iwlwifi: mvm: set max amsdu for TLC offload

mac80211 sets max amsdu to min supported ht vs vht but TLC only works
with one mode so we can set to the exact mode used (vht/ht)
and enable larger amsdu sizes for vht.
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -6,7 +6,7 @@
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2017        Intel Deutschland GmbH
- * Copyright(c) 2018 Intel Corporation
+ * Copyright(c) 2018 - 2019 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
@@ -27,7 +27,7 @@
  * BSD LICENSE
  *
  * Copyright(c) 2017        Intel Deutschland GmbH
- * Copyright(c) 2018 Intel Corporation
+ * Copyright(c) 2018 - 2019 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -345,6 +345,37 @@ void iwl_mvm_tlc_update_notif(struct iwl_mvm *mvm,
 	rcu_read_unlock();
 }
 
+static u16 rs_fw_get_max_amsdu_len(struct ieee80211_sta *sta)
+{
+	const struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
+	const struct ieee80211_sta_ht_cap *ht_cap = &sta->ht_cap;
+
+	if (vht_cap && vht_cap->vht_supported) {
+		switch (vht_cap->cap & IEEE80211_VHT_CAP_MAX_MPDU_MASK) {
+		case IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454:
+			return IEEE80211_MAX_MPDU_LEN_VHT_11454;
+		case IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_7991:
+			return IEEE80211_MAX_MPDU_LEN_VHT_7991;
+		default:
+			return IEEE80211_MAX_MPDU_LEN_VHT_3895;
+	}
+
+	} else if (ht_cap && ht_cap->ht_supported) {
+		if (ht_cap->cap & IEEE80211_HT_CAP_MAX_AMSDU)
+			/*
+			 * agg is offloaded so we need to assume that agg
+			 * are enabled and max mpdu in ampdu is 4095
+			 * (spec 802.11-2016 9.3.2.1)
+			 */
+			return IEEE80211_MAX_MPDU_LEN_HT_BA;
+		else
+			return IEEE80211_MAX_MPDU_LEN_HT_3839;
+	}
+
+	/* in legacy mode no amsdu is enabled so return zero */
+	return 0;
+}
+
 void rs_fw_rate_init(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 		     enum nl80211_band band, bool update)
 {
@@ -353,14 +384,15 @@ void rs_fw_rate_init(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 	struct iwl_lq_sta_rs_fw *lq_sta = &mvmsta->lq_sta.rs_fw;
 	u32 cmd_id = iwl_cmd_id(TLC_MNG_CONFIG_CMD, DATA_PATH_GROUP, 0);
 	struct ieee80211_supported_band *sband;
+	u16 max_amsdu_len = rs_fw_get_max_amsdu_len(sta);
 	struct iwl_tlc_config_cmd cfg_cmd = {
 		.sta_id = mvmsta->sta_id,
 		.max_ch_width = update ?
 			rs_fw_bw_from_sta_bw(sta) : RATE_MCS_CHAN_WIDTH_20,
 		.flags = cpu_to_le16(rs_fw_set_config_flags(mvm, sta)),
 		.chains = rs_fw_set_active_chains(iwl_mvm_get_valid_tx_ant(mvm)),
-		.max_mpdu_len = cpu_to_le16(sta->max_amsdu_len),
 		.sgi_ch_width_supp = rs_fw_sgi_cw_support(sta),
+		.max_mpdu_len = cpu_to_le16(max_amsdu_len),
 		.amsdu = iwl_mvm_is_csum_supported(mvm),
 	};
 	int ret;
@@ -373,6 +405,12 @@ void rs_fw_rate_init(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
 	sband = hw->wiphy->bands[band];
 	rs_fw_set_supp_rates(sta, sband, &cfg_cmd);
 
+	/*
+	 * since TLC offload works with one mode we can assume
+	 * that only vht/ht is used and also set it as station max amsdu
+	 */
+	sta->max_amsdu_len = max_amsdu_len;
+
 	ret = iwl_mvm_send_cmd_pdu(mvm, cmd_id, 0, sizeof(cfg_cmd), &cfg_cmd);
 	if (ret)
 		IWL_ERR(mvm, "Failed to send rate scale config (%d)\n", ret);