ath9k: Handle mac80211's RC flags for MCS rates

mac80211 notifies the RC algorithm if RTS/CTS and short preamble
are needed. The RC flags for MCS rates are currently not handled
by mac80211, and ath9k's RC doesn't set the flags either. Fix this.

Also, set the rts_cts_rate_idx inside the RC algorithm.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 71 insertions, 11 deletions

diff --git a/drivers/net/wireless/ath9k/rc.c b/drivers/net/wireless/ath9k/rc.c
index 8bc7bb50c7fc..a8c4f9757eb1 100644
--- a/drivers/net/wireless/ath9k/rc.c
+++ b/drivers/net/wireless/ath9k/rc.c
@@ -747,14 +747,17 @@ static u8 ath_rc_ratefind_ht(struct ath_softc *sc,
         return rate;
 }
 
-static void ath_rc_rate_set_series(struct ath_rate_table *rate_table ,
+static void ath_rc_rate_set_series(struct ath_rate_table *rate_table,
                                    struct ieee80211_tx_rate *rate,
+                                   struct ieee80211_tx_rate_control *txrc,
                                    u8 tries, u8 rix, int rtsctsenable)
 {
         rate->count = tries;
         rate->idx = rix;
 
-        if (rtsctsenable)
+        if (txrc->short_preamble)
+                rate->flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
+        if (txrc->rts || rtsctsenable)
                 rate->flags |= IEEE80211_TX_RC_USE_RTS_CTS;
         if (WLAN_RC_PHY_40(rate_table->info[rix].phy))
                 rate->flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
@@ -764,6 +767,43 @@ static void ath_rc_rate_set_series(struct ath_rate_table *rate_table ,
                 rate->flags |= IEEE80211_TX_RC_MCS;
 }
 
+static void ath_rc_rate_set_rtscts(struct ath_softc *sc,
+                                   struct ath_rate_table *rate_table,
+                                   struct ieee80211_tx_info *tx_info)
+{
+        struct ieee80211_tx_rate *rates = tx_info->control.rates;
+        int i = 0, rix = 0, cix, enable_g_protection = 0;
+
+        /* get the cix for the lowest valid rix */
+        for (i = 3; i >= 0; i--) {
+                if (rates[i].count && (rates[i].idx >= 0)) {
+                        rix = rates[i].idx;
+                        break;
+                }
+        }
+        cix = rate_table->info[rix].ctrl_rate;
+
+        /* All protection frames are transmited at 2Mb/s for 802.11g,
+         * otherwise we transmit them at 1Mb/s */
+        if (sc->hw->conf.channel->band == IEEE80211_BAND_2GHZ &&
+            !conf_is_ht(&sc->hw->conf))
+                enable_g_protection = 1;
+
+        /*
+         * If 802.11g protection is enabled, determine whether to use RTS/CTS or
+         * just CTS.  Note that this is only done for OFDM/HT unicast frames.
+         */
+        if ((sc->sc_flags & SC_OP_PROTECT_ENABLE) &&
+            !(tx_info->flags & IEEE80211_TX_CTL_NO_ACK) &&
+            (rate_table->info[rix].phy == WLAN_RC_PHY_OFDM ||
+             WLAN_RC_PHY_HT(rate_table->info[rix].phy))) {
+                rates[0].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
+                cix = rate_table->info[enable_g_protection].ctrl_rate;
+        }
+
+        tx_info->control.rts_cts_rate_idx = cix;
+}
+
 static u8 ath_rc_rate_getidx(struct ath_softc *sc,
                              struct ath_rate_priv *ath_rc_priv,
                              struct ath_rate_table *rate_table,
@@ -801,6 +841,8 @@ static void ath_rc_ratefind(struct ath_softc *sc,
         struct sk_buff *skb = txrc->skb;
         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
         struct ieee80211_tx_rate *rates = tx_info->control.rates;
+        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+        __le16 fc = hdr->frame_control;
         u8 try_per_rate = 0, i = 0, rix, nrix;
         int is_probe = 0;
 
@@ -811,7 +853,7 @@ static void ath_rc_ratefind(struct ath_softc *sc,
         if (is_probe) {
                 /* set one try for probe rates. For the
                  * probes don't enable rts */
-                ath_rc_rate_set_series(rate_table, &rates[i++],
+                ath_rc_rate_set_series(rate_table, &rates[i++], txrc,
                                        1, nrix, 0);
 
                 try_per_rate = (ATH_11N_TXMAXTRY/4);
@@ -820,12 +862,12 @@ static void ath_rc_ratefind(struct ath_softc *sc,
                  */
                 nrix = ath_rc_rate_getidx(sc, ath_rc_priv,
                                           rate_table, nrix, 1, 0);
-                ath_rc_rate_set_series(rate_table, &rates[i++],
+                ath_rc_rate_set_series(rate_table, &rates[i++], txrc,
                                        try_per_rate, nrix, 0);
         } else {
                 try_per_rate = (ATH_11N_TXMAXTRY/4);
                 /* Set the choosen rate. No RTS for first series entry. */
-                ath_rc_rate_set_series(rate_table, &rates[i++],
+                ath_rc_rate_set_series(rate_table, &rates[i++], txrc,
                                        try_per_rate, nrix, 0);
         }
 
@@ -841,7 +883,7 @@ static void ath_rc_ratefind(struct ath_softc *sc,
                 nrix = ath_rc_rate_getidx(sc, ath_rc_priv,
                                           rate_table, nrix, 1, min_rate);
                 /* All other rates in the series have RTS enabled */
-                ath_rc_rate_set_series(rate_table, &rates[i],
+                ath_rc_rate_set_series(rate_table, &rates[i], txrc,
                                        try_num, nrix, 1);
         }
 
@@ -871,6 +913,24 @@ static void ath_rc_ratefind(struct ath_softc *sc,
                         rates[3].flags = rates[2].flags;
                 }
         }
+
+        /*
+         * Force hardware to use computed duration for next
+         * fragment by disabling multi-rate retry, which
+         * updates duration based on the multi-rate duration table.
+         *
+         * FIXME: Fix duration
+         */
+        if (!(tx_info->flags & IEEE80211_TX_CTL_NO_ACK) &&
+            (ieee80211_has_morefrags(fc) ||
+             (le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG))) {
+                rates[1].count = rates[2].count = rates[3].count = 0;
+                rates[1].idx = rates[2].idx = rates[3].idx = 0;
+                rates[0].count = ATH_TXMAXTRY;
+        }
+
+        /* Setup RTS/CTS */
+        ath_rc_rate_set_rtscts(sc, rate_table, tx_info);
 }
 
 static bool ath_rc_update_per(struct ath_softc *sc,
@@ -1385,16 +1445,16 @@ static void ath_rc_init(struct ath_softc *sc,
         if (!rateset->rs_nrates) {
                 /* No working rate, just initialize valid rates */
                 hi = ath_rc_init_validrates(ath_rc_priv, rate_table,
-                                                ath_rc_priv->ht_cap);
+                                            ath_rc_priv->ht_cap);
         } else {
                 /* Use intersection of working rates and valid rates */
                 hi = ath_rc_setvalid_rates(ath_rc_priv, rate_table,
-                                               rateset, ath_rc_priv->ht_cap);
+                                           rateset, ath_rc_priv->ht_cap);
                 if (ath_rc_priv->ht_cap & WLAN_RC_HT_FLAG) {
                         hthi = ath_rc_setvalid_htrates(ath_rc_priv,
-                                                           rate_table,
-                                                           ht_mcs,
-                                                           ath_rc_priv->ht_cap);
+                                                       rate_table,
+                                                       ht_mcs,
+                                                       ath_rc_priv->ht_cap);
                 }
                 hi = A_MAX(hi, hthi);
         }