[PATCH 3/3] wifi: mt76: mt7615: drop TXRX_NOTIFY on non-mmio buses

[Devin Wittmayer]

PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7615_rx_check() and
mt7615_queue_rx_skb() dispatch it to mt7615_mac_tx_free() on every bus.
mt7615_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on the mt7663 USB and SDIO
buses it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX
worker. Same defect as the mt7921 and mt7925 patches in this series.

Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").

Fixes: eb99cc95c3b6 ("mt76: mt7615: introduce mt7663u support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Devin Wittmayer <lucid_duck@xxxxxxxxxxxxx>
---
 drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index ce0051468501..aad232c5a6fa 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -1601,6 +1601,8 @@ bool mt7615_rx_check(struct mt76_dev *mdev, void *data, int len)
 
 	switch (type) {
 	case PKT_TYPE_TXRX_NOTIFY:
+		if (!mt76_is_mmio(mdev))
+			return false;
 		mt7615_mac_tx_free(dev, data, len);
 		return false;
 	case PKT_TYPE_TXS:
@@ -1634,6 +1636,10 @@ void mt7615_queue_rx_skb(struct mt76_dev *mdev, enum mt76_rxq_id q,
 		dev_kfree_skb(skb);
 		break;
 	case PKT_TYPE_TXRX_NOTIFY:
+		if (!mt76_is_mmio(mdev)) {
+			dev_kfree_skb(skb);
+			break;
+		}
 		mt7615_mac_tx_free(dev, skb->data, skb->len);
 		dev_kfree_skb(skb);
 		break;
-- 
2.54.0