1 files changed, 334 insertions, 0 deletions
diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
new file mode 100644
index 000000000..a65d62fb9
--- /dev/null
+++ b/net/dsa/tag_brcm.c
@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Broadcom tag support
+ *
+ * Copyright (C) 2014 Broadcom Corporation
+ */
+
+#include <linux/dsa/brcm.h>
+#include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include "dsa_priv.h"
+
+/* Legacy Broadcom tag (6 bytes) */
+#define BRCM_LEG_TAG_LEN	6
+
+/* Type fields */
+/* 1st byte in the tag */
+#define BRCM_LEG_TYPE_HI	0x88
+/* 2nd byte in the tag */
+#define BRCM_LEG_TYPE_LO	0x74
+
+/* Tag fields */
+/* 3rd byte in the tag */
+#define BRCM_LEG_UNICAST	(0 << 5)
+#define BRCM_LEG_MULTICAST	(1 << 5)
+#define BRCM_LEG_EGRESS		(2 << 5)
+#define BRCM_LEG_INGRESS	(3 << 5)
+
+/* 6th byte in the tag */
+#define BRCM_LEG_PORT_ID	(0xf)
+
+/* Newer Broadcom tag (4 bytes) */
+#define BRCM_TAG_LEN	4
+
+/* Tag is constructed and deconstructed using byte by byte access
+ * because the tag is placed after the MAC Source Address, which does
+ * not make it 4-bytes aligned, so this might cause unaligned accesses
+ * on most systems where this is used.
+ */
+
+/* Ingress and egress opcodes */
+#define BRCM_OPCODE_SHIFT	5
+#define BRCM_OPCODE_MASK	0x7
+
+/* Ingress fields */
+/* 1st byte in the tag */
+#define BRCM_IG_TC_SHIFT	2
+#define BRCM_IG_TC_MASK		0x7
+/* 2nd byte in the tag */
+#define BRCM_IG_TE_MASK		0x3
+#define BRCM_IG_TS_SHIFT	7
+/* 3rd byte in the tag */
+#define BRCM_IG_DSTMAP2_MASK	1
+#define BRCM_IG_DSTMAP1_MASK	0xff
+
+/* Egress fields */
+
+/* 2nd byte in the tag */
+#define BRCM_EG_CID_MASK	0xff
+
+/* 3rd byte in the tag */
+#define BRCM_EG_RC_MASK		0xff
+#define  BRCM_EG_RC_RSVD	(3 << 6)
+#define  BRCM_EG_RC_EXCEPTION	(1 << 5)
+#define  BRCM_EG_RC_PROT_SNOOP	(1 << 4)
+#define  BRCM_EG_RC_PROT_TERM	(1 << 3)
+#define  BRCM_EG_RC_SWITCH	(1 << 2)
+#define  BRCM_EG_RC_MAC_LEARN	(1 << 1)
+#define  BRCM_EG_RC_MIRROR	(1 << 0)
+#define BRCM_EG_TC_SHIFT	5
+#define BRCM_EG_TC_MASK		0x7
+#define BRCM_EG_PID_MASK	0x1f
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM) || \
+	IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
+
+static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
+					struct net_device *dev,
+					unsigned int offset)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	u16 queue = skb_get_queue_mapping(skb);
+	u8 *brcm_tag;
+
+	/* The Ethernet switch we are interfaced with needs packets to be at
+	 * least 64 bytes (including FCS) otherwise they will be discarded when
+	 * they enter the switch port logic. When Broadcom tags are enabled, we
+	 * need to make sure that packets are at least 68 bytes
+	 * (including FCS and tag) because the length verification is done after
+	 * the Broadcom tag is stripped off the ingress packet.
+	 *
+	 * Let dsa_slave_xmit() free the SKB
+	 */
+	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
+		return NULL;
+
+	skb_push(skb, BRCM_TAG_LEN);
+
+	if (offset)
+		dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
+
+	brcm_tag = skb->data + offset;
+
+	/* Set the ingress opcode, traffic class, tag enforcement is
+	 * deprecated
+	 */
+	brcm_tag[0] = (1 << BRCM_OPCODE_SHIFT) |
+		       ((queue & BRCM_IG_TC_MASK) << BRCM_IG_TC_SHIFT);
+	brcm_tag[1] = 0;
+	brcm_tag[2] = 0;
+	if (dp->index == 8)
+		brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
+	brcm_tag[3] = (1 << dp->index) & BRCM_IG_DSTMAP1_MASK;
+
+	/* Now tell the master network device about the desired output queue
+	 * as well
+	 */
+	skb_set_queue_mapping(skb, BRCM_TAG_SET_PORT_QUEUE(dp->index, queue));
+
+	return skb;
+}
+
+/* Frames with this tag have one of these two layouts:
+ * -----------------------------------
+ * | MAC DA | MAC SA | 4b tag | Type | DSA_TAG_PROTO_BRCM
+ * -----------------------------------
+ * -----------------------------------
+ * | 4b tag | MAC DA | MAC SA | Type | DSA_TAG_PROTO_BRCM_PREPEND
+ * -----------------------------------
+ * In both cases, at receive time, skb->data points 2 bytes before the actual
+ * Ethernet type field and we have an offset of 4bytes between where skb->data
+ * and where the payload starts. So the same low-level receive function can be
+ * used.
+ */
+static struct sk_buff *brcm_tag_rcv_ll(struct sk_buff *skb,
+				       struct net_device *dev,
+				       unsigned int offset)
+{
+	int source_port;
+	u8 *brcm_tag;
+
+	if (unlikely(!pskb_may_pull(skb, BRCM_TAG_LEN)))
+		return NULL;
+
+	brcm_tag = skb->data - offset;
+
+	/* The opcode should never be different than 0b000 */
+	if (unlikely((brcm_tag[0] >> BRCM_OPCODE_SHIFT) & BRCM_OPCODE_MASK))
+		return NULL;
+
+	/* We should never see a reserved reason code without knowing how to
+	 * handle it
+	 */
+	if (unlikely(brcm_tag[2] & BRCM_EG_RC_RSVD))
+		return NULL;
+
+	/* Locate which port this is coming from */
+	source_port = brcm_tag[3] & BRCM_EG_PID_MASK;
+
+	skb->dev = dsa_master_find_slave(dev, 0, source_port);
+	if (!skb->dev)
+		return NULL;
+
+	/* Remove Broadcom tag and update checksum */
+	skb_pull_rcsum(skb, BRCM_TAG_LEN);
+
+	dsa_default_offload_fwd_mark(skb);
+
+	return skb;
+}
+#endif
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
+static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb,
+				     struct net_device *dev)
+{
+	/* Build the tag after the MAC Source Address */
+	return brcm_tag_xmit_ll(skb, dev, 2 * ETH_ALEN);
+}
+
+
+static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
+{
+	struct sk_buff *nskb;
+
+	/* skb->data points to the EtherType, the tag is right before it */
+	nskb = brcm_tag_rcv_ll(skb, dev, 2);
+	if (!nskb)
+		return nskb;
+
+	dsa_strip_etype_header(skb, BRCM_TAG_LEN);
+
+	return nskb;
+}
+
+static const struct dsa_device_ops brcm_netdev_ops = {
+	.name	= "brcm",
+	.proto	= DSA_TAG_PROTO_BRCM,
+	.xmit	= brcm_tag_xmit,
+	.rcv	= brcm_tag_rcv,
+	.needed_headroom = BRCM_TAG_LEN,
+};
+
+DSA_TAG_DRIVER(brcm_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
+#endif
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
+static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
+					 struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	u8 *brcm_tag;
+
+	/* The Ethernet switch we are interfaced with needs packets to be at
+	 * least 64 bytes (including FCS) otherwise they will be discarded when
+	 * they enter the switch port logic. When Broadcom tags are enabled, we
+	 * need to make sure that packets are at least 70 bytes
+	 * (including FCS and tag) because the length verification is done after
+	 * the Broadcom tag is stripped off the ingress packet.
+	 *
+	 * Let dsa_slave_xmit() free the SKB
+	 */
+	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false))
+		return NULL;
+
+	skb_push(skb, BRCM_LEG_TAG_LEN);
+
+	dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
+
+	brcm_tag = skb->data + 2 * ETH_ALEN;
+
+	/* Broadcom tag type */
+	brcm_tag[0] = BRCM_LEG_TYPE_HI;
+	brcm_tag[1] = BRCM_LEG_TYPE_LO;
+
+	/* Broadcom tag value */
+	brcm_tag[2] = BRCM_LEG_EGRESS;
+	brcm_tag[3] = 0;
+	brcm_tag[4] = 0;
+	brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
+
+	return skb;
+}
+
+static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	int len = BRCM_LEG_TAG_LEN;
+	int source_port;
+	u8 *brcm_tag;
+
+	if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
+		return NULL;
+
+	brcm_tag = dsa_etype_header_pos_rx(skb);
+
+	source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
+
+	skb->dev = dsa_master_find_slave(dev, 0, source_port);
+	if (!skb->dev)
+		return NULL;
+
+	/* VLAN tag is added by BCM63xx internal switch */
+	if (netdev_uses_dsa(skb->dev))
+		len += VLAN_HLEN;
+
+	/* Remove Broadcom tag and update checksum */
+	skb_pull_rcsum(skb, len);
+
+	dsa_default_offload_fwd_mark(skb);
+
+	dsa_strip_etype_header(skb, len);
+
+	return skb;
+}
+
+static const struct dsa_device_ops brcm_legacy_netdev_ops = {
+	.name = "brcm-legacy",
+	.proto = DSA_TAG_PROTO_BRCM_LEGACY,
+	.xmit = brcm_leg_tag_xmit,
+	.rcv = brcm_leg_tag_rcv,
+	.needed_headroom = BRCM_LEG_TAG_LEN,
+};
+
+DSA_TAG_DRIVER(brcm_legacy_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY);
+#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
+static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb,
+					     struct net_device *dev)
+{
+	/* tag is prepended to the packet */
+	return brcm_tag_xmit_ll(skb, dev, 0);
+}
+
+static struct sk_buff *brcm_tag_rcv_prepend(struct sk_buff *skb,
+					    struct net_device *dev)
+{
+	/* tag is prepended to the packet */
+	return brcm_tag_rcv_ll(skb, dev, ETH_HLEN);
+}
+
+static const struct dsa_device_ops brcm_prepend_netdev_ops = {
+	.name	= "brcm-prepend",
+	.proto	= DSA_TAG_PROTO_BRCM_PREPEND,
+	.xmit	= brcm_tag_xmit_prepend,
+	.rcv	= brcm_tag_rcv_prepend,
+	.needed_headroom = BRCM_TAG_LEN,
+};
+
+DSA_TAG_DRIVER(brcm_prepend_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_PREPEND);
+#endif
+
+static struct dsa_tag_driver *dsa_tag_driver_array[] =	{
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
+	&DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY)
+	&DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops),
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND)
+	&DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops),
+#endif
+};
+
+module_dsa_tag_drivers(dsa_tag_driver_array);
+
+MODULE_LICENSE("GPL");