xref: /freebsd/sys/dev/ath/if_ath_tdma.c (revision a0409676120c1e558d0ade943019934e0f15118d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer,
12  *    without modification.
13  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
14  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
15  *    redistribution must be conditioned upon including a substantially
16  *    similar Disclaimer requirement for further binary redistribution.
17  *
18  * NO WARRANTY
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
22  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
23  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
24  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
27  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
29  * THE POSSIBILITY OF SUCH DAMAGES.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 /*
36  * Driver for the Atheros Wireless LAN controller.
37  *
38  * This software is derived from work of Atsushi Onoe; his contribution
39  * is greatly appreciated.
40  */
41 
42 #include "opt_inet.h"
43 #include "opt_ath.h"
44 /*
45  * This is needed for register operations which are performed
46  * by the driver - eg, calls to ath_hal_gettsf32().
47  *
48  * It's also required for any AH_DEBUG checks in here, eg the
49  * module dependencies.
50  */
51 #include "opt_ah.h"
52 #include "opt_wlan.h"
53 
54 #include <sys/param.h>
55 #include <sys/systm.h>
56 #include <sys/sysctl.h>
57 #include <sys/mbuf.h>
58 #include <sys/malloc.h>
59 #include <sys/lock.h>
60 #include <sys/mutex.h>
61 #include <sys/kernel.h>
62 #include <sys/socket.h>
63 #include <sys/sockio.h>
64 #include <sys/errno.h>
65 #include <sys/callout.h>
66 #include <sys/bus.h>
67 #include <sys/endian.h>
68 #include <sys/kthread.h>
69 #include <sys/taskqueue.h>
70 #include <sys/priv.h>
71 #include <sys/module.h>
72 #include <sys/ktr.h>
73 #include <sys/smp.h>	/* for mp_ncpus */
74 
75 #include <machine/bus.h>
76 
77 #include <net/if.h>
78 #include <net/if_var.h>
79 #include <net/if_dl.h>
80 #include <net/if_media.h>
81 #include <net/if_types.h>
82 #include <net/if_arp.h>
83 #include <net/ethernet.h>
84 #include <net/if_llc.h>
85 
86 #include <net80211/ieee80211_var.h>
87 #include <net80211/ieee80211_regdomain.h>
88 #ifdef IEEE80211_SUPPORT_SUPERG
89 #include <net80211/ieee80211_superg.h>
90 #endif
91 #ifdef IEEE80211_SUPPORT_TDMA
92 #include <net80211/ieee80211_tdma.h>
93 #endif
94 
95 #include <net/bpf.h>
96 
97 #ifdef INET
98 #include <netinet/in.h>
99 #include <netinet/if_ether.h>
100 #endif
101 
102 #include <dev/ath/if_athvar.h>
103 #include <dev/ath/ath_hal/ah_devid.h>		/* XXX for softled */
104 #include <dev/ath/ath_hal/ah_diagcodes.h>
105 
106 #include <dev/ath/if_ath_debug.h>
107 #include <dev/ath/if_ath_misc.h>
108 #include <dev/ath/if_ath_tsf.h>
109 #include <dev/ath/if_ath_tx.h>
110 #include <dev/ath/if_ath_sysctl.h>
111 #include <dev/ath/if_ath_led.h>
112 #include <dev/ath/if_ath_keycache.h>
113 #include <dev/ath/if_ath_rx.h>
114 #include <dev/ath/if_ath_beacon.h>
115 #include <dev/ath/if_athdfs.h>
116 
117 #ifdef ATH_TX99_DIAG
118 #include <dev/ath/ath_tx99/ath_tx99.h>
119 #endif
120 
121 #ifdef	ATH_DEBUG_ALQ
122 #include <dev/ath/if_ath_alq.h>
123 #endif
124 
125 #ifdef IEEE80211_SUPPORT_TDMA
126 #include <dev/ath/if_ath_tdma.h>
127 
128 static void	ath_tdma_settimers(struct ath_softc *sc, u_int32_t nexttbtt,
129 		    u_int32_t bintval);
130 static void	ath_tdma_bintvalsetup(struct ath_softc *sc,
131 		    const struct ieee80211_tdma_state *tdma);
132 #endif /* IEEE80211_SUPPORT_TDMA */
133 
134 #ifdef IEEE80211_SUPPORT_TDMA
135 static void
136 ath_tdma_settimers(struct ath_softc *sc, u_int32_t nexttbtt, u_int32_t bintval)
137 {
138 	struct ath_hal *ah = sc->sc_ah;
139 	HAL_BEACON_TIMERS bt;
140 
141 	bt.bt_intval = bintval | HAL_BEACON_ENA;
142 	bt.bt_nexttbtt = nexttbtt;
143 	bt.bt_nextdba = (nexttbtt<<3) - sc->sc_tdmadbaprep;
144 	bt.bt_nextswba = (nexttbtt<<3) - sc->sc_tdmaswbaprep;
145 	bt.bt_nextatim = nexttbtt+1;
146 	/* Enables TBTT, DBA, SWBA timers by default */
147 	bt.bt_flags = 0;
148 #if 0
149 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
150 	    "%s: intval=%d (0x%08x) nexttbtt=%u (0x%08x), nextdba=%u (0x%08x), nextswba=%u (0x%08x),nextatim=%u (0x%08x)\n",
151 	    __func__,
152 	    bt.bt_intval,
153 	    bt.bt_intval,
154 	    bt.bt_nexttbtt,
155 	    bt.bt_nexttbtt,
156 	    bt.bt_nextdba,
157 	    bt.bt_nextdba,
158 	    bt.bt_nextswba,
159 	    bt.bt_nextswba,
160 	    bt.bt_nextatim,
161 	    bt.bt_nextatim);
162 #endif
163 
164 #ifdef	ATH_DEBUG_ALQ
165 	if (if_ath_alq_checkdebug(&sc->sc_alq, ATH_ALQ_TDMA_TIMER_SET)) {
166 		struct if_ath_alq_tdma_timer_set t;
167 		t.bt_intval = htobe32(bt.bt_intval);
168 		t.bt_nexttbtt = htobe32(bt.bt_nexttbtt);
169 		t.bt_nextdba = htobe32(bt.bt_nextdba);
170 		t.bt_nextswba = htobe32(bt.bt_nextswba);
171 		t.bt_nextatim = htobe32(bt.bt_nextatim);
172 		t.bt_flags = htobe32(bt.bt_flags);
173 		t.sc_tdmadbaprep = htobe32(sc->sc_tdmadbaprep);
174 		t.sc_tdmaswbaprep = htobe32(sc->sc_tdmaswbaprep);
175 		if_ath_alq_post(&sc->sc_alq, ATH_ALQ_TDMA_TIMER_SET,
176 		    sizeof(t), (char *) &t);
177 	}
178 #endif
179 
180 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
181 	    "%s: nexttbtt=%u (0x%08x), nexttbtt tsf=%lld (0x%08llx)\n",
182 	    __func__,
183 	    bt.bt_nexttbtt,
184 	    bt.bt_nexttbtt,
185 	    (long long) ( ((u_int64_t) (bt.bt_nexttbtt)) << 10),
186 	    (long long) ( ((u_int64_t) (bt.bt_nexttbtt)) << 10));
187 	ath_hal_beaconsettimers(ah, &bt);
188 }
189 
190 /*
191  * Calculate the beacon interval.  This is periodic in the
192  * superframe for the bss.  We assume each station is configured
193  * identically wrt transmit rate so the guard time we calculate
194  * above will be the same on all stations.  Note we need to
195  * factor in the xmit time because the hardware will schedule
196  * a frame for transmit if the start of the frame is within
197  * the burst time.  When we get hardware that properly kills
198  * frames in the PCU we can reduce/eliminate the guard time.
199  *
200  * Roundup to 1024 is so we have 1 TU buffer in the guard time
201  * to deal with the granularity of the nexttbtt timer.  11n MAC's
202  * with 1us timer granularity should allow us to reduce/eliminate
203  * this.
204  */
205 static void
206 ath_tdma_bintvalsetup(struct ath_softc *sc,
207 	const struct ieee80211_tdma_state *tdma)
208 {
209 	/* copy from vap state (XXX check all vaps have same value?) */
210 	sc->sc_tdmaslotlen = tdma->tdma_slotlen;
211 
212 	sc->sc_tdmabintval = roundup((sc->sc_tdmaslotlen+sc->sc_tdmaguard) *
213 		tdma->tdma_slotcnt, 1024);
214 	sc->sc_tdmabintval >>= 10;		/* TSF -> TU */
215 	if (sc->sc_tdmabintval & 1)
216 		sc->sc_tdmabintval++;
217 
218 	if (tdma->tdma_slot == 0) {
219 		/*
220 		 * Only slot 0 beacons; other slots respond.
221 		 */
222 		sc->sc_imask |= HAL_INT_SWBA;
223 		sc->sc_tdmaswba = 0;		/* beacon immediately */
224 	} else {
225 		/* XXX all vaps must be slot 0 or slot !0 */
226 		sc->sc_imask &= ~HAL_INT_SWBA;
227 	}
228 }
229 
230 /*
231  * Max 802.11 overhead.  This assumes no 4-address frames and
232  * the encapsulation done by ieee80211_encap (llc).  We also
233  * include potential crypto overhead.
234  */
235 #define	IEEE80211_MAXOVERHEAD \
236 	(sizeof(struct ieee80211_qosframe) \
237 	 + sizeof(struct llc) \
238 	 + IEEE80211_ADDR_LEN \
239 	 + IEEE80211_WEP_IVLEN \
240 	 + IEEE80211_WEP_KIDLEN \
241 	 + IEEE80211_WEP_CRCLEN \
242 	 + IEEE80211_WEP_MICLEN \
243 	 + IEEE80211_CRC_LEN)
244 
245 /*
246  * Setup initially for tdma operation.  Start the beacon
247  * timers and enable SWBA if we are slot 0.  Otherwise
248  * we wait for slot 0 to arrive so we can sync up before
249  * starting to transmit.
250  */
251 void
252 ath_tdma_config(struct ath_softc *sc, struct ieee80211vap *vap)
253 {
254 	struct ath_hal *ah = sc->sc_ah;
255 	struct ieee80211com *ic = &sc->sc_ic;
256 	const struct ieee80211_txparam *tp;
257 	const struct ieee80211_tdma_state *tdma = NULL;
258 	int rix;
259 
260 	if (vap == NULL) {
261 		vap = TAILQ_FIRST(&ic->ic_vaps);   /* XXX */
262 		if (vap == NULL) {
263 			device_printf(sc->sc_dev, "%s: no vaps?\n", __func__);
264 			return;
265 		}
266 	}
267 	/* XXX should take a locked ref to iv_bss */
268 	tp = vap->iv_bss->ni_txparms;
269 	/*
270 	 * Calculate the guard time for each slot.  This is the
271 	 * time to send a maximal-size frame according to the
272 	 * fixed/lowest transmit rate.  Note that the interface
273 	 * mtu does not include the 802.11 overhead so we must
274 	 * tack that on (ath_hal_computetxtime includes the
275 	 * preamble and plcp in its calculation).
276 	 */
277 	tdma = vap->iv_tdma;
278 	if (tp->ucastrate != IEEE80211_FIXED_RATE_NONE)
279 		rix = ath_tx_findrix(sc, tp->ucastrate);
280 	else
281 		rix = ath_tx_findrix(sc, tp->mcastrate);
282 
283 	/*
284 	 * If the chip supports enforcing TxOP on transmission,
285 	 * we can just delete the guard window.  It isn't at all required.
286 	 */
287 	if (sc->sc_hasenforcetxop) {
288 		sc->sc_tdmaguard = 0;
289 	} else {
290 		/* XXX short preamble assumed */
291 		/* XXX non-11n rate assumed */
292 		sc->sc_tdmaguard = ath_hal_computetxtime(ah, sc->sc_currates,
293 		    vap->iv_ifp->if_mtu + IEEE80211_MAXOVERHEAD, rix, AH_TRUE,
294 		    AH_TRUE);
295 	}
296 
297 	ath_hal_intrset(ah, 0);
298 
299 	ath_beaconq_config(sc);			/* setup h/w beacon q */
300 	if (sc->sc_setcca)
301 		ath_hal_setcca(ah, AH_FALSE);	/* disable CCA */
302 	ath_tdma_bintvalsetup(sc, tdma);	/* calculate beacon interval */
303 	ath_tdma_settimers(sc, sc->sc_tdmabintval,
304 		sc->sc_tdmabintval | HAL_BEACON_RESET_TSF);
305 	sc->sc_syncbeacon = 0;
306 
307 	sc->sc_avgtsfdeltap = TDMA_DUMMY_MARKER;
308 	sc->sc_avgtsfdeltam = TDMA_DUMMY_MARKER;
309 
310 	ath_hal_intrset(ah, sc->sc_imask);
311 
312 	DPRINTF(sc, ATH_DEBUG_TDMA, "%s: slot %u len %uus cnt %u "
313 	    "bsched %u guard %uus bintval %u TU dba prep %u\n", __func__,
314 	    tdma->tdma_slot, tdma->tdma_slotlen, tdma->tdma_slotcnt,
315 	    tdma->tdma_bintval, sc->sc_tdmaguard, sc->sc_tdmabintval,
316 	    sc->sc_tdmadbaprep);
317 
318 #ifdef	ATH_DEBUG_ALQ
319 	if (if_ath_alq_checkdebug(&sc->sc_alq, ATH_ALQ_TDMA_TIMER_CONFIG)) {
320 		struct if_ath_alq_tdma_timer_config t;
321 
322 		t.tdma_slot = htobe32(tdma->tdma_slot);
323 		t.tdma_slotlen = htobe32(tdma->tdma_slotlen);
324 		t.tdma_slotcnt = htobe32(tdma->tdma_slotcnt);
325 		t.tdma_bintval = htobe32(tdma->tdma_bintval);
326 		t.tdma_guard = htobe32(sc->sc_tdmaguard);
327 		t.tdma_scbintval = htobe32(sc->sc_tdmabintval);
328 		t.tdma_dbaprep = htobe32(sc->sc_tdmadbaprep);
329 
330 		if_ath_alq_post(&sc->sc_alq, ATH_ALQ_TDMA_TIMER_CONFIG,
331 		    sizeof(t), (char *) &t);
332 	}
333 #endif	/* ATH_DEBUG_ALQ */
334 }
335 
336 /*
337  * Update tdma operation.  Called from the 802.11 layer
338  * when a beacon is received from the TDMA station operating
339  * in the slot immediately preceding us in the bss.  Use
340  * the rx timestamp for the beacon frame to update our
341  * beacon timers so we follow their schedule.  Note that
342  * by using the rx timestamp we implicitly include the
343  * propagation delay in our schedule.
344  *
345  * XXX TODO: since the changes for the AR5416 and later chips
346  * involved changing the TSF/TU calculations, we need to make
347  * sure that various calculations wrap consistently.
348  *
349  * A lot of the problems stemmed from the calculations wrapping
350  * at 65,535 TU.  Since a lot of the math is still being done in
351  * TU, please audit it to ensure that when the TU values programmed
352  * into the timers wrap at (2^31)-1 TSF, all the various terms
353  * wrap consistently.
354  */
355 void
356 ath_tdma_update(struct ieee80211_node *ni,
357 	const struct ieee80211_tdma_param *tdma, int changed)
358 {
359 #define	TSF_TO_TU(_h,_l) \
360 	((((u_int32_t)(_h)) << 22) | (((u_int32_t)(_l)) >> 10))
361 #define	TU_TO_TSF(_tu)	(((u_int64_t)(_tu)) << 10)
362 	struct ieee80211vap *vap = ni->ni_vap;
363 	struct ieee80211com *ic = ni->ni_ic;
364 	struct ath_softc *sc = ic->ic_softc;
365 	struct ath_hal *ah = sc->sc_ah;
366 	const HAL_RATE_TABLE *rt = sc->sc_currates;
367 	u_int64_t tsf, rstamp, nextslot, nexttbtt, nexttbtt_full;
368 	u_int32_t txtime, nextslottu;
369 	int32_t tudelta, tsfdelta;
370 	const struct ath_rx_status *rs;
371 	int rix;
372 
373 	sc->sc_stats.ast_tdma_update++;
374 
375 	/*
376 	 * Check for and adopt configuration changes.
377 	 */
378 	if (changed != 0) {
379 		const struct ieee80211_tdma_state *ts = vap->iv_tdma;
380 
381 		ath_tdma_bintvalsetup(sc, ts);
382 		if (changed & TDMA_UPDATE_SLOTLEN)
383 			ath_wme_update(ic);
384 
385 		DPRINTF(sc, ATH_DEBUG_TDMA,
386 		    "%s: adopt slot %u slotcnt %u slotlen %u us "
387 		    "bintval %u TU\n", __func__,
388 		    ts->tdma_slot, ts->tdma_slotcnt, ts->tdma_slotlen,
389 		    sc->sc_tdmabintval);
390 
391 		/* XXX right? */
392 		ath_hal_intrset(ah, sc->sc_imask);
393 		/* NB: beacon timers programmed below */
394 	}
395 
396 	/* extend rx timestamp to 64 bits */
397 	rs = sc->sc_lastrs;
398 	tsf = ath_hal_gettsf64(ah);
399 	rstamp = ath_extend_tsf(sc, rs->rs_tstamp, tsf);
400 	/*
401 	 * The rx timestamp is set by the hardware on completing
402 	 * reception (at the point where the rx descriptor is DMA'd
403 	 * to the host).  To find the start of our next slot we
404 	 * must adjust this time by the time required to send
405 	 * the packet just received.
406 	 */
407 	rix = rt->rateCodeToIndex[rs->rs_rate];
408 
409 	/*
410 	 * To calculate the packet duration for legacy rates, we
411 	 * only need the rix and preamble.
412 	 *
413 	 * For 11n non-aggregate frames, we also need the channel
414 	 * width and short/long guard interval.
415 	 *
416 	 * For 11n aggregate frames, the required hacks are a little
417 	 * more subtle.  You need to figure out the frame duration
418 	 * for each frame, including the delimiters.  However, when
419 	 * a frame isn't received successfully, we won't hear it
420 	 * (unless you enable reception of CRC errored frames), so
421 	 * your duration calculation is going to be off.
422 	 *
423 	 * However, we can assume that the beacon frames won't be
424 	 * transmitted as aggregate frames, so we should be okay.
425 	 * Just add a check to ensure that we aren't handed something
426 	 * bad.
427 	 *
428 	 * For ath_hal_pkt_txtime() - for 11n rates, shortPreamble is
429 	 * actually short guard interval. For legacy rates,
430 	 * it's short preamble.
431 	 */
432 	txtime = ath_hal_pkt_txtime(ah, rt, rs->rs_datalen,
433 	    rix,
434 	    !! (rs->rs_flags & HAL_RX_2040),
435 	    (rix & 0x80) ?
436 	      (! (rs->rs_flags & HAL_RX_GI)) : rt->info[rix].shortPreamble,
437 	    AH_TRUE);
438 	/* NB: << 9 is to cvt to TU and /2 */
439 	nextslot = (rstamp - txtime) + (sc->sc_tdmabintval << 9);
440 
441 	/*
442 	 * For 802.11n chips: nextslottu needs to be the full TSF space,
443 	 * not just 0..65535 TU.
444 	 */
445 	nextslottu = TSF_TO_TU(nextslot>>32, nextslot);
446 	/*
447 	 * Retrieve the hardware NextTBTT in usecs
448 	 * and calculate the difference between what the
449 	 * other station thinks and what we have programmed.  This
450 	 * lets us figure how to adjust our timers to match.  The
451 	 * adjustments are done by pulling the TSF forward and possibly
452 	 * rewriting the beacon timers.
453 	 */
454 	/*
455 	 * The logic here assumes the nexttbtt counter is in TSF
456 	 * but the prr-11n NICs are in TU.  The HAL shifts them
457 	 * to TSF but there's two important differences:
458 	 *
459 	 * + The TU->TSF values have 0's for the low 9 bits, and
460 	 * + The counter wraps at TU_TO_TSF(HAL_BEACON_PERIOD + 1) for
461 	 *   the pre-11n NICs, but not for the 11n NICs.
462 	 *
463 	 * So for now, just make sure the nexttbtt value we get
464 	 * matches the second issue or once nexttbtt exceeds this
465 	 * value, tsfdelta ends up becoming very negative and all
466 	 * of the adjustments get very messed up.
467 	 */
468 
469 	/*
470 	 * We need to track the full nexttbtt rather than having it
471 	 * truncated at HAL_BEACON_PERIOD, as programming the
472 	 * nexttbtt (and related) registers for the 11n chips is
473 	 * actually going to take the full 32 bit space, rather than
474 	 * just 0..65535 TU.
475 	 */
476 	nexttbtt_full = ath_hal_getnexttbtt(ah);
477 	nexttbtt = nexttbtt_full % (TU_TO_TSF(HAL_BEACON_PERIOD + 1));
478 	tsfdelta = (int32_t)((nextslot % TU_TO_TSF(HAL_BEACON_PERIOD + 1)) - nexttbtt);
479 
480 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
481 	    "rs->rstamp %llu rstamp %llu tsf %llu txtime %d, nextslot %llu, "
482 	    "nextslottu %d, nextslottume %d\n",
483 	    (unsigned long long) rs->rs_tstamp,
484 	    (unsigned long long) rstamp,
485 	    (unsigned long long) tsf, txtime,
486 	    (unsigned long long) nextslot,
487 	    nextslottu, TSF_TO_TU(nextslot >> 32, nextslot));
488 	DPRINTF(sc, ATH_DEBUG_TDMA,
489 	    "  beacon tstamp: %llu (0x%016llx)\n",
490 	    (unsigned long long) le64toh(ni->ni_tstamp.tsf),
491 	    (unsigned long long) le64toh(ni->ni_tstamp.tsf));
492 
493 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
494 	    "nexttbtt %llu (0x%08llx) tsfdelta %d avg +%d/-%d\n",
495 	    (unsigned long long) nexttbtt,
496 	    (long long) nexttbtt,
497 	    tsfdelta,
498 	    TDMA_AVG(sc->sc_avgtsfdeltap), TDMA_AVG(sc->sc_avgtsfdeltam));
499 
500 	if (tsfdelta < 0) {
501 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, 0);
502 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, -tsfdelta);
503 		tsfdelta = -tsfdelta % 1024;
504 		nextslottu++;
505 	} else if (tsfdelta > 0) {
506 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, tsfdelta);
507 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, 0);
508 		tsfdelta = 1024 - (tsfdelta % 1024);
509 		nextslottu++;
510 	} else {
511 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, 0);
512 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, 0);
513 	}
514 	tudelta = nextslottu - TSF_TO_TU(nexttbtt_full >> 32, nexttbtt_full);
515 
516 #ifdef	ATH_DEBUG_ALQ
517 	if (if_ath_alq_checkdebug(&sc->sc_alq, ATH_ALQ_TDMA_BEACON_STATE)) {
518 		struct if_ath_alq_tdma_beacon_state t;
519 		t.rx_tsf = htobe64(rstamp);
520 		t.beacon_tsf = htobe64(le64toh(ni->ni_tstamp.tsf));
521 		t.tsf64 = htobe64(tsf);
522 		t.nextslot_tsf = htobe64(nextslot);
523 		t.nextslot_tu = htobe32(nextslottu);
524 		t.txtime = htobe32(txtime);
525 		if_ath_alq_post(&sc->sc_alq, ATH_ALQ_TDMA_BEACON_STATE,
526 		    sizeof(t), (char *) &t);
527 	}
528 
529 	if (if_ath_alq_checkdebug(&sc->sc_alq, ATH_ALQ_TDMA_SLOT_CALC)) {
530 		struct if_ath_alq_tdma_slot_calc t;
531 
532 		t.nexttbtt = htobe64(nexttbtt_full);
533 		t.next_slot = htobe64(nextslot);
534 		t.tsfdelta = htobe32(tsfdelta);
535 		t.avg_plus = htobe32(TDMA_AVG(sc->sc_avgtsfdeltap));
536 		t.avg_minus = htobe32(TDMA_AVG(sc->sc_avgtsfdeltam));
537 
538 		if_ath_alq_post(&sc->sc_alq, ATH_ALQ_TDMA_SLOT_CALC,
539 		    sizeof(t), (char *) &t);
540 	}
541 #endif
542 
543 	/*
544 	 * Copy sender's timetstamp into tdma ie so they can
545 	 * calculate roundtrip time.  We submit a beacon frame
546 	 * below after any timer adjustment.  The frame goes out
547 	 * at the next TBTT so the sender can calculate the
548 	 * roundtrip by inspecting the tdma ie in our beacon frame.
549 	 *
550 	 * NB: This tstamp is subtlely preserved when
551 	 *     IEEE80211_BEACON_TDMA is marked (e.g. when the
552 	 *     slot position changes) because ieee80211_add_tdma
553 	 *     skips over the data.
554 	 */
555 	memcpy(vap->iv_bcn_off.bo_tdma +
556 		__offsetof(struct ieee80211_tdma_param, tdma_tstamp),
557 		&ni->ni_tstamp.data, 8);
558 #if 0
559 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
560 	    "tsf %llu nextslot %llu (%d, %d) nextslottu %u nexttbtt %llu (%d)\n",
561 	    (unsigned long long) tsf, (unsigned long long) nextslot,
562 	    (int)(nextslot - tsf), tsfdelta, nextslottu, nexttbtt, tudelta);
563 #endif
564 	/*
565 	 * Adjust the beacon timers only when pulling them forward
566 	 * or when going back by less than the beacon interval.
567 	 * Negative jumps larger than the beacon interval seem to
568 	 * cause the timers to stop and generally cause instability.
569 	 * This basically filters out jumps due to missed beacons.
570 	 */
571 	if (tudelta != 0 && (tudelta > 0 || -tudelta < sc->sc_tdmabintval)) {
572 		DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
573 		    "%s: calling ath_tdma_settimers; nextslottu=%d, bintval=%d\n",
574 		    __func__,
575 		    nextslottu,
576 		    sc->sc_tdmabintval);
577 		ath_tdma_settimers(sc, nextslottu, sc->sc_tdmabintval);
578 		sc->sc_stats.ast_tdma_timers++;
579 	}
580 	if (tsfdelta > 0) {
581 		uint64_t tsf;
582 
583 		/* XXX should just teach ath_hal_adjusttsf() to do this */
584 		tsf = ath_hal_gettsf64(ah);
585 		ath_hal_settsf64(ah, tsf + tsfdelta);
586 		DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
587 		    "%s: calling ath_hal_adjusttsf: TSF=%llu, tsfdelta=%d\n",
588 		    __func__,
589 		    (unsigned long long) tsf,
590 		    tsfdelta);
591 
592 #ifdef	ATH_DEBUG_ALQ
593 		if (if_ath_alq_checkdebug(&sc->sc_alq,
594 		    ATH_ALQ_TDMA_TSF_ADJUST)) {
595 			struct if_ath_alq_tdma_tsf_adjust t;
596 
597 			t.tsfdelta = htobe32(tsfdelta);
598 			t.tsf64_old = htobe64(tsf);
599 			t.tsf64_new = htobe64(tsf + tsfdelta);
600 			if_ath_alq_post(&sc->sc_alq, ATH_ALQ_TDMA_TSF_ADJUST,
601 			    sizeof(t), (char *) &t);
602 		}
603 #endif	/* ATH_DEBUG_ALQ */
604 		sc->sc_stats.ast_tdma_tsf++;
605 	}
606 	ath_tdma_beacon_send(sc, vap);		/* prepare response */
607 #undef TU_TO_TSF
608 #undef TSF_TO_TU
609 }
610 
611 /*
612  * Transmit a beacon frame at SWBA.  Dynamic updates
613  * to the frame contents are done as needed.
614  */
615 void
616 ath_tdma_beacon_send(struct ath_softc *sc, struct ieee80211vap *vap)
617 {
618 	struct ath_hal *ah = sc->sc_ah;
619 	struct ath_buf *bf;
620 	int otherant;
621 
622 	/*
623 	 * Check if the previous beacon has gone out.  If
624 	 * not don't try to post another, skip this period
625 	 * and wait for the next.  Missed beacons indicate
626 	 * a problem and should not occur.  If we miss too
627 	 * many consecutive beacons reset the device.
628 	 */
629 	if (ath_hal_numtxpending(ah, sc->sc_bhalq) != 0) {
630 		sc->sc_bmisscount++;
631 		DPRINTF(sc, ATH_DEBUG_BEACON,
632 			"%s: missed %u consecutive beacons\n",
633 			__func__, sc->sc_bmisscount);
634 		if (sc->sc_bmisscount >= ath_bstuck_threshold)
635 			taskqueue_enqueue(sc->sc_tq, &sc->sc_bstucktask);
636 		return;
637 	}
638 	if (sc->sc_bmisscount != 0) {
639 		DPRINTF(sc, ATH_DEBUG_BEACON,
640 			"%s: resume beacon xmit after %u misses\n",
641 			__func__, sc->sc_bmisscount);
642 		sc->sc_bmisscount = 0;
643 	}
644 
645 	/*
646 	 * Check recent per-antenna transmit statistics and flip
647 	 * the default antenna if noticeably more frames went out
648 	 * on the non-default antenna.
649 	 * XXX assumes 2 anntenae
650 	 */
651 	if (!sc->sc_diversity) {
652 		otherant = sc->sc_defant & 1 ? 2 : 1;
653 		if (sc->sc_ant_tx[otherant] > sc->sc_ant_tx[sc->sc_defant] + 2)
654 			ath_setdefantenna(sc, otherant);
655 		sc->sc_ant_tx[1] = sc->sc_ant_tx[2] = 0;
656 	}
657 
658 	bf = ath_beacon_generate(sc, vap);
659 	/* XXX We don't do cabq traffic, but just for completeness .. */
660 	ATH_TXQ_LOCK(sc->sc_cabq);
661 	ath_beacon_cabq_start(sc);
662 	ATH_TXQ_UNLOCK(sc->sc_cabq);
663 
664 	if (bf != NULL) {
665 		/*
666 		 * Stop any current dma and put the new frame on the queue.
667 		 * This should never fail since we check above that no frames
668 		 * are still pending on the queue.
669 		 */
670 		if ((! sc->sc_isedma) &&
671 		    (! ath_hal_stoptxdma(ah, sc->sc_bhalq))) {
672 			DPRINTF(sc, ATH_DEBUG_ANY,
673 				"%s: beacon queue %u did not stop?\n",
674 				__func__, sc->sc_bhalq);
675 			/* NB: the HAL still stops DMA, so proceed */
676 		}
677 		ath_hal_puttxbuf(ah, sc->sc_bhalq, bf->bf_daddr);
678 		ath_hal_txstart(ah, sc->sc_bhalq);
679 
680 		sc->sc_stats.ast_be_xmit++;		/* XXX per-vap? */
681 
682 		/*
683 		 * Record local TSF for our last send for use
684 		 * in arbitrating slot collisions.
685 		 */
686 		/* XXX should take a locked ref to iv_bss */
687 		vap->iv_bss->ni_tstamp.tsf = ath_hal_gettsf64(ah);
688 	}
689 }
690 #endif /* IEEE80211_SUPPORT_TDMA */
691