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From 964dbf186eaa84d409c359ddf09c827a3fbe8228 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Wed, 17 Mar 2021 11:29:26 +0100
Subject: [PATCH 1/2] net: dsa: tag_brcm: add support for legacy tags
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Add support for legacy Broadcom tags, which are similar to DSA_TAG_PROTO_BRCM.
These tags are used on BCM5325, BCM5365 and BCM63xx switches.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/dsa.h | 2 +
net/dsa/Kconfig | 7 +++
net/dsa/tag_brcm.c | 107 +++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 113 insertions(+), 3 deletions(-)
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -45,10 +45,12 @@ struct phylink_link_state;
#define DSA_TAG_PROTO_OCELOT_VALUE 15
#define DSA_TAG_PROTO_AR9331_VALUE 16
#define DSA_TAG_PROTO_RTL4_A_VALUE 17
+#define DSA_TAG_PROTO_BRCM_LEGACY_VALUE 22
enum dsa_tag_protocol {
DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
DSA_TAG_PROTO_BRCM = DSA_TAG_PROTO_BRCM_VALUE,
+ DSA_TAG_PROTO_BRCM_LEGACY = DSA_TAG_PROTO_BRCM_LEGACY_VALUE,
DSA_TAG_PROTO_BRCM_PREPEND = DSA_TAG_PROTO_BRCM_PREPEND_VALUE,
DSA_TAG_PROTO_DSA = DSA_TAG_PROTO_DSA_VALUE,
DSA_TAG_PROTO_EDSA = DSA_TAG_PROTO_EDSA_VALUE,
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -47,6 +47,13 @@ config NET_DSA_TAG_BRCM
Say Y if you want to enable support for tagging frames for the
Broadcom switches which place the tag after the MAC source address.
+config NET_DSA_TAG_BRCM_LEGACY
+ tristate "Tag driver for Broadcom legacy switches using in-frame headers"
+ select NET_DSA_TAG_BRCM_COMMON
+ help
+ Say Y if you want to enable support for tagging frames for the
+ Broadcom legacy switches which place the tag after the MAC source
+ address.
config NET_DSA_TAG_BRCM_PREPEND
tristate "Tag driver for Broadcom switches using prepended headers"
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -11,9 +11,26 @@
#include "dsa_priv.h"
-/* This tag length is 4 bytes, older ones were 6 bytes, we do not
- * handle them
- */
+/* 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 desconstructed using byte by byte access
@@ -194,6 +211,87 @@ 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);
+
+ memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN);
+
+ 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,
+ struct packet_type *pt)
+{
+ int source_port;
+ u8 *brcm_tag;
+
+ if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
+ return NULL;
+
+ brcm_tag = skb->data - 2;
+
+ source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
+
+ 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_LEG_TAG_LEN);
+
+ skb->offload_fwd_mark = 1;
+
+ /* Move the Ethernet DA and SA */
+ memmove(skb->data - ETH_HLEN,
+ skb->data - ETH_HLEN - BRCM_LEG_TAG_LEN,
+ 2 * ETH_ALEN);
+
+ 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,
+ .overhead = 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)
@@ -226,6 +324,9 @@ static struct dsa_tag_driver *dsa_tag_dr
#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
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