1 // SPDX-License-Identifier: GPL-2.0+
3 * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
4 * Copyright (c) 2017 Microchip Technology
7 #include <linux/etherdevice.h>
8 #include <linux/list.h>
9 #include <linux/slab.h>
13 /* Typically only one byte is used for tail tag. */
14 #define KSZ_EGRESS_TAG_LEN 1
15 #define KSZ_INGRESS_TAG_LEN 1
17 static struct sk_buff *ksz_common_xmit(struct sk_buff *skb,
18 struct net_device *dev, int len)
23 padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
25 if (skb_tailroom(skb) >= padlen + len) {
26 /* Let dsa_slave_xmit() free skb */
27 if (__skb_put_padto(skb, skb->len + padlen, false))
32 nskb = alloc_skb(NET_IP_ALIGN + skb->len +
33 padlen + len, GFP_ATOMIC);
36 skb_reserve(nskb, NET_IP_ALIGN);
38 skb_reset_mac_header(nskb);
39 skb_set_network_header(nskb,
40 skb_network_header(skb) - skb->head);
41 skb_set_transport_header(nskb,
42 skb_transport_header(skb) - skb->head);
43 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
45 /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free
48 if (skb_put_padto(nskb, nskb->len + padlen))
57 static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
58 struct net_device *dev,
59 unsigned int port, unsigned int len)
61 skb->dev = dsa_master_find_slave(dev, 0, port);
65 pskb_trim_rcsum(skb, skb->len - len);
67 skb->offload_fwd_mark = true;
73 * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
74 * ---------------------------------------------------------------------------
75 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
76 * ---------------------------------------------------------------------------
77 * tag0 : Prioritization (not used now)
78 * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
80 * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
81 * ---------------------------------------------------------------------------
82 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
83 * ---------------------------------------------------------------------------
84 * tag0 : zero-based value represents port
85 * (eg, 0x00=port1, 0x02=port3, 0x06=port7)
88 #define KSZ9477_INGRESS_TAG_LEN 2
89 #define KSZ9477_PTP_TAG_LEN 4
90 #define KSZ9477_PTP_TAG_INDICATION 0x80
92 #define KSZ9477_TAIL_TAG_OVERRIDE BIT(9)
93 #define KSZ9477_TAIL_TAG_LOOKUP BIT(10)
95 static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
96 struct net_device *dev)
98 struct dsa_port *dp = dsa_slave_to_port(dev);
103 nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
108 tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN);
109 addr = skb_mac_header(nskb);
111 *tag = BIT(dp->index);
113 if (is_link_local_ether_addr(addr))
114 *tag |= KSZ9477_TAIL_TAG_OVERRIDE;
116 *tag = cpu_to_be16(*tag);
121 static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
122 struct packet_type *pt)
125 u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
126 unsigned int port = tag[0] & 7;
127 unsigned int len = KSZ_EGRESS_TAG_LEN;
129 /* Extra 4-bytes PTP timestamp */
130 if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
131 len += KSZ9477_PTP_TAG_LEN;
133 return ksz_common_rcv(skb, dev, port, len);
136 const struct dsa_device_ops ksz9477_netdev_ops = {
137 .xmit = ksz9477_xmit,
139 .overhead = KSZ9477_INGRESS_TAG_LEN,
142 #define KSZ9893_TAIL_TAG_OVERRIDE BIT(5)
143 #define KSZ9893_TAIL_TAG_LOOKUP BIT(6)
145 static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
146 struct net_device *dev)
148 struct dsa_port *dp = dsa_slave_to_port(dev);
149 struct sk_buff *nskb;
153 nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
158 tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
159 addr = skb_mac_header(nskb);
161 *tag = BIT(dp->index);
163 if (is_link_local_ether_addr(addr))
164 *tag |= KSZ9893_TAIL_TAG_OVERRIDE;
169 const struct dsa_device_ops ksz9893_netdev_ops = {
170 .xmit = ksz9893_xmit,
172 .overhead = KSZ_INGRESS_TAG_LEN,