From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH net-next] net: mscc: allow extracting the FCS into the skb Date: Mon, 1 Oct 2018 09:35:45 -0700 Message-ID: <25a88126-2397-a1fb-0c0d-06504bb348ca@gmail.com> References: <20181001095714.26024-1-antoine.tenart@bootlin.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, alexandre.belloni@bootlin.com, quentin.schulz@bootlin.com, allan.nielsen@microchip.com To: Antoine Tenart , davem@davemloft.net Return-path: In-Reply-To: <20181001095714.26024-1-antoine.tenart@bootlin.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 10/01/2018 02:57 AM, Antoine Tenart 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 > --- > 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; > Don't this needs to be len -= sz; > + if (unlikely(dev->features & NETIF_F_RXFCS)) { > + buf = (u32 *)skb_put(skb, ETH_FCS_LEN); > + *buf = val; and here len -= ETH_FCS_LEN since "len" is later used for accounting how many bytes have been received by the network device? I am bit confused by the use of "buf", but presumably if NETIF_F_RXCFS is turned on, the FCS needs to be part of the buffer passed to the network stack, so adjusting len accordingly is required anyway. -- Florian