From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: [PATCH 3/3] net: fec: align IP header in hardware Date: Mon, 26 Sep 2016 09:26:33 +0000 Message-ID: <063D6719AE5E284EB5DD2968C1650D6DB0109865@AcuExch.aculab.com> References: <1474728139-9335-1-git-send-email-eric@nelint.com> <1474728139-9335-4-git-send-email-eric@nelint.com> Mime-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 8BIT Cc: "linux@arm.linux.org.uk" , "andrew@lunn.ch" , "fugang.duan@nxp.com" , "otavio@ossystems.com.br" , "edumazet@google.com" , "troy.kisky@boundarydevices.com" , "davem@davemloft.net" , "u.kleine-koenig@pengutronix.de" To: 'Eric Nelson' , "netdev@vger.kernel.org" Return-path: Received: from smtp-out6.electric.net ([192.162.217.186]:50200 "EHLO smtp-out6.electric.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761370AbcIZJ3g (ORCPT ); Mon, 26 Sep 2016 05:29:36 -0400 In-Reply-To: <1474728139-9335-4-git-send-email-eric@nelint.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Nelson > Sent: 24 September 2016 15:42 > The FEC receive accelerator (RACC) supports shifting the data payload of > received packets by 16-bits, which aligns the payload (IP header) on a > 4-byte boundary, which is, if not required, at least strongly suggested > by the Linux networking layer. ... > + /* align IP header */ > + val |= FEC_RACC_SHIFT16; I can't help feeling that there needs to be corresponding changes to increase the buffer size by 2 (maybe for large mtu) and to discard two bytes from the frame length. If probably ought to be predicated on NET_IP_ALIGN as well. David