diff options
author | Gabor Juhos <juhosg@openwrt.org> | 2013-10-09 11:00:38 +0200 |
---|---|---|
committer | John W. Linville <linville@tuxdriver.com> | 2013-10-10 13:49:29 -0400 |
commit | 1dc254ac9f04f23d332ed8eea79055f067c90627 (patch) | |
tree | cbadcc1ab4c37dae2d5856f98fa3245346bbca31 /drivers/net/wireless | |
parent | 8f78b0bb8791d8164aed86970905cdc12f3b8496 (diff) |
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>
Diffstat (limited to 'drivers/net/wireless')
-rw-r--r-- | drivers/net/wireless/rt2x00/Kconfig | 1 | ||||
-rw-r--r-- | drivers/net/wireless/rt2x00/rt2x00.h | 16 | ||||
-rw-r--r-- | drivers/net/wireless/rt2x00/rt2x00link.c | 70 |
3 files changed, 29 insertions, 58 deletions
diff --git a/drivers/net/wireless/rt2x00/Kconfig b/drivers/net/wireless/rt2x00/Kconfig index 68dbbb9c6d1..a18b0051a74 100644 --- a/drivers/net/wireless/rt2x00/Kconfig +++ b/drivers/net/wireless/rt2x00/Kconfig @@ -219,6 +219,7 @@ config RT2X00_LIB_USB config RT2X00_LIB tristate + select AVERAGE config RT2X00_LIB_FIRMWARE boolean diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h index fe4c572db52..30ed92a6121 100644 --- a/drivers/net/wireless/rt2x00/rt2x00.h +++ b/drivers/net/wireless/rt2x00/rt2x00.h @@ -39,6 +39,7 @@ #include <linux/input-polldev.h> #include <linux/kfifo.h> #include <linux/hrtimer.h> +#include <linux/average.h> #include <net/mac80211.h> @@ -138,17 +139,6 @@ #define SHORT_EIFS ( SIFS + SHORT_DIFS + \ GET_DURATION(IEEE80211_HEADER + ACK_SIZE, 10) ) -/* - * Structure for average calculation - * The avg field contains the actual average value, - * but avg_weight is internally used during calculations - * to prevent rounding errors. - */ -struct avg_val { - int avg; - int avg_weight; -}; - enum rt2x00_chip_intf { RT2X00_CHIP_INTF_PCI, RT2X00_CHIP_INTF_PCIE, @@ -297,7 +287,7 @@ struct link_ant { * Similar to the avg_rssi in the link_qual structure * this value is updated by using the walking average. */ - struct avg_val rssi_ant; + struct ewma rssi_ant; }; /* @@ -326,7 +316,7 @@ struct link { /* * Currently active average RSSI value */ - struct avg_val avg_rssi; + struct ewma avg_rssi; /* * Work structure for scheduling periodic link tuning. diff --git a/drivers/net/wireless/rt2x00/rt2x00link.c b/drivers/net/wireless/rt2x00/rt2x00link.c index 8368aab86f2..a0e3c021c12 100644 --- a/drivers/net/wireless/rt2x00/rt2x00link.c +++ b/drivers/net/wireless/rt2x00/rt2x00link.c @@ -35,50 +35,28 @@ */ #define DEFAULT_RSSI -128 -/* - * Helper struct and macro to work with moving/walking averages. - * When adding a value to the average value the following calculation - * is needed: - * - * avg_rssi = ((avg_rssi * 7) + rssi) / 8; - * - * The advantage of this approach is that we only need 1 variable - * to store the average in (No need for a count and a total). - * But more importantly, normal average values will over time - * move less and less towards newly added values this results - * that with link tuning, the device can have a very good RSSI - * for a few minutes but when the device is moved away from the AP - * the average will not decrease fast enough to compensate. - * The walking average compensates this and will move towards - * the new values correctly allowing a effective link tuning, - * the speed of the average moving towards other values depends - * on the value for the number of samples. The higher the number - * of samples, the slower the average will move. - * We use two variables to keep track of the average value to - * compensate for the rounding errors. This can be a significant - * error (>5dBm) if the factor is too low. - */ -#define AVG_SAMPLES 8 -#define AVG_FACTOR 1000 -#define MOVING_AVERAGE(__avg, __val) \ -({ \ - struct avg_val __new; \ - __new.avg_weight = \ - (__avg).avg_weight ? \ - ((((__avg).avg_weight * ((AVG_SAMPLES) - 1)) + \ - ((__val) * (AVG_FACTOR))) / \ - (AVG_SAMPLES)) : \ - ((__val) * (AVG_FACTOR)); \ - __new.avg = __new.avg_weight / (AVG_FACTOR); \ - __new; \ -}) +/* Constants for EWMA calculations. */ +#define RT2X00_EWMA_FACTOR 1024 +#define RT2X00_EWMA_WEIGHT 8 + +static inline int rt2x00link_get_avg_rssi(struct ewma *ewma) +{ + unsigned long avg; + + avg = ewma_read(ewma); + if (avg) + return -avg; + + return DEFAULT_RSSI; +} static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev) { struct link_ant *ant = &rt2x00dev->link.ant; - if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success) - return ant->rssi_ant.avg; + if (rt2x00dev->link.qual.rx_success) + return rt2x00link_get_avg_rssi(&ant->rssi_ant); + return DEFAULT_RSSI; } @@ -100,8 +78,8 @@ static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev, static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev) { - rt2x00dev->link.ant.rssi_ant.avg = 0; - rt2x00dev->link.ant.rssi_ant.avg_weight = 0; + ewma_init(&rt2x00dev->link.ant.rssi_ant, RT2X00_EWMA_FACTOR, + RT2X00_EWMA_WEIGHT); } static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev) @@ -249,12 +227,12 @@ void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev, /* * Update global RSSI */ - link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi); + ewma_add(&link->avg_rssi, -rxdesc->rssi); /* * Update antenna RSSI */ - ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi); + ewma_add(&ant->rssi_ant, -rxdesc->rssi); } void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev) @@ -309,6 +287,8 @@ void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna) */ rt2x00dev->link.count = 0; memset(qual, 0, sizeof(*qual)); + ewma_init(&rt2x00dev->link.avg_rssi, RT2X00_EWMA_FACTOR, + RT2X00_EWMA_WEIGHT); /* * Restore the VGC level as stored in the registers, @@ -363,10 +343,10 @@ static void rt2x00link_tuner(struct work_struct *work) * collect the RSSI data we could use this. Otherwise we * must fallback to the default RSSI value. */ - if (!link->avg_rssi.avg || !qual->rx_success) + if (!qual->rx_success) qual->rssi = DEFAULT_RSSI; else - qual->rssi = link->avg_rssi.avg; + qual->rssi = rt2x00link_get_avg_rssi(&link->avg_rssi); /* * Check if link tuning is supported by the hardware, some hardware |