[PATCH 07/23] wifi: mt76: mt7925: add per-peer RX IGTK/BIGTK and RX GTK WTBLs

[Sean Wang]

From: Chengwei Yu <chengwei.yu at mediatek.com>

NAN RX group keys are per-peer: each NAN peer can carry an independent
IGTK/BIGTK, and each NAN_DATA peer an independent GTK. Add
nan_rx_igtk_wcid and nan_rx_gtk_wcid to mt792x_sta to hold dedicated
WTBL entries for these keys.

WTBLs are allocated lazily: mt7925_nan_sta_wcids_init() marks both
fields MT792x_WCID_IDX_UNSET at peer-add time, and
mt7925_nan_peer_wcids_free() releases whichever slots were actually
allocated at peer-remove time. Peers that never install a NAN group
key carry zero overhead.

Co-developed-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Chengwei Yu <chengwei.yu at mediatek.com>
---
 .../net/wireless/mediatek/mt76/mt7925/main.c  | 47 +++++++++++++++++++
 drivers/net/wireless/mediatek/mt76/mt792x.h   | 11 +++++
 2 files changed, 58 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index 3e1c223e8da6..2d3bf7d806a7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -923,6 +923,8 @@ mt7925_get_rates_table(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	return mvif->basic_rates_idx;
 }
 
+static void mt7925_nan_sta_wcids_init(struct mt792x_sta *msta);
+
 static int mt7925_mac_link_sta_add(struct mt76_dev *mdev,
 				   struct ieee80211_vif *vif,
 				   struct ieee80211_link_sta *link_sta,
@@ -1060,6 +1062,9 @@ static int mt7925_mac_link_sta_add(struct mt76_dev *mdev,
 			goto out_pm;
 	}
 
+	if (vif->type == NL80211_IFTYPE_NAN || vif->type == NL80211_IFTYPE_NAN_DATA)
+		mt7925_nan_sta_wcids_init(msta);
+
 	mt76_connac_power_save_sched(&dev->mphy, &dev->pm);
 
 	return 0;
@@ -1306,6 +1311,45 @@ int mt7925_mac_sta_event(struct mt76_dev *mdev, struct ieee80211_vif *vif,
 }
 EXPORT_SYMBOL_GPL(mt7925_mac_sta_event);
 
+/* Mark per-peer NAN group key WTBLs as unallocated at station add time.
+ * Pairs with mt7925_nan_peer_wcids_free() at station remove time.
+ */
+static void mt7925_nan_sta_wcids_init(struct mt792x_sta *msta)
+{
+	msta->nan_rx_gtk_wcid.idx = MT792x_WCID_IDX_UNSET;
+	msta->nan_rx_igtk_wcid.idx = MT792x_WCID_IDX_UNSET;
+}
+
+/* Free a lazily-allocated per-peer NAN group key WTBL and reset its sentinel. */
+static void mt7925_nan_wcid_free(struct mt76_dev *mdev, struct mt76_wcid *wcid)
+{
+	u16 idx = wcid->idx;
+
+	rcu_assign_pointer(mdev->wcid[idx], NULL);
+	mt76_wcid_cleanup(mdev, wcid);
+	mt76_wcid_mask_clear(mdev->wcid_mask, idx);
+	wcid->idx = MT792x_WCID_IDX_UNSET;
+}
+
+/* Release any lazily-allocated per-peer NAN group key WTBLs for a departing
+ * station.  Called from mt7925_mac_link_sta_remove() after the primary WTBL
+ * is already freed, so the NAN-specific cleanup is clearly separated from the
+ * generic STA teardown path.
+ */
+static void mt7925_nan_peer_wcids_free(struct mt76_dev *mdev,
+				       struct ieee80211_vif *vif,
+				       struct ieee80211_sta *sta)
+{
+	struct mt792x_sta *msta = (struct mt792x_sta *)sta->drv_priv;
+
+	if (vif->type == NL80211_IFTYPE_NAN_DATA &&
+	    msta->nan_rx_gtk_wcid.idx != MT792x_WCID_IDX_UNSET)
+		mt7925_nan_wcid_free(mdev, &msta->nan_rx_gtk_wcid);
+
+	if (msta->nan_rx_igtk_wcid.idx != MT792x_WCID_IDX_UNSET)
+		mt7925_nan_wcid_free(mdev, &msta->nan_rx_igtk_wcid);
+}
+
 static void mt7925_mac_link_sta_remove(struct mt76_dev *mdev,
 				       struct ieee80211_vif *vif,
 				       struct ieee80211_link_sta *link_sta,
@@ -1350,6 +1394,9 @@ static void mt7925_mac_link_sta_remove(struct mt76_dev *mdev,
 	mt76_wcid_cleanup(mdev, wcid);
 	mt76_wcid_mask_clear(mdev->wcid_mask, idx);
 
+	if (vif->type == NL80211_IFTYPE_NAN || vif->type == NL80211_IFTYPE_NAN_DATA)
+		mt7925_nan_peer_wcids_free(mdev, vif, link_sta->sta);
+
 	mt76_connac_power_save_sched(&dev->mphy, &dev->pm);
 }
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x.h b/drivers/net/wireless/mediatek/mt76/mt792x.h
index fa28a77d12bb..707ca24193f9 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x.h
+++ b/drivers/net/wireless/mediatek/mt76/mt792x.h
@@ -18,6 +18,11 @@
 #define MT792x_WTBL_SIZE	20
 #define MT792x_WTBL_RESERVED	(MT792x_WTBL_SIZE - 1)
 #define MT792x_WTBL_STA		(MT792x_WTBL_RESERVED - MT792x_MAX_INTERFACES)
+/* Sentinel for a lazily-allocated wcid that has not yet been assigned a slot.
+ * U16_MAX is outside every valid alloc range and matches the 0xffff value
+ * used in mt76 DMA ring entries to mark an unused wcid field.
+ */
+#define MT792x_WCID_IDX_UNSET	U16_MAX
 
 #define MT792x_CFEND_RATE_DEFAULT	0x49	/* OFDM 24M */
 #define MT792x_CFEND_RATE_11B		0x03	/* 11B LP, 11M */
@@ -148,6 +153,12 @@ struct mt792x_sta {
 
 	/* NAN peer schedule */
 	struct mt792x_sta_nan_sched nan_sched;
+
+	/* NAN per-peer group key WTBLs (allocated lazily when keys are installed)
+	 * Note: TX GTK is interface-level, see mt792x_vif->nan_tx_gtk_table
+	 */
+	struct mt76_wcid nan_rx_gtk_wcid;    /* NAN_DATA peer: RX GTK WTBL (per-peer) */
+	struct mt76_wcid nan_rx_igtk_wcid;   /* NAN peer: RX IGTK/BIGTK WTBL (per-peer) */
 };
 
 DECLARE_EWMA(rssi, 10, 8);
-- 
2.43.0