1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Mediatek DSA Tag support 4 * Copyright (C) 2017 Landen Chao <landen.chao@mediatek.com> 5 * Sean Wang <sean.wang@mediatek.com> 6 */ 7 8 #include <linux/etherdevice.h> 9 #include <linux/if_vlan.h> 10 11 #include "dsa_priv.h" 12 13 #define MTK_HDR_LEN 4 14 #define MTK_HDR_XMIT_UNTAGGED 0 15 #define MTK_HDR_XMIT_TAGGED_TPID_8100 1 16 #define MTK_HDR_XMIT_TAGGED_TPID_88A8 2 17 #define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0) 18 #define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0) 19 #define MTK_HDR_XMIT_SA_DIS BIT(6) 20 21 static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, 22 struct net_device *dev) 23 { 24 struct dsa_port *dp = dsa_slave_to_port(dev); 25 u8 xmit_tpid; 26 u8 *mtk_tag; 27 28 /* Build the special tag after the MAC Source Address. If VLAN header 29 * is present, it's required that VLAN header and special tag is 30 * being combined. Only in this way we can allow the switch can parse 31 * the both special and VLAN tag at the same time and then look up VLAN 32 * table with VID. 33 */ 34 switch (skb->protocol) { 35 case htons(ETH_P_8021Q): 36 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100; 37 break; 38 case htons(ETH_P_8021AD): 39 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8; 40 break; 41 default: 42 xmit_tpid = MTK_HDR_XMIT_UNTAGGED; 43 skb_push(skb, MTK_HDR_LEN); 44 dsa_alloc_etype_header(skb, MTK_HDR_LEN); 45 } 46 47 mtk_tag = dsa_etype_header_pos_tx(skb); 48 49 /* Mark tag attribute on special tag insertion to notify hardware 50 * whether that's a combined special tag with 802.1Q header. 51 */ 52 mtk_tag[0] = xmit_tpid; 53 mtk_tag[1] = (1 << dp->index) & MTK_HDR_XMIT_DP_BIT_MASK; 54 55 /* Tag control information is kept for 802.1Q */ 56 if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) { 57 mtk_tag[2] = 0; 58 mtk_tag[3] = 0; 59 } 60 61 return skb; 62 } 63 64 static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev) 65 { 66 u16 hdr; 67 int port; 68 __be16 *phdr; 69 70 if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN))) 71 return NULL; 72 73 phdr = dsa_etype_header_pos_rx(skb); 74 hdr = ntohs(*phdr); 75 76 /* Remove MTK tag and recalculate checksum. */ 77 skb_pull_rcsum(skb, MTK_HDR_LEN); 78 79 dsa_strip_etype_header(skb, MTK_HDR_LEN); 80 81 /* Get source port information */ 82 port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK); 83 84 skb->dev = dsa_master_find_slave(dev, 0, port); 85 if (!skb->dev) 86 return NULL; 87 88 dsa_default_offload_fwd_mark(skb); 89 90 return skb; 91 } 92 93 static const struct dsa_device_ops mtk_netdev_ops = { 94 .name = "mtk", 95 .proto = DSA_TAG_PROTO_MTK, 96 .xmit = mtk_tag_xmit, 97 .rcv = mtk_tag_rcv, 98 .needed_headroom = MTK_HDR_LEN, 99 }; 100 101 MODULE_LICENSE("GPL"); 102 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK); 103 104 module_dsa_tag_driver(mtk_netdev_ops); 105