From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Wang Subject: Re: [PATCH net-next 2/3] net: dsa: mediatek: combine MediaTek tag with VLAN tag Date: Tue, 12 Dec 2017 15:21:21 +0800 Message-ID: <1513063281.28444.25.camel@mtkswgap22> References: <20171207153016.GC24750@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , , , , , To: Andrew Lunn Return-path: In-Reply-To: <20171207153016.GC24750@lunn.ch> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, 2017-12-07 at 16:30 +0100, Andrew Lunn wrote: > > @@ -25,20 +28,37 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, > > { > > struct dsa_port *dp = dsa_slave_to_port(dev); > > u8 *mtk_tag; > > + bool is_vlan_skb = true; > > .. > > > + /* Mark tag attribute on special tag insertion to notify hardware > > + * whether that's a combined special tag with 802.1Q header. > > + */ > > + mtk_tag[0] = is_vlan_skb ? MTK_HDR_XMIT_TAGGED_TPID_8100 : > > + MTK_HDR_XMIT_UNTAGGED; > > mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK; > > - mtk_tag[2] = 0; > > - mtk_tag[3] = 0; > > + > > + /* Tag control information is kept for 802.1Q */ > > + if (!is_vlan_skb) { > > + mtk_tag[2] = 0; > > + mtk_tag[3] = 0; > > + } > > > > return skb; > > } > > Hi Sean > > So you can mark a packet for egress. What about ingress? How do you > know the VLAN/PORT combination for packets the CPU receives? I would > of expected a similar change to mtk_tag_rcv(). > > Andrew Hi, Andrew It's unnecessary for extra handling in mtk_tag_rcv() when VLAN tag is present since it is able to put the VLAN tag after the special tag and then follow the existing way to parse. Sean