Re: [RFC 07/12] ravb: Fillup ravb_rx_gbeth() stub

On 10/6/21 11:22 PM, Biju Das wrote:

[...]

quoted

quoted

Fillup ravb_rx_gbeth() function to support RZ/G2L.

This patch also renames ravb_rcar_rx to ravb_rx_rcar to be consistent
with the naming convention used in sh_eth driver.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar
[off-list ref][...]

diff --git a/drivers/net/ethernet/renesas/ravb_main.c

b/drivers/net/ethernet/renesas/ravb_main.c
index 37164a983156..42573eac82b9 100644

--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c

@@ -720,6 +720,23 @@ static void ravb_get_tx_tstamp(struct net_device

*ndev)

quoted

 	}
 }

+static void ravb_rx_csum_gbeth(struct sk_buff *skb) {
+	u8 *hw_csum;
+
+	/* The hardware checksum is contained in sizeof(__sum16) (2) bytes
+	 * appended to packet data
+	 */
+	if (unlikely(skb->len < sizeof(__sum16)))
+		return;
+	hw_csum = skb_tail_pointer(skb) - sizeof(__sum16);

   Not 32-bit? The manual says the IP checksum is stored in the first 2
bytes.

It is 16 bit. It is on last 2 bytes.

   So you're saying the manual is wrong?

quoted

quoted

+
+	if (*hw_csum == 0)

   You only check the 1st byte, not the full checksum!

As I said earlier, "0" value on last 16 bit, means no checksum error.

   How's that? 'hw_csum' is declaread as 'u8 *'!

quoted

quoted

+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+	else
+		skb->ip_summed = CHECKSUM_NONE;

  So the TCP/UDP/ICMP checksums are not dealt with? Why enable them then?

If last 2bytes is zero, means there is no checksum error w.r.to TCP/UDP/ICMP checksums.

   Why checksum them independently then?

RZ/G2L checksum part is different from R-Car Gen3. There is no TOE block at all for R-Car Gen3.

Regards,
Biju

[...]

MBR, Sergey