1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
  4 * Copyright (c) 2017 Microchip Technology
  5 */
  6
  7#include <linux/etherdevice.h>
  8#include <linux/list.h>
  9#include <linux/slab.h>
 10#include <net/dsa.h>
 11#include "dsa_priv.h"
 12
 13/* Typically only one byte is used for tail tag. */
 14#define KSZ_EGRESS_TAG_LEN		1
 15#define KSZ_INGRESS_TAG_LEN		1
 16
 17static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
 18				      struct net_device *dev,
 19				      unsigned int port, unsigned int len)
 20{
 21	skb->dev = dsa_master_find_slave(dev, 0, port);
 22	if (!skb->dev)
 23		return NULL;
 24
 25	pskb_trim_rcsum(skb, skb->len - len);
 26
 27	skb->offload_fwd_mark = true;
 28
 29	return skb;
 30}
 31
 32/*
 33 * For Ingress (Host -> KSZ8795), 1 byte is added before FCS.
 34 * ---------------------------------------------------------------------------
 35 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag(1byte)|FCS(4bytes)
 36 * ---------------------------------------------------------------------------
 37 * tag : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
 38 *
 39 * For Egress (KSZ8795 -> Host), 1 byte is added before FCS.
 40 * ---------------------------------------------------------------------------
 41 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
 42 * ---------------------------------------------------------------------------
 43 * tag0 : zero-based value represents port
 44 *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
 45 */
 46
 47#define KSZ8795_TAIL_TAG_OVERRIDE	BIT(6)
 48#define KSZ8795_TAIL_TAG_LOOKUP		BIT(7)
 49
 50static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
 51{
 52	struct dsa_port *dp = dsa_slave_to_port(dev);
 53	u8 *tag;
 54	u8 *addr;
 55
 56	if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
 57		return NULL;
 58
 59	/* Tag encoding */
 60	tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
 61	addr = skb_mac_header(skb);
 62
 63	*tag = 1 << dp->index;
 64	if (is_link_local_ether_addr(addr))
 65		*tag |= KSZ8795_TAIL_TAG_OVERRIDE;
 66
 67	return skb;
 68}
 69
 70static struct sk_buff *ksz8795_rcv(struct sk_buff *skb, struct net_device *dev,
 71				  struct packet_type *pt)
 72{
 73	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
 74
 75	return ksz_common_rcv(skb, dev, tag[0] & 7, KSZ_EGRESS_TAG_LEN);
 76}
 77
 78static const struct dsa_device_ops ksz8795_netdev_ops = {
 79	.name	= "ksz8795",
 80	.proto	= DSA_TAG_PROTO_KSZ8795,
 81	.xmit	= ksz8795_xmit,
 82	.rcv	= ksz8795_rcv,
 83	.needed_tailroom = KSZ_INGRESS_TAG_LEN,
 84};
 85
 86DSA_TAG_DRIVER(ksz8795_netdev_ops);
 87MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ8795);
 88
 89/*
 90 * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
 91 * ---------------------------------------------------------------------------
 92 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
 93 * ---------------------------------------------------------------------------
 94 * tag0 : Prioritization (not used now)
 95 * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
 96 *
 97 * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
 98 * ---------------------------------------------------------------------------
 99 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
100 * ---------------------------------------------------------------------------
101 * tag0 : zero-based value represents port
102 *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
103 */
104
105#define KSZ9477_INGRESS_TAG_LEN		2
106#define KSZ9477_PTP_TAG_LEN		4
107#define KSZ9477_PTP_TAG_INDICATION	0x80
108
109#define KSZ9477_TAIL_TAG_OVERRIDE	BIT(9)
110#define KSZ9477_TAIL_TAG_LOOKUP		BIT(10)
111
112static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
113				    struct net_device *dev)
114{
115	struct dsa_port *dp = dsa_slave_to_port(dev);
116	__be16 *tag;
117	u8 *addr;
118	u16 val;
119
120	if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
121		return NULL;
122
123	/* Tag encoding */
124	tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN);
125	addr = skb_mac_header(skb);
126
127	val = BIT(dp->index);
128
129	if (is_link_local_ether_addr(addr))
130		val |= KSZ9477_TAIL_TAG_OVERRIDE;
131
132	*tag = cpu_to_be16(val);
133
134	return skb;
135}
136
137static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
138				   struct packet_type *pt)
139{
140	/* Tag decoding */
141	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
142	unsigned int port = tag[0] & 7;
143	unsigned int len = KSZ_EGRESS_TAG_LEN;
144
145	/* Extra 4-bytes PTP timestamp */
146	if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
147		len += KSZ9477_PTP_TAG_LEN;
148
149	return ksz_common_rcv(skb, dev, port, len);
150}
151
152static const struct dsa_device_ops ksz9477_netdev_ops = {
153	.name	= "ksz9477",
154	.proto	= DSA_TAG_PROTO_KSZ9477,
155	.xmit	= ksz9477_xmit,
156	.rcv	= ksz9477_rcv,
157	.needed_tailroom = KSZ9477_INGRESS_TAG_LEN,
158};
159
160DSA_TAG_DRIVER(ksz9477_netdev_ops);
161MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477);
162
163#define KSZ9893_TAIL_TAG_OVERRIDE	BIT(5)
164#define KSZ9893_TAIL_TAG_LOOKUP		BIT(6)
165
166static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
167				    struct net_device *dev)
168{
169	struct dsa_port *dp = dsa_slave_to_port(dev);
170	u8 *addr;
171	u8 *tag;
172
173	if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
174		return NULL;
175
176	/* Tag encoding */
177	tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
178	addr = skb_mac_header(skb);
179
180	*tag = BIT(dp->index);
181
182	if (is_link_local_ether_addr(addr))
183		*tag |= KSZ9893_TAIL_TAG_OVERRIDE;
184
185	return skb;
186}
187
188static const struct dsa_device_ops ksz9893_netdev_ops = {
189	.name	= "ksz9893",
190	.proto	= DSA_TAG_PROTO_KSZ9893,
191	.xmit	= ksz9893_xmit,
192	.rcv	= ksz9477_rcv,
193	.needed_tailroom = KSZ_INGRESS_TAG_LEN,
194};
195
196DSA_TAG_DRIVER(ksz9893_netdev_ops);
197MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);
198
199static struct dsa_tag_driver *dsa_tag_driver_array[] = {
200	&DSA_TAG_DRIVER_NAME(ksz8795_netdev_ops),
201	&DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
202	&DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
203};
204
205module_dsa_tag_drivers(dsa_tag_driver_array);
206
207MODULE_LICENSE("GPL");