ath9k: Remove dead code in rate control

ath9k rate control is based on only PER (packet error rate),
remove unused code which was intented to do rssi based rate
selection.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 159 deletions

diff --git a/drivers/net/wireless/ath/ath9k/rc.c b/drivers/net/wireless/ath/ath9k/rc.c
index e66734c2cae1..a39b1a7d3775 100644
--- a/drivers/net/wireless/ath/ath9k/rc.c
+++ b/drivers/net/wireless/ath/ath9k/rc.c
@@ -607,47 +607,14 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
                                  const struct ath_rate_table *rate_table,
                                  int *is_probing)
 {
-        u32 dt, best_thruput, this_thruput, now_msec;
+        u32 best_thruput, this_thruput, now_msec;
         u8 rate, next_rate, best_rate, maxindex, minindex;
-        int8_t  rssi_last, rssi_reduce = 0, index = 0;
-
-        *is_probing = 0;
-
-        rssi_last = median(ath_rc_priv->rssi_last,
-                           ath_rc_priv->rssi_last_prev,
-                           ath_rc_priv->rssi_last_prev2);
-
-        /*
-         * Age (reduce) last ack rssi based on how old it is.
-         * The bizarre numbers are so the delta is 160msec,
-         * meaning we divide by 16.
-         *   0msec   <= dt <= 25msec:   don't derate
-         *   25msec  <= dt <= 185msec:  derate linearly from 0 to 10dB
-         *   185msec <= dt:             derate by 10dB
-         */
+        int8_t index = 0;
 
         now_msec = jiffies_to_msecs(jiffies);
-        dt = now_msec - ath_rc_priv->rssi_time;
-
-        if (dt >= 185)
-                rssi_reduce = 10;
-        else if (dt >= 25)
-                rssi_reduce = (u8)((dt - 25) >> 4);
-
-        /* Now reduce rssi_last by rssi_reduce */
-        if (rssi_last < rssi_reduce)
-                rssi_last = 0;
-        else
-                rssi_last -= rssi_reduce;
-
-        /*
-         * Now look up the rate in the rssi table and return it.
-         * If no rates match then we return 0 (lowest rate)
-         */
-
+        *is_probing = 0;
         best_thruput = 0;
         maxindex = ath_rc_priv->max_valid_rate-1;
-
         minindex = 0;
         best_rate = minindex;
 
@@ -687,7 +654,6 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
         }
 
         rate = best_rate;
-        ath_rc_priv->rssi_last_lookup = rssi_last;
 
         /*
          * Must check the actual rate (ratekbps) to account for
@@ -977,10 +943,6 @@ static bool ath_rc_update_per(struct ath_softc *sc,
                                      (nretry_to_per_lookup[retries] >> 3));
                 }
 
-                ath_rc_priv->rssi_last_prev2 = ath_rc_priv->rssi_last_prev;
-                ath_rc_priv->rssi_last_prev  = ath_rc_priv->rssi_last;
-                ath_rc_priv->rssi_last = tx_info_priv->tx.ts_rssi;
-                ath_rc_priv->rssi_time = now_msec;
 
                 /*
                  * If we got at most one retry then increase the max rate if
@@ -1024,18 +986,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
                         /*
                          * Don't update anything.  We don't know if
                          * this was because of collisions or poor signal.
-                         *
-                         * Later: if rssi_ack is close to
-                         * ath_rc_priv->state[txRate].rssi_thres and we see lots
-                         * of retries, then we could increase
-                         * ath_rc_priv->state[txRate].rssi_thres.
                          */
                         ath_rc_priv->hw_maxretry_pktcnt = 0;
                 } else {
-                        int32_t rssi_ackAvg;
-                        int8_t rssi_thres;
-                        int8_t rssi_ack_vmin;
-
                         /*
                          * It worked with no retries. First ignore bogus (small)
                          * rssi_ack values.
@@ -1045,43 +998,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
                                 ath_rc_priv->hw_maxretry_pktcnt++;
                         }
 
-                        if (tx_info_priv->tx.ts_rssi <
-                            rate_table->info[tx_rate].rssi_ack_validmin)
-                                goto exit;
-
-                        /* Average the rssi */
-                        if (tx_rate != ath_rc_priv->rssi_sum_rate) {
-                                ath_rc_priv->rssi_sum_rate = tx_rate;
-                                ath_rc_priv->rssi_sum =
-                                        ath_rc_priv->rssi_sum_cnt = 0;
-                        }
-
-                        ath_rc_priv->rssi_sum += tx_info_priv->tx.ts_rssi;
-                        ath_rc_priv->rssi_sum_cnt++;
-
-                        if (ath_rc_priv->rssi_sum_cnt < 4)
-                                goto exit;
-
-                        rssi_ackAvg =
-                                (ath_rc_priv->rssi_sum + 2) / 4;
-                        rssi_thres =
-                                ath_rc_priv->state[tx_rate].rssi_thres;
-                        rssi_ack_vmin =
-                                rate_table->info[tx_rate].rssi_ack_validmin;
-
-                        ath_rc_priv->rssi_sum =
-                                ath_rc_priv->rssi_sum_cnt = 0;
-
-                        /* Now reduce the current rssi threshold */
-                        if ((rssi_ackAvg < rssi_thres + 2) &&
-                            (rssi_thres > rssi_ack_vmin)) {
-                                ath_rc_priv->state[tx_rate].rssi_thres--;
-                        }
-
-                        state_change = true;
                 }
         }
-exit:
+
         return state_change;
 }
 
@@ -1093,11 +1012,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
                              struct ath_tx_info_priv *tx_info_priv,
                              int tx_rate, int xretries, int retries)
 {
-#define CHK_RSSI(rate)                                  \
-        ((ath_rc_priv->state[(rate)].rssi_thres +       \
-          rate_table->info[(rate)].rssi_ack_deltamin) > \
-         ath_rc_priv->state[(rate)+1].rssi_thres)
-
         u32 now_msec = jiffies_to_msecs(jiffies);
         int rate;
         u8 last_per;
@@ -1108,13 +1022,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
         if ((tx_rate < 0) || (tx_rate > rate_table->rate_cnt))
                 return;
 
-        /* To compensate for some imbalance between ctrl and ext. channel */
-
-        if (WLAN_RC_PHY_40(rate_table->info[tx_rate].phy))
-                tx_info_priv->tx.ts_rssi =
-                        tx_info_priv->tx.ts_rssi < 3 ? 0 :
-                        tx_info_priv->tx.ts_rssi - 3;
-
         last_per = ath_rc_priv->state[tx_rate].per;
 
         /* Update PER first */
@@ -1136,51 +1043,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
                 ath_rc_priv->probe_time = now_msec;
         }
 
-        if (state_change) {
-                /*
-                 * Make sure the rates above this have higher rssi thresholds.
-                 * (Note:  Monotonicity is kept within the OFDM rates and
-                 *         within the CCK rates. However, no adjustment is
-                 *         made to keep the rssi thresholds monotonically
-                 *         increasing between the CCK and OFDM rates.)
-                 */
-                for (rate = tx_rate; rate < size - 1; rate++) {
-                        if (rate_table->info[rate+1].phy !=
-                            rate_table->info[tx_rate].phy)
-                                break;
-
-                        if (CHK_RSSI(rate)) {
-                                ath_rc_priv->state[rate+1].rssi_thres =
-                                        ath_rc_priv->state[rate].rssi_thres +
-                                        rate_table->info[rate].rssi_ack_deltamin;
-                        }
-                }
-
-                /* Make sure the rates below this have lower rssi thresholds. */
-                for (rate = tx_rate - 1; rate >= 0; rate--) {
-                        if (rate_table->info[rate].phy !=
-                            rate_table->info[tx_rate].phy)
-                                break;
-
-                        if (CHK_RSSI(rate)) {
-                                if (ath_rc_priv->state[rate+1].rssi_thres <
-                                    rate_table->info[rate].rssi_ack_deltamin)
-                                        ath_rc_priv->state[rate].rssi_thres = 0;
-                                else {
-                                        ath_rc_priv->state[rate].rssi_thres =
-                                        ath_rc_priv->state[rate+1].rssi_thres -
-                                        rate_table->info[rate].rssi_ack_deltamin;
-                                }
-
-                                if (ath_rc_priv->state[rate].rssi_thres <
-                                    rate_table->info[rate].rssi_ack_validmin) {
-                                        ath_rc_priv->state[rate].rssi_thres =
-                                        rate_table->info[rate].rssi_ack_validmin;
-                                }
-                        }
-                }
-        }
-
         /* Make sure the rates below this have lower PER */
         /* Monotonicity is kept only for rates below the current rate. */
         if (ath_rc_priv->state[tx_rate].per < last_per) {
@@ -1205,19 +1067,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
                                 ath_rc_priv->state[rate].per;
         }
 
-        /* Every so often, we reduce the thresholds and
-         * PER (different for CCK and OFDM). */
-        if (now_msec - ath_rc_priv->rssi_down_time >=
-            rate_table->rssi_reduce_interval) {
-
-                for (rate = 0; rate < size; rate++) {
-                        if (ath_rc_priv->state[rate].rssi_thres >
-                            rate_table->info[rate].rssi_ack_validmin)
-                                ath_rc_priv->state[rate].rssi_thres -= 1;
-                }
-                ath_rc_priv->rssi_down_time = now_msec;
-        }
-
         /* Every so often, we reduce the thresholds
          * and PER (different for CCK and OFDM). */
         if (now_msec - ath_rc_priv->per_down_time >=
@@ -1233,7 +1082,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
         ath_debug_stat_retries(sc, tx_rate, xretries, retries,
                                ath_rc_priv->state[tx_rate].per);
 
-#undef CHK_RSSI
 }
 
 static int ath_rc_get_rateindex(const struct ath_rate_table *rate_table,
@@ -1369,8 +1217,6 @@ static void ath_rc_init(struct ath_softc *sc,
 
         /* Initialize thresholds according to the global rate table */
         for (i = 0 ; i < ath_rc_priv->rate_table_size; i++) {
-                ath_rc_priv->state[i].rssi_thres =
-                        rate_table->info[i].rssi_ack_validmin;
                 ath_rc_priv->state[i].per = 0;
         }
 
@@ -1631,7 +1477,6 @@ static void *ath_rate_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp
                 return NULL;
         }
 
-        rate_priv->rssi_down_time = jiffies_to_msecs(jiffies);
         rate_priv->tx_triglevel_max = sc->sc_ah->caps.tx_triglevel_max;
 
         return rate_priv;