diff options
Diffstat (limited to 'drivers/net/wireless/rt2x00')
| -rw-r--r-- | drivers/net/wireless/rt2x00/rt2x00.h | 15 | ||||
| -rw-r--r-- | drivers/net/wireless/rt2x00/rt2x00link.c | 65 |
2 files changed, 52 insertions, 28 deletions
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h index 704e94474b1d..e6e73be31e37 100644 --- a/drivers/net/wireless/rt2x00/rt2x00.h +++ b/drivers/net/wireless/rt2x00/rt2x00.h @@ -134,6 +134,17 @@ 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; +}; + +/* * Chipset identification * The chipset on the device is composed of a RT and RF chip. * The chipset combination is important for determining device capabilities. @@ -256,7 +267,7 @@ struct link_ant { * Similar to the avg_rssi in the link_qual structure * this value is updated by using the walking average. */ - int rssi_ant; + struct avg_val rssi_ant; }; /* @@ -285,7 +296,7 @@ struct link { /* * Currently active average RSSI value */ - int avg_rssi; + struct avg_val avg_rssi; /* * Currently precalculated percentages of successful diff --git a/drivers/net/wireless/rt2x00/rt2x00link.c b/drivers/net/wireless/rt2x00/rt2x00link.c index dd68f3a57b6d..c64db0ba7f40 100644 --- a/drivers/net/wireless/rt2x00/rt2x00link.c +++ b/drivers/net/wireless/rt2x00/rt2x00link.c @@ -46,7 +46,15 @@ #define DEFAULT_PERCENTAGE 50 /* - * Small helper macro to work with moving/walking averages. + * Small helper macro for percentage calculation + * This is a very simple macro with the only catch that it will + * produce a default value in case no total value was provided. + */ +#define PERCENTAGE(__value, __total) \ + ( (__total) ? (((__value) * 100) / (__total)) : (DEFAULT_PERCENTAGE) ) + +/* + * Helper struct and macro to work with moving/walking averages. * When adding a value to the average value the following calculation * is needed: * @@ -60,18 +68,28 @@ * 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 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 MOVING_AVERAGE(__avg, __val, __samples) \ - ( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) ) - -/* - * Small helper macro for percentage calculation - * This is a very simple macro with the only catch that it will - * produce a default value in case no total value was provided. - */ -#define PERCENTAGE(__value, __total) \ - ( (__total) ? (((__value) * 100) / (__total)) : (DEFAULT_PERCENTAGE) ) +#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; \ +}) /* * For calculating the Signal quality we have determined @@ -98,8 +116,8 @@ static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev) { struct link_ant *ant = &rt2x00dev->link.ant; - if (ant->rssi_ant && rt2x00dev->link.qual.rx_success) - return ant->rssi_ant; + if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success) + return ant->rssi_ant.avg; return DEFAULT_RSSI; } @@ -121,7 +139,8 @@ 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 = 0; + rt2x00dev->link.ant.rssi_ant.avg = 0; + rt2x00dev->link.ant.rssi_ant.avg_weight = 0; } static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev) @@ -258,8 +277,6 @@ void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev, struct link_qual *qual = &rt2x00dev->link.qual; struct link_ant *ant = &rt2x00dev->link.ant; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; - int avg_rssi = rxdesc->rssi; - int ant_rssi = rxdesc->rssi; /* * Frame was received successfully since non-succesfull @@ -279,16 +296,12 @@ void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev, /* * Update global RSSI */ - if (link->avg_rssi) - avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi, 8); - link->avg_rssi = avg_rssi; + link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi); /* * Update antenna RSSI */ - if (ant->rssi_ant) - ant_rssi = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi, 8); - ant->rssi_ant = ant_rssi; + ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi); } static void rt2x00link_precalculate_signal(struct rt2x00_dev *rt2x00dev) @@ -421,10 +434,10 @@ 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 || !qual->rx_success) + if (!link->avg_rssi.avg || !qual->rx_success) qual->rssi = DEFAULT_RSSI; else - qual->rssi = link->avg_rssi; + qual->rssi = link->avg_rssi.avg; /* * Only perform the link tuning when Link tuning @@ -442,7 +455,7 @@ static void rt2x00link_tuner(struct work_struct *work) /* * Send a signal to the led to update the led signal strength. */ - rt2x00leds_led_quality(rt2x00dev, link->avg_rssi); + rt2x00leds_led_quality(rt2x00dev, qual->rssi); /* * Evaluate antenna setup, make this the last step when |