rt2x00: use generic EWMA functions for average RSSI calculations
Remove the local MOVING_AVERAGE implementation, and use the generic EWMA functions instead. Signed-off-by: Gabor Juhos <juhosg@openwrt.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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@ -219,6 +219,7 @@ config RT2X00_LIB_USB
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config RT2X00_LIB
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config RT2X00_LIB
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tristate
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tristate
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select AVERAGE
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config RT2X00_LIB_FIRMWARE
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config RT2X00_LIB_FIRMWARE
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boolean
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boolean
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@ -39,6 +39,7 @@
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#include <linux/input-polldev.h>
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#include <linux/input-polldev.h>
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#include <linux/kfifo.h>
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#include <linux/kfifo.h>
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#include <linux/hrtimer.h>
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#include <linux/hrtimer.h>
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#include <linux/average.h>
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#include <net/mac80211.h>
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#include <net/mac80211.h>
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@ -138,17 +139,6 @@
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#define SHORT_EIFS ( SIFS + SHORT_DIFS + \
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#define SHORT_EIFS ( SIFS + SHORT_DIFS + \
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GET_DURATION(IEEE80211_HEADER + ACK_SIZE, 10) )
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GET_DURATION(IEEE80211_HEADER + ACK_SIZE, 10) )
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/*
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* Structure for average calculation
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* The avg field contains the actual average value,
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* but avg_weight is internally used during calculations
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* to prevent rounding errors.
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*/
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struct avg_val {
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int avg;
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int avg_weight;
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};
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enum rt2x00_chip_intf {
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enum rt2x00_chip_intf {
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RT2X00_CHIP_INTF_PCI,
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RT2X00_CHIP_INTF_PCI,
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RT2X00_CHIP_INTF_PCIE,
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RT2X00_CHIP_INTF_PCIE,
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@ -297,7 +287,7 @@ struct link_ant {
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* Similar to the avg_rssi in the link_qual structure
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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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* this value is updated by using the walking average.
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*/
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*/
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struct avg_val rssi_ant;
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struct ewma rssi_ant;
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};
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};
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/*
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/*
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@ -326,7 +316,7 @@ struct link {
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/*
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/*
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* Currently active average RSSI value
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* Currently active average RSSI value
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*/
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*/
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struct avg_val avg_rssi;
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struct ewma avg_rssi;
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/*
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/*
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* Work structure for scheduling periodic link tuning.
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* Work structure for scheduling periodic link tuning.
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@ -35,50 +35,28 @@
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*/
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*/
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#define DEFAULT_RSSI -128
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#define DEFAULT_RSSI -128
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/*
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/* Constants for EWMA calculations. */
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* Helper struct and macro to work with moving/walking averages.
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#define RT2X00_EWMA_FACTOR 1024
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* When adding a value to the average value the following calculation
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#define RT2X00_EWMA_WEIGHT 8
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* is needed:
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*
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static inline int rt2x00link_get_avg_rssi(struct ewma *ewma)
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* avg_rssi = ((avg_rssi * 7) + rssi) / 8;
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{
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*
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unsigned long avg;
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* The advantage of this approach is that we only need 1 variable
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* to store the average in (No need for a count and a total).
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avg = ewma_read(ewma);
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* But more importantly, normal average values will over time
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if (avg)
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* move less and less towards newly added values this results
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return -avg;
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* that with link tuning, the device can have a very good RSSI
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* for a few minutes but when the device is moved away from the AP
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return DEFAULT_RSSI;
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* the average will not decrease fast enough to compensate.
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}
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* The walking average compensates this and will move towards
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* the new values correctly allowing a effective link tuning,
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* the speed of the average moving towards other values depends
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* on the value for the number of samples. The higher the number
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* of samples, the slower the average will move.
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* We use two variables to keep track of the average value to
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* compensate for the rounding errors. This can be a significant
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* error (>5dBm) if the factor is too low.
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*/
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#define AVG_SAMPLES 8
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#define AVG_FACTOR 1000
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#define MOVING_AVERAGE(__avg, __val) \
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({ \
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struct avg_val __new; \
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__new.avg_weight = \
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(__avg).avg_weight ? \
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((((__avg).avg_weight * ((AVG_SAMPLES) - 1)) + \
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((__val) * (AVG_FACTOR))) / \
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(AVG_SAMPLES)) : \
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((__val) * (AVG_FACTOR)); \
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__new.avg = __new.avg_weight / (AVG_FACTOR); \
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__new; \
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})
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static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
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static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
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{
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{
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struct link_ant *ant = &rt2x00dev->link.ant;
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struct link_ant *ant = &rt2x00dev->link.ant;
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if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success)
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if (rt2x00dev->link.qual.rx_success)
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return ant->rssi_ant.avg;
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return rt2x00link_get_avg_rssi(&ant->rssi_ant);
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return DEFAULT_RSSI;
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return DEFAULT_RSSI;
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}
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}
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@ -100,8 +78,8 @@ static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
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static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
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static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
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{
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{
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rt2x00dev->link.ant.rssi_ant.avg = 0;
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ewma_init(&rt2x00dev->link.ant.rssi_ant, RT2X00_EWMA_FACTOR,
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rt2x00dev->link.ant.rssi_ant.avg_weight = 0;
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RT2X00_EWMA_WEIGHT);
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}
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}
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static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
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static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
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@ -249,12 +227,12 @@ void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
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/*
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/*
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* Update global RSSI
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* Update global RSSI
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*/
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*/
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link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi);
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ewma_add(&link->avg_rssi, -rxdesc->rssi);
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/*
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/*
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* Update antenna RSSI
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* Update antenna RSSI
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*/
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*/
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ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi);
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ewma_add(&ant->rssi_ant, -rxdesc->rssi);
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}
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}
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void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
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void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
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@ -309,6 +287,8 @@ void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
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*/
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*/
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rt2x00dev->link.count = 0;
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rt2x00dev->link.count = 0;
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memset(qual, 0, sizeof(*qual));
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memset(qual, 0, sizeof(*qual));
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ewma_init(&rt2x00dev->link.avg_rssi, RT2X00_EWMA_FACTOR,
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RT2X00_EWMA_WEIGHT);
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/*
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/*
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* Restore the VGC level as stored in the registers,
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* Restore the VGC level as stored in the registers,
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@ -363,10 +343,10 @@ static void rt2x00link_tuner(struct work_struct *work)
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* collect the RSSI data we could use this. Otherwise we
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* collect the RSSI data we could use this. Otherwise we
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* must fallback to the default RSSI value.
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* must fallback to the default RSSI value.
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*/
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*/
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if (!link->avg_rssi.avg || !qual->rx_success)
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if (!qual->rx_success)
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qual->rssi = DEFAULT_RSSI;
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qual->rssi = DEFAULT_RSSI;
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else
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else
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qual->rssi = link->avg_rssi.avg;
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qual->rssi = rt2x00link_get_avg_rssi(&link->avg_rssi);
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/*
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/*
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* Check if link tuning is supported by the hardware, some hardware
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* Check if link tuning is supported by the hardware, some hardware
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