iwlwifi: rs: set RTS protection for all non legacy rates

This helps with congested environments reducing the conflict cost to
RTS retries only, instead of the entire BA packet.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200928121852.da97d87d7adf.If06301d4660b14e459195a15831b069b9f6c5e3c@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/fw/api/rs.h

@@ -7,7 +7,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2018 - 2019 Intel Corporation
+ * Copyright(c) 2018 - 2020 Intel Corporation
  *
  * 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
@@ -29,7 +29,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2018 - 2019 Intel Corporation
+ * Copyright(c) 2018 - 2020 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -486,6 +486,13 @@ enum {
 #define RATE_MCS_HE_106T_POS		28
 #define RATE_MCS_HE_106T_MSK		(1 << RATE_MCS_HE_106T_POS)
 
+/* Bit 30-31: (1) RTS, (2) CTS */
+#define RATE_MCS_RTS_REQUIRED_POS  (30)
+#define RATE_MCS_RTS_REQUIRED_MSK  (0x1 << RATE_MCS_RTS_REQUIRED_POS)
+
+#define RATE_MCS_CTS_REQUIRED_POS  (31)
+#define RATE_MCS_CTS_REQUIRED_MSK  (0x1 << RATE_MCS_CTS_REQUIRED_POS)
+
 /* Link Quality definitions */
 
 /* # entries in rate scale table to support Tx retries */

drivers/net/wireless/intel/iwlwifi/mvm/rs.c

@@ -830,6 +830,12 @@ static u32 ucode_rate_from_rs_rate(struct iwl_mvm *mvm,
 		return ucode_rate;
 	}
 
+	/* set RTS protection for all non legacy rates
+	 * This helps with congested environments reducing the conflict cost to
+	 * RTS retries only, instead of the entire BA packet.
+	 */
+	ucode_rate |= RATE_MCS_RTS_REQUIRED_MSK;
+
 	if (is_ht(rate)) {
 		if (index < IWL_FIRST_HT_RATE || index > IWL_LAST_HT_RATE) {
 			IWL_ERR(mvm, "Invalid HT rate index %d\n", index);