net: dsa: tag_brcm: add support for legacy tags

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>

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 83a933e..dac303e 100644 (file)
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -49,10 +49,12 @@ struct phylink_link_state;
 #define DSA_TAG_PROTO_XRS700X_VALUE            19
 #define DSA_TAG_PROTO_OCELOT_8021Q_VALUE       20
 #define DSA_TAG_PROTO_SEVILLE_VALUE            21
+#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,

diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 58b8fc8..aaf8a45 100644 (file)
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -48,6 +48,13 @@ 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"

diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index e2577a7..40e9f30 100644 (file)
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -12,9 +12,26 @@
 
 #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
@@ -195,6 +212,87 @@ 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)
@@ -227,6 +325,9 @@ 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