[PATCH] rt2x00: Implement SW diversity
When mac80211 indicates that the default antenna setup should be used _and_ that this default setup is SW_DIVERSITY. This requires sampling and storing the RSSI per antenna and check once every 2 seconds to determine if the RSSI has changed significantly. Once this is the case we should sample the other antenna for a short period and evaluate if we need to swap antenna or not. Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ivo van Doorn
David S. Miller
parent
8de8c5162b
commit
69f81a2cac
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@ -240,6 +240,43 @@ struct link_qual {
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#define WEIGHT_TX 40
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};
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/*
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* Antenna settings about the currently active link.
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*/
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struct link_ant {
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/*
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* Antenna flags
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*/
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unsigned int flags;
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#define ANTENNA_RX_DIVERSITY 0x00000001
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#define ANTENNA_TX_DIVERSITY 0x00000002
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#define ANTENNA_MODE_SAMPLE 0x00000004
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/*
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* Currently active TX/RX antenna setup.
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* When software diversity is used, this will indicate
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* which antenna is actually used at this time.
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*/
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struct antenna_setup active;
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/*
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* RSSI information for the different antenna's.
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* These statistics are used to determine when
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* to switch antenna when using software diversity.
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*
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* rssi[0] -> Antenna A RSSI
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* rssi[1] -> Antenna B RSSI
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*/
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int rssi_history[2];
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/*
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* Current RSSI average of the currently active antenna.
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* Similar to the avg_rssi in the link_qual structure
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* this value is updated by using the walking average.
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*/
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int rssi_ant;
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};
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/*
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* To optimize the quality of the link we need to store
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* the quality of received frames and periodically
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@ -259,11 +296,9 @@ struct link {
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struct link_qual qual;
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/*
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* Currently active TX/RX antenna setup.
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* When software diversity is used, this will indicate
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* which antenna is actually used at this time.
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* TX/RX antenna setup.
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*/
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struct antenna_setup active_ant;
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struct link_ant ant;
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/*
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* Active VGC level
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@ -277,25 +312,47 @@ struct link {
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};
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/*
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* Update the rssi using the walking average approach.
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* Small helper macro to work with moving/walking averages.
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*/
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static inline void rt2x00_update_link_rssi(struct link *link, int rssi)
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{
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if (link->qual.avg_rssi)
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rssi = ((link->qual.avg_rssi * 7) + rssi) / 8;
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link->qual.avg_rssi = rssi;
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}
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#define MOVING_AVERAGE(__avg, __val, __samples) \
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( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) )
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/*
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* When the avg_rssi is unset or no frames have been received),
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* we need to return the default value which needs to be less
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* than -80 so the device will select the maximum sensitivity.
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* When we lack RSSI information return something less then -80 to
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* tell the driver to tune the device to maximum sensitivity.
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*/
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#define DEFAULT_RSSI ( -128 )
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/*
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* Link quality access functions.
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*/
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static inline int rt2x00_get_link_rssi(struct link *link)
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{
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if (link->qual.avg_rssi && link->qual.rx_success)
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return link->qual.avg_rssi;
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return -128;
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return DEFAULT_RSSI;
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}
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static inline int rt2x00_get_link_ant_rssi(struct link *link)
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{
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if (link->ant.rssi_ant && link->qual.rx_success)
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return link->ant.rssi_ant;
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return DEFAULT_RSSI;
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}
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static inline int rt2x00_get_link_ant_rssi_history(struct link *link,
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enum antenna ant)
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{
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if (link->ant.rssi_history[ant - ANTENNA_A])
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return link->ant.rssi_history[ant - ANTENNA_A];
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return DEFAULT_RSSI;
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}
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static inline int rt2x00_update_ant_rssi(struct link *link, int rssi)
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{
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int old_rssi = link->ant.rssi_history[link->ant.active.rx - ANTENNA_A];
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link->ant.rssi_history[link->ant.active.rx - ANTENNA_A] = rssi;
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return old_rssi;
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}
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/*
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@ -94,6 +94,26 @@ void rt2x00lib_config_type(struct rt2x00_dev *rt2x00dev, const int type)
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rt2x00dev->ops->lib->config_type(rt2x00dev, type, tsf_sync);
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}
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void rt2x00lib_config_antenna(struct rt2x00_dev *rt2x00dev,
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enum antenna rx, enum antenna tx)
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{
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struct rt2x00lib_conf libconf;
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libconf.ant.rx = rx;
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libconf.ant.tx = tx;
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/*
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* Write new antenna setup to device and reset the link tuner.
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* The latter is required since we need to recalibrate the
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* noise-sensitivity ratio for the new setup.
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*/
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rt2x00dev->ops->lib->config(rt2x00dev, CONFIG_UPDATE_ANTENNA, &libconf);
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rt2x00lib_reset_link_tuner(rt2x00dev);
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rt2x00dev->link.ant.active.rx = libconf.ant.rx;
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rt2x00dev->link.ant.active.tx = libconf.ant.tx;
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}
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void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
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struct ieee80211_conf *conf, const int force_config)
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{
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@ -101,7 +121,7 @@ void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
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struct ieee80211_hw_mode *mode;
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struct ieee80211_rate *rate;
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struct antenna_setup *default_ant = &rt2x00dev->default_ant;
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struct antenna_setup *active_ant = &rt2x00dev->link.active_ant;
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struct antenna_setup *active_ant = &rt2x00dev->link.ant.active;
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int flags = 0;
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int short_slot_time;
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@ -247,6 +267,6 @@ config:
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rt2x00dev->rx_status.freq = conf->freq;
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rt2x00dev->rx_status.channel = conf->channel;
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rt2x00dev->tx_power = conf->power_level;
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rt2x00dev->link.active_ant.rx = libconf.ant.rx;
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rt2x00dev->link.active_ant.tx = libconf.ant.tx;
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rt2x00dev->link.ant.active.rx = libconf.ant.rx;
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rt2x00dev->link.ant.active.tx = libconf.ant.tx;
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}
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@ -193,6 +193,133 @@ void rt2x00lib_toggle_rx(struct rt2x00_dev *rt2x00dev, enum dev_state state)
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rt2x00lib_start_link_tuner(rt2x00dev);
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}
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static void rt2x00lib_evaluate_antenna_sample(struct rt2x00_dev *rt2x00dev)
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{
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enum antenna rx = rt2x00dev->link.ant.active.rx;
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enum antenna tx = rt2x00dev->link.ant.active.tx;
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int sample_a =
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rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_A);
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int sample_b =
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rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_B);
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/*
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* We are done sampling. Now we should evaluate the results.
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*/
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rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;
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/*
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* During the last period we have sampled the RSSI
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* from both antenna's. It now is time to determine
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* which antenna demonstrated the best performance.
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* When we are already on the antenna with the best
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* performance, then there really is nothing for us
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* left to do.
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*/
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if (sample_a == sample_b)
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return;
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if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) {
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if (sample_a > sample_b && rx == ANTENNA_B)
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rx = ANTENNA_A;
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else if (rx == ANTENNA_A)
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rx = ANTENNA_B;
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}
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if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY) {
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if (sample_a > sample_b && tx == ANTENNA_B)
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tx = ANTENNA_A;
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else if (tx == ANTENNA_A)
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tx = ANTENNA_B;
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}
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rt2x00lib_config_antenna(rt2x00dev, rx, tx);
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}
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static void rt2x00lib_evaluate_antenna_eval(struct rt2x00_dev *rt2x00dev)
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{
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enum antenna rx = rt2x00dev->link.ant.active.rx;
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enum antenna tx = rt2x00dev->link.ant.active.tx;
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int rssi_curr = rt2x00_get_link_ant_rssi(&rt2x00dev->link);
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int rssi_old = rt2x00_update_ant_rssi(&rt2x00dev->link, rssi_curr);
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/*
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* Legacy driver indicates that we should swap antenna's
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* when the difference in RSSI is greater that 5. This
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* also should be done when the RSSI was actually better
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* then the previous sample.
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* When the difference exceeds the threshold we should
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* sample the rssi from the other antenna to make a valid
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* comparison between the 2 antennas.
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*/
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if ((rssi_curr - rssi_old) > -5 || (rssi_curr - rssi_old) < 5)
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return;
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rt2x00dev->link.ant.flags |= ANTENNA_MODE_SAMPLE;
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if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
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rx = (rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
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if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
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tx = (tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
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rt2x00lib_config_antenna(rt2x00dev, rx, tx);
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}
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static void rt2x00lib_evaluate_antenna(struct rt2x00_dev *rt2x00dev)
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{
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/*
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* Determine if software diversity is enabled for
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* either the TX or RX antenna (or both).
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* Always perform this check since within the link
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* tuner interval the configuration might have changed.
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*/
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rt2x00dev->link.ant.flags &= ~ANTENNA_RX_DIVERSITY;
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rt2x00dev->link.ant.flags &= ~ANTENNA_TX_DIVERSITY;
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if (rt2x00dev->hw->conf.antenna_sel_rx == 0 &&
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rt2x00dev->default_ant.rx != ANTENNA_SW_DIVERSITY)
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rt2x00dev->link.ant.flags |= ANTENNA_RX_DIVERSITY;
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if (rt2x00dev->hw->conf.antenna_sel_tx == 0 &&
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rt2x00dev->default_ant.tx != ANTENNA_SW_DIVERSITY)
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rt2x00dev->link.ant.flags |= ANTENNA_TX_DIVERSITY;
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if (!(rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) &&
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!(rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)) {
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rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;
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return;
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}
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/*
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* If we have only sampled the data over the last period
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* we should now harvest the data. Otherwise just evaluate
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* the data. The latter should only be performed once
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* every 2 seconds.
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*/
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if (rt2x00dev->link.ant.flags & ANTENNA_MODE_SAMPLE)
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rt2x00lib_evaluate_antenna_sample(rt2x00dev);
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else if (rt2x00dev->link.count & 1)
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rt2x00lib_evaluate_antenna_eval(rt2x00dev);
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}
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static void rt2x00lib_update_link_stats(struct link *link, int rssi)
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{
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int avg_rssi = rssi;
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/*
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* Update global RSSI
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*/
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if (link->qual.avg_rssi)
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avg_rssi = MOVING_AVERAGE(link->qual.avg_rssi, rssi, 8);
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link->qual.avg_rssi = avg_rssi;
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/*
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* Update antenna RSSI
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*/
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if (link->ant.rssi_ant)
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rssi = MOVING_AVERAGE(link->ant.rssi_ant, rssi, 8);
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link->ant.rssi_ant = rssi;
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}
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static void rt2x00lib_precalculate_link_signal(struct link_qual *qual)
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{
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if (qual->rx_failed || qual->rx_success)
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@ -261,7 +388,6 @@ static void rt2x00lib_link_tuner(struct work_struct *work)
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* Update statistics.
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*/
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rt2x00dev->ops->lib->link_stats(rt2x00dev, &rt2x00dev->link.qual);
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rt2x00dev->low_level_stats.dot11FCSErrorCount +=
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rt2x00dev->link.qual.rx_failed;
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@ -272,6 +398,11 @@ static void rt2x00lib_link_tuner(struct work_struct *work)
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if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags))
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rt2x00dev->ops->lib->link_tuner(rt2x00dev);
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/*
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* Evaluate antenna setup.
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*/
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rt2x00lib_evaluate_antenna(rt2x00dev);
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/*
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* Precalculate a portion of the link signal which is
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* in based on the tx/rx success/failure counters.
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@ -426,14 +557,15 @@ void rt2x00lib_rxdone(struct data_entry *entry, struct sk_buff *skb,
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}
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}
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rt2x00_update_link_rssi(&rt2x00dev->link, desc->rssi);
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rt2x00lib_update_link_stats(&rt2x00dev->link, desc->rssi);
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rt2x00dev->link.qual.rx_success++;
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rx_status->rate = val;
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rx_status->signal =
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rt2x00lib_calculate_link_signal(rt2x00dev, desc->rssi);
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rx_status->ssi = desc->rssi;
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rx_status->flag = desc->flags;
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rx_status->antenna = rt2x00dev->link.active_ant.rx;
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rx_status->antenna = rt2x00dev->link.ant.active.rx;
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/*
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* Send frame to mac80211
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@ -53,6 +53,8 @@ void rt2x00lib_uninitialize(struct rt2x00_dev *rt2x00dev);
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void rt2x00lib_config_mac_addr(struct rt2x00_dev *rt2x00dev, u8 *mac);
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void rt2x00lib_config_bssid(struct rt2x00_dev *rt2x00dev, u8 *bssid);
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void rt2x00lib_config_type(struct rt2x00_dev *rt2x00dev, const int type);
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void rt2x00lib_config_antenna(struct rt2x00_dev *rt2x00dev,
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enum antenna rx, enum antenna tx);
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void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
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struct ieee80211_conf *conf, const int force_config);
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