iwlwifi: mvm: rs: start using LQ command color

Up until now, the driver was comparing the rate reported by the FW and
the rate of the latest LQ command to avoid processing data belonging
to the old LQ command. Recently, FW changed the meaning of the initial
rate field in tx response and it holds the actual rate (which is not
necessarily the initial rate of LQ's rate table). Use instead LQ cmd
color to be able to filter out tx responses/BA notifications which
where sent during earlier LQ commands' time frame.

This fixes some throughput degradation in noisy environments.

Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

1 files changed, 11 insertions, 35 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
index 7788eefcd2bd..aa785cf3cf68 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/rs.c
@@ -2,7 +2,7 @@
  *
  * Copyright(c) 2005 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
- * Copyright(c) 2016 Intel Deutschland GmbH
+ * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2 of the GNU General Public License as
@@ -1083,34 +1083,6 @@ static void rs_get_lower_rate_down_column(struct iwl_lq_sta *lq_sta,
 		rs_get_lower_rate_in_column(lq_sta, rate);
 }
 
-/* Check if both rates are identical
- * allow_ant_mismatch enables matching a SISO rate on ANT_A or ANT_B
- * with a rate indicating STBC/BFER and ANT_AB.
- */
-static inline bool rs_rate_equal(struct rs_rate *a,
-				 struct rs_rate *b,
-				 bool allow_ant_mismatch)
-
-{
-	bool ant_match = (a->ant == b->ant) && (a->stbc == b->stbc) &&
-		(a->bfer == b->bfer);
-
-	if (allow_ant_mismatch) {
-		if (a->stbc || a->bfer) {
-			WARN_ONCE(a->ant != ANT_AB, "stbc %d bfer %d ant %d",
-				  a->stbc, a->bfer, a->ant);
-			ant_match |= (b->ant == ANT_A || b->ant == ANT_B);
-		} else if (b->stbc || b->bfer) {
-			WARN_ONCE(b->ant != ANT_AB, "stbc %d bfer %d ant %d",
-				  b->stbc, b->bfer, b->ant);
-			ant_match |= (a->ant == ANT_A || a->ant == ANT_B);
-		}
-	}
-
-	return (a->type == b->type) && (a->bw == b->bw) && (a->sgi == b->sgi) &&
-		(a->ldpc == b->ldpc) && (a->index == b->index) && ant_match;
-}
-
 /* Check if both rates share the same column */
 static inline bool rs_rate_column_match(struct rs_rate *a,
 					struct rs_rate *b)
@@ -1182,12 +1154,12 @@ void iwl_mvm_rs_tx_status(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 	u32 lq_hwrate;
 	struct rs_rate lq_rate, tx_resp_rate;
 	struct iwl_scale_tbl_info *curr_tbl, *other_tbl, *tmp_tbl;
-	u8 reduced_txp = (uintptr_t)info->status.status_driver_data[0];
+	u32 tlc_info = (uintptr_t)info->status.status_driver_data[0];
+	u8 reduced_txp = tlc_info & RS_DRV_DATA_TXP_MSK;
+	u8 lq_color = RS_DRV_DATA_LQ_COLOR_GET(tlc_info);
 	u32 tx_resp_hwrate = (uintptr_t)info->status.status_driver_data[1];
 	struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);
 	struct iwl_lq_sta *lq_sta = &mvmsta->lq_sta;
-	bool allow_ant_mismatch = fw_has_api(&mvm->fw->ucode_capa,
-					     IWL_UCODE_TLV_API_LQ_SS_PARAMS);
 
 	/* Treat uninitialized rate scaling data same as non-existing. */
 	if (!lq_sta) {
@@ -1262,10 +1234,10 @@ void iwl_mvm_rs_tx_status(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 	rs_rate_from_ucode_rate(lq_hwrate, info->band, &lq_rate);
 
 	/* Here we actually compare this rate to the latest LQ command */
-	if (!rs_rate_equal(&tx_resp_rate, &lq_rate, allow_ant_mismatch)) {
+	if (lq_color != LQ_FLAG_COLOR_GET(table->flags)) {
 		IWL_DEBUG_RATE(mvm,
-			       "initial tx resp rate 0x%x does not match 0x%x\n",
-			       tx_resp_hwrate, lq_hwrate);
+			       "tx resp color 0x%x does not match 0x%x\n",
+			       lq_color, LQ_FLAG_COLOR_GET(table->flags));
 
 		/*
 		 * Since rates mis-match, the last LQ command may have failed.
@@ -3326,6 +3298,7 @@ static void rs_build_rates_table(struct iwl_mvm *mvm,
 	u8 valid_tx_ant = 0;
 	struct iwl_lq_cmd *lq_cmd = &lq_sta->lq;
 	bool toggle_ant = false;
+	u32 color;
 
 	memcpy(&rate, initial_rate, sizeof(rate));
 
@@ -3380,6 +3353,9 @@ static void rs_build_rates_table(struct iwl_mvm *mvm,
 				 num_rates, num_retries, valid_tx_ant,
 				 toggle_ant);
 
+	/* update the color of the LQ command (as a counter at bits 1-3) */
+	color = LQ_FLAGS_COLOR_INC(LQ_FLAG_COLOR_GET(lq_cmd->flags));
+	lq_cmd->flags = LQ_FLAG_COLOR_SET(lq_cmd->flags, color);
 }
 
 struct rs_bfer_active_iter_data {