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 "tag.h" 12 13 #define MTK_NAME "mtk" 14 15 #define MTK_HDR_LEN 4 16 #define MTK_HDR_XMIT_UNTAGGED 0 17 #define MTK_HDR_XMIT_TAGGED_TPID_8100 1 18 #define MTK_HDR_XMIT_TAGGED_TPID_88A8 2 19 #define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0) 20 #define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0) 21 #define MTK_HDR_XMIT_SA_DIS BIT(6) 22 23 static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, 24 struct net_device *dev) 25 { 26 struct dsa_port *dp = dsa_user_to_port(dev); 27 u8 xmit_tpid; 28 u8 *mtk_tag; 29 30 skb_set_queue_mapping(skb, dp->index); 31 32 /* Build the special tag after the MAC Source Address. If VLAN header 33 * is present, it's required that VLAN header and special tag is 34 * being combined. Only in this way we can allow the switch can parse 35 * the both special and VLAN tag at the same time and then look up VLAN 36 * table with VID. 37 */ 38 switch (skb->protocol) { 39 case htons(ETH_P_8021Q): 40 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_8100; 41 break; 42 case htons(ETH_P_8021AD): 43 xmit_tpid = MTK_HDR_XMIT_TAGGED_TPID_88A8; 44 break; 45 default: 46 xmit_tpid = MTK_HDR_XMIT_UNTAGGED; 47 skb_push(skb, MTK_HDR_LEN); 48 dsa_alloc_etype_header(skb, MTK_HDR_LEN); 49 } 50 51 mtk_tag = dsa_etype_header_pos_tx(skb); 52 53 /* Mark tag attribute on special tag insertion to notify hardware 54 * whether that's a combined special tag with 802.1Q header. 55 */ 56 mtk_tag[0] = xmit_tpid; 57 mtk_tag[1] = FIELD_PREP(MTK_HDR_XMIT_DP_BIT_MASK, 58 dsa_xmit_port_mask(skb, dev)); 59 60 /* Tag control information is kept for 802.1Q */ 61 if (xmit_tpid == MTK_HDR_XMIT_UNTAGGED) { 62 mtk_tag[2] = 0; 63 mtk_tag[3] = 0; 64 } 65 66 return skb; 67 } 68 69 static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev) 70 { 71 u16 hdr; 72 int port; 73 __be16 *phdr; 74 75 if (unlikely(!pskb_may_pull(skb, MTK_HDR_LEN))) 76 return NULL; 77 78 phdr = dsa_etype_header_pos_rx(skb); 79 hdr = ntohs(*phdr); 80 81 /* Remove MTK tag and recalculate checksum. */ 82 skb_pull_rcsum(skb, MTK_HDR_LEN); 83 84 dsa_strip_etype_header(skb, MTK_HDR_LEN); 85 86 /* Get source port information */ 87 port = (hdr & MTK_HDR_RECV_SOURCE_PORT_MASK); 88 89 skb->dev = dsa_conduit_find_user(dev, 0, port); 90 if (!skb->dev) 91 return NULL; 92 93 dsa_default_offload_fwd_mark(skb); 94 95 return skb; 96 } 97 98 static const struct dsa_device_ops mtk_netdev_ops = { 99 .name = MTK_NAME, 100 .proto = DSA_TAG_PROTO_MTK, 101 .xmit = mtk_tag_xmit, 102 .rcv = mtk_tag_rcv, 103 .needed_headroom = MTK_HDR_LEN, 104 }; 105 106 MODULE_DESCRIPTION("DSA tag driver for Mediatek switches"); 107 MODULE_LICENSE("GPL"); 108 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK, MTK_NAME); 109 110 module_dsa_tag_driver(mtk_netdev_ops); 111