tag_brcm.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Broadcom tag support
  4 *
  5 * Copyright (C) 2014 Broadcom Corporation
  6 */
  7
  8#include <linux/dsa/brcm.h>
  9#include <linux/etherdevice.h>
 10#include <linux/if_vlan.h>
 11#include <linux/list.h>
 12#include <linux/slab.h>
 13
 14#include "tag.h"
 15
 16#define BRCM_NAME		"brcm"
 17#define BRCM_LEGACY_NAME	"brcm-legacy"
 18#define BRCM_LEGACY_FCS_NAME	"brcm-legacy-fcs"
 19#define BRCM_PREPEND_NAME	"brcm-prepend"
 20
 21/* Legacy Broadcom tag (6 bytes) */
 22#define BRCM_LEG_TAG_LEN	6
 23
 24/* Type fields */
 25/* 1st byte in the tag */
 26#define BRCM_LEG_TYPE_HI	0x88
 27/* 2nd byte in the tag */
 28#define BRCM_LEG_TYPE_LO	0x74
 29
 30/* Tag fields */
 31/* 3rd byte in the tag */
 32#define BRCM_LEG_UNICAST	(0 << 5)
 33#define BRCM_LEG_MULTICAST	(1 << 5)
 34#define BRCM_LEG_EGRESS		(2 << 5)
 35#define BRCM_LEG_INGRESS	(3 << 5)
 36#define BRCM_LEG_LEN_HI(x)	(((x) >> 8) & 0x7)
 37
 38/* 4th byte in the tag */
 39#define BRCM_LEG_LEN_LO(x)	((x) & 0xff)
 40
 41/* 6th byte in the tag */
 42#define BRCM_LEG_PORT_ID	(0xf)
 43
 44/* Newer Broadcom tag (4 bytes) */
 45#define BRCM_TAG_LEN	4
 46
 47/* Tag is constructed and deconstructed using byte by byte access
 48 * because the tag is placed after the MAC Source Address, which does
 49 * not make it 4-bytes aligned, so this might cause unaligned accesses
 50 * on most systems where this is used.
 51 */
 52
 53/* Ingress and egress opcodes */
 54#define BRCM_OPCODE_SHIFT	5
 55#define BRCM_OPCODE_MASK	0x7
 56
 57/* Ingress fields */
 58/* 1st byte in the tag */
 59#define BRCM_IG_TC_SHIFT	2
 60#define BRCM_IG_TC_MASK		0x7
 61/* 2nd byte in the tag */
 62#define BRCM_IG_TE_MASK		0x3
 63#define BRCM_IG_TS_SHIFT	7
 64/* 3rd byte in the tag */
 65#define BRCM_IG_DSTMAP2_MASK	1
 66#define BRCM_IG_DSTMAP1_MASK	0xff
 67
 68/* Egress fields */
 69
 70/* 2nd byte in the tag */
 71#define BRCM_EG_CID_MASK	0xff
 72
 73/* 3rd byte in the tag */
 74#define BRCM_EG_RC_MASK		0xff
 75#define  BRCM_EG_RC_RSVD	(3 << 6)
 76#define  BRCM_EG_RC_EXCEPTION	(1 << 5)
 77#define  BRCM_EG_RC_PROT_SNOOP	(1 << 4)
 78#define  BRCM_EG_RC_PROT_TERM	(1 << 3)
 79#define  BRCM_EG_RC_SWITCH	(1 << 2)
 80#define  BRCM_EG_RC_MAC_LEARN	(1 << 1)
 81#define  BRCM_EG_RC_MIRROR	(1 << 0)
 82#define BRCM_EG_TC_SHIFT	5
 83#define BRCM_EG_TC_MASK		0x7
 84#define BRCM_EG_PID_MASK	0x1f
 85
 86#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
 87	IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
 88
 89static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
 90					struct net_device *dev,
 91					unsigned int offset)
 92{
 93	struct dsa_port *dp = dsa_user_to_port(dev);
 94	u16 queue = skb_get_queue_mapping(skb);
 95	u16 port_mask;
 96	u8 *brcm_tag;
 97
 98	/* The Ethernet switch we are interfaced with needs packets to be at
 99	 * least 64 bytes (including FCS) otherwise they will be discarded when
100	 * they enter the switch port logic. When Broadcom tags are enabled, we
101	 * need to make sure that packets are at least 68 bytes
102	 * (including FCS and tag) because the length verification is done after
103	 * the Broadcom tag is stripped off the ingress packet.
104	 *
105	 * Let dsa_user_xmit() free the SKB
106	 */
107	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
108		return NULL;
109
110	skb_push(skb, BRCM_TAG_LEN);
111
112	if (offset)
113		dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
114
115	brcm_tag = skb->data + offset;
116
117	/* Set the ingress opcode, traffic class, tag enforcement is
118	 * deprecated
119	 */
120	brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
121		       ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
122	brcm_tag[1] = 0;
123	port_mask = dsa_xmit_port_mask(skb, dev);
124	brcm_tag[2] = (port_mask >> 8) & BRCM_IG_DSTMAP2_MASK;
125	brcm_tag[3] = port_mask & BRCM_IG_DSTMAP1_MASK;
126
127	/* Now tell the conduit network device about the desired output queue
128	 * as well
129	 */
130	skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
131
132	return skb;
133}
134
135/* Frames with this tag have one of these two layouts:
136 * -----------------------------------
137 * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
138 * -----------------------------------
139 * -----------------------------------
140 * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
141 * -----------------------------------
142 * In both cases, at receive time, skb->data points 2 bytes before the actual
143 * Ethernet type field and we have an offset of 4bytes between where skb->data
144 * and where the payload starts. So the same low-level receive function can be
145 * used.
146 */
147static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
148				       struct net_device *dev,
149				       unsigned int offset)
150{
151	int source_port;
152	u8 *brcm_tag;
153
154	if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
155		return NULL;
156
157	brcm_tag = skb->data - offset;
158
159	/* The opcode should never be different than 0b000 */
160	if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
161		return NULL;
162
163	/* We should never see a reserved reason code without knowing how to
164	 * handle it
165	 */
166	if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
167		return NULL;
168
169	/* Locate which port this is coming from */
170	source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
171
172	skb->dev = dsa_conduit_find_user(dev, 0, source_port);
173	if (!skb->dev)
174		return NULL;
175
176	/* Remove Broadcom tag and update checksum */
177	skb_pull_rcsum(skb, BRCM_TAG_LEN);
178
179	if (likely(!is_link_local_ether_addr(eth_hdr(skb)->h_dest)))
180		dsa_default_offload_fwd_mark(skb);
181
182	return skb;
183}
184#endif
185
186#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
187static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
188				     struct net_device *dev)
189{
190	/* Build the tag after the MAC Source Address */
191	return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
192}
193
194
195static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
196{
197	struct sk_buff *nskb;
198
199	/* skb->data points to the EtherType, the tag is right before it */
200	nskb = brcm_tag_rcv_ll(skb, dev, 2);
201	if (!nskb)
202		return nskb;
203
204	dsa_strip_etype_header(skb, BRCM_TAG_LEN);
205
206	return nskb;
207}
208
209static const struct dsa_device_ops brcm_netdev_ops = {
210	.name	= BRCM_NAME,
211	.proto	= DSA_TAG_PROTO_BRCM,
212	.xmit	= brcm_tag_xmit,
213	.rcv	= brcm_tag_rcv,
214	.needed_headroom = BRCM_TAG_LEN,
215};
216
217DSA_TAG_DRIVER(brcm_netdev_ops);
218MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM, BRCM_NAME);
219#endif
220
221#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) || \
222	IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
223static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
224					struct net_device *dev)
225{
226	int len = BRCM_LEG_TAG_LEN;
227	int source_port;
228	__be16 *proto;
229	u8 *brcm_tag;
230
231	if (unlikely(!pskb_may_pull(skb, BRCM_LEG_TAG_LEN + VLAN_HLEN)))
232		return NULL;
233
234	brcm_tag = dsa_etype_header_pos_rx(skb);
235	proto = (__be16 *)(brcm_tag + BRCM_LEG_TAG_LEN);
236
237	source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
238
239	skb->dev = dsa_conduit_find_user(dev, 0, source_port);
240	if (!skb->dev)
241		return NULL;
242
243	/* The internal switch in BCM63XX SoCs always tags on egress on the CPU
244	 * port. We use VID 0 internally for untagged traffic, so strip the tag
245	 * if the TCI field is all 0, and keep it otherwise to also retain
246	 * e.g. 802.1p tagged packets.
247	 */
248	if (proto[0] == htons(ETH_P_8021Q) && proto[1] == 0)
249		len += VLAN_HLEN;
250
251	/* Remove Broadcom tag and update checksum */
252	skb_pull_rcsum(skb, len);
253
254	if (likely(!is_link_local_ether_addr(eth_hdr(skb)->h_dest)))
255		dsa_default_offload_fwd_mark(skb);
256
257	dsa_strip_etype_header(skb, len);
258
259	return skb;
260}
261#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY || CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */
262
263#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
264static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
265					 struct net_device *dev)
266{
267	struct dsa_port *dp = dsa_user_to_port(dev);
268	u8 *brcm_tag;
269
270	/* The Ethernet switch we are interfaced with needs packets to be at
271	 * least 64 bytes (including FCS) otherwise they will be discarded when
272	 * they enter the switch port logic. When Broadcom tags are enabled, we
273	 * need to make sure that packets are at least 70 bytes
274	 * (including FCS and tag) because the length verification is done after
275	 * the Broadcom tag is stripped off the ingress packet.
276	 *
277	 * Let dsa_user_xmit() free the SKB
278	 */
279	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
280		return NULL;
281
282	skb_push(skb, BRCM_LEG_TAG_LEN);
283
284	dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
285
286	brcm_tag = skb->data + 2 * ETH_ALEN;
287
288	/* Broadcom tag type */
289	brcm_tag[0] = BRCM_LEG_TYPE_HI;
290	brcm_tag[1] = BRCM_LEG_TYPE_LO;
291
292	/* Broadcom tag value */
293	brcm_tag[2] = BRCM_LEG_EGRESS;
294	brcm_tag[3] = 0;
295	brcm_tag[4] = 0;
296	brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
297
298	return skb;
299}
300
301static const struct dsa_device_ops brcm_legacy_netdev_ops = {
302	.name = BRCM_LEGACY_NAME,
303	.proto = DSA_TAG_PROTO_BRCM_LEGACY,
304	.xmit = brcm_leg_tag_xmit,
305	.rcv = brcm_leg_tag_rcv,
306	.needed_headroom = BRCM_LEG_TAG_LEN,
307};
308
309DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
310MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY, BRCM_LEGACY_NAME);
311#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
312
313#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
314static struct sk_buff *brcm_leg_fcs_tag_xmit(struct sk_buff *skb,
315					     struct net_device *dev)
316{
317	struct dsa_port *dp = dsa_user_to_port(dev);
318	unsigned int fcs_len;
319	__le32 fcs_val;
320	u8 *brcm_tag;
321
322	/* The Ethernet switch we are interfaced with needs packets to be at
323	 * least 64 bytes (including FCS) otherwise they will be discarded when
324	 * they enter the switch port logic. When Broadcom tags are enabled, we
325	 * need to make sure that packets are at least 70 bytes (including FCS
326	 * and tag) because the length verification is done after the Broadcom
327	 * tag is stripped off the ingress packet.
328	 *
329	 * Let dsa_user_xmit() free the SKB.
330	 */
331	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
332		return NULL;
333
334	fcs_len = skb->len;
335	fcs_val = cpu_to_le32(crc32_le(~0, skb->data, fcs_len) ^ ~0);
336
337	skb_push(skb, BRCM_LEG_TAG_LEN);
338
339	dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
340
341	brcm_tag = skb->data + 2 * ETH_ALEN;
342
343	/* Broadcom tag type */
344	brcm_tag[0] = BRCM_LEG_TYPE_HI;
345	brcm_tag[1] = BRCM_LEG_TYPE_LO;
346
347	/* Broadcom tag value */
348	brcm_tag[2] = BRCM_LEG_EGRESS | BRCM_LEG_LEN_HI(fcs_len);
349	brcm_tag[3] = BRCM_LEG_LEN_LO(fcs_len);
350	brcm_tag[4] = 0;
351	brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
352
353	/* Original FCS value */
354	if (__skb_pad(skb, ETH_FCS_LEN, false))
355		return NULL;
356	skb_put_data(skb, &fcs_val, ETH_FCS_LEN);
357
358	return skb;
359}
360
361static const struct dsa_device_ops brcm_legacy_fcs_netdev_ops = {
362	.name = BRCM_LEGACY_FCS_NAME,
363	.proto = DSA_TAG_PROTO_BRCM_LEGACY_FCS,
364	.xmit = brcm_leg_fcs_tag_xmit,
365	.rcv = brcm_leg_tag_rcv,
366	.needed_headroom = BRCM_LEG_TAG_LEN,
367};
368
369DSA_TAG_DRIVER(brcm_legacy_fcs_netdev_ops);
370MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY_FCS, BRCM_LEGACY_FCS_NAME);
371#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */
372
373#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
374static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
375					     struct net_device *dev)
376{
377	/* tag is prepended to the packet */
378	return brcm_tag_xmit_ll(skb, dev, 0);
379}
380
381static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
382					    struct net_device *dev)
383{
384	/* tag is prepended to the packet */
385	return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
386}
387
388static const struct dsa_device_ops brcm_prepend_netdev_ops = {
389	.name	= BRCM_PREPEND_NAME,
390	.proto	= DSA_TAG_PROTO_BRCM_PREPEND,
391	.xmit	= brcm_tag_xmit_prepend,
392	.rcv	= brcm_tag_rcv_prepend,
393	.needed_headroom = BRCM_TAG_LEN,
394};
395
396DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
397MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND, BRCM_PREPEND_NAME);
398#endif
399
400static struct dsa_tag_driver *dsa_tag_driver_array[] =	{
401#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
402	&DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
403#endif
404#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
405	&DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
406#endif
407#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS)
408	&DSA_TAG_DRIVER_NAME(brcm_legacy_fcs_netdev_ops),
409#endif
410#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
411	&DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
412#endif
413};
414
415module_dsa_tag_drivers(dsa_tag_driver_array);
416
417MODULE_DESCRIPTION("DSA tag driver for Broadcom switches using in-frame headers");
418MODULE_LICENSE("GPL");