xref: /openbmc/linux/net/dsa/tag_ocelot.c (revision 015d239a)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2019 NXP Semiconductors
3  */
4 #include <soc/mscc/ocelot.h>
5 #include <linux/packing.h>
6 #include "dsa_priv.h"
7 
8 /* The CPU injection header and the CPU extraction header can have 3 types of
9  * prefixes: long, short and no prefix. The format of the header itself is the
10  * same in all 3 cases.
11  *
12  * Extraction with long prefix:
13  *
14  * +-------------------+-------------------+------+------+------------+-------+
15  * | ff:ff:ff:ff:ff:ff | ff:ff:ff:ff:ff:ff | 8880 | 000a | extraction | frame |
16  * |                   |                   |      |      |   header   |       |
17  * +-------------------+-------------------+------+------+------------+-------+
18  *        48 bits             48 bits      16 bits 16 bits  128 bits
19  *
20  * Extraction with short prefix:
21  *
22  *                                         +------+------+------------+-------+
23  *                                         | 8880 | 000a | extraction | frame |
24  *                                         |      |      |   header   |       |
25  *                                         +------+------+------------+-------+
26  *                                         16 bits 16 bits  128 bits
27  *
28  * Extraction with no prefix:
29  *
30  *                                                       +------------+-------+
31  *                                                       | extraction | frame |
32  *                                                       |   header   |       |
33  *                                                       +------------+-------+
34  *                                                          128 bits
35  *
36  *
37  * Injection with long prefix:
38  *
39  * +-------------------+-------------------+------+------+------------+-------+
40  * |      any dmac     |      any smac     | 8880 | 000a | injection  | frame |
41  * |                   |                   |      |      |   header   |       |
42  * +-------------------+-------------------+------+------+------------+-------+
43  *        48 bits             48 bits      16 bits 16 bits  128 bits
44  *
45  * Injection with short prefix:
46  *
47  *                                         +------+------+------------+-------+
48  *                                         | 8880 | 000a | injection  | frame |
49  *                                         |      |      |   header   |       |
50  *                                         +------+------+------------+-------+
51  *                                         16 bits 16 bits  128 bits
52  *
53  * Injection with no prefix:
54  *
55  *                                                       +------------+-------+
56  *                                                       | injection  | frame |
57  *                                                       |   header   |       |
58  *                                                       +------------+-------+
59  *                                                          128 bits
60  *
61  * The injection header looks like this (network byte order, bit 127
62  * is part of lowest address byte in memory, bit 0 is part of highest
63  * address byte):
64  *
65  *         +------+------+------+------+------+------+------+------+
66  * 127:120 |BYPASS| MASQ |          MASQ_PORT        |REW_OP|REW_OP|
67  *         +------+------+------+------+------+------+------+------+
68  * 119:112 |                         REW_OP                        |
69  *         +------+------+------+------+------+------+------+------+
70  * 111:104 |                         REW_VAL                       |
71  *         +------+------+------+------+------+------+------+------+
72  * 103: 96 |                         REW_VAL                       |
73  *         +------+------+------+------+------+------+------+------+
74  *  95: 88 |                         REW_VAL                       |
75  *         +------+------+------+------+------+------+------+------+
76  *  87: 80 |                         REW_VAL                       |
77  *         +------+------+------+------+------+------+------+------+
78  *  79: 72 |                          RSV                          |
79  *         +------+------+------+------+------+------+------+------+
80  *  71: 64 |            RSV            |           DEST            |
81  *         +------+------+------+------+------+------+------+------+
82  *  63: 56 |                         DEST                          |
83  *         +------+------+------+------+------+------+------+------+
84  *  55: 48 |                          RSV                          |
85  *         +------+------+------+------+------+------+------+------+
86  *  47: 40 |  RSV |         SRC_PORT          |     RSV     |TFRM_TIMER|
87  *         +------+------+------+------+------+------+------+------+
88  *  39: 32 |     TFRM_TIMER     |               RSV                |
89  *         +------+------+------+------+------+------+------+------+
90  *  31: 24 |  RSV |  DP  |   POP_CNT   |           CPUQ            |
91  *         +------+------+------+------+------+------+------+------+
92  *  23: 16 |           CPUQ            |      QOS_CLASS     |TAG_TYPE|
93  *         +------+------+------+------+------+------+------+------+
94  *  15:  8 |         PCP        |  DEI |            VID            |
95  *         +------+------+------+------+------+------+------+------+
96  *   7:  0 |                          VID                          |
97  *         +------+------+------+------+------+------+------+------+
98  *
99  * And the extraction header looks like this:
100  *
101  *         +------+------+------+------+------+------+------+------+
102  * 127:120 |  RSV |                  REW_OP                        |
103  *         +------+------+------+------+------+------+------+------+
104  * 119:112 |       REW_OP       |              REW_VAL             |
105  *         +------+------+------+------+------+------+------+------+
106  * 111:104 |                         REW_VAL                       |
107  *         +------+------+------+------+------+------+------+------+
108  * 103: 96 |                         REW_VAL                       |
109  *         +------+------+------+------+------+------+------+------+
110  *  95: 88 |                         REW_VAL                       |
111  *         +------+------+------+------+------+------+------+------+
112  *  87: 80 |       REW_VAL      |               LLEN               |
113  *         +------+------+------+------+------+------+------+------+
114  *  79: 72 | LLEN |                      WLEN                      |
115  *         +------+------+------+------+------+------+------+------+
116  *  71: 64 | WLEN |                      RSV                       |
117  *         +------+------+------+------+------+------+------+------+
118  *  63: 56 |                          RSV                          |
119  *         +------+------+------+------+------+------+------+------+
120  *  55: 48 |                          RSV                          |
121  *         +------+------+------+------+------+------+------+------+
122  *  47: 40 | RSV  |          SRC_PORT         |       ACL_ID       |
123  *         +------+------+------+------+------+------+------+------+
124  *  39: 32 |       ACL_ID       |  RSV |         SFLOW_ID          |
125  *         +------+------+------+------+------+------+------+------+
126  *  31: 24 |ACL_HIT| DP  |  LRN_FLAGS  |           CPUQ            |
127  *         +------+------+------+------+------+------+------+------+
128  *  23: 16 |           CPUQ            |      QOS_CLASS     |TAG_TYPE|
129  *         +------+------+------+------+------+------+------+------+
130  *  15:  8 |         PCP        |  DEI |            VID            |
131  *         +------+------+------+------+------+------+------+------+
132  *   7:  0 |                          VID                          |
133  *         +------+------+------+------+------+------+------+------+
134  */
135 
136 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
137 				   struct net_device *netdev)
138 {
139 	struct dsa_port *dp = dsa_slave_to_port(netdev);
140 	u64 bypass, dest, src, qos_class, rew_op;
141 	struct dsa_switch *ds = dp->ds;
142 	int port = dp->index;
143 	struct ocelot *ocelot = ds->priv;
144 	struct ocelot_port *ocelot_port = ocelot->ports[port];
145 	u8 *injection;
146 
147 	if (unlikely(skb_cow_head(skb, OCELOT_TAG_LEN) < 0)) {
148 		netdev_err(netdev, "Cannot make room for tag.\n");
149 		return NULL;
150 	}
151 
152 	injection = skb_push(skb, OCELOT_TAG_LEN);
153 
154 	memset(injection, 0, OCELOT_TAG_LEN);
155 
156 	src = dsa_upstream_port(ds, port);
157 	dest = BIT(port);
158 	bypass = true;
159 	qos_class = skb->priority;
160 
161 	packing(injection, &bypass,   127, 127, OCELOT_TAG_LEN, PACK, 0);
162 	packing(injection, &dest,      68,  56, OCELOT_TAG_LEN, PACK, 0);
163 	packing(injection, &src,       46,  43, OCELOT_TAG_LEN, PACK, 0);
164 	packing(injection, &qos_class, 19,  17, OCELOT_TAG_LEN, PACK, 0);
165 
166 	if (ocelot->ptp && (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)) {
167 		rew_op = ocelot_port->ptp_cmd;
168 		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
169 			rew_op |= (ocelot_port->ts_id  % 4) << 3;
170 			ocelot_port->ts_id++;
171 		}
172 
173 		packing(injection, &rew_op, 125, 117, OCELOT_TAG_LEN, PACK, 0);
174 	}
175 
176 	return skb;
177 }
178 
179 static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
180 				  struct net_device *netdev,
181 				  struct packet_type *pt)
182 {
183 	u64 src_port, qos_class;
184 	u8 *start = skb->data;
185 	u8 *extraction;
186 
187 	/* Revert skb->data by the amount consumed by the DSA master,
188 	 * so it points to the beginning of the frame.
189 	 */
190 	skb_push(skb, ETH_HLEN);
191 	/* We don't care about the long prefix, it is just for easy entrance
192 	 * into the DSA master's RX filter. Discard it now by moving it into
193 	 * the headroom.
194 	 */
195 	skb_pull(skb, OCELOT_LONG_PREFIX_LEN);
196 	/* And skb->data now points to the extraction frame header.
197 	 * Keep a pointer to it.
198 	 */
199 	extraction = skb->data;
200 	/* Now the EFH is part of the headroom as well */
201 	skb_pull(skb, OCELOT_TAG_LEN);
202 	/* Reset the pointer to the real MAC header */
203 	skb_reset_mac_header(skb);
204 	skb_reset_mac_len(skb);
205 	/* And move skb->data to the correct location again */
206 	skb_pull(skb, ETH_HLEN);
207 
208 	/* Remove from inet csum the extraction header */
209 	skb_postpull_rcsum(skb, start, OCELOT_LONG_PREFIX_LEN + OCELOT_TAG_LEN);
210 
211 	packing(extraction, &src_port,  46, 43, OCELOT_TAG_LEN, UNPACK, 0);
212 	packing(extraction, &qos_class, 19, 17, OCELOT_TAG_LEN, UNPACK, 0);
213 
214 	skb->dev = dsa_master_find_slave(netdev, 0, src_port);
215 	if (!skb->dev)
216 		/* The switch will reflect back some frames sent through
217 		 * sockets opened on the bare DSA master. These will come back
218 		 * with src_port equal to the index of the CPU port, for which
219 		 * there is no slave registered. So don't print any error
220 		 * message here (ignore and drop those frames).
221 		 */
222 		return NULL;
223 
224 	skb->offload_fwd_mark = 1;
225 	skb->priority = qos_class;
226 
227 	return skb;
228 }
229 
230 static struct dsa_device_ops ocelot_netdev_ops = {
231 	.name			= "ocelot",
232 	.proto			= DSA_TAG_PROTO_OCELOT,
233 	.xmit			= ocelot_xmit,
234 	.rcv			= ocelot_rcv,
235 	.overhead		= OCELOT_TAG_LEN + OCELOT_LONG_PREFIX_LEN,
236 };
237 
238 MODULE_LICENSE("GPL v2");
239 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT);
240 
241 module_dsa_tag_driver(ocelot_netdev_ops);
242