path: root/net/mac80211/rc80211_minstrel_ht.c

/*
 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/debugfs.h>
#include <linux/random.h>
#include <linux/moduleparam.h>
#include <linux/ieee80211.h>
#include <net/mac80211.h>
#include "rate.h"
#include "sta_info.h"
#include "rc80211_minstrel.h"
#include "rc80211_minstrel_ht.h"

#define AVG_AMPDU_SIZE	16
#define AVG_PKT_SIZE	1200

/* Number of bits for an average sized packet */
#define MCS_NBITS ((AVG_PKT_SIZE * AVG_AMPDU_SIZE) << 3)

/* Number of symbols for a packet with (bps) bits per symbol */
#define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))

/* Transmission time (nanoseconds) for a packet containing (syms) symbols */
#define MCS_SYMBOL_TIME(sgi, syms)					\
	(sgi ?								\
	  ((syms) * 18000 + 4000) / 5 :	/* syms * 3.6 us */		\
	  ((syms) * 1000) << 2		/* syms * 4 us */		\
	)

/* Transmit duration for the raw data part of an average sized packet */
#define MCS_DURATION(streams, sgi, bps) \
	(MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps))) / AVG_AMPDU_SIZE)

#define BW_20			0
#define BW_40			1
#define BW_80			2

/*
 * Define group sort order: HT40 -> SGI -> #streams
 */
#define GROUP_IDX(_streams, _sgi, _ht40)	\
	MINSTREL_HT_GROUP_0 +			\
	MINSTREL_MAX_STREAMS * 2 * _ht40 +	\
	MINSTREL_MAX_STREAMS * _sgi +	\
	_streams - 1

/* MCS rate information for an MCS group */
#define MCS_GROUP(_streams, _sgi, _ht40)				\
	[GROUP_IDX(_streams, _sgi, _ht40)] = {				\
	.streams = _streams,						\
	.flags =							\
		IEEE80211_TX_RC_MCS |					\
		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
		(_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),		\
	.duration = {							\
		MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78),		\
		MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234),	\
		MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260)		\
	}								\
}

#define VHT_GROUP_IDX(_streams, _sgi, _bw)				\
	(MINSTREL_VHT_GROUP_0 +						\
	 MINSTREL_MAX_STREAMS * 2 * (_bw) +				\
	 MINSTREL_MAX_STREAMS * (_sgi) +				\
	 (_streams) - 1)

#define BW2VBPS(_bw, r3, r2, r1)					\
	(_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)

#define VHT_GROUP(_streams, _sgi, _bw)					\
	[VHT_GROUP_IDX(_streams, _sgi, _bw)] = {			\
	.streams = _streams,						\
	.flags =							\
		IEEE80211_TX_RC_VHT_MCS |				\
		(_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |			\
		(_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :		\
		 _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),	\
	.duration = {							\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  117,  54,  26)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  234, 108,  52)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  351, 162,  78)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  468, 216, 104)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  702, 324, 156)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw,  936, 432, 208)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1053, 486, 234)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1170, 540, 260)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1404, 648, 312)),		\
		MCS_DURATION(_streams, _sgi,				\
			     BW2VBPS(_bw, 1560, 720, 346))		\
	}								\
}

#define CCK_DURATION(_bitrate, _short, _len)		\
	(1000 * (10 /* SIFS */ +			\
	 (_short ? 72 + 24 : 144 + 48) +		\
	 (8 * (_len + 4) * 10) / (_bitrate)))

#define CCK_ACK_DURATION(_bitrate, _short)			\
	(CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) +	\
	 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))

#define CCK_DURATION_LIST