xref: /freebsd/sys/dev/ath/if_ath_tx_ht.c (revision ec65e4f8d0654361df5e97d4de3518edebf76b46)
1 /*-
2  * Copyright (c) 2011 Adrian Chadd, Xenion Pty Ltd.
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 #include "opt_inet.h"
34 #include "opt_ath.h"
35 #include "opt_wlan.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sysctl.h>
40 #include <sys/mbuf.h>
41 #include <sys/malloc.h>
42 #include <sys/lock.h>
43 #include <sys/mutex.h>
44 #include <sys/kernel.h>
45 #include <sys/socket.h>
46 #include <sys/sockio.h>
47 #include <sys/errno.h>
48 #include <sys/callout.h>
49 #include <sys/bus.h>
50 #include <sys/endian.h>
51 #include <sys/kthread.h>
52 #include <sys/taskqueue.h>
53 #include <sys/priv.h>
54 
55 #include <machine/bus.h>
56 
57 #include <net/if.h>
58 #include <net/if_dl.h>
59 #include <net/if_media.h>
60 #include <net/if_types.h>
61 #include <net/if_arp.h>
62 #include <net/ethernet.h>
63 #include <net/if_llc.h>
64 
65 #include <net80211/ieee80211_var.h>
66 #include <net80211/ieee80211_regdomain.h>
67 #ifdef IEEE80211_SUPPORT_SUPERG
68 #include <net80211/ieee80211_superg.h>
69 #endif
70 #ifdef IEEE80211_SUPPORT_TDMA
71 #include <net80211/ieee80211_tdma.h>
72 #endif
73 
74 #include <net/bpf.h>
75 
76 #ifdef INET
77 #include <netinet/in.h>
78 #include <netinet/if_ether.h>
79 #endif
80 
81 #include <dev/ath/if_athvar.h>
82 #include <dev/ath/ath_hal/ah_devid.h>		/* XXX for softled */
83 #include <dev/ath/ath_hal/ah_diagcodes.h>
84 
85 #ifdef ATH_TX99_DIAG
86 #include <dev/ath/ath_tx99/ath_tx99.h>
87 #endif
88 
89 #include <dev/ath/if_ath_tx.h>		/* XXX for some support functions */
90 #include <dev/ath/if_ath_tx_ht.h>
91 #include <dev/ath/if_athrate.h>
92 #include <dev/ath/if_ath_debug.h>
93 
94 /*
95  * XXX net80211?
96  */
97 #define	IEEE80211_AMPDU_SUBFRAME_DEFAULT		32
98 
99 #define	ATH_AGGR_DELIM_SZ	4	/* delimiter size */
100 #define	ATH_AGGR_MINPLEN	256	/* in bytes, minimum packet length */
101 /* number of delimiters for encryption padding */
102 #define	ATH_AGGR_ENCRYPTDELIM	10
103 
104 /*
105  * returns delimiter padding required given the packet length
106  */
107 #define	ATH_AGGR_GET_NDELIM(_len)					\
108 	    (((((_len) + ATH_AGGR_DELIM_SZ) < ATH_AGGR_MINPLEN) ?	\
109 	    (ATH_AGGR_MINPLEN - (_len) - ATH_AGGR_DELIM_SZ) : 0) >> 2)
110 
111 #define	PADBYTES(_len)		((4 - ((_len) % 4)) % 4)
112 
113 int ath_max_4ms_framelen[4][32] = {
114 	[MCS_HT20] = {
115 		3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
116 		6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
117 		9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
118 		12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
119 	},
120 	[MCS_HT20_SGI] = {
121 		3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
122 		7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
123 		10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
124 		14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
125 	},
126 	[MCS_HT40] = {
127 		6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
128 		13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
129 		20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
130 		26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
131 	},
132 	[MCS_HT40_SGI] = {
133 		7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
134 		14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
135 		22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
136 		29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
137 	}
138 };
139 
140 /*
141  * XXX should be in net80211
142  */
143 static int ieee80211_mpdudensity_map[] = {
144 	0,		/* IEEE80211_HTCAP_MPDUDENSITY_NA */
145 	25,		/* IEEE80211_HTCAP_MPDUDENSITY_025 */
146 	50,		/* IEEE80211_HTCAP_MPDUDENSITY_05 */
147 	100,		/* IEEE80211_HTCAP_MPDUDENSITY_1 */
148 	200,		/* IEEE80211_HTCAP_MPDUDENSITY_2 */
149 	400,		/* IEEE80211_HTCAP_MPDUDENSITY_4 */
150 	800,		/* IEEE80211_HTCAP_MPDUDENSITY_8 */
151 	1600,		/* IEEE80211_HTCAP_MPDUDENSITY_16 */
152 };
153 
154 /*
155  * XXX should be in the HAL/net80211 ?
156  */
157 #define	BITS_PER_BYTE		8
158 #define	OFDM_PLCP_BITS		22
159 #define	HT_RC_2_MCS(_rc)	((_rc) & 0x7f)
160 #define	HT_RC_2_STREAMS(_rc)	((((_rc) & 0x78) >> 3) + 1)
161 #define	L_STF			8
162 #define	L_LTF			8
163 #define	L_SIG			4
164 #define	HT_SIG			8
165 #define	HT_STF			4
166 #define	HT_LTF(_ns)		(4 * (_ns))
167 #define	SYMBOL_TIME(_ns)	((_ns) << 2)		// ns * 4 us
168 #define	SYMBOL_TIME_HALFGI(_ns)	(((_ns) * 18 + 4) / 5)	// ns * 3.6 us
169 #define	NUM_SYMBOLS_PER_USEC(_usec)	(_usec >> 2)
170 #define	NUM_SYMBOLS_PER_USEC_HALFGI(_usec)	(((_usec*5)-4)/18)
171 #define	IS_HT_RATE(_rate)	((_rate) & 0x80)
172 
173 const uint32_t bits_per_symbol[][2] = {
174     /* 20MHz 40MHz */
175     {    26,   54 },     //  0: BPSK
176     {    52,  108 },     //  1: QPSK 1/2
177     {    78,  162 },     //  2: QPSK 3/4
178     {   104,  216 },     //  3: 16-QAM 1/2
179     {   156,  324 },     //  4: 16-QAM 3/4
180     {   208,  432 },     //  5: 64-QAM 2/3
181     {   234,  486 },     //  6: 64-QAM 3/4
182     {   260,  540 },     //  7: 64-QAM 5/6
183     {    52,  108 },     //  8: BPSK
184     {   104,  216 },     //  9: QPSK 1/2
185     {   156,  324 },     // 10: QPSK 3/4
186     {   208,  432 },     // 11: 16-QAM 1/2
187     {   312,  648 },     // 12: 16-QAM 3/4
188     {   416,  864 },     // 13: 64-QAM 2/3
189     {   468,  972 },     // 14: 64-QAM 3/4
190     {   520, 1080 },     // 15: 64-QAM 5/6
191     {    78,  162 },     // 16: BPSK
192     {   156,  324 },     // 17: QPSK 1/2
193     {   234,  486 },     // 18: QPSK 3/4
194     {   312,  648 },     // 19: 16-QAM 1/2
195     {   468,  972 },     // 20: 16-QAM 3/4
196     {   624, 1296 },     // 21: 64-QAM 2/3
197     {   702, 1458 },     // 22: 64-QAM 3/4
198     {   780, 1620 },     // 23: 64-QAM 5/6
199     {   104,  216 },     // 24: BPSK
200     {   208,  432 },     // 25: QPSK 1/2
201     {   312,  648 },     // 26: QPSK 3/4
202     {   416,  864 },     // 27: 16-QAM 1/2
203     {   624, 1296 },     // 28: 16-QAM 3/4
204     {   832, 1728 },     // 29: 64-QAM 2/3
205     {   936, 1944 },     // 30: 64-QAM 3/4
206     {  1040, 2160 },     // 31: 64-QAM 5/6
207 };
208 
209 /*
210  * Fill in the rate array information based on the current
211  * node configuration and the choices made by the rate
212  * selection code and ath_buf setup code.
213  *
214  * Later on, this may end up also being made by the
215  * rate control code, but for now it can live here.
216  *
217  * This needs to be called just before the packet is
218  * queued to the software queue or hardware queue,
219  * so all of the needed fields in bf_state are setup.
220  */
221 void
222 ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
223 {
224 	struct ieee80211_node *ni = bf->bf_node;
225 	struct ieee80211com *ic = ni->ni_ic;
226 	const HAL_RATE_TABLE *rt = sc->sc_currates;
227 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
228 	uint8_t rate;
229 	int i;
230 	int do_ldpc;
231 	int do_stbc;
232 
233 	/*
234 	 * We only do LDPC if the rate is 11n, both we and the
235 	 * receiver support LDPC and it's enabled.
236 	 *
237 	 * It's a global flag, not a per-try flag, so we clear
238 	 * it if any of the rate entries aren't 11n.
239 	 */
240 	do_ldpc = 0;
241 	if ((ni->ni_vap->iv_htcaps & IEEE80211_HTCAP_LDPC) &&
242 	    (ni->ni_htcap & IEEE80211_HTCAP_LDPC))
243 		do_ldpc = 1;
244 	do_stbc = 0;
245 
246 	for (i = 0; i < ATH_RC_NUM; i++) {
247 		rc[i].flags = 0;
248 		if (rc[i].tries == 0)
249 			continue;
250 
251 		rate = rt->info[rc[i].rix].rateCode;
252 
253 		/*
254 		 * Only enable short preamble for legacy rates
255 		 */
256 		if ((! IS_HT_RATE(rate)) && bf->bf_state.bfs_shpream)
257 			rate |= rt->info[rc[i].rix].shortPreamble;
258 
259 		/*
260 		 * Save this, used by the TX and completion code
261 		 */
262 		rc[i].ratecode = rate;
263 
264 		if (bf->bf_state.bfs_txflags &
265 		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
266 			rc[i].flags |= ATH_RC_RTSCTS_FLAG;
267 
268 		/*
269 		 * If we can't do LDPC, don't.
270 		 */
271 		if (! IS_HT_RATE(rate))
272 			do_ldpc = 0;
273 
274 		/* Only enable shortgi, 2040, dual-stream if HT is set */
275 		if (IS_HT_RATE(rate)) {
276 			rc[i].flags |= ATH_RC_HT_FLAG;
277 
278 			if (ni->ni_chw == 40)
279 				rc[i].flags |= ATH_RC_CW40_FLAG;
280 
281 			if (ni->ni_chw == 40 &&
282 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
283 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
284 				rc[i].flags |= ATH_RC_SGI_FLAG;
285 
286 			if (ni->ni_chw == 20 &&
287 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
288 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
289 				rc[i].flags |= ATH_RC_SGI_FLAG;
290 
291 			/*
292 			 * If we have STBC TX enabled and the receiver
293 			 * can receive (at least) 1 stream STBC, AND it's
294 			 * MCS 0-7, AND we have at least two chains enabled,
295 			 * enable STBC.
296 			 *
297 			 * XXX TODO: .. and the rate is an 11n rate?
298 			 */
299 			if (ic->ic_htcaps & IEEE80211_HTCAP_TXSTBC &&
300 			    ni->ni_vap->iv_flags_ht & IEEE80211_FHT_STBC_TX &&
301 			    ni->ni_htcap & IEEE80211_HTCAP_RXSTBC_1STREAM &&
302 			    (sc->sc_cur_txchainmask > 1) &&
303 			    HT_RC_2_STREAMS(rate) == 1) {
304 				rc[i].flags |= ATH_RC_STBC_FLAG;
305 				do_stbc = 1;
306 			}
307 
308 			/*
309 			 * Dual / Triple stream rate?
310 			 */
311 			if (HT_RC_2_STREAMS(rate) == 2)
312 				rc[i].flags |= ATH_RC_DS_FLAG;
313 			else if (HT_RC_2_STREAMS(rate) == 3)
314 				rc[i].flags |= ATH_RC_TS_FLAG;
315 		}
316 
317 		/*
318 		 * Calculate the maximum TX power cap for the current
319 		 * node.
320 		 */
321 		rc[i].tx_power_cap = ieee80211_get_node_txpower(ni);
322 
323 		/*
324 		 * Calculate the maximum 4ms frame length based
325 		 * on the MCS rate, SGI and channel width flags.
326 		 */
327 		if ((rc[i].flags & ATH_RC_HT_FLAG) &&
328 		    (HT_RC_2_MCS(rate) < 32)) {
329 			int j;
330 			if (rc[i].flags & ATH_RC_CW40_FLAG) {
331 				if (rc[i].flags & ATH_RC_SGI_FLAG)
332 					j = MCS_HT40_SGI;
333 				else
334 					j = MCS_HT40;
335 			} else {
336 				if (rc[i].flags & ATH_RC_SGI_FLAG)
337 					j = MCS_HT20_SGI;
338 				else
339 					j = MCS_HT20;
340 			}
341 			rc[i].max4msframelen =
342 			    ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
343 		} else
344 			rc[i].max4msframelen = 0;
345 		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
346 		    "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
347 		    __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
348 	}
349 
350 	/*
351 	 * LDPC is a global flag, so ...
352 	 */
353 	if (do_ldpc) {
354 		bf->bf_state.bfs_txflags |= HAL_TXDESC_LDPC;
355 		sc->sc_stats.ast_tx_ldpc++;
356 	}
357 
358 	if (do_stbc) {
359 		sc->sc_stats.ast_tx_stbc++;
360 	}
361 }
362 
363 /*
364  * Return the number of delimiters to be added to
365  * meet the minimum required mpdudensity.
366  *
367  * Caller should make sure that the rate is HT.
368  *
369  * TODO: is this delimiter calculation supposed to be the
370  * total frame length, the hdr length, the data length (including
371  * delimiters, padding, CRC, etc) or ?
372  *
373  * TODO: this should ensure that the rate control information
374  * HAS been setup for the first rate.
375  *
376  * TODO: ensure this is only called for MCS rates.
377  *
378  * TODO: enforce MCS < 31
379  */
380 static int
381 ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
382     uint16_t pktlen)
383 {
384 	const HAL_RATE_TABLE *rt = sc->sc_currates;
385 	struct ieee80211_node *ni = first_bf->bf_node;
386 	struct ieee80211vap *vap = ni->ni_vap;
387 	int ndelim, mindelim = 0;
388 	int mpdudensity;	 /* in 1/100'th of a microsecond */
389 	uint8_t rc, rix, flags;
390 	int width, half_gi;
391 	uint32_t nsymbits, nsymbols;
392 	uint16_t minlen;
393 
394 	/*
395 	 * vap->iv_ampdu_density is a value, rather than the actual
396 	 * density.
397 	 */
398 	if (vap->iv_ampdu_density > IEEE80211_HTCAP_MPDUDENSITY_16)
399 		mpdudensity = 1600;		/* maximum density */
400 	else
401 		mpdudensity = ieee80211_mpdudensity_map[vap->iv_ampdu_density];
402 
403 	/* Select standard number of delimiters based on frame length */
404 	ndelim = ATH_AGGR_GET_NDELIM(pktlen);
405 
406 	/*
407 	 * If encryption is enabled, add extra delimiters to let the
408 	 * crypto hardware catch up. This could be tuned per-MAC and
409 	 * per-rate, but for now we'll simply assume encryption is
410 	 * always enabled.
411 	 *
412 	 * Also note that the Atheros reference driver inserts two
413 	 * delimiters by default for pre-AR9380 peers.  This will
414 	 * include "that" required delimiter.
415 	 */
416 	ndelim += ATH_AGGR_ENCRYPTDELIM;
417 
418 	/*
419 	 * For AR9380, there's a minimum number of delimeters
420 	 * required when doing RTS.
421 	 *
422 	 * XXX TODO: this is only needed if (a) RTS/CTS is enabled, and
423 	 * XXX (b) this is the first sub-frame in the aggregate.
424 	 */
425 	if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
426 	    && ndelim < AH_FIRST_DESC_NDELIMS)
427 		ndelim = AH_FIRST_DESC_NDELIMS;
428 
429 	/*
430 	 * If sc_delim_min_pad is non-zero, enforce it as the minimum
431 	 * pad delimiter count.
432 	 */
433 	if (sc->sc_delim_min_pad != 0)
434 		ndelim = MAX(ndelim, sc->sc_delim_min_pad);
435 
436 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
437 	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
438 	    __func__, pktlen, ndelim, mpdudensity);
439 
440 	/*
441 	 * If the MPDU density is 0, we can return here.
442 	 * Otherwise, we need to convert the desired mpdudensity
443 	 * into a byte length, based on the rate in the subframe.
444 	 */
445 	if (mpdudensity == 0)
446 		return ndelim;
447 
448 	/*
449 	 * Convert desired mpdu density from microeconds to bytes based
450 	 * on highest rate in rate series (i.e. first rate) to determine
451 	 * required minimum length for subframe. Take into account
452 	 * whether high rate is 20 or 40Mhz and half or full GI.
453 	 */
454 	rix = first_bf->bf_state.bfs_rc[0].rix;
455 	rc = rt->info[rix].rateCode;
456 	flags = first_bf->bf_state.bfs_rc[0].flags;
457 	width = !! (flags & ATH_RC_CW40_FLAG);
458 	half_gi = !! (flags & ATH_RC_SGI_FLAG);
459 
460 	/*
461 	 * mpdudensity is in 1/100th of a usec, so divide by 100
462 	 */
463 	if (half_gi)
464 		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
465 	else
466 		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
467 	nsymbols /= 100;
468 
469 	if (nsymbols == 0)
470 		nsymbols = 1;
471 
472 	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
473 	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
474 
475 	/*
476 	 * Min length is the minimum frame length for the
477 	 * required MPDU density.
478 	 */
479 	if (pktlen < minlen) {
480 		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
481 		ndelim = MAX(mindelim, ndelim);
482 	}
483 
484 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
485 	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
486 	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
487 
488 	return ndelim;
489 }
490 
491 /*
492  * Fetch the aggregation limit.
493  *
494  * It's the lowest of the four rate series 4ms frame length.
495  */
496 static int
497 ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
498 {
499 	int amin = ATH_AGGR_MAXSIZE;
500 	int i;
501 
502 	if (sc->sc_aggr_limit > 0 && sc->sc_aggr_limit < ATH_AGGR_MAXSIZE)
503 		amin = sc->sc_aggr_limit;
504 
505 	for (i = 0; i < ATH_RC_NUM; i++) {
506 		if (bf->bf_state.bfs_rc[i].tries == 0)
507 			continue;
508 		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
509 	}
510 
511 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
512 	    __func__, amin);
513 
514 	return amin;
515 }
516 
517 /*
518  * Setup a 11n rate series structure
519  *
520  * This should be called for both legacy and MCS rates.
521  *
522  * This uses the rate series stuf from ath_tx_rate_fill_rcflags().
523  *
524  * It, along with ath_buf_set_rate, must be called -after- a burst
525  * or aggregate is setup.
526  */
527 static void
528 ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
529     struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
530 {
531 	struct ieee80211com *ic = ni->ni_ic;
532 	struct ath_hal *ah = sc->sc_ah;
533 	HAL_BOOL shortPreamble = AH_FALSE;
534 	const HAL_RATE_TABLE *rt = sc->sc_currates;
535 	int i;
536 	int pktlen;
537 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
538 
539 	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
540 	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
541 		shortPreamble = AH_TRUE;
542 
543 	/*
544 	 * If this is the first frame in an aggregate series,
545 	 * use the aggregate length.
546 	 */
547 	if (bf->bf_state.bfs_aggr)
548 		pktlen = bf->bf_state.bfs_al;
549 	else
550 		pktlen = bf->bf_state.bfs_pktlen;
551 
552 	/*
553 	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
554 	 * XXX fields.
555 	 */
556 	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
557 	for (i = 0; i < ATH_RC_NUM;  i++) {
558 		/* Only set flags for actual TX attempts */
559 		if (rc[i].tries == 0)
560 			continue;
561 
562 		series[i].Tries = rc[i].tries;
563 
564 		/*
565 		 * XXX TODO: When the NIC is capable of three stream TX,
566 		 * transmit 1/2 stream rates on two streams.
567 		 *
568 		 * This reduces the power consumption of the NIC and
569 		 * keeps it within the PCIe slot power limits.
570 		 */
571 		series[i].ChSel = sc->sc_cur_txchainmask;
572 
573 		/*
574 		 * Setup rate and TX power cap for this series.
575 		 */
576 		series[i].Rate = rt->info[rc[i].rix].rateCode;
577 		series[i].RateIndex = rc[i].rix;
578 		series[i].tx_power_cap = rc[i].tx_power_cap;
579 
580 		/*
581 		 * Enable RTS/CTS as appropriate.
582 		 */
583 		if (rc[i].flags & ATH_RC_RTSCTS_FLAG)
584 			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
585 
586 		/*
587 		 * 11n rate? Update 11n flags.
588 		 */
589 		if (rc[i].flags & ATH_RC_HT_FLAG) {
590 			if (rc[i].flags & ATH_RC_CW40_FLAG)
591 				series[i].RateFlags |= HAL_RATESERIES_2040;
592 
593 			if (rc[i].flags & ATH_RC_SGI_FLAG)
594 				series[i].RateFlags |= HAL_RATESERIES_HALFGI;
595 
596 			if (rc[i].flags & ATH_RC_STBC_FLAG)
597 				series[i].RateFlags |= HAL_RATESERIES_STBC;
598 		}
599 
600 		/*
601 		 * TODO: If we're all doing 11n rates then we can set LDPC.
602 		 * If we've been asked to /do/ LDPC but we are handed a
603 		 * legacy rate, then we should complain.  Loudly.
604 		 */
605 
606 		/*
607 		 * PktDuration doesn't include slot, ACK, RTS, etc timing -
608 		 * it's just the packet duration
609 		 */
610 		if (rc[i].flags & ATH_RC_HT_FLAG) {
611 			series[i].PktDuration =
612 			    ath_computedur_ht(pktlen
613 				, series[i].Rate
614 				, HT_RC_2_STREAMS(series[i].Rate)
615 				, series[i].RateFlags & HAL_RATESERIES_2040
616 				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
617 		} else {
618 			if (shortPreamble)
619 				series[i].Rate |=
620 				    rt->info[rc[i].rix].shortPreamble;
621 			series[i].PktDuration = ath_hal_computetxtime(ah,
622 			    rt, pktlen, rc[i].rix, shortPreamble);
623 		}
624 	}
625 }
626 
627 #ifdef	ATH_DEBUG
628 static void
629 ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
630 {
631 	int i;
632 	for (i = 0; i < ATH_RC_NUM; i++) {
633 		device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
634 		    "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
635 		    i,
636 		    series[i].Rate,
637 		    series[i].Tries,
638 		    series[i].PktDuration,
639 		    series[i].ChSel,
640 		    series[i].tx_power_cap,
641 		    series[i].RateFlags);
642 	}
643 }
644 #endif
645 
646 /*
647  * Setup the 11n rate scenario and burst duration for the given TX descriptor
648  * list.
649  *
650  * This isn't useful for sending beacon frames, which has different needs
651  * wrt what's passed into the rate scenario function.
652  */
653 void
654 ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
655     struct ath_buf *bf)
656 {
657 	HAL_11N_RATE_SERIES series[4];
658 	struct ath_desc *ds = bf->bf_desc;
659 	struct ath_hal *ah = sc->sc_ah;
660 	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
661 	int ctsrate = bf->bf_state.bfs_ctsrate;
662 	int flags = bf->bf_state.bfs_txflags;
663 
664 	/* Setup rate scenario */
665 	memset(&series, 0, sizeof(series));
666 
667 	ath_rateseries_setup(sc, ni, bf, series);
668 
669 #ifdef	ATH_DEBUG
670 	if (sc->sc_debug & ATH_DEBUG_XMIT)
671 		ath_rateseries_print(sc, series);
672 #endif
673 
674 	/* Set rate scenario */
675 	/*
676 	 * Note: Don't allow hardware to override the duration on
677 	 * ps-poll packets.
678 	 */
679 	ath_hal_set11nratescenario(ah, ds,
680 	    !is_pspoll,	/* whether to override the duration or not */
681 	    ctsrate,	/* rts/cts rate */
682 	    series,	/* 11n rate series */
683 	    4,		/* number of series */
684 	    flags);
685 
686 	/* Set burst duration */
687 	/*
688 	 * This is only required when doing 11n burst, not aggregation
689 	 * ie, if there's a second frame in a RIFS or A-MPDU burst
690 	 * w/ >1 A-MPDU frame bursting back to back.
691 	 * Normal A-MPDU doesn't do bursting -between- aggregates.
692 	 *
693 	 * .. and it's highly likely this won't ever be implemented
694 	 */
695 	//ath_hal_set11nburstduration(ah, ds, 8192);
696 }
697 
698 /*
699  * Form an aggregate packet list.
700  *
701  * This function enforces the aggregate restrictions/requirements.
702  *
703  * These are:
704  *
705  * + The aggregate size maximum (64k for AR9160 and later, 8K for
706  *   AR5416 when doing RTS frame protection.)
707  * + Maximum number of sub-frames for an aggregate
708  * + The aggregate delimiter size, giving MACs time to do whatever is
709  *   needed before each frame
710  * + Enforce the BAW limit
711  *
712  * Each descriptor queued should have the DMA setup.
713  * The rate series, descriptor setup, linking, etc is all done
714  * externally. This routine simply chains them together.
715  * ath_tx_setds_11n() will take care of configuring the per-
716  * descriptor setup, and ath_buf_set_rate() will configure the
717  * rate control.
718  *
719  * The TID lock is required for the entirety of this function.
720  *
721  * If some code in another thread adds to the head of this
722  * list, very strange behaviour will occur. Since retransmission is the
723  * only reason this will occur, and this routine is designed to be called
724  * from within the scheduler task, it won't ever clash with the completion
725  * task.
726  *
727  * So if you want to call this from an upper layer context (eg, to direct-
728  * dispatch aggregate frames to the hardware), please keep this in mind.
729  */
730 ATH_AGGR_STATUS
731 ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
732     struct ath_tid *tid, ath_bufhead *bf_q)
733 {
734 	//struct ieee80211_node *ni = &an->an_node;
735 	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
736 	int nframes = 0;
737 	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
738 	struct ieee80211_tx_ampdu *tap;
739 	int status = ATH_AGGR_DONE;
740 	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
741 	int prev_al = 0;	/* XXX also for AR5416 burst */
742 
743 	ATH_TX_LOCK_ASSERT(sc);
744 
745 	tap = ath_tx_get_tx_tid(an, tid->tid);
746 	if (tap == NULL) {
747 		status = ATH_AGGR_ERROR;
748 		goto finish;
749 	}
750 
751 	h_baw = tap->txa_wnd / 2;
752 
753 	for (;;) {
754 		bf = ATH_TID_FIRST(tid);
755 		if (bf_first == NULL)
756 			bf_first = bf;
757 		if (bf == NULL) {
758 			status = ATH_AGGR_DONE;
759 			break;
760 		} else {
761 			/*
762 			 * It's the first frame;
763 			 * set the aggregation limit based on the
764 			 * rate control decision that has been made.
765 			 */
766 			aggr_limit = ath_get_aggr_limit(sc, bf_first);
767 		}
768 
769 		/* Set this early just so things don't get confused */
770 		bf->bf_next = NULL;
771 
772 		/*
773 		 * If the frame doesn't have a sequence number that we're
774 		 * tracking in the BAW (eg NULL QOS data frame), we can't
775 		 * aggregate it. Stop the aggregation process; the sender
776 		 * can then TX what's in the list thus far and then
777 		 * TX the frame individually.
778 		 */
779 		if (! bf->bf_state.bfs_dobaw) {
780 			status = ATH_AGGR_NONAGGR;
781 			break;
782 		}
783 
784 		/*
785 		 * If any of the rates are non-HT, this packet
786 		 * can't be aggregated.
787 		 * XXX TODO: add a bf_state flag which gets marked
788 		 * if any active rate is non-HT.
789 		 */
790 
791 		/*
792 		 * do not exceed aggregation limit
793 		 */
794 		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
795 		if (nframes &&
796 		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
797 			status = ATH_AGGR_LIMITED;
798 			break;
799 		}
800 
801 		/*
802 		 * If RTS/CTS is set on the first frame, enforce
803 		 * the RTS aggregate limit.
804 		 */
805 		if (bf_first->bf_state.bfs_txflags &
806 		    (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
807 			if (nframes &&
808 			   (sc->sc_rts_aggr_limit <
809 			     (al + bpad + al_delta + prev_al))) {
810 				status = ATH_AGGR_8K_LIMITED;
811 				break;
812 			}
813 		}
814 
815 		/*
816 		 * Do not exceed subframe limit.
817 		 */
818 		if ((nframes + prev_frames) >= MIN((h_baw),
819 		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
820 			status = ATH_AGGR_LIMITED;
821 			break;
822 		}
823 
824 		/*
825 		 * If the current frame has an RTS/CTS configuration
826 		 * that differs from the first frame, override the
827 		 * subsequent frame with this config.
828 		 */
829 		if (bf != bf_first) {
830 			bf->bf_state.bfs_txflags &=
831 			    ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
832 			bf->bf_state.bfs_txflags |=
833 			    bf_first->bf_state.bfs_txflags &
834 			    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
835 		}
836 
837 		/*
838 		 * If the packet has a sequence number, do not
839 		 * step outside of the block-ack window.
840 		 */
841 		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
842 		    SEQNO(bf->bf_state.bfs_seqno))) {
843 			status = ATH_AGGR_BAW_CLOSED;
844 			break;
845 		}
846 
847 		/*
848 		 * this packet is part of an aggregate.
849 		 */
850 		ATH_TID_REMOVE(tid, bf, bf_list);
851 
852 		/* The TID lock is required for the BAW update */
853 		ath_tx_addto_baw(sc, an, tid, bf);
854 		bf->bf_state.bfs_addedbaw = 1;
855 
856 		/*
857 		 * XXX enforce ACK for aggregate frames (this needs to be
858 		 * XXX handled more gracefully?
859 		 */
860 		if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
861 			device_printf(sc->sc_dev,
862 			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
863 			    __func__);
864 			bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
865 		}
866 
867 		/*
868 		 * Add the now owned buffer (which isn't
869 		 * on the software TXQ any longer) to our
870 		 * aggregate frame list.
871 		 */
872 		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
873 		nframes ++;
874 
875 		/* Completion handler */
876 		bf->bf_comp = ath_tx_aggr_comp;
877 
878 		/*
879 		 * add padding for previous frame to aggregation length
880 		 */
881 		al += bpad + al_delta;
882 
883 		/*
884 		 * Calculate delimiters needed for the current frame
885 		 */
886 		bf->bf_state.bfs_ndelim =
887 		    ath_compute_num_delims(sc, bf_first,
888 		    bf->bf_state.bfs_pktlen);
889 
890 		/*
891 		 * Calculate the padding needed from this set of delimiters,
892 		 * used when calculating if the next frame will fit in
893 		 * the aggregate.
894 		 */
895 		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
896 
897 		/*
898 		 * Chain the buffers together
899 		 */
900 		if (bf_prev)
901 			bf_prev->bf_next = bf;
902 		bf_prev = bf;
903 
904 		/*
905 		 * If we're leaking frames, just return at this point;
906 		 * we've queued a single frame and we don't want to add
907 		 * any more.
908 		 */
909 		if (tid->an->an_leak_count) {
910 			status = ATH_AGGR_LEAK_CLOSED;
911 			break;
912 		}
913 
914 #if 0
915 		/*
916 		 * terminate aggregation on a small packet boundary
917 		 */
918 		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
919 			status = ATH_AGGR_SHORTPKT;
920 			break;
921 		}
922 #endif
923 
924 	}
925 
926 finish:
927 	/*
928 	 * Just in case the list was empty when we tried to
929 	 * dequeue a packet ..
930 	 */
931 	if (bf_first) {
932 		bf_first->bf_state.bfs_al = al;
933 		bf_first->bf_state.bfs_nframes = nframes;
934 	}
935 	return status;
936 }
937