wifi: ath12k: fix firmware assert during channel switch for peer sta

Currently, during change in bandwidth for peer sta, host sends the
new value of channel width via WMI_PEER_CHWIDTH set peer param command
alone. This can lead to firmware assert in some scenario since before
the command, firmware was having value of channel width and its
corresponding phymode. After the command, host tries to set the new
value of channel width alone which can become incompatible when compared
with its phymode.

For example:

Bandwidth Upgrade
~~~~~~~~~~~~~~~~~~
After association, sta is in 40 MHz bandwidth in 11ax-HE40 phymode.
After bandwidth upgrades, sta moves to 80 MHz but as per phymode,
max bandwidth is still 40 MHz. Hence, firmware assert is seen.
So in this case first phymode should be moved to 11ax-HE80
followed by bandwidth change.

Bandwidth Downgrade
~~~~~~~~~~~~~~~~~~
Similarly, reverse of above is also possible when sta is in 40 MHz
bandwidth in 11ax-HE40 phymode. Bandwidth should be changed to 20 MHz
and if host sends phymode first then, phymode will become 11ax-HE20
and will be incompatible with bandwidth value and hence firmware
assert will be seen. Hence, in this case first channel width
should be set followed by phymode.

Fix this issue by sending WMI set peer param command for phymode as
well as bandwidth based on the type of bandwidth change i.e upgrade
or downgrade.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Signed-off-by: Aaradhana Sahu <quic_aarasahu@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230315113202.8774-1-quic_aarasahu@quicinc.com

drivers/net/wireless/ath/ath12k/core.h

@@ -395,6 +395,7 @@ struct ath12k_sta {
 	u8 rssi_comb;
 	struct ath12k_rx_peer_stats *rx_stats;
 	struct ath12k_wbm_tx_stats *wbm_tx_stats;
+	u32 bw_prev;
 };
 
 #define ATH12K_MIN_5G_FREQ 4150

drivers/net/wireless/ath/ath12k/mac.c

@@ -3220,10 +3220,11 @@ static void ath12k_sta_rc_update_wk(struct work_struct *wk)
 	enum nl80211_band band;
 	const u8 *ht_mcs_mask;
 	const u16 *vht_mcs_mask;
-	u32 changed, bw, nss, smps;
+	u32 changed, bw, nss, smps, bw_prev;
 	int err, num_vht_rates;
 	const struct cfg80211_bitrate_mask *mask;
 	struct ath12k_wmi_peer_assoc_arg peer_arg;
+	enum wmi_phy_mode peer_phymode;
 
 	arsta = container_of(wk, struct ath12k_sta, update_wk);
 	sta = container_of((void *)arsta, struct ieee80211_sta, drv_priv);
@@ -3243,6 +3244,7 @@ static void ath12k_sta_rc_update_wk(struct work_struct *wk)
 	arsta->changed = 0;
 
 	bw = arsta->bw;
+	bw_prev = arsta->bw_prev;
 	nss = arsta->nss;
 	smps = arsta->smps;
 
@@ -3255,11 +3257,53 @@ static void ath12k_sta_rc_update_wk(struct work_struct *wk)
 			   ath12k_mac_max_vht_nss(vht_mcs_mask)));
 
 	if (changed & IEEE80211_RC_BW_CHANGED) {
-		err = ath12k_wmi_set_peer_param(ar, sta->addr, arvif->vdev_id,
-						WMI_PEER_CHWIDTH, bw);
-		if (err)
-			ath12k_warn(ar->ab, "failed to update STA %pM peer bw %d: %d\n",
-				    sta->addr, bw, err);
+		ath12k_peer_assoc_h_phymode(ar, arvif->vif, sta, &peer_arg);
+		peer_phymode = peer_arg.peer_phymode;
+
+		if (bw > bw_prev) {
+			/* Phymode shows maximum supported channel width, if we
+			 * upgrade bandwidth then due to sanity check of firmware,
+			 * we have to send WMI_PEER_PHYMODE followed by
+			 * WMI_PEER_CHWIDTH
+			 */
+			ath12k_dbg(ar->ab, ATH12K_DBG_MAC, "mac bandwidth upgrade for sta %pM new %d old %d\n",
+				   sta->addr, bw, bw_prev);
+			err = ath12k_wmi_set_peer_param(ar, sta->addr,
+							arvif->vdev_id, WMI_PEER_PHYMODE,
+							peer_phymode);
+			if (err) {
+				ath12k_warn(ar->ab, "failed to update STA %pM to peer phymode %d: %d\n",
+					    sta->addr, peer_phymode, err);
+				goto err_rc_bw_changed;
+			}
+			err = ath12k_wmi_set_peer_param(ar, sta->addr,
+							arvif->vdev_id, WMI_PEER_CHWIDTH,
+							bw);
+			if (err)
+				ath12k_warn(ar->ab, "failed to update STA %pM to peer bandwidth %d: %d\n",
+					    sta->addr, bw, err);
+		} else {
+			/* When we downgrade bandwidth this will conflict with phymode
+			 * and cause to trigger firmware crash. In this case we send
+			 * WMI_PEER_CHWIDTH followed by WMI_PEER_PHYMODE
+			 */
+			ath12k_dbg(ar->ab, ATH12K_DBG_MAC, "mac bandwidth downgrade for sta %pM new %d old %d\n",
+				   sta->addr, bw, bw_prev);
+			err = ath12k_wmi_set_peer_param(ar, sta->addr,
+							arvif->vdev_id, WMI_PEER_CHWIDTH,
+							bw);
+			if (err) {
+				ath12k_warn(ar->ab, "failed to update STA %pM peer to bandwidth %d: %d\n",
+					    sta->addr, bw, err);
+				goto err_rc_bw_changed;
+			}
+			err = ath12k_wmi_set_peer_param(ar, sta->addr,
+							arvif->vdev_id, WMI_PEER_PHYMODE,
+							peer_phymode);
+			if (err)
+				ath12k_warn(ar->ab, "failed to update STA %pM to peer phymode %d: %d\n",
+					    sta->addr, peer_phymode, err);
+		}
 	}
 
 	if (changed & IEEE80211_RC_NSS_CHANGED) {
@@ -3321,7 +3365,7 @@ static void ath12k_sta_rc_update_wk(struct work_struct *wk)
 					    sta->addr, arvif->vdev_id);
 		}
 	}
-
+err_rc_bw_changed:
 	mutex_unlock(&ar->conf_mutex);
 }
 
@@ -3433,6 +3477,34 @@ static int ath12k_mac_station_add(struct ath12k *ar,
 	return ret;
 }
 
+static u32 ath12k_mac_ieee80211_sta_bw_to_wmi(struct ath12k *ar,
+					      struct ieee80211_sta *sta)
+{
+	u32 bw = WMI_PEER_CHWIDTH_20MHZ;
+
+	switch (sta->deflink.bandwidth) {
+	case IEEE80211_STA_RX_BW_20:
+		bw = WMI_PEER_CHWIDTH_20MHZ;
+		break;
+	case IEEE80211_STA_RX_BW_40:
+		bw = WMI_PEER_CHWIDTH_40MHZ;
+		break;
+	case IEEE80211_STA_RX_BW_80:
+		bw = WMI_PEER_CHWIDTH_80MHZ;
+		break;
+	case IEEE80211_STA_RX_BW_160:
+		bw = WMI_PEER_CHWIDTH_160MHZ;
+		break;
+	default:
+		ath12k_warn(ar->ab, "Invalid bandwidth %d in rc update for %pM\n",
+			    sta->deflink.bandwidth, sta->addr);
+		bw = WMI_PEER_CHWIDTH_20MHZ;
+		break;
+	}
+
+	return bw;
+}
+
 static int ath12k_mac_op_sta_state(struct ieee80211_hw *hw,
 				   struct ieee80211_vif *vif,
 				   struct ieee80211_sta *sta,
@@ -3498,6 +3570,13 @@ static int ath12k_mac_op_sta_state(struct ieee80211_hw *hw,
 		if (ret)
 			ath12k_warn(ar->ab, "Failed to associate station: %pM\n",
 				    sta->addr);
+
+		spin_lock_bh(&ar->data_lock);
+
+		arsta->bw = ath12k_mac_ieee80211_sta_bw_to_wmi(ar, sta);
+		arsta->bw_prev = sta->deflink.bandwidth;
+
+		spin_unlock_bh(&ar->data_lock);
 	} else if (old_state == IEEE80211_STA_ASSOC &&
 		   new_state == IEEE80211_STA_AUTHORIZED) {
 		spin_lock_bh(&ar->ab->base_lock);
@@ -3607,28 +3686,8 @@ static void ath12k_mac_op_sta_rc_update(struct ieee80211_hw *hw,
 	spin_lock_bh(&ar->data_lock);
 
 	if (changed & IEEE80211_RC_BW_CHANGED) {
-		bw = WMI_PEER_CHWIDTH_20MHZ;
-
-		switch (sta->deflink.bandwidth) {
-		case IEEE80211_STA_RX_BW_20:
-			bw = WMI_PEER_CHWIDTH_20MHZ;
-			break;
-		case IEEE80211_STA_RX_BW_40:
-			bw = WMI_PEER_CHWIDTH_40MHZ;
-			break;
-		case IEEE80211_STA_RX_BW_80:
-			bw = WMI_PEER_CHWIDTH_80MHZ;
-			break;
-		case IEEE80211_STA_RX_BW_160:
-			bw = WMI_PEER_CHWIDTH_160MHZ;
-			break;
-		default:
-			ath12k_warn(ar->ab, "Invalid bandwidth %d in rc update for %pM\n",
-				    sta->deflink.bandwidth, sta->addr);
-			bw = WMI_PEER_CHWIDTH_20MHZ;
-			break;
-		}
-
+		bw = ath12k_mac_ieee80211_sta_bw_to_wmi(ar, sta);
+		arsta->bw_prev = arsta->bw;
 		arsta->bw = bw;
 	}