[PATCH 6.18 042/614] wifi: ath12k: fix VHT MCS assignment

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Baochen Qiang <baochen.qiang@oss.qualcomm.com>

[ Upstream commit 8c21b32c2cc82224c7fc1a9f67318f3b1199744b ]

While associating, firmware needs the peer's receive capability
to calculate its own VHT transmit MCS. Currently, the host
sends this information via mcs->rx_mcs_set field, but firmware
actually reads it from mcs->tx_mcs_set field. This mismatch is
incorrect.

This issue has not caused failures so far because most peers
advertise identical TX and RX capabilities. Fix this by
assigning the value to tx_mcs_set as expected.

Additionally, the rate control mask is intended to limit our
transmit MCS, so it should also apply to the peer's receive
capability. Update the logic accordingly.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Signed-off-by: Pradeep Kumar Chitrapu <quic_pradeepc@quicinc.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20251009211656.2386085-2-quic_pradeepc@quicinc.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/ath/ath12k/mac.c |  7 +++----
 drivers/net/wireless/ath/ath12k/wmi.c | 13 ++++++++-----
 drivers/net/wireless/ath/ath12k/wmi.h |  2 ++
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index db351c9220181..4e6d136433202 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -2249,7 +2249,6 @@ static void ath12k_peer_assoc_h_vht(struct ath12k *ar,
 	struct cfg80211_chan_def def;
 	enum nl80211_band band;
 	u16 *vht_mcs_mask;
-	u16 tx_mcs_map;
 	u8 ampdu_factor;
 	u8 max_nss, vht_mcs;
 	int i, vht_nss, nss_idx;
@@ -2340,10 +2339,10 @@ static void ath12k_peer_assoc_h_vht(struct ath12k *ar,
 	arg->peer_nss = min(link_sta->rx_nss, max_nss);
 	arg->rx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.rx_highest);
 	arg->rx_mcs_set = __le16_to_cpu(vht_cap->vht_mcs.rx_mcs_map);
-	arg->tx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.tx_highest);
+	arg->rx_mcs_set = ath12k_peer_assoc_h_vht_limit(arg->rx_mcs_set, vht_mcs_mask);
 
-	tx_mcs_map = __le16_to_cpu(vht_cap->vht_mcs.tx_mcs_map);
-	arg->tx_mcs_set = ath12k_peer_assoc_h_vht_limit(tx_mcs_map, vht_mcs_mask);
+	arg->tx_max_rate = __le16_to_cpu(vht_cap->vht_mcs.tx_highest);
+	arg->tx_mcs_set = __le16_to_cpu(vht_cap->vht_mcs.tx_mcs_map);
 
 	/* In QCN9274 platform, VHT MCS rate 10 and 11 is enabled by default.
 	 * VHT MCS rate 10 and 11 is not supported in 11ac standard.
diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
index ff6b3d4ea8208..e76275bd6916f 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.c
+++ b/drivers/net/wireless/ath/ath12k/wmi.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause-Clear
 /*
  * Copyright (c) 2018-2021 The Linux Foundation. All rights reserved.
- * Copyright (c) 2021-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  */
 #include <linux/skbuff.h>
 #include <linux/ctype.h>
@@ -2367,10 +2367,13 @@ int ath12k_wmi_send_peer_assoc_cmd(struct ath12k *ar,
 	cmd->peer_bw_rxnss_override |= cpu_to_le32(arg->peer_bw_rxnss_override);
 
 	if (arg->vht_capable) {
-		mcs->rx_max_rate = cpu_to_le32(arg->rx_max_rate);
-		mcs->rx_mcs_set = cpu_to_le32(arg->rx_mcs_set);
-		mcs->tx_max_rate = cpu_to_le32(arg->tx_max_rate);
-		mcs->tx_mcs_set = cpu_to_le32(arg->tx_mcs_set);
+		/* Firmware interprets mcs->tx_mcs_set field as peer's
+		 * RX capability
+		 */
+		mcs->rx_max_rate = cpu_to_le32(arg->tx_max_rate);
+		mcs->rx_mcs_set = cpu_to_le32(arg->tx_mcs_set);
+		mcs->tx_max_rate = cpu_to_le32(arg->rx_max_rate);
+		mcs->tx_mcs_set = cpu_to_le32(arg->rx_mcs_set);
 	}
 
 	/* HE Rates */
diff --git a/drivers/net/wireless/ath/ath12k/wmi.h b/drivers/net/wireless/ath/ath12k/wmi.h
index a8c3190e8ad95..6d9c645e3d5d0 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.h
+++ b/drivers/net/wireless/ath/ath12k/wmi.h
@@ -4218,8 +4218,10 @@ struct wmi_unit_test_cmd {
 struct ath12k_wmi_vht_rate_set_params {
 	__le32 tlv_header;
 	__le32 rx_max_rate;
+	/* MCS at which the peer can transmit */
 	__le32 rx_mcs_set;
 	__le32 tx_max_rate;
+	/* MCS at which the peer can receive */
 	__le32 tx_mcs_set;
 	__le32 tx_max_mcs_nss;
 } __packed;
-- 
2.51.0