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 
20 #define FUDGE 2
21 
22 static void ath9k_reset_beacon_status(struct ath_softc *sc)
23 {
24 	sc->beacon.tx_processed = false;
25 	sc->beacon.tx_last = false;
26 }
27 
28 /*
29  *  This function will modify certain transmit queue properties depending on
30  *  the operating mode of the station (AP or AdHoc).  Parameters are AIFS
31  *  settings and channel width min/max
32 */
33 static void ath9k_beaconq_config(struct ath_softc *sc)
34 {
35 	struct ath_hw *ah = sc->sc_ah;
36 	struct ath_common *common = ath9k_hw_common(ah);
37 	struct ath9k_tx_queue_info qi, qi_be;
38 	struct ath_txq *txq;
39 
40 	ath9k_hw_get_txq_props(ah, sc->beacon.beaconq, &qi);
41 
42 	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP ||
43 	    sc->sc_ah->opmode == NL80211_IFTYPE_MESH_POINT) {
44 		/* Always burst out beacon and CAB traffic. */
45 		qi.tqi_aifs = 1;
46 		qi.tqi_cwmin = 0;
47 		qi.tqi_cwmax = 0;
48 	} else {
49 		/* Adhoc mode; important thing is to use 2x cwmin. */
50 		txq = sc->tx.txq_map[IEEE80211_AC_BE];
51 		ath9k_hw_get_txq_props(ah, txq->axq_qnum, &qi_be);
52 		qi.tqi_aifs = qi_be.tqi_aifs;
53 		if (ah->slottime == ATH9K_SLOT_TIME_20)
54 			qi.tqi_cwmin = 2*qi_be.tqi_cwmin;
55 		else
56 			qi.tqi_cwmin = 4*qi_be.tqi_cwmin;
57 		qi.tqi_cwmax = qi_be.tqi_cwmax;
58 	}
59 
60 	if (!ath9k_hw_set_txq_props(ah, sc->beacon.beaconq, &qi)) {
61 		ath_err(common, "Unable to update h/w beacon queue parameters\n");
62 	} else {
63 		ath9k_hw_resettxqueue(ah, sc->beacon.beaconq);
64 	}
65 }
66 
67 /*
68  *  Associates the beacon frame buffer with a transmit descriptor.  Will set
69  *  up rate codes, and channel flags. Beacons are always sent out at the
70  *  lowest rate, and are not retried.
71 */
72 static void ath9k_beacon_setup(struct ath_softc *sc, struct ieee80211_vif *vif,
73 			     struct ath_buf *bf, int rateidx)
74 {
75 	struct sk_buff *skb = bf->bf_mpdu;
76 	struct ath_hw *ah = sc->sc_ah;
77 	struct ath_common *common = ath9k_hw_common(ah);
78 	struct ath_tx_info info;
79 	struct ieee80211_supported_band *sband;
80 	u8 chainmask = ah->txchainmask;
81 	u8 i, rate = 0;
82 
83 	sband = &common->sbands[sc->cur_chandef.chan->band];
84 	rate = sband->bitrates[rateidx].hw_value;
85 	if (vif->bss_conf.use_short_preamble)
86 		rate |= sband->bitrates[rateidx].hw_value_short;
87 
88 	memset(&info, 0, sizeof(info));
89 	info.pkt_len = skb->len + FCS_LEN;
90 	info.type = ATH9K_PKT_TYPE_BEACON;
91 	for (i = 0; i < 4; i++)
92 		info.txpower[i] = MAX_RATE_POWER;
93 	info.keyix = ATH9K_TXKEYIX_INVALID;
94 	info.keytype = ATH9K_KEY_TYPE_CLEAR;
95 	info.flags = ATH9K_TXDESC_NOACK | ATH9K_TXDESC_CLRDMASK;
96 
97 	info.buf_addr[0] = bf->bf_buf_addr;
98 	info.buf_len[0] = roundup(skb->len, 4);
99 
100 	info.is_first = true;
101 	info.is_last = true;
102 
103 	info.qcu = sc->beacon.beaconq;
104 
105 	info.rates[0].Tries = 1;
106 	info.rates[0].Rate = rate;
107 	info.rates[0].ChSel = ath_txchainmask_reduction(sc, chainmask, rate);
108 
109 	ath9k_hw_set_txdesc(ah, bf->bf_desc, &info);
110 }
111 
112 static struct ath_buf *ath9k_beacon_generate(struct ieee80211_hw *hw,
113 					     struct ieee80211_vif *vif)
114 {
115 	struct ath_softc *sc = hw->priv;
116 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
117 	struct ath_buf *bf;
118 	struct ath_vif *avp = (void *)vif->drv_priv;
119 	struct sk_buff *skb;
120 	struct ath_txq *cabq = sc->beacon.cabq;
121 	struct ieee80211_tx_info *info;
122 	struct ieee80211_mgmt *mgmt_hdr;
123 	int cabq_depth;
124 
125 	if (avp->av_bcbuf == NULL)
126 		return NULL;
127 
128 	bf = avp->av_bcbuf;
129 	skb = bf->bf_mpdu;
130 	if (skb) {
131 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
132 				 skb->len, DMA_TO_DEVICE);
133 		dev_kfree_skb_any(skb);
134 		bf->bf_buf_addr = 0;
135 		bf->bf_mpdu = NULL;
136 	}
137 
138 	skb = ieee80211_beacon_get(hw, vif);
139 	if (skb == NULL)
140 		return NULL;
141 
142 	bf->bf_mpdu = skb;
143 
144 	mgmt_hdr = (struct ieee80211_mgmt *)skb->data;
145 	mgmt_hdr->u.beacon.timestamp = avp->tsf_adjust;
146 
147 	info = IEEE80211_SKB_CB(skb);
148 
149 	ath_assign_seq(common, skb);
150 
151 	if (vif->p2p)
152 		ath9k_beacon_add_noa(sc, avp, skb);
153 
154 	bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
155 					 skb->len, DMA_TO_DEVICE);
156 	if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
157 		dev_kfree_skb_any(skb);
158 		bf->bf_mpdu = NULL;
159 		bf->bf_buf_addr = 0;
160 		ath_err(common, "dma_mapping_error on beaconing\n");
161 		return NULL;
162 	}
163 
164 	skb = ieee80211_get_buffered_bc(hw, vif);
165 
166 	/*
167 	 * if the CABQ traffic from previous DTIM is pending and the current
168 	 *  beacon is also a DTIM.
169 	 *  1) if there is only one vif let the cab traffic continue.
170 	 *  2) if there are more than one vif and we are using staggered
171 	 *     beacons, then drain the cabq by dropping all the frames in
172 	 *     the cabq so that the current vifs cab traffic can be scheduled.
173 	 */
174 	spin_lock_bh(&cabq->axq_lock);
175 	cabq_depth = cabq->axq_depth;
176 	spin_unlock_bh(&cabq->axq_lock);
177 
178 	if (skb && cabq_depth) {
179 		if (sc->cur_chan->nvifs > 1) {
180 			ath_dbg(common, BEACON,
181 				"Flushing previous cabq traffic\n");
182 			ath_draintxq(sc, cabq);
183 		}
184 	}
185 
186 	ath9k_beacon_setup(sc, vif, bf, info->control.rates[0].idx);
187 
188 	if (skb)
189 		ath_tx_cabq(hw, vif, skb);
190 
191 	return bf;
192 }
193 
194 void ath9k_beacon_assign_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
195 {
196 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
197 	struct ath_vif *avp = (void *)vif->drv_priv;
198 	int slot;
199 
200 	avp->av_bcbuf = list_first_entry(&sc->beacon.bbuf, struct ath_buf, list);
201 	list_del(&avp->av_bcbuf->list);
202 
203 	for (slot = 0; slot < ATH_BCBUF; slot++) {
204 		if (sc->beacon.bslot[slot] == NULL) {
205 			avp->av_bslot = slot;
206 			break;
207 		}
208 	}
209 
210 	sc->beacon.bslot[avp->av_bslot] = vif;
211 	sc->nbcnvifs++;
212 
213 	ath_dbg(common, CONFIG, "Added interface at beacon slot: %d\n",
214 		avp->av_bslot);
215 }
216 
217 void ath9k_beacon_remove_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
218 {
219 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
220 	struct ath_vif *avp = (void *)vif->drv_priv;
221 	struct ath_buf *bf = avp->av_bcbuf;
222 
223 	ath_dbg(common, CONFIG, "Removing interface at beacon slot: %d\n",
224 		avp->av_bslot);
225 
226 	tasklet_disable(&sc->bcon_tasklet);
227 
228 	if (bf && bf->bf_mpdu) {
229 		struct sk_buff *skb = bf->bf_mpdu;
230 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
231 				 skb->len, DMA_TO_DEVICE);
232 		dev_kfree_skb_any(skb);
233 		bf->bf_mpdu = NULL;
234 		bf->bf_buf_addr = 0;
235 	}
236 
237 	avp->av_bcbuf = NULL;
238 	sc->beacon.bslot[avp->av_bslot] = NULL;
239 	sc->nbcnvifs--;
240 	list_add_tail(&bf->list, &sc->beacon.bbuf);
241 
242 	tasklet_enable(&sc->bcon_tasklet);
243 }
244 
245 static int ath9k_beacon_choose_slot(struct ath_softc *sc)
246 {
247 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
248 	struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;
249 	u16 intval;
250 	u32 tsftu;
251 	u64 tsf;
252 	int slot;
253 
254 	if (sc->sc_ah->opmode != NL80211_IFTYPE_AP &&
255 	    sc->sc_ah->opmode != NL80211_IFTYPE_MESH_POINT) {
256 		ath_dbg(common, BEACON, "slot 0, tsf: %llu\n",
257 			ath9k_hw_gettsf64(sc->sc_ah));
258 		return 0;
259 	}
260 
261 	intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
262 	tsf = ath9k_hw_gettsf64(sc->sc_ah);
263 	tsf += TU_TO_USEC(sc->sc_ah->config.sw_beacon_response_time);
264 	tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
265 	slot = (tsftu % (intval * ATH_BCBUF)) / intval;
266 
267 	ath_dbg(common, BEACON, "slot: %d tsf: %llu tsftu: %u\n",
268 		slot, tsf, tsftu / ATH_BCBUF);
269 
270 	return slot;
271 }
272 
273 static void ath9k_set_tsfadjust(struct ath_softc *sc, struct ieee80211_vif *vif)
274 {
275 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
276 	struct ath_vif *avp = (void *)vif->drv_priv;
277 	struct ath_beacon_config *cur_conf = &avp->chanctx->beacon;
278 	u32 tsfadjust;
279 
280 	if (avp->av_bslot == 0)
281 		return;
282 
283 	tsfadjust = cur_conf->beacon_interval * avp->av_bslot;
284 	tsfadjust = TU_TO_USEC(tsfadjust) / ATH_BCBUF;
285 	avp->tsf_adjust = cpu_to_le64(tsfadjust);
286 
287 	ath_dbg(common, CONFIG, "tsfadjust is: %llu for bslot: %d\n",
288 		(unsigned long long)tsfadjust, avp->av_bslot);
289 }
290 
291 bool ath9k_csa_is_finished(struct ath_softc *sc, struct ieee80211_vif *vif)
292 {
293 	if (!vif || !vif->csa_active)
294 		return false;
295 
296 	if (!ieee80211_csa_is_complete(vif))
297 		return false;
298 
299 	ieee80211_csa_finish(vif);
300 	return true;
301 }
302 
303 static void ath9k_csa_update_vif(void *data, u8 *mac, struct ieee80211_vif *vif)
304 {
305 	struct ath_softc *sc = data;
306 	ath9k_csa_is_finished(sc, vif);
307 }
308 
309 void ath9k_csa_update(struct ath_softc *sc)
310 {
311 	ieee80211_iterate_active_interfaces_atomic(sc->hw,
312 						   IEEE80211_IFACE_ITER_NORMAL,
313 						   ath9k_csa_update_vif, sc);
314 }
315 
316 void ath9k_beacon_tasklet(unsigned long data)
317 {
318 	struct ath_softc *sc = (struct ath_softc *)data;
319 	struct ath_hw *ah = sc->sc_ah;
320 	struct ath_common *common = ath9k_hw_common(ah);
321 	struct ath_buf *bf = NULL;
322 	struct ieee80211_vif *vif;
323 	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
324 	int slot;
325 
326 	if (test_bit(ATH_OP_HW_RESET, &common->op_flags)) {
327 		ath_dbg(common, RESET,
328 			"reset work is pending, skip beaconing now\n");
329 		return;
330 	}
331 
332 	/*
333 	 * Check if the previous beacon has gone out.  If
334 	 * not don't try to post another, skip this period
335 	 * and wait for the next.  Missed beacons indicate
336 	 * a problem and should not occur.  If we miss too
337 	 * many consecutive beacons reset the device.
338 	 */
339 	if (ath9k_hw_numtxpending(ah, sc->beacon.beaconq) != 0) {
340 		sc->beacon.bmisscnt++;
341 
342 		ath9k_hw_check_nav(ah);
343 
344 		/*
345 		 * If the previous beacon has not been transmitted
346 		 * and a MAC/BB hang has been identified, return
347 		 * here because a chip reset would have been
348 		 * initiated.
349 		 */
350 		if (!ath_hw_check(sc))
351 			return;
352 
353 		if (sc->beacon.bmisscnt < BSTUCK_THRESH * sc->nbcnvifs) {
354 			ath_dbg(common, BSTUCK,
355 				"missed %u consecutive beacons\n",
356 				sc->beacon.bmisscnt);
357 			ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
358 			if (sc->beacon.bmisscnt > 3)
359 				ath9k_hw_bstuck_nfcal(ah);
360 		} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
361 			ath_dbg(common, BSTUCK, "beacon is officially stuck\n");
362 			sc->beacon.bmisscnt = 0;
363 			ath9k_queue_reset(sc, RESET_TYPE_BEACON_STUCK);
364 		}
365 
366 		return;
367 	}
368 
369 	slot = ath9k_beacon_choose_slot(sc);
370 	vif = sc->beacon.bslot[slot];
371 
372 	/* EDMA devices check that in the tx completion function. */
373 	if (!edma) {
374 		if (ath9k_is_chanctx_enabled()) {
375 			ath_chanctx_beacon_sent_ev(sc,
376 					  ATH_CHANCTX_EVENT_BEACON_SENT);
377 		}
378 
379 		if (ath9k_csa_is_finished(sc, vif))
380 			return;
381 	}
382 
383 	if (!vif || !vif->bss_conf.enable_beacon)
384 		return;
385 
386 	if (ath9k_is_chanctx_enabled()) {
387 		ath_chanctx_event(sc, vif, ATH_CHANCTX_EVENT_BEACON_PREPARE);
388 	}
389 
390 	bf = ath9k_beacon_generate(sc->hw, vif);
391 
392 	if (sc->beacon.bmisscnt != 0) {
393 		ath_dbg(common, BSTUCK, "resume beacon xmit after %u misses\n",
394 			sc->beacon.bmisscnt);
395 		sc->beacon.bmisscnt = 0;
396 	}
397 
398 	/*
399 	 * Handle slot time change when a non-ERP station joins/leaves
400 	 * an 11g network.  The 802.11 layer notifies us via callback,
401 	 * we mark updateslot, then wait one beacon before effecting
402 	 * the change.  This gives associated stations at least one
403 	 * beacon interval to note the state change.
404 	 *
405 	 * NB: The slot time change state machine is clocked according
406 	 *     to whether we are bursting or staggering beacons.  We
407 	 *     recognize the request to update and record the current
408 	 *     slot then don't transition until that slot is reached
409 	 *     again.  If we miss a beacon for that slot then we'll be
410 	 *     slow to transition but we'll be sure at least one beacon
411 	 *     interval has passed.  When bursting slot is always left
412 	 *     set to ATH_BCBUF so this check is a noop.
413 	 */
414 	if (sc->beacon.updateslot == UPDATE) {
415 		sc->beacon.updateslot = COMMIT;
416 		sc->beacon.slotupdate = slot;
417 	} else if (sc->beacon.updateslot == COMMIT &&
418 		   sc->beacon.slotupdate == slot) {
419 		ah->slottime = sc->beacon.slottime;
420 		ath9k_hw_init_global_settings(ah);
421 		sc->beacon.updateslot = OK;
422 	}
423 
424 	if (bf) {
425 		ath9k_reset_beacon_status(sc);
426 
427 		ath_dbg(common, BEACON,
428 			"Transmitting beacon for slot: %d\n", slot);
429 
430 		/* NB: cabq traffic should already be queued and primed */
431 		ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bf->bf_daddr);
432 
433 		if (!edma)
434 			ath9k_hw_txstart(ah, sc->beacon.beaconq);
435 	}
436 }
437 
438 /*
439  * Both nexttbtt and intval have to be in usecs.
440  */
441 static void ath9k_beacon_init(struct ath_softc *sc, u32 nexttbtt,
442 			      u32 intval, bool reset_tsf)
443 {
444 	struct ath_hw *ah = sc->sc_ah;
445 
446 	ath9k_hw_disable_interrupts(ah);
447 	if (reset_tsf)
448 		ath9k_hw_reset_tsf(ah);
449 	ath9k_beaconq_config(sc);
450 	ath9k_hw_beaconinit(ah, nexttbtt, intval);
451 	sc->beacon.bmisscnt = 0;
452 	ath9k_hw_set_interrupts(ah);
453 	ath9k_hw_enable_interrupts(ah);
454 }
455 
456 /*
457  * For multi-bss ap support beacons are either staggered evenly over N slots or
458  * burst together.  For the former arrange for the SWBA to be delivered for each
459  * slot. Slots that are not occupied will generate nothing.
460  */
461 static void ath9k_beacon_config_ap(struct ath_softc *sc,
462 				   struct ath_beacon_config *conf)
463 {
464 	struct ath_hw *ah = sc->sc_ah;
465 
466 	ath9k_cmn_beacon_config_ap(ah, conf, ATH_BCBUF);
467 	ath9k_beacon_init(sc, conf->nexttbtt, conf->intval, false);
468 }
469 
470 static void ath9k_beacon_config_sta(struct ath_hw *ah,
471 				    struct ath_beacon_config *conf)
472 {
473 	struct ath9k_beacon_state bs;
474 
475 	if (ath9k_cmn_beacon_config_sta(ah, conf, &bs) == -EPERM)
476 		return;
477 
478 	ath9k_hw_disable_interrupts(ah);
479 	ath9k_hw_set_sta_beacon_timers(ah, &bs);
480 	ah->imask |= ATH9K_INT_BMISS;
481 
482 	ath9k_hw_set_interrupts(ah);
483 	ath9k_hw_enable_interrupts(ah);
484 }
485 
486 static void ath9k_beacon_config_adhoc(struct ath_softc *sc,
487 				      struct ath_beacon_config *conf)
488 {
489 	struct ath_hw *ah = sc->sc_ah;
490 	struct ath_common *common = ath9k_hw_common(ah);
491 
492 	ath9k_reset_beacon_status(sc);
493 
494 	ath9k_cmn_beacon_config_adhoc(ah, conf);
495 
496 	ath9k_beacon_init(sc, conf->nexttbtt, conf->intval, conf->ibss_creator);
497 
498 	/*
499 	 * Set the global 'beacon has been configured' flag for the
500 	 * joiner case in IBSS mode.
501 	 */
502 	if (!conf->ibss_creator && conf->enable_beacon)
503 		set_bit(ATH_OP_BEACONS, &common->op_flags);
504 }
505 
506 static bool ath9k_allow_beacon_config(struct ath_softc *sc,
507 				      struct ieee80211_vif *vif)
508 {
509 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
510 	struct ath_vif *avp = (void *)vif->drv_priv;
511 
512 	if (ath9k_is_chanctx_enabled()) {
513 		/*
514 		 * If the VIF is not present in the current channel context,
515 		 * then we can't do the usual opmode checks. Allow the
516 		 * beacon config for the VIF to be updated in this case and
517 		 * return immediately.
518 		 */
519 		if (sc->cur_chan != avp->chanctx)
520 			return true;
521 	}
522 
523 	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP) {
524 		if ((vif->type != NL80211_IFTYPE_AP) ||
525 		    (sc->nbcnvifs > 1)) {
526 			ath_dbg(common, CONFIG,
527 				"An AP interface is already present !\n");
528 			return false;
529 		}
530 	}
531 
532 	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
533 		if ((vif->type == NL80211_IFTYPE_STATION) &&
534 		    test_bit(ATH_OP_BEACONS, &common->op_flags) &&
535 		    vif != sc->cur_chan->primary_sta) {
536 			ath_dbg(common, CONFIG,
537 				"Beacon already configured for a station interface\n");
538 			return false;
539 		}
540 	}
541 
542 	return true;
543 }
544 
545 static void ath9k_cache_beacon_config(struct ath_softc *sc,
546 				      struct ath_chanctx *ctx,
547 				      struct ieee80211_bss_conf *bss_conf)
548 {
549 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
550 	struct ath_beacon_config *cur_conf = &ctx->beacon;
551 
552 	ath_dbg(common, BEACON,
553 		"Caching beacon data for BSS: %pM\n", bss_conf->bssid);
554 
555 	cur_conf->beacon_interval = bss_conf->beacon_int;
556 	cur_conf->dtim_period = bss_conf->dtim_period;
557 	cur_conf->dtim_count = 1;
558 	cur_conf->ibss_creator = bss_conf->ibss_creator;
559 
560 	/*
561 	 * It looks like mac80211 may end up using beacon interval of zero in
562 	 * some cases (at least for mesh point). Avoid getting into an
563 	 * infinite loop by using a bit safer value instead. To be safe,
564 	 * do sanity check on beacon interval for all operating modes.
565 	 */
566 	if (cur_conf->beacon_interval == 0)
567 		cur_conf->beacon_interval = 100;
568 
569 	cur_conf->bmiss_timeout =
570 		ATH_DEFAULT_BMISS_LIMIT * cur_conf->beacon_interval;
571 
572 	/*
573 	 * We don't parse dtim period from mac80211 during the driver
574 	 * initialization as it breaks association with hidden-ssid
575 	 * AP and it causes latency in roaming
576 	 */
577 	if (cur_conf->dtim_period == 0)
578 		cur_conf->dtim_period = 1;
579 
580 }
581 
582 void ath9k_beacon_config(struct ath_softc *sc, struct ieee80211_vif *vif,
583 			 u32 changed)
584 {
585 	struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
586         struct ath_hw *ah = sc->sc_ah;
587         struct ath_common *common = ath9k_hw_common(ah);
588 	struct ath_vif *avp = (void *)vif->drv_priv;
589 	struct ath_chanctx *ctx = avp->chanctx;
590 	struct ath_beacon_config *cur_conf;
591 	unsigned long flags;
592 	bool skip_beacon = false;
593 
594 	if (!ctx)
595 		return;
596 
597 	cur_conf = &avp->chanctx->beacon;
598 	if (vif->type == NL80211_IFTYPE_AP)
599 		ath9k_set_tsfadjust(sc, vif);
600 
601 	if (!ath9k_allow_beacon_config(sc, vif))
602 		return;
603 
604 	if (vif->type == NL80211_IFTYPE_STATION) {
605 		ath9k_cache_beacon_config(sc, ctx, bss_conf);
606 		if (ctx != sc->cur_chan)
607 			return;
608 
609 		ath9k_set_beacon(sc);
610 		set_bit(ATH_OP_BEACONS, &common->op_flags);
611 		return;
612 	}
613 
614 	/*
615 	 * Take care of multiple interfaces when
616 	 * enabling/disabling SWBA.
617 	 */
618 	if (changed & BSS_CHANGED_BEACON_ENABLED) {
619 		if (!bss_conf->enable_beacon &&
620 		    (sc->nbcnvifs <= 1)) {
621 			cur_conf->enable_beacon = false;
622 		} else if (bss_conf->enable_beacon) {
623 			cur_conf->enable_beacon = true;
624 			ath9k_cache_beacon_config(sc, ctx, bss_conf);
625 		}
626 	}
627 
628 	if (ctx != sc->cur_chan)
629 		return;
630 
631 	/*
632 	 * Configure the HW beacon registers only when we have a valid
633 	 * beacon interval.
634 	 */
635 	if (cur_conf->beacon_interval) {
636 		/*
637 		 * If we are joining an existing IBSS network, start beaconing
638 		 * only after a TSF-sync has taken place. Ensure that this
639 		 * happens by setting the appropriate flags.
640 		 */
641 		if ((changed & BSS_CHANGED_IBSS) && !bss_conf->ibss_creator &&
642 		    bss_conf->enable_beacon) {
643 			spin_lock_irqsave(&sc->sc_pm_lock, flags);
644 			sc->ps_flags |= PS_BEACON_SYNC | PS_WAIT_FOR_BEACON;
645 			spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
646 			skip_beacon = true;
647 		} else {
648 			ath9k_set_beacon(sc);
649 		}
650 
651 		/*
652 		 * Do not set the ATH_OP_BEACONS flag for IBSS joiner mode
653 		 * here, it is done in ath9k_beacon_config_adhoc().
654 		 */
655 		if (cur_conf->enable_beacon && !skip_beacon)
656 			set_bit(ATH_OP_BEACONS, &common->op_flags);
657 		else
658 			clear_bit(ATH_OP_BEACONS, &common->op_flags);
659 	}
660 }
661 
662 void ath9k_set_beacon(struct ath_softc *sc)
663 {
664 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
665 	struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;
666 
667 	switch (sc->sc_ah->opmode) {
668 	case NL80211_IFTYPE_AP:
669 	case NL80211_IFTYPE_MESH_POINT:
670 		ath9k_beacon_config_ap(sc, cur_conf);
671 		break;
672 	case NL80211_IFTYPE_ADHOC:
673 		ath9k_beacon_config_adhoc(sc, cur_conf);
674 		break;
675 	case NL80211_IFTYPE_STATION:
676 		ath9k_beacon_config_sta(sc->sc_ah, cur_conf);
677 		break;
678 	default:
679 		ath_dbg(common, CONFIG, "Unsupported beaconing mode\n");
680 		return;
681 	}
682 }
683