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_xmit(struct sk_buff *skb,
 18				       struct net_device *dev, int len)
 19{
 20	struct sk_buff *nskb;
 21	int padlen;
 22
 23	padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
 24
 25	if (skb_tailroom(skb) >= padlen + len) {
 26		/* Let dsa_slave_xmit() free skb */
 27		if (__skb_put_padto(skb, skb->len + padlen, false))
 28			return NULL;
 29
 30		nskb = skb;
 31	} else {
 32		nskb = alloc_skb(NET_IP_ALIGN + skb->len +
 33				 padlen + len, GFP_ATOMIC);
 34		if (!nskb)
 35			return NULL;
 36		skb_reserve(nskb, NET_IP_ALIGN);
 37
 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));
 44
 45		/* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free
 46		 * skb
 47		 */
 48		if (skb_put_padto(nskb, nskb->len + padlen))
 49			return NULL;
 50
 51		consume_skb(skb);
 52	}
 53
 54	return nskb;
 55}
 56
 57static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
 58				      struct net_device *dev,
 59				      unsigned int port, unsigned int len)
 60{
 61	skb->dev = dsa_master_find_slave(dev, 0, port);
 62	if (!skb->dev)
 63		return NULL;
 64
 65	pskb_trim_rcsum(skb, skb->len - len);
 66
 67	skb->offload_fwd_mark = true;
 68
 69	return skb;
 70}
 71
 72/*
 73 * For Ingress (Host -> KSZ8795), 1 byte is added before FCS.
 74 * ---------------------------------------------------------------------------
 75 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag(1byte)|FCS(4bytes)
 76 * ---------------------------------------------------------------------------
 77 * tag : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
 78 *
 79 * For Egress (KSZ8795 -> Host), 1 byte is added before FCS.
 80 * ---------------------------------------------------------------------------
 81 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
 82 * ---------------------------------------------------------------------------
 83 * tag0 : zero-based value represents port
 84 *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
 85 */
 86
 87#define KSZ8795_TAIL_TAG_OVERRIDE	BIT(6)
 88#define KSZ8795_TAIL_TAG_LOOKUP		BIT(7)
 89
 90static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
 91{
 92	struct dsa_port *dp = dsa_slave_to_port(dev);
 93	struct sk_buff *nskb;
 94	u8 *tag;
 95	u8 *addr;
 96
 97	nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
 98	if (!nskb)
 99		return NULL;
100
101	/* Tag encoding */
102	tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
103	addr = skb_mac_header(nskb);
104
105	*tag = 1 << dp->index;
106	if (is_link_local_ether_addr(addr))
107		*tag |= KSZ8795_TAIL_TAG_OVERRIDE;
108
109	return nskb;
110}
111
112static struct sk_buff *ksz8795_rcv(struct sk_buff *skb, struct net_device *dev,
113				  struct packet_type *pt)
114{
115	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
116
117	return ksz_common_rcv(skb, dev, tag[0] & 7, KSZ_EGRESS_TAG_LEN);
118}
119
120static const struct dsa_device_ops ksz8795_netdev_ops = {
121	.name	= "ksz8795",
122	.proto	= DSA_TAG_PROTO_KSZ8795,
123	.xmit	= ksz8795_xmit,
124	.rcv	= ksz8795_rcv,
125	.overhead = KSZ_INGRESS_TAG_LEN,
126};
127
128DSA_TAG_DRIVER(ksz8795_netdev_ops);
129MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ8795);
130
131/*
132 * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
133 * ---------------------------------------------------------------------------
134 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
135 * ---------------------------------------------------------------------------
136 * tag0 : Prioritization (not used now)
137 * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
138 *
139 * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
140 * ---------------------------------------------------------------------------
141 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
142 * ---------------------------------------------------------------------------
143 * tag0 : zero-based value represents port
144 *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
145 */
146
147#define KSZ9477_INGRESS_TAG_LEN		2
148#define KSZ9477_PTP_TAG_LEN		4
149#define KSZ9477_PTP_TAG_INDICATION	0x80
150
151#define KSZ9477_TAIL_TAG_OVERRIDE	BIT(9)
152#define KSZ9477_TAIL_TAG_LOOKUP		BIT(10)
153
154static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
155				    struct net_device *dev)
156{
157	struct dsa_port *dp = dsa_slave_to_port(dev);
158	struct sk_buff *nskb;
159	__be16 *tag;
160	u8 *addr;
161	u16 val;
162
163	nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
164	if (!nskb)
165		return NULL;
166
167	/* Tag encoding */
168	tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN);
169	addr = skb_mac_header(nskb);
170
171	val = BIT(dp->index);
172
173	if (is_link_local_ether_addr(addr))
174		val |= KSZ9477_TAIL_TAG_OVERRIDE;
175
176	*tag = cpu_to_be16(val);
177
178	return nskb;
179}
180
181static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
182				   struct packet_type *pt)
183{
184	/* Tag decoding */
185	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
186	unsigned int port = tag[0] & 7;
187	unsigned int len = KSZ_EGRESS_TAG_LEN;
188
189	/* Extra 4-bytes PTP timestamp */
190	if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
191		len += KSZ9477_PTP_TAG_LEN;
192
193	return ksz_common_rcv(skb, dev, port, len);
194}
195
196static const struct dsa_device_ops ksz9477_netdev_ops = {
197	.name	= "ksz9477",
198	.proto	= DSA_TAG_PROTO_KSZ9477,
199	.xmit	= ksz9477_xmit,
200	.rcv	= ksz9477_rcv,
201	.overhead = KSZ9477_INGRESS_TAG_LEN,
202};
203
204DSA_TAG_DRIVER(ksz9477_netdev_ops);
205MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477);
206
207#define KSZ9893_TAIL_TAG_OVERRIDE	BIT(5)
208#define KSZ9893_TAIL_TAG_LOOKUP		BIT(6)
209
210static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
211				    struct net_device *dev)
212{
213	struct dsa_port *dp = dsa_slave_to_port(dev);
214	struct sk_buff *nskb;
215	u8 *addr;
216	u8 *tag;
217
218	nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
219	if (!nskb)
220		return NULL;
221
222	/* Tag encoding */
223	tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
224	addr = skb_mac_header(nskb);
225
226	*tag = BIT(dp->index);
227
228	if (is_link_local_ether_addr(addr))
229		*tag |= KSZ9893_TAIL_TAG_OVERRIDE;
230
231	return nskb;
232}
233
234static const struct dsa_device_ops ksz9893_netdev_ops = {
235	.name	= "ksz9893",
236	.proto	= DSA_TAG_PROTO_KSZ9893,
237	.xmit	= ksz9893_xmit,
238	.rcv	= ksz9477_rcv,
239	.overhead = KSZ_INGRESS_TAG_LEN,
240};
241
242DSA_TAG_DRIVER(ksz9893_netdev_ops);
243MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);
244
245static struct dsa_tag_driver *dsa_tag_driver_array[] = {
246	&DSA_TAG_DRIVER_NAME(ksz8795_netdev_ops),
247	&DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
248	&DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
249};
250
251module_dsa_tag_drivers(dsa_tag_driver_array);
252
253MODULE_LICENSE("GPL");