| /* |
| * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * 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/dsa/lan9303.h> |
| #include <linux/etherdevice.h> |
| #include <linux/list.h> |
| #include <linux/slab.h> |
| |
| #include "dsa_priv.h" |
| |
| /* To define the outgoing port and to discover the incoming port a regular |
| * VLAN tag is used by the LAN9303. But its VID meaning is 'special': |
| * |
| * Dest MAC Src MAC TAG Type |
| * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |... |
| * |<------->| |
| * TAG: |
| * |<------------->| |
| * | 1 2 | 3 4 | |
| * TPID VID |
| * 0x8100 |
| * |
| * VID bit 3 indicates a request for an ALR lookup. |
| * |
| * If VID bit 3 is zero, then bits 0 and 1 specify the destination port |
| * (0, 1, 2) or broadcast (3) or the source port (1, 2). |
| * |
| * VID bit 4 is used to specify if the STP port state should be overridden. |
| * Required when no forwarding between the external ports should happen. |
| */ |
| |
| #define LAN9303_TAG_LEN 4 |
| # define LAN9303_TAG_TX_USE_ALR BIT(3) |
| # define LAN9303_TAG_TX_STP_OVERRIDE BIT(4) |
| # define LAN9303_TAG_RX_IGMP BIT(3) |
| # define LAN9303_TAG_RX_STP BIT(4) |
| # define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \ |
| LAN9303_TAG_RX_STP) |
| |
| /* Decide whether to transmit using ALR lookup, or transmit directly to |
| * port using tag. ALR learning is performed only when using ALR lookup. |
| * If the two external ports are bridged and the frame is unicast, |
| * then use ALR lookup to allow ALR learning on CPU port. |
| * Otherwise transmit directly to port with STP state override. |
| * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1 |
| */ |
| static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr) |
| { |
| struct lan9303 *chip = dp->ds->priv; |
| |
| return chip->is_bridged && !is_multicast_ether_addr(dest_addr); |
| } |
| |
| static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) |
| { |
| struct dsa_port *dp = dsa_slave_to_port(dev); |
| u16 *lan9303_tag; |
| |
| /* insert a special VLAN tag between the MAC addresses |
| * and the current ethertype field. |
| */ |
| if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) { |
| dev_dbg(&dev->dev, |
| "Cannot make room for the special tag. Dropping packet\n"); |
| return NULL; |
| } |
| |
| /* provide 'LAN9303_TAG_LEN' bytes additional space */ |
| skb_push(skb, LAN9303_TAG_LEN); |
| |
| /* make room between MACs and Ether-Type */ |
| memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN); |
| |
| lan9303_tag = (u16 *)(skb->data + 2 * ETH_ALEN); |
| lan9303_tag[0] = htons(ETH_P_8021Q); |
| lan9303_tag[1] = lan9303_xmit_use_arl(dp, skb->data) ? |
| LAN9303_TAG_TX_USE_ALR : |
| dp->index | LAN9303_TAG_TX_STP_OVERRIDE; |
| lan9303_tag[1] = htons(lan9303_tag[1]); |
| |
| return skb; |
| } |
| |
| static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev, |
| struct packet_type *pt) |
| { |
| u16 *lan9303_tag; |
| u16 lan9303_tag1; |
| unsigned int source_port; |
| |
| if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) { |
| dev_warn_ratelimited(&dev->dev, |
| "Dropping packet, cannot pull\n"); |
| return NULL; |
| } |
| |
| /* '->data' points into the middle of our special VLAN tag information: |
| * |
| * ~ MAC src | 0x81 | 0x00 | 0xyy | 0xzz | ether type |
| * ^ |
| * ->data |
| */ |
| lan9303_tag = (u16 *)(skb->data - 2); |
| |
| if (lan9303_tag[0] != htons(ETH_P_8021Q)) { |
| dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n"); |
| return NULL; |
| } |
| |
| lan9303_tag1 = ntohs(lan9303_tag[1]); |
| source_port = lan9303_tag1 & 0x3; |
| |
| skb->dev = dsa_master_find_slave(dev, 0, source_port); |
| if (!skb->dev) { |
| dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n"); |
| return NULL; |
| } |
| |
| /* remove the special VLAN tag between the MAC addresses |
| * and the current ethertype field. |
| */ |
| skb_pull_rcsum(skb, 2 + 2); |
| memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN), |
| 2 * ETH_ALEN); |
| skb->offload_fwd_mark = !(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU); |
| |
| return skb; |
| } |
| |
| const struct dsa_device_ops lan9303_netdev_ops = { |
| .xmit = lan9303_xmit, |
| .rcv = lan9303_rcv, |
| .overhead = LAN9303_TAG_LEN, |
| }; |