ath9k: Use calibrated noise floor value when available

AR9003 series allows to calibrate noise floor for different frequency
bins. Once it's done it's possible to get more accurate rssi/signal
values over whole frequency band at a given temperature.
The RSSI/signal accuracy reported by calibrated RF cards improves
from 6 to up to 2dB.

This could be interesting for application which require good signal
accuracy like roaming or mesh protocols.

Signed-off-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index 13ab6bc..3d9447e 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -58,19 +58,25 @@ static struct ath_nf_limits *ath9k_hw_get_nf_limits(struct ath_hw *ah,
 }
 
 static s16 ath9k_hw_get_default_nf(struct ath_hw *ah,
-                                  struct ath9k_channel *chan)
+                                  struct ath9k_channel *chan,
+                                  int chain)
 {
-       return ath9k_hw_get_nf_limits(ah, chan)->nominal;
+       s16 calib_nf = ath9k_hw_get_nf_limits(ah, chan)->cal[chain];
+
+       if (calib_nf)
+               return calib_nf;
+       else
+               return ath9k_hw_get_nf_limits(ah, chan)->nominal;
 }
 
 s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan,
                           s16 nf)
 {
-       s8 noise = ATH_DEFAULT_NOISE_FLOOR;
+       s8 noise = ath9k_hw_get_default_nf(ah, chan, 0);
 
        if (nf) {
                s8 delta = nf - ATH9K_NF_CAL_NOISE_THRESH -
-                          ath9k_hw_get_default_nf(ah, chan);
+                          ath9k_hw_get_default_nf(ah, chan, 0);
                if (delta > 0)
                        noise += delta;
        }
@@ -240,7 +246,7 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
        unsigned i, j;
        u8 chainmask = (ah->rxchainmask << 3) | ah->rxchainmask;
        struct ath_common *common = ath9k_hw_common(ah);
-       s16 default_nf = ath9k_hw_get_default_nf(ah, chan);
+       s16 default_nf = ath9k_hw_get_nf_limits(ah, chan)->nominal;
        u32 bb_agc_ctl = REG_READ(ah, AR_PHY_AGC_CONTROL);
 
        if (ah->caldata)
@@ -258,8 +264,13 @@ int ath9k_hw_loadnf(struct ath_hw *ah, struct ath9k_channel *chan)
                                nfval = ah->nf_override;
                        else if (h)
                                nfval = h[i].privNF;
-                       else
-                               nfval = default_nf;
+                       else {
+                               /* Try to get calibrated noise floor value */
+                               nfval =
+                                   ath9k_hw_get_nf_limits(ah, chan)->cal[i];
+                               if (nfval > -60 || nfval < -127)
+                                       nfval = default_nf;
+                       }
 
                        REG_RMW(ah, ah->nf_regs[i],
                                (((u32) nfval << 1) & 0x1ff), 0x1ff);
@@ -429,20 +440,19 @@ void ath9k_init_nfcal_hist_buffer(struct ath_hw *ah,
                                  struct ath9k_channel *chan)
 {
        struct ath9k_nfcal_hist *h;
-       s16 default_nf;
-       int i, j;
+       int i, j, k = 0;
 
        ah->caldata->channel = chan->channel;
        ah->caldata->channelFlags = chan->channelFlags;
        h = ah->caldata->nfCalHist;
-       default_nf = ath9k_hw_get_default_nf(ah, chan);
        for (i = 0; i < NUM_NF_READINGS; i++) {
                h[i].currIndex = 0;
-               h[i].privNF = default_nf;
+               h[i].privNF = ath9k_hw_get_default_nf(ah, chan, k);
                h[i].invalidNFcount = AR_PHY_CCA_FILTERWINDOW_LENGTH;
-               for (j = 0; j < ATH9K_NF_CAL_HIST_MAX; j++) {
-                       h[i].nfCalBuffer[j] = default_nf;
-               }
+               for (j = 0; j < ATH9K_NF_CAL_HIST_MAX; j++)
+                       h[i].nfCalBuffer[j] = h[i].privNF;
+               if (++k >= AR5416_MAX_CHAINS)
+                       k = 0;
        }
 }