1 // SPDX-License-Identifier: (GPL-2.0 OR MIT) 2 /* 3 * net/dsa/tag_hellcreek.c - Hirschmann Hellcreek switch tag format handling 4 * 5 * Copyright (C) 2019,2020 Linutronix GmbH 6 * Author Kurt Kanzenbach <kurt@linutronix.de> 7 * 8 * Based on tag_ksz.c. 9 */ 10 11 #include <linux/skbuff.h> 12 #include <net/dsa.h> 13 14 #include "dsa_priv.h" 15 16 #define HELLCREEK_TAG_LEN 1 17 18 static struct sk_buff *hellcreek_xmit(struct sk_buff *skb, 19 struct net_device *dev) 20 { 21 struct dsa_port *dp = dsa_slave_to_port(dev); 22 u8 *tag; 23 24 /* Tag encoding */ 25 tag = skb_put(skb, HELLCREEK_TAG_LEN); 26 *tag = BIT(dp->index); 27 28 return skb; 29 } 30 31 static struct sk_buff *hellcreek_rcv(struct sk_buff *skb, 32 struct net_device *dev, 33 struct packet_type *pt) 34 { 35 /* Tag decoding */ 36 u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN; 37 unsigned int port = tag[0] & 0x03; 38 39 skb->dev = dsa_master_find_slave(dev, 0, port); 40 if (!skb->dev) { 41 netdev_warn(dev, "Failed to get source port: %d\n", port); 42 return NULL; 43 } 44 45 pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN); 46 47 skb->offload_fwd_mark = true; 48 49 return skb; 50 } 51 52 static const struct dsa_device_ops hellcreek_netdev_ops = { 53 .name = "hellcreek", 54 .proto = DSA_TAG_PROTO_HELLCREEK, 55 .xmit = hellcreek_xmit, 56 .rcv = hellcreek_rcv, 57 .overhead = HELLCREEK_TAG_LEN, 58 .tail_tag = true, 59 }; 60 61 MODULE_LICENSE("Dual MIT/GPL"); 62 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK); 63 64 module_dsa_tag_driver(hellcreek_netdev_ops); 65