| /* |
| * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling |
| * Copyright (c) 2017 Microchip Technology |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| */ |
| |
| #include <linux/etherdevice.h> |
| #include <linux/list.h> |
| #include <linux/slab.h> |
| #include <net/dsa.h> |
| #include "dsa_priv.h" |
| |
| /* For Ingress (Host -> KSZ), 2 bytes are added before FCS. |
| * --------------------------------------------------------------------------- |
| * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes) |
| * --------------------------------------------------------------------------- |
| * tag0 : Prioritization (not used now) |
| * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5) |
| * |
| * For Egress (KSZ -> Host), 1 byte is added before FCS. |
| * --------------------------------------------------------------------------- |
| * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes) |
| * --------------------------------------------------------------------------- |
| * tag0 : zero-based value represents port |
| * (eg, 0x00=port1, 0x02=port3, 0x06=port7) |
| */ |
| |
| #define KSZ_INGRESS_TAG_LEN 2 |
| #define KSZ_EGRESS_TAG_LEN 1 |
| |
| static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev) |
| { |
| struct dsa_port *dp = dsa_slave_to_port(dev); |
| struct sk_buff *nskb; |
| int padlen; |
| u8 *tag; |
| |
| padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len; |
| |
| if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) { |
| /* Let dsa_slave_xmit() free skb */ |
| if (__skb_put_padto(skb, skb->len + padlen, false)) |
| return NULL; |
| |
| nskb = skb; |
| } else { |
| nskb = alloc_skb(NET_IP_ALIGN + skb->len + |
| padlen + KSZ_INGRESS_TAG_LEN, GFP_ATOMIC); |
| if (!nskb) |
| return NULL; |
| skb_reserve(nskb, NET_IP_ALIGN); |
| |
| skb_reset_mac_header(nskb); |
| skb_set_network_header(nskb, |
| skb_network_header(skb) - skb->head); |
| skb_set_transport_header(nskb, |
| skb_transport_header(skb) - skb->head); |
| skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); |
| |
| /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free |
| * skb |
| */ |
| if (skb_put_padto(nskb, nskb->len + padlen)) |
| return NULL; |
| |
| consume_skb(skb); |
| } |
| |
| tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); |
| tag[0] = 0; |
| tag[1] = 1 << dp->index; /* destination port */ |
| |
| return nskb; |
| } |
| |
| static struct sk_buff *ksz_rcv(struct sk_buff *skb, struct net_device *dev, |
| struct packet_type *pt) |
| { |
| u8 *tag; |
| int source_port; |
| |
| tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN; |
| |
| source_port = tag[0] & 7; |
| |
| skb->dev = dsa_master_find_slave(dev, 0, source_port); |
| if (!skb->dev) |
| return NULL; |
| |
| pskb_trim_rcsum(skb, skb->len - KSZ_EGRESS_TAG_LEN); |
| |
| return skb; |
| } |
| |
| const struct dsa_device_ops ksz_netdev_ops = { |
| .xmit = ksz_xmit, |
| .rcv = ksz_rcv, |
| }; |