xref: /dragonfly/sys/dev/netif/ath/ath/if_ath_tx_ht.c (revision 0ca59c34)
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 <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/if_media.h>
58 #include <net/if_types.h>
59 #include <net/if_arp.h>
60 #include <net/ethernet.h>
61 #include <net/if_llc.h>
62 
63 #include <netproto/802_11/ieee80211_var.h>
64 #include <netproto/802_11/ieee80211_regdomain.h>
65 #ifdef IEEE80211_SUPPORT_SUPERG
66 #include <netproto/802_11/ieee80211_superg.h>
67 #endif
68 #ifdef IEEE80211_SUPPORT_TDMA
69 #include <netproto/802_11/ieee80211_tdma.h>
70 #endif
71 
72 #include <net/bpf.h>
73 
74 #ifdef INET
75 #include <netinet/in.h>
76 #include <netinet/if_ether.h>
77 #endif
78 
79 #include <dev/netif/ath/ath/if_athvar.h>
80 #include <dev/netif/ath/ath_hal/ah_devid.h>		/* XXX for softled */
81 #include <dev/netif/ath/ath_hal/ah_diagcodes.h>
82 
83 #ifdef ATH_TX99_DIAG
84 #include <dev/netif/ath/ath_tx99/ath_tx99.h>
85 #endif
86 
87 #include <dev/netif/ath/ath/if_ath_tx.h>		/* XXX for some support functions */
88 #include <dev/netif/ath/ath/if_ath_tx_ht.h>
89 #include <dev/netif/ath/ath/if_athrate.h>
90 #include <dev/netif/ath/ath/if_ath_debug.h>
91 
92 /*
93  * XXX net80211?
94  */
95 #define	IEEE80211_AMPDU_SUBFRAME_DEFAULT		32
96 
97 #define	ATH_AGGR_DELIM_SZ	4	/* delimiter size */
98 #define	ATH_AGGR_MINPLEN	256	/* in bytes, minimum packet length */
99 /* number of delimiters for encryption padding */
100 #define	ATH_AGGR_ENCRYPTDELIM	10
101 
102 /*
103  * returns delimiter padding required given the packet length
104  */
105 #define	ATH_AGGR_GET_NDELIM(_len)					\
106 	    (((((_len) + ATH_AGGR_DELIM_SZ) < ATH_AGGR_MINPLEN) ?	\
107 	    (ATH_AGGR_MINPLEN - (_len) - ATH_AGGR_DELIM_SZ) : 0) >> 2)
108 
109 #define	PADBYTES(_len)		((4 - ((_len) % 4)) % 4)
110 
111 int ath_max_4ms_framelen[4][32] = {
112 	[MCS_HT20] = {
113 		3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
114 		6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
115 		9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
116 		12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
117 	},
118 	[MCS_HT20_SGI] = {
119 		3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
120 		7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
121 		10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
122 		14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
123 	},
124 	[MCS_HT40] = {
125 		6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
126 		13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
127 		20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
128 		26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
129 	},
130 	[MCS_HT40_SGI] = {
131 		7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
132 		14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
133 		22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
134 		29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
135 	}
136 };
137 
138 /*
139  * XXX should be in net80211
140  */
141 static int ieee80211_mpdudensity_map[] = {
142 	0,		/* IEEE80211_HTCAP_MPDUDENSITY_NA */
143 	25,		/* IEEE80211_HTCAP_MPDUDENSITY_025 */
144 	50,		/* IEEE80211_HTCAP_MPDUDENSITY_05 */
145 	100,		/* IEEE80211_HTCAP_MPDUDENSITY_1 */
146 	200,		/* IEEE80211_HTCAP_MPDUDENSITY_2 */
147 	400,		/* IEEE80211_HTCAP_MPDUDENSITY_4 */
148 	800,		/* IEEE80211_HTCAP_MPDUDENSITY_8 */
149 	1600,		/* IEEE80211_HTCAP_MPDUDENSITY_16 */
150 };
151 
152 /*
153  * XXX should be in the HAL/net80211 ?
154  */
155 #define	BITS_PER_BYTE		8
156 #define	OFDM_PLCP_BITS		22
157 #define	HT_RC_2_MCS(_rc)	((_rc) & 0x7f)
158 #define	HT_RC_2_STREAMS(_rc)	((((_rc) & 0x78) >> 3) + 1)
159 #define	L_STF			8
160 #define	L_LTF			8
161 #define	L_SIG			4
162 #define	HT_SIG			8
163 #define	HT_STF			4
164 #define	HT_LTF(_ns)		(4 * (_ns))
165 #define	SYMBOL_TIME(_ns)	((_ns) << 2)		// ns * 4 us
166 #define	SYMBOL_TIME_HALFGI(_ns)	(((_ns) * 18 + 4) / 5)	// ns * 3.6 us
167 #define	NUM_SYMBOLS_PER_USEC(_usec)	(_usec >> 2)
168 #define	NUM_SYMBOLS_PER_USEC_HALFGI(_usec)	(((_usec*5)-4)/18)
169 #define	IS_HT_RATE(_rate)	((_rate) & 0x80)
170 
171 const uint32_t bits_per_symbol[][2] = {
172     /* 20MHz 40MHz */
173     {    26,   54 },     //  0: BPSK
174     {    52,  108 },     //  1: QPSK 1/2
175     {    78,  162 },     //  2: QPSK 3/4
176     {   104,  216 },     //  3: 16-QAM 1/2
177     {   156,  324 },     //  4: 16-QAM 3/4
178     {   208,  432 },     //  5: 64-QAM 2/3
179     {   234,  486 },     //  6: 64-QAM 3/4
180     {   260,  540 },     //  7: 64-QAM 5/6
181     {    52,  108 },     //  8: BPSK
182     {   104,  216 },     //  9: QPSK 1/2
183     {   156,  324 },     // 10: QPSK 3/4
184     {   208,  432 },     // 11: 16-QAM 1/2
185     {   312,  648 },     // 12: 16-QAM 3/4
186     {   416,  864 },     // 13: 64-QAM 2/3
187     {   468,  972 },     // 14: 64-QAM 3/4
188     {   520, 1080 },     // 15: 64-QAM 5/6
189     {    78,  162 },     // 16: BPSK
190     {   156,  324 },     // 17: QPSK 1/2
191     {   234,  486 },     // 18: QPSK 3/4
192     {   312,  648 },     // 19: 16-QAM 1/2
193     {   468,  972 },     // 20: 16-QAM 3/4
194     {   624, 1296 },     // 21: 64-QAM 2/3
195     {   702, 1458 },     // 22: 64-QAM 3/4
196     {   780, 1620 },     // 23: 64-QAM 5/6
197     {   104,  216 },     // 24: BPSK
198     {   208,  432 },     // 25: QPSK 1/2
199     {   312,  648 },     // 26: QPSK 3/4
200     {   416,  864 },     // 27: 16-QAM 1/2
201     {   624, 1296 },     // 28: 16-QAM 3/4
202     {   832, 1728 },     // 29: 64-QAM 2/3
203     {   936, 1944 },     // 30: 64-QAM 3/4
204     {  1040, 2160 },     // 31: 64-QAM 5/6
205 };
206 
207 /*
208  * Fill in the rate array information based on the current
209  * node configuration and the choices made by the rate
210  * selection code and ath_buf setup code.
211  *
212  * Later on, this may end up also being made by the
213  * rate control code, but for now it can live here.
214  *
215  * This needs to be called just before the packet is
216  * queued to the software queue or hardware queue,
217  * so all of the needed fields in bf_state are setup.
218  */
219 void
220 ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
221 {
222 	struct ieee80211_node *ni = bf->bf_node;
223 	struct ieee80211com *ic = ni->ni_ic;
224 	const HAL_RATE_TABLE *rt = sc->sc_currates;
225 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
226 	uint8_t rate;
227 	int i;
228 
229 	for (i = 0; i < ATH_RC_NUM; i++) {
230 		rc[i].flags = 0;
231 		if (rc[i].tries == 0)
232 			continue;
233 
234 		rate = rt->info[rc[i].rix].rateCode;
235 
236 		/*
237 		 * Only enable short preamble for legacy rates
238 		 */
239 		if ((! IS_HT_RATE(rate)) && bf->bf_state.bfs_shpream)
240 			rate |= rt->info[rc[i].rix].shortPreamble;
241 
242 		/*
243 		 * Save this, used by the TX and completion code
244 		 */
245 		rc[i].ratecode = rate;
246 
247 		if (bf->bf_state.bfs_txflags &
248 		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
249 			rc[i].flags |= ATH_RC_RTSCTS_FLAG;
250 
251 		/* Only enable shortgi, 2040, dual-stream if HT is set */
252 		if (IS_HT_RATE(rate)) {
253 			rc[i].flags |= ATH_RC_HT_FLAG;
254 
255 			if (ni->ni_chw == 40)
256 				rc[i].flags |= ATH_RC_CW40_FLAG;
257 
258 			if (ni->ni_chw == 40 &&
259 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
260 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
261 				rc[i].flags |= ATH_RC_SGI_FLAG;
262 
263 			if (ni->ni_chw == 20 &&
264 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
265 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
266 				rc[i].flags |= ATH_RC_SGI_FLAG;
267 
268 			/*
269 			 * If we have STBC TX enabled and the receiver
270 			 * can receive (at least) 1 stream STBC, AND it's
271 			 * MCS 0-7, AND we have at least two chains enabled,
272 			 * enable STBC.
273 			 */
274 			if (ic->ic_htcaps & IEEE80211_HTCAP_TXSTBC &&
275 			    ni->ni_htcap & IEEE80211_HTCAP_RXSTBC_1STREAM &&
276 			    (sc->sc_cur_txchainmask > 1) &&
277 			    HT_RC_2_STREAMS(rate) == 1) {
278 				rc[i].flags |= ATH_RC_STBC_FLAG;
279 			}
280 
281 			/*
282 			 * XXX TODO: LDPC
283 			 */
284 
285 			/*
286 			 * Dual / Triple stream rate?
287 			 */
288 			if (HT_RC_2_STREAMS(rate) == 2)
289 				rc[i].flags |= ATH_RC_DS_FLAG;
290 			else if (HT_RC_2_STREAMS(rate) == 3)
291 				rc[i].flags |= ATH_RC_TS_FLAG;
292 		}
293 
294 		/*
295 		 * Calculate the maximum TX power cap for the current
296 		 * node.
297 		 */
298 		rc[i].tx_power_cap = ieee80211_get_node_txpower(ni);
299 
300 		/*
301 		 * Calculate the maximum 4ms frame length based
302 		 * on the MCS rate, SGI and channel width flags.
303 		 */
304 		if ((rc[i].flags & ATH_RC_HT_FLAG) &&
305 		    (HT_RC_2_MCS(rate) < 32)) {
306 			int j;
307 			if (rc[i].flags & ATH_RC_CW40_FLAG) {
308 				if (rc[i].flags & ATH_RC_SGI_FLAG)
309 					j = MCS_HT40_SGI;
310 				else
311 					j = MCS_HT40;
312 			} else {
313 				if (rc[i].flags & ATH_RC_SGI_FLAG)
314 					j = MCS_HT20_SGI;
315 				else
316 					j = MCS_HT20;
317 			}
318 			rc[i].max4msframelen =
319 			    ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
320 		} else
321 			rc[i].max4msframelen = 0;
322 		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
323 		    "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
324 		    __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
325 	}
326 }
327 
328 /*
329  * Return the number of delimiters to be added to
330  * meet the minimum required mpdudensity.
331  *
332  * Caller should make sure that the rate is HT.
333  *
334  * TODO: is this delimiter calculation supposed to be the
335  * total frame length, the hdr length, the data length (including
336  * delimiters, padding, CRC, etc) or ?
337  *
338  * TODO: this should ensure that the rate control information
339  * HAS been setup for the first rate.
340  *
341  * TODO: ensure this is only called for MCS rates.
342  *
343  * TODO: enforce MCS < 31
344  */
345 static int
346 ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
347     uint16_t pktlen)
348 {
349 	const HAL_RATE_TABLE *rt = sc->sc_currates;
350 	struct ieee80211_node *ni = first_bf->bf_node;
351 	struct ieee80211vap *vap = ni->ni_vap;
352 	int ndelim, mindelim = 0;
353 	int mpdudensity;	 /* in 1/100'th of a microsecond */
354 	uint8_t rc, rix, flags;
355 	int width, half_gi;
356 	uint32_t nsymbits, nsymbols;
357 	uint16_t minlen;
358 
359 	/*
360 	 * vap->iv_ampdu_density is a value, rather than the actual
361 	 * density.
362 	 */
363 	if (vap->iv_ampdu_density > IEEE80211_HTCAP_MPDUDENSITY_16)
364 		mpdudensity = 1600;		/* maximum density */
365 	else
366 		mpdudensity = ieee80211_mpdudensity_map[vap->iv_ampdu_density];
367 
368 	/* Select standard number of delimiters based on frame length */
369 	ndelim = ATH_AGGR_GET_NDELIM(pktlen);
370 
371 	/*
372 	 * If encryption is enabled, add extra delimiters to let the
373 	 * crypto hardware catch up. This could be tuned per-MAC and
374 	 * per-rate, but for now we'll simply assume encryption is
375 	 * always enabled.
376 	 *
377 	 * Also note that the Atheros reference driver inserts two
378 	 * delimiters by default for pre-AR9380 peers.  This will
379 	 * include "that" required delimiter.
380 	 */
381 	ndelim += ATH_AGGR_ENCRYPTDELIM;
382 
383 	/*
384 	 * For AR9380, there's a minimum number of delimeters
385 	 * required when doing RTS.
386 	 *
387 	 * XXX TODO: this is only needed if (a) RTS/CTS is enabled, and
388 	 * XXX (b) this is the first sub-frame in the aggregate.
389 	 */
390 	if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
391 	    && ndelim < AH_FIRST_DESC_NDELIMS)
392 		ndelim = AH_FIRST_DESC_NDELIMS;
393 
394 	/*
395 	 * If sc_delim_min_pad is non-zero, enforce it as the minimum
396 	 * pad delimiter count.
397 	 */
398 	if (sc->sc_delim_min_pad != 0)
399 		ndelim = MAX(ndelim, sc->sc_delim_min_pad);
400 
401 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
402 	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
403 	    __func__, pktlen, ndelim, mpdudensity);
404 
405 	/*
406 	 * If the MPDU density is 0, we can return here.
407 	 * Otherwise, we need to convert the desired mpdudensity
408 	 * into a byte length, based on the rate in the subframe.
409 	 */
410 	if (mpdudensity == 0)
411 		return ndelim;
412 
413 	/*
414 	 * Convert desired mpdu density from microeconds to bytes based
415 	 * on highest rate in rate series (i.e. first rate) to determine
416 	 * required minimum length for subframe. Take into account
417 	 * whether high rate is 20 or 40Mhz and half or full GI.
418 	 */
419 	rix = first_bf->bf_state.bfs_rc[0].rix;
420 	rc = rt->info[rix].rateCode;
421 	flags = first_bf->bf_state.bfs_rc[0].flags;
422 	width = !! (flags & ATH_RC_CW40_FLAG);
423 	half_gi = !! (flags & ATH_RC_SGI_FLAG);
424 
425 	/*
426 	 * mpdudensity is in 1/100th of a usec, so divide by 100
427 	 */
428 	if (half_gi)
429 		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
430 	else
431 		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
432 	nsymbols /= 100;
433 
434 	if (nsymbols == 0)
435 		nsymbols = 1;
436 
437 	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
438 	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
439 
440 	/*
441 	 * Min length is the minimum frame length for the
442 	 * required MPDU density.
443 	 */
444 	if (pktlen < minlen) {
445 		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
446 		ndelim = MAX(mindelim, ndelim);
447 	}
448 
449 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
450 	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
451 	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
452 
453 	return ndelim;
454 }
455 
456 /*
457  * Fetch the aggregation limit.
458  *
459  * It's the lowest of the four rate series 4ms frame length.
460  */
461 static int
462 ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
463 {
464 	int amin = ATH_AGGR_MAXSIZE;
465 	int i;
466 
467 	if (sc->sc_aggr_limit > 0 && sc->sc_aggr_limit < ATH_AGGR_MAXSIZE)
468 		amin = sc->sc_aggr_limit;
469 
470 	for (i = 0; i < ATH_RC_NUM; i++) {
471 		if (bf->bf_state.bfs_rc[i].tries == 0)
472 			continue;
473 		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
474 	}
475 
476 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
477 	    __func__, amin);
478 
479 	return amin;
480 }
481 
482 /*
483  * Setup a 11n rate series structure
484  *
485  * This should be called for both legacy and MCS rates.
486  *
487  * This uses the rate series stuf from ath_tx_rate_fill_rcflags().
488  *
489  * It, along with ath_buf_set_rate, must be called -after- a burst
490  * or aggregate is setup.
491  */
492 static void
493 ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
494     struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
495 {
496 	struct ieee80211com *ic = ni->ni_ic;
497 	struct ath_hal *ah = sc->sc_ah;
498 	HAL_BOOL shortPreamble = AH_FALSE;
499 	const HAL_RATE_TABLE *rt = sc->sc_currates;
500 	int i;
501 	int pktlen;
502 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
503 
504 	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
505 	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
506 		shortPreamble = AH_TRUE;
507 
508 	/*
509 	 * If this is the first frame in an aggregate series,
510 	 * use the aggregate length.
511 	 */
512 	if (bf->bf_state.bfs_aggr)
513 		pktlen = bf->bf_state.bfs_al;
514 	else
515 		pktlen = bf->bf_state.bfs_pktlen;
516 
517 	/*
518 	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
519 	 * XXX fields.
520 	 */
521 	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
522 	for (i = 0; i < ATH_RC_NUM;  i++) {
523 		/* Only set flags for actual TX attempts */
524 		if (rc[i].tries == 0)
525 			continue;
526 
527 		series[i].Tries = rc[i].tries;
528 
529 		/*
530 		 * XXX TODO: When the NIC is capable of three stream TX,
531 		 * transmit 1/2 stream rates on two streams.
532 		 *
533 		 * This reduces the power consumption of the NIC and
534 		 * keeps it within the PCIe slot power limits.
535 		 */
536 		series[i].ChSel = sc->sc_cur_txchainmask;
537 
538 		/*
539 		 * Setup rate and TX power cap for this series.
540 		 */
541 		series[i].Rate = rt->info[rc[i].rix].rateCode;
542 		series[i].RateIndex = rc[i].rix;
543 		series[i].tx_power_cap = rc[i].tx_power_cap;
544 
545 		/*
546 		 * Enable RTS/CTS as appropriate.
547 		 */
548 		if (rc[i].flags & ATH_RC_RTSCTS_FLAG)
549 			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
550 
551 		/*
552 		 * 11n rate? Update 11n flags.
553 		 */
554 		if (rc[i].flags & ATH_RC_HT_FLAG) {
555 			if (rc[i].flags & ATH_RC_CW40_FLAG)
556 				series[i].RateFlags |= HAL_RATESERIES_2040;
557 
558 			if (rc[i].flags & ATH_RC_SGI_FLAG)
559 				series[i].RateFlags |= HAL_RATESERIES_HALFGI;
560 
561 			if (rc[i].flags & ATH_RC_STBC_FLAG)
562 				series[i].RateFlags |= HAL_RATESERIES_STBC;
563 		}
564 
565 		/*
566 		 * PktDuration doesn't include slot, ACK, RTS, etc timing -
567 		 * it's just the packet duration
568 		 */
569 		if (rc[i].flags & ATH_RC_HT_FLAG) {
570 			series[i].PktDuration =
571 			    ath_computedur_ht(pktlen
572 				, series[i].Rate
573 				, HT_RC_2_STREAMS(series[i].Rate)
574 				, series[i].RateFlags & HAL_RATESERIES_2040
575 				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
576 		} else {
577 			if (shortPreamble)
578 				series[i].Rate |=
579 				    rt->info[rc[i].rix].shortPreamble;
580 			series[i].PktDuration = ath_hal_computetxtime(ah,
581 			    rt, pktlen, rc[i].rix, shortPreamble);
582 		}
583 	}
584 }
585 
586 #if 0
587 static void
588 ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
589 {
590 	int i;
591 	for (i = 0; i < ATH_RC_NUM; i++) {
592 		device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
593 		    "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
594 		    i,
595 		    series[i].Rate,
596 		    series[i].Tries,
597 		    series[i].PktDuration,
598 		    series[i].ChSel,
599 		    series[i].tx_power_cap,
600 		    series[i].RateFlags);
601 	}
602 }
603 #endif
604 
605 /*
606  * Setup the 11n rate scenario and burst duration for the given TX descriptor
607  * list.
608  *
609  * This isn't useful for sending beacon frames, which has different needs
610  * wrt what's passed into the rate scenario function.
611  */
612 void
613 ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
614     struct ath_buf *bf)
615 {
616 	HAL_11N_RATE_SERIES series[4];
617 	struct ath_desc *ds = bf->bf_desc;
618 	struct ath_hal *ah = sc->sc_ah;
619 	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
620 	int ctsrate = bf->bf_state.bfs_ctsrate;
621 	int flags = bf->bf_state.bfs_txflags;
622 
623 	/* Setup rate scenario */
624 	memset(&series, 0, sizeof(series));
625 
626 	ath_rateseries_setup(sc, ni, bf, series);
627 
628 #if 0
629 	ath_rateseries_print(sc, series);
630 #endif
631 
632 	/* Set rate scenario */
633 	/*
634 	 * Note: Don't allow hardware to override the duration on
635 	 * ps-poll packets.
636 	 */
637 	ath_hal_set11nratescenario(ah, ds,
638 	    !is_pspoll,	/* whether to override the duration or not */
639 	    ctsrate,	/* rts/cts rate */
640 	    series,	/* 11n rate series */
641 	    4,		/* number of series */
642 	    flags);
643 
644 	/* Set burst duration */
645 	/*
646 	 * This is only required when doing 11n burst, not aggregation
647 	 * ie, if there's a second frame in a RIFS or A-MPDU burst
648 	 * w/ >1 A-MPDU frame bursting back to back.
649 	 * Normal A-MPDU doesn't do bursting -between- aggregates.
650 	 *
651 	 * .. and it's highly likely this won't ever be implemented
652 	 */
653 	//ath_hal_set11nburstduration(ah, ds, 8192);
654 }
655 
656 /*
657  * Form an aggregate packet list.
658  *
659  * This function enforces the aggregate restrictions/requirements.
660  *
661  * These are:
662  *
663  * + The aggregate size maximum (64k for AR9160 and later, 8K for
664  *   AR5416 when doing RTS frame protection.)
665  * + Maximum number of sub-frames for an aggregate
666  * + The aggregate delimiter size, giving MACs time to do whatever is
667  *   needed before each frame
668  * + Enforce the BAW limit
669  *
670  * Each descriptor queued should have the DMA setup.
671  * The rate series, descriptor setup, linking, etc is all done
672  * externally. This routine simply chains them together.
673  * ath_tx_setds_11n() will take care of configuring the per-
674  * descriptor setup, and ath_buf_set_rate() will configure the
675  * rate control.
676  *
677  * The TID lock is required for the entirety of this function.
678  *
679  * If some code in another thread adds to the head of this
680  * list, very strange behaviour will occur. Since retransmission is the
681  * only reason this will occur, and this routine is designed to be called
682  * from within the scheduler task, it won't ever clash with the completion
683  * task.
684  *
685  * So if you want to call this from an upper layer context (eg, to direct-
686  * dispatch aggregate frames to the hardware), please keep this in mind.
687  */
688 ATH_AGGR_STATUS
689 ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
690     struct ath_tid *tid, ath_bufhead *bf_q)
691 {
692 	//struct ieee80211_node *ni = &an->an_node;
693 	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
694 	int nframes = 0;
695 	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
696 	struct ieee80211_tx_ampdu *tap;
697 	int status = ATH_AGGR_DONE;
698 	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
699 	int prev_al = 0;	/* XXX also for AR5416 burst */
700 
701 	ATH_TX_LOCK_ASSERT(sc);
702 
703 	tap = ath_tx_get_tx_tid(an, tid->tid);
704 	if (tap == NULL) {
705 		status = ATH_AGGR_ERROR;
706 		goto finish;
707 	}
708 
709 	h_baw = tap->txa_wnd / 2;
710 
711 	for (;;) {
712 		bf = ATH_TID_FIRST(tid);
713 		if (bf_first == NULL)
714 			bf_first = bf;
715 		if (bf == NULL) {
716 			status = ATH_AGGR_DONE;
717 			break;
718 		} else {
719 			/*
720 			 * It's the first frame;
721 			 * set the aggregation limit based on the
722 			 * rate control decision that has been made.
723 			 */
724 			aggr_limit = ath_get_aggr_limit(sc, bf_first);
725 		}
726 
727 		/* Set this early just so things don't get confused */
728 		bf->bf_next = NULL;
729 
730 		/*
731 		 * If the frame doesn't have a sequence number that we're
732 		 * tracking in the BAW (eg NULL QOS data frame), we can't
733 		 * aggregate it. Stop the aggregation process; the sender
734 		 * can then TX what's in the list thus far and then
735 		 * TX the frame individually.
736 		 */
737 		if (! bf->bf_state.bfs_dobaw) {
738 			status = ATH_AGGR_NONAGGR;
739 			break;
740 		}
741 
742 		/*
743 		 * If any of the rates are non-HT, this packet
744 		 * can't be aggregated.
745 		 * XXX TODO: add a bf_state flag which gets marked
746 		 * if any active rate is non-HT.
747 		 */
748 
749 		/*
750 		 * do not exceed aggregation limit
751 		 */
752 		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
753 		if (nframes &&
754 		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
755 			status = ATH_AGGR_LIMITED;
756 			break;
757 		}
758 
759 		/*
760 		 * If RTS/CTS is set on the first frame, enforce
761 		 * the RTS aggregate limit.
762 		 */
763 		if (bf_first->bf_state.bfs_txflags &
764 		    (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
765 			if (nframes &&
766 			   (sc->sc_rts_aggr_limit <
767 			     (al + bpad + al_delta + prev_al))) {
768 				status = ATH_AGGR_8K_LIMITED;
769 				break;
770 			}
771 		}
772 
773 		/*
774 		 * Do not exceed subframe limit.
775 		 */
776 		if ((nframes + prev_frames) >= MIN((h_baw),
777 		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
778 			status = ATH_AGGR_LIMITED;
779 			break;
780 		}
781 
782 		/*
783 		 * If the current frame has an RTS/CTS configuration
784 		 * that differs from the first frame, override the
785 		 * subsequent frame with this config.
786 		 */
787 		if (bf != bf_first) {
788 			bf->bf_state.bfs_txflags &=
789 			    ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
790 			bf->bf_state.bfs_txflags |=
791 			    bf_first->bf_state.bfs_txflags &
792 			    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
793 		}
794 
795 		/*
796 		 * If the packet has a sequence number, do not
797 		 * step outside of the block-ack window.
798 		 */
799 		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
800 		    SEQNO(bf->bf_state.bfs_seqno))) {
801 			status = ATH_AGGR_BAW_CLOSED;
802 			break;
803 		}
804 
805 		/*
806 		 * this packet is part of an aggregate.
807 		 */
808 		ATH_TID_REMOVE(tid, bf, bf_list);
809 
810 		/* The TID lock is required for the BAW update */
811 		ath_tx_addto_baw(sc, an, tid, bf);
812 		bf->bf_state.bfs_addedbaw = 1;
813 
814 		/*
815 		 * XXX enforce ACK for aggregate frames (this needs to be
816 		 * XXX handled more gracefully?
817 		 */
818 		if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
819 			device_printf(sc->sc_dev,
820 			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
821 			    __func__);
822 			bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
823 		}
824 
825 		/*
826 		 * Add the now owned buffer (which isn't
827 		 * on the software TXQ any longer) to our
828 		 * aggregate frame list.
829 		 */
830 		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
831 		nframes ++;
832 
833 		/* Completion handler */
834 		bf->bf_comp = ath_tx_aggr_comp;
835 
836 		/*
837 		 * add padding for previous frame to aggregation length
838 		 */
839 		al += bpad + al_delta;
840 
841 		/*
842 		 * Calculate delimiters needed for the current frame
843 		 */
844 		bf->bf_state.bfs_ndelim =
845 		    ath_compute_num_delims(sc, bf_first,
846 		    bf->bf_state.bfs_pktlen);
847 
848 		/*
849 		 * Calculate the padding needed from this set of delimiters,
850 		 * used when calculating if the next frame will fit in
851 		 * the aggregate.
852 		 */
853 		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
854 
855 		/*
856 		 * Chain the buffers together
857 		 */
858 		if (bf_prev)
859 			bf_prev->bf_next = bf;
860 		bf_prev = bf;
861 
862 		/*
863 		 * If we're leaking frames, just return at this point;
864 		 * we've queued a single frame and we don't want to add
865 		 * any more.
866 		 */
867 		if (tid->an->an_leak_count) {
868 			status = ATH_AGGR_LEAK_CLOSED;
869 			break;
870 		}
871 
872 #if 0
873 		/*
874 		 * terminate aggregation on a small packet boundary
875 		 */
876 		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
877 			status = ATH_AGGR_SHORTPKT;
878 			break;
879 		}
880 #endif
881 
882 	}
883 
884 finish:
885 	/*
886 	 * Just in case the list was empty when we tried to
887 	 * dequeue a packet ..
888 	 */
889 	if (bf_first) {
890 		bf_first->bf_state.bfs_al = al;
891 		bf_first->bf_state.bfs_nframes = nframes;
892 	}
893 	return status;
894 }
895