xref: /openbmc/linux/drivers/net/wireless/ath/ath9k/recv.c (revision bed3d9c0b71f9afbfec905cb6db3b9f16be29d4d)
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 	struct ath_buf *bf, *tbf;
173 
174 	if (list_empty(&sc->rx.rxbuf)) {
175 		ath_dbg(common, QUEUE, "No free rx buf available\n");
176 		return;
177 	}
178 
179 	list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list)
180 		if (!ath_rx_edma_buf_link(sc, qtype))
181 			break;
182 
183 }
184 
185 static void ath_rx_remove_buffer(struct ath_softc *sc,
186 				 enum ath9k_rx_qtype qtype)
187 {
188 	struct ath_buf *bf;
189 	struct ath_rx_edma *rx_edma;
190 	struct sk_buff *skb;
191 
192 	rx_edma = &sc->rx.rx_edma[qtype];
193 
194 	while ((skb = skb_dequeue(&rx_edma->rx_fifo)) != NULL) {
195 		bf = SKB_CB_ATHBUF(skb);
196 		BUG_ON(!bf);
197 		list_add_tail(&bf->list, &sc->rx.rxbuf);
198 	}
199 }
200 
201 static void ath_rx_edma_cleanup(struct ath_softc *sc)
202 {
203 	struct ath_hw *ah = sc->sc_ah;
204 	struct ath_common *common = ath9k_hw_common(ah);
205 	struct ath_buf *bf;
206 
207 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP);
208 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP);
209 
210 	list_for_each_entry(bf, &sc->rx.rxbuf, list) {
211 		if (bf->bf_mpdu) {
212 			dma_unmap_single(sc->dev, bf->bf_buf_addr,
213 					common->rx_bufsize,
214 					DMA_BIDIRECTIONAL);
215 			dev_kfree_skb_any(bf->bf_mpdu);
216 			bf->bf_buf_addr = 0;
217 			bf->bf_mpdu = NULL;
218 		}
219 	}
220 
221 	INIT_LIST_HEAD(&sc->rx.rxbuf);
222 
223 	kfree(sc->rx.rx_bufptr);
224 	sc->rx.rx_bufptr = NULL;
225 }
226 
227 static void ath_rx_edma_init_queue(struct ath_rx_edma *rx_edma, int size)
228 {
229 	skb_queue_head_init(&rx_edma->rx_fifo);
230 	rx_edma->rx_fifo_hwsize = size;
231 }
232 
233 static int ath_rx_edma_init(struct ath_softc *sc, int nbufs)
234 {
235 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
236 	struct ath_hw *ah = sc->sc_ah;
237 	struct sk_buff *skb;
238 	struct ath_buf *bf;
239 	int error = 0, i;
240 	u32 size;
241 
242 	ath9k_hw_set_rx_bufsize(ah, common->rx_bufsize -
243 				    ah->caps.rx_status_len);
244 
245 	ath_rx_edma_init_queue(&sc->rx.rx_edma[ATH9K_RX_QUEUE_LP],
246 			       ah->caps.rx_lp_qdepth);
247 	ath_rx_edma_init_queue(&sc->rx.rx_edma[ATH9K_RX_QUEUE_HP],
248 			       ah->caps.rx_hp_qdepth);
249 
250 	size = sizeof(struct ath_buf) * nbufs;
251 	bf = kzalloc(size, GFP_KERNEL);
252 	if (!bf)
253 		return -ENOMEM;
254 
255 	INIT_LIST_HEAD(&sc->rx.rxbuf);
256 	sc->rx.rx_bufptr = bf;
257 
258 	for (i = 0; i < nbufs; i++, bf++) {
259 		skb = ath_rxbuf_alloc(common, common->rx_bufsize, GFP_KERNEL);
260 		if (!skb) {
261 			error = -ENOMEM;
262 			goto rx_init_fail;
263 		}
264 
265 		memset(skb->data, 0, common->rx_bufsize);
266 		bf->bf_mpdu = skb;
267 
268 		bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
269 						 common->rx_bufsize,
270 						 DMA_BIDIRECTIONAL);
271 		if (unlikely(dma_mapping_error(sc->dev,
272 						bf->bf_buf_addr))) {
273 				dev_kfree_skb_any(skb);
274 				bf->bf_mpdu = NULL;
275 				bf->bf_buf_addr = 0;
276 				ath_err(common,
277 					"dma_mapping_error() on RX init\n");
278 				error = -ENOMEM;
279 				goto rx_init_fail;
280 		}
281 
282 		list_add_tail(&bf->list, &sc->rx.rxbuf);
283 	}
284 
285 	return 0;
286 
287 rx_init_fail:
288 	ath_rx_edma_cleanup(sc);
289 	return error;
290 }
291 
292 static void ath_edma_start_recv(struct ath_softc *sc)
293 {
294 	spin_lock_bh(&sc->rx.rxbuflock);
295 
296 	ath9k_hw_rxena(sc->sc_ah);
297 
298 	ath_rx_addbuffer_edma(sc, ATH9K_RX_QUEUE_HP,
299 			      sc->rx.rx_edma[ATH9K_RX_QUEUE_HP].rx_fifo_hwsize);
300 
301 	ath_rx_addbuffer_edma(sc, ATH9K_RX_QUEUE_LP,
302 			      sc->rx.rx_edma[ATH9K_RX_QUEUE_LP].rx_fifo_hwsize);
303 
304 	ath_opmode_init(sc);
305 
306 	ath9k_hw_startpcureceive(sc->sc_ah, (sc->sc_flags & SC_OP_OFFCHANNEL));
307 
308 	spin_unlock_bh(&sc->rx.rxbuflock);
309 }
310 
311 static void ath_edma_stop_recv(struct ath_softc *sc)
312 {
313 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_HP);
314 	ath_rx_remove_buffer(sc, ATH9K_RX_QUEUE_LP);
315 }
316 
317 int ath_rx_init(struct ath_softc *sc, int nbufs)
318 {
319 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
320 	struct sk_buff *skb;
321 	struct ath_buf *bf;
322 	int error = 0;
323 
324 	spin_lock_init(&sc->sc_pcu_lock);
325 	sc->sc_flags &= ~SC_OP_RXFLUSH;
326 	spin_lock_init(&sc->rx.rxbuflock);
327 
328 	common->rx_bufsize = IEEE80211_MAX_MPDU_LEN / 2 +
329 			     sc->sc_ah->caps.rx_status_len;
330 
331 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
332 		return ath_rx_edma_init(sc, nbufs);
333 	} else {
334 		ath_dbg(common, CONFIG, "cachelsz %u rxbufsize %u\n",
335 			common->cachelsz, common->rx_bufsize);
336 
337 		/* Initialize rx descriptors */
338 
339 		error = ath_descdma_setup(sc, &sc->rx.rxdma, &sc->rx.rxbuf,
340 				"rx", nbufs, 1, 0);
341 		if (error != 0) {
342 			ath_err(common,
343 				"failed to allocate rx descriptors: %d\n",
344 				error);
345 			goto err;
346 		}
347 
348 		list_for_each_entry(bf, &sc->rx.rxbuf, list) {
349 			skb = ath_rxbuf_alloc(common, common->rx_bufsize,
350 					      GFP_KERNEL);
351 			if (skb == NULL) {
352 				error = -ENOMEM;
353 				goto err;
354 			}
355 
356 			bf->bf_mpdu = skb;
357 			bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
358 					common->rx_bufsize,
359 					DMA_FROM_DEVICE);
360 			if (unlikely(dma_mapping_error(sc->dev,
361 							bf->bf_buf_addr))) {
362 				dev_kfree_skb_any(skb);
363 				bf->bf_mpdu = NULL;
364 				bf->bf_buf_addr = 0;
365 				ath_err(common,
366 					"dma_mapping_error() on RX init\n");
367 				error = -ENOMEM;
368 				goto err;
369 			}
370 		}
371 		sc->rx.rxlink = NULL;
372 	}
373 
374 err:
375 	if (error)
376 		ath_rx_cleanup(sc);
377 
378 	return error;
379 }
380 
381 void ath_rx_cleanup(struct ath_softc *sc)
382 {
383 	struct ath_hw *ah = sc->sc_ah;
384 	struct ath_common *common = ath9k_hw_common(ah);
385 	struct sk_buff *skb;
386 	struct ath_buf *bf;
387 
388 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
389 		ath_rx_edma_cleanup(sc);
390 		return;
391 	} else {
392 		list_for_each_entry(bf, &sc->rx.rxbuf, list) {
393 			skb = bf->bf_mpdu;
394 			if (skb) {
395 				dma_unmap_single(sc->dev, bf->bf_buf_addr,
396 						common->rx_bufsize,
397 						DMA_FROM_DEVICE);
398 				dev_kfree_skb(skb);
399 				bf->bf_buf_addr = 0;
400 				bf->bf_mpdu = NULL;
401 			}
402 		}
403 
404 		if (sc->rx.rxdma.dd_desc_len != 0)
405 			ath_descdma_cleanup(sc, &sc->rx.rxdma, &sc->rx.rxbuf);
406 	}
407 }
408 
409 /*
410  * Calculate the receive filter according to the
411  * operating mode and state:
412  *
413  * o always accept unicast, broadcast, and multicast traffic
414  * o maintain current state of phy error reception (the hal
415  *   may enable phy error frames for noise immunity work)
416  * o probe request frames are accepted only when operating in
417  *   hostap, adhoc, or monitor modes
418  * o enable promiscuous mode according to the interface state
419  * o accept beacons:
420  *   - when operating in adhoc mode so the 802.11 layer creates
421  *     node table entries for peers,
422  *   - when operating in station mode for collecting rssi data when
423  *     the station is otherwise quiet, or
424  *   - when operating as a repeater so we see repeater-sta beacons
425  *   - when scanning
426  */
427 
428 u32 ath_calcrxfilter(struct ath_softc *sc)
429 {
430 	u32 rfilt;
431 
432 	rfilt = ATH9K_RX_FILTER_UCAST | ATH9K_RX_FILTER_BCAST
433 		| ATH9K_RX_FILTER_MCAST;
434 
435 	if (sc->rx.rxfilter & FIF_PROBE_REQ)
436 		rfilt |= ATH9K_RX_FILTER_PROBEREQ;
437 
438 	/*
439 	 * Set promiscuous mode when FIF_PROMISC_IN_BSS is enabled for station
440 	 * mode interface or when in monitor mode. AP mode does not need this
441 	 * since it receives all in-BSS frames anyway.
442 	 */
443 	if (sc->sc_ah->is_monitoring)
444 		rfilt |= ATH9K_RX_FILTER_PROM;
445 
446 	if (sc->rx.rxfilter & FIF_CONTROL)
447 		rfilt |= ATH9K_RX_FILTER_CONTROL;
448 
449 	if ((sc->sc_ah->opmode == NL80211_IFTYPE_STATION) &&
450 	    (sc->nvifs <= 1) &&
451 	    !(sc->rx.rxfilter & FIF_BCN_PRBRESP_PROMISC))
452 		rfilt |= ATH9K_RX_FILTER_MYBEACON;
453 	else
454 		rfilt |= ATH9K_RX_FILTER_BEACON;
455 
456 	if ((sc->sc_ah->opmode == NL80211_IFTYPE_AP) ||
457 	    (sc->rx.rxfilter & FIF_PSPOLL))
458 		rfilt |= ATH9K_RX_FILTER_PSPOLL;
459 
460 	if (conf_is_ht(&sc->hw->conf))
461 		rfilt |= ATH9K_RX_FILTER_COMP_BAR;
462 
463 	if (sc->nvifs > 1 || (sc->rx.rxfilter & FIF_OTHER_BSS)) {
464 		/* The following may also be needed for other older chips */
465 		if (sc->sc_ah->hw_version.macVersion == AR_SREV_VERSION_9160)
466 			rfilt |= ATH9K_RX_FILTER_PROM;
467 		rfilt |= ATH9K_RX_FILTER_MCAST_BCAST_ALL;
468 	}
469 
470 	return rfilt;
471 
472 }
473 
474 int ath_startrecv(struct ath_softc *sc)
475 {
476 	struct ath_hw *ah = sc->sc_ah;
477 	struct ath_buf *bf, *tbf;
478 
479 	if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
480 		ath_edma_start_recv(sc);
481 		return 0;
482 	}
483 
484 	spin_lock_bh(&sc->rx.rxbuflock);
485 	if (list_empty(&sc->rx.rxbuf))
486 		goto start_recv;
487 
488 	sc->rx.rxlink = NULL;
489 	list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list) {
490 		ath_rx_buf_link(sc, bf);
491 	}
492 
493 	/* We could have deleted elements so the list may be empty now */
494 	if (list_empty(&sc->rx.rxbuf))
495 		goto start_recv;
496 
497 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
498 	ath9k_hw_putrxbuf(ah, bf->bf_daddr);
499 	ath9k_hw_rxena(ah);
500 
501 start_recv:
502 	ath_opmode_init(sc);
503 	ath9k_hw_startpcureceive(ah, (sc->sc_flags & SC_OP_OFFCHANNEL));
504 
505 	spin_unlock_bh(&sc->rx.rxbuflock);
506 
507 	return 0;
508 }
509 
510 bool ath_stoprecv(struct ath_softc *sc)
511 {
512 	struct ath_hw *ah = sc->sc_ah;
513 	bool stopped, reset = false;
514 
515 	spin_lock_bh(&sc->rx.rxbuflock);
516 	ath9k_hw_abortpcurecv(ah);
517 	ath9k_hw_setrxfilter(ah, 0);
518 	stopped = ath9k_hw_stopdmarecv(ah, &reset);
519 
520 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
521 		ath_edma_stop_recv(sc);
522 	else
523 		sc->rx.rxlink = NULL;
524 	spin_unlock_bh(&sc->rx.rxbuflock);
525 
526 	if (!(ah->ah_flags & AH_UNPLUGGED) &&
527 	    unlikely(!stopped)) {
528 		ath_err(ath9k_hw_common(sc->sc_ah),
529 			"Could not stop RX, we could be "
530 			"confusing the DMA engine when we start RX up\n");
531 		ATH_DBG_WARN_ON_ONCE(!stopped);
532 	}
533 	return stopped && !reset;
534 }
535 
536 void ath_flushrecv(struct ath_softc *sc)
537 {
538 	sc->sc_flags |= SC_OP_RXFLUSH;
539 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
540 		ath_rx_tasklet(sc, 1, true);
541 	ath_rx_tasklet(sc, 1, false);
542 	sc->sc_flags &= ~SC_OP_RXFLUSH;
543 }
544 
545 static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
546 {
547 	/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */
548 	struct ieee80211_mgmt *mgmt;
549 	u8 *pos, *end, id, elen;
550 	struct ieee80211_tim_ie *tim;
551 
552 	mgmt = (struct ieee80211_mgmt *)skb->data;
553 	pos = mgmt->u.beacon.variable;
554 	end = skb->data + skb->len;
555 
556 	while (pos + 2 < end) {
557 		id = *pos++;
558 		elen = *pos++;
559 		if (pos + elen > end)
560 			break;
561 
562 		if (id == WLAN_EID_TIM) {
563 			if (elen < sizeof(*tim))
564 				break;
565 			tim = (struct ieee80211_tim_ie *) pos;
566 			if (tim->dtim_count != 0)
567 				break;
568 			return tim->bitmap_ctrl & 0x01;
569 		}
570 
571 		pos += elen;
572 	}
573 
574 	return false;
575 }
576 
577 static void ath_rx_ps_beacon(struct ath_softc *sc, struct sk_buff *skb)
578 {
579 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
580 
581 	if (skb->len < 24 + 8 + 2 + 2)
582 		return;
583 
584 	sc->ps_flags &= ~PS_WAIT_FOR_BEACON;
585 
586 	if (sc->ps_flags & PS_BEACON_SYNC) {
587 		sc->ps_flags &= ~PS_BEACON_SYNC;
588 		ath_dbg(common, PS,
589 			"Reconfigure Beacon timers based on timestamp from the AP\n");
590 		ath_set_beacon(sc);
591 	}
592 
593 	if (ath_beacon_dtim_pending_cab(skb)) {
594 		/*
595 		 * Remain awake waiting for buffered broadcast/multicast
596 		 * frames. If the last broadcast/multicast frame is not
597 		 * received properly, the next beacon frame will work as
598 		 * a backup trigger for returning into NETWORK SLEEP state,
599 		 * so we are waiting for it as well.
600 		 */
601 		ath_dbg(common, PS,
602 			"Received DTIM beacon indicating buffered broadcast/multicast frame(s)\n");
603 		sc->ps_flags |= PS_WAIT_FOR_CAB | PS_WAIT_FOR_BEACON;
604 		return;
605 	}
606 
607 	if (sc->ps_flags & PS_WAIT_FOR_CAB) {
608 		/*
609 		 * This can happen if a broadcast frame is dropped or the AP
610 		 * fails to send a frame indicating that all CAB frames have
611 		 * been delivered.
612 		 */
613 		sc->ps_flags &= ~PS_WAIT_FOR_CAB;
614 		ath_dbg(common, PS, "PS wait for CAB frames timed out\n");
615 	}
616 }
617 
618 static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb, bool mybeacon)
619 {
620 	struct ieee80211_hdr *hdr;
621 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
622 
623 	hdr = (struct ieee80211_hdr *)skb->data;
624 
625 	/* Process Beacon and CAB receive in PS state */
626 	if (((sc->ps_flags & PS_WAIT_FOR_BEACON) || ath9k_check_auto_sleep(sc))
627 	    && mybeacon)
628 		ath_rx_ps_beacon(sc, skb);
629 	else if ((sc->ps_flags & PS_WAIT_FOR_CAB) &&
630 		 (ieee80211_is_data(hdr->frame_control) ||
631 		  ieee80211_is_action(hdr->frame_control)) &&
632 		 is_multicast_ether_addr(hdr->addr1) &&
633 		 !ieee80211_has_moredata(hdr->frame_control)) {
634 		/*
635 		 * No more broadcast/multicast frames to be received at this
636 		 * point.
637 		 */
638 		sc->ps_flags &= ~(PS_WAIT_FOR_CAB | PS_WAIT_FOR_BEACON);
639 		ath_dbg(common, PS,
640 			"All PS CAB frames received, back to sleep\n");
641 	} else if ((sc->ps_flags & PS_WAIT_FOR_PSPOLL_DATA) &&
642 		   !is_multicast_ether_addr(hdr->addr1) &&
643 		   !ieee80211_has_morefrags(hdr->frame_control)) {
644 		sc->ps_flags &= ~PS_WAIT_FOR_PSPOLL_DATA;
645 		ath_dbg(common, PS,
646 			"Going back to sleep after having received PS-Poll data (0x%lx)\n",
647 			sc->ps_flags & (PS_WAIT_FOR_BEACON |
648 					PS_WAIT_FOR_CAB |
649 					PS_WAIT_FOR_PSPOLL_DATA |
650 					PS_WAIT_FOR_TX_ACK));
651 	}
652 }
653 
654 static bool ath_edma_get_buffers(struct ath_softc *sc,
655 				 enum ath9k_rx_qtype qtype,
656 				 struct ath_rx_status *rs,
657 				 struct ath_buf **dest)
658 {
659 	struct ath_rx_edma *rx_edma = &sc->rx.rx_edma[qtype];
660 	struct ath_hw *ah = sc->sc_ah;
661 	struct ath_common *common = ath9k_hw_common(ah);
662 	struct sk_buff *skb;
663 	struct ath_buf *bf;
664 	int ret;
665 
666 	skb = skb_peek(&rx_edma->rx_fifo);
667 	if (!skb)
668 		return false;
669 
670 	bf = SKB_CB_ATHBUF(skb);
671 	BUG_ON(!bf);
672 
673 	dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
674 				common->rx_bufsize, DMA_FROM_DEVICE);
675 
676 	ret = ath9k_hw_process_rxdesc_edma(ah, rs, skb->data);
677 	if (ret == -EINPROGRESS) {
678 		/*let device gain the buffer again*/
679 		dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
680 				common->rx_bufsize, DMA_FROM_DEVICE);
681 		return false;
682 	}
683 
684 	__skb_unlink(skb, &rx_edma->rx_fifo);
685 	if (ret == -EINVAL) {
686 		/* corrupt descriptor, skip this one and the following one */
687 		list_add_tail(&bf->list, &sc->rx.rxbuf);
688 		ath_rx_edma_buf_link(sc, qtype);
689 
690 		skb = skb_peek(&rx_edma->rx_fifo);
691 		if (skb) {
692 			bf = SKB_CB_ATHBUF(skb);
693 			BUG_ON(!bf);
694 
695 			__skb_unlink(skb, &rx_edma->rx_fifo);
696 			list_add_tail(&bf->list, &sc->rx.rxbuf);
697 			ath_rx_edma_buf_link(sc, qtype);
698 		} else {
699 			bf = NULL;
700 		}
701 	}
702 
703 	*dest = bf;
704 	return true;
705 }
706 
707 static struct ath_buf *ath_edma_get_next_rx_buf(struct ath_softc *sc,
708 						struct ath_rx_status *rs,
709 						enum ath9k_rx_qtype qtype)
710 {
711 	struct ath_buf *bf = NULL;
712 
713 	while (ath_edma_get_buffers(sc, qtype, rs, &bf)) {
714 		if (!bf)
715 			continue;
716 
717 		return bf;
718 	}
719 	return NULL;
720 }
721 
722 static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc,
723 					   struct ath_rx_status *rs)
724 {
725 	struct ath_hw *ah = sc->sc_ah;
726 	struct ath_common *common = ath9k_hw_common(ah);
727 	struct ath_desc *ds;
728 	struct ath_buf *bf;
729 	int ret;
730 
731 	if (list_empty(&sc->rx.rxbuf)) {
732 		sc->rx.rxlink = NULL;
733 		return NULL;
734 	}
735 
736 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
737 	ds = bf->bf_desc;
738 
739 	/*
740 	 * Must provide the virtual address of the current
741 	 * descriptor, the physical address, and the virtual
742 	 * address of the next descriptor in the h/w chain.
743 	 * This allows the HAL to look ahead to see if the
744 	 * hardware is done with a descriptor by checking the
745 	 * done bit in the following descriptor and the address
746 	 * of the current descriptor the DMA engine is working
747 	 * on.  All this is necessary because of our use of
748 	 * a self-linked list to avoid rx overruns.
749 	 */
750 	ret = ath9k_hw_rxprocdesc(ah, ds, rs);
751 	if (ret == -EINPROGRESS) {
752 		struct ath_rx_status trs;
753 		struct ath_buf *tbf;
754 		struct ath_desc *tds;
755 
756 		memset(&trs, 0, sizeof(trs));
757 		if (list_is_last(&bf->list, &sc->rx.rxbuf)) {
758 			sc->rx.rxlink = NULL;
759 			return NULL;
760 		}
761 
762 		tbf = list_entry(bf->list.next, struct ath_buf, list);
763 
764 		/*
765 		 * On some hardware the descriptor status words could
766 		 * get corrupted, including the done bit. Because of
767 		 * this, check if the next descriptor's done bit is
768 		 * set or not.
769 		 *
770 		 * If the next descriptor's done bit is set, the current
771 		 * descriptor has been corrupted. Force s/w to discard
772 		 * this descriptor and continue...
773 		 */
774 
775 		tds = tbf->bf_desc;
776 		ret = ath9k_hw_rxprocdesc(ah, tds, &trs);
777 		if (ret == -EINPROGRESS)
778 			return NULL;
779 	}
780 
781 	if (!bf->bf_mpdu)
782 		return bf;
783 
784 	/*
785 	 * Synchronize the DMA transfer with CPU before
786 	 * 1. accessing the frame
787 	 * 2. requeueing the same buffer to h/w
788 	 */
789 	dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
790 			common->rx_bufsize,
791 			DMA_FROM_DEVICE);
792 
793 	return bf;
794 }
795 
796 /* Assumes you've already done the endian to CPU conversion */
797 static bool ath9k_rx_accept(struct ath_common *common,
798 			    struct ieee80211_hdr *hdr,
799 			    struct ieee80211_rx_status *rxs,
800 			    struct ath_rx_status *rx_stats,
801 			    bool *decrypt_error)
802 {
803 	struct ath_softc *sc = (struct ath_softc *) common->priv;
804 	bool is_mc, is_valid_tkip, strip_mic, mic_error;
805 	struct ath_hw *ah = common->ah;
806 	__le16 fc;
807 	u8 rx_status_len = ah->caps.rx_status_len;
808 
809 	fc = hdr->frame_control;
810 
811 	is_mc = !!is_multicast_ether_addr(hdr->addr1);
812 	is_valid_tkip = rx_stats->rs_keyix != ATH9K_RXKEYIX_INVALID &&
813 		test_bit(rx_stats->rs_keyix, common->tkip_keymap);
814 	strip_mic = is_valid_tkip && ieee80211_is_data(fc) &&
815 		ieee80211_has_protected(fc) &&
816 		!(rx_stats->rs_status &
817 		(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_CRC | ATH9K_RXERR_MIC |
818 		 ATH9K_RXERR_KEYMISS));
819 
820 	/*
821 	 * Key miss events are only relevant for pairwise keys where the
822 	 * descriptor does contain a valid key index. This has been observed
823 	 * mostly with CCMP encryption.
824 	 */
825 	if (rx_stats->rs_keyix == ATH9K_RXKEYIX_INVALID ||
826 	    !test_bit(rx_stats->rs_keyix, common->ccmp_keymap))
827 		rx_stats->rs_status &= ~ATH9K_RXERR_KEYMISS;
828 
829 	if (!rx_stats->rs_datalen) {
830 		RX_STAT_INC(rx_len_err);
831 		return false;
832 	}
833 
834         /*
835          * rs_status follows rs_datalen so if rs_datalen is too large
836          * we can take a hint that hardware corrupted it, so ignore
837          * those frames.
838          */
839 	if (rx_stats->rs_datalen > (common->rx_bufsize - rx_status_len)) {
840 		RX_STAT_INC(rx_len_err);
841 		return false;
842 	}
843 
844 	/* Only use error bits from the last fragment */
845 	if (rx_stats->rs_more)
846 		return true;
847 
848 	mic_error = is_valid_tkip && !ieee80211_is_ctl(fc) &&
849 		!ieee80211_has_morefrags(fc) &&
850 		!(le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG) &&
851 		(rx_stats->rs_status & ATH9K_RXERR_MIC);
852 
853 	/*
854 	 * The rx_stats->rs_status will not be set until the end of the
855 	 * chained descriptors so it can be ignored if rs_more is set. The
856 	 * rs_more will be false at the last element of the chained
857 	 * descriptors.
858 	 */
859 	if (rx_stats->rs_status != 0) {
860 		u8 status_mask;
861 
862 		if (rx_stats->rs_status & ATH9K_RXERR_CRC) {
863 			rxs->flag |= RX_FLAG_FAILED_FCS_CRC;
864 			mic_error = false;
865 		}
866 		if (rx_stats->rs_status & ATH9K_RXERR_PHY)
867 			return false;
868 
869 		if ((rx_stats->rs_status & ATH9K_RXERR_DECRYPT) ||
870 		    (!is_mc && (rx_stats->rs_status & ATH9K_RXERR_KEYMISS))) {
871 			*decrypt_error = true;
872 			mic_error = false;
873 		}
874 
875 		/*
876 		 * Reject error frames with the exception of
877 		 * decryption and MIC failures. For monitor mode,
878 		 * we also ignore the CRC error.
879 		 */
880 		status_mask = ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
881 			      ATH9K_RXERR_KEYMISS;
882 
883 		if (ah->is_monitoring && (sc->rx.rxfilter & FIF_FCSFAIL))
884 			status_mask |= ATH9K_RXERR_CRC;
885 
886 		if (rx_stats->rs_status & ~status_mask)
887 			return false;
888 	}
889 
890 	/*
891 	 * For unicast frames the MIC error bit can have false positives,
892 	 * so all MIC error reports need to be validated in software.
893 	 * False negatives are not common, so skip software verification
894 	 * if the hardware considers the MIC valid.
895 	 */
896 	if (strip_mic)
897 		rxs->flag |= RX_FLAG_MMIC_STRIPPED;
898 	else if (is_mc && mic_error)
899 		rxs->flag |= RX_FLAG_MMIC_ERROR;
900 
901 	return true;
902 }
903 
904 static int ath9k_process_rate(struct ath_common *common,
905 			      struct ieee80211_hw *hw,
906 			      struct ath_rx_status *rx_stats,
907 			      struct ieee80211_rx_status *rxs)
908 {
909 	struct ieee80211_supported_band *sband;
910 	enum ieee80211_band band;
911 	unsigned int i = 0;
912 	struct ath_softc __maybe_unused *sc = common->priv;
913 
914 	band = hw->conf.channel->band;
915 	sband = hw->wiphy->bands[band];
916 
917 	if (rx_stats->rs_rate & 0x80) {
918 		/* HT rate */
919 		rxs->flag |= RX_FLAG_HT;
920 		if (rx_stats->rs_flags & ATH9K_RX_2040)
921 			rxs->flag |= RX_FLAG_40MHZ;
922 		if (rx_stats->rs_flags & ATH9K_RX_GI)
923 			rxs->flag |= RX_FLAG_SHORT_GI;
924 		rxs->rate_idx = rx_stats->rs_rate & 0x7f;
925 		return 0;
926 	}
927 
928 	for (i = 0; i < sband->n_bitrates; i++) {
929 		if (sband->bitrates[i].hw_value == rx_stats->rs_rate) {
930 			rxs->rate_idx = i;
931 			return 0;
932 		}
933 		if (sband->bitrates[i].hw_value_short == rx_stats->rs_rate) {
934 			rxs->flag |= RX_FLAG_SHORTPRE;
935 			rxs->rate_idx = i;
936 			return 0;
937 		}
938 	}
939 
940 	/*
941 	 * No valid hardware bitrate found -- we should not get here
942 	 * because hardware has already validated this frame as OK.
943 	 */
944 	ath_dbg(common, ANY,
945 		"unsupported hw bitrate detected 0x%02x using 1 Mbit\n",
946 		rx_stats->rs_rate);
947 	RX_STAT_INC(rx_rate_err);
948 	return -EINVAL;
949 }
950 
951 static void ath9k_process_rssi(struct ath_common *common,
952 			       struct ieee80211_hw *hw,
953 			       struct ieee80211_hdr *hdr,
954 			       struct ath_rx_status *rx_stats)
955 {
956 	struct ath_softc *sc = hw->priv;
957 	struct ath_hw *ah = common->ah;
958 	int last_rssi;
959 	int rssi = rx_stats->rs_rssi;
960 
961 	if (!rx_stats->is_mybeacon ||
962 	    ((ah->opmode != NL80211_IFTYPE_STATION) &&
963 	     (ah->opmode != NL80211_IFTYPE_ADHOC)))
964 		return;
965 
966 	if (rx_stats->rs_rssi != ATH9K_RSSI_BAD && !rx_stats->rs_moreaggr)
967 		ATH_RSSI_LPF(sc->last_rssi, rx_stats->rs_rssi);
968 
969 	last_rssi = sc->last_rssi;
970 	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
971 		rssi = ATH_EP_RND(last_rssi, ATH_RSSI_EP_MULTIPLIER);
972 	if (rssi < 0)
973 		rssi = 0;
974 
975 	/* Update Beacon RSSI, this is used by ANI. */
976 	ah->stats.avgbrssi = rssi;
977 }
978 
979 /*
980  * For Decrypt or Demic errors, we only mark packet status here and always push
981  * up the frame up to let mac80211 handle the actual error case, be it no
982  * decryption key or real decryption error. This let us keep statistics there.
983  */
984 static int ath9k_rx_skb_preprocess(struct ath_common *common,
985 				   struct ieee80211_hw *hw,
986 				   struct ieee80211_hdr *hdr,
987 				   struct ath_rx_status *rx_stats,
988 				   struct ieee80211_rx_status *rx_status,
989 				   bool *decrypt_error)
990 {
991 	struct ath_hw *ah = common->ah;
992 
993 	/*
994 	 * everything but the rate is checked here, the rate check is done
995 	 * separately to avoid doing two lookups for a rate for each frame.
996 	 */
997 	if (!ath9k_rx_accept(common, hdr, rx_status, rx_stats, decrypt_error))
998 		return -EINVAL;
999 
1000 	/* Only use status info from the last fragment */
1001 	if (rx_stats->rs_more)
1002 		return 0;
1003 
1004 	ath9k_process_rssi(common, hw, hdr, rx_stats);
1005 
1006 	if (ath9k_process_rate(common, hw, rx_stats, rx_status))
1007 		return -EINVAL;
1008 
1009 	rx_status->band = hw->conf.channel->band;
1010 	rx_status->freq = hw->conf.channel->center_freq;
1011 	rx_status->signal = ah->noise + rx_stats->rs_rssi;
1012 	rx_status->antenna = rx_stats->rs_antenna;
1013 	rx_status->flag |= RX_FLAG_MACTIME_MPDU;
1014 	if (rx_stats->rs_moreaggr)
1015 		rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL;
1016 
1017 	return 0;
1018 }
1019 
1020 static void ath9k_rx_skb_postprocess(struct ath_common *common,
1021 				     struct sk_buff *skb,
1022 				     struct ath_rx_status *rx_stats,
1023 				     struct ieee80211_rx_status *rxs,
1024 				     bool decrypt_error)
1025 {
1026 	struct ath_hw *ah = common->ah;
1027 	struct ieee80211_hdr *hdr;
1028 	int hdrlen, padpos, padsize;
1029 	u8 keyix;
1030 	__le16 fc;
1031 
1032 	/* see if any padding is done by the hw and remove it */
1033 	hdr = (struct ieee80211_hdr *) skb->data;
1034 	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
1035 	fc = hdr->frame_control;
1036 	padpos = ath9k_cmn_padpos(hdr->frame_control);
1037 
1038 	/* The MAC header is padded to have 32-bit boundary if the
1039 	 * packet payload is non-zero. The general calculation for
1040 	 * padsize would take into account odd header lengths:
1041 	 * padsize = (4 - padpos % 4) % 4; However, since only
1042 	 * even-length headers are used, padding can only be 0 or 2
1043 	 * bytes and we can optimize this a bit. In addition, we must
1044 	 * not try to remove padding from short control frames that do
1045 	 * not have payload. */
1046 	padsize = padpos & 3;
1047 	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
1048 		memmove(skb->data + padsize, skb->data, padpos);
1049 		skb_pull(skb, padsize);
1050 	}
1051 
1052 	keyix = rx_stats->rs_keyix;
1053 
1054 	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error &&
1055 	    ieee80211_has_protected(fc)) {
1056 		rxs->flag |= RX_FLAG_DECRYPTED;
1057 	} else if (ieee80211_has_protected(fc)
1058 		   && !decrypt_error && skb->len >= hdrlen + 4) {
1059 		keyix = skb->data[hdrlen + 3] >> 6;
1060 
1061 		if (test_bit(keyix, common->keymap))
1062 			rxs->flag |= RX_FLAG_DECRYPTED;
1063 	}
1064 	if (ah->sw_mgmt_crypto &&
1065 	    (rxs->flag & RX_FLAG_DECRYPTED) &&
1066 	    ieee80211_is_mgmt(fc))
1067 		/* Use software decrypt for management frames. */
1068 		rxs->flag &= ~RX_FLAG_DECRYPTED;
1069 }
1070 
1071 static void ath_lnaconf_alt_good_scan(struct ath_ant_comb *antcomb,
1072 				      struct ath_hw_antcomb_conf ant_conf,
1073 				      int main_rssi_avg)
1074 {
1075 	antcomb->quick_scan_cnt = 0;
1076 
1077 	if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA2)
1078 		antcomb->rssi_lna2 = main_rssi_avg;
1079 	else if (ant_conf.main_lna_conf == ATH_ANT_DIV_COMB_LNA1)
1080 		antcomb->rssi_lna1 = main_rssi_avg;
1081 
1082 	switch ((ant_conf.main_lna_conf << 4) | ant_conf.alt_lna_conf) {
1083 	case 0x10: /* LNA2 A-B */
1084 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1085 		antcomb->first_quick_scan_conf =
1086 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1087 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
1088 		break;
1089 	case 0x20: /* LNA1 A-B */
1090 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1091 		antcomb->first_quick_scan_conf =
1092 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1093 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
1094 		break;
1095 	case 0x21: /* LNA1 LNA2 */
1096 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA2;
1097 		antcomb->first_quick_scan_conf =
1098 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1099 		antcomb->second_quick_scan_conf =
1100 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1101 		break;
1102 	case 0x12: /* LNA2 LNA1 */
1103 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1;
1104 		antcomb->first_quick_scan_conf =
1105 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1106 		antcomb->second_quick_scan_conf =
1107 			ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1108 		break;
1109 	case 0x13: /* LNA2 A+B */
1110 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1111 		antcomb->first_quick_scan_conf =
1112 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1113 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA1;
1114 		break;
1115 	case 0x23: /* LNA1 A+B */
1116 		antcomb->main_conf = ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1117 		antcomb->first_quick_scan_conf =
1118 			ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1119 		antcomb->second_quick_scan_conf = ATH_ANT_DIV_COMB_LNA2;
1120 		break;
1121 	default:
1122 		break;
1123 	}
1124 }
1125 
1126 static void ath_select_ant_div_from_quick_scan(struct ath_ant_comb *antcomb,
1127 				struct ath_hw_antcomb_conf *div_ant_conf,
1128 				int main_rssi_avg, int alt_rssi_avg,
1129 				int alt_ratio)
1130 {
1131 	/* alt_good */
1132 	switch (antcomb->quick_scan_cnt) {
1133 	case 0:
1134 		/* set alt to main, and alt to first conf */
1135 		div_ant_conf->main_lna_conf = antcomb->main_conf;
1136 		div_ant_conf->alt_lna_conf = antcomb->first_quick_scan_conf;
1137 		break;
1138 	case 1:
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->second_quick_scan_conf;
1142 		antcomb->rssi_first = main_rssi_avg;
1143 		antcomb->rssi_second = alt_rssi_avg;
1144 
1145 		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
1146 			/* main is LNA1 */
1147 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1148 						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
1149 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1150 						main_rssi_avg, alt_rssi_avg,
1151 						antcomb->total_pkt_count))
1152 				antcomb->first_ratio = true;
1153 			else
1154 				antcomb->first_ratio = false;
1155 		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
1156 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1157 						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
1158 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1159 						main_rssi_avg, alt_rssi_avg,
1160 						antcomb->total_pkt_count))
1161 				antcomb->first_ratio = true;
1162 			else
1163 				antcomb->first_ratio = false;
1164 		} else {
1165 			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
1166 			    (alt_rssi_avg > main_rssi_avg +
1167 			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
1168 			    (alt_rssi_avg > main_rssi_avg)) &&
1169 			    (antcomb->total_pkt_count > 50))
1170 				antcomb->first_ratio = true;
1171 			else
1172 				antcomb->first_ratio = false;
1173 		}
1174 		break;
1175 	case 2:
1176 		antcomb->alt_good = false;
1177 		antcomb->scan_not_start = false;
1178 		antcomb->scan = false;
1179 		antcomb->rssi_first = main_rssi_avg;
1180 		antcomb->rssi_third = alt_rssi_avg;
1181 
1182 		if (antcomb->second_quick_scan_conf == ATH_ANT_DIV_COMB_LNA1)
1183 			antcomb->rssi_lna1 = alt_rssi_avg;
1184 		else if (antcomb->second_quick_scan_conf ==
1185 			 ATH_ANT_DIV_COMB_LNA2)
1186 			antcomb->rssi_lna2 = alt_rssi_avg;
1187 		else if (antcomb->second_quick_scan_conf ==
1188 			 ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2) {
1189 			if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2)
1190 				antcomb->rssi_lna2 = main_rssi_avg;
1191 			else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1)
1192 				antcomb->rssi_lna1 = main_rssi_avg;
1193 		}
1194 
1195 		if (antcomb->rssi_lna2 > antcomb->rssi_lna1 +
1196 		    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)
1197 			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
1198 		else
1199 			div_ant_conf->main_lna_conf = ATH_ANT_DIV_COMB_LNA1;
1200 
1201 		if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) {
1202 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1203 						ATH_ANT_DIV_COMB_LNA1_DELTA_HI,
1204 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1205 						main_rssi_avg, alt_rssi_avg,
1206 						antcomb->total_pkt_count))
1207 				antcomb->second_ratio = true;
1208 			else
1209 				antcomb->second_ratio = false;
1210 		} else if (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2) {
1211 			if (ath_is_alt_ant_ratio_better(alt_ratio,
1212 						ATH_ANT_DIV_COMB_LNA1_DELTA_MID,
1213 						ATH_ANT_DIV_COMB_LNA1_DELTA_LOW,
1214 						main_rssi_avg, alt_rssi_avg,
1215 						antcomb->total_pkt_count))
1216 				antcomb->second_ratio = true;
1217 			else
1218 				antcomb->second_ratio = false;
1219 		} else {
1220 			if ((((alt_ratio >= ATH_ANT_DIV_COMB_ALT_ANT_RATIO2) &&
1221 			    (alt_rssi_avg > main_rssi_avg +
1222 			    ATH_ANT_DIV_COMB_LNA1_DELTA_HI)) ||
1223 			    (alt_rssi_avg > main_rssi_avg)) &&
1224 			    (antcomb->total_pkt_count > 50))
1225 				antcomb->second_ratio = true;
1226 			else
1227 				antcomb->second_ratio = false;
1228 		}
1229 
1230 		/* set alt to the conf with maximun ratio */
1231 		if (antcomb->first_ratio && antcomb->second_ratio) {
1232 			if (antcomb->rssi_second > antcomb->rssi_third) {
1233 				/* first alt*/
1234 				if ((antcomb->first_quick_scan_conf ==
1235 				    ATH_ANT_DIV_COMB_LNA1) ||
1236 				    (antcomb->first_quick_scan_conf ==
1237 				    ATH_ANT_DIV_COMB_LNA2))
1238 					/* Set alt LNA1 or LNA2*/
1239 					if (div_ant_conf->main_lna_conf ==
1240 					    ATH_ANT_DIV_COMB_LNA2)
1241 						div_ant_conf->alt_lna_conf =
1242 							ATH_ANT_DIV_COMB_LNA1;
1243 					else
1244 						div_ant_conf->alt_lna_conf =
1245 							ATH_ANT_DIV_COMB_LNA2;
1246 				else
1247 					/* Set alt to A+B or A-B */
1248 					div_ant_conf->alt_lna_conf =
1249 						antcomb->first_quick_scan_conf;
1250 			} else if ((antcomb->second_quick_scan_conf ==
1251 				   ATH_ANT_DIV_COMB_LNA1) ||
1252 				   (antcomb->second_quick_scan_conf ==
1253 				   ATH_ANT_DIV_COMB_LNA2)) {
1254 				/* Set alt LNA1 or LNA2 */
1255 				if (div_ant_conf->main_lna_conf ==
1256 				    ATH_ANT_DIV_COMB_LNA2)
1257 					div_ant_conf->alt_lna_conf =
1258 						ATH_ANT_DIV_COMB_LNA1;
1259 				else
1260 					div_ant_conf->alt_lna_conf =
1261 						ATH_ANT_DIV_COMB_LNA2;
1262 			} else {
1263 				/* Set alt to A+B or A-B */
1264 				div_ant_conf->alt_lna_conf =
1265 					antcomb->second_quick_scan_conf;
1266 			}
1267 		} else if (antcomb->first_ratio) {
1268 			/* first alt */
1269 			if ((antcomb->first_quick_scan_conf ==
1270 			    ATH_ANT_DIV_COMB_LNA1) ||
1271 			    (antcomb->first_quick_scan_conf ==
1272 			    ATH_ANT_DIV_COMB_LNA2))
1273 					/* Set alt LNA1 or LNA2 */
1274 				if (div_ant_conf->main_lna_conf ==
1275 				    ATH_ANT_DIV_COMB_LNA2)
1276 					div_ant_conf->alt_lna_conf =
1277 							ATH_ANT_DIV_COMB_LNA1;
1278 				else
1279 					div_ant_conf->alt_lna_conf =
1280 							ATH_ANT_DIV_COMB_LNA2;
1281 			else
1282 				/* Set alt to A+B or A-B */
1283 				div_ant_conf->alt_lna_conf =
1284 						antcomb->first_quick_scan_conf;
1285 		} else if (antcomb->second_ratio) {
1286 				/* second alt */
1287 			if ((antcomb->second_quick_scan_conf ==
1288 			    ATH_ANT_DIV_COMB_LNA1) ||
1289 			    (antcomb->second_quick_scan_conf ==
1290 			    ATH_ANT_DIV_COMB_LNA2))
1291 				/* Set alt LNA1 or LNA2 */
1292 				if (div_ant_conf->main_lna_conf ==
1293 				    ATH_ANT_DIV_COMB_LNA2)
1294 					div_ant_conf->alt_lna_conf =
1295 						ATH_ANT_DIV_COMB_LNA1;
1296 				else
1297 					div_ant_conf->alt_lna_conf =
1298 						ATH_ANT_DIV_COMB_LNA2;
1299 			else
1300 				/* Set alt to A+B or A-B */
1301 				div_ant_conf->alt_lna_conf =
1302 						antcomb->second_quick_scan_conf;
1303 		} else {
1304 			/* main is largest */
1305 			if ((antcomb->main_conf == ATH_ANT_DIV_COMB_LNA1) ||
1306 			    (antcomb->main_conf == ATH_ANT_DIV_COMB_LNA2))
1307 				/* Set alt LNA1 or LNA2 */
1308 				if (div_ant_conf->main_lna_conf ==
1309 				    ATH_ANT_DIV_COMB_LNA2)
1310 					div_ant_conf->alt_lna_conf =
1311 							ATH_ANT_DIV_COMB_LNA1;
1312 				else
1313 					div_ant_conf->alt_lna_conf =
1314 							ATH_ANT_DIV_COMB_LNA2;
1315 			else
1316 				/* Set alt to A+B or A-B */
1317 				div_ant_conf->alt_lna_conf = antcomb->main_conf;
1318 		}
1319 		break;
1320 	default:
1321 		break;
1322 	}
1323 }
1324 
1325 static void ath_ant_div_conf_fast_divbias(struct ath_hw_antcomb_conf *ant_conf,
1326 		struct ath_ant_comb *antcomb, int alt_ratio)
1327 {
1328 	if (ant_conf->div_group == 0) {
1329 		/* Adjust the fast_div_bias based on main and alt lna conf */
1330 		switch ((ant_conf->main_lna_conf << 4) |
1331 				ant_conf->alt_lna_conf) {
1332 		case 0x01: /* A-B LNA2 */
1333 			ant_conf->fast_div_bias = 0x3b;
1334 			break;
1335 		case 0x02: /* A-B LNA1 */
1336 			ant_conf->fast_div_bias = 0x3d;
1337 			break;
1338 		case 0x03: /* A-B A+B */
1339 			ant_conf->fast_div_bias = 0x1;
1340 			break;
1341 		case 0x10: /* LNA2 A-B */
1342 			ant_conf->fast_div_bias = 0x7;
1343 			break;
1344 		case 0x12: /* LNA2 LNA1 */
1345 			ant_conf->fast_div_bias = 0x2;
1346 			break;
1347 		case 0x13: /* LNA2 A+B */
1348 			ant_conf->fast_div_bias = 0x7;
1349 			break;
1350 		case 0x20: /* LNA1 A-B */
1351 			ant_conf->fast_div_bias = 0x6;
1352 			break;
1353 		case 0x21: /* LNA1 LNA2 */
1354 			ant_conf->fast_div_bias = 0x0;
1355 			break;
1356 		case 0x23: /* LNA1 A+B */
1357 			ant_conf->fast_div_bias = 0x6;
1358 			break;
1359 		case 0x30: /* A+B A-B */
1360 			ant_conf->fast_div_bias = 0x1;
1361 			break;
1362 		case 0x31: /* A+B LNA2 */
1363 			ant_conf->fast_div_bias = 0x3b;
1364 			break;
1365 		case 0x32: /* A+B LNA1 */
1366 			ant_conf->fast_div_bias = 0x3d;
1367 			break;
1368 		default:
1369 			break;
1370 		}
1371 	} else if (ant_conf->div_group == 1) {
1372 		/* Adjust the fast_div_bias based on main and alt_lna_conf */
1373 		switch ((ant_conf->main_lna_conf << 4) |
1374 			ant_conf->alt_lna_conf) {
1375 		case 0x01: /* A-B LNA2 */
1376 			ant_conf->fast_div_bias = 0x1;
1377 			ant_conf->main_gaintb = 0;
1378 			ant_conf->alt_gaintb = 0;
1379 			break;
1380 		case 0x02: /* A-B LNA1 */
1381 			ant_conf->fast_div_bias = 0x1;
1382 			ant_conf->main_gaintb = 0;
1383 			ant_conf->alt_gaintb = 0;
1384 			break;
1385 		case 0x03: /* A-B A+B */
1386 			ant_conf->fast_div_bias = 0x1;
1387 			ant_conf->main_gaintb = 0;
1388 			ant_conf->alt_gaintb = 0;
1389 			break;
1390 		case 0x10: /* LNA2 A-B */
1391 			if (!(antcomb->scan) &&
1392 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1393 				ant_conf->fast_div_bias = 0x3f;
1394 			else
1395 				ant_conf->fast_div_bias = 0x1;
1396 			ant_conf->main_gaintb = 0;
1397 			ant_conf->alt_gaintb = 0;
1398 			break;
1399 		case 0x12: /* LNA2 LNA1 */
1400 			ant_conf->fast_div_bias = 0x1;
1401 			ant_conf->main_gaintb = 0;
1402 			ant_conf->alt_gaintb = 0;
1403 			break;
1404 		case 0x13: /* LNA2 A+B */
1405 			if (!(antcomb->scan) &&
1406 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1407 				ant_conf->fast_div_bias = 0x3f;
1408 			else
1409 				ant_conf->fast_div_bias = 0x1;
1410 			ant_conf->main_gaintb = 0;
1411 			ant_conf->alt_gaintb = 0;
1412 			break;
1413 		case 0x20: /* LNA1 A-B */
1414 			if (!(antcomb->scan) &&
1415 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1416 				ant_conf->fast_div_bias = 0x3f;
1417 			else
1418 				ant_conf->fast_div_bias = 0x1;
1419 			ant_conf->main_gaintb = 0;
1420 			ant_conf->alt_gaintb = 0;
1421 			break;
1422 		case 0x21: /* LNA1 LNA2 */
1423 			ant_conf->fast_div_bias = 0x1;
1424 			ant_conf->main_gaintb = 0;
1425 			ant_conf->alt_gaintb = 0;
1426 			break;
1427 		case 0x23: /* LNA1 A+B */
1428 			if (!(antcomb->scan) &&
1429 			    (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1430 				ant_conf->fast_div_bias = 0x3f;
1431 			else
1432 				ant_conf->fast_div_bias = 0x1;
1433 			ant_conf->main_gaintb = 0;
1434 			ant_conf->alt_gaintb = 0;
1435 			break;
1436 		case 0x30: /* A+B A-B */
1437 			ant_conf->fast_div_bias = 0x1;
1438 			ant_conf->main_gaintb = 0;
1439 			ant_conf->alt_gaintb = 0;
1440 			break;
1441 		case 0x31: /* A+B LNA2 */
1442 			ant_conf->fast_div_bias = 0x1;
1443 			ant_conf->main_gaintb = 0;
1444 			ant_conf->alt_gaintb = 0;
1445 			break;
1446 		case 0x32: /* A+B LNA1 */
1447 			ant_conf->fast_div_bias = 0x1;
1448 			ant_conf->main_gaintb = 0;
1449 			ant_conf->alt_gaintb = 0;
1450 			break;
1451 		default:
1452 			break;
1453 		}
1454 	} else if (ant_conf->div_group == 2) {
1455 		/* Adjust the fast_div_bias based on main and alt_lna_conf */
1456 		switch ((ant_conf->main_lna_conf << 4) |
1457 				ant_conf->alt_lna_conf) {
1458 		case 0x01: /* A-B LNA2 */
1459 			ant_conf->fast_div_bias = 0x1;
1460 			ant_conf->main_gaintb = 0;
1461 			ant_conf->alt_gaintb = 0;
1462 			break;
1463 		case 0x02: /* A-B LNA1 */
1464 			ant_conf->fast_div_bias = 0x1;
1465 			ant_conf->main_gaintb = 0;
1466 			ant_conf->alt_gaintb = 0;
1467 			break;
1468 		case 0x03: /* A-B A+B */
1469 			ant_conf->fast_div_bias = 0x1;
1470 			ant_conf->main_gaintb = 0;
1471 			ant_conf->alt_gaintb = 0;
1472 			break;
1473 		case 0x10: /* LNA2 A-B */
1474 			if (!(antcomb->scan) &&
1475 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1476 				ant_conf->fast_div_bias = 0x1;
1477 			else
1478 				ant_conf->fast_div_bias = 0x2;
1479 			ant_conf->main_gaintb = 0;
1480 			ant_conf->alt_gaintb = 0;
1481 			break;
1482 		case 0x12: /* LNA2 LNA1 */
1483 			ant_conf->fast_div_bias = 0x1;
1484 			ant_conf->main_gaintb = 0;
1485 			ant_conf->alt_gaintb = 0;
1486 			break;
1487 		case 0x13: /* LNA2 A+B */
1488 			if (!(antcomb->scan) &&
1489 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1490 				ant_conf->fast_div_bias = 0x1;
1491 			else
1492 				ant_conf->fast_div_bias = 0x2;
1493 			ant_conf->main_gaintb = 0;
1494 			ant_conf->alt_gaintb = 0;
1495 			break;
1496 		case 0x20: /* LNA1 A-B */
1497 			if (!(antcomb->scan) &&
1498 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1499 				ant_conf->fast_div_bias = 0x1;
1500 			else
1501 				ant_conf->fast_div_bias = 0x2;
1502 			ant_conf->main_gaintb = 0;
1503 			ant_conf->alt_gaintb = 0;
1504 			break;
1505 		case 0x21: /* LNA1 LNA2 */
1506 			ant_conf->fast_div_bias = 0x1;
1507 			ant_conf->main_gaintb = 0;
1508 			ant_conf->alt_gaintb = 0;
1509 			break;
1510 		case 0x23: /* LNA1 A+B */
1511 			if (!(antcomb->scan) &&
1512 				(alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO))
1513 				ant_conf->fast_div_bias = 0x1;
1514 			else
1515 				ant_conf->fast_div_bias = 0x2;
1516 			ant_conf->main_gaintb = 0;
1517 			ant_conf->alt_gaintb = 0;
1518 			break;
1519 		case 0x30: /* A+B A-B */
1520 			ant_conf->fast_div_bias = 0x1;
1521 			ant_conf->main_gaintb = 0;
1522 			ant_conf->alt_gaintb = 0;
1523 			break;
1524 		case 0x31: /* A+B LNA2 */
1525 			ant_conf->fast_div_bias = 0x1;
1526 			ant_conf->main_gaintb = 0;
1527 			ant_conf->alt_gaintb = 0;
1528 			break;
1529 		case 0x32: /* A+B LNA1 */
1530 			ant_conf->fast_div_bias = 0x1;
1531 			ant_conf->main_gaintb = 0;
1532 			ant_conf->alt_gaintb = 0;
1533 			break;
1534 		default:
1535 			break;
1536 		}
1537 	}
1538 }
1539 
1540 /* Antenna diversity and combining */
1541 static void ath_ant_comb_scan(struct ath_softc *sc, struct ath_rx_status *rs)
1542 {
1543 	struct ath_hw_antcomb_conf div_ant_conf;
1544 	struct ath_ant_comb *antcomb = &sc->ant_comb;
1545 	int alt_ratio = 0, alt_rssi_avg = 0, main_rssi_avg = 0, curr_alt_set;
1546 	int curr_main_set;
1547 	int main_rssi = rs->rs_rssi_ctl0;
1548 	int alt_rssi = rs->rs_rssi_ctl1;
1549 	int rx_ant_conf,  main_ant_conf;
1550 	bool short_scan = false;
1551 
1552 	rx_ant_conf = (rs->rs_rssi_ctl2 >> ATH_ANT_RX_CURRENT_SHIFT) &
1553 		       ATH_ANT_RX_MASK;
1554 	main_ant_conf = (rs->rs_rssi_ctl2 >> ATH_ANT_RX_MAIN_SHIFT) &
1555 			 ATH_ANT_RX_MASK;
1556 
1557 	/* Record packet only when both main_rssi and  alt_rssi is positive */
1558 	if (main_rssi > 0 && alt_rssi > 0) {
1559 		antcomb->total_pkt_count++;
1560 		antcomb->main_total_rssi += main_rssi;
1561 		antcomb->alt_total_rssi  += alt_rssi;
1562 		if (main_ant_conf == rx_ant_conf)
1563 			antcomb->main_recv_cnt++;
1564 		else
1565 			antcomb->alt_recv_cnt++;
1566 	}
1567 
1568 	/* Short scan check */
1569 	if (antcomb->scan && antcomb->alt_good) {
1570 		if (time_after(jiffies, antcomb->scan_start_time +
1571 		    msecs_to_jiffies(ATH_ANT_DIV_COMB_SHORT_SCAN_INTR)))
1572 			short_scan = true;
1573 		else
1574 			if (antcomb->total_pkt_count ==
1575 			    ATH_ANT_DIV_COMB_SHORT_SCAN_PKTCOUNT) {
1576 				alt_ratio = ((antcomb->alt_recv_cnt * 100) /
1577 					    antcomb->total_pkt_count);
1578 				if (alt_ratio < ATH_ANT_DIV_COMB_ALT_ANT_RATIO)
1579 					short_scan = true;
1580 			}
1581 	}
1582 
1583 	if (((antcomb->total_pkt_count < ATH_ANT_DIV_COMB_MAX_PKTCOUNT) ||
1584 	    rs->rs_moreaggr) && !short_scan)
1585 		return;
1586 
1587 	if (antcomb->total_pkt_count) {
1588 		alt_ratio = ((antcomb->alt_recv_cnt * 100) /
1589 			     antcomb->total_pkt_count);
1590 		main_rssi_avg = (antcomb->main_total_rssi /
1591 				 antcomb->total_pkt_count);
1592 		alt_rssi_avg = (antcomb->alt_total_rssi /
1593 				 antcomb->total_pkt_count);
1594 	}
1595 
1596 
1597 	ath9k_hw_antdiv_comb_conf_get(sc->sc_ah, &div_ant_conf);
1598 	curr_alt_set = div_ant_conf.alt_lna_conf;
1599 	curr_main_set = div_ant_conf.main_lna_conf;
1600 
1601 	antcomb->count++;
1602 
1603 	if (antcomb->count == ATH_ANT_DIV_COMB_MAX_COUNT) {
1604 		if (alt_ratio > ATH_ANT_DIV_COMB_ALT_ANT_RATIO) {
1605 			ath_lnaconf_alt_good_scan(antcomb, div_ant_conf,
1606 						  main_rssi_avg);
1607 			antcomb->alt_good = true;
1608 		} else {
1609 			antcomb->alt_good = false;
1610 		}
1611 
1612 		antcomb->count = 0;
1613 		antcomb->scan = true;
1614 		antcomb->scan_not_start = true;
1615 	}
1616 
1617 	if (!antcomb->scan) {
1618 		if (ath_ant_div_comb_alt_check(div_ant_conf.div_group,
1619 					alt_ratio, curr_main_set, curr_alt_set,
1620 					alt_rssi_avg, main_rssi_avg)) {
1621 			if (curr_alt_set == ATH_ANT_DIV_COMB_LNA2) {
1622 				/* Switch main and alt LNA */
1623 				div_ant_conf.main_lna_conf =
1624 						ATH_ANT_DIV_COMB_LNA2;
1625 				div_ant_conf.alt_lna_conf  =
1626 						ATH_ANT_DIV_COMB_LNA1;
1627 			} else if (curr_alt_set == ATH_ANT_DIV_COMB_LNA1) {
1628 				div_ant_conf.main_lna_conf =
1629 						ATH_ANT_DIV_COMB_LNA1;
1630 				div_ant_conf.alt_lna_conf  =
1631 						ATH_ANT_DIV_COMB_LNA2;
1632 			}
1633 
1634 			goto div_comb_done;
1635 		} else if ((curr_alt_set != ATH_ANT_DIV_COMB_LNA1) &&
1636 			   (curr_alt_set != ATH_ANT_DIV_COMB_LNA2)) {
1637 			/* Set alt to another LNA */
1638 			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2)
1639 				div_ant_conf.alt_lna_conf =
1640 						ATH_ANT_DIV_COMB_LNA1;
1641 			else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1)
1642 				div_ant_conf.alt_lna_conf =
1643 						ATH_ANT_DIV_COMB_LNA2;
1644 
1645 			goto div_comb_done;
1646 		}
1647 
1648 		if ((alt_rssi_avg < (main_rssi_avg +
1649 						div_ant_conf.lna1_lna2_delta)))
1650 			goto div_comb_done;
1651 	}
1652 
1653 	if (!antcomb->scan_not_start) {
1654 		switch (curr_alt_set) {
1655 		case ATH_ANT_DIV_COMB_LNA2:
1656 			antcomb->rssi_lna2 = alt_rssi_avg;
1657 			antcomb->rssi_lna1 = main_rssi_avg;
1658 			antcomb->scan = true;
1659 			/* set to A+B */
1660 			div_ant_conf.main_lna_conf =
1661 				ATH_ANT_DIV_COMB_LNA1;
1662 			div_ant_conf.alt_lna_conf  =
1663 				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1664 			break;
1665 		case ATH_ANT_DIV_COMB_LNA1:
1666 			antcomb->rssi_lna1 = alt_rssi_avg;
1667 			antcomb->rssi_lna2 = main_rssi_avg;
1668 			antcomb->scan = true;
1669 			/* set to A+B */
1670 			div_ant_conf.main_lna_conf = ATH_ANT_DIV_COMB_LNA2;
1671 			div_ant_conf.alt_lna_conf  =
1672 				ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1673 			break;
1674 		case ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2:
1675 			antcomb->rssi_add = alt_rssi_avg;
1676 			antcomb->scan = true;
1677 			/* set to A-B */
1678 			div_ant_conf.alt_lna_conf =
1679 				ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1680 			break;
1681 		case ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2:
1682 			antcomb->rssi_sub = alt_rssi_avg;
1683 			antcomb->scan = false;
1684 			if (antcomb->rssi_lna2 >
1685 			    (antcomb->rssi_lna1 +
1686 			    ATH_ANT_DIV_COMB_LNA1_LNA2_SWITCH_DELTA)) {
1687 				/* use LNA2 as main LNA */
1688 				if ((antcomb->rssi_add > antcomb->rssi_lna1) &&
1689 				    (antcomb->rssi_add > antcomb->rssi_sub)) {
1690 					/* set to A+B */
1691 					div_ant_conf.main_lna_conf =
1692 						ATH_ANT_DIV_COMB_LNA2;
1693 					div_ant_conf.alt_lna_conf  =
1694 						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1695 				} else if (antcomb->rssi_sub >
1696 					   antcomb->rssi_lna1) {
1697 					/* set to A-B */
1698 					div_ant_conf.main_lna_conf =
1699 						ATH_ANT_DIV_COMB_LNA2;
1700 					div_ant_conf.alt_lna_conf =
1701 						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1702 				} else {
1703 					/* set to LNA1 */
1704 					div_ant_conf.main_lna_conf =
1705 						ATH_ANT_DIV_COMB_LNA2;
1706 					div_ant_conf.alt_lna_conf =
1707 						ATH_ANT_DIV_COMB_LNA1;
1708 				}
1709 			} else {
1710 				/* use LNA1 as main LNA */
1711 				if ((antcomb->rssi_add > antcomb->rssi_lna2) &&
1712 				    (antcomb->rssi_add > antcomb->rssi_sub)) {
1713 					/* set to A+B */
1714 					div_ant_conf.main_lna_conf =
1715 						ATH_ANT_DIV_COMB_LNA1;
1716 					div_ant_conf.alt_lna_conf  =
1717 						ATH_ANT_DIV_COMB_LNA1_PLUS_LNA2;
1718 				} else if (antcomb->rssi_sub >
1719 					   antcomb->rssi_lna1) {
1720 					/* set to A-B */
1721 					div_ant_conf.main_lna_conf =
1722 						ATH_ANT_DIV_COMB_LNA1;
1723 					div_ant_conf.alt_lna_conf =
1724 						ATH_ANT_DIV_COMB_LNA1_MINUS_LNA2;
1725 				} else {
1726 					/* set to LNA2 */
1727 					div_ant_conf.main_lna_conf =
1728 						ATH_ANT_DIV_COMB_LNA1;
1729 					div_ant_conf.alt_lna_conf =
1730 						ATH_ANT_DIV_COMB_LNA2;
1731 				}
1732 			}
1733 			break;
1734 		default:
1735 			break;
1736 		}
1737 	} else {
1738 		if (!antcomb->alt_good) {
1739 			antcomb->scan_not_start = false;
1740 			/* Set alt to another LNA */
1741 			if (curr_main_set == ATH_ANT_DIV_COMB_LNA2) {
1742 				div_ant_conf.main_lna_conf =
1743 						ATH_ANT_DIV_COMB_LNA2;
1744 				div_ant_conf.alt_lna_conf =
1745 						ATH_ANT_DIV_COMB_LNA1;
1746 			} else if (curr_main_set == ATH_ANT_DIV_COMB_LNA1) {
1747 				div_ant_conf.main_lna_conf =
1748 						ATH_ANT_DIV_COMB_LNA1;
1749 				div_ant_conf.alt_lna_conf =
1750 						ATH_ANT_DIV_COMB_LNA2;
1751 			}
1752 			goto div_comb_done;
1753 		}
1754 	}
1755 
1756 	ath_select_ant_div_from_quick_scan(antcomb, &div_ant_conf,
1757 					   main_rssi_avg, alt_rssi_avg,
1758 					   alt_ratio);
1759 
1760 	antcomb->quick_scan_cnt++;
1761 
1762 div_comb_done:
1763 	ath_ant_div_conf_fast_divbias(&div_ant_conf, antcomb, alt_ratio);
1764 	ath9k_hw_antdiv_comb_conf_set(sc->sc_ah, &div_ant_conf);
1765 
1766 	antcomb->scan_start_time = jiffies;
1767 	antcomb->total_pkt_count = 0;
1768 	antcomb->main_total_rssi = 0;
1769 	antcomb->alt_total_rssi = 0;
1770 	antcomb->main_recv_cnt = 0;
1771 	antcomb->alt_recv_cnt = 0;
1772 }
1773 
1774 int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
1775 {
1776 	struct ath_buf *bf;
1777 	struct sk_buff *skb = NULL, *requeue_skb, *hdr_skb;
1778 	struct ieee80211_rx_status *rxs;
1779 	struct ath_hw *ah = sc->sc_ah;
1780 	struct ath_common *common = ath9k_hw_common(ah);
1781 	struct ieee80211_hw *hw = sc->hw;
1782 	struct ieee80211_hdr *hdr;
1783 	int retval;
1784 	bool decrypt_error = false;
1785 	struct ath_rx_status rs;
1786 	enum ath9k_rx_qtype qtype;
1787 	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
1788 	int dma_type;
1789 	u8 rx_status_len = ah->caps.rx_status_len;
1790 	u64 tsf = 0;
1791 	u32 tsf_lower = 0;
1792 	unsigned long flags;
1793 
1794 	if (edma)
1795 		dma_type = DMA_BIDIRECTIONAL;
1796 	else
1797 		dma_type = DMA_FROM_DEVICE;
1798 
1799 	qtype = hp ? ATH9K_RX_QUEUE_HP : ATH9K_RX_QUEUE_LP;
1800 	spin_lock_bh(&sc->rx.rxbuflock);
1801 
1802 	tsf = ath9k_hw_gettsf64(ah);
1803 	tsf_lower = tsf & 0xffffffff;
1804 
1805 	do {
1806 		/* If handling rx interrupt and flush is in progress => exit */
1807 		if ((sc->sc_flags & SC_OP_RXFLUSH) && (flush == 0))
1808 			break;
1809 
1810 		memset(&rs, 0, sizeof(rs));
1811 		if (edma)
1812 			bf = ath_edma_get_next_rx_buf(sc, &rs, qtype);
1813 		else
1814 			bf = ath_get_next_rx_buf(sc, &rs);
1815 
1816 		if (!bf)
1817 			break;
1818 
1819 		skb = bf->bf_mpdu;
1820 		if (!skb)
1821 			continue;
1822 
1823 		/*
1824 		 * Take frame header from the first fragment and RX status from
1825 		 * the last one.
1826 		 */
1827 		if (sc->rx.frag)
1828 			hdr_skb = sc->rx.frag;
1829 		else
1830 			hdr_skb = skb;
1831 
1832 		hdr = (struct ieee80211_hdr *) (hdr_skb->data + rx_status_len);
1833 		rxs = IEEE80211_SKB_RXCB(hdr_skb);
1834 		if (ieee80211_is_beacon(hdr->frame_control)) {
1835 			RX_STAT_INC(rx_beacons);
1836 			if (!is_zero_ether_addr(common->curbssid) &&
1837 			    ether_addr_equal(hdr->addr3, common->curbssid))
1838 				rs.is_mybeacon = true;
1839 			else
1840 				rs.is_mybeacon = false;
1841 		}
1842 		else
1843 			rs.is_mybeacon = false;
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 (sc->sc_flags & SC_OP_RXFLUSH) {
1852 			RX_STAT_INC(rx_drop_rxflush);
1853 			goto requeue_drop_frag;
1854 		}
1855 
1856 		memset(rxs, 0, sizeof(struct ieee80211_rx_status));
1857 
1858 		rxs->mactime = (tsf & ~0xffffffffULL) | rs.rs_tstamp;
1859 		if (rs.rs_tstamp > tsf_lower &&
1860 		    unlikely(rs.rs_tstamp - tsf_lower > 0x10000000))
1861 			rxs->mactime -= 0x100000000ULL;
1862 
1863 		if (rs.rs_tstamp < tsf_lower &&
1864 		    unlikely(tsf_lower - rs.rs_tstamp > 0x10000000))
1865 			rxs->mactime += 0x100000000ULL;
1866 
1867 		retval = ath9k_rx_skb_preprocess(common, hw, hdr, &rs,
1868 						 rxs, &decrypt_error);
1869 		if (retval)
1870 			goto requeue_drop_frag;
1871 
1872 		if (rs.is_mybeacon) {
1873 			sc->hw_busy_count = 0;
1874 			ath_start_rx_poll(sc, 3);
1875 		}
1876 		/* Ensure we always have an skb to requeue once we are done
1877 		 * processing the current buffer's skb */
1878 		requeue_skb = ath_rxbuf_alloc(common, common->rx_bufsize, GFP_ATOMIC);
1879 
1880 		/* If there is no memory we ignore the current RX'd frame,
1881 		 * tell hardware it can give us a new frame using the old
1882 		 * skb and put it at the tail of the sc->rx.rxbuf list for
1883 		 * processing. */
1884 		if (!requeue_skb) {
1885 			RX_STAT_INC(rx_oom_err);
1886 			goto requeue_drop_frag;
1887 		}
1888 
1889 		/* Unmap the frame */
1890 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
1891 				 common->rx_bufsize,
1892 				 dma_type);
1893 
1894 		skb_put(skb, rs.rs_datalen + ah->caps.rx_status_len);
1895 		if (ah->caps.rx_status_len)
1896 			skb_pull(skb, ah->caps.rx_status_len);
1897 
1898 		if (!rs.rs_more)
1899 			ath9k_rx_skb_postprocess(common, hdr_skb, &rs,
1900 						 rxs, decrypt_error);
1901 
1902 		/* We will now give hardware our shiny new allocated skb */
1903 		bf->bf_mpdu = requeue_skb;
1904 		bf->bf_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
1905 						 common->rx_bufsize,
1906 						 dma_type);
1907 		if (unlikely(dma_mapping_error(sc->dev,
1908 			  bf->bf_buf_addr))) {
1909 			dev_kfree_skb_any(requeue_skb);
1910 			bf->bf_mpdu = NULL;
1911 			bf->bf_buf_addr = 0;
1912 			ath_err(common, "dma_mapping_error() on RX\n");
1913 			ieee80211_rx(hw, skb);
1914 			break;
1915 		}
1916 
1917 		if (rs.rs_more) {
1918 			RX_STAT_INC(rx_frags);
1919 			/*
1920 			 * rs_more indicates chained descriptors which can be
1921 			 * used to link buffers together for a sort of
1922 			 * scatter-gather operation.
1923 			 */
1924 			if (sc->rx.frag) {
1925 				/* too many fragments - cannot handle frame */
1926 				dev_kfree_skb_any(sc->rx.frag);
1927 				dev_kfree_skb_any(skb);
1928 				RX_STAT_INC(rx_too_many_frags_err);
1929 				skb = NULL;
1930 			}
1931 			sc->rx.frag = skb;
1932 			goto requeue;
1933 		}
1934 
1935 		if (sc->rx.frag) {
1936 			int space = skb->len - skb_tailroom(hdr_skb);
1937 
1938 			if (pskb_expand_head(hdr_skb, 0, space, GFP_ATOMIC) < 0) {
1939 				dev_kfree_skb(skb);
1940 				RX_STAT_INC(rx_oom_err);
1941 				goto requeue_drop_frag;
1942 			}
1943 
1944 			sc->rx.frag = NULL;
1945 
1946 			skb_copy_from_linear_data(skb, skb_put(hdr_skb, skb->len),
1947 						  skb->len);
1948 			dev_kfree_skb_any(skb);
1949 			skb = hdr_skb;
1950 		}
1951 
1952 
1953 		if (ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB) {
1954 
1955 			/*
1956 			 * change the default rx antenna if rx diversity
1957 			 * chooses the other antenna 3 times in a row.
1958 			 */
1959 			if (sc->rx.defant != rs.rs_antenna) {
1960 				if (++sc->rx.rxotherant >= 3)
1961 					ath_setdefantenna(sc, rs.rs_antenna);
1962 			} else {
1963 				sc->rx.rxotherant = 0;
1964 			}
1965 
1966 		}
1967 
1968 		if (rxs->flag & RX_FLAG_MMIC_STRIPPED)
1969 			skb_trim(skb, skb->len - 8);
1970 
1971 		spin_lock_irqsave(&sc->sc_pm_lock, flags);
1972 
1973 		if ((sc->ps_flags & (PS_WAIT_FOR_BEACON |
1974 				     PS_WAIT_FOR_CAB |
1975 				     PS_WAIT_FOR_PSPOLL_DATA)) ||
1976 		    ath9k_check_auto_sleep(sc))
1977 			ath_rx_ps(sc, skb, rs.is_mybeacon);
1978 		spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
1979 
1980 		if ((ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB) && sc->ant_rx == 3)
1981 			ath_ant_comb_scan(sc, &rs);
1982 
1983 		ieee80211_rx(hw, skb);
1984 
1985 requeue_drop_frag:
1986 		if (sc->rx.frag) {
1987 			dev_kfree_skb_any(sc->rx.frag);
1988 			sc->rx.frag = NULL;
1989 		}
1990 requeue:
1991 		if (edma) {
1992 			list_add_tail(&bf->list, &sc->rx.rxbuf);
1993 			ath_rx_edma_buf_link(sc, qtype);
1994 		} else {
1995 			list_move_tail(&bf->list, &sc->rx.rxbuf);
1996 			ath_rx_buf_link(sc, bf);
1997 			if (!flush)
1998 				ath9k_hw_rxena(ah);
1999 		}
2000 	} while (1);
2001 
2002 	spin_unlock_bh(&sc->rx.rxbuflock);
2003 
2004 	if (!(ah->imask & ATH9K_INT_RXEOL)) {
2005 		ah->imask |= (ATH9K_INT_RXEOL | ATH9K_INT_RXORN);
2006 		ath9k_hw_set_interrupts(ah);
2007 	}
2008 
2009 	return 0;
2010 }
2011