summaryrefslogtreecommitdiffstats
path: root/net/dsa/tag_ksz.c
blob: b4872b87d4a6b4971d9ca815be6de3c93ffaab06 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
// SPDX-License-Identifier: GPL-2.0+
/*
 * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
 * Copyright (c) 2017 Microchip Technology
 */

#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <net/dsa.h>
#include "dsa_priv.h"

/* Typically only one byte is used for tail tag. */
#define KSZ_EGRESS_TAG_LEN		1
#define KSZ_INGRESS_TAG_LEN		1

static struct sk_buff *ksz_common_xmit(struct sk_buff *skb,
				       struct net_device *dev, int len)
{
	struct sk_buff *nskb;
	int padlen;

	padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;

	if (skb_tailroom(skb) >= padlen + 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 + 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);
	}

	return nskb;
}

static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
				      struct net_device *dev,
				      unsigned int port, unsigned int len)
{
	skb->dev = dsa_master_find_slave(dev, 0, port);
	if (!skb->dev)
		return NULL;

	pskb_trim_rcsum(skb, skb->len - len);

	skb->offload_fwd_mark = true;

	return skb;
}

/*
 * For Ingress (Host -> KSZ9477), 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 (KSZ9477 -> 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 KSZ9477_INGRESS_TAG_LEN		2
#define KSZ9477_PTP_TAG_LEN		4
#define KSZ9477_PTP_TAG_INDICATION	0x80

#define KSZ9477_TAIL_TAG_OVERRIDE	BIT(9)
#define KSZ9477_TAIL_TAG_LOOKUP		BIT(10)

static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
				    struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	struct sk_buff *nskb;
	u16 *tag;
	u8 *addr;

	nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
	if (!nskb)
		return NULL;

	/* Tag encoding */
	tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN);
	addr = skb_mac_header(nskb);

	*tag = BIT(dp->index);

	if (is_link_local_ether_addr(addr))
		*tag |= KSZ9477_TAIL_TAG_OVERRIDE;

	*tag = cpu_to_be16(*tag);

	return nskb;
}

static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
				   struct packet_type *pt)
{
	/* Tag decoding */
	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
	unsigned int port = tag[0] & 7;
	unsigned int len = KSZ_EGRESS_TAG_LEN;

	/* Extra 4-bytes PTP timestamp */
	if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
		len += KSZ9477_PTP_TAG_LEN;

	return ksz_common_rcv(skb, dev, port, len);
}

static const struct dsa_device_ops ksz9477_netdev_ops = {
	.name	= "ksz9477",
	.proto	= DSA_TAG_PROTO_KSZ9477,
	.xmit	= ksz9477_xmit,
	.rcv	= ksz9477_rcv,
	.overhead = KSZ9477_INGRESS_TAG_LEN,
};

DSA_TAG_DRIVER(ksz9477_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477);

#define KSZ9893_TAIL_TAG_OVERRIDE	BIT(5)
#define KSZ9893_TAIL_TAG_LOOKUP		BIT(6)

static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
				    struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	struct sk_buff *nskb;
	u8 *addr;
	u8 *tag;

	nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
	if (!nskb)
		return NULL;

	/* Tag encoding */
	tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
	addr = skb_mac_header(nskb);

	*tag = BIT(dp->index);

	if (is_link_local_ether_addr(addr))
		*tag |= KSZ9893_TAIL_TAG_OVERRIDE;

	return nskb;
}

static const struct dsa_device_ops ksz9893_netdev_ops = {
	.name	= "ksz9893",
	.proto	= DSA_TAG_PROTO_KSZ9893,
	.xmit	= ksz9893_xmit,
	.rcv	= ksz9477_rcv,
	.overhead = KSZ_INGRESS_TAG_LEN,
};

DSA_TAG_DRIVER(ksz9893_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);

static struct dsa_tag_driver *dsa_tag_driver_array[] = {
	&DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
	&DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
};

module_dsa_tag_drivers(dsa_tag_driver_array);

MODULE_LICENSE("GPL");