mt76: dma: introduce skb field in mt76_txwi_cache

Introduce skb field in mt76_txwi_cache. Moreover add txwi_flags
to mt76_driver_ops since new chipsets will release mt76_txwi_cache/skbs
at tx completion instead of dma one.
This is a preliminary patch to add mt7615 support

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -174,6 +174,7 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 			dev->drv->tx_complete_skb(dev, qid, &entry);
 
 		if (entry.txwi) {
+			if (!(dev->drv->txwi_flags & MT_TXWI_NO_FREE))
 				mt76_put_txwi(dev, entry.txwi);
 			wake = !flush;
 		}

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

@@ -232,6 +232,8 @@ struct mt76_txq {
 struct mt76_txwi_cache {
 	struct list_head list;
 	dma_addr_t dma_addr;
+
+	struct sk_buff *skb;
 };
 
 struct mt76_rx_tid {
@@ -285,8 +287,11 @@ struct mt76_hw_cap {
 	bool has_5ghz;
 };
 
+#define MT_TXWI_NO_FREE			BIT(0)
+
 struct mt76_driver_ops {
 	bool tx_aligned4_skbs;
+	u32 txwi_flags;
 	u16 txwi_size;
 
 	void (*update_survey)(struct mt76_dev *dev);

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

@@ -74,6 +74,7 @@ mt76_put_txwi(struct mt76_dev *dev, struct mt76_txwi_cache *t)
 	list_add(&t->list, &dev->txwi_cache);
 	spin_unlock_bh(&dev->lock);
 }
+EXPORT_SYMBOL_GPL(mt76_put_txwi);
 
 void mt76_tx_free(struct mt76_dev *dev)
 {