Implement basic 802.11n awareness in the PHY and AMRR rate control code.

* Add 802.11n 2ghz and 5ghz tables, including legacy rates and up to
  MCS23 rates (3x3.)

* Populate the rate code -> rate index lookup table with MCS _and_
  normal rates, but _not_ the basic rate flag.  Since the basic rate flag
  is the same as the MCS flag, we can only use one.

* Introduce some accessor inlines that do PLCP and rate table lookup/access
  and enforce that it doesn't set the basic rate bit.  They're not
  designed for MCS rates, so it will panic.

* Start converting drivers that use the rate table stuff to use the
  accessor inlines and strip the basic flag.

* Teach AMRR about basic 11n - it's still as crap for MCS as it is
  being used by iwn, so it's not a step _backwardS_.

* Convert iwn over to accept 11n MCS rates rather than 'translate' legacy
  to MCS rates.  It doesn't use a lookup table any longer; instead it's a
  function which takes the current node (for HT parameters) and the
  rate code, and returns the hardware PLCP code to use.

Tested:

* ath - it's a no-op, and it works that way
* iwn - both 11n and non-11n

3 files changed, 315 insertions, 30 deletions

diff --git a/sys/net80211/ieee80211_amrr.c b/sys/net80211/ieee80211_amrr.c
index 73dd901..874659f 100644
--- a/sys/net80211/ieee80211_amrr.c
+++ b/sys/net80211/ieee80211_amrr.c
@@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
 #endif
 
 #include <net80211/ieee80211_var.h>
+#include <net80211/ieee80211_ht.h>
 #include <net80211/ieee80211_amrr.h>
 #include <net80211/ieee80211_ratectl.h>
 
@@ -128,13 +129,25 @@ amrr_deinit(struct ieee80211vap *vap)
 	free(vap->iv_rs, M_80211_RATECTL);
 }
 
+static int
+amrr_node_is_11n(struct ieee80211_node *ni)
+{
+
+	if (ni->ni_chan == NULL)
+		return (0);
+	if (ni->ni_chan == IEEE80211_CHAN_ANYC)
+		return (0);
+	return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
+}
+
 static void
 amrr_node_init(struct ieee80211_node *ni)
 {
-	const struct ieee80211_rateset *rs = &ni->ni_rates;
+	const struct ieee80211_rateset *rs = NULL;
 	struct ieee80211vap *vap = ni->ni_vap;
 	struct ieee80211_amrr *amrr = vap->iv_rs;
 	struct ieee80211_amrr_node *amn;
+	uint8_t rate;
 
 	if (ni->ni_rctls == NULL) {
 		ni->ni_rctls = amn = malloc(sizeof(struct ieee80211_amrr_node),
@@ -152,16 +165,50 @@ amrr_node_init(struct ieee80211_node *ni)
 	amn->amn_txcnt = amn->amn_retrycnt = 0;
 	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
 
-	/* pick initial rate */
-	for (amn->amn_rix = rs->rs_nrates - 1;
-	     amn->amn_rix > 0 && (rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) > 72;
-	     amn->amn_rix--)
-		;
-	ni->ni_txrate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
+	/* 11n or not? Pick the right rateset */
+	if (amrr_node_is_11n(ni)) {
+		/* XXX ew */
+		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+		    "%s: 11n node", __func__);
+		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
+	} else {
+		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+		    "%s: non-11n node", __func__);
+		rs = &ni->ni_rates;
+	}
+
+	/* Initial rate - lowest */
+	rate = rs->rs_rates[0];
+
+	/* XXX clear the basic rate flag if it's not 11n */
+	if (! amrr_node_is_11n(ni))
+		rate &= IEEE80211_RATE_VAL;
+
+	/* pick initial rate from the rateset - HT or otherwise */
+	for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
+	    amn->amn_rix--) {
+		/* legacy - anything < 36mbit, stop searching */
+		/* 11n - stop at MCS4 / MCS12 / MCS28 */
+		if (amrr_node_is_11n(ni) &&
+		    (rs->rs_rates[amn->amn_rix] & 0x7) < 4)
+			break;
+		else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
+			break;
+		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
+	}
+
+	/* if the rate is an 11n rate, ensure the MCS bit is set */
+	if (amrr_node_is_11n(ni))
+		rate |= IEEE80211_RATE_MCS;
+
+	/* Assign initial rate from the rateset */
+	ni->ni_txrate = rate;
 	amn->amn_ticks = ticks;
 
 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
-	    "AMRR initial rate %d", ni->ni_txrate);
+	    "AMRR: nrates=%d, initial rate %d",
+	    rs->rs_nrates,
+	    rate);
 }
 
 static void
@@ -175,19 +222,34 @@ amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
     struct ieee80211_node *ni)
 {
 	int rix = amn->amn_rix;
+	const struct ieee80211_rateset *rs = NULL;
 
 	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
 
+	/* 11n or not? Pick the right rateset */
+	if (amrr_node_is_11n(ni)) {
+		/* XXX ew */
+		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
+	} else {
+		rs = &ni->ni_rates;
+	}
+
+	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
+	    "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
+	    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
+	    amn->amn_txcnt,
+	    amn->amn_retrycnt);
+
 	if (is_success(amn)) {
 		amn->amn_success++;
 		if (amn->amn_success >= amn->amn_success_threshold &&
-		    rix + 1 < ni->ni_rates.rs_nrates) {
+		    rix + 1 < rs->rs_nrates) {
 			amn->amn_recovery = 1;
 			amn->amn_success = 0;
 			rix++;
 			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
 			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
-			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
+			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
 			    amn->amn_txcnt, amn->amn_retrycnt);
 		} else {
 			amn->amn_recovery = 0;
@@ -208,7 +270,7 @@ amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
 			rix--;
 			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
 			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
-			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
+			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
 			    amn->amn_txcnt, amn->amn_retrycnt);
 		}
 		amn->amn_recovery = 0;
@@ -231,14 +293,27 @@ amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
 {
 	struct ieee80211_amrr_node *amn = ni->ni_rctls;
 	struct ieee80211_amrr *amrr = amn->amn_amrr;
+	const struct ieee80211_rateset *rs = NULL;
 	int rix;
 
+	/* 11n or not? Pick the right rateset */
+	if (amrr_node_is_11n(ni)) {
+		/* XXX ew */
+		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
+	} else {
+		rs = &ni->ni_rates;
+	}
+
 	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
 		rix = amrr_update(amrr, amn, ni);
 		if (rix != amn->amn_rix) {
 			/* update public rate */
-			ni->ni_txrate =
-			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
+			ni->ni_txrate = rs->rs_rates[rix];
+			/* XXX strip basic rate flag from txrate, if non-11n */
+			if (amrr_node_is_11n(ni))
+				ni->ni_txrate |= IEEE80211_RATE_MCS;
+			else
+				ni->ni_txrate &= IEEE80211_RATE_VAL;
 			amn->amn_rix = rix;
 		}
 		amn->amn_ticks = ticks;
diff --git a/sys/net80211/ieee80211_phy.c b/sys/net80211/ieee80211_phy.c
index d2ad60d..d1924d8 100644
--- a/sys/net80211/ieee80211_phy.c
+++ b/sys/net80211/ieee80211_phy.c
@@ -60,8 +60,11 @@ struct ieee80211_ds_plcp_hdr {
 #define	TURBO	IEEE80211_T_TURBO
 #define	HALF	IEEE80211_T_OFDM_HALF
 #define	QUART	IEEE80211_T_OFDM_QUARTER
+#define	HT	IEEE80211_T_HT
+/* XXX the 11n and the basic rate flag are unfortunately overlapping. Grr. */
+#define	N(r)	(IEEE80211_RATE_MCS | r)
 #define	PBCC	(IEEE80211_T_OFDM_QUARTER+1)		/* XXX */
-#define	B(r)	(0x80 | r)
+#define	B(r)	(IEEE80211_RATE_BASIC | r)
 #define	Mb(x)	(x*1000)
 
 static struct ieee80211_rate_table ieee80211_11b_table = {
@@ -176,6 +179,98 @@ static struct ieee80211_rate_table ieee80211_turboa_table = {
     },
 };
 
+static struct ieee80211_rate_table ieee80211_11ng_table = {
+    .rateCount = 36,
+    .info = {
+/*                                   short            ctrl  */
+/*                                Preamble  dot11Rate Rate */
+     [0] = { .phy = CCK,     1000,    0x00,      B(2),   0 },
+     [1] = { .phy = CCK,     2000,    0x04,      B(4),   1 },
+     [2] = { .phy = CCK,     5500,    0x04,     B(11),   2 },
+     [3] = { .phy = CCK,    11000,    0x04,     B(22),   3 },
+     [4] = { .phy = OFDM,    6000,    0x00,        12,   4 },
+     [5] = { .phy = OFDM,    9000,    0x00,        18,   4 },
+     [6] = { .phy = OFDM,   12000,    0x00,        24,   6 },
+     [7] = { .phy = OFDM,   18000,    0x00,        36,   6 },
+     [8] = { .phy = OFDM,   24000,    0x00,        48,   8 },
+     [9] = { .phy = OFDM,   36000,    0x00,        72,   8 },
+    [10] = { .phy = OFDM,   48000,    0x00,        96,   8 },
+    [11] = { .phy = OFDM,   54000,    0x00,       108,   8 },
+
+    [12] = { .phy = HT,      6500,    0x00,      N(0),   4 },
+    [13] = { .phy = HT,     13000,    0x00,      N(1),   6 },
+    [14] = { .phy = HT,     19500,    0x00,      N(2),   6 },
+    [15] = { .phy = HT,     26000,    0x00,      N(3),   8 },
+    [16] = { .phy = HT,     39000,    0x00,      N(4),   8 },
+    [17] = { .phy = HT,     52000,    0x00,      N(5),   8 },
+    [18] = { .phy = HT,     58500,    0x00,      N(6),   8 },
+    [19] = { .phy = HT,     65000,    0x00,      N(7),   8 },
+
+    [20] = { .phy = HT,     13000,    0x00,      N(8),   4 },
+    [21] = { .phy = HT,     26000,    0x00,      N(9),   6 },
+    [22] = { .phy = HT,     39000,    0x00,     N(10),   6 },
+    [23] = { .phy = HT,     52000,    0x00,     N(11),   8 },
+    [24] = { .phy = HT,     78000,    0x00,     N(12),   8 },
+    [25] = { .phy = HT,    104000,    0x00,     N(13),   8 },
+    [26] = { .phy = HT,    117000,    0x00,     N(14),   8 },
+    [27] = { .phy = HT,    130000,    0x00,     N(15),   8 },
+
+    [28] = { .phy = HT,     19500,    0x00,     N(16),   4 },
+    [29] = { .phy = HT,     39000,    0x00,     N(17),   6 },
+    [30] = { .phy = HT,     58500,    0x00,     N(18),   6 },
+    [31] = { .phy = HT,     78000,    0x00,     N(19),   8 },
+    [32] = { .phy = HT,    117000,    0x00,     N(20),   8 },
+    [33] = { .phy = HT,    156000,    0x00,     N(21),   8 },
+    [34] = { .phy = HT,    175500,    0x00,     N(22),   8 },
+    [35] = { .phy = HT,    195000,    0x00,     N(23),   8 },
+
+    },
+};
+
+static struct ieee80211_rate_table ieee80211_11na_table = {
+    .rateCount = 32,
+    .info = {
+/*                                   short            ctrl  */
+/*                                Preamble  dot11Rate Rate */
+     [0] = { .phy = OFDM,    6000,    0x00,     B(12),   0 },
+     [1] = { .phy = OFDM,    9000,    0x00,        18,   0 },
+     [2] = { .phy = OFDM,   12000,    0x00,     B(24),   2 },
+     [3] = { .phy = OFDM,   18000,    0x00,        36,   2 },
+     [4] = { .phy = OFDM,   24000,    0x00,     B(48),   4 },
+     [5] = { .phy = OFDM,   36000,    0x00,        72,   4 },
+     [6] = { .phy = OFDM,   48000,    0x00,        96,   4 },
+     [7] = { .phy = OFDM,   54000,    0x00,       108,   4 },
+
+     [8] = { .phy = HT,      6500,    0x00,      N(0),   0 },
+     [9] = { .phy = HT,     13000,    0x00,      N(1),   2 },
+    [10] = { .phy = HT,     19500,    0x00,      N(2),   2 },
+    [11] = { .phy = HT,     26000,    0x00,      N(3),   4 },
+    [12] = { .phy = HT,     39000,    0x00,      N(4),   4 },
+    [13] = { .phy = HT,     52000,    0x00,      N(5),   4 },
+    [14] = { .phy = HT,     58500,    0x00,      N(6),   4 },
+    [15] = { .phy = HT,     65000,    0x00,      N(7),   4 },
+
+    [16] = { .phy = HT,     13000,    0x00,      N(8),   0 },
+    [17] = { .phy = HT,     26000,    0x00,      N(9),   2 },
+    [18] = { .phy = HT,     39000,    0x00,     N(10),   2 },
+    [19] = { .phy = HT,     52000,    0x00,     N(11),   4 },
+    [20] = { .phy = HT,     78000,    0x00,     N(12),   4 },
+    [21] = { .phy = HT,    104000,    0x00,     N(13),   4 },
+    [22] = { .phy = HT,    117000,    0x00,     N(14),   4 },
+    [23] = { .phy = HT,    130000,    0x00,     N(15),   4 },
+
+    [24] = { .phy = HT,     19500,    0x00,     N(16),   0 },
+    [25] = { .phy = HT,     39000,    0x00,     N(17),   2 },
+    [26] = { .phy = HT,     58500,    0x00,     N(18),   2 },
+    [27] = { .phy = HT,     78000,    0x00,     N(19),   4 },
+    [28] = { .phy = HT,    117000,    0x00,     N(20),   4 },
+    [29] = { .phy = HT,    156000,    0x00,     N(21),   4 },
+    [30] = { .phy = HT,    175500,    0x00,     N(22),   4 },
+    [31] = { .phy = HT,    195000,    0x00,     N(23),   4 },
+
+    },
+};
+
 #undef	Mb
 #undef	B
 #undef	OFDM
@@ -184,6 +279,8 @@ static struct ieee80211_rate_table ieee80211_turboa_table = {
 #undef	CCK
 #undef	TURBO
 #undef	XR
+#undef	HT
+#undef	N
 
 /*
  * Setup a rate table's reverse lookup table and fill in
@@ -210,15 +307,23 @@ ieee80211_setup_ratetable(struct ieee80211_rate_table *rt)
 		uint8_t cix = rt->info[i].ctlRateIndex;
 		uint8_t ctl_rate = rt->info[cix].dot11Rate;
 
-		rt->rateCodeToIndex[code] = i;
-		if (code & IEEE80211_RATE_BASIC) {
-			/*
-			 * Map w/o basic rate bit too.
-			 */
-			code &= IEEE80211_RATE_VAL;
-			rt->rateCodeToIndex[code] = i;
+		/*
+		 * Map without the basic rate bit.
+		 *
+		 * It's up to the caller to ensure that the basic
+		 * rate bit is stripped here.
+		 *
+		 * For HT, use the MCS rate bit.
+		 */
+		code &= IEEE80211_RATE_VAL;
+		if (rt->info[i].phy == IEEE80211_T_HT) {
+			code |= IEEE80211_RATE_MCS;
 		}
 
+		/* XXX assume the control rate is non-MCS? */
+		ctl_rate &= IEEE80211_RATE_VAL;
+		rt->rateCodeToIndex[code] = i;
+
 		/*
 		 * XXX for 11g the control rate to use for 5.5 and 11 Mb/s
 		 *     depends on whether they are marked as basic rates;
@@ -247,11 +352,10 @@ ieee80211_phy_init(void)
 	static struct ieee80211_rate_table * const ratetables[] = {
 		&ieee80211_half_table,
 		&ieee80211_quarter_table,
-		&ieee80211_11a_table,
-		&ieee80211_11g_table,
+		&ieee80211_11na_table,
+		&ieee80211_11ng_table,
 		&ieee80211_turbog_table,
 		&ieee80211_turboa_table,
-		&ieee80211_turboa_table,
 		&ieee80211_11a_table,
 		&ieee80211_11g_table,
 		&ieee80211_11b_table
@@ -276,9 +380,9 @@ ieee80211_get_ratetable(struct ieee80211_channel *c)
 	else if (IEEE80211_IS_CHAN_QUARTER(c))
 		rt = &ieee80211_quarter_table;
 	else if (IEEE80211_IS_CHAN_HTA(c))
-		rt = &ieee80211_11a_table;	/* XXX */
+		rt = &ieee80211_11na_table;
 	else if (IEEE80211_IS_CHAN_HTG(c))
-		rt = &ieee80211_11g_table;	/* XXX */
+		rt = &ieee80211_11ng_table;
 	else if (IEEE80211_IS_CHAN_108G(c))
 		rt = &ieee80211_turbog_table;
 	else if (IEEE80211_IS_CHAN_ST(c))
@@ -463,3 +567,66 @@ ieee80211_compute_duration(const struct ieee80211_rate_table *rt,
 	}
 	return txTime;
 }
+
+static const uint16_t ht20_bps[32] = {
+	26, 52, 78, 104, 156, 208, 234, 260,
+	52, 104, 156, 208, 312, 416, 468, 520,
+	78, 156, 234, 312, 468, 624, 702, 780,
+	104, 208, 312, 416, 624, 832, 936, 1040
+};
+static const uint16_t ht40_bps[32] = {
+	54, 108, 162, 216, 324, 432, 486, 540,
+	108, 216, 324, 432, 648, 864, 972, 1080,
+	162, 324, 486, 648, 972, 1296, 1458, 1620,
+	216, 432, 648, 864, 1296, 1728, 1944, 2160
+};
+
+
+#define	OFDM_PLCP_BITS	22
+#define	HT_L_STF	8
+#define	HT_L_LTF	8
+#define	HT_L_SIG	4
+#define	HT_SIG		8
+#define	HT_STF		4
+#define	HT_LTF(n)	((n) * 4)
+
+#define	HT_RC_2_MCS(_rc)	((_rc) & 0xf)
+#define	HT_RC_2_STREAMS(_rc)	((((_rc) & 0x78) >> 3) + 1)
+#define	IS_HT_RATE(_rc)		( (_rc) & IEEE80211_RATE_MCS)
+
+/*
+ * Calculate the transmit duration of an 11n frame.
+ */
+uint32_t
+ieee80211_compute_duration_ht(uint32_t frameLen, uint16_t rate,
+    int streams, int isht40, int isShortGI)
+{
+	uint32_t bitsPerSymbol, numBits, numSymbols, txTime;
+
+	KASSERT(rate & IEEE80211_RATE_MCS, ("not mcs %d", rate));
+	KASSERT((rate &~ IEEE80211_RATE_MCS) < 31, ("bad mcs 0x%x", rate));
+
+	if (isht40)
+		bitsPerSymbol = ht40_bps[rate & 0x1f];
+	else
+		bitsPerSymbol = ht20_bps[rate & 0x1f];
+	numBits = OFDM_PLCP_BITS + (frameLen << 3);
+	numSymbols = howmany(numBits, bitsPerSymbol);
+	if (isShortGI)
+		txTime = ((numSymbols * 18) + 4) / 5;   /* 3.6us */
+	else
+		txTime = numSymbols * 4;                /* 4us */
+	return txTime + HT_L_STF + HT_L_LTF +
+	    HT_L_SIG + HT_SIG + HT_STF + HT_LTF(streams);
+}
+
+#undef	IS_HT_RATE
+#undef	HT_RC_2_STREAMS
+#undef	HT_RC_2_MCS
+#undef	HT_LTF
+#undef	HT_STF
+#undef	HT_SIG
+#undef	HT_L_SIG
+#undef	HT_L_LTF
+#undef	HT_L_STF
+#undef	OFDM_PLCP_BITS
diff --git a/sys/net80211/ieee80211_phy.h b/sys/net80211/ieee80211_phy.h
index 56b404f7..bf39cdd 100644
--- a/sys/net80211/ieee80211_phy.h
+++ b/sys/net80211/ieee80211_phy.h
@@ -60,6 +60,8 @@
 
 struct ieee80211_channel;
 
+#define	IEEE80211_RATE_TABLE_SIZE	128
+
 struct ieee80211_rate_table {
 	int		rateCount;		/* NB: for proper padding */
 	uint8_t		rateCodeToIndex[256];	/* back mapping */
@@ -74,7 +76,7 @@ struct ieee80211_rate_table {
 						 * rate; used for dur. calcs */
 		uint16_t	lpAckDuration;	/* long preamble ACK dur. */
 		uint16_t	spAckDuration;	/* short preamble ACK dur. */
-	} info[32];
+	} info[IEEE80211_RATE_TABLE_SIZE];
 };
 
 const struct ieee80211_rate_table *ieee80211_get_ratetable(
@@ -83,7 +85,14 @@ const struct ieee80211_rate_table *ieee80211_get_ratetable(
 static __inline__ uint8_t
 ieee80211_ack_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
 {
-	uint8_t cix = rt->info[rt->rateCodeToIndex[rate]].ctlRateIndex;
+	/*
+	 * XXX Assert this is for a legacy rate; not for an MCS rate.
+	 * If the caller wishes to use it for a basic rate, they should
+	 * clear the high bit first.
+	 */
+	KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
+
+	uint8_t cix = rt->info[rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]].ctlRateIndex;
 	KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
 	return rt->info[cix].dot11Rate;
 }
@@ -91,7 +100,14 @@ ieee80211_ack_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
 static __inline__ uint8_t
 ieee80211_ctl_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
 {
-	uint8_t cix = rt->info[rt->rateCodeToIndex[rate]].ctlRateIndex;
+	/*
+	 * XXX Assert this is for a legacy rate; not for an MCS rate.
+	 * If the caller wishes to use it for a basic rate, they should
+	 * clear the high bit first.
+	 */
+	KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
+
+	uint8_t cix = rt->info[rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]].ctlRateIndex;
 	KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
 	return rt->info[cix].dot11Rate;
 }
@@ -99,7 +115,14 @@ ieee80211_ctl_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
 static __inline__ enum ieee80211_phytype
 ieee80211_rate2phytype(const struct ieee80211_rate_table *rt, uint8_t rate)
 {
-	uint8_t rix = rt->rateCodeToIndex[rate];
+	/*
+	 * XXX Assert this is for a legacy rate; not for an MCS rate.
+	 * If the caller wishes to use it for a basic rate, they should
+	 * clear the high bit first.
+	 */
+	KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
+
+	uint8_t rix = rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL];
 	KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate));
 	return rt->info[rix].phy;
 }
@@ -107,6 +130,13 @@ ieee80211_rate2phytype(const struct ieee80211_rate_table *rt, uint8_t rate)
 static __inline__ int
 ieee80211_isratevalid(const struct ieee80211_rate_table *rt, uint8_t rate)
 {
+	/*
+	 * XXX Assert this is for a legacy rate; not for an MCS rate.
+	 * If the caller wishes to use it for a basic rate, they should
+	 * clear the high bit first.
+	 */
+	KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
+
 	return rt->rateCodeToIndex[rate] != (uint8_t)-1;
 }
 
@@ -134,6 +164,14 @@ ieee80211_ack_duration(const struct ieee80211_rate_table *rt,
 	}
 }
 
+static __inline__ uint8_t
+ieee80211_legacy_rate_lookup(const struct ieee80211_rate_table *rt,
+    uint8_t rate)
+{
+
+	return (rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]);
+}
+
 /*
  * Compute the time to transmit a frame of length frameLen bytes
  * using the specified 802.11 rate code, phy, and short preamble
@@ -151,5 +189,10 @@ uint8_t		ieee80211_plcp2rate(uint8_t, enum ieee80211_phytype);
  * Convert 802.11 rate code to PLCP signal.
  */
 uint8_t		ieee80211_rate2plcp(int, enum ieee80211_phytype);
+
+uint32_t	ieee80211_compute_duration_ht(uint32_t frameLen,
+			uint16_t rate, int streams, int isht40,
+			int isShortGI);
+
 #endif	/* _KERNEL */
 #endif	/* !_NET80211_IEEE80211_PHY_H_ */