| // SPDX-License-Identifier: (GPL-2.0 OR MIT) |
| /* |
| * net/dsa/tag_hellcreek.c - Hirschmann Hellcreek switch tag format handling |
| * |
| * Copyright (C) 2019,2020 Linutronix GmbH |
| * Author Kurt Kanzenbach <kurt@linutronix.de> |
| * |
| * Based on tag_ksz.c. |
| */ |
| |
| #include <linux/skbuff.h> |
| #include <net/dsa.h> |
| |
| #include "dsa_priv.h" |
| |
| #define HELLCREEK_TAG_LEN 1 |
| |
| static struct sk_buff *hellcreek_xmit(struct sk_buff *skb, |
| struct net_device *dev) |
| { |
| struct dsa_port *dp = dsa_slave_to_port(dev); |
| u8 *tag; |
| |
| /* Calculate checksums (if required) before adding the trailer tag to |
| * avoid including it in calculations. That would lead to wrong |
| * checksums after the switch strips the tag. |
| */ |
| if (skb->ip_summed == CHECKSUM_PARTIAL && |
| skb_checksum_help(skb)) |
| return NULL; |
| |
| /* Tag encoding */ |
| tag = skb_put(skb, HELLCREEK_TAG_LEN); |
| *tag = BIT(dp->index); |
| |
| return skb; |
| } |
| |
| static struct sk_buff *hellcreek_rcv(struct sk_buff *skb, |
| struct net_device *dev) |
| { |
| /* Tag decoding */ |
| u8 *tag = skb_tail_pointer(skb) - HELLCREEK_TAG_LEN; |
| unsigned int port = tag[0] & 0x03; |
| |
| skb->dev = dsa_master_find_slave(dev, 0, port); |
| if (!skb->dev) { |
| netdev_warn(dev, "Failed to get source port: %d\n", port); |
| return NULL; |
| } |
| |
| pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN); |
| |
| dsa_default_offload_fwd_mark(skb); |
| |
| return skb; |
| } |
| |
| static const struct dsa_device_ops hellcreek_netdev_ops = { |
| .name = "hellcreek", |
| .proto = DSA_TAG_PROTO_HELLCREEK, |
| .xmit = hellcreek_xmit, |
| .rcv = hellcreek_rcv, |
| .needed_tailroom = HELLCREEK_TAG_LEN, |
| }; |
| |
| MODULE_LICENSE("Dual MIT/GPL"); |
| MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_HELLCREEK); |
| |
| module_dsa_tag_driver(hellcreek_netdev_ops); |