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 { 34 /* Tag decoding */ 35 u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN; 36 unsigned int port = tag[0] & 0x03; 37 38 skb->dev = dsa_master_find_slave(dev, 0, port); 39 if (!skb->dev) { 40 netdev_warn(dev, "Failed to get source port: %d\n", port); 41 return NULL; 42 } 43 44 pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN); 45 46 dsa_default_offload_fwd_mark(skb); 47 48 return skb; 49 } 50 51 static const struct dsa_device_ops hellcreek_netdev_ops = { 52 .name = "hellcreek", 53 .proto = DSA_TAG_PROTO_HELLCREEK, 54 .xmit = hellcreek_xmit, 55 .rcv = hellcreek_rcv, 56 .needed_tailroom = HELLCREEK_TAG_LEN, 57 }; 58 59 MODULE_LICENSE("Dual MIT/GPL"); 60 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK); 61 62 module_dsa_tag_driver(hellcreek_netdev_ops); 63