xref: /openbmc/linux/net/dsa/tag_ocelot.c (revision dc3401c8)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2019 NXP Semiconductors
3  */
4 #include <linux/dsa/ocelot.h>
5 #include <soc/mscc/ocelot.h>
6 #include "dsa_priv.h"
7 
8 static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
9 			       __be32 ifh_prefix, void **ifh)
10 {
11 	struct dsa_port *dp = dsa_slave_to_port(netdev);
12 	struct dsa_switch *ds = dp->ds;
13 	void *injection;
14 	__be32 *prefix;
15 	u32 rew_op = 0;
16 
17 	injection = skb_push(skb, OCELOT_TAG_LEN);
18 	prefix = skb_push(skb, OCELOT_SHORT_PREFIX_LEN);
19 
20 	*prefix = ifh_prefix;
21 	memset(injection, 0, OCELOT_TAG_LEN);
22 	ocelot_ifh_set_bypass(injection, 1);
23 	ocelot_ifh_set_src(injection, ds->num_ports);
24 	ocelot_ifh_set_qos_class(injection, skb->priority);
25 
26 	rew_op = ocelot_ptp_rew_op(skb);
27 	if (rew_op)
28 		ocelot_ifh_set_rew_op(injection, rew_op);
29 
30 	*ifh = injection;
31 }
32 
33 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
34 				   struct net_device *netdev)
35 {
36 	struct dsa_port *dp = dsa_slave_to_port(netdev);
37 	void *injection;
38 
39 	ocelot_xmit_common(skb, netdev, cpu_to_be32(0x8880000a), &injection);
40 	ocelot_ifh_set_dest(injection, BIT_ULL(dp->index));
41 
42 	return skb;
43 }
44 
45 static struct sk_buff *seville_xmit(struct sk_buff *skb,
46 				    struct net_device *netdev)
47 {
48 	struct dsa_port *dp = dsa_slave_to_port(netdev);
49 	void *injection;
50 
51 	ocelot_xmit_common(skb, netdev, cpu_to_be32(0x88800005), &injection);
52 	seville_ifh_set_dest(injection, BIT_ULL(dp->index));
53 
54 	return skb;
55 }
56 
57 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
58 				  struct net_device *netdev)
59 {
60 	u64 src_port, qos_class;
61 	u64 vlan_tci, tag_type;
62 	u8 *start = skb->data;
63 	struct dsa_port *dp;
64 	u8 *extraction;
65 	u16 vlan_tpid;
66 
67 	/* Revert skb->data by the amount consumed by the DSA master,
68 	 * so it points to the beginning of the frame.
69 	 */
70 	skb_push(skb, ETH_HLEN);
71 	/* We don't care about the short prefix, it is just for easy entrance
72 	 * into the DSA master's RX filter. Discard it now by moving it into
73 	 * the headroom.
74 	 */
75 	skb_pull(skb, OCELOT_SHORT_PREFIX_LEN);
76 	/* And skb->data now points to the extraction frame header.
77 	 * Keep a pointer to it.
78 	 */
79 	extraction = skb->data;
80 	/* Now the EFH is part of the headroom as well */
81 	skb_pull(skb, OCELOT_TAG_LEN);
82 	/* Reset the pointer to the real MAC header */
83 	skb_reset_mac_header(skb);
84 	skb_reset_mac_len(skb);
85 	/* And move skb->data to the correct location again */
86 	skb_pull(skb, ETH_HLEN);
87 
88 	/* Remove from inet csum the extraction header */
89 	skb_postpull_rcsum(skb, start, OCELOT_TOTAL_TAG_LEN);
90 
91 	ocelot_xfh_get_src_port(extraction, &src_port);
92 	ocelot_xfh_get_qos_class(extraction, &qos_class);
93 	ocelot_xfh_get_tag_type(extraction, &tag_type);
94 	ocelot_xfh_get_vlan_tci(extraction, &vlan_tci);
95 
96 	skb->dev = dsa_master_find_slave(netdev, 0, src_port);
97 	if (!skb->dev)
98 		/* The switch will reflect back some frames sent through
99 		 * sockets opened on the bare DSA master. These will come back
100 		 * with src_port equal to the index of the CPU port, for which
101 		 * there is no slave registered. So don't print any error
102 		 * message here (ignore and drop those frames).
103 		 */
104 		return NULL;
105 
106 	dsa_default_offload_fwd_mark(skb);
107 	skb->priority = qos_class;
108 
109 	/* Ocelot switches copy frames unmodified to the CPU. However, it is
110 	 * possible for the user to request a VLAN modification through
111 	 * VCAP_IS1_ACT_VID_REPLACE_ENA. In this case, what will happen is that
112 	 * the VLAN ID field from the Extraction Header gets updated, but the
113 	 * 802.1Q header does not (the classified VLAN only becomes visible on
114 	 * egress through the "port tag" of front-panel ports).
115 	 * So, for traffic extracted by the CPU, we want to pick up the
116 	 * classified VLAN and manually replace the existing 802.1Q header from
117 	 * the packet with it, so that the operating system is always up to
118 	 * date with the result of tc-vlan actions.
119 	 * NOTE: In VLAN-unaware mode, we don't want to do that, we want the
120 	 * frame to remain unmodified, because the classified VLAN is always
121 	 * equal to the pvid of the ingress port and should not be used for
122 	 * processing.
123 	 */
124 	dp = dsa_slave_to_port(skb->dev);
125 	vlan_tpid = tag_type ? ETH_P_8021AD : ETH_P_8021Q;
126 
127 	if (dsa_port_is_vlan_filtering(dp) &&
128 	    eth_hdr(skb)->h_proto == htons(vlan_tpid)) {
129 		u16 dummy_vlan_tci;
130 
131 		skb_push_rcsum(skb, ETH_HLEN);
132 		__skb_vlan_pop(skb, &dummy_vlan_tci);
133 		skb_pull_rcsum(skb, ETH_HLEN);
134 		__vlan_hwaccel_put_tag(skb, htons(vlan_tpid), vlan_tci);
135 	}
136 
137 	return skb;
138 }
139 
140 static const struct dsa_device_ops ocelot_netdev_ops = {
141 	.name			= "ocelot",
142 	.proto			= DSA_TAG_PROTO_OCELOT,
143 	.xmit			= ocelot_xmit,
144 	.rcv			= ocelot_rcv,
145 	.needed_headroom	= OCELOT_TOTAL_TAG_LEN,
146 	.promisc_on_master	= true,
147 };
148 
149 DSA_TAG_DRIVER(ocelot_netdev_ops);
150 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT);
151 
152 static const struct dsa_device_ops seville_netdev_ops = {
153 	.name			= "seville",
154 	.proto			= DSA_TAG_PROTO_SEVILLE,
155 	.xmit			= seville_xmit,
156 	.rcv			= ocelot_rcv,
157 	.needed_headroom	= OCELOT_TOTAL_TAG_LEN,
158 	.promisc_on_master	= true,
159 };
160 
161 DSA_TAG_DRIVER(seville_netdev_ops);
162 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SEVILLE);
163 
164 static struct dsa_tag_driver *ocelot_tag_driver_array[] = {
165 	&DSA_TAG_DRIVER_NAME(ocelot_netdev_ops),
166 	&DSA_TAG_DRIVER_NAME(seville_netdev_ops),
167 };
168 
169 module_dsa_tag_drivers(ocelot_tag_driver_array);
170 
171 MODULE_LICENSE("GPL v2");
172