iwlwifi: clean up rs_tx_status
authorDaniel C Halperin <daniel.c.halperin@intel.com>
Thu, 17 Sep 2009 17:43:48 +0000 (10:43 -0700)
committerJohn W. Linville <linville@tuxdriver.com>
Wed, 7 Oct 2009 20:39:34 +0000 (16:39 -0400)
Cut down on redundant code, reorganize structure, and add/improve comments.
Should contain no functional changes.

Signed-off-by: Daniel C Halperin <daniel.c.halperin@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
drivers/net/wireless/iwlwifi/iwl-agn-rs.c

index 469d56321d88bd5697647523947a632d40d0aaee..cd24763d5fde3f13477c75f5c32a776797f0067f 100644 (file)
@@ -820,6 +820,26 @@ out:
        return rate_n_flags_from_tbl(lq_sta->drv, tbl, low, is_green);
 }
 
+/*
+ * Simple function to compare two rate scale table types
+ */
+static bool table_type_matches(struct iwl_scale_tbl_info *a,
+                              struct iwl_scale_tbl_info *b)
+{
+       return (a->lq_type == b->lq_type) && (a->ant_type == b->ant_type) &&
+               (a->is_SGI == b->is_SGI);
+}
+/*
+ * Static function to get the expected throughput from an iwl_scale_tbl_info
+ * that wraps a NULL pointer check
+ */
+static s32 get_expected_tpt(struct iwl_scale_tbl_info *tbl, int rs_index)
+{
+       if (tbl->expected_tpt)
+               return tbl->expected_tpt[rs_index];
+       return 0;
+}
+
 /*
  * mac80211 sends us Tx status
  */
@@ -827,21 +847,19 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
                         struct ieee80211_sta *sta, void *priv_sta,
                         struct sk_buff *skb)
 {
-       int status;
-       u8 retries;
-       int rs_index, mac_index, index = 0;
+       int legacy_success;
+       int retries;
+       int rs_index, mac_index, i;
        struct iwl_lq_sta *lq_sta = priv_sta;
        struct iwl_link_quality_cmd *table;
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
        struct iwl_priv *priv = (struct iwl_priv *)priv_r;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        struct iwl_rate_scale_data *window = NULL;
-       struct iwl_rate_scale_data *search_win = NULL;
        enum mac80211_rate_control_flags mac_flags;
        u32 tx_rate;
        struct iwl_scale_tbl_info tbl_type;
-       struct iwl_scale_tbl_info *curr_tbl, *search_tbl;
-       u8 active_index = 0;
+       struct iwl_scale_tbl_info *curr_tbl, *other_tbl;
        s32 tpt = 0;
 
        IWL_DEBUG_RATE_LIMIT(priv, "get frame ack response, update rate scale window\n");
@@ -855,25 +873,10 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
            !(info->flags & IEEE80211_TX_STAT_AMPDU))
                return;
 
-       if (info->flags & IEEE80211_TX_STAT_AMPDU)
-               retries = 0;
-       else
-               retries = info->status.rates[0].count - 1;
-
-       if (retries > 15)
-               retries = 15;
 
        if ((priv->iw_mode == NL80211_IFTYPE_ADHOC) &&
            !lq_sta->ibss_sta_added)
-               goto out;
-
-       table = &lq_sta->lq;
-       active_index = lq_sta->active_tbl;
-
-       curr_tbl = &(lq_sta->lq_info[active_index]);
-       search_tbl = &(lq_sta->lq_info[(1 - active_index)]);
-       window = (struct iwl_rate_scale_data *)&(curr_tbl->win[0]);
-       search_win = (struct iwl_rate_scale_data *)&(search_tbl->win[0]);
+               return;
 
        /*
         * Ignore this Tx frame response if its initial rate doesn't match
@@ -883,6 +886,7 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
         * to check "search" mode, or a prior "search" mode after we've moved
         * to a new "search" mode (which might become the new "active" mode).
         */
+       table = &lq_sta->lq;
        tx_rate = le32_to_cpu(table->rs_table[0].rate_n_flags);
        rs_get_tbl_info_from_mcs(tx_rate, priv->band, &tbl_type, &rs_index);
        if (priv->band == IEEE80211_BAND_5GHZ)
@@ -901,7 +905,7 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
                if (priv->band == IEEE80211_BAND_2GHZ)
                        mac_index += IWL_FIRST_OFDM_RATE;
        }
-
+       /* Here we actually compare this rate to the latest LQ command */
        if ((mac_index < 0) ||
            (tbl_type.is_SGI != !!(mac_flags & IEEE80211_TX_RC_SHORT_GI)) ||
            (tbl_type.is_ht40 != !!(mac_flags & IEEE80211_TX_RC_40_MHZ_WIDTH)) ||
@@ -911,124 +915,106 @@ static void rs_tx_status(void *priv_r, struct ieee80211_supported_band *sband,
            (!!(tx_rate & RATE_MCS_GF_MSK) != !!(mac_flags & IEEE80211_TX_RC_GREEN_FIELD)) ||
            (rs_index != mac_index)) {
                IWL_DEBUG_RATE(priv, "initial rate %d does not match %d (0x%x)\n", mac_index, rs_index, tx_rate);
-               /* the last LQ command could failed so the LQ in ucode not
-                * the same in driver sync up
+               /*
+                * Since rates mis-match, the last LQ command may have failed.
+                * After IWL_MISSED_RATE_MAX mis-matches, resync the uCode with
+                * ... driver.
                 */
                lq_sta->missed_rate_counter++;
                if (lq_sta->missed_rate_counter > IWL_MISSED_RATE_MAX) {
                        lq_sta->missed_rate_counter = 0;
                        iwl_send_lq_cmd(priv, &lq_sta->lq, CMD_ASYNC);
                }
-               goto out;
+               /* Regardless, ignore this status info for outdated rate */
+               return;
+       } else
+               /* Rate did match, so reset the missed_rate_counter */
+               lq_sta->missed_rate_counter = 0;
+
+       /* Figure out if rate scale algorithm is in active or search table */
+       if (table_type_matches(&tbl_type,
+                               &(lq_sta->lq_info[lq_sta->active_tbl]))) {
+               curr_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
+               other_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
+       } else if (table_type_matches(&tbl_type,
+                               &lq_sta->lq_info[1 - lq_sta->active_tbl])) {
+               curr_tbl = &(lq_sta->lq_info[1 - lq_sta->active_tbl]);
+               other_tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
+       } else {
+               IWL_DEBUG_RATE(priv, "Neither active nor search matches tx rate\n");
+               return;
        }
+       window = (struct iwl_rate_scale_data *)&(curr_tbl->win[0]);
 
-       lq_sta->missed_rate_counter = 0;
-       /* Update frame history window with "failure" for each Tx retry. */
-       while (retries) {
-               /* Look up the rate and other info used for each tx attempt.
-                * Each tx attempt steps one entry deeper in the rate table. */
-               tx_rate = le32_to_cpu(table->rs_table[index].rate_n_flags);
-               rs_get_tbl_info_from_mcs(tx_rate, priv->band,
-                                         &tbl_type, &rs_index);
-
-               /* If type matches "search" table,
-                * add failure to "search" history */
-               if ((tbl_type.lq_type == search_tbl->lq_type) &&
-                   (tbl_type.ant_type == search_tbl->ant_type) &&
-                   (tbl_type.is_SGI == search_tbl->is_SGI)) {
-                       if (search_tbl->expected_tpt)
-                               tpt = search_tbl->expected_tpt[rs_index];
-                       else
-                               tpt = 0;
-                       rs_collect_tx_data(search_win, rs_index, tpt, 1, 0);
-
-               /* Else if type matches "current/active" table,
-                * add failure to "current/active" history */
-               } else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
-                          (tbl_type.ant_type == curr_tbl->ant_type) &&
-                          (tbl_type.is_SGI == curr_tbl->is_SGI)) {
-                       if (curr_tbl->expected_tpt)
-                               tpt = curr_tbl->expected_tpt[rs_index];
-                       else
-                               tpt = 0;
-                       rs_collect_tx_data(window, rs_index, tpt, 1, 0);
+       /*
+        * Updating the frame history depends on whether packets were
+        * aggregated.
+        *
+        * For aggregation, all packets were transmitted at the same rate, the
+        * first index into rate scale table.
+        */
+       if (info->flags & IEEE80211_TX_STAT_AMPDU) {
+               tx_rate = le32_to_cpu(table->rs_table[0].rate_n_flags);
+               rs_get_tbl_info_from_mcs(tx_rate, priv->band, &tbl_type,
+                               &rs_index);
+               tpt = get_expected_tpt(curr_tbl, rs_index);
+               rs_collect_tx_data(window, rs_index, tpt,
+                                  info->status.ampdu_ack_len,
+                                  info->status.ampdu_ack_map);
+
+               /* Update success/fail counts if not searching for new mode */
+               if (lq_sta->stay_in_tbl) {
+                       lq_sta->total_success += info->status.ampdu_ack_map;
+                       lq_sta->total_failed += (info->status.ampdu_ack_len -
+                                       info->status.ampdu_ack_map);
                }
-
-               /* If not searching for a new mode, increment failed counter
-                * ... this helps determine when to start searching again */
-               if (lq_sta->stay_in_tbl)
-                       lq_sta->total_failed++;
-               --retries;
-               index++;
-
-       }
-
+       } else {
        /*
-        * Find (by rate) the history window to update with final Tx attempt;
-        * if Tx was successful first try, use original rate,
-        * else look up the rate that was, finally, successful.
+        * For legacy, update frame history with for each Tx retry.
         */
-       tx_rate = le32_to_cpu(table->rs_table[index].rate_n_flags);
-       lq_sta->last_rate_n_flags = tx_rate;
-       rs_get_tbl_info_from_mcs(tx_rate, priv->band, &tbl_type, &rs_index);
-
-       /* Update frame history window with "success" if Tx got ACKed ... */
-       status = !!(info->flags & IEEE80211_TX_STAT_ACK);
-
-       /* If type matches "search" table,
-        * add final tx status to "search" history */
-       if ((tbl_type.lq_type == search_tbl->lq_type) &&
-           (tbl_type.ant_type == search_tbl->ant_type) &&
-           (tbl_type.is_SGI == search_tbl->is_SGI)) {
-               if (search_tbl->expected_tpt)
-                       tpt = search_tbl->expected_tpt[rs_index];
-               else
-                       tpt = 0;
-               if (info->flags & IEEE80211_TX_STAT_AMPDU)
-                       rs_collect_tx_data(search_win, rs_index, tpt,
-                                          info->status.ampdu_ack_len,
-                                          info->status.ampdu_ack_map);
-               else
-                       rs_collect_tx_data(search_win, rs_index, tpt,
-                                          1, status);
-       /* Else if type matches "current/active" table,
-        * add final tx status to "current/active" history */
-       } else if ((tbl_type.lq_type == curr_tbl->lq_type) &&
-                  (tbl_type.ant_type == curr_tbl->ant_type) &&
-                  (tbl_type.is_SGI == curr_tbl->is_SGI)) {
-               if (curr_tbl->expected_tpt)
-                       tpt = curr_tbl->expected_tpt[rs_index];
-               else
-                       tpt = 0;
-               if (info->flags & IEEE80211_TX_STAT_AMPDU)
-                       rs_collect_tx_data(window, rs_index, tpt,
-                                          info->status.ampdu_ack_len,
-                                          info->status.ampdu_ack_map);
-               else
-                       rs_collect_tx_data(window, rs_index, tpt,
-                                          1, status);
-       }
+               retries = info->status.rates[0].count - 1;
+               /* HW doesn't send more than 15 retries */
+               retries = min(retries, 15);
+
+               /* The last transmission may have been successful */
+               legacy_success = !!(info->flags & IEEE80211_TX_STAT_ACK);
+               /* Collect data for each rate used during failed TX attempts */
+               for (i = 0; i <= retries; ++i) {
+                       tx_rate = le32_to_cpu(table->rs_table[i].rate_n_flags);
+                       rs_get_tbl_info_from_mcs(tx_rate, priv->band,
+                                       &tbl_type, &rs_index);
+                       /*
+                        * Only collect stats if retried rate is in the same RS
+                        * table as active/search.
+                        */
+                       if (table_type_matches(&tbl_type, curr_tbl))
+                               tpt = get_expected_tpt(curr_tbl, rs_index);
+                       else if (table_type_matches(&tbl_type, other_tbl))
+                               tpt = get_expected_tpt(other_tbl, rs_index);
+                       else
+                               continue;
 
-       /* If not searching for new mode, increment success/failed counter
-        * ... these help determine when to start searching again */
-       if (lq_sta->stay_in_tbl) {
-               if (info->flags & IEEE80211_TX_STAT_AMPDU) {
-                       lq_sta->total_success += info->status.ampdu_ack_map;
-                       lq_sta->total_failed +=
-                            (info->status.ampdu_ack_len - info->status.ampdu_ack_map);
-               } else {
-                       if (status)
-                               lq_sta->total_success++;
+                       /* Constants mean 1 transmission, 0 successes */
+                       if (i < retries)
+                               rs_collect_tx_data(window, rs_index, tpt, 1,
+                                               0);
                        else
-                               lq_sta->total_failed++;
+                               rs_collect_tx_data(window, rs_index, tpt, 1,
+                                               legacy_success);
+               }
+
+               /* Update success/fail counts if not searching for new mode */
+               if (lq_sta->stay_in_tbl) {
+                       lq_sta->total_success += legacy_success;
+                       lq_sta->total_failed += retries + (1 - legacy_success);
                }
        }
+       /* The last TX rate is cached in lq_sta; it's set in if/else above */
+       lq_sta->last_rate_n_flags = tx_rate;
 
        /* See if there's a better rate or modulation mode to try. */
        if (sta && sta->supp_rates[sband->band])
                rs_rate_scale_perform(priv, skb, sta, lq_sta);
-out:
-       return;
 }
 
 /*