xref: /freebsd/sys/dev/ath/if_ath_tx_ht.c (revision 74d9553e43cfafc29448d0bb836916aa21dea0de)
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 ieee80211vap *vap = ni->ni_vap;
226 	struct ieee80211com *ic = ni->ni_ic;
227 	const HAL_RATE_TABLE *rt = sc->sc_currates;
228 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
229 	uint8_t rate;
230 	int i;
231 	int do_ldpc;
232 	int do_stbc;
233 
234 	/*
235 	 * We only do LDPC if the rate is 11n, both we and the
236 	 * receiver support LDPC and it's enabled.
237 	 *
238 	 * It's a global flag, not a per-try flag, so we clear
239 	 * it if any of the rate entries aren't 11n.
240 	 */
241 	do_ldpc = 0;
242 	if ((ni->ni_vap->iv_flags_ht & IEEE80211_FHT_LDPC_TX) &&
243 	    (ni->ni_htcap & IEEE80211_HTCAP_LDPC))
244 		do_ldpc = 1;
245 
246 	/*
247 	 * The 11n duration calculation doesn't know about LDPC,
248 	 * so don't enable it for positioning.
249 	 */
250 	if (bf->bf_flags & ATH_BUF_TOA_PROBE)
251 		do_ldpc = 0;
252 
253 	do_stbc = 0;
254 
255 	for (i = 0; i < ATH_RC_NUM; i++) {
256 		rc[i].flags = 0;
257 		if (rc[i].tries == 0)
258 			continue;
259 
260 		rate = rt->info[rc[i].rix].rateCode;
261 
262 		/*
263 		 * Only enable short preamble for legacy rates
264 		 */
265 		if ((! IS_HT_RATE(rate)) && bf->bf_state.bfs_shpream)
266 			rate |= rt->info[rc[i].rix].shortPreamble;
267 
268 		/*
269 		 * Save this, used by the TX and completion code
270 		 */
271 		rc[i].ratecode = rate;
272 
273 		if (bf->bf_state.bfs_txflags &
274 		    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA))
275 			rc[i].flags |= ATH_RC_RTSCTS_FLAG;
276 
277 		/*
278 		 * If we can't do LDPC, don't.
279 		 */
280 		if (! IS_HT_RATE(rate))
281 			do_ldpc = 0;
282 
283 		/* Only enable shortgi, 2040, dual-stream if HT is set */
284 		if (IS_HT_RATE(rate)) {
285 			rc[i].flags |= ATH_RC_HT_FLAG;
286 
287 			if (ni->ni_chw == 40)
288 				rc[i].flags |= ATH_RC_CW40_FLAG;
289 
290 			/*
291 			 * NOTE: Don't do short-gi for positioning frames.
292 			 *
293 			 * For now, the ath_hal and net80211 HT duration
294 			 * calculation rounds up the 11n data txtime
295 			 * to the nearest multiple of 3.6 microseconds
296 			 * and doesn't return the fractional part, so
297 			 * we are always "out" by some amount.
298 			 */
299 			if (ni->ni_chw == 40 &&
300 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI40 &&
301 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI40 &&
302 			    vap->iv_flags_ht & IEEE80211_FHT_SHORTGI40 &&
303 			    (bf->bf_flags & ATH_BUF_TOA_PROBE) == 0) {
304 				rc[i].flags |= ATH_RC_SGI_FLAG;
305 			}
306 
307 			if (ni->ni_chw == 20 &&
308 			    ic->ic_htcaps & IEEE80211_HTCAP_SHORTGI20 &&
309 			    ni->ni_htcap & IEEE80211_HTCAP_SHORTGI20 &&
310 			    vap->iv_flags_ht & IEEE80211_FHT_SHORTGI20 &&
311 			    (bf->bf_flags & ATH_BUF_TOA_PROBE) == 0) {
312 				rc[i].flags |= ATH_RC_SGI_FLAG;
313 			}
314 
315 			/*
316 			 * If we have STBC TX enabled and the receiver
317 			 * can receive (at least) 1 stream STBC, AND it's
318 			 * MCS 0-7, AND we have at least two chains enabled,
319 			 * and we're not doing positioning, enable STBC.
320 			 */
321 			if (ic->ic_htcaps & IEEE80211_HTCAP_TXSTBC &&
322 			    (ni->ni_vap->iv_flags_ht & IEEE80211_FHT_STBC_TX) &&
323 			    (ni->ni_htcap & IEEE80211_HTCAP_RXSTBC) &&
324 			    (sc->sc_cur_txchainmask > 1) &&
325 			    (HT_RC_2_STREAMS(rate) == 1) &&
326 			    (bf->bf_flags & ATH_BUF_TOA_PROBE) == 0) {
327 				rc[i].flags |= ATH_RC_STBC_FLAG;
328 				do_stbc = 1;
329 			}
330 
331 			/*
332 			 * Dual / Triple stream rate?
333 			 */
334 			if (HT_RC_2_STREAMS(rate) == 2)
335 				rc[i].flags |= ATH_RC_DS_FLAG;
336 			else if (HT_RC_2_STREAMS(rate) == 3)
337 				rc[i].flags |= ATH_RC_TS_FLAG;
338 		}
339 
340 		/*
341 		 * Calculate the maximum TX power cap for the current
342 		 * node.
343 		 */
344 		rc[i].tx_power_cap = ieee80211_get_node_txpower(ni);
345 
346 		/*
347 		 * Calculate the maximum 4ms frame length based
348 		 * on the MCS rate, SGI and channel width flags.
349 		 */
350 		if ((rc[i].flags & ATH_RC_HT_FLAG) &&
351 		    (HT_RC_2_MCS(rate) < 32)) {
352 			int j;
353 			if (rc[i].flags & ATH_RC_CW40_FLAG) {
354 				if (rc[i].flags & ATH_RC_SGI_FLAG)
355 					j = MCS_HT40_SGI;
356 				else
357 					j = MCS_HT40;
358 			} else {
359 				if (rc[i].flags & ATH_RC_SGI_FLAG)
360 					j = MCS_HT20_SGI;
361 				else
362 					j = MCS_HT20;
363 			}
364 			rc[i].max4msframelen =
365 			    ath_max_4ms_framelen[j][HT_RC_2_MCS(rate)];
366 		} else
367 			rc[i].max4msframelen = 0;
368 		DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
369 		    "%s: i=%d, rate=0x%x, flags=0x%x, max4ms=%d\n",
370 		    __func__, i, rate, rc[i].flags, rc[i].max4msframelen);
371 	}
372 
373 	/*
374 	 * LDPC is a global flag, so ...
375 	 */
376 	if (do_ldpc) {
377 		bf->bf_state.bfs_txflags |= HAL_TXDESC_LDPC;
378 		sc->sc_stats.ast_tx_ldpc++;
379 	}
380 
381 	if (do_stbc) {
382 		sc->sc_stats.ast_tx_stbc++;
383 	}
384 }
385 
386 /*
387  * Return the number of delimiters to be added to
388  * meet the minimum required mpdudensity.
389  *
390  * Caller should make sure that the rate is HT.
391  *
392  * TODO: is this delimiter calculation supposed to be the
393  * total frame length, the hdr length, the data length (including
394  * delimiters, padding, CRC, etc) or ?
395  *
396  * TODO: this should ensure that the rate control information
397  * HAS been setup for the first rate.
398  *
399  * TODO: ensure this is only called for MCS rates.
400  *
401  * TODO: enforce MCS < 31
402  */
403 static int
404 ath_compute_num_delims(struct ath_softc *sc, struct ath_buf *first_bf,
405     uint16_t pktlen, int is_first)
406 {
407 #define	MS(_v, _f)	(((_v) & _f) >> _f##_S)
408 	const HAL_RATE_TABLE *rt = sc->sc_currates;
409 	struct ieee80211_node *ni = first_bf->bf_node;
410 	struct ieee80211vap *vap = ni->ni_vap;
411 	int ndelim, mindelim = 0;
412 	int mpdudensity;	/* in 1/100'th of a microsecond */
413 	int peer_mpdudensity;	/* net80211 value */
414 	uint8_t rc, rix, flags;
415 	int width, half_gi;
416 	uint32_t nsymbits, nsymbols;
417 	uint16_t minlen;
418 
419 	/*
420 	 * Get the advertised density from the node.
421 	 */
422 	peer_mpdudensity = MS(ni->ni_htparam, IEEE80211_HTCAP_MPDUDENSITY);
423 
424 	/*
425 	 * vap->iv_ampdu_density is a net80211 value, rather than the actual
426 	 * density.  Larger values are longer A-MPDU density spacing values,
427 	 * and we want to obey larger configured / negotiated density values
428 	 * per station if we get it.
429 	 */
430 	if (vap->iv_ampdu_density > peer_mpdudensity)
431 		peer_mpdudensity = vap->iv_ampdu_density;
432 
433 	/*
434 	 * Convert the A-MPDU density net80211 value to a 1/100 microsecond
435 	 * value for subsequent calculations.
436 	 */
437 	if (peer_mpdudensity > IEEE80211_HTCAP_MPDUDENSITY_16)
438 		mpdudensity = 1600;		/* maximum density */
439 	else
440 		mpdudensity = ieee80211_mpdudensity_map[peer_mpdudensity];
441 
442 	/* Select standard number of delimiters based on frame length */
443 	ndelim = ATH_AGGR_GET_NDELIM(pktlen);
444 
445 	/*
446 	 * If encryption is enabled, add extra delimiters to let the
447 	 * crypto hardware catch up. This could be tuned per-MAC and
448 	 * per-rate, but for now we'll simply assume encryption is
449 	 * always enabled.
450 	 *
451 	 * Also note that the Atheros reference driver inserts two
452 	 * delimiters by default for pre-AR9380 peers.  This will
453 	 * include "that" required delimiter.
454 	 */
455 	ndelim += ATH_AGGR_ENCRYPTDELIM;
456 
457 	/*
458 	 * For AR9380, there's a minimum number of delimeters
459 	 * required when doing RTS.
460 	 *
461 	 * XXX TODO: this is only needed if (a) RTS/CTS is enabled for
462 	 * this exchange, and (b) (done) this is the first sub-frame
463 	 * in the aggregate.
464 	 */
465 	if (sc->sc_use_ent && (sc->sc_ent_cfg & AH_ENT_RTSCTS_DELIM_WAR)
466 	    && ndelim < AH_FIRST_DESC_NDELIMS && is_first)
467 		ndelim = AH_FIRST_DESC_NDELIMS;
468 
469 	/*
470 	 * If sc_delim_min_pad is non-zero, enforce it as the minimum
471 	 * pad delimiter count.
472 	 */
473 	if (sc->sc_delim_min_pad != 0)
474 		ndelim = MAX(ndelim, sc->sc_delim_min_pad);
475 
476 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
477 	    "%s: pktlen=%d, ndelim=%d, mpdudensity=%d\n",
478 	    __func__, pktlen, ndelim, mpdudensity);
479 
480 	/*
481 	 * If the MPDU density is 0, we can return here.
482 	 * Otherwise, we need to convert the desired mpdudensity
483 	 * into a byte length, based on the rate in the subframe.
484 	 */
485 	if (mpdudensity == 0)
486 		return ndelim;
487 
488 	/*
489 	 * Convert desired mpdu density from microeconds to bytes based
490 	 * on highest rate in rate series (i.e. first rate) to determine
491 	 * required minimum length for subframe. Take into account
492 	 * whether high rate is 20 or 40Mhz and half or full GI.
493 	 */
494 	rix = first_bf->bf_state.bfs_rc[0].rix;
495 	rc = rt->info[rix].rateCode;
496 	flags = first_bf->bf_state.bfs_rc[0].flags;
497 	width = !! (flags & ATH_RC_CW40_FLAG);
498 	half_gi = !! (flags & ATH_RC_SGI_FLAG);
499 
500 	/*
501 	 * mpdudensity is in 1/100th of a usec, so divide by 100
502 	 */
503 	if (half_gi)
504 		nsymbols = NUM_SYMBOLS_PER_USEC_HALFGI(mpdudensity);
505 	else
506 		nsymbols = NUM_SYMBOLS_PER_USEC(mpdudensity);
507 	nsymbols /= 100;
508 
509 	if (nsymbols == 0)
510 		nsymbols = 1;
511 
512 	nsymbits = bits_per_symbol[HT_RC_2_MCS(rc)][width];
513 	minlen = (nsymbols * nsymbits) / BITS_PER_BYTE;
514 
515 	/*
516 	 * Min length is the minimum frame length for the
517 	 * required MPDU density.
518 	 */
519 	if (pktlen < minlen) {
520 		mindelim = (minlen - pktlen) / ATH_AGGR_DELIM_SZ;
521 		ndelim = MAX(mindelim, ndelim);
522 	}
523 
524 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
525 	    "%s: pktlen=%d, minlen=%d, rix=%x, rc=%x, width=%d, hgi=%d, ndelim=%d\n",
526 	    __func__, pktlen, minlen, rix, rc, width, half_gi, ndelim);
527 
528 	return ndelim;
529 #undef	MS
530 }
531 
532 /*
533  * XXX TODO: put into net80211
534  */
535 static int
536 ath_rx_ampdu_to_byte(char a)
537 {
538 	switch (a) {
539 	case IEEE80211_HTCAP_MAXRXAMPDU_16K:
540 		return 16384;
541 		break;
542 	case IEEE80211_HTCAP_MAXRXAMPDU_32K:
543 		return 32768;
544 		break;
545 	case IEEE80211_HTCAP_MAXRXAMPDU_64K:
546 		return 65536;
547 		break;
548 	case IEEE80211_HTCAP_MAXRXAMPDU_8K:
549 	default:
550 		return 8192;
551 		break;
552 	}
553 }
554 
555 /*
556  * Fetch the aggregation limit.
557  *
558  * It's the lowest of the four rate series 4ms frame length.
559  *
560  * Also take into account the hardware specific limits (8KiB on AR5416)
561  * and per-peer limits in non-STA mode.
562  */
563 static int
564 ath_get_aggr_limit(struct ath_softc *sc, struct ieee80211_node *ni,
565     struct ath_buf *bf)
566 {
567 	struct ieee80211vap *vap = ni->ni_vap;
568 
569 #define	MS(_v, _f)	(((_v) & _f) >> _f##_S)
570 	int amin = ATH_AGGR_MAXSIZE;
571 	int i;
572 
573 	/* Extract out the maximum configured driver A-MPDU limit */
574 	if (sc->sc_aggr_limit > 0 && sc->sc_aggr_limit < ATH_AGGR_MAXSIZE)
575 		amin = sc->sc_aggr_limit;
576 
577 	/* Check the vap configured transmit limit */
578 	amin = MIN(amin, ath_rx_ampdu_to_byte(vap->iv_ampdu_limit));
579 
580 	/*
581 	 * Check the HTCAP field for the maximum size the node has
582 	 * negotiated.  If it's smaller than what we have, cap it there.
583 	 */
584 	amin = MIN(amin, ath_rx_ampdu_to_byte(MS(ni->ni_htparam,
585 	    IEEE80211_HTCAP_MAXRXAMPDU)));
586 
587 	for (i = 0; i < ATH_RC_NUM; i++) {
588 		if (bf->bf_state.bfs_rc[i].tries == 0)
589 			continue;
590 		amin = MIN(amin, bf->bf_state.bfs_rc[i].max4msframelen);
591 	}
592 
593 	DPRINTF(sc, ATH_DEBUG_SW_TX_AGGR,
594 	    "%s: aggr_limit=%d, iv_ampdu_limit=%d, "
595 	    "peer maxrxampdu=%d, max frame len=%d\n",
596 	    __func__,
597 	    sc->sc_aggr_limit,
598 	    vap->iv_ampdu_limit,
599 	    MS(ni->ni_htparam, IEEE80211_HTCAP_MAXRXAMPDU),
600 	    amin);
601 
602 	return amin;
603 #undef	MS
604 }
605 
606 /*
607  * Setup a 11n rate series structure
608  *
609  * This should be called for both legacy and MCS rates.
610  *
611  * This uses the rate series stuf from ath_tx_rate_fill_rcflags().
612  *
613  * It, along with ath_buf_set_rate, must be called -after- a burst
614  * or aggregate is setup.
615  */
616 static void
617 ath_rateseries_setup(struct ath_softc *sc, struct ieee80211_node *ni,
618     struct ath_buf *bf, HAL_11N_RATE_SERIES *series)
619 {
620 	struct ieee80211com *ic = ni->ni_ic;
621 	struct ath_hal *ah = sc->sc_ah;
622 	HAL_BOOL shortPreamble = AH_FALSE;
623 	const HAL_RATE_TABLE *rt = sc->sc_currates;
624 	int i;
625 	int pktlen;
626 	struct ath_rc_series *rc = bf->bf_state.bfs_rc;
627 
628 	if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
629 	    (ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_PREAMBLE))
630 		shortPreamble = AH_TRUE;
631 
632 	/*
633 	 * If this is the first frame in an aggregate series,
634 	 * use the aggregate length.
635 	 */
636 	if (bf->bf_state.bfs_aggr)
637 		pktlen = bf->bf_state.bfs_al;
638 	else
639 		pktlen = bf->bf_state.bfs_pktlen;
640 
641 	/*
642 	 * XXX TODO: modify this routine to use the bfs_rc[x].flags
643 	 * XXX fields.
644 	 */
645 	memset(series, 0, sizeof(HAL_11N_RATE_SERIES) * 4);
646 	for (i = 0; i < ATH_RC_NUM;  i++) {
647 		/* Only set flags for actual TX attempts */
648 		if (rc[i].tries == 0)
649 			continue;
650 
651 		series[i].Tries = rc[i].tries;
652 
653 		/*
654 		 * XXX TODO: When the NIC is capable of three stream TX,
655 		 * transmit 1/2 stream rates on two streams.
656 		 *
657 		 * This reduces the power consumption of the NIC and
658 		 * keeps it within the PCIe slot power limits.
659 		 */
660 		series[i].ChSel = sc->sc_cur_txchainmask;
661 
662 		/*
663 		 * Setup rate and TX power cap for this series.
664 		 */
665 		series[i].Rate = rt->info[rc[i].rix].rateCode;
666 		series[i].RateIndex = rc[i].rix;
667 		series[i].tx_power_cap = rc[i].tx_power_cap;
668 
669 		/*
670 		 * Enable RTS/CTS as appropriate.
671 		 */
672 		if (rc[i].flags & ATH_RC_RTSCTS_FLAG)
673 			series[i].RateFlags |= HAL_RATESERIES_RTS_CTS;
674 
675 		/*
676 		 * 11n rate? Update 11n flags.
677 		 */
678 		if (rc[i].flags & ATH_RC_HT_FLAG) {
679 			if (rc[i].flags & ATH_RC_CW40_FLAG)
680 				series[i].RateFlags |= HAL_RATESERIES_2040;
681 
682 			if (rc[i].flags & ATH_RC_SGI_FLAG)
683 				series[i].RateFlags |= HAL_RATESERIES_HALFGI;
684 
685 			if (rc[i].flags & ATH_RC_STBC_FLAG)
686 				series[i].RateFlags |= HAL_RATESERIES_STBC;
687 		}
688 
689 		/*
690 		 * TODO: If we're all doing 11n rates then we can set LDPC.
691 		 * If we've been asked to /do/ LDPC but we are handed a
692 		 * legacy rate, then we should complain.  Loudly.
693 		 */
694 
695 		/*
696 		 * PktDuration doesn't include slot, ACK, RTS, etc timing -
697 		 * it's just the packet duration
698 		 */
699 		if (rc[i].flags & ATH_RC_HT_FLAG) {
700 			series[i].PktDuration =
701 			    ath_computedur_ht(pktlen
702 				, series[i].Rate
703 				, HT_RC_2_STREAMS(series[i].Rate)
704 				, series[i].RateFlags & HAL_RATESERIES_2040
705 				, series[i].RateFlags & HAL_RATESERIES_HALFGI);
706 		} else {
707 			if (shortPreamble)
708 				series[i].Rate |=
709 				    rt->info[rc[i].rix].shortPreamble;
710 			/* XXX TODO: don't include SIFS */
711 			series[i].PktDuration = ath_hal_computetxtime(ah,
712 			    rt, pktlen, rc[i].rix, shortPreamble, AH_TRUE);
713 		}
714 	}
715 }
716 
717 #ifdef	ATH_DEBUG
718 static void
719 ath_rateseries_print(struct ath_softc *sc, HAL_11N_RATE_SERIES *series)
720 {
721 	int i;
722 	for (i = 0; i < ATH_RC_NUM; i++) {
723 		device_printf(sc->sc_dev ,"series %d: rate %x; tries %d; "
724 		    "pktDuration %d; chSel %d; txpowcap %d, rateFlags %x\n",
725 		    i,
726 		    series[i].Rate,
727 		    series[i].Tries,
728 		    series[i].PktDuration,
729 		    series[i].ChSel,
730 		    series[i].tx_power_cap,
731 		    series[i].RateFlags);
732 	}
733 }
734 #endif
735 
736 /*
737  * Setup the 11n rate scenario and burst duration for the given TX descriptor
738  * list.
739  *
740  * This isn't useful for sending beacon frames, which has different needs
741  * wrt what's passed into the rate scenario function.
742  */
743 void
744 ath_buf_set_rate(struct ath_softc *sc, struct ieee80211_node *ni,
745     struct ath_buf *bf)
746 {
747 	HAL_11N_RATE_SERIES series[4];
748 	struct ath_desc *ds = bf->bf_desc;
749 	struct ath_hal *ah = sc->sc_ah;
750 	int is_pspoll = (bf->bf_state.bfs_atype == HAL_PKT_TYPE_PSPOLL);
751 	int ctsrate = bf->bf_state.bfs_ctsrate;
752 	int flags = bf->bf_state.bfs_txflags;
753 
754 	/* Setup rate scenario */
755 	memset(&series, 0, sizeof(series));
756 
757 	ath_rateseries_setup(sc, ni, bf, series);
758 
759 #ifdef	ATH_DEBUG
760 	if (sc->sc_debug & ATH_DEBUG_XMIT)
761 		ath_rateseries_print(sc, series);
762 #endif
763 
764 	/* Set rate scenario */
765 	/*
766 	 * Note: Don't allow hardware to override the duration on
767 	 * ps-poll packets.
768 	 */
769 	ath_hal_set11nratescenario(ah, ds,
770 	    !is_pspoll,	/* whether to override the duration or not */
771 	    ctsrate,	/* rts/cts rate */
772 	    series,	/* 11n rate series */
773 	    4,		/* number of series */
774 	    flags);
775 
776 	/* Set burst duration */
777 	/*
778 	 * This is only required when doing 11n burst, not aggregation
779 	 * ie, if there's a second frame in a RIFS or A-MPDU burst
780 	 * w/ >1 A-MPDU frame bursting back to back.
781 	 * Normal A-MPDU doesn't do bursting -between- aggregates.
782 	 *
783 	 * .. and it's highly likely this won't ever be implemented
784 	 */
785 	//ath_hal_set11nburstduration(ah, ds, 8192);
786 }
787 
788 /*
789  * Form an aggregate packet list.
790  *
791  * This function enforces the aggregate restrictions/requirements.
792  *
793  * These are:
794  *
795  * + The aggregate size maximum (64k for AR9160 and later, 8K for
796  *   AR5416 when doing RTS frame protection.)
797  * + Maximum number of sub-frames for an aggregate
798  * + The aggregate delimiter size, giving MACs time to do whatever is
799  *   needed before each frame
800  * + Enforce the BAW limit
801  *
802  * Each descriptor queued should have the DMA setup.
803  * The rate series, descriptor setup, linking, etc is all done
804  * externally. This routine simply chains them together.
805  * ath_tx_setds_11n() will take care of configuring the per-
806  * descriptor setup, and ath_buf_set_rate() will configure the
807  * rate control.
808  *
809  * The TID lock is required for the entirety of this function.
810  *
811  * If some code in another thread adds to the head of this
812  * list, very strange behaviour will occur. Since retransmission is the
813  * only reason this will occur, and this routine is designed to be called
814  * from within the scheduler task, it won't ever clash with the completion
815  * task.
816  *
817  * So if you want to call this from an upper layer context (eg, to direct-
818  * dispatch aggregate frames to the hardware), please keep this in mind.
819  */
820 ATH_AGGR_STATUS
821 ath_tx_form_aggr(struct ath_softc *sc, struct ath_node *an,
822     struct ath_tid *tid, ath_bufhead *bf_q)
823 {
824 	//struct ieee80211_node *ni = &an->an_node;
825 	struct ath_buf *bf, *bf_first = NULL, *bf_prev = NULL;
826 	int nframes = 0;
827 	uint16_t aggr_limit = 0, al = 0, bpad = 0, al_delta, h_baw;
828 	struct ieee80211_tx_ampdu *tap;
829 	int status = ATH_AGGR_DONE;
830 	int prev_frames = 0;	/* XXX for AR5416 burst, not done here */
831 	int prev_al = 0;	/* XXX also for AR5416 burst */
832 
833 	ATH_TX_LOCK_ASSERT(sc);
834 
835 	tap = ath_tx_get_tx_tid(an, tid->tid);
836 	if (tap == NULL) {
837 		status = ATH_AGGR_ERROR;
838 		goto finish;
839 	}
840 
841 	h_baw = tap->txa_wnd / 2;
842 
843 	for (;;) {
844 		bf = ATH_TID_FIRST(tid);
845 		if (bf_first == NULL)
846 			bf_first = bf;
847 		if (bf == NULL) {
848 			status = ATH_AGGR_DONE;
849 			break;
850 		} else {
851 			/*
852 			 * It's the first frame;
853 			 * set the aggregation limit based on the
854 			 * rate control decision that has been made.
855 			 */
856 			aggr_limit = ath_get_aggr_limit(sc, &an->an_node,
857 			    bf_first);
858 		}
859 
860 		/* Set this early just so things don't get confused */
861 		bf->bf_next = NULL;
862 
863 		/*
864 		 * If the frame doesn't have a sequence number that we're
865 		 * tracking in the BAW (eg NULL QOS data frame), we can't
866 		 * aggregate it. Stop the aggregation process; the sender
867 		 * can then TX what's in the list thus far and then
868 		 * TX the frame individually.
869 		 */
870 		if (! bf->bf_state.bfs_dobaw) {
871 			status = ATH_AGGR_NONAGGR;
872 			break;
873 		}
874 
875 		/*
876 		 * If any of the rates are non-HT, this packet
877 		 * can't be aggregated.
878 		 * XXX TODO: add a bf_state flag which gets marked
879 		 * if any active rate is non-HT.
880 		 */
881 
882 		/*
883 		 * do not exceed aggregation limit
884 		 */
885 		al_delta = ATH_AGGR_DELIM_SZ + bf->bf_state.bfs_pktlen;
886 		if (nframes &&
887 		    (aggr_limit < (al + bpad + al_delta + prev_al))) {
888 			status = ATH_AGGR_LIMITED;
889 			break;
890 		}
891 
892 		/*
893 		 * If RTS/CTS is set on the first frame, enforce
894 		 * the RTS aggregate limit.
895 		 */
896 		if (bf_first->bf_state.bfs_txflags &
897 		    (HAL_TXDESC_CTSENA | HAL_TXDESC_RTSENA)) {
898 			if (nframes &&
899 			   (sc->sc_rts_aggr_limit <
900 			     (al + bpad + al_delta + prev_al))) {
901 				status = ATH_AGGR_8K_LIMITED;
902 				break;
903 			}
904 		}
905 
906 		/*
907 		 * Do not exceed subframe limit.
908 		 */
909 		if ((nframes + prev_frames) >= MIN((h_baw),
910 		    IEEE80211_AMPDU_SUBFRAME_DEFAULT)) {
911 			status = ATH_AGGR_LIMITED;
912 			break;
913 		}
914 
915 		/*
916 		 * If the current frame has an RTS/CTS configuration
917 		 * that differs from the first frame, override the
918 		 * subsequent frame with this config.
919 		 */
920 		if (bf != bf_first) {
921 			bf->bf_state.bfs_txflags &=
922 			    ~ (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
923 			bf->bf_state.bfs_txflags |=
924 			    bf_first->bf_state.bfs_txflags &
925 			    (HAL_TXDESC_RTSENA | HAL_TXDESC_CTSENA);
926 		}
927 
928 		/*
929 		 * If the packet has a sequence number, do not
930 		 * step outside of the block-ack window.
931 		 */
932 		if (! BAW_WITHIN(tap->txa_start, tap->txa_wnd,
933 		    SEQNO(bf->bf_state.bfs_seqno))) {
934 			status = ATH_AGGR_BAW_CLOSED;
935 			break;
936 		}
937 
938 		/*
939 		 * this packet is part of an aggregate.
940 		 */
941 		ATH_TID_REMOVE(tid, bf, bf_list);
942 
943 		/* The TID lock is required for the BAW update */
944 		ath_tx_addto_baw(sc, an, tid, bf);
945 		bf->bf_state.bfs_addedbaw = 1;
946 
947 		/*
948 		 * XXX enforce ACK for aggregate frames (this needs to be
949 		 * XXX handled more gracefully?
950 		 */
951 		if (bf->bf_state.bfs_txflags & HAL_TXDESC_NOACK) {
952 			device_printf(sc->sc_dev,
953 			    "%s: HAL_TXDESC_NOACK set for an aggregate frame?\n",
954 			    __func__);
955 			bf->bf_state.bfs_txflags &= (~HAL_TXDESC_NOACK);
956 		}
957 
958 		/*
959 		 * Add the now owned buffer (which isn't
960 		 * on the software TXQ any longer) to our
961 		 * aggregate frame list.
962 		 */
963 		TAILQ_INSERT_TAIL(bf_q, bf, bf_list);
964 		nframes ++;
965 
966 		/* Completion handler */
967 		bf->bf_comp = ath_tx_aggr_comp;
968 
969 		/*
970 		 * add padding for previous frame to aggregation length
971 		 */
972 		al += bpad + al_delta;
973 
974 		/*
975 		 * Calculate delimiters needed for the current frame
976 		 */
977 		bf->bf_state.bfs_ndelim =
978 		    ath_compute_num_delims(sc, bf_first,
979 		    bf->bf_state.bfs_pktlen, (bf_first == bf));
980 
981 		/*
982 		 * Calculate the padding needed from this set of delimiters,
983 		 * used when calculating if the next frame will fit in
984 		 * the aggregate.
985 		 */
986 		bpad = PADBYTES(al_delta) + (bf->bf_state.bfs_ndelim << 2);
987 
988 		/*
989 		 * Chain the buffers together
990 		 */
991 		if (bf_prev)
992 			bf_prev->bf_next = bf;
993 		bf_prev = bf;
994 
995 		/*
996 		 * If we're leaking frames, just return at this point;
997 		 * we've queued a single frame and we don't want to add
998 		 * any more.
999 		 */
1000 		if (tid->an->an_leak_count) {
1001 			status = ATH_AGGR_LEAK_CLOSED;
1002 			break;
1003 		}
1004 
1005 #if 0
1006 		/*
1007 		 * terminate aggregation on a small packet boundary
1008 		 */
1009 		if (bf->bf_state.bfs_pktlen < ATH_AGGR_MINPLEN) {
1010 			status = ATH_AGGR_SHORTPKT;
1011 			break;
1012 		}
1013 #endif
1014 
1015 	}
1016 
1017 finish:
1018 	/*
1019 	 * Just in case the list was empty when we tried to
1020 	 * dequeue a packet ..
1021 	 */
1022 	if (bf_first) {
1023 		bf_first->bf_state.bfs_al = al;
1024 		bf_first->bf_state.bfs_nframes = nframes;
1025 	}
1026 	return status;
1027 }
1028