mac80211: Import airtime calculation code from mt76

Felix recently added code to calculate airtime of packets to the mt76
driver. Import this into mac80211 so we can use it for airtime queue limit
calculations.

The airtime.c file is copied verbatim from the mt76 driver, and adjusted to
be usable in mac80211. This involves:

- Switching to mac80211 data structures.
- Adding support for 160 MHz channels and HE mode.
- Moving the symbol and duration calculations around a bit to avoid
  rounding with the higher rates and longer symbol times used for HE rates.

The per-rate TX rate calculation is also split out to its own function so
it can be used directly for the AQL calculations later.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20191119060610.76681-3-kyan@google.com
[fix HE_GROUP_IDX() to use 3 * bw, since there are 3 _gi values]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 603 insertions, 1 deletions

diff --git a/net/mac80211/Makefile b/net/mac80211/Makefile
index 4f03ebe732fa..6cbb1286d6c0 100644
--- a/net/mac80211/Makefile
+++ b/net/mac80211/Makefile
@@ -32,7 +32,8 @@ mac80211-y := \
 	chan.o \
 	trace.o mlme.o \
 	tdls.o \
-	ocb.o
+	ocb.o \
+	airtime.o
 
 mac80211-$(CONFIG_MAC80211_LEDS) += led.o
 mac80211-$(CONFIG_MAC80211_DEBUGFS) += \
diff --git a/net/mac80211/airtime.c b/net/mac80211/airtime.c
new file mode 100644
index 000000000000..63cb0028b02d
--- /dev/null
+++ b/net/mac80211/airtime.c
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: ISC
+/*
+ * Copyright (C) 2019 Felix Fietkau <nbd@nbd.name>
+ */
+
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+#include "sta_info.h"
+
+#define AVG_PKT_SIZE	1024
+
+/* Number of bits for an average sized packet */
+#define MCS_NBITS (AVG_PKT_SIZE << 3)
+
+/* Number of kilo-symbols (symbols * 1024) for a packet with (bps) bits per
+ * symbol. We use k-symbols to avoid rounding in the _TIME macros below.
+ */
+#define MCS_N_KSYMS(bps) DIV_ROUND_UP(MCS_NBITS << 10, (bps))
+
+/* Transmission time (in 1024 * usec) for a packet containing (ksyms) * 1024
+ * symbols.
+ */
+#define MCS_SYMBOL_TIME(sgi, ksyms)					\
+	(sgi ?								\
+	  ((ksyms) * 4 * 18) / 20 :		/* 3.6 us per sym */	\
+	  ((ksyms) * 4)			/* 4.0 us per sym */	\
+	)
+
+/* Transmit duration for the raw data part of an average sized packet */
+#define MCS_DURATION(streams, sgi, bps) \
+	((u32)MCS_SYMBOL_TIME(sgi, MCS_N_KSYMS((streams) * (bps))))
+
+#define MCS_DURATION_S(shift, streams, sgi, bps)		\
+	((u16)((MCS_DURATION(streams, sgi, bps) >> shift)))
+
+/* These should match the values in enum nl80211_he_gi */
+#define HE_GI_08 0
+#define HE_GI_16 1
+#define HE_GI_32 2
+
+/* Transmission time (1024 usec) for a packet containing (ksyms) * k-symbols */
+#define HE_SYMBOL_TIME(gi, ksyms)					\
+	(gi == HE_GI_08 ?						\
+	 ((ksyms) * 16 * 17) / 20 :		/* 13.6 us per sym */	\
+	 (gi == HE_GI_16 ?						\
+	  ((ksyms) * 16 * 18) / 20 :		/* 14.4 us per sym */	\
+	  ((ksyms) * 16)			/* 16.0 us per sym */	\
+	 ))
+
+/* Transmit duration for the raw data part of an average sized packet */
+#define HE_DURATION(streams, gi, bps) \
+	((u32)HE_SYMBOL_TIME(gi, MCS_N_KSYMS((streams) * (bps))))
+
+#define HE_DURATION_S(shift, streams, gi, bps)		\
+	(HE_DURATION(streams, gi, bps) >> shift)
+
+#define BW_20			0
+#define BW_40			1
+#define BW_80			2
+#define BW_160			3
+
+/*
+ * Define group sort order: HT40 -> SGI -> #streams
+ */
+#define IEEE80211_MAX_STREAMS		4
+#define IEEE80211_HT_STREAM_GROUPS	4 /* BW(=2) * SGI(=2) */
+#define IEEE80211_VHT_STREAM_GROUPS	8 /* BW(=4) * SGI(=2) */
+
+#define IEEE80211_HE_MAX_STREAMS	8
+#define IEEE80211_HE_STREAM_GROUPS	12 /* BW(=4) * GI(=3) */
+
+#define IEEE80211_HT_GROUPS_NB	(IEEE80211_MAX_STREAMS *	\
+				 IEEE80211_HT_STREAM_GROUPS)
+#define IEEE80211_VHT_GROUPS_NB	(IEEE80211_MAX_STREAMS *	\
+					 IEEE80211_VHT_STREAM_GROUPS)
+#define IEEE80211_HE_GROUPS_NB	(IEEE80211_HE_MAX_STREAMS *	\
+				 IEEE80211_HE_STREAM_GROUPS)
+#define IEEE80211_GROUPS_NB	(IEEE80211_HT_GROUPS_NB +	\
+				 IEEE80211_VHT_GROUPS_NB +	\
+				 IEEE80211_HE_GROUPS_NB)
+
+#define IEEE80211_HT_GROUP_0	0
+#define IEEE80211_VHT_GROUP_0	(IEEE80211_HT_GROUP_0 + IEEE80211_HT_GROUPS_NB)
+#define IEEE80211_HE_GROUP_0	(IEEE80211_VHT_GROUP_0 + IEEE80211_VHT_GROUPS_NB)
+
+#define MCS_GROUP_RATES		12
+
+#define HT_GROUP_IDX(_streams, _sgi, _ht40)	\
+	IEEE80211_HT_GROUP_0 +			\
+	IEEE80211_MAX_STREAMS * 2 * _ht40 +	\
+	IEEE80211_MAX_STREAMS * _sgi +		\
+	_streams - 1
+
+#define _MAX(a, b) (((a)>(b))?(a):(b))
+
+#define GROUP_SHIFT(duration)						\
+	_MAX(0, 16 - __builtin_clz(duration))
+
+/* MCS rate information for an MCS group */
+#define __MCS_GROUP(_streams, _sgi, _ht40, _s)				\
+	[HT_GROUP_IDX(_streams, _sgi, _ht40)] = {			\
+	.shift = _s,							\
+	.duration = {							\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 54 : 26),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 108 : 52),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 162 : 78),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 216 : 104),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 324 : 156),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 432 : 208),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 486 : 234),	\
+		MCS_DURATION_S(_s, _streams, _sgi, _ht40 ? 540 : 260)	\
+	}								\
+}
+
+#define MCS_GROUP_SHIFT(_streams, _sgi, _ht40)				\
+	GROUP_SHIFT(MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26))
+
+#define MCS_GROUP(_streams, _sgi, _ht40)				\
+	__MCS_GROUP(_streams, _sgi, _ht40,				\
+		    MCS_GROUP_SHIFT(_streams, _sgi, _ht40))
+
+#define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
+	(IEEE80211_VHT_GROUP_0 +					\
+	 IEEE80211_MAX_STREAMS * 2 * (_bw) +				\
+	 IEEE80211_MAX_STREAMS * (_sgi) +				\
+	 (_streams) - 1)
+
+#define BW2VBPS(_bw, r4, r3, r2, r1)					\
+	(_bw == BW_160 ? r4 : _bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
+
+#define __VHT_GROUP(_streams, _sgi, _bw, _s)				\
+	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
+	.shift = _s,							\
+	.duration = {							\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw,  234,  117,  54,  26)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw,  468,  234, 108,  52)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw,  702,  351, 162,  78)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw,  936,  468, 216, 104)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 1404,  702, 324, 156)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 1872,  936, 432, 208)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 2106, 1053, 486, 234)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 2340, 1170, 540, 260)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 2808, 1404, 648, 312)),	\
+		MCS_DURATION_S(_s, _streams, _sgi,			\
+			       BW2VBPS(_bw, 3120, 1560, 720, 346))	\
+        }								\
+}
+
+#define VHT_GROUP_SHIFT(_streams, _sgi, _bw)				\
+	GROUP_SHIFT(MCS_DURATION(_streams, _sgi,			\
+				 BW2VBPS(_bw, 243, 117,  54,  26)))
+
+#define VHT_GROUP(_streams, _sgi, _bw)					\
+	__VHT_GROUP(_streams, _sgi, _bw,				\
+		    VHT_GROUP_SHIFT(_streams, _sgi, _bw))
+
+
+#define HE_GROUP_IDX(_streams, _gi, _bw)				\
+	(IEEE80211_HE_GROUP_0 +					\
+	 IEEE80211_HE_MAX_STREAMS * 3 * (_bw) +			\
+	 IEEE80211_HE_MAX_STREAMS * (_gi) +				\
+	 (_streams) - 1)
+
+#define __HE_GROUP(_streams, _gi, _bw, _s)				\
+	[HE_GROUP_IDX(_streams, _gi, _bw)] = {			\
+	.shift = _s,							\
+	.duration = {							\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,   979,  489,  230,  115)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  1958,  979,  475,  230)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  2937, 1468,  705,  345)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  3916, 1958,  936,  475)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  5875, 2937, 1411,  705)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  7833, 3916, 1872,  936)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  8827, 4406, 2102, 1051)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw,  9806, 4896, 2347, 1166)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw, 11764, 5875, 2808, 1411)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw, 13060, 6523, 3124, 1555)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw, 14702, 7344, 3513, 1756)),	\
+		HE_DURATION_S(_s, _streams, _gi,			\
+			      BW2VBPS(_bw, 16329, 8164, 3902, 1944))	\
+        }								\
+}
+
+#define HE_GROUP_SHIFT(_streams, _gi, _bw)				\
+	GROUP_SHIFT(HE_DURATION(_streams, _gi,			\
+				BW2VBPS(_bw,   979,  489,  230,  115)))
+
+#define HE_GROUP(_streams, _gi, _bw)					\
+	__HE_GROUP(_streams, _gi, _bw,				\
+		   HE_GROUP_SHIFT(_streams, _gi, _bw))
+struct mcs_group {
+	u8 shift;
+	u16 duration[MCS_GROUP_RATES];
+};
+
+static const struct mcs_group airtime_mcs_groups[] = {
+	MCS_GROUP(1, 0, BW_20),
+	MCS_GROUP(2, 0, BW_20),
+	MCS_GROUP(3, 0, BW_20),
+	MCS_GROUP(4, 0, BW_20),
+
+	MCS_GROUP(1, 1, BW_20),
+	MCS_GROUP(2, 1, BW_20),
+	MCS_GROUP(3, 1, BW_20),
+	MCS_GROUP(4, 1, BW_20),
+
+	MCS_GROUP(1, 0, BW_40),
+	MCS_GROUP(2, 0, BW_40),
+	MCS_GROUP(3, 0, BW_40),
+	MCS_GROUP(4, 0, BW_40),
+
+	MCS_GROUP(1, 1, BW_40),
+	MCS_GROUP(2, 1, BW_40),
+	MCS_GROUP(3, 1, BW_40),
+	MCS_GROUP(4, 1, BW_40),
+
+	VHT_GROUP(1, 0, BW_20),
+	VHT_GROUP(2, 0, BW_20),
+	VHT_GROUP(3, 0, BW_20),
+	VHT_GROUP(4, 0, BW_20),
+
+	VHT_GROUP(1, 1, BW_20),
+	VHT_GROUP(2, 1, BW_20),
+	VHT_GROUP(3, 1, BW_20),
+	VHT_GROUP(4, 1, BW_20),
+
+	VHT_GROUP(1, 0, BW_40),
+	VHT_GROUP(2, 0, BW_40),
+	VHT_GROUP(3, 0, BW_40),
+	VHT_GROUP(4, 0, BW_40),
+
+	VHT_GROUP(1, 1, BW_40),
+	VHT_GROUP(2, 1, BW_40),
+	VHT_GROUP(3, 1, BW_40),
+	VHT_GROUP(4, 1, BW_40),
+
+	VHT_GROUP(1, 0, BW_80),
+	VHT_GROUP(2, 0, BW_80),
+	VHT_GROUP(3, 0, BW_80),
+	VHT_GROUP(4, 0, BW_80),
+
+	VHT_GROUP(1, 1, BW_80),
+	VHT_GROUP(2, 1, BW_80),
+	VHT_GROUP(3, 1, BW_80),
+	VHT_GROUP(4, 1, BW_80),
+
+	VHT_GROUP(1, 0, BW_160),
+	VHT_GROUP(2, 0, BW_160),
+	VHT_GROUP(3, 0, BW_160),
+	VHT_GROUP(4, 0, BW_160),
+
+	VHT_GROUP(1, 1, BW_160),
+	VHT_GROUP(2, 1, BW_160),
+	VHT_GROUP(3, 1, BW_160),
+	VHT_GROUP(4, 1, BW_160),
+
+	HE_GROUP(1, HE_GI_08, BW_20),
+	HE_GROUP(2, HE_GI_08, BW_20),
+	HE_GROUP(3, HE_GI_08, BW_20),
+	HE_GROUP(4, HE_GI_08, BW_20),
+	HE_GROUP(5, HE_GI_08, BW_20),
+	HE_GROUP(6, HE_GI_08, BW_20),
+	HE_GROUP(7, HE_GI_08, BW_20),
+	HE_GROUP(8, HE_GI_08, BW_20),
+
+	HE_GROUP(1, HE_GI_16, BW_20),
+	HE_GROUP(2, HE_GI_16, BW_20),
+	HE_GROUP(3, HE_GI_16, BW_20),
+	HE_GROUP(4, HE_GI_16, BW_20),
+	HE_GROUP(5, HE_GI_16, BW_20),
+	HE_GROUP(6, HE_GI_16, BW_20),
+	HE_GROUP(7, HE_GI_16, BW_20),
+	HE_GROUP(8, HE_GI_16, BW_20),
+
+	HE_GROUP(1, HE_GI_32, BW_20),
+	HE_GROUP(2, HE_GI_32, BW_20),
+	HE_GROUP(3, HE_GI_32, BW_20),
+	HE_GROUP(4, HE_GI_32, BW_20),
+	HE_GROUP(5, HE_GI_32, BW_20),
+	HE_GROUP(6, HE_GI_32, BW_20),
+	HE_GROUP(7, HE_GI_32, BW_20),
+	HE_GROUP(8, HE_GI_32, BW_20),
+
+	HE_GROUP(1, HE_GI_08, BW_40),
+	HE_GROUP(2, HE_GI_08, BW_40),
+	HE_GROUP(3, HE_GI_08, BW_40),
+	HE_GROUP(4, HE_GI_08, BW_40),
+	HE_GROUP(5, HE_GI_08, BW_40),
+	HE_GROUP(6, HE_GI_08, BW_40),
+	HE_GROUP(7, HE_GI_08, BW_40),
+	HE_GROUP(8, HE_GI_08, BW_40),
+
+	HE_GROUP(1, HE_GI_16, BW_40),
+	HE_GROUP(2, HE_GI_16, BW_40),
+	HE_GROUP(3, HE_GI_16, BW_40),
+	HE_GROUP(4, HE_GI_16, BW_40),
+	HE_GROUP(5, HE_GI_16, BW_40),
+	HE_GROUP(6, HE_GI_16, BW_40),
+	HE_GROUP(7, HE_GI_16, BW_40),
+	HE_GROUP(8, HE_GI_16, BW_40),
+
+	HE_GROUP(1, HE_GI_32, BW_40),
+	HE_GROUP(2, HE_GI_32, BW_40),
+	HE_GROUP(3, HE_GI_32, BW_40),
+	HE_GROUP(4, HE_GI_32, BW_40),
+	HE_GROUP(5, HE_GI_32, BW_40),
+	HE_GROUP(6, HE_GI_32, BW_40),
+	HE_GROUP(7, HE_GI_32, BW_40),
+	HE_GROUP(8, HE_GI_32, BW_40),
+
+	HE_GROUP(1, HE_GI_08, BW_80),
+	HE_GROUP(2, HE_GI_08, BW_80),
+	HE_GROUP(3, HE_GI_08, BW_80),
+	HE_GROUP(4, HE_GI_08, BW_80),
+	HE_GROUP(5, HE_GI_08, BW_80),
+	HE_GROUP(6, HE_GI_08, BW_80),
+	HE_GROUP(7, HE_GI_08, BW_80),
+	HE_GROUP(8, HE_GI_08, BW_80),
+
+	HE_GROUP(1, HE_GI_16, BW_80),
+	HE_GROUP(2, HE_GI_16, BW_80),
+	HE_GROUP(3, HE_GI_16, BW_80),
+	HE_GROUP(4, HE_GI_16, BW_80),
+	HE_GROUP(5, HE_GI_16, BW_80),
+	HE_GROUP(6, HE_GI_16, BW_80),
+	HE_GROUP(7, HE_GI_16, BW_80),
+	HE_GROUP(8, HE_GI_16, BW_80),
+
+	HE_GROUP(1, HE_GI_32, BW_80),
+	HE_GROUP(2, HE_GI_32, BW_80),
+	HE_GROUP(3, HE_GI_32, BW_80),
+	HE_GROUP(4, HE_GI_32, BW_80),
+	HE_GROUP(5, HE_GI_32, BW_80),
+	HE_GROUP(6, HE_GI_32, BW_80),
+	HE_GROUP(7, HE_GI_32, BW_80),
+	HE_GROUP(8, HE_GI_32, BW_80),
+
+	HE_GROUP(1, HE_GI_08, BW_160),
+	HE_GROUP(2, HE_GI_08, BW_160),
+	HE_GROUP(3, HE_GI_08, BW_160),
+	HE_GROUP(4, HE_GI_08, BW_160),
+	HE_GROUP(5, HE_GI_08, BW_160),
+	HE_GROUP(6, HE_GI_08, BW_160),
+	HE_GROUP(7, HE_GI_08, BW_160),
+	HE_GROUP(8, HE_GI_08, BW_160),
+
+	HE_GROUP(1, HE_GI_16, BW_160),
+	HE_GROUP(2, HE_GI_16, BW_160),
+	HE_GROUP(3, HE_GI_16, BW_160),
+	HE_GROUP(4, HE_GI_16, BW_160),
+	HE_GROUP(5, HE_GI_16, BW_160),
+	HE_GROUP(6, HE_GI_16, BW_160),
+	HE_GROUP(7, HE_GI_16, BW_160),
+	HE_GROUP(8, HE_GI_16, BW_160),
+
+	HE_GROUP(1, HE_GI_32, BW_160),
+	HE_GROUP(2, HE_GI_32, BW_160),
+	HE_GROUP(3, HE_GI_32, BW_160),
+	HE_GROUP(4, HE_GI_32, BW_160),
+	HE_GROUP(5, HE_GI_32, BW_160),
+	HE_GROUP(6, HE_GI_32, BW_160),
+	HE_GROUP(7, HE_GI_32, BW_160),
+	HE_GROUP(8, HE_GI_32, BW_160),
+};
+
+static u32
+ieee80211_calc_legacy_rate_duration(u16 bitrate, bool short_pre,
+				    bool cck, int len)
+{
+	u32 duration;
+
+	if (cck) {
+		duration = 144 + 48; /* preamble + PLCP */
+		if (short_pre)
+			duration >>= 1;
+
+		duration += 10; /* SIFS */
+	} else {
+		duration = 20 + 16; /* premable + SIFS */
+	}
+
+	len <<= 3;
+	duration += (len * 10) / bitrate;
+
+	return duration;
+}
+
+u32 ieee80211_calc_rx_airtime(struct ieee80211_hw *hw,
+			      struct ieee80211_rx_status *status,
+			      int len)
+{
+	struct ieee80211_supported_band *sband;
+	const struct ieee80211_rate *rate;
+	bool sgi = status->enc_flags & RX_ENC_FLAG_SHORT_GI;
+	bool sp = status->enc_flags & RX_ENC_FLAG_SHORTPRE;
+	int bw, streams;
+	int group, idx;
+	u32 duration;
+	bool cck;
+
+	switch (status->bw) {
+	case RATE_INFO_BW_20:
+		bw = BW_20;
+		break;
+	case RATE_INFO_BW_40:
+		bw = BW_40;
+		break;
+	case RATE_INFO_BW_80:
+		bw = BW_80;
+		break;
+	case RATE_INFO_BW_160:
+		bw = BW_160;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	switch (status->encoding) {
+	case RX_ENC_LEGACY:
+		if (WARN_ON_ONCE(status->band > NL80211_BAND_5GHZ))
+			return 0;
+
+		sband = hw->wiphy->bands[status->band];
+		if (!sband || status->rate_idx > sband->n_bitrates)
+			return 0;
+
+		rate = &sband->bitrates[status->rate_idx];
+		cck = rate->flags & IEEE80211_RATE_MANDATORY_B;
+
+		return ieee80211_calc_legacy_rate_duration(rate->bitrate, sp,
+							   cck, len);
+
+	case RX_ENC_VHT:
+		streams = status->nss;
+		idx = status->rate_idx;
+		group = VHT_GROUP_IDX(streams, sgi, bw);
+		break;
+	case RX_ENC_HT:
+		streams = ((status->rate_idx >> 3) & 3) + 1;
+		idx = status->rate_idx & 7;
+		group = HT_GROUP_IDX(streams, sgi, bw);
+		break;
+	case RX_ENC_HE:
+		streams = status->nss;
+		idx = status->rate_idx;
+		group = HE_GROUP_IDX(streams, status->he_gi, bw);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	if (WARN_ON_ONCE((status->encoding != RX_ENC_HE && streams > 4) ||
+			 (status->encoding == RX_ENC_HE && streams > 8)))
+		return 0;
+
+	duration = airtime_mcs_groups[group].duration[idx];
+	duration <<= airtime_mcs_groups[group].shift;
+	duration *= len;
+	duration /= AVG_PKT_SIZE;
+	duration /= 1024;
+
+	duration += 36 + (streams << 2);
+
+	return duration;
+}
+EXPORT_SYMBOL_GPL(ieee80211_calc_rx_airtime);
+
+static u32 ieee80211_calc_tx_airtime_rate(struct ieee80211_hw *hw,
+					  struct ieee80211_tx_rate *rate,
+					  u8 band, int len)
+{
+	struct ieee80211_rx_status stat = {
+		.band = band,
+	};
+
+	if (rate->idx < 0 || !rate->count)
+		return 0;
+
+	if (rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
+		stat.bw = RATE_INFO_BW_80;
+	else if (rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+		stat.bw = RATE_INFO_BW_40;
+	else
+		stat.bw = RATE_INFO_BW_20;
+
+	stat.enc_flags = 0;
+	if (rate->flags & IEEE80211_TX_RC_USE_SHORT_PREAMBLE)
+		stat.enc_flags |= RX_ENC_FLAG_SHORTPRE;
+	if (rate->flags & IEEE80211_TX_RC_SHORT_GI)
+		stat.enc_flags |= RX_ENC_FLAG_SHORT_GI;
+
+	stat.rate_idx = rate->idx;
+	if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
+		stat.encoding = RX_ENC_VHT;
+		stat.rate_idx = ieee80211_rate_get_vht_mcs(rate);
+		stat.nss = ieee80211_rate_get_vht_nss(rate);
+	} else if (rate->flags & IEEE80211_TX_RC_MCS) {
+		stat.encoding = RX_ENC_HT;
+	} else {
+		stat.encoding = RX_ENC_LEGACY;
+	}
+
+	return ieee80211_calc_rx_airtime(hw, &stat, len);
+}
+
+u32 ieee80211_calc_tx_airtime(struct ieee80211_hw *hw,
+			      struct ieee80211_tx_info *info,
+			      int len)
+{
+	u32 duration = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(info->status.rates); i++) {
+		struct ieee80211_tx_rate *rate = &info->status.rates[i];
+		u32 cur_duration;
+
+		cur_duration = ieee80211_calc_tx_airtime_rate(hw, rate,
+							      info->band, len);
+		if (!cur_duration)
+			break;
+
+		duration += cur_duration * rate->count;
+	}
+
+	return duration;
+}
+EXPORT_SYMBOL_GPL(ieee80211_calc_tx_airtime);
+
+u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
+				       struct ieee80211_vif *vif,
+				       struct ieee80211_sta *pubsta,
+				       int len)
+{
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_chanctx_conf *conf;
+	int rateidx, shift = 0;
+	bool cck, short_pream;
+	u32 basic_rates;
+	u8 band = 0;
+	u16 rate;
+
+	len += 38; /* Ethernet header length */
+
+	conf = rcu_dereference(vif->chanctx_conf);
+	if (conf) {
+		band = conf->def.chan->band;
+		shift = ieee80211_chandef_get_shift(&conf->def);
+	}
+
+	if (pubsta) {
+		struct sta_info *sta = container_of(pubsta, struct sta_info,
+						    sta);
+
+		return ieee80211_calc_tx_airtime_rate(hw,
+						      &sta->tx_stats.last_rate,
+						      band, len);
+	}
+
+	if (!conf)
+		return 0;
+
+	/* No station to get latest rate from, so calculate the worst-case
+	 * duration using the lowest configured basic rate.
+	 */
+	sband = hw->wiphy->bands[band];
+
+	basic_rates = vif->bss_conf.basic_rates;
+	short_pream = vif->bss_conf.use_short_preamble;
+
+	rateidx = basic_rates ? ffs(basic_rates) - 1 : 0;
+	rate = sband->bitrates[rateidx].bitrate << shift;
+	cck = sband->bitrates[rateidx].flags & IEEE80211_RATE_MANDATORY_B;
+
+	return ieee80211_calc_legacy_rate_duration(rate, short_pream, cck, len);
+}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 05406e9c05b3..225ea4e3cd76 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2249,6 +2249,10 @@ const char *ieee80211_get_reason_code_string(u16 reason_code);
 
 extern const struct ethtool_ops ieee80211_ethtool_ops;
 
+u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
+				       struct ieee80211_vif *vif,
+				       struct ieee80211_sta *pubsta,
+				       int len);
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
 #else