xref: /freebsd/sys/dev/ath/if_ath_tdma.c (revision 641a6cfb86023499caafe26a4d821a0b885cf00b)
1 /*-
2  * Copyright (c) 2002-2009 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer,
10  *    without modification.
11  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13  *    redistribution must be conditioned upon including a substantially
14  *    similar Disclaimer requirement for further binary redistribution.
15  *
16  * NO WARRANTY
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27  * THE POSSIBILITY OF SUCH DAMAGES.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 /*
34  * Driver for the Atheros Wireless LAN controller.
35  *
36  * This software is derived from work of Atsushi Onoe; his contribution
37  * is greatly appreciated.
38  */
39 
40 #include "opt_inet.h"
41 #include "opt_ath.h"
42 /*
43  * This is needed for register operations which are performed
44  * by the driver - eg, calls to ath_hal_gettsf32().
45  *
46  * It's also required for any AH_DEBUG checks in here, eg the
47  * module dependencies.
48  */
49 #include "opt_ah.h"
50 #include "opt_wlan.h"
51 
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/sysctl.h>
55 #include <sys/mbuf.h>
56 #include <sys/malloc.h>
57 #include <sys/lock.h>
58 #include <sys/mutex.h>
59 #include <sys/kernel.h>
60 #include <sys/socket.h>
61 #include <sys/sockio.h>
62 #include <sys/errno.h>
63 #include <sys/callout.h>
64 #include <sys/bus.h>
65 #include <sys/endian.h>
66 #include <sys/kthread.h>
67 #include <sys/taskqueue.h>
68 #include <sys/priv.h>
69 #include <sys/module.h>
70 #include <sys/ktr.h>
71 #include <sys/smp.h>	/* for mp_ncpus */
72 
73 #include <machine/bus.h>
74 
75 #include <net/if.h>
76 #include <net/if_dl.h>
77 #include <net/if_media.h>
78 #include <net/if_types.h>
79 #include <net/if_arp.h>
80 #include <net/ethernet.h>
81 #include <net/if_llc.h>
82 
83 #include <net80211/ieee80211_var.h>
84 #include <net80211/ieee80211_regdomain.h>
85 #ifdef IEEE80211_SUPPORT_SUPERG
86 #include <net80211/ieee80211_superg.h>
87 #endif
88 #ifdef IEEE80211_SUPPORT_TDMA
89 #include <net80211/ieee80211_tdma.h>
90 #endif
91 
92 #include <net/bpf.h>
93 
94 #ifdef INET
95 #include <netinet/in.h>
96 #include <netinet/if_ether.h>
97 #endif
98 
99 #include <dev/ath/if_athvar.h>
100 #include <dev/ath/ath_hal/ah_devid.h>		/* XXX for softled */
101 #include <dev/ath/ath_hal/ah_diagcodes.h>
102 
103 #include <dev/ath/if_ath_debug.h>
104 #include <dev/ath/if_ath_misc.h>
105 #include <dev/ath/if_ath_tsf.h>
106 #include <dev/ath/if_ath_tx.h>
107 #include <dev/ath/if_ath_sysctl.h>
108 #include <dev/ath/if_ath_led.h>
109 #include <dev/ath/if_ath_keycache.h>
110 #include <dev/ath/if_ath_rx.h>
111 #include <dev/ath/if_ath_beacon.h>
112 #include <dev/ath/if_athdfs.h>
113 
114 #ifdef ATH_TX99_DIAG
115 #include <dev/ath/ath_tx99/ath_tx99.h>
116 #endif
117 
118 #ifdef IEEE80211_SUPPORT_TDMA
119 #include <dev/ath/if_ath_tdma.h>
120 
121 static void	ath_tdma_settimers(struct ath_softc *sc, u_int32_t nexttbtt,
122 		    u_int32_t bintval);
123 static void	ath_tdma_bintvalsetup(struct ath_softc *sc,
124 		    const struct ieee80211_tdma_state *tdma);
125 #endif /* IEEE80211_SUPPORT_TDMA */
126 
127 #ifdef IEEE80211_SUPPORT_TDMA
128 static void
129 ath_tdma_settimers(struct ath_softc *sc, u_int32_t nexttbtt, u_int32_t bintval)
130 {
131 	struct ath_hal *ah = sc->sc_ah;
132 	HAL_BEACON_TIMERS bt;
133 
134 	bt.bt_intval = bintval | HAL_BEACON_ENA;
135 	bt.bt_nexttbtt = nexttbtt;
136 	bt.bt_nextdba = (nexttbtt<<3) - sc->sc_tdmadbaprep;
137 	bt.bt_nextswba = (nexttbtt<<3) - sc->sc_tdmaswbaprep;
138 	bt.bt_nextatim = nexttbtt+1;
139 	/* Enables TBTT, DBA, SWBA timers by default */
140 	bt.bt_flags = 0;
141 	ath_hal_beaconsettimers(ah, &bt);
142 }
143 
144 /*
145  * Calculate the beacon interval.  This is periodic in the
146  * superframe for the bss.  We assume each station is configured
147  * identically wrt transmit rate so the guard time we calculate
148  * above will be the same on all stations.  Note we need to
149  * factor in the xmit time because the hardware will schedule
150  * a frame for transmit if the start of the frame is within
151  * the burst time.  When we get hardware that properly kills
152  * frames in the PCU we can reduce/eliminate the guard time.
153  *
154  * Roundup to 1024 is so we have 1 TU buffer in the guard time
155  * to deal with the granularity of the nexttbtt timer.  11n MAC's
156  * with 1us timer granularity should allow us to reduce/eliminate
157  * this.
158  */
159 static void
160 ath_tdma_bintvalsetup(struct ath_softc *sc,
161 	const struct ieee80211_tdma_state *tdma)
162 {
163 	/* copy from vap state (XXX check all vaps have same value?) */
164 	sc->sc_tdmaslotlen = tdma->tdma_slotlen;
165 
166 	sc->sc_tdmabintval = roundup((sc->sc_tdmaslotlen+sc->sc_tdmaguard) *
167 		tdma->tdma_slotcnt, 1024);
168 	sc->sc_tdmabintval >>= 10;		/* TSF -> TU */
169 	if (sc->sc_tdmabintval & 1)
170 		sc->sc_tdmabintval++;
171 
172 	if (tdma->tdma_slot == 0) {
173 		/*
174 		 * Only slot 0 beacons; other slots respond.
175 		 */
176 		sc->sc_imask |= HAL_INT_SWBA;
177 		sc->sc_tdmaswba = 0;		/* beacon immediately */
178 	} else {
179 		/* XXX all vaps must be slot 0 or slot !0 */
180 		sc->sc_imask &= ~HAL_INT_SWBA;
181 	}
182 }
183 
184 /*
185  * Max 802.11 overhead.  This assumes no 4-address frames and
186  * the encapsulation done by ieee80211_encap (llc).  We also
187  * include potential crypto overhead.
188  */
189 #define	IEEE80211_MAXOVERHEAD \
190 	(sizeof(struct ieee80211_qosframe) \
191 	 + sizeof(struct llc) \
192 	 + IEEE80211_ADDR_LEN \
193 	 + IEEE80211_WEP_IVLEN \
194 	 + IEEE80211_WEP_KIDLEN \
195 	 + IEEE80211_WEP_CRCLEN \
196 	 + IEEE80211_WEP_MICLEN \
197 	 + IEEE80211_CRC_LEN)
198 
199 /*
200  * Setup initially for tdma operation.  Start the beacon
201  * timers and enable SWBA if we are slot 0.  Otherwise
202  * we wait for slot 0 to arrive so we can sync up before
203  * starting to transmit.
204  */
205 void
206 ath_tdma_config(struct ath_softc *sc, struct ieee80211vap *vap)
207 {
208 	struct ath_hal *ah = sc->sc_ah;
209 	struct ifnet *ifp = sc->sc_ifp;
210 	struct ieee80211com *ic = ifp->if_l2com;
211 	const struct ieee80211_txparam *tp;
212 	const struct ieee80211_tdma_state *tdma = NULL;
213 	int rix;
214 
215 	if (vap == NULL) {
216 		vap = TAILQ_FIRST(&ic->ic_vaps);   /* XXX */
217 		if (vap == NULL) {
218 			if_printf(ifp, "%s: no vaps?\n", __func__);
219 			return;
220 		}
221 	}
222 	/* XXX should take a locked ref to iv_bss */
223 	tp = vap->iv_bss->ni_txparms;
224 	/*
225 	 * Calculate the guard time for each slot.  This is the
226 	 * time to send a maximal-size frame according to the
227 	 * fixed/lowest transmit rate.  Note that the interface
228 	 * mtu does not include the 802.11 overhead so we must
229 	 * tack that on (ath_hal_computetxtime includes the
230 	 * preamble and plcp in it's calculation).
231 	 */
232 	tdma = vap->iv_tdma;
233 	if (tp->ucastrate != IEEE80211_FIXED_RATE_NONE)
234 		rix = ath_tx_findrix(sc, tp->ucastrate);
235 	else
236 		rix = ath_tx_findrix(sc, tp->mcastrate);
237 	/* XXX short preamble assumed */
238 	sc->sc_tdmaguard = ath_hal_computetxtime(ah, sc->sc_currates,
239 		ifp->if_mtu + IEEE80211_MAXOVERHEAD, rix, AH_TRUE);
240 
241 	ath_hal_intrset(ah, 0);
242 
243 	ath_beaconq_config(sc);			/* setup h/w beacon q */
244 	if (sc->sc_setcca)
245 		ath_hal_setcca(ah, AH_FALSE);	/* disable CCA */
246 	ath_tdma_bintvalsetup(sc, tdma);	/* calculate beacon interval */
247 	ath_tdma_settimers(sc, sc->sc_tdmabintval,
248 		sc->sc_tdmabintval | HAL_BEACON_RESET_TSF);
249 	sc->sc_syncbeacon = 0;
250 
251 	sc->sc_avgtsfdeltap = TDMA_DUMMY_MARKER;
252 	sc->sc_avgtsfdeltam = TDMA_DUMMY_MARKER;
253 
254 	ath_hal_intrset(ah, sc->sc_imask);
255 
256 	DPRINTF(sc, ATH_DEBUG_TDMA, "%s: slot %u len %uus cnt %u "
257 	    "bsched %u guard %uus bintval %u TU dba prep %u\n", __func__,
258 	    tdma->tdma_slot, tdma->tdma_slotlen, tdma->tdma_slotcnt,
259 	    tdma->tdma_bintval, sc->sc_tdmaguard, sc->sc_tdmabintval,
260 	    sc->sc_tdmadbaprep);
261 }
262 
263 /*
264  * Update tdma operation.  Called from the 802.11 layer
265  * when a beacon is received from the TDMA station operating
266  * in the slot immediately preceding us in the bss.  Use
267  * the rx timestamp for the beacon frame to update our
268  * beacon timers so we follow their schedule.  Note that
269  * by using the rx timestamp we implicitly include the
270  * propagation delay in our schedule.
271  */
272 void
273 ath_tdma_update(struct ieee80211_node *ni,
274 	const struct ieee80211_tdma_param *tdma, int changed)
275 {
276 #define	TSF_TO_TU(_h,_l) \
277 	((((u_int32_t)(_h)) << 22) | (((u_int32_t)(_l)) >> 10))
278 #define	TU_TO_TSF(_tu)	(((u_int64_t)(_tu)) << 10)
279 	struct ieee80211vap *vap = ni->ni_vap;
280 	struct ieee80211com *ic = ni->ni_ic;
281 	struct ath_softc *sc = ic->ic_ifp->if_softc;
282 	struct ath_hal *ah = sc->sc_ah;
283 	const HAL_RATE_TABLE *rt = sc->sc_currates;
284 	u_int64_t tsf, rstamp, nextslot, nexttbtt;
285 	u_int32_t txtime, nextslottu;
286 	int32_t tudelta, tsfdelta;
287 	const struct ath_rx_status *rs;
288 	int rix;
289 
290 	sc->sc_stats.ast_tdma_update++;
291 
292 	/*
293 	 * Check for and adopt configuration changes.
294 	 */
295 	if (changed != 0) {
296 		const struct ieee80211_tdma_state *ts = vap->iv_tdma;
297 
298 		ath_tdma_bintvalsetup(sc, ts);
299 		if (changed & TDMA_UPDATE_SLOTLEN)
300 			ath_wme_update(ic);
301 
302 		DPRINTF(sc, ATH_DEBUG_TDMA,
303 		    "%s: adopt slot %u slotcnt %u slotlen %u us "
304 		    "bintval %u TU\n", __func__,
305 		    ts->tdma_slot, ts->tdma_slotcnt, ts->tdma_slotlen,
306 		    sc->sc_tdmabintval);
307 
308 		/* XXX right? */
309 		ath_hal_intrset(ah, sc->sc_imask);
310 		/* NB: beacon timers programmed below */
311 	}
312 
313 	/* extend rx timestamp to 64 bits */
314 	rs = sc->sc_lastrs;
315 	tsf = ath_hal_gettsf64(ah);
316 	rstamp = ath_extend_tsf(sc, rs->rs_tstamp, tsf);
317 	/*
318 	 * The rx timestamp is set by the hardware on completing
319 	 * reception (at the point where the rx descriptor is DMA'd
320 	 * to the host).  To find the start of our next slot we
321 	 * must adjust this time by the time required to send
322 	 * the packet just received.
323 	 */
324 	rix = rt->rateCodeToIndex[rs->rs_rate];
325 	txtime = ath_hal_computetxtime(ah, rt, rs->rs_datalen, rix,
326 	    rt->info[rix].shortPreamble);
327 	/* NB: << 9 is to cvt to TU and /2 */
328 	nextslot = (rstamp - txtime) + (sc->sc_tdmabintval << 9);
329 	nextslottu = TSF_TO_TU(nextslot>>32, nextslot) & HAL_BEACON_PERIOD;
330 
331 	/*
332 	 * Retrieve the hardware NextTBTT in usecs
333 	 * and calculate the difference between what the
334 	 * other station thinks and what we have programmed.  This
335 	 * lets us figure how to adjust our timers to match.  The
336 	 * adjustments are done by pulling the TSF forward and possibly
337 	 * rewriting the beacon timers.
338 	 */
339 	nexttbtt = ath_hal_getnexttbtt(ah);
340 	tsfdelta = (int32_t)((nextslot % TU_TO_TSF(HAL_BEACON_PERIOD + 1)) - nexttbtt);
341 
342 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
343 	    "tsfdelta %d avg +%d/-%d\n", tsfdelta,
344 	    TDMA_AVG(sc->sc_avgtsfdeltap), TDMA_AVG(sc->sc_avgtsfdeltam));
345 
346 	if (tsfdelta < 0) {
347 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, 0);
348 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, -tsfdelta);
349 		tsfdelta = -tsfdelta % 1024;
350 		nextslottu++;
351 	} else if (tsfdelta > 0) {
352 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, tsfdelta);
353 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, 0);
354 		tsfdelta = 1024 - (tsfdelta % 1024);
355 		nextslottu++;
356 	} else {
357 		TDMA_SAMPLE(sc->sc_avgtsfdeltap, 0);
358 		TDMA_SAMPLE(sc->sc_avgtsfdeltam, 0);
359 	}
360 	tudelta = nextslottu - TSF_TO_TU(nexttbtt >> 32, nexttbtt);
361 
362 	/*
363 	 * Copy sender's timetstamp into tdma ie so they can
364 	 * calculate roundtrip time.  We submit a beacon frame
365 	 * below after any timer adjustment.  The frame goes out
366 	 * at the next TBTT so the sender can calculate the
367 	 * roundtrip by inspecting the tdma ie in our beacon frame.
368 	 *
369 	 * NB: This tstamp is subtlely preserved when
370 	 *     IEEE80211_BEACON_TDMA is marked (e.g. when the
371 	 *     slot position changes) because ieee80211_add_tdma
372 	 *     skips over the data.
373 	 */
374 	memcpy(ATH_VAP(vap)->av_boff.bo_tdma +
375 		__offsetof(struct ieee80211_tdma_param, tdma_tstamp),
376 		&ni->ni_tstamp.data, 8);
377 #if 0
378 	DPRINTF(sc, ATH_DEBUG_TDMA_TIMER,
379 	    "tsf %llu nextslot %llu (%d, %d) nextslottu %u nexttbtt %llu (%d)\n",
380 	    (unsigned long long) tsf, (unsigned long long) nextslot,
381 	    (int)(nextslot - tsf), tsfdelta, nextslottu, nexttbtt, tudelta);
382 #endif
383 	/*
384 	 * Adjust the beacon timers only when pulling them forward
385 	 * or when going back by less than the beacon interval.
386 	 * Negative jumps larger than the beacon interval seem to
387 	 * cause the timers to stop and generally cause instability.
388 	 * This basically filters out jumps due to missed beacons.
389 	 */
390 	if (tudelta != 0 && (tudelta > 0 || -tudelta < sc->sc_tdmabintval)) {
391 		ath_tdma_settimers(sc, nextslottu, sc->sc_tdmabintval);
392 		sc->sc_stats.ast_tdma_timers++;
393 	}
394 	if (tsfdelta > 0) {
395 		ath_hal_adjusttsf(ah, tsfdelta);
396 		sc->sc_stats.ast_tdma_tsf++;
397 	}
398 	ath_tdma_beacon_send(sc, vap);		/* prepare response */
399 #undef TU_TO_TSF
400 #undef TSF_TO_TU
401 }
402 
403 /*
404  * Transmit a beacon frame at SWBA.  Dynamic updates
405  * to the frame contents are done as needed.
406  */
407 void
408 ath_tdma_beacon_send(struct ath_softc *sc, struct ieee80211vap *vap)
409 {
410 	struct ath_hal *ah = sc->sc_ah;
411 	struct ath_buf *bf;
412 	int otherant;
413 
414 	/*
415 	 * Check if the previous beacon has gone out.  If
416 	 * not don't try to post another, skip this period
417 	 * and wait for the next.  Missed beacons indicate
418 	 * a problem and should not occur.  If we miss too
419 	 * many consecutive beacons reset the device.
420 	 */
421 	if (ath_hal_numtxpending(ah, sc->sc_bhalq) != 0) {
422 		sc->sc_bmisscount++;
423 		DPRINTF(sc, ATH_DEBUG_BEACON,
424 			"%s: missed %u consecutive beacons\n",
425 			__func__, sc->sc_bmisscount);
426 		if (sc->sc_bmisscount >= ath_bstuck_threshold)
427 			taskqueue_enqueue(sc->sc_tq, &sc->sc_bstucktask);
428 		return;
429 	}
430 	if (sc->sc_bmisscount != 0) {
431 		DPRINTF(sc, ATH_DEBUG_BEACON,
432 			"%s: resume beacon xmit after %u misses\n",
433 			__func__, sc->sc_bmisscount);
434 		sc->sc_bmisscount = 0;
435 	}
436 
437 	/*
438 	 * Check recent per-antenna transmit statistics and flip
439 	 * the default antenna if noticeably more frames went out
440 	 * on the non-default antenna.
441 	 * XXX assumes 2 anntenae
442 	 */
443 	if (!sc->sc_diversity) {
444 		otherant = sc->sc_defant & 1 ? 2 : 1;
445 		if (sc->sc_ant_tx[otherant] > sc->sc_ant_tx[sc->sc_defant] + 2)
446 			ath_setdefantenna(sc, otherant);
447 		sc->sc_ant_tx[1] = sc->sc_ant_tx[2] = 0;
448 	}
449 
450 	bf = ath_beacon_generate(sc, vap);
451 	if (bf != NULL) {
452 		/*
453 		 * Stop any current dma and put the new frame on the queue.
454 		 * This should never fail since we check above that no frames
455 		 * are still pending on the queue.
456 		 */
457 		if (!ath_hal_stoptxdma(ah, sc->sc_bhalq)) {
458 			DPRINTF(sc, ATH_DEBUG_ANY,
459 				"%s: beacon queue %u did not stop?\n",
460 				__func__, sc->sc_bhalq);
461 			/* NB: the HAL still stops DMA, so proceed */
462 		}
463 		ath_hal_puttxbuf(ah, sc->sc_bhalq, bf->bf_daddr);
464 		ath_hal_txstart(ah, sc->sc_bhalq);
465 
466 		sc->sc_stats.ast_be_xmit++;		/* XXX per-vap? */
467 
468 		/*
469 		 * Record local TSF for our last send for use
470 		 * in arbitrating slot collisions.
471 		 */
472 		/* XXX should take a locked ref to iv_bss */
473 		vap->iv_bss->ni_tstamp.tsf = ath_hal_gettsf64(ah);
474 	}
475 }
476 #endif /* IEEE80211_SUPPORT_TDMA */
477