_more) {
1908 			/*
1909 			 * rs_more indicates chained descriptors which can be
1910 			 * used to link buffers together for a sort of
1911 			 * scatter-gather operation.
1912 			 */
1913 			if (sc->rx.frag) {
1914 				/* too many fragments - cannot handle frame */
1915 				dev_kfree_skb_any(sc->rx.frag);
1916 				dev_kfree_skb_any(skb);
1917 				skb = NULL;
1918 			}
1919 			sc->rx.frag = skb;
1920 			goto requeue;
1921 		}
1922 
1923 		if (sc->rx.frag) {
1924 			int space = skb->len - skb_tailroom(hdr_skb);
1925 
1926 			sc->rx.frag = NULL;
1927 
1928 			if (pskb_expand_head(hdr_skb, 0, space, GFP_ATOMIC) < 0) {
1929 				dev_kfree_skb(skb);
1930 				goto requeue_drop_frag;
1931 			}
1932 
1933 			skb_copy_from_linear_data(skb, skb_put(hdr_skb, skb->len),
1934 						  skb->len);
1935 			dev_kfree_skb_any(skb);
1936 			skb = hdr_skb;
1937 		}
1938 
1939 		/*
1940 		 * change the default rx antenna if rx diversity chooses the
1941 		 * other antenna 3 times in a row.
1942 		 */
1943 		if (sc->rx.defant != rs.rs_antenna) {
1944 			if (++sc->rx.rxotherant >= 3)
1945 				ath_setdefantenna(sc, rs.rs_antenna);
1946 		} else {
1947 			sc->rx.rxotherant = 0;
1948 		}
1949 
1950 		if (rxs->flag & RX_FLAG_MMIC_STRIPPED)
1951 			skb_trim(skb, skb->len - 8);
1952 
1953 		spin_lock_irqsave(&sc->sc_pm_lock, flags);
1954 
1955 		if ((sc->ps_flags & (PS_WAIT_FOR_BEACON |
1956 					      PS_WAIT_FOR_CAB |
1957 					      PS_WAIT_FOR_PSPOLL_DATA)) ||
1958 						ath9k_check_auto_sleep(sc))
1959 			ath_rx_ps(sc, skb);
1960 		spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
1961 
1962 		if (ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB)
1963 			ath_ant_comb_scan(sc, &rs);
1964 
1965 		ieee80211_rx(hw, skb);
1966 
1967 requeue_drop_frag:
1968 		if (sc->rx.frag) {
1969 			dev_kfree_skb_any(sc->rx.frag);
1970 			sc->rx.frag = NULL;
1971 		}
1972 requeue:
1973 		if (edma) {
1974 			list_add_tail(&bf->list, &sc->rx.rxbuf);
1975 			ath_rx_edma_buf_link(sc, qtype);
1976 		} else {
1977 			list_move_tail(&bf->list, &sc->rx.rxbuf);
1978 			ath_rx_buf_link(sc, bf);
1979 			ath9k_hw_rxena(ah);
1980 		}
1981 	} while (1);
1982 
1983 	spin_unlock_bh(&sc->rx.rxbuflock);
1984 
1985 	return 0;
1986 }
1987