xref: /freebsd/sys/dev/ath/if_ath_tx_ht.c (revision c6ec7d31830ab1c80edae95ad5e4b9dba10c47ac)
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 
231 	for (i = 0; i < ATH_RC_NUM; i++) {
232 		rc[i].flags = 0;
233 		if (rc[i].tries == 0)
234 			continue;
235 
236 		rate = rt->info[rc[i].rix].rateCode;
237 
238 		/*
239 		 * XXX only do this for legacy rates?
240 		 */
241 		if (bf->bf_state.bfs_shpream)
242 			rate |= rt->info[rc[i].rix].shortPreamble;
243 
244 		/*
245 		 * Save this, used by the TX and completion code
246 		 */
247 		rc[i].ratecode = rate;
248 
249 		if (bf->bf_state.bfs_txflags &
250 		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
251 			rc[i].flags |= ATH_RC_RTSCTS_FLAG;
252 
253 		/* Only enable shortgi, 2040, dual-stream if HT is set */
254 		if (IS_HT_RATE(rate)) {
255 			rc[i].flags |= ATH_RC_HT_FLAG;
256 
257 			if (ni->ni_chw == 40)
258 				rc[i].flags |= ATH_RC_CW40_FLAG;
259 
260 			if (ni->ni_chw == 40 &&
261 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
262 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
263 				rc[i].flags |= ATH_RC_SGI_FLAG;
264 
265 			if (ni->ni_chw == 20 &&
266 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
267 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
268 				rc[i].flags |= ATH_RC_SGI_FLAG;
269 
270 			/* XXX dual stream? and 3-stream? */
271 		}
272 
273 		/*
274 		 * Calculate the maximum 4ms frame length based
275 		 * on the MCS rate, SGI and channel width flags.
276 		 */
277 		if ((rc[i].flags & ATH_RC_HT_FLAG) &&
278 		    (HT_RC_2_MCS(rate) < 32)) {
279 			int j;
280 			if (rc[i].flags & ATH_RC_CW40_FLAG) {
281 				if (rc[i].flags & ATH_RC_SGI_FLAG)
282 					j = MCS_HT40_SGI;
283 				else
284 					j = MCS_HT40;
285 			} else {
286 				if (rc[i].flags & ATH_RC_SGI_FLAG)
287 					j = MCS_HT20_SGI;
288 				else
289 					j = MCS_HT20;
290 			}
291 			rc[i].max4msframelen =
292 			    ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
293 		} else
294 			rc[i].max4msframelen = 0;
295 		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
296 		    "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
297 		    __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
298 	}
299 }
300 
301 /*
302  * Return the number of delimiters to be added to
303  * meet the minimum required mpdudensity.
304  *
305  * Caller should make sure that the rate is HT.
306  *
307  * TODO: is this delimiter calculation supposed to be the
308  * total frame length, the hdr length, the data length (including
309  * delimiters, padding, CRC, etc) or ?
310  *
311  * TODO: this should ensure that the rate control information
312  * HAS been setup for the first rate.
313  *
314  * TODO: ensure this is only called for MCS rates.
315  *
316  * TODO: enforce MCS < 31
317  */
318 static int
319 ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
320     uint16_t pktlen)
321 {
322 	const HAL_RATE_TABLE *rt = sc->sc_currates;
323 	struct ieee80211_node *ni = first_bf->bf_node;
324 	struct ieee80211vap *vap = ni->ni_vap;
325 	int ndelim, mindelim = 0;
326 	int mpdudensity;	 /* in 1/100'th of a microsecond */
327 	uint8_t rc, rix, flags;
328 	int width, half_gi;
329 	uint32_t nsymbits, nsymbols;
330 	uint16_t minlen;
331 
332 	/*
333 	 * vap->iv_ampdu_density is a value, rather than the actual
334 	 * density.
335 	 */
336 	if (vap->iv_ampdu_density > IEEE80211_HTCAP_MPDUDENSITY_16)
337 		mpdudensity = 1600;		/* maximum density */
338 	else
339 		mpdudensity = ieee80211_mpdudensity_map[vap->iv_ampdu_density];
340 
341 	/* Select standard number of delimiters based on frame length */
342 	ndelim = ATH_AGGR_GET_NDELIM(pktlen);
343 
344 	/*
345 	 * If encryption is enabled, add extra delimiters to let the
346 	 * crypto hardware catch up. This could be tuned per-MAC and
347 	 * per-rate, but for now we'll simply assume encryption is
348 	 * always enabled.
349 	 */
350 	ndelim += ATH_AGGR_ENCRYPTDELIM;
351 
352 	/*
353 	 * For AR9380, there's a minimum number of delimeters
354 	 * required when doing RTS.
355 	 */
356 	if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
357 	    && ndelim < AH_FIRST_DESC_NDELIMS)
358 		ndelim = AH_FIRST_DESC_NDELIMS;
359 
360 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
361 	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
362 	    __func__, pktlen, ndelim, mpdudensity);
363 
364 	/*
365 	 * If the MPDU density is 0, we can return here.
366 	 * Otherwise, we need to convert the desired mpdudensity
367 	 * into a byte length, based on the rate in the subframe.
368 	 */
369 	if (mpdudensity == 0)
370 		return ndelim;
371 
372 	/*
373 	 * Convert desired mpdu density from microeconds to bytes based
374 	 * on highest rate in rate series (i.e. first rate) to determine
375 	 * required minimum length for subframe. Take into account
376 	 * whether high rate is 20 or 40Mhz and half or full GI.
377 	 */
378 	rix = first_bf->bf_state.bfs_rc[0].rix;
379 	rc = rt->info[rix].rateCode;
380 	flags = first_bf->bf_state.bfs_rc[0].flags;
381 	width = !! (flags & ATH_RC_CW40_FLAG);
382 	half_gi = !! (flags & ATH_RC_SGI_FLAG);
383 
384 	/*
385 	 * mpdudensity is in 1/100th of a usec, so divide by 100
386 	 */
387 	if (half_gi)
388 		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
389 	else
390 		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
391 	nsymbols /= 100;
392 
393 	if (nsymbols == 0)
394 		nsymbols = 1;
395 
396 	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
397 	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
398 
399 	/*
400 	 * Min length is the minimum frame length for the
401 	 * required MPDU density.
402 	 */
403 	if (pktlen < minlen) {
404 		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
405 		ndelim = MAX(mindelim, ndelim);
406 	}
407 
408 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
409 	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
410 	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
411 
412 	return ndelim;
413 }
414 
415 /*
416  * Fetch the aggregation limit.
417  *
418  * It's the lowest of the four rate series 4ms frame length.
419  */
420 static int
421 ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
422 {
423 	int amin = 65530;
424 	int i;
425 
426 	for (i = 0; i < ATH_RC_NUM; i++) {
427 		if (bf->bf_state.bfs_rc[i].tries == 0)
428 			continue;
429 		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
430 	}
431 
432 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
433 	    __func__, amin);
434 
435 	return amin;
436 }
437 
438 /*
439  * Setup a 11n rate series structure
440  *
441  * This should be called for both legacy and MCS rates.
442  *
443  * It, along with ath_buf_set_rate, must be called -after- a burst
444  * or aggregate is setup.
445  */
446 static void
447 ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
448     struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
449 {
450 	struct ieee80211com *ic = ni->ni_ic;
451 	struct ath_hal *ah = sc->sc_ah;
452 	HAL_BOOL shortPreamble = AH_FALSE;
453 	const HAL_RATE_TABLE *rt = sc->sc_currates;
454 	int i;
455 	int pktlen;
456 	int flags = bf->bf_state.bfs_txflags;
457 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
458 
459 	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
460 	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
461 		shortPreamble = AH_TRUE;
462 
463 	/*
464 	 * If this is the first frame in an aggregate series,
465 	 * use the aggregate length.
466 	 */
467 	if (bf->bf_state.bfs_aggr)
468 		pktlen = bf->bf_state.bfs_al;
469 	else
470 		pktlen = bf->bf_state.bfs_pktlen;
471 
472 	/*
473 	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
474 	 * XXX fields.
475 	 */
476 	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
477 	for (i = 0; i < ATH_RC_NUM;  i++) {
478 		/* Only set flags for actual TX attempts */
479 		if (rc[i].tries == 0)
480 			continue;
481 
482 		series[i].Tries = rc[i].tries;
483 
484 		/*
485 		 * XXX this isn't strictly correct - sc_txchainmask
486 		 * XXX isn't the currently active chainmask;
487 		 * XXX it's the interface chainmask at startup.
488 		 * XXX It's overridden in the HAL rate scenario function
489 		 * XXX for now.
490 		 */
491 		series[i].ChSel = sc->sc_txchainmask;
492 
493 		if (flags & (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
494 			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
495 
496 		/*
497 		 * Transmit 40MHz frames only if the node has negotiated
498 		 * it rather than whether the node is capable of it or not.
499 	 	 * It's subtly different in the hostap case.
500 	 	 */
501 		if (ni->ni_chw == 40)
502 			series[i].RateFlags |= HAL_RATESERIES_2040;
503 
504 		/*
505 		 * Set short-GI only if the node has advertised it
506 		 * the channel width is suitable, and we support it.
507 		 * We don't currently have a "negotiated" set of bits -
508 		 * ni_htcap is what the remote end sends, not what this
509 		 * node is capable of.
510 		 */
511 		if (ni->ni_chw == 40 &&
512 		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
513 		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
514 			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
515 
516 		if (ni->ni_chw == 20 &&
517 		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
518 		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
519 			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
520 
521 		series[i].Rate = rt->info[rc[i].rix].rateCode;
522 		series[i].RateIndex = rc[i].rix;
523 		series[i].tx_power_cap = 0x3f;	/* XXX for now */
524 
525 		/*
526 		 * PktDuration doesn't include slot, ACK, RTS, etc timing -
527 		 * it's just the packet duration
528 		 */
529 		if (series[i].Rate & IEEE80211_RATE_MCS) {
530 			series[i].PktDuration =
531 			    ath_computedur_ht(pktlen
532 				, series[i].Rate
533 				, HT_RC_2_STREAMS(series[i].Rate)
534 				, series[i].RateFlags & HAL_RATESERIES_2040
535 				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
536 		} else {
537 			if (shortPreamble)
538 				series[i].Rate |=
539 				    rt->info[rc[i].rix].shortPreamble;
540 			series[i].PktDuration = ath_hal_computetxtime(ah,
541 			    rt, pktlen, rc[i].rix, shortPreamble);
542 		}
543 	}
544 }
545 
546 #if 0
547 static void
548 ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
549 {
550 	int i;
551 	for (i = 0; i < ATH_RC_NUM; i++) {
552 		device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
553 		    "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
554 		    i,
555 		    series[i].Rate,
556 		    series[i].Tries,
557 		    series[i].PktDuration,
558 		    series[i].ChSel,
559 		    series[i].tx_power_cap,
560 		    series[i].RateFlags);
561 	}
562 }
563 #endif
564 
565 /*
566  * Setup the 11n rate scenario and burst duration for the given TX descriptor
567  * list.
568  *
569  * This isn't useful for sending beacon frames, which has different needs
570  * wrt what's passed into the rate scenario function.
571  */
572 void
573 ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
574     struct ath_buf *bf)
575 {
576 	HAL_11N_RATE_SERIES series[4];
577 	struct ath_desc *ds = bf->bf_desc;
578 	struct ath_hal *ah = sc->sc_ah;
579 	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
580 	int ctsrate = bf->bf_state.bfs_ctsrate;
581 	int flags = bf->bf_state.bfs_txflags;
582 
583 	/* Setup rate scenario */
584 	memset(&series, 0, sizeof(series));
585 
586 	ath_rateseries_setup(sc, ni, bf, series);
587 
588 #if 0
589 	ath_rateseries_print(sc, series);
590 #endif
591 
592 	/* Set rate scenario */
593 	/*
594 	 * Note: Don't allow hardware to override the duration on
595 	 * ps-poll packets.
596 	 */
597 	ath_hal_set11nratescenario(ah, ds,
598 	    !is_pspoll,	/* whether to override the duration or not */
599 	    ctsrate,	/* rts/cts rate */
600 	    series,	/* 11n rate series */
601 	    4,		/* number of series */
602 	    flags);
603 
604 	/* Set burst duration */
605 	/*
606 	 * This is only required when doing 11n burst, not aggregation
607 	 * ie, if there's a second frame in a RIFS or A-MPDU burst
608 	 * w/ >1 A-MPDU frame bursting back to back.
609 	 * Normal A-MPDU doesn't do bursting -between- aggregates.
610 	 *
611 	 * .. and it's highly likely this won't ever be implemented
612 	 */
613 	//ath_hal_set11nburstduration(ah, ds, 8192);
614 }
615 
616 /*
617  * Form an aggregate packet list.
618  *
619  * This function enforces the aggregate restrictions/requirements.
620  *
621  * These are:
622  *
623  * + The aggregate size maximum (64k for AR9160 and later, 8K for
624  *   AR5416 when doing RTS frame protection.)
625  * + Maximum number of sub-frames for an aggregate
626  * + The aggregate delimiter size, giving MACs time to do whatever is
627  *   needed before each frame
628  * + Enforce the BAW limit
629  *
630  * Each descriptor queued should have the DMA setup.
631  * The rate series, descriptor setup, linking, etc is all done
632  * externally. This routine simply chains them together.
633  * ath_tx_setds_11n() will take care of configuring the per-
634  * descriptor setup, and ath_buf_set_rate() will configure the
635  * rate control.
636  *
637  * The TID lock is required for the entirety of this function.
638  *
639  * If some code in another thread adds to the head of this
640  * list, very strange behaviour will occur. Since retransmission is the
641  * only reason this will occur, and this routine is designed to be called
642  * from within the scheduler task, it won't ever clash with the completion
643  * task.
644  *
645  * So if you want to call this from an upper layer context (eg, to direct-
646  * dispatch aggregate frames to the hardware), please keep this in mind.
647  */
648 ATH_AGGR_STATUS
649 ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
650     struct ath_tid *tid, ath_bufhead *bf_q)
651 {
652 	//struct ieee80211_node *ni = &an->an_node;
653 	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
654 	int nframes = 0;
655 	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
656 	struct ieee80211_tx_ampdu *tap;
657 	int status = ATH_AGGR_DONE;
658 	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
659 	int prev_al = 0;	/* XXX also for AR5416 burst */
660 
661 	ATH_TX_LOCK_ASSERT(sc);
662 
663 	tap = ath_tx_get_tx_tid(an, tid->tid);
664 	if (tap == NULL) {
665 		status = ATH_AGGR_ERROR;
666 		goto finish;
667 	}
668 
669 	h_baw = tap->txa_wnd / 2;
670 
671 	for (;;) {
672 		bf = ATH_TID_FIRST(tid);
673 		if (bf_first == NULL)
674 			bf_first = bf;
675 		if (bf == NULL) {
676 			status = ATH_AGGR_DONE;
677 			break;
678 		} else {
679 			/*
680 			 * It's the first frame;
681 			 * set the aggregation limit based on the
682 			 * rate control decision that has been made.
683 			 */
684 			aggr_limit = ath_get_aggr_limit(sc, bf_first);
685 		}
686 
687 		/* Set this early just so things don't get confused */
688 		bf->bf_next = NULL;
689 
690 		/*
691 		 * Don't unlock the tid lock until we're sure we are going
692 		 * to queue this frame.
693 		 */
694 
695 		/*
696 		 * If the frame doesn't have a sequence number that we're
697 		 * tracking in the BAW (eg NULL QOS data frame), we can't
698 		 * aggregate it. Stop the aggregation process; the sender
699 		 * can then TX what's in the list thus far and then
700 		 * TX the frame individually.
701 		 */
702 		if (! bf->bf_state.bfs_dobaw) {
703 			status = ATH_AGGR_NONAGGR;
704 			break;
705 		}
706 
707 		/*
708 		 * If any of the rates are non-HT, this packet
709 		 * can't be aggregated.
710 		 * XXX TODO: add a bf_state flag which gets marked
711 		 * if any active rate is non-HT.
712 		 */
713 
714 		/*
715 		 * do not exceed aggregation limit
716 		 */
717 		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
718 		if (nframes &&
719 		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
720 			status = ATH_AGGR_LIMITED;
721 			break;
722 		}
723 
724 		/*
725 		 * If RTS/CTS is set on the first frame, enforce
726 		 * the RTS aggregate limit.
727 		 */
728 		if (bf_first->bf_state.bfs_txflags &
729 		    (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
730 			if (nframes &&
731 			   (sc->sc_rts_aggr_limit <
732 			     (al + bpad + al_delta + prev_al))) {
733 				status = ATH_AGGR_8K_LIMITED;
734 				break;
735 			}
736 		}
737 
738 		/*
739 		 * Do not exceed subframe limit.
740 		 */
741 		if ((nframes + prev_frames) >= MIN((h_baw),
742 		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
743 			status = ATH_AGGR_LIMITED;
744 			break;
745 		}
746 
747 		/*
748 		 * If the current frame has an RTS/CTS configuration
749 		 * that differs from the first frame, override the
750 		 * subsequent frame with this config.
751 		 */
752 		bf->bf_state.bfs_txflags &=
753 		    ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
754 		bf->bf_state.bfs_txflags |=
755 		    bf_first->bf_state.bfs_txflags &
756 		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
757 
758 		/*
759 		 * If the packet has a sequence number, do not
760 		 * step outside of the block-ack window.
761 		 */
762 		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
763 		    SEQNO(bf->bf_state.bfs_seqno))) {
764 			status = ATH_AGGR_BAW_CLOSED;
765 			break;
766 		}
767 
768 		/*
769 		 * this packet is part of an aggregate.
770 		 */
771 		ATH_TID_REMOVE(tid, bf, bf_list);
772 
773 		/* The TID lock is required for the BAW update */
774 		ath_tx_addto_baw(sc, an, tid, bf);
775 		bf->bf_state.bfs_addedbaw = 1;
776 
777 		/*
778 		 * XXX enforce ACK for aggregate frames (this needs to be
779 		 * XXX handled more gracefully?
780 		 */
781 		if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
782 			device_printf(sc->sc_dev,
783 			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
784 			    __func__);
785 			bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
786 		}
787 
788 		/*
789 		 * Add the now owned buffer (which isn't
790 		 * on the software TXQ any longer) to our
791 		 * aggregate frame list.
792 		 */
793 		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
794 		nframes ++;
795 
796 		/* Completion handler */
797 		bf->bf_comp = ath_tx_aggr_comp;
798 
799 		/*
800 		 * add padding for previous frame to aggregation length
801 		 */
802 		al += bpad + al_delta;
803 
804 		/*
805 		 * Calculate delimiters needed for the current frame
806 		 */
807 		bf->bf_state.bfs_ndelim =
808 		    ath_compute_num_delims(sc, bf_first,
809 		    bf->bf_state.bfs_pktlen);
810 
811 		/*
812 		 * Calculate the padding needed from this set of delimiters,
813 		 * used when calculating if the next frame will fit in
814 		 * the aggregate.
815 		 */
816 		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
817 
818 		/*
819 		 * Chain the buffers together
820 		 */
821 		if (bf_prev)
822 			bf_prev->bf_next = bf;
823 		bf_prev = bf;
824 
825 		/*
826 		 * XXX TODO: if any sub-frames have RTS/CTS enabled;
827 		 * enable it for the entire aggregate.
828 		 */
829 
830 #if 0
831 		/*
832 		 * terminate aggregation on a small packet boundary
833 		 */
834 		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
835 			status = ATH_AGGR_SHORTPKT;
836 			break;
837 		}
838 #endif
839 
840 	}
841 
842 finish:
843 	/*
844 	 * Just in case the list was empty when we tried to
845 	 * dequeue a packet ..
846 	 */
847 	if (bf_first) {
848 		bf_first->bf_state.bfs_al = al;
849 		bf_first->bf_state.bfs_nframes = nframes;
850 	}
851 	return status;
852 }
853