diff options
Diffstat (limited to 'net/dsa/tag_hellcreek.c')
-rw-r--r-- | net/dsa/tag_hellcreek.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/net/dsa/tag_hellcreek.c b/net/dsa/tag_hellcreek.c new file mode 100644 index 000000000..53a206d11 --- /dev/null +++ b/net/dsa/tag_hellcreek.c @@ -0,0 +1,71 @@ +// 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_once(dev, "Failed to get source port: %d\n", port); + return NULL; + } + + if (pskb_trim_rcsum(skb, skb->len - HELLCREEK_TAG_LEN)) + return NULL; + + 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); |