Re: [PATCH net-next] net: mscc: allow extracting the FCS into the skb

Alexandre Belloni
2018-10-01T15:00:00Z

On 01/10/2018 11:57:14+0200, Antoine Ténart wrote:
> This patch adds support for the NETIF_F_RXFCS feature in the Mscc
> Ethernet driver. This feature is disabled by default and allow an user
> to request the driver not to drop the FCS and to extract it into the skb
> for debugging purposes.
>
> Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
> drivers/net/ethernet/mscc/ocelot.c | 2 +-
> drivers/net/ethernet/mscc/ocelot_board.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
> index 1a4f2bb48ead..eb5119e7e60b 100644
> --- a/drivers/net/ethernet/mscc/ocelot.c
> +++ b/drivers/net/ethernet/mscc/ocelot.c
> @@ -1606,7 +1606,7 @@ int ocelot_probe_port(struct ocelot *ocelot, u8 port,
> dev->ethtool_ops = &ocelot_ethtool_ops;
> dev->switchdev_ops = &ocelot_port_switchdev_ops;
>
> - dev->hw_features |= NETIF_F_HW_VLAN_CTAG_FILTER;
> + dev->hw_features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_RXFCS;
> dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
>
> memcpy(dev->dev_addr, ocelot->base_mac, ETH_ALEN);
> diff --git a/drivers/net/ethernet/mscc/ocelot_board.c b/drivers/net/ethernet/mscc/ocelot_board.c
> index 3cdf63e35b53..245452a0f244 100644
> --- a/drivers/net/ethernet/mscc/ocelot_board.c
> +++ b/drivers/net/ethernet/mscc/ocelot_board.c
> @@ -126,11 +126,16 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
> len += sz;
> } while (len < buf_len);
>
> - /* Read the FCS and discard it */
> + /* Read the FCS */
> sz = ocelot_rx_frame_word(ocelot, grp, false, &val);
> /* Update the statistics if part of the FCS was read before */
> len -= ETH_FCS_LEN - sz;
>
> + if (unlikely(dev->features & NETIF_F_RXFCS)) {
> + buf = (u32 *)skb_put(skb, ETH_FCS_LEN);
> + *buf = val;
> + }
> +
> if (sz < 0) {
> err = sz;
> break;
> --
> 2.17.1
>

--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering