diff --git a/target/linux/bmips/files/drivers/net/ethernet/broadcom/bcm6368-enetsw.c b/target/linux/bmips/files/drivers/net/ethernet/broadcom/bcm6368-enetsw.c index 321e95dbbb3..b72a788378f 100644 --- a/target/linux/bmips/files/drivers/net/ethernet/broadcom/bcm6368-enetsw.c +++ b/target/linux/bmips/files/drivers/net/ethernet/broadcom/bcm6368-enetsw.c @@ -22,10 +22,19 @@ #include #include -/* MTU */ -#define ENETSW_TAG_SIZE (6 + VLAN_HLEN) -#define ENETSW_MTU_OVERHEAD (VLAN_ETH_HLEN + VLAN_HLEN + \ - ENETSW_TAG_SIZE) +/* TODO: Bigger frames may work but we do not trust that they are safe on all + * platforms so more research is needed, a max frame size of 2048 has been + * tested. We use the safe frame size 1542 which is 1532 plus DSA and VLAN + * overhead. + */ +#define ENETSW_MAX_FRAME 1542 +#define ENETSW_DSA_TAG_SIZE 6 +/* The MTU in Linux does not include ethernet or VLAN headers, but it DOES + * include the DSA overhead (the framework will increase the MTU to fit + * any DSA header). + */ +#define ENETSW_MAX_MTU (ENETSW_MAX_FRAME - VLAN_ETH_HLEN - \ + VLAN_HLEN) #define ENETSW_FRAG_SIZE(x) (SKB_DATA_ALIGN(NET_SKB_PAD + x + \ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))) @@ -1006,7 +1015,7 @@ static int bcm6368_enetsw_probe(struct platform_device *pdev) dev_info(dev, "random mac\n"); } - priv->rx_buf_size = ALIGN(ndev->mtu + ENETSW_MTU_OVERHEAD, + priv->rx_buf_size = ALIGN(ENETSW_MAX_FRAME, ENETSW_DMA_MAXBURST * 4); priv->rx_frag_size = ENETSW_FRAG_SIZE(priv->rx_buf_size); @@ -1066,8 +1075,8 @@ static int bcm6368_enetsw_probe(struct platform_device *pdev) /* register netdevice */ ndev->netdev_ops = &bcm6368_enetsw_ops; ndev->min_mtu = ETH_ZLEN; - ndev->mtu = ETH_DATA_LEN + ENETSW_TAG_SIZE; - ndev->max_mtu = ETH_DATA_LEN + ENETSW_TAG_SIZE; + ndev->mtu = ETH_DATA_LEN; + ndev->max_mtu = ENETSW_MAX_MTU; #if LINUX_VERSION_CODE >= KERNEL_VERSION(6,1,0) netif_napi_add(ndev, &priv->napi, bcm6368_enetsw_poll); #else