mt76: mt76x02: improve tx hang detection

Instead of checking if any queue has not made progress since the last run,
only trigger hang detection if one of the queues has not made any progress
in 10 subsequent runs. This should reduce false positive firmware restarts
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x02.h

@@ -103,7 +103,7 @@ struct mt76x02_dev {
 	u8 tbtt_count;
 
 	u32 tx_hang_reset;
-	u8 tx_hang_check;
+	u8 tx_hang_check[4];
 	u8 beacon_hang_check;
 	u8 mcu_timeout;
 

drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c

@@ -348,18 +348,20 @@ static bool mt76x02_tx_hang(struct mt76x02_dev *dev)
 	for (i = 0; i < 4; i++) {
 		q = dev->mphy.q_tx[i];
 
-		if (!q->queued)
-			continue;
-
 		prev_dma_idx = dev->mt76.tx_dma_idx[i];
 		dma_idx = readl(&q->regs->dma_idx);
 		dev->mt76.tx_dma_idx[i] = dma_idx;
 
-		if (prev_dma_idx == dma_idx)
-			break;
+		if (!q->queued || prev_dma_idx != dma_idx) {
+			dev->tx_hang_check[i] = 0;
+			continue;
+		}
+
+		if (++dev->tx_hang_check[i] >= MT_TX_HANG_TH)
+			return true;
 	}
 
-	return i < 4;
+	return false;
 }
 
 static void mt76x02_key_sync(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
@@ -530,23 +532,13 @@ static void mt76x02_check_tx_hang(struct mt76x02_dev *dev)
 	if (test_bit(MT76_RESTART, &dev->mphy.state))
 		return;
 
-	if (mt76x02_tx_hang(dev)) {
-		if (++dev->tx_hang_check >= MT_TX_HANG_TH)
-			goto restart;
-	} else {
-		dev->tx_hang_check = 0;
-	}
-
-	if (dev->mcu_timeout)
-		goto restart;
-
-	return;
+	if (!mt76x02_tx_hang(dev) && !dev->mcu_timeout)
+		return;
 
-restart:
 	mt76x02_watchdog_reset(dev);
 
 	dev->tx_hang_reset++;
-	dev->tx_hang_check = 0;
+	memset(dev->tx_hang_check, 0, sizeof(dev->tx_hang_check));
 	memset(dev->mt76.tx_dma_idx, 0xff,
 	       sizeof(dev->mt76.tx_dma_idx));
 }