1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de> 4 */ 5 #include <linux/dsa/lan9303.h> 6 #include <linux/etherdevice.h> 7 #include <linux/list.h> 8 #include <linux/slab.h> 9 10 #include "tag.h" 11 12 /* To define the outgoing port and to discover the incoming port a regular 13 * VLAN tag is used by the LAN9303. But its VID meaning is 'special': 14 * 15 * Dest MAC Src MAC TAG Type 16 * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |... 17 * |<------->| 18 * TAG: 19 * |<------------->| 20 * | 1 2 | 3 4 | 21 * TPID VID 22 * 0x8100 23 * 24 * VID bit 3 indicates a request for an ALR lookup. 25 * 26 * If VID bit 3 is zero, then bits 0 and 1 specify the destination port 27 * (0, 1, 2) or broadcast (3) or the source port (1, 2). 28 * 29 * VID bit 4 is used to specify if the STP port state should be overridden. 30 * Required when no forwarding between the external ports should happen. 31 */ 32 33 #define LAN9303_NAME "lan9303" 34 35 #define LAN9303_TAG_LEN 4 36 # define LAN9303_TAG_TX_USE_ALR BIT(3) 37 # define LAN9303_TAG_TX_STP_OVERRIDE BIT(4) 38 # define LAN9303_TAG_RX_IGMP BIT(3) 39 # define LAN9303_TAG_RX_STP BIT(4) 40 # define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \ 41 LAN9303_TAG_RX_STP) 42 43 /* Decide whether to transmit using ALR lookup, or transmit directly to 44 * port using tag. ALR learning is performed only when using ALR lookup. 45 * If the two external ports are bridged and the frame is unicast, 46 * then use ALR lookup to allow ALR learning on CPU port. 47 * Otherwise transmit directly to port with STP state override. 48 * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1 49 */ 50 static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr) 51 { 52 struct lan9303 *chip = dp->ds->priv; 53 54 return chip->is_bridged && !is_multicast_ether_addr(dest_addr); 55 } 56 57 static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) 58 { 59 struct dsa_port *dp = dsa_user_to_port(dev); 60 __be16 *lan9303_tag; 61 u16 tag; 62 63 /* provide 'LAN9303_TAG_LEN' bytes additional space */ 64 skb_push(skb, LAN9303_TAG_LEN); 65 66 /* make room between MACs and Ether-Type */ 67 dsa_alloc_etype_header(skb, LAN9303_TAG_LEN); 68 69 lan9303_tag = dsa_etype_header_pos_tx(skb); 70 71 tag = lan9303_xmit_use_arl(dp, skb->data) ? 72 LAN9303_TAG_TX_USE_ALR : 73 dp->index | LAN9303_TAG_TX_STP_OVERRIDE; 74 lan9303_tag[0] = htons(ETH_P_8021Q); 75 lan9303_tag[1] = htons(tag); 76 77 return skb; 78 } 79 80 static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev) 81 { 82 u16 lan9303_tag1; 83 unsigned int source_port; 84 85 if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) { 86 dev_warn_ratelimited(&dev->dev, 87 "Dropping packet, cannot pull\n"); 88 return NULL; 89 } 90 91 if (skb_vlan_tag_present(skb)) { 92 lan9303_tag1 = skb_vlan_tag_get(skb); 93 __vlan_hwaccel_clear_tag(skb); 94 } else { 95 skb_push_rcsum(skb, ETH_HLEN); 96 __skb_vlan_pop(skb, &lan9303_tag1); 97 skb_pull_rcsum(skb, ETH_HLEN); 98 } 99 100 source_port = lan9303_tag1 & 0x3; 101 102 skb->dev = dsa_conduit_find_user(dev, 0, source_port); 103 if (!skb->dev) { 104 dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n"); 105 return NULL; 106 } 107 108 if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU)) 109 dsa_default_offload_fwd_mark(skb); 110 111 return skb; 112 } 113 114 static const struct dsa_device_ops lan9303_netdev_ops = { 115 .name = LAN9303_NAME, 116 .proto = DSA_TAG_PROTO_LAN9303, 117 .xmit = lan9303_xmit, 118 .rcv = lan9303_rcv, 119 .needed_headroom = LAN9303_TAG_LEN, 120 }; 121 122 MODULE_LICENSE("GPL"); 123 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303, LAN9303_NAME); 124 125 module_dsa_tag_driver(lan9303_netdev_ops); 126