net: airoha: Update tx cpu dma ring idx at the end of xmit loop

Move the tx cpu dma ring index update out of transmit loop of
airoha_dev_xmit routine in order to not start transmitting the packet
before it is fully DMA mapped (e.g. fragmented skbs).

Fixes: 23020f049327 ("net: airoha: Introduce ethernet support for EN7581 SoC")
Reported-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241004-airoha-eth-7581-mapping-fix-v1-1-8e4279ab1812@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mediatek/airoha_eth.c b/drivers/net/ethernet/mediatek/airoha_eth.c
index 930f180..2c26eb1 100644 (file)
--- a/drivers/net/ethernet/mediatek/airoha_eth.c
+++ b/drivers/net/ethernet/mediatek/airoha_eth.c
@@ -2471,10 +2471,6 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
                e->dma_addr = addr;
                e->dma_len = len;
 
-               airoha_qdma_rmw(qdma, REG_TX_CPU_IDX(qid),
-                               TX_RING_CPU_IDX_MASK,
-                               FIELD_PREP(TX_RING_CPU_IDX_MASK, index));
-
                data = skb_frag_address(frag);
                len = skb_frag_size(frag);
        }
@@ -2483,6 +2479,11 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
        q->queued += i;
 
        skb_tx_timestamp(skb);
+       if (!netdev_xmit_more())
+               airoha_qdma_rmw(qdma, REG_TX_CPU_IDX(qid),
+                               TX_RING_CPU_IDX_MASK,
+                               FIELD_PREP(TX_RING_CPU_IDX_MASK, q->head));
+
        if (q->ndesc - q->queued < q->free_thr)
                netif_tx_stop_queue(txq);