if_ath_tx_ht.c revision 247368
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 247368 2013-02-27 00:49:32Z 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/* 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
113int 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 */
143static 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
173const 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 */
221void
222ath_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 */
318static int
319ath_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	 * Also note that the Atheros reference driver inserts two
351	 * delimiters by default for pre-AR9380 peers.  This will
352	 * include "that" required delimiter.
353	 */
354	ndelim += ATH_AGGR_ENCRYPTDELIM;
355
356	/*
357	 * For AR9380, there's a minimum number of delimeters
358	 * required when doing RTS.
359	 *
360	 * XXX TODO: this is only needed if (a) RTS/CTS is enabled, and
361	 * XXX (b) this is the first sub-frame in the aggregate.
362	 */
363	if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
364	    && ndelim < AH_FIRST_DESC_NDELIMS)
365		ndelim = AH_FIRST_DESC_NDELIMS;
366
367	/*
368	 * If sc_delim_min_pad is non-zero, enforce it as the minimum
369	 * pad delimiter count.
370	 */
371	if (sc->sc_delim_min_pad != 0)
372		ndelim = MAX(ndelim, sc->sc_delim_min_pad);
373
374	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
375	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
376	    __func__, pktlen, ndelim, mpdudensity);
377
378	/*
379	 * If the MPDU density is 0, we can return here.
380	 * Otherwise, we need to convert the desired mpdudensity
381	 * into a byte length, based on the rate in the subframe.
382	 */
383	if (mpdudensity == 0)
384		return ndelim;
385
386	/*
387	 * Convert desired mpdu density from microeconds to bytes based
388	 * on highest rate in rate series (i.e. first rate) to determine
389	 * required minimum length for subframe. Take into account
390	 * whether high rate is 20 or 40Mhz and half or full GI.
391	 */
392	rix = first_bf->bf_state.bfs_rc[0].rix;
393	rc = rt->info[rix].rateCode;
394	flags = first_bf->bf_state.bfs_rc[0].flags;
395	width = !! (flags & ATH_RC_CW40_FLAG);
396	half_gi = !! (flags & ATH_RC_SGI_FLAG);
397
398	/*
399	 * mpdudensity is in 1/100th of a usec, so divide by 100
400	 */
401	if (half_gi)
402		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
403	else
404		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
405	nsymbols /= 100;
406
407	if (nsymbols == 0)
408		nsymbols = 1;
409
410	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
411	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
412
413	/*
414	 * Min length is the minimum frame length for the
415	 * required MPDU density.
416	 */
417	if (pktlen < minlen) {
418		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
419		ndelim = MAX(mindelim, ndelim);
420	}
421
422	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
423	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
424	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
425
426	return ndelim;
427}
428
429/*
430 * Fetch the aggregation limit.
431 *
432 * It's the lowest of the four rate series 4ms frame length.
433 */
434static int
435ath_get_aggr_limit(struct ath_softc *sc, struct ath_buf *bf)
436{
437	int amin = ATH_AGGR_MAXSIZE;
438	int i;
439
440	if (sc->sc_aggr_limit > 0 && sc->sc_aggr_limit < ATH_AGGR_MAXSIZE)
441		amin = sc->sc_aggr_limit;
442
443	for (i = 0; i < ATH_RC_NUM; i++) {
444		if (bf->bf_state.bfs_rc[i].tries == 0)
445			continue;
446		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
447	}
448
449	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR, "%s: max frame len= %d\n",
450	    __func__, amin);
451
452	return amin;
453}
454
455/*
456 * Setup a 11n rate series structure
457 *
458 * This should be called for both legacy and MCS rates.
459 *
460 * It, along with ath_buf_set_rate, must be called -after- a burst
461 * or aggregate is setup.
462 */
463static void
464ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
465    struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
466{
467	struct ieee80211com *ic = ni->ni_ic;
468	struct ath_hal *ah = sc->sc_ah;
469	HAL_BOOL shortPreamble = AH_FALSE;
470	const HAL_RATE_TABLE *rt = sc->sc_currates;
471	int i;
472	int pktlen;
473	int flags = bf->bf_state.bfs_txflags;
474	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
475
476	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
477	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
478		shortPreamble = AH_TRUE;
479
480	/*
481	 * If this is the first frame in an aggregate series,
482	 * use the aggregate length.
483	 */
484	if (bf->bf_state.bfs_aggr)
485		pktlen = bf->bf_state.bfs_al;
486	else
487		pktlen = bf->bf_state.bfs_pktlen;
488
489	/*
490	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
491	 * XXX fields.
492	 */
493	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
494	for (i = 0; i < ATH_RC_NUM;  i++) {
495		/* Only set flags for actual TX attempts */
496		if (rc[i].tries == 0)
497			continue;
498
499		series[i].Tries = rc[i].tries;
500
501		/*
502		 * XXX TODO: When the NIC is capable of three stream TX,
503		 * transmit 1/2 stream rates on two streams.
504		 *
505		 * This reduces the power consumption of the NIC and
506		 * keeps it within the PCIe slot power limits.
507		 */
508		series[i].ChSel = sc->sc_cur_txchainmask;
509
510		if (flags & (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
511			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
512
513		/*
514		 * Transmit 40MHz frames only if the node has negotiated
515		 * it rather than whether the node is capable of it or not.
516	 	 * It's subtly different in the hostap case.
517	 	 */
518		if (ni->ni_chw == 40)
519			series[i].RateFlags |= HAL_RATESERIES_2040;
520
521		/*
522		 * Set short-GI only if the node has advertised it
523		 * the channel width is suitable, and we support it.
524		 * We don't currently have a "negotiated" set of bits -
525		 * ni_htcap is what the remote end sends, not what this
526		 * node is capable of.
527		 */
528		if (ni->ni_chw == 40 &&
529		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
530		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40)
531			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
532
533		if (ni->ni_chw == 20 &&
534		    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
535		    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20)
536			series[i].RateFlags |= HAL_RATESERIES_HALFGI;
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 = 0x3f;	/* XXX for now */
544
545
546		/*
547		 * If we have STBC TX enabled and the receiver
548		 * can receive (at least) 1 stream STBC, AND it's
549		 * MCS 0-7, AND we have at least two chains enabled,
550		 * enable STBC.
551		 */
552		if (ic->ic_htcaps & IEEE80211_HTCAP_TXSTBC &&
553		    ni->ni_htcap & IEEE80211_HTCAP_RXSTBC_1STREAM &&
554		    (sc->sc_cur_txchainmask > 1) &&
555		    HT_RC_2_STREAMS(series[i].Rate) == 1) {
556			series[i].RateFlags |= HAL_RATESERIES_STBC;
557		}
558
559		/*
560		 * XXX TODO: LDPC if it's possible
561		 */
562
563		/*
564		 * PktDuration doesn't include slot, ACK, RTS, etc timing -
565		 * it's just the packet duration
566		 */
567		if (series[i].Rate & IEEE80211_RATE_MCS) {
568			series[i].PktDuration =
569			    ath_computedur_ht(pktlen
570				, series[i].Rate
571				, HT_RC_2_STREAMS(series[i].Rate)
572				, series[i].RateFlags & HAL_RATESERIES_2040
573				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
574		} else {
575			if (shortPreamble)
576				series[i].Rate |=
577				    rt->info[rc[i].rix].shortPreamble;
578			series[i].PktDuration = ath_hal_computetxtime(ah,
579			    rt, pktlen, rc[i].rix, shortPreamble);
580		}
581	}
582}
583
584#if 0
585static void
586ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
587{
588	int i;
589	for (i = 0; i < ATH_RC_NUM; i++) {
590		device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
591		    "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
592		    i,
593		    series[i].Rate,
594		    series[i].Tries,
595		    series[i].PktDuration,
596		    series[i].ChSel,
597		    series[i].tx_power_cap,
598		    series[i].RateFlags);
599	}
600}
601#endif
602
603/*
604 * Setup the 11n rate scenario and burst duration for the given TX descriptor
605 * list.
606 *
607 * This isn't useful for sending beacon frames, which has different needs
608 * wrt what's passed into the rate scenario function.
609 */
610void
611ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
612    struct ath_buf *bf)
613{
614	HAL_11N_RATE_SERIES series[4];
615	struct ath_desc *ds = bf->bf_desc;
616	struct ath_hal *ah = sc->sc_ah;
617	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
618	int ctsrate = bf->bf_state.bfs_ctsrate;
619	int flags = bf->bf_state.bfs_txflags;
620
621	/* Setup rate scenario */
622	memset(&series, 0, sizeof(series));
623
624	ath_rateseries_setup(sc, ni, bf, series);
625
626#if 0
627	ath_rateseries_print(sc, series);
628#endif
629
630	/* Set rate scenario */
631	/*
632	 * Note: Don't allow hardware to override the duration on
633	 * ps-poll packets.
634	 */
635	ath_hal_set11nratescenario(ah, ds,
636	    !is_pspoll,	/* whether to override the duration or not */
637	    ctsrate,	/* rts/cts rate */
638	    series,	/* 11n rate series */
639	    4,		/* number of series */
640	    flags);
641
642	/* Set burst duration */
643	/*
644	 * This is only required when doing 11n burst, not aggregation
645	 * ie, if there's a second frame in a RIFS or A-MPDU burst
646	 * w/ >1 A-MPDU frame bursting back to back.
647	 * Normal A-MPDU doesn't do bursting -between- aggregates.
648	 *
649	 * .. and it's highly likely this won't ever be implemented
650	 */
651	//ath_hal_set11nburstduration(ah, ds, 8192);
652}
653
654/*
655 * Form an aggregate packet list.
656 *
657 * This function enforces the aggregate restrictions/requirements.
658 *
659 * These are:
660 *
661 * + The aggregate size maximum (64k for AR9160 and later, 8K for
662 *   AR5416 when doing RTS frame protection.)
663 * + Maximum number of sub-frames for an aggregate
664 * + The aggregate delimiter size, giving MACs time to do whatever is
665 *   needed before each frame
666 * + Enforce the BAW limit
667 *
668 * Each descriptor queued should have the DMA setup.
669 * The rate series, descriptor setup, linking, etc is all done
670 * externally. This routine simply chains them together.
671 * ath_tx_setds_11n() will take care of configuring the per-
672 * descriptor setup, and ath_buf_set_rate() will configure the
673 * rate control.
674 *
675 * The TID lock is required for the entirety of this function.
676 *
677 * If some code in another thread adds to the head of this
678 * list, very strange behaviour will occur. Since retransmission is the
679 * only reason this will occur, and this routine is designed to be called
680 * from within the scheduler task, it won't ever clash with the completion
681 * task.
682 *
683 * So if you want to call this from an upper layer context (eg, to direct-
684 * dispatch aggregate frames to the hardware), please keep this in mind.
685 */
686ATH_AGGR_STATUS
687ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
688    struct ath_tid *tid, ath_bufhead *bf_q)
689{
690	//struct ieee80211_node *ni = &an->an_node;
691	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
692	int nframes = 0;
693	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
694	struct ieee80211_tx_ampdu *tap;
695	int status = ATH_AGGR_DONE;
696	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
697	int prev_al = 0;	/* XXX also for AR5416 burst */
698
699	ATH_TX_LOCK_ASSERT(sc);
700
701	tap = ath_tx_get_tx_tid(an, tid->tid);
702	if (tap == NULL) {
703		status = ATH_AGGR_ERROR;
704		goto finish;
705	}
706
707	h_baw = tap->txa_wnd / 2;
708
709	for (;;) {
710		bf = ATH_TID_FIRST(tid);
711		if (bf_first == NULL)
712			bf_first = bf;
713		if (bf == NULL) {
714			status = ATH_AGGR_DONE;
715			break;
716		} else {
717			/*
718			 * It's the first frame;
719			 * set the aggregation limit based on the
720			 * rate control decision that has been made.
721			 */
722			aggr_limit = ath_get_aggr_limit(sc, bf_first);
723		}
724
725		/* Set this early just so things don't get confused */
726		bf->bf_next = NULL;
727
728		/*
729		 * If the frame doesn't have a sequence number that we're
730		 * tracking in the BAW (eg NULL QOS data frame), we can't
731		 * aggregate it. Stop the aggregation process; the sender
732		 * can then TX what's in the list thus far and then
733		 * TX the frame individually.
734		 */
735		if (! bf->bf_state.bfs_dobaw) {
736			status = ATH_AGGR_NONAGGR;
737			break;
738		}
739
740		/*
741		 * If any of the rates are non-HT, this packet
742		 * can't be aggregated.
743		 * XXX TODO: add a bf_state flag which gets marked
744		 * if any active rate is non-HT.
745		 */
746
747		/*
748		 * do not exceed aggregation limit
749		 */
750		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
751		if (nframes &&
752		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
753			status = ATH_AGGR_LIMITED;
754			break;
755		}
756
757		/*
758		 * If RTS/CTS is set on the first frame, enforce
759		 * the RTS aggregate limit.
760		 */
761		if (bf_first->bf_state.bfs_txflags &
762		    (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
763			if (nframes &&
764			   (sc->sc_rts_aggr_limit <
765			     (al + bpad + al_delta + prev_al))) {
766				status = ATH_AGGR_8K_LIMITED;
767				break;
768			}
769		}
770
771		/*
772		 * Do not exceed subframe limit.
773		 */
774		if ((nframes + prev_frames) >= MIN((h_baw),
775		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
776			status = ATH_AGGR_LIMITED;
777			break;
778		}
779
780		/*
781		 * If the current frame has an RTS/CTS configuration
782		 * that differs from the first frame, override the
783		 * subsequent frame with this config.
784		 */
785		if (bf != bf_first) {
786			bf->bf_state.bfs_txflags &=
787			    ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
788			bf->bf_state.bfs_txflags |=
789			    bf_first->bf_state.bfs_txflags &
790			    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
791		}
792
793		/*
794		 * If the packet has a sequence number, do not
795		 * step outside of the block-ack window.
796		 */
797		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
798		    SEQNO(bf->bf_state.bfs_seqno))) {
799			status = ATH_AGGR_BAW_CLOSED;
800			break;
801		}
802
803		/*
804		 * this packet is part of an aggregate.
805		 */
806		ATH_TID_REMOVE(tid, bf, bf_list);
807
808		/* The TID lock is required for the BAW update */
809		ath_tx_addto_baw(sc, an, tid, bf);
810		bf->bf_state.bfs_addedbaw = 1;
811
812		/*
813		 * XXX enforce ACK for aggregate frames (this needs to be
814		 * XXX handled more gracefully?
815		 */
816		if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
817			device_printf(sc->sc_dev,
818			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
819			    __func__);
820			bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
821		}
822
823		/*
824		 * Add the now owned buffer (which isn't
825		 * on the software TXQ any longer) to our
826		 * aggregate frame list.
827		 */
828		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
829		nframes ++;
830
831		/* Completion handler */
832		bf->bf_comp = ath_tx_aggr_comp;
833
834		/*
835		 * add padding for previous frame to aggregation length
836		 */
837		al += bpad + al_delta;
838
839		/*
840		 * Calculate delimiters needed for the current frame
841		 */
842		bf->bf_state.bfs_ndelim =
843		    ath_compute_num_delims(sc, bf_first,
844		    bf->bf_state.bfs_pktlen);
845
846		/*
847		 * Calculate the padding needed from this set of delimiters,
848		 * used when calculating if the next frame will fit in
849		 * the aggregate.
850		 */
851		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
852
853		/*
854		 * Chain the buffers together
855		 */
856		if (bf_prev)
857			bf_prev->bf_next = bf;
858		bf_prev = bf;
859
860		/*
861		 * XXX TODO: if any sub-frames have RTS/CTS enabled;
862		 * enable it for the entire aggregate.
863		 */
864
865#if 0
866		/*
867		 * terminate aggregation on a small packet boundary
868		 */
869		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
870			status = ATH_AGGR_SHORTPKT;
871			break;
872		}
873#endif
874
875	}
876
877finish:
878	/*
879	 * Just in case the list was empty when we tried to
880	 * dequeue a packet ..
881	 */
882	if (bf_first) {
883		bf_first->bf_state.bfs_al = al;
884		bf_first->bf_state.bfs_nframes = nframes;
885	}
886	return status;
887}
888