The switch that is present on the Renesas RZ/N1 SoC uses a specific
VLAN value followed by 6 bytes which contains forwarding configuration.
Signed-off-by: Clément Léger <clement.leger@xxxxxxxxxxx>
---
include/net/dsa.h | 2 +
net/dsa/Kconfig | 7 +++
net/dsa/Makefile | 1 +
net/dsa/tag_rzn1_a5psw.c | 114 +++++++++++++++++++++++++++++++++++++++
4 files changed, 124 insertions(+)
create mode 100644 net/dsa/tag_rzn1_a5psw.c
diff --git a/include/net/dsa.h b/include/net/dsa.h
index d9da32aacbf1..9aaaa7deb102 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -53,6 +53,7 @@ struct phylink_link_state;
#define DSA_TAG_PROTO_SJA1110_VALUE 23
#define DSA_TAG_PROTO_RTL8_4_VALUE 24
#define DSA_TAG_PROTO_RTL8_4T_VALUE 25
+#define DSA_TAG_PROTO_RZN1_A5PSW_VALUE 26
enum dsa_tag_protocol {
DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
@@ -81,6 +82,7 @@ enum dsa_tag_protocol {
DSA_TAG_PROTO_SJA1110 = DSA_TAG_PROTO_SJA1110_VALUE,
DSA_TAG_PROTO_RTL8_4 = DSA_TAG_PROTO_RTL8_4_VALUE,
DSA_TAG_PROTO_RTL8_4T = DSA_TAG_PROTO_RTL8_4T_VALUE,
+ DSA_TAG_PROTO_RZN1_A5PSW = DSA_TAG_PROTO_RZN1_A5PSW_VALUE,
};
struct dsa_switch;
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 8cb87b5067ee..e22f33d7cf60 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -132,6 +132,13 @@ config NET_DSA_TAG_RTL8_4
Say Y or M if you want to enable support for tagging frames for Realtek
switches with 8 byte protocol 4 tags, such as the Realtek RTL8365MB-VC.
+config NET_DSA_TAG_RZN1_A5PSW
+ tristate "Tag driver for Renesas RZ/N1 A5PSW switch"
+ help
+ Say Y or M if you want to enable support for tagging frames for
+ Renesas RZ/N1 embedded switch that uses a 8 byte tag located after
+ destination MAC address.
+
config NET_DSA_TAG_LAN9303
tristate "Tag driver for SMSC/Microchip LAN9303 family of switches"
help
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 9f75820e7c98..af28c24ead18 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o
obj-$(CONFIG_NET_DSA_TAG_RTL8_4) += tag_rtl8_4.o
+obj-$(CONFIG_NET_DSA_TAG_RZN1_A5PSW) += tag_rzn1_a5psw.o
obj-$(CONFIG_NET_DSA_TAG_SJA1105) += tag_sja1105.o
obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
obj-$(CONFIG_NET_DSA_TAG_XRS700X) += tag_xrs700x.o
diff --git a/net/dsa/tag_rzn1_a5psw.c b/net/dsa/tag_rzn1_a5psw.c
new file mode 100644
index 000000000000..87177682eb54
--- /dev/null
+++ b/net/dsa/tag_rzn1_a5psw.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Schneider Electric
+ *
+ * Clément Léger <clement.leger@xxxxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/etherdevice.h>
+#include <net/dsa.h>
+
+#include "dsa_priv.h"
+
+/* To define the outgoing port and to discover the incoming port a TAG is
+ * inserted after Src MAC :
+ *
+ * Dest MAC Src MAC TAG Type
+ * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 5 6 7 8 | 1 2 |...
+ * |<--------------->|
+ *
+ * See struct a5psw_tag for layout
+ */
+
+#define A5PSW_TAG_VALUE 0xE001
+#define A5PSW_TAG_LEN 8
+#define A5PSW_CTRL_DATA_FORCE_FORWARD BIT(0)
+/* This is both used for xmit tag and rcv tagging */
+#define A5PSW_CTRL_DATA_PORT GENMASK(3, 0)
+
+struct a5psw_tag {
+ __be16 ctrl_tag;
+ __be16 ctrl_data;
+ __be16 ctrl_data2_hi;
+ __be16 ctrl_data2_lo;
+};
+
+static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct dsa_port *dp = dsa_slave_to_port(dev);
+ struct a5psw_tag *ptag;
+ u32 data2_val;
+
+ BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN);
+
+ /* 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 tagging is enabled, we need
+ * to make sure that packets are at least 70 bytes (including FCS and
+ * tag).
+ */
+ if (__skb_put_padto(skb, ETH_ZLEN + ETH_FCS_LEN + A5PSW_TAG_LEN, false))
+ return NULL;
+
+ /* provide 'A5PSW_TAG_LEN' bytes additional space */
+ skb_push(skb, A5PSW_TAG_LEN);
+
+ /* make room between MACs and Ether-Type to insert tag */
+ dsa_alloc_etype_header(skb, A5PSW_TAG_LEN);
+
+ ptag = dsa_etype_header_pos_tx(skb);
+
+ data2_val = FIELD_PREP(A5PSW_CTRL_DATA_PORT, BIT(dp->index));
+ ptag->ctrl_tag = htons(A5PSW_TAG_VALUE);
+ ptag->ctrl_data = htons(A5PSW_CTRL_DATA_FORCE_FORWARD);
+ ptag->ctrl_data2_lo = htons(data2_val);
+ ptag->ctrl_data2_hi = 0;
+
+ return skb;
+}
+
+static struct sk_buff *a5psw_tag_rcv(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ struct a5psw_tag *tag;
+ int port;
+
+ if (unlikely(!pskb_may_pull(skb, A5PSW_TAG_LEN))) {
+ dev_warn_ratelimited(&dev->dev,
+ "Dropping packet, cannot pull\n");
+ return NULL;
+ }
+
+ tag = dsa_etype_header_pos_rx(skb);
+
+ if (tag->ctrl_tag != htons(A5PSW_TAG_VALUE)) {
+ dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid TAG marker\n");
+ return NULL;
+ }
+
+ port = FIELD_GET(A5PSW_CTRL_DATA_PORT, ntohs(tag->ctrl_data));
+
+ skb->dev = dsa_master_find_slave(dev, 0, port);
+ if (!skb->dev)
+ return NULL;
+
+ skb_pull_rcsum(skb, A5PSW_TAG_LEN);
+ dsa_strip_etype_header(skb, A5PSW_TAG_LEN);
+
+ dsa_default_offload_fwd_mark(skb);
+
+ return skb;
+}
+
+static const struct dsa_device_ops a5psw_netdev_ops = {
+ .name = "a5psw",
+ .proto = DSA_TAG_PROTO_RZN1_A5PSW,
+ .xmit = a5psw_tag_xmit,
+ .rcv = a5psw_tag_rcv,
+ .needed_headroom = A5PSW_TAG_LEN,
+};
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_A5PSW);
+module_dsa_tag_driver(a5psw_netdev_ops);
--
2.34.1
