// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2022 Schneider Electric * * Clément Léger <clement.leger@bootlin.com> */ #include <linux/bitfield.h> #include <linux/etherdevice.h> #include <linux/if_ether.h> #include <net/dsa.h> #include "tag.h" /* To define the outgoing port and to discover the incoming port a TAG is * inserted after Src MAC : * * Dest MAC Src MAC TAG Type * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 5 6 7 8 | 1 2 |... * |<--------------->| * * See struct a5psw_tag for layout */ #define A5PSW_NAME "a5psw" #define ETH_P_DSA_A5PSW 0xE001 #define A5PSW_TAG_LEN 8 #define A5PSW_CTRL_DATA_FORCE_FORWARD BIT(0) /* This is both used for xmit tag and rcv tagging */ #define A5PSW_CTRL_DATA_PORT GENMASK(3, 0) struct a5psw_tag { __be16 ctrl_tag; __be16 ctrl_data; __be16 ctrl_data2_hi; __be16 ctrl_data2_lo; }; static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_user_to_port(dev); struct a5psw_tag *ptag; u32 data2_val; BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN); /* The Ethernet switch we are interfaced with needs packets to be at * least 60 bytes otherwise they will be discarded when they enter the * switch port logic. */ if (__skb_put_padto(skb, ETH_ZLEN, false)) return NULL; /* provide 'A5PSW_TAG_LEN' bytes additional space */ skb_push(skb, A5PSW_TAG_LEN); /* make room between MACs and Ether-Type to insert tag */ dsa_alloc_etype_header(skb, A5PSW_TAG_LEN); ptag = dsa_etype_header_pos_tx(skb); data2_val = FIELD_PREP(A5PSW_CTRL_DATA_PORT, BIT(dp->index)); ptag->ctrl_tag = htons(ETH_P_DSA_A5PSW); ptag->ctrl_data = htons(A5PSW_CTRL_DATA_FORCE_FORWARD); ptag->ctrl_data2_lo = htons(data2_val); ptag->ctrl_data2_hi = 0; return skb; } static struct sk_buff *a5psw_tag_rcv(struct sk_buff *skb, struct net_device *dev) { struct a5psw_tag *tag; int port; if (unlikely(!pskb_may_pull(skb, A5PSW_TAG_LEN))) { dev_warn_ratelimited(&dev->dev, "Dropping packet, cannot pull\n"); return NULL; } tag = dsa_etype_header_pos_rx(skb); if (tag->ctrl_tag != htons(ETH_P_DSA_A5PSW)) { dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid TAG marker\n"); return NULL; } port = FIELD_GET(A5PSW_CTRL_DATA_PORT, ntohs(tag->ctrl_data)); skb->dev = dsa_conduit_find_user(dev, 0, port); if (!skb->dev) return NULL; skb_pull_rcsum(skb, A5PSW_TAG_LEN); dsa_strip_etype_header(skb, A5PSW_TAG_LEN); dsa_default_offload_fwd_mark(skb); return skb; } static const struct dsa_device_ops a5psw_netdev_ops = { .name = A5PSW_NAME, .proto = DSA_TAG_PROTO_RZN1_A5PSW, .xmit = a5psw_tag_xmit, .rcv = a5psw_tag_rcv, .needed_headroom = A5PSW_TAG_LEN, }; MODULE_LICENSE("GPL v2"); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_A5PSW, A5PSW_NAME); module_dsa_tag_driver(a5psw_netdev_ops);