if_ath_tx_ht.c revision 227364
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: head/sys/dev/ath/if_ath_tx_ht.c 227364 2011-11-08 22:43:13Z adrian $");
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#define	ATH_AGGR_ENCRYPTDELIM	10	/* number of delimiters for encryption padding */
102
103/*
104 * returns delimiter padding required given the packet length
105 */
106#define	ATH_AGGR_GET_NDELIM(_len)					\
107	    (((((_len) + ATH_AGGR_DELIM_SZ) < ATH_AGGR_MINPLEN) ?	\
108	    (ATH_AGGR_MINPLEN - (_len) - ATH_AGGR_DELIM_SZ) : 0) >> 2)
109
110#define	PADBYTES(_len)		((4 - ((_len) % 4)) % 4)
111
112int ath_max_4ms_framelen[4][32] = {
113	[MCS_HT20] = {
114		3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
115		6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
116		9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
117		12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
118	},
119	[MCS_HT20_SGI] = {
120		3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
121		7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
122		10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
123		14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
124	},
125	[MCS_HT40] = {
126		6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
127		13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
128		20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
129		26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
130	},
131	[MCS_HT40_SGI] = {
132		7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
133		14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
134		22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
135		29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
136	}
137};
138
139/*
140 * XXX should be in net80211
141 */
142static int ieee80211_mpdudensity_map[] = {
143	0,		/* IEEE80211_HTCAP_MPDUDENSITY_NA */
144	25,		/* IEEE80211_HTCAP_MPDUDENSITY_025 */
145	50,		/* IEEE80211_HTCAP_MPDUDENSITY_05 */
146	100,		/* IEEE80211_HTCAP_MPDUDENSITY_1 */
147	200,		/* IEEE80211_HTCAP_MPDUDENSITY_2 */
148	400,		/* IEEE80211_HTCAP_MPDUDENSITY_4 */
149	800,		/* IEEE80211_HTCAP_MPDUDENSITY_8 */
150	1600,		/* IEEE80211_HTCAP_MPDUDENSITY_16 */
151};
152
153/*
154 * XXX should be in the HAL/net80211 ?
155 */
156#define	BITS_PER_BYTE		8
157#define	OFDM_PLCP_BITS		22
158#define	HT_RC_2_MCS(_rc)	((_rc) & 0x7f)
159#define	HT_RC_2_STREAMS(_rc)	((((_rc) & 0x78) >> 3) + 1)
160#define	L_STF			8
161#define	L_LTF			8
162#define	L_SIG			4
163#define	HT_SIG			8
164#define	HT_STF			4
165#define	HT_LTF(_ns)		(4 * (_ns))
166#define	SYMBOL_TIME(_ns)	((_ns) << 2)		// ns * 4 us
167#define	SYMBOL_TIME_HALFGI(_ns)	(((_ns) * 18 + 4) / 5)	// ns * 3.6 us
168#define	NUM_SYMBOLS_PER_USEC(_usec)	(_usec >> 2)
169#define	NUM_SYMBOLS_PER_USEC_HALFGI(_usec)	(((_usec*5)-4)/18)
170#define	IS_HT_RATE(_rate)	((_rate) & 0x80)
171
172const uint32_t bits_per_symbol[][2] = {
173    /* 20MHz 40MHz */
174    {    26,   54 },     //  0: BPSK
175    {    52,  108 },     //  1: QPSK 1/2
176    {    78,  162 },     //  2: QPSK 3/4
177    {   104,  216 },     //  3: 16-QAM 1/2
178    {   156,  324 },     //  4: 16-QAM 3/4
179    {   208,  432 },     //  5: 64-QAM 2/3
180    {   234,  486 },     //  6: 64-QAM 3/4
181    {   260,  540 },     //  7: 64-QAM 5/6
182    {    52,  108 },     //  8: BPSK
183    {   104,  216 },     //  9: QPSK 1/2
184    {   156,  324 },     // 10: QPSK 3/4
185    {   208,  432 },     // 11: 16-QAM 1/2
186    {   312,  648 },     // 12: 16-QAM 3/4
187    {   416,  864 },     // 13: 64-QAM 2/3
188    {   468,  972 },     // 14: 64-QAM 3/4
189    {   520, 1080 },     // 15: 64-QAM 5/6
190    {    78,  162 },     // 16: BPSK
191    {   156,  324 },     // 17: QPSK 1/2
192    {   234,  486 },     // 18: QPSK 3/4
193    {   312,  648 },     // 19: 16-QAM 1/2
194    {   468,  972 },     // 20: 16-QAM 3/4
195    {   624, 1296 },     // 21: 64-QAM 2/3
196    {   702, 1458 },     // 22: 64-QAM 3/4
197    {   780, 1620 },     // 23: 64-QAM 5/6
198    {   104,  216 },     // 24: BPSK
199    {   208,  432 },     // 25: QPSK 1/2
200    {   312,  648 },     // 26: QPSK 3/4
201    {   416,  864 },     // 27: 16-QAM 1/2
202    {   624, 1296 },     // 28: 16-QAM 3/4
203    {   832, 1728 },     // 29: 64-QAM 2/3
204    {   936, 1944 },     // 30: 64-QAM 3/4
205    {  1040, 2160 },     // 31: 64-QAM 5/6
206};
207
208/*
209 * Fill in the rate array information based on the current
210 * node configuration and the choices made by the rate
211 * selection code and ath_buf setup code.
212 *
213 * Later on, this may end up also being made by the
214 * rate control code, but for now it can live here.
215 *
216 * This needs to be called just before the packet is
217 * queued to the software queue or hardware queue,
218 * so all of the needed fields in bf_state are setup.
219 */
220void
221ath_tx_rate_fill_rcflags(struct ath_softc *sc, struct ath_buf *bf)
222{
223	struct ieee80211_node *ni = bf->bf_node;
224	struct ieee80211com *ic = ni->ni_ic;
225	const HAL_RATE_TABLE *rt = sc->sc_currates;
226	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
227	uint8_t rate;
228	int i;
229
230	for (i = 0; i < ATH_RC_NUM; i++) {
231		rc[i].flags = 0;
232		if (rc[i].tries == 0)
233			continue;
234
235		rate = rt->info[rc[i].rix].rateCode;
236
237		/*
238		 * XXX only do this for legacy rates?
239		 */
240		if (bf->bf_state.bfs_shpream)
241			rate |= rt->info[rc[i].rix].shortPreamble;
242
243		/*
244		 * Save this, used by the TX and completion code
245		 */
246		rc[i].ratecode = rate;
247
248		if (bf->bf_state.bfs_flags &
249		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
250			rc[i].flags |= ATH_RC_RTSCTS_FLAG;
251
252		/* Only enable shortgi, 2040, dual-stream if HT is set */
253		if (IS_HT_RATE(rate)) {
254			rc[i].flags |= ATH_RC_HT_FLAG;
255
256			if (ni->ni_chw == 40)
257				rc[i].flags |= ATH_RC_CW40_FLAG;
258
259			if (ni->ni_chw == 40 &&
260			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
261			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
262				rc[i].flags |= ATH_RC_SGI_FLAG;
263
264			if (ni->ni_chw == 20 &&
265			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
266			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
267				rc[i].flags |= ATH_RC_SGI_FLAG;
268
269			/* XXX dual stream? and 3-stream? */
270		}
271
272		/*
273		 * Calculate the maximum 4ms frame length based
274		 * on the MCS rate, SGI and channel width flags.
275		 */
276		if ((rc[i].flags & ATH_RC_HT_FLAG) &&
277		    (HT_RC_2_MCS(rate) < 32)) {
278			int j;
279			if (rc[i].flags & ATH_RC_CW40_FLAG) {
280				if (rc[i].flags & ATH_RC_SGI_FLAG)
281					j = MCS_HT40_SGI;
282				else
283					j = MCS_HT40;
284			} else {
285				if (rc[i].flags & ATH_RC_SGI_FLAG)
286					j = MCS_HT20_SGI;
287				else
288					j = MCS_HT20;
289			}
290			rc[i].max4msframelen =
291			    ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
292		} else
293			rc[i].max4msframelen = 0;
294		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
295		    "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
296		    __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
297	}
298}
299
300/*
301 * Return the number of delimiters to be added to
302 * meet the minimum required mpdudensity.
303 *
304 * Caller should make sure that the rate is HT.
305 *
306 * TODO: is this delimiter calculation supposed to be the
307 * total frame length, the hdr length, the data length (including
308 * delimiters, padding, CRC, etc) or ?
309 *
310 * TODO: this should ensure that the rate control information
311 * HAS been setup for the first rate.
312 *
313 * TODO: ensure this is only called for MCS rates.
314 *
315 * TODO: enforce MCS < 31
316 */
317static int
318ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
319    uint16_t pktlen)
320{
321	const HAL_RATE_TABLE *rt = sc->sc_currates;
322	struct ieee80211_node *ni = first_bf->bf_node;
323	struct ieee80211vap *vap = ni->ni_vap;
324	int ndelim, mindelim = 0;
325	int mpdudensity;	 /* in 1/100'th of a microsecond */
326	uint8_t rc, rix, flags;
327	int width, half_gi;
328	uint32_t nsymbits, nsymbols;
329	uint16_t minlen;
330
331	/*
332	 * vap->iv_ampdu_density is a value, rather than the actual
333	 * density.
334	 */
335	if (vap->iv_ampdu_density > IEEE80211_HTCAP_MPDUDENSITY_16)
336		mpdudensity = 1600;		/* maximum density */
337	else
338		mpdudensity = ieee80211_mpdudensity_map[vap->iv_ampdu_density];
339
340	/* Select standard number of delimiters based on frame length */
341	ndelim = ATH_AGGR_GET_NDELIM(pktlen);
342
343	/*
344	 * If encryption is enabled, add extra delimiters to let the
345	 * crypto hardware catch up. This could be tuned per-MAC and
346	 * per-rate, but for now we'll simply assume encryption is
347	 * always enabled.
348	 */
349	ndelim += ATH_AGGR_ENCRYPTDELIM;
350
351	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
352	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
353	    __func__, pktlen, ndelim, mpdudensity);
354
355	/*
356	 * If the MPDU density is 0, we can return here.
357	 * Otherwise, we need to convert the desired mpdudensity
358	 * into a byte length, based on the rate in the subframe.
359	 */
360	if (mpdudensity == 0)
361		return ndelim;
362
363	/*
364	 * Convert desired mpdu density from microeconds to bytes based
365	 * on highest rate in rate series (i.e. first rate) to determine
366	 * required minimum length for subframe. Take into account
367	 * whether high rate is 20 or 40Mhz and half or full GI.
368	 */
369	rix = first_bf->bf_state.bfs_rc[0].rix;
370	rc = rt->info[rix].rateCode;
371	flags = first_bf->bf_state.bfs_rc[0].flags;
372	width = !! (flags & ATH_RC_CW40_FLAG);
373	half_gi = !! (flags & ATH_RC_SGI_FLAG);
374
375	/*
376	 * mpdudensity is in 1/100th of a usec, so divide by 100
377	 */
378	if (half_gi)
379		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
380	else
381		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
382	nsymbols /= 100;
383
384	if (nsymbols == 0)
385		nsymbols = 1;
386
387	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
388	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
389
390	/*
391	 * Min length is the minimum frame length for the
392	 * required MPDU density.
393	 */
394	if (pktlen < minlen) {
395		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
396		ndelim = MAX(mindelim, ndelim);
397	}
398
399	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
400	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
401	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
402
403	return ndelim;
404}
405
406/*
407 * Fetch the aggregation limit.
408 *
409 * It's the lowest of the four rate series 4ms frame length.
410 */
411static int
412ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
413{
414	int amin = 65530;
415	int i;
416
417	for (i = 0; i < 4; i++) {
418		if (bf->bf_state.bfs_rc[i].tries == 0)
419			continue;
420		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
421	}
422
423	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
424	    __func__, amin);
425
426	return amin;
427}
428
429/*
430 * Setup a 11n rate series structure
431 *
432 * This should be called for both legacy and MCS rates.
433 *
434 * It, along with ath_buf_set_rate, must be called -after- a burst
435 * or aggregate is setup.
436 */
437static void
438ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
439    struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
440{
441#define	HT_RC_2_STREAMS(_rc)	((((_rc) & 0x78) >> 3) + 1)
442	struct ieee80211com *ic = ni->ni_ic;
443	struct ath_hal *ah = sc->sc_ah;
444	HAL_BOOL shortPreamble = AH_FALSE;
445	const HAL_RATE_TABLE *rt = sc->sc_currates;
446	int i;
447	int pktlen;
448	int flags = bf->bf_state.bfs_flags;
449	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
450
451	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
452	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
453		shortPreamble = AH_TRUE;
454
455	/*
456	 * If this is the first frame in an aggregate series,
457	 * use the aggregate length.
458	 */
459	if (bf->bf_state.bfs_aggr)
460		pktlen = bf->bf_state.bfs_al;
461	else
462		pktlen = bf->bf_state.bfs_pktlen;
463
464	/*
465	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
466	 * XXX fields.
467	 */
468	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
469	for (i = 0; i < 4;  i++) {
470		/* Only set flags for actual TX attempts */
471		if (rc[i].tries == 0)
472			continue;
473
474		series[i].Tries = rc[i].tries;
475
476		/*
477		 * XXX this isn't strictly correct - sc_txchainmask
478		 * XXX isn't the currently active chainmask;
479		 * XXX it's the interface chainmask at startup.
480		 * XXX It's overridden in the HAL rate scenario function
481		 * XXX for now.
482		 */
483		series[i].ChSel = sc->sc_txchainmask;
484
485		if (flags & (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
486			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
487
488		/*
489		 * Transmit 40MHz frames only if the node has negotiated
490		 * it rather than whether the node is capable of it or not.
491	 	 * It's subtly different in the hostap case.
492	 	 */
493		if (ni->ni_chw == 40)
494			series[i].RateFlags |= HAL_RATESERIES_2040;
495
496		/*
497		 * Set short-GI only if the node has advertised it
498		 * the channel width is suitable, and we support it.
499		 * We don't currently have a "negotiated" set of bits -
500		 * ni_htcap is what the remote end sends, not what this
501		 * node is capable of.
502		 */
503		if (ni->ni_chw == 40 &&
504		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
505		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
506			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
507
508		if (ni->ni_chw == 20 &&
509		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
510		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
511			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
512
513		series[i].Rate = rt->info[rc[i].rix].rateCode;
514
515		/* PktDuration doesn't include slot, ACK, RTS, etc timing - it's just the packet duration */
516		if (series[i].Rate & IEEE80211_RATE_MCS) {
517			series[i].PktDuration =
518			    ath_computedur_ht(pktlen
519				, series[i].Rate
520				, HT_RC_2_STREAMS(series[i].Rate)
521				, series[i].RateFlags & HAL_RATESERIES_2040
522				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
523		} else {
524			if (shortPreamble)
525				series[i].Rate |=
526				    rt->info[rc[i].rix].shortPreamble;
527			series[i].PktDuration = ath_hal_computetxtime(ah,
528			    rt, pktlen, rc[i].rix, shortPreamble);
529		}
530	}
531#undef	HT_RC_2_STREAMS
532}
533
534#if 0
535static void
536ath_rateseries_print(HAL_11N_RATE_SERIES *series)
537{
538	int i;
539	for (i = 0; i < 4; i++) {
540		printf("series %d: rate %x; tries %d; pktDuration %d; chSel %d; rateFlags %x\n",
541		    i,
542		    series[i].Rate,
543		    series[i].Tries,
544		    series[i].PktDuration,
545		    series[i].ChSel,
546		    series[i].RateFlags);
547	}
548}
549#endif
550
551/*
552 * Setup the 11n rate scenario and burst duration for the given TX descriptor
553 * list.
554 *
555 * This isn't useful for sending beacon frames, which has different needs
556 * wrt what's passed into the rate scenario function.
557 */
558
559void
560ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
561    struct ath_buf *bf)
562{
563	HAL_11N_RATE_SERIES series[4];
564	struct ath_desc *ds = bf->bf_desc;
565	struct ath_desc *lastds = NULL;
566	struct ath_hal *ah = sc->sc_ah;
567	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
568	int ctsrate = bf->bf_state.bfs_ctsrate;
569	int flags = bf->bf_state.bfs_flags;
570
571	/* Setup rate scenario */
572	memset(&series, 0, sizeof(series));
573
574	ath_rateseries_setup(sc, ni, bf, series);
575
576	/* Enforce AR5416 aggregate limit - can't do RTS w/ an agg frame > 8k */
577
578	/* Enforce RTS and CTS are mutually exclusive */
579
580	/* Get a pointer to the last tx descriptor in the list */
581	lastds = bf->bf_lastds;
582
583#if 0
584	printf("pktlen: %d; flags 0x%x\n", pktlen, flags);
585	ath_rateseries_print(series);
586#endif
587
588	/* Set rate scenario */
589	ath_hal_set11nratescenario(ah, ds,
590	    !is_pspoll,	/* whether to override the duration or not */
591			/* don't allow hardware to override the duration on ps-poll packets */
592	    ctsrate,	/* rts/cts rate */
593	    series,	/* 11n rate series */
594	    4,		/* number of series */
595	    flags);
596
597	/* Setup the last descriptor in the chain */
598	ath_hal_setuplasttxdesc(ah, lastds, ds);
599
600	/* Set burst duration */
601	/*
602	 * This is only required when doing 11n burst, not aggregation
603	 * ie, if there's a second frame in a RIFS or A-MPDU burst
604	 * w/ >1 A-MPDU frame bursting back to back.
605	 * Normal A-MPDU doesn't do bursting -between- aggregates.
606	 *
607	 * .. and it's highly likely this won't ever be implemented
608	 */
609	//ath_hal_set11nburstduration(ah, ds, 8192);
610}
611
612/*
613 * Form an aggregate packet list.
614 *
615 * This function enforces the aggregate restrictions/requirements.
616 *
617 * These are:
618 *
619 * + The aggregate size maximum (64k for AR9160 and later, 8K for
620 *   AR5416 when doing RTS frame protection.)
621 * + Maximum number of sub-frames for an aggregate
622 * + The aggregate delimiter size, giving MACs time to do whatever is
623 *   needed before each frame
624 * + Enforce the BAW limit
625 *
626 * Each descriptor queued should have the DMA setup.
627 * The rate series, descriptor setup, linking, etc is all done
628 * externally. This routine simply chains them together.
629 * ath_tx_setds_11n() will take care of configuring the per-
630 * descriptor setup, and ath_buf_set_rate() will configure the
631 * rate control.
632 *
633 * Note that the TID lock is only grabbed when dequeuing packets from
634 * the TID queue. If some code in another thread adds to the head of this
635 * list, very strange behaviour will occur. Since retransmission is the
636 * only reason this will occur, and this routine is designed to be called
637 * from within the scheduler task, it won't ever clash with the completion
638 * task.
639 *
640 * So if you want to call this from an upper layer context (eg, to direct-
641 * dispatch aggregate frames to the hardware), please keep this in mind.
642 */
643ATH_AGGR_STATUS
644ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an, struct ath_tid *tid,
645    ath_bufhead *bf_q)
646{
647	//struct ieee80211_node *ni = &an->an_node;
648	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
649	int nframes = 0;
650	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
651	struct ieee80211_tx_ampdu *tap;
652	int status = ATH_AGGR_DONE;
653	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
654	int prev_al = 0;	/* XXX also for AR5416 burst */
655
656	ATH_TXQ_LOCK_ASSERT(sc->sc_ac2q[tid->ac]);
657
658	tap = ath_tx_get_tx_tid(an, tid->tid);
659	if (tap == NULL) {
660		status = ATH_AGGR_ERROR;
661		goto finish;
662	}
663
664	h_baw = tap->txa_wnd / 2;
665
666	for (;;) {
667		bf = TAILQ_FIRST(&tid->axq_q);
668		if (bf_first == NULL)
669			bf_first = bf;
670		if (bf == NULL) {
671			status = ATH_AGGR_DONE;
672			break;
673		} else {
674			/*
675			 * It's the first frame;
676			 * set the aggregation limit based on the
677			 * rate control decision that has been made.
678			 */
679			aggr_limit = ath_get_aggr_limit(sc, bf_first);
680		}
681
682		/* Set this early just so things don't get confused */
683		bf->bf_next = NULL;
684
685		/*
686		 * Don't unlock the tid lock until we're sure we are going
687		 * to queue this frame.
688		 */
689
690		/*
691		 * If the frame doesn't have a sequence number that we're
692		 * tracking in the BAW (eg NULL QOS data frame), we can't
693		 * aggregate it. Stop the aggregation process; the sender
694		 * can then TX what's in the list thus far and then
695		 * TX the frame individually.
696		 */
697		if (! bf->bf_state.bfs_dobaw) {
698			status = ATH_AGGR_NONAGGR;
699			break;
700		}
701
702		/*
703		 * If any of the rates are non-HT, this packet
704		 * can't be aggregated.
705		 * XXX TODO: add a bf_state flag which gets marked
706		 * if any active rate is non-HT.
707		 */
708
709		/*
710		 * If the packet has a sequence number, do not
711		 * step outside of the block-ack window.
712		 */
713		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
714		    SEQNO(bf->bf_state.bfs_seqno))) {
715		    status = ATH_AGGR_BAW_CLOSED;
716		    break;
717		}
718
719		/*
720		 * XXX TODO: AR5416 has an 8K aggregation size limit
721		 * when RTS is enabled, and RTS is required for dual-stream
722		 * rates.
723		 *
724		 * For now, limit all aggregates for the AR5416 to be 8K.
725		 */
726
727		/*
728		 * do not exceed aggregation limit
729		 */
730		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
731		if (nframes &&
732		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
733			status = ATH_AGGR_LIMITED;
734			break;
735		}
736
737		/*
738		 * Do not exceed subframe limit.
739		 */
740		if ((nframes + prev_frames) >= MIN((h_baw),
741		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
742			status = ATH_AGGR_LIMITED;
743			break;
744		}
745
746		/*
747		 * this packet is part of an aggregate.
748		 */
749		ATH_TXQ_REMOVE(tid, bf, bf_list);
750
751		/* The TID lock is required for the BAW update */
752		ath_tx_addto_baw(sc, an, tid, bf);
753		bf->bf_state.bfs_addedbaw = 1;
754
755		/*
756		 * XXX TODO: If any frame in the aggregate requires RTS/CTS,
757		 * set the first frame.
758		 */
759
760		/*
761		 * XXX enforce ACK for aggregate frames (this needs to be
762		 * XXX handled more gracefully?
763		 */
764		if (bf->bf_state.bfs_flags & HAL_TXDESC_NOACK) {
765			device_printf(sc->sc_dev,
766			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
767			    __func__);
768			bf->bf_state.bfs_flags &= (~HAL_TXDESC_NOACK);
769		}
770
771		/*
772		 * Add the now owned buffer (which isn't
773		 * on the software TXQ any longer) to our
774		 * aggregate frame list.
775		 */
776		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
777		nframes ++;
778
779		/* Completion handler */
780		bf->bf_comp = ath_tx_aggr_comp;
781
782		/*
783		 * add padding for previous frame to aggregation length
784		 */
785		al += bpad + al_delta;
786
787		/*
788		 * Calculate delimiters needed for the current frame
789		 */
790		bf->bf_state.bfs_ndelim =
791		    ath_compute_num_delims(sc, bf_first,
792		    bf->bf_state.bfs_pktlen);
793
794		/*
795		 * Calculate the padding needed from this set of delimiters,
796		 * used when calculating if the next frame will fit in
797		 * the aggregate.
798		 */
799		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
800
801		/*
802		 * Chain the buffers together
803		 */
804		if (bf_prev)
805			bf_prev->bf_next = bf;
806		bf_prev = bf;
807
808		/*
809		 * XXX TODO: if any sub-frames have RTS/CTS enabled;
810		 * enable it for the entire aggregate.
811		 */
812
813#if 0
814		/*
815		 * terminate aggregation on a small packet boundary
816		 */
817		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
818			status = ATH_AGGR_SHORTPKT;
819			break;
820		}
821#endif
822
823	}
824
825finish:
826	/*
827	 * Just in case the list was empty when we tried to
828	 * dequeue a packet ..
829	 */
830	if (bf_first) {
831		bf_first->bf_state.bfs_al = al;
832		bf_first->bf_state.bfs_nframes = nframes;
833	}
834	return status;
835}
836