diff options
author | Nick Kossifidis <mickflemm@gmail.com> | 2010-11-23 19:12:23 (GMT) |
---|---|---|
committer | John W. Linville <linville@tuxdriver.com> | 2010-11-30 18:53:21 (GMT) |
commit | 61cde037234c4b8e6497a23f5f236c64cbf9d41d (patch) | |
tree | ca988a018dc9d9e4f433f273d48d4ebe517eeec0 /drivers/net/wireless/ath/ath5k/pcu.c | |
parent | 3017fcab416d8d1ee48ca16aa9a3062f600dab8e (diff) | |
download | linux-fsl-qoriq-61cde037234c4b8e6497a23f5f236c64cbf9d41d.tar.xz |
ath5k: Extend rate_duration
* Extend ieee80211_generic_frame_duration to support the various
bwmodes.
* Better document what's going on with ack bitrates and update
write_rate_duration to support the standard ack bitrates (when
we don't set the high bit).
* Get rid of set_ack_bitrate_high and introduce a flag on ath5k_hw
for this (we only called the function on init anyway so there is no
difference).
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/ath/ath5k/pcu.c')
-rw-r--r-- | drivers/net/wireless/ath/ath5k/pcu.c | 159 |
1 files changed, 116 insertions, 43 deletions
diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c index 2118f70..e7f6be9c 100644 --- a/drivers/net/wireless/ath/ath5k/pcu.c +++ b/drivers/net/wireless/ath/ath5k/pcu.c @@ -31,11 +31,100 @@ #include "debug.h" #include "base.h" +/* + * AR5212+ can use higher rates for ack transmition + * based on current tx rate instead of the base rate. + * It does this to better utilize channel usage. + * This is a mapping between G rates (that cover both + * CCK and OFDM) and ack rates that we use when setting + * rate -> duration table. This mapping is hw-based so + * don't change anything. + * + * To enable this functionality we must set + * ah->ah_ack_bitrate_high to true else base rate is + * used (1Mb for CCK, 6Mb for OFDM). + */ +static const unsigned int ack_rates_high[] = +/* Tx -> ACK */ +/* 1Mb -> 1Mb */ { 0, +/* 2MB -> 2Mb */ 1, +/* 5.5Mb -> 2Mb */ 1, +/* 11Mb -> 2Mb */ 1, +/* 6Mb -> 6Mb */ 4, +/* 9Mb -> 6Mb */ 4, +/* 12Mb -> 12Mb */ 6, +/* 18Mb -> 12Mb */ 6, +/* 24Mb -> 24Mb */ 8, +/* 36Mb -> 24Mb */ 8, +/* 48Mb -> 24Mb */ 8, +/* 54Mb -> 24Mb */ 8 }; + /*******************\ * Helper functions * \*******************/ /** + * ath5k_hw_get_frame_duration - Get tx time of a frame + * + * @ah: The &struct ath5k_hw + * @len: Frame's length in bytes + * @rate: The @struct ieee80211_rate + * + * Calculate tx duration of a frame given it's rate and length + * It extends ieee80211_generic_frame_duration for non standard + * bwmodes. + */ +int ath5k_hw_get_frame_duration(struct ath5k_hw *ah, + int len, struct ieee80211_rate *rate) +{ + struct ath5k_softc *sc = ah->ah_sc; + int sifs, preamble, plcp_bits, sym_time; + int bitrate, bits, symbols, symbol_bits; + int dur; + + /* Fallback */ + if (!ah->ah_bwmode) { + dur = ieee80211_generic_frame_duration(sc->hw, + NULL, len, rate); + return dur; + } + + bitrate = rate->bitrate; + preamble = AR5K_INIT_OFDM_PREAMPLE_TIME; + plcp_bits = AR5K_INIT_OFDM_PLCP_BITS; + sym_time = AR5K_INIT_OFDM_SYMBOL_TIME; + + switch (ah->ah_bwmode) { + case AR5K_BWMODE_40MHZ: + sifs = AR5K_INIT_SIFS_TURBO; + preamble = AR5K_INIT_OFDM_PREAMBLE_TIME_MIN; + break; + case AR5K_BWMODE_10MHZ: + sifs = AR5K_INIT_SIFS_HALF_RATE; + preamble *= 2; + sym_time *= 2; + break; + case AR5K_BWMODE_5MHZ: + sifs = AR5K_INIT_SIFS_QUARTER_RATE; + preamble *= 4; + sym_time *= 4; + break; + default: + sifs = AR5K_INIT_SIFS_DEFAULT_BG; + break; + } + + bits = plcp_bits + (len << 3); + /* Bit rate is in 100Kbits */ + symbol_bits = bitrate * sym_time; + symbols = DIV_ROUND_UP(bits * 10, symbol_bits); + + dur = sifs + preamble + (sym_time * symbols); + + return dur; +} + +/** * ath5k_hw_get_default_slottime - Get the default slot time for current mode * * @ah: The &struct ath5k_hw @@ -120,43 +209,11 @@ void ath5k_hw_update_mib_counters(struct ath5k_hw *ah) stats->beacons += ath5k_hw_reg_read(ah, AR5K_BEACON_CNT); } -/** - * ath5k_hw_set_ack_bitrate - set bitrate for ACKs - * - * @ah: The &struct ath5k_hw - * @high: Flag to determine if we want to use high transmission rate - * for ACKs or not - * - * If high flag is set, we tell hw to use a set of control rates based on - * the current transmission rate (check out control_rates array inside reset.c). - * If not hw just uses the lowest rate available for the current modulation - * scheme being used (1Mbit for CCK and 6Mbits for OFDM). - */ -void ath5k_hw_set_ack_bitrate_high(struct ath5k_hw *ah, bool high) -{ - if (ah->ah_version != AR5K_AR5212) - return; - else { - u32 val = AR5K_STA_ID1_BASE_RATE_11B | AR5K_STA_ID1_ACKCTS_6MB; - if (high) - AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, val); - else - AR5K_REG_ENABLE_BITS(ah, AR5K_STA_ID1, val); - } -} - /******************\ * ACK/CTS Timeouts * \******************/ -/* - * index into rates for control rates, we can set it up like this because - * this is only used for AR5212 and we know it supports G mode - */ -static const unsigned int control_rates[] = - { 0, 1, 1, 1, 4, 4, 6, 6, 8, 8, 8, 8 }; - /** * ath5k_hw_write_rate_duration - fill rate code to duration table * @@ -164,7 +221,7 @@ static const unsigned int control_rates[] = * @mode: one of enum ath5k_driver_mode * * Write the rate code to duration table upon hw reset. This is a helper for - * ath5k_hw_reset(). It seems all this is doing is setting an ACK timeout on + * ath5k_hw_pcu_init(). It seems all this is doing is setting an ACK timeout on * the hardware, based on current mode, for each rate. The rates which are * capable of short preamble (802.11b rates 2Mbps, 5.5Mbps, and 11Mbps) have * different rate code so we write their value twice (one for long preamble @@ -172,23 +229,30 @@ static const unsigned int control_rates[] = * * Note: Band doesn't matter here, if we set the values for OFDM it works * on both a and g modes. So all we have to do is set values for all g rates - * that include all OFDM and CCK rates. If we operate in turbo or xr/half/ - * quarter rate mode, we need to use another set of bitrates (that's why we - * need the mode parameter) but we don't handle these proprietary modes yet. + * that include all OFDM and CCK rates. + * */ -static inline void ath5k_hw_write_rate_duration(struct ath5k_hw *ah, - unsigned int mode) +static inline void ath5k_hw_write_rate_duration(struct ath5k_hw *ah) { struct ath5k_softc *sc = ah->ah_sc; struct ieee80211_rate *rate; unsigned int i; + /* 802.11g covers both OFDM and CCK */ + u8 band = IEEE80211_BAND_2GHZ; /* Write rate duration table */ - for (i = 0; i < sc->sbands[IEEE80211_BAND_2GHZ].n_bitrates; i++) { + for (i = 0; i < sc->sbands[band].n_bitrates; i++) { u32 reg; u16 tx_time; - rate = &sc->sbands[IEEE80211_BAND_2GHZ].bitrates[control_rates[i]]; + if (ah->ah_ack_bitrate_high) + rate = &sc->sbands[band].bitrates[ack_rates_high[i]]; + /* CCK -> 1Mb */ + else if (i < 4) + rate = &sc->sbands[band].bitrates[0]; + /* OFDM -> 6Mb */ + else + rate = &sc->sbands[band].bitrates[4]; /* Set ACK timeout */ reg = AR5K_RATE_DUR(rate->hw_value); @@ -199,8 +263,9 @@ static inline void ath5k_hw_write_rate_duration(struct ath5k_hw *ah, * actual rate for this rate. See mac80211 tx.c * ieee80211_duration() for a brief description of * what rate we should choose to TX ACKs. */ - tx_time = le16_to_cpu(ieee80211_generic_frame_duration(sc->hw, - NULL, 10, rate)); + tx_time = ath5k_hw_get_frame_duration(ah, 10, rate); + + tx_time = le16_to_cpu(tx_time); ath5k_hw_reg_write(ah, tx_time, reg); @@ -835,7 +900,7 @@ void ath5k_hw_pcu_init(struct ath5k_hw *ah, enum nl80211_iftype op_mode, * mac80211 are integrated */ if (ah->ah_version == AR5K_AR5212 && ah->ah_sc->nvifs) - ath5k_hw_write_rate_duration(ah, mode); + ath5k_hw_write_rate_duration(ah); /* Set RSSI/BRSSI thresholds * @@ -869,5 +934,13 @@ void ath5k_hw_pcu_init(struct ath5k_hw *ah, enum nl80211_iftype op_mode, if (ah->ah_coverage_class > 0) ath5k_hw_set_coverage_class(ah, ah->ah_coverage_class); + /* Set ACK bitrate mode (see ack_rates_high) */ + if (ah->ah_version == AR5K_AR5212) { + u32 val = AR5K_STA_ID1_BASE_RATE_11B | AR5K_STA_ID1_ACKCTS_6MB; + if (ah->ah_ack_bitrate_high) + AR5K_REG_DISABLE_BITS(ah, AR5K_STA_ID1, val); + else + AR5K_REG_ENABLE_BITS(ah, AR5K_STA_ID1, val); + } return; } |