beacon.c 18.8 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686
/*
 * Copyright (c) 2008-2011 Atheros Communications Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/dma-mapping.h>
#include "ath9k.h"

#define FUDGE 2

static void ath9k_reset_beacon_status(struct ath_softc *sc)
{
	sc->beacon.tx_processed = false;
	sc->beacon.tx_last = false;
}

/*
 *  This function will modify certain transmit queue properties depending on
 *  the operating mode of the station (AP or AdHoc).  Parameters are AIFS
 *  settings and channel width min/max
*/
static void ath9k_beaconq_config(struct ath_softc *sc)
{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath9k_tx_queue_info qi, qi_be;
	struct ath_txq *txq;

	ath9k_hw_get_txq_props(ah, sc->beacon.beaconq, &qi);

	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP ||
	    sc->sc_ah->opmode == NL80211_IFTYPE_MESH_POINT) {
		/* Always burst out beacon and CAB traffic. */
		qi.tqi_aifs = 1;
		qi.tqi_cwmin = 0;
		qi.tqi_cwmax = 0;
	} else {
		/* Adhoc mode; important thing is to use 2x cwmin. */
		txq = sc->tx.txq_map[IEEE80211_AC_BE];
		ath9k_hw_get_txq_props(ah, txq->axq_qnum, &qi_be);
		qi.tqi_aifs = qi_be.tqi_aifs;
		if (ah->slottime == ATH9K_SLOT_TIME_20)
			qi.tqi_cwmin = 2*qi_be.tqi_cwmin;
		else
			qi.tqi_cwmin = 4*qi_be.tqi_cwmin;
		qi.tqi_cwmax = qi_be.tqi_cwmax;
	}

	if (!ath9k_hw_set_txq_props(ah, sc->beacon.beaconq, &qi)) {
		ath_err(common, "Unable to update h/w beacon queue parameters\n");
	} else {
		ath9k_hw_resettxqueue(ah, sc->beacon.beaconq);
	}
}

/*
 *  Associates the beacon frame buffer with a transmit descriptor.  Will set
 *  up rate codes, and channel flags. Beacons are always sent out at the
 *  lowest rate, and are not retried.
*/
static void ath9k_beacon_setup(struct ath_softc *sc, struct ieee80211_vif *vif,
			     struct ath_buf *bf, int rateidx)
{
	struct sk_buff *skb = bf->bf_mpdu;
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath_tx_info info;
	struct ieee80211_supported_band *sband;
	u8 chainmask = ah->txchainmask;
	u8 i, rate = 0;

	sband = &common->sbands[sc->cur_chandef.chan->band];
	rate = sband->bitrates[rateidx].hw_value;
	if (vif->bss_conf.use_short_preamble)
		rate |= sband->bitrates[rateidx].hw_value_short;

	memset(&info, 0, sizeof(info));
	info.pkt_len = skb->len + FCS_LEN;
	info.type = ATH9K_PKT_TYPE_BEACON;
	for (i = 0; i < 4; i++)
		info.txpower[i] = MAX_RATE_POWER;
	info.keyix = ATH9K_TXKEYIX_INVALID;
	info.keytype = ATH9K_KEY_TYPE_CLEAR;
	info.flags = ATH9K_TXDESC_NOACK | ATH9K_TXDESC_CLRDMASK;

	info.buf_addr[0] = bf->bf_buf_addr;
	info.buf_len[0] = roundup(skb->len, 4);

	info.is_first = true;
	info.is_last = true;

	info.qcu = sc->beacon.beaconq;

	info.rates[0].Tries = 1;
	info.rates[0].Rate = rate;
	info.rates[0].ChSel = ath_txchainmask_reduction(sc, chainmask, rate);

	ath9k_hw_set_txdesc(ah, bf->bf_desc, &info);
}

static struct ath_buf *ath9k_beacon_generate(struct ieee80211_hw *hw,
					     struct ieee80211_vif *vif)
{
	struct ath_softc *sc = hw->priv;
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_buf *bf;
	struct ath_vif *avp = (void *)vif->drv_priv;
	struct sk_buff *skb;
	struct ath_txq *cabq = sc->beacon.cabq;
	struct ieee80211_tx_info *info;
	struct ieee80211_mgmt *mgmt_hdr;
	int cabq_depth;

	if (avp->av_bcbuf == NULL)
		return NULL;

	bf = avp->av_bcbuf;
	skb = bf->bf_mpdu;
	if (skb) {
		dma_unmap_single(sc->dev, bf->bf_buf_addr,
				 skb->len, DMA_TO_DEVICE);
		dev_kfree_skb_any(skb);
		bf->bf_buf_addr = 0;
		bf->bf_mpdu = NULL;
	}

	skb = ieee80211_beacon_get(hw, vif);
	if (skb == NULL)
		return NULL;

	bf->bf_mpdu = skb;

	mgmt_hdr = (struct ieee80211_mgmt *)skb->data;
	mgmt_hdr->u.beacon.timestamp = avp->tsf_adjust;

	info = IEEE80211_SKB_CB(skb);

	ath_assign_seq(common, skb);

	if (vif->p2p)
		ath9k_beacon_add_noa(sc, avp, skb);

	bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
					 skb->len, DMA_TO_DEVICE);
	if (unlikely(dma_mapping_error(sc->dev, bf->bf_buf_addr))) {
		dev_kfree_skb_any(skb);
		bf->bf_mpdu = NULL;
		bf->bf_buf_addr = 0;
		ath_err(common, "dma_mapping_error on beaconing\n");
		return NULL;
	}

	skb = ieee80211_get_buffered_bc(hw, vif);

	/*
	 * if the CABQ traffic from previous DTIM is pending and the current
	 *  beacon is also a DTIM.
	 *  1) if there is only one vif let the cab traffic continue.
	 *  2) if there are more than one vif and we are using staggered
	 *     beacons, then drain the cabq by dropping all the frames in
	 *     the cabq so that the current vifs cab traffic can be scheduled.
	 */
	spin_lock_bh(&cabq->axq_lock);
	cabq_depth = cabq->axq_depth;
	spin_unlock_bh(&cabq->axq_lock);

	if (skb && cabq_depth) {
		if (sc->cur_chan->nvifs > 1) {
			ath_dbg(common, BEACON,
				"Flushing previous cabq traffic\n");
			ath_draintxq(sc, cabq);
		}
	}

	ath9k_beacon_setup(sc, vif, bf, info->control.rates[0].idx);

	if (skb)
		ath_tx_cabq(hw, vif, skb);

	return bf;
}

void ath9k_beacon_assign_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif *avp = (void *)vif->drv_priv;
	int slot;

	avp->av_bcbuf = list_first_entry(&sc->beacon.bbuf, struct ath_buf, list);
	list_del(&avp->av_bcbuf->list);

	for (slot = 0; slot < ATH_BCBUF; slot++) {
		if (sc->beacon.bslot[slot] == NULL) {
			avp->av_bslot = slot;
			break;
		}
	}

	sc->beacon.bslot[avp->av_bslot] = vif;
	sc->nbcnvifs++;

	ath_dbg(common, CONFIG, "Added interface at beacon slot: %d\n",
		avp->av_bslot);
}

void ath9k_beacon_remove_slot(struct ath_softc *sc, struct ieee80211_vif *vif)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif *avp = (void *)vif->drv_priv;
	struct ath_buf *bf = avp->av_bcbuf;
	struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;

	ath_dbg(common, CONFIG, "Removing interface at beacon slot: %d\n",
		avp->av_bslot);

	tasklet_disable(&sc->bcon_tasklet);

	cur_conf->enable_beacon &= ~BIT(avp->av_bslot);

	if (bf && bf->bf_mpdu) {
		struct sk_buff *skb = bf->bf_mpdu;
		dma_unmap_single(sc->dev, bf->bf_buf_addr,
				 skb->len, DMA_TO_DEVICE);
		dev_kfree_skb_any(skb);
		bf->bf_mpdu = NULL;
		bf->bf_buf_addr = 0;
	}

	avp->av_bcbuf = NULL;
	sc->beacon.bslot[avp->av_bslot] = NULL;
	sc->nbcnvifs--;
	list_add_tail(&bf->list, &sc->beacon.bbuf);

	tasklet_enable(&sc->bcon_tasklet);
}

static int ath9k_beacon_choose_slot(struct ath_softc *sc)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;
	u16 intval;
	u32 tsftu;
	u64 tsf;
	int slot;

	if (sc->sc_ah->opmode != NL80211_IFTYPE_AP &&
	    sc->sc_ah->opmode != NL80211_IFTYPE_MESH_POINT) {
		ath_dbg(common, BEACON, "slot 0, tsf: %llu\n",
			ath9k_hw_gettsf64(sc->sc_ah));
		return 0;
	}

	intval = cur_conf->beacon_interval ? : ATH_DEFAULT_BINTVAL;
	tsf = ath9k_hw_gettsf64(sc->sc_ah);
	tsf += TU_TO_USEC(sc->sc_ah->config.sw_beacon_response_time);
	tsftu = TSF_TO_TU((tsf * ATH_BCBUF) >>32, tsf * ATH_BCBUF);
	slot = (tsftu % (intval * ATH_BCBUF)) / intval;

	ath_dbg(common, BEACON, "slot: %d tsf: %llu tsftu: %u\n",
		slot, tsf, tsftu / ATH_BCBUF);

	return slot;
}

static void ath9k_set_tsfadjust(struct ath_softc *sc, struct ieee80211_vif *vif)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif *avp = (void *)vif->drv_priv;
	struct ath_beacon_config *cur_conf = &avp->chanctx->beacon;
	u32 tsfadjust;

	if (avp->av_bslot == 0)
		return;

	tsfadjust = cur_conf->beacon_interval * avp->av_bslot;
	tsfadjust = TU_TO_USEC(tsfadjust) / ATH_BCBUF;
	avp->tsf_adjust = cpu_to_le64(tsfadjust);

	ath_dbg(common, CONFIG, "tsfadjust is: %llu for bslot: %d\n",
		(unsigned long long)tsfadjust, avp->av_bslot);
}

bool ath9k_csa_is_finished(struct ath_softc *sc, struct ieee80211_vif *vif)
{
	if (!vif || !vif->csa_active)
		return false;

	if (!ieee80211_csa_is_complete(vif))
		return false;

	ieee80211_csa_finish(vif);
	return true;
}

static void ath9k_csa_update_vif(void *data, u8 *mac, struct ieee80211_vif *vif)
{
	struct ath_softc *sc = data;
	ath9k_csa_is_finished(sc, vif);
}

void ath9k_csa_update(struct ath_softc *sc)
{
	ieee80211_iterate_active_interfaces_atomic(sc->hw,
						   IEEE80211_IFACE_ITER_NORMAL,
						   ath9k_csa_update_vif, sc);
}

void ath9k_beacon_tasklet(unsigned long data)
{
	struct ath_softc *sc = (struct ath_softc *)data;
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);
	struct ath_buf *bf = NULL;
	struct ieee80211_vif *vif;
	bool edma = !!(ah->caps.hw_caps & ATH9K_HW_CAP_EDMA);
	int slot;

	if (test_bit(ATH_OP_HW_RESET, &common->op_flags)) {
		ath_dbg(common, RESET,
			"reset work is pending, skip beaconing now\n");
		return;
	}

	/*
	 * Check if the previous beacon has gone out.  If
	 * not don't try to post another, skip this period
	 * and wait for the next.  Missed beacons indicate
	 * a problem and should not occur.  If we miss too
	 * many consecutive beacons reset the device.
	 */
	if (ath9k_hw_numtxpending(ah, sc->beacon.beaconq) != 0) {
		sc->beacon.bmisscnt++;

		ath9k_hw_check_nav(ah);

		/*
		 * If the previous beacon has not been transmitted
		 * and a MAC/BB hang has been identified, return
		 * here because a chip reset would have been
		 * initiated.
		 */
		if (!ath_hw_check(sc))
			return;

		if (sc->beacon.bmisscnt < BSTUCK_THRESH * sc->nbcnvifs) {
			ath_dbg(common, BSTUCK,
				"missed %u consecutive beacons\n",
				sc->beacon.bmisscnt);
			ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
			if (sc->beacon.bmisscnt > 3)
				ath9k_hw_bstuck_nfcal(ah);
		} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
			ath_dbg(common, BSTUCK, "beacon is officially stuck\n");
			sc->beacon.bmisscnt = 0;
			ath9k_queue_reset(sc, RESET_TYPE_BEACON_STUCK);
		}

		return;
	}

	slot = ath9k_beacon_choose_slot(sc);
	vif = sc->beacon.bslot[slot];

	/* EDMA devices check that in the tx completion function. */
	if (!edma) {
		if (ath9k_is_chanctx_enabled()) {
			ath_chanctx_beacon_sent_ev(sc,
					  ATH_CHANCTX_EVENT_BEACON_SENT);
		}

		if (ath9k_csa_is_finished(sc, vif))
			return;
	}

	if (!vif || !vif->bss_conf.enable_beacon)
		return;

	if (ath9k_is_chanctx_enabled()) {
		ath_chanctx_event(sc, vif, ATH_CHANCTX_EVENT_BEACON_PREPARE);
	}

	bf = ath9k_beacon_generate(sc->hw, vif);

	if (sc->beacon.bmisscnt != 0) {
		ath_dbg(common, BSTUCK, "resume beacon xmit after %u misses\n",
			sc->beacon.bmisscnt);
		sc->beacon.bmisscnt = 0;
	}

	/*
	 * Handle slot time change when a non-ERP station joins/leaves
	 * an 11g network.  The 802.11 layer notifies us via callback,
	 * we mark updateslot, then wait one beacon before effecting
	 * the change.  This gives associated stations at least one
	 * beacon interval to note the state change.
	 *
	 * NB: The slot time change state machine is clocked according
	 *     to whether we are bursting or staggering beacons.  We
	 *     recognize the request to update and record the current
	 *     slot then don't transition until that slot is reached
	 *     again.  If we miss a beacon for that slot then we'll be
	 *     slow to transition but we'll be sure at least one beacon
	 *     interval has passed.  When bursting slot is always left
	 *     set to ATH_BCBUF so this check is a noop.
	 */
	if (sc->beacon.updateslot == UPDATE) {
		sc->beacon.updateslot = COMMIT;
		sc->beacon.slotupdate = slot;
	} else if (sc->beacon.updateslot == COMMIT &&
		   sc->beacon.slotupdate == slot) {
		ah->slottime = sc->beacon.slottime;
		ath9k_hw_init_global_settings(ah);
		sc->beacon.updateslot = OK;
	}

	if (bf) {
		ath9k_reset_beacon_status(sc);

		ath_dbg(common, BEACON,
			"Transmitting beacon for slot: %d\n", slot);

		/* NB: cabq traffic should already be queued and primed */
		ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bf->bf_daddr);

		if (!edma)
			ath9k_hw_txstart(ah, sc->beacon.beaconq);
	}
}

/*
 * Both nexttbtt and intval have to be in usecs.
 */
static void ath9k_beacon_init(struct ath_softc *sc, u32 nexttbtt,
			      u32 intval, bool reset_tsf)
{
	struct ath_hw *ah = sc->sc_ah;

	ath9k_hw_disable_interrupts(ah);
	if (reset_tsf)
		ath9k_hw_reset_tsf(ah);
	ath9k_beaconq_config(sc);
	ath9k_hw_beaconinit(ah, nexttbtt, intval);
	sc->beacon.bmisscnt = 0;
	ath9k_hw_set_interrupts(ah);
	ath9k_hw_enable_interrupts(ah);
}

/*
 * For multi-bss ap support beacons are either staggered evenly over N slots or
 * burst together.  For the former arrange for the SWBA to be delivered for each
 * slot. Slots that are not occupied will generate nothing.
 */
static void ath9k_beacon_config_ap(struct ath_softc *sc,
				   struct ath_beacon_config *conf)
{
	struct ath_hw *ah = sc->sc_ah;

	ath9k_cmn_beacon_config_ap(ah, conf, ATH_BCBUF);
	ath9k_beacon_init(sc, conf->nexttbtt, conf->intval, false);
}

static void ath9k_beacon_config_sta(struct ath_hw *ah,
				    struct ath_beacon_config *conf)
{
	struct ath9k_beacon_state bs;

	if (ath9k_cmn_beacon_config_sta(ah, conf, &bs) == -EPERM)
		return;

	ath9k_hw_disable_interrupts(ah);
	ath9k_hw_set_sta_beacon_timers(ah, &bs);
	ah->imask |= ATH9K_INT_BMISS;

	ath9k_hw_set_interrupts(ah);
	ath9k_hw_enable_interrupts(ah);
}

static void ath9k_beacon_config_adhoc(struct ath_softc *sc,
				      struct ath_beacon_config *conf)
{
	struct ath_hw *ah = sc->sc_ah;
	struct ath_common *common = ath9k_hw_common(ah);

	ath9k_reset_beacon_status(sc);

	ath9k_cmn_beacon_config_adhoc(ah, conf);

	ath9k_beacon_init(sc, conf->nexttbtt, conf->intval, conf->ibss_creator);

	/*
	 * Set the global 'beacon has been configured' flag for the
	 * joiner case in IBSS mode.
	 */
	if (!conf->ibss_creator && conf->enable_beacon)
		set_bit(ATH_OP_BEACONS, &common->op_flags);
}

static bool ath9k_allow_beacon_config(struct ath_softc *sc,
				      struct ieee80211_vif *vif)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_vif *avp = (void *)vif->drv_priv;

	if (ath9k_is_chanctx_enabled()) {
		/*
		 * If the VIF is not present in the current channel context,
		 * then we can't do the usual opmode checks. Allow the
		 * beacon config for the VIF to be updated in this case and
		 * return immediately.
		 */
		if (sc->cur_chan != avp->chanctx)
			return true;
	}

	if (sc->sc_ah->opmode == NL80211_IFTYPE_AP) {
		if (vif->type != NL80211_IFTYPE_AP) {
			ath_dbg(common, CONFIG,
				"An AP interface is already present !\n");
			return false;
		}
	}

	if (sc->sc_ah->opmode == NL80211_IFTYPE_STATION) {
		if ((vif->type == NL80211_IFTYPE_STATION) &&
		    test_bit(ATH_OP_BEACONS, &common->op_flags) &&
		    vif != sc->cur_chan->primary_sta) {
			ath_dbg(common, CONFIG,
				"Beacon already configured for a station interface\n");
			return false;
		}
	}

	return true;
}

static void ath9k_cache_beacon_config(struct ath_softc *sc,
				      struct ath_chanctx *ctx,
				      struct ieee80211_bss_conf *bss_conf)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &ctx->beacon;

	ath_dbg(common, BEACON,
		"Caching beacon data for BSS: %pM\n", bss_conf->bssid);

	cur_conf->beacon_interval = bss_conf->beacon_int;
	cur_conf->dtim_period = bss_conf->dtim_period;
	cur_conf->dtim_count = 1;
	cur_conf->ibss_creator = bss_conf->ibss_creator;

	/*
	 * It looks like mac80211 may end up using beacon interval of zero in
	 * some cases (at least for mesh point). Avoid getting into an
	 * infinite loop by using a bit safer value instead. To be safe,
	 * do sanity check on beacon interval for all operating modes.
	 */
	if (cur_conf->beacon_interval == 0)
		cur_conf->beacon_interval = 100;

	cur_conf->bmiss_timeout =
		ATH_DEFAULT_BMISS_LIMIT * cur_conf->beacon_interval;

	/*
	 * We don't parse dtim period from mac80211 during the driver
	 * initialization as it breaks association with hidden-ssid
	 * AP and it causes latency in roaming
	 */
	if (cur_conf->dtim_period == 0)
		cur_conf->dtim_period = 1;

}

void ath9k_beacon_config(struct ath_softc *sc, struct ieee80211_vif *vif,
			 u32 changed)
{
	struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
	struct ath_vif *avp = (void *)vif->drv_priv;
	struct ath_chanctx *ctx = avp->chanctx;
	struct ath_beacon_config *cur_conf;
	unsigned long flags;
	bool skip_beacon = false;

	if (!ctx)
		return;

	cur_conf = &avp->chanctx->beacon;
	if (vif->type == NL80211_IFTYPE_AP)
		ath9k_set_tsfadjust(sc, vif);

	if (!ath9k_allow_beacon_config(sc, vif))
		return;

	if (vif->type == NL80211_IFTYPE_STATION) {
		ath9k_cache_beacon_config(sc, ctx, bss_conf);
		if (ctx != sc->cur_chan)
			return;

		ath9k_set_beacon(sc);
		set_bit(ATH_OP_BEACONS, &common->op_flags);
		return;
	}

	/*
	 * Take care of multiple interfaces when
	 * enabling/disabling SWBA.
	 */
	if (changed & BSS_CHANGED_BEACON_ENABLED) {
		bool enabled = cur_conf->enable_beacon;

		if (!bss_conf->enable_beacon) {
			cur_conf->enable_beacon &= ~BIT(avp->av_bslot);
		} else {
			cur_conf->enable_beacon |= BIT(avp->av_bslot);
			if (!enabled)
				ath9k_cache_beacon_config(sc, ctx, bss_conf);
		}
	}

	if (ctx != sc->cur_chan)
		return;

	/*
	 * Configure the HW beacon registers only when we have a valid
	 * beacon interval.
	 */
	if (cur_conf->beacon_interval) {
		/*
		 * If we are joining an existing IBSS network, start beaconing
		 * only after a TSF-sync has taken place. Ensure that this
		 * happens by setting the appropriate flags.
		 */
		if ((changed & BSS_CHANGED_IBSS) && !bss_conf->ibss_creator &&
		    bss_conf->enable_beacon) {
			spin_lock_irqsave(&sc->sc_pm_lock, flags);
			sc->ps_flags |= PS_BEACON_SYNC | PS_WAIT_FOR_BEACON;
			spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
			skip_beacon = true;
		} else {
			ath9k_set_beacon(sc);
		}

		/*
		 * Do not set the ATH_OP_BEACONS flag for IBSS joiner mode
		 * here, it is done in ath9k_beacon_config_adhoc().
		 */
		if (cur_conf->enable_beacon && !skip_beacon)
			set_bit(ATH_OP_BEACONS, &common->op_flags);
		else
			clear_bit(ATH_OP_BEACONS, &common->op_flags);
	}
}

void ath9k_set_beacon(struct ath_softc *sc)
{
	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
	struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;

	switch (sc->sc_ah->opmode) {
	case NL80211_IFTYPE_AP:
	case NL80211_IFTYPE_MESH_POINT:
		ath9k_beacon_config_ap(sc, cur_conf);
		break;
	case NL80211_IFTYPE_ADHOC:
		ath9k_beacon_config_adhoc(sc, cur_conf);
		break;
	case NL80211_IFTYPE_STATION:
		ath9k_beacon_config_sta(sc->sc_ah, cur_conf);
		break;
	default:
		ath_dbg(common, CONFIG, "Unsupported beaconing mode\n");
		return;
	}
}