[Intel-wired-lan] [next PATCH v2 1/4] ixgbe: Add support for generic Tx checksums

[Bowers, AndrewX <andrewx.bowers@intel.com>]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at lists.osuosl.org] On
> Behalf Of Alexander Duyck
> Sent: Wednesday, January 13, 2016 7:31 AM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [next PATCH v2 1/4] ixgbe: Add support for generic
> Tx checksums
> 
> This patch adds support for generic Tx checksums to the ixgbe driver.  It turns
> out this is actually pretty easy after going over the datasheet as we were
> doing a number of steps we didn't need to.
> 
> In order to perform a Tx checksum for an L4 header we need to fill in the
> following fields in the Tx descriptor:
>   MACLEN (maximum of 127), retrieved from:
> 		skb_network_offset()
>   IPLEN  (maximum of 511), retrieved from:
> 		skb_checksum_start_offset() - skb_network_offset()
>   TUCMD.L4T indicates offset and if checksum or crc32c, based on:
> 		skb->csum_offset
> 
> The added advantage to doing this is that we can support inner checksum
> offloads for tunnels and MPLS while still being able to transparently insert
> VLAN tags.
> 
> I also took the opportunity to clean-up many of the feature flag configuration
> bits to make them a bit more consistent between drivers.
> 
> Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  163 +++++++++-------------
> ---
>  1 file changed, 59 insertions(+), 104 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Ethtool shows generic checksum offload support, can be toggled.