| /* |
| * Mediatek DSA Tag support |
| * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com> |
| * Sean Wang <sean.wang@mediatek.com> |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 and |
| * only version 2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/etherdevice.h> |
| |
| #include "dsa_priv.h" |
| |
| #define MTK_HDR_LEN 4 |
| #define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0) |
| #define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0) |
| |
| static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, |
| struct net_device *dev) |
| { |
| struct dsa_port *dp = dsa_slave_to_port(dev); |
| u8 *mtk_tag; |
| |
| if (skb_cow_head(skb, MTK_HDR_LEN) < 0) |
| return NULL; |
| |
| skb_push(skb, MTK_HDR_LEN); |
| |
| memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN); |
| |
| /* Build the tag after the MAC Source Address */ |
| mtk_tag = skb->data + 2 * ETH_ALEN; |
| mtk_tag[0] = 0; |
| mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK; |
| mtk_tag[2] = 0; |
| mtk_tag[3] = 0; |
| |
| return skb; |
| } |
| |
| static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev, |
| struct packet_type *pt) |
| { |
| int port; |
| __be16 *phdr, hdr; |
| |
| if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN))) |
| return NULL; |
| |
| /* The MTK header is added by the switch between src addr |
| * and ethertype at this point, skb->data points to 2 bytes |
| * after src addr so header should be 2 bytes right before. |
| */ |
| phdr = (__be16 *)(skb->data - 2); |
| hdr = ntohs(*phdr); |
| |
| /* Remove MTK tag and recalculate checksum. */ |
| skb_pull_rcsum(skb, MTK_HDR_LEN); |
| |
| memmove(skb->data - ETH_HLEN, |
| skb->data - ETH_HLEN - MTK_HDR_LEN, |
| 2 * ETH_ALEN); |
| |
| /* Get source port information */ |
| port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK); |
| |
| skb->dev = dsa_master_find_slave(dev, 0, port); |
| if (!skb->dev) |
| return NULL; |
| |
| return skb; |
| } |
| |
| static int mtk_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto, |
| int *offset) |
| { |
| *offset = 4; |
| *proto = ((__be16 *)skb->data)[1]; |
| |
| return 0; |
| } |
| |
| const struct dsa_device_ops mtk_netdev_ops = { |
| .xmit = mtk_tag_xmit, |
| .rcv = mtk_tag_rcv, |
| .flow_dissect = mtk_tag_flow_dissect, |
| }; |