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@xxxxxxxxx>
---
drivers/net/wireless/rt2x00/rt2x00.h | 87 ++++++++++++++---
drivers/net/wireless/rt2x00/rt2x00config.c | 26 +++++-
drivers/net/wireless/rt2x00/rt2x00dev.c | 138 +++++++++++++++++++++++++++-
drivers/net/wireless/rt2x00/rt2x00lib.h | 2 +
4 files changed, 232 insertions(+), 21 deletions(-)
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index acf6f1c..c9df8f1 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -241,6 +241,43 @@ struct link_qual {
};
/*
+ * Antenna settings about the currently active link.
+ */
+struct link_ant {
+ /*
+ * Antenna flags
+ */
+ unsigned int flags;
+#define ANTENNA_RX_DIVERSITY 0x00000001
+#define ANTENNA_TX_DIVERSITY 0x00000002
+#define ANTENNA_MODE_SAMPLE 0x00000004
+
+ /*
+ * Currently active TX/RX antenna setup.
+ * When software diversity is used, this will indicate
+ * which antenna is actually used at this time.
+ */
+ struct antenna_setup active;
+
+ /*
+ * RSSI information for the different antenna's.
+ * These statistics are used to determine when
+ * to switch antenna when using software diversity.
+ *
+ * rssi[0] -> Antenna A RSSI
+ * rssi[1] -> Antenna B RSSI
+ */
+ int rssi_history[2];
+
+ /*
+ * Current RSSI average of the currently active antenna.
+ * Similar to the avg_rssi in the link_qual structure
+ * this value is updated by using the walking average.
+ */
+ int rssi_ant;
+};
+
+/*
* To optimize the quality of the link we need to store
* the quality of received frames and periodically
* optimize the link.
@@ -259,11 +296,9 @@ struct link {
struct link_qual qual;
/*
- * Currently active TX/RX antenna setup.
- * When software diversity is used, this will indicate
- * which antenna is actually used at this time.
+ * TX/RX antenna setup.
*/
- struct antenna_setup active_ant;
+ struct link_ant ant;
/*
* Active VGC level
@@ -277,25 +312,47 @@ struct link {
};
/*
- * Update the rssi using the walking average approach.
+ * Small helper macro to work with moving/walking averages.
*/
-static inline void rt2x00_update_link_rssi(struct link *link, int rssi)
-{
- if (link->qual.avg_rssi)
- rssi = ((link->qual.avg_rssi * 7) + rssi) / 8;
- link->qual.avg_rssi = rssi;
-}
+#define MOVING_AVERAGE(__avg, __val, __samples) \
+ ( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) )
+
+/*
+ * When we lack RSSI information return something less then -80 to
+ * tell the driver to tune the device to maximum sensitivity.
+ */
+#define DEFAULT_RSSI ( -128 )
/*
- * When the avg_rssi is unset or no frames have been received),
- * we need to return the default value which needs to be less
- * than -80 so the device will select the maximum sensitivity.
+ * Link quality access functions.
*/
static inline int rt2x00_get_link_rssi(struct link *link)
{
if (link->qual.avg_rssi && link->qual.rx_success)
return link->qual.avg_rssi;
- return -128;
+ return DEFAULT_RSSI;
+}
+
+static inline int rt2x00_get_link_ant_rssi(struct link *link)
+{
+ if (link->ant.rssi_ant && link->qual.rx_success)
+ return link->ant.rssi_ant;
+ return DEFAULT_RSSI;
+}
+
+static inline int rt2x00_get_link_ant_rssi_history(struct link *link,
+ enum antenna ant)
+{
+ if (link->ant.rssi_history[ant - ANTENNA_A])
+ return link->ant.rssi_history[ant - ANTENNA_A];
+ return DEFAULT_RSSI;
+}
+
+static inline int rt2x00_update_ant_rssi(struct link *link, int rssi)
+{
+ int old_rssi = link->ant.rssi_history[link->ant.active.rx - ANTENNA_A];
+ link->ant.rssi_history[link->ant.active.rx - ANTENNA_A] = rssi;
+ return old_rssi;
}
/*
diff --git a/drivers/net/wireless/rt2x00/rt2x00config.c b/drivers/net/wireless/rt2x00/rt2x00config.c
index 04518b0..2b0edd2 100644
--- a/drivers/net/wireless/rt2x00/rt2x00config.c
+++ b/drivers/net/wireless/rt2x00/rt2x00config.c
@@ -94,6 +94,26 @@ void rt2x00lib_config_type(struct rt2x00_dev *rt2x00dev, const int type)
rt2x00dev->ops->lib->config_type(rt2x00dev, type, tsf_sync);
}
+void rt2x00lib_config_antenna(struct rt2x00_dev *rt2x00dev,
+ enum antenna rx, enum antenna tx)
+{
+ struct rt2x00lib_conf libconf;
+
+ libconf.ant.rx = rx;
+ libconf.ant.tx = tx;
+
+ /*
+ * Write new antenna setup to device and reset the link tuner.
+ * The latter is required since we need to recalibrate the
+ * noise-sensitivity ratio for the new setup.
+ */
+ rt2x00dev->ops->lib->config(rt2x00dev, CONFIG_UPDATE_ANTENNA, &libconf);
+ rt2x00lib_reset_link_tuner(rt2x00dev);
+
+ rt2x00dev->link.ant.active.rx = libconf.ant.rx;
+ rt2x00dev->link.ant.active.tx = libconf.ant.tx;
+}
+
void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
struct ieee80211_conf *conf, const int force_config)
{
@@ -101,7 +121,7 @@ void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
struct ieee80211_hw_mode *mode;
struct ieee80211_rate *rate;
struct antenna_setup *default_ant = &rt2x00dev->default_ant;
- struct antenna_setup *active_ant = &rt2x00dev->link.active_ant;
+ struct antenna_setup *active_ant = &rt2x00dev->link.ant.active;
int flags = 0;
int short_slot_time;
@@ -247,6 +267,6 @@ config:
rt2x00dev->rx_status.freq = conf->freq;
rt2x00dev->rx_status.channel = conf->channel;
rt2x00dev->tx_power = conf->power_level;
- rt2x00dev->link.active_ant.rx = libconf.ant.rx;
- rt2x00dev->link.active_ant.tx = libconf.ant.tx;
+ rt2x00dev->link.ant.active.rx = libconf.ant.rx;
+ rt2x00dev->link.ant.active.tx = libconf.ant.tx;
}
diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
index 0f824b2..360f03a 100644
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -193,6 +193,133 @@ void rt2x00lib_toggle_rx(struct rt2x00_dev *rt2x00dev, enum dev_state state)
rt2x00lib_start_link_tuner(rt2x00dev);
}
+static void rt2x00lib_evaluate_antenna_sample(struct rt2x00_dev *rt2x00dev)
+{
+ enum antenna rx = rt2x00dev->link.ant.active.rx;
+ enum antenna tx = rt2x00dev->link.ant.active.tx;
+ int sample_a =
+ rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_A);
+ int sample_b =
+ rt2x00_get_link_ant_rssi_history(&rt2x00dev->link, ANTENNA_B);
+
+ /*
+ * We are done sampling. Now we should evaluate the results.
+ */
+ rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;
+
+ /*
+ * During the last period we have sampled the RSSI
+ * from both antenna's. It now is time to determine
+ * which antenna demonstrated the best performance.
+ * When we are already on the antenna with the best
+ * performance, then there really is nothing for us
+ * left to do.
+ */
+ if (sample_a == sample_b)
+ return;
+
+ if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) {
+ if (sample_a > sample_b && rx == ANTENNA_B)
+ rx = ANTENNA_A;
+ else if (rx == ANTENNA_A)
+ rx = ANTENNA_B;
+ }
+
+ if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY) {
+ if (sample_a > sample_b && tx == ANTENNA_B)
+ tx = ANTENNA_A;
+ else if (tx == ANTENNA_A)
+ tx = ANTENNA_B;
+ }
+
+ rt2x00lib_config_antenna(rt2x00dev, rx, tx);
+}
+
+static void rt2x00lib_evaluate_antenna_eval(struct rt2x00_dev *rt2x00dev)
+{
+ enum antenna rx = rt2x00dev->link.ant.active.rx;
+ enum antenna tx = rt2x00dev->link.ant.active.tx;
+ int rssi_curr = rt2x00_get_link_ant_rssi(&rt2x00dev->link);
+ int rssi_old = rt2x00_update_ant_rssi(&rt2x00dev->link, rssi_curr);
+
+ /*
+ * Legacy driver indicates that we should swap antenna's
+ * when the difference in RSSI is greater that 5. This
+ * also should be done when the RSSI was actually better
+ * then the previous sample.
+ * When the difference exceeds the threshold we should
+ * sample the rssi from the other antenna to make a valid
+ * comparison between the 2 antennas.
+ */
+ if ((rssi_curr - rssi_old) > -5 || (rssi_curr - rssi_old) < 5)
+ return;
+
+ rt2x00dev->link.ant.flags |= ANTENNA_MODE_SAMPLE;
+
+ if (rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY)
+ rx = (rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
+
+ if (rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)
+ tx = (tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
+
+ rt2x00lib_config_antenna(rt2x00dev, rx, tx);
+}
+
+static void rt2x00lib_evaluate_antenna(struct rt2x00_dev *rt2x00dev)
+{
+ /*
+ * Determine if software diversity is enabled for
+ * either the TX or RX antenna (or both).
+ * Always perform this check since within the link
+ * tuner interval the configuration might have changed.
+ */
+ rt2x00dev->link.ant.flags &= ~ANTENNA_RX_DIVERSITY;
+ rt2x00dev->link.ant.flags &= ~ANTENNA_TX_DIVERSITY;
+
+ if (rt2x00dev->hw->conf.antenna_sel_rx == 0 &&
+ rt2x00dev->default_ant.rx != ANTENNA_SW_DIVERSITY)
+ rt2x00dev->link.ant.flags |= ANTENNA_RX_DIVERSITY;
+ if (rt2x00dev->hw->conf.antenna_sel_tx == 0 &&
+ rt2x00dev->default_ant.tx != ANTENNA_SW_DIVERSITY)
+ rt2x00dev->link.ant.flags |= ANTENNA_TX_DIVERSITY;
+
+ if (!(rt2x00dev->link.ant.flags & ANTENNA_RX_DIVERSITY) &&
+ !(rt2x00dev->link.ant.flags & ANTENNA_TX_DIVERSITY)) {
+ rt2x00dev->link.ant.flags &= ~ANTENNA_MODE_SAMPLE;
+ return;
+ }
+
+ /*
+ * If we have only sampled the data over the last period
+ * we should now harvest the data. Otherwise just evaluate
+ * the data. The latter should only be performed once
+ * every 2 seconds.
+ */
+ if (rt2x00dev->link.ant.flags & ANTENNA_MODE_SAMPLE)
+ rt2x00lib_evaluate_antenna_sample(rt2x00dev);
+ else if (rt2x00dev->link.count & 1)
+ rt2x00lib_evaluate_antenna_eval(rt2x00dev);
+}
+
+static void rt2x00lib_update_link_stats(struct link *link, int rssi)
+{
+ int avg_rssi = rssi;
+
+ /*
+ * Update global RSSI
+ */
+ if (link->qual.avg_rssi)
+ avg_rssi = MOVING_AVERAGE(link->qual.avg_rssi, rssi, 8);
+ link->qual.avg_rssi = avg_rssi;
+
+ /*
+ * Update antenna RSSI
+ */
+ if (link->ant.rssi_ant)
+ rssi = MOVING_AVERAGE(link->ant.rssi_ant, rssi, 8);
+ link->ant.rssi_ant = rssi;
+}
+
static void rt2x00lib_precalculate_link_signal(struct link_qual *qual)
{
if (qual->rx_failed || qual->rx_success)
@@ -261,7 +388,6 @@ static void rt2x00lib_link_tuner(struct work_struct *work)
* Update statistics.
*/
rt2x00dev->ops->lib->link_stats(rt2x00dev, &rt2x00dev->link.qual);
-
rt2x00dev->low_level_stats.dot11FCSErrorCount +=
rt2x00dev->link.qual.rx_failed;
@@ -273,6 +399,11 @@ static void rt2x00lib_link_tuner(struct work_struct *work)
rt2x00dev->ops->lib->link_tuner(rt2x00dev);
/*
+ * Evaluate antenna setup.
+ */
+ rt2x00lib_evaluate_antenna(rt2x00dev);
+
+ /*
* Precalculate a portion of the link signal which is
* in based on the tx/rx success/failure counters.
*/
@@ -426,14 +557,15 @@ void rt2x00lib_rxdone(struct data_entry *entry, struct sk_buff *skb,
}
}
- rt2x00_update_link_rssi(&rt2x00dev->link, desc->rssi);
+ rt2x00lib_update_link_stats(&rt2x00dev->link, desc->rssi);
rt2x00dev->link.qual.rx_success++;
+
rx_status->rate = val;
rx_status->signal =
rt2x00lib_calculate_link_signal(rt2x00dev, desc->rssi);
rx_status->ssi = desc->rssi;
rx_status->flag = desc->flags;
- rx_status->antenna = rt2x00dev->link.active_ant.rx;
+ rx_status->antenna = rt2x00dev->link.ant.active.rx;
/*
* Send frame to mac80211
diff --git a/drivers/net/wireless/rt2x00/rt2x00lib.h b/drivers/net/wireless/rt2x00/rt2x00lib.h
index 06d9bc0..7319411 100644
--- a/drivers/net/wireless/rt2x00/rt2x00lib.h
+++ b/drivers/net/wireless/rt2x00/rt2x00lib.h
@@ -53,6 +53,8 @@ void rt2x00lib_uninitialize(struct rt2x00_dev *rt2x00dev);
void rt2x00lib_config_mac_addr(struct rt2x00_dev *rt2x00dev, u8 *mac);
void rt2x00lib_config_bssid(struct rt2x00_dev *rt2x00dev, u8 *bssid);
void rt2x00lib_config_type(struct rt2x00_dev *rt2x00dev, const int type);
+void rt2x00lib_config_antenna(struct rt2x00_dev *rt2x00dev,
+ enum antenna rx, enum antenna tx);
void rt2x00lib_config(struct rt2x00_dev *rt2x00dev,
struct ieee80211_conf *conf, const int force_config);
--
1.5.3.4
-
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