net: dsa: add Renesas RZ/N1 switch tag driver

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@bootlin.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 64da5ed27fdc5702ce72e6cd61b094d55f0848d5..33283eeda697cc1883ff3b24ebfd288d54c33df4 100644 (file)
--- 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/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index 1d0bccc3fa54cd55db9369e0aa26c1ce38918f53..d370165bc621e873568c7c215e9e46b773922b3e 100644 (file)
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -116,6 +116,7 @@
 #define ETH_P_QINQ3    0x9300          /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_EDSA     0xDADA          /* Ethertype DSA [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_DSA_8021Q        0xDADB          /* Fake VLAN Header for DSA [ NOT AN OFFICIALLY REGISTERED ID ] */
+#define ETH_P_DSA_A5PSW        0xE001          /* A5PSW Tag Value [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_IFE      0xED3E          /* ForCES inter-FE LFB type */
 #define ETH_P_AF_IUCV   0xFBFB         /* IBM af_iucv [ NOT AN OFFICIALLY REGISTERED ID ] */
 

diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 8cb87b5067ee2c0659cabbe316058c3432aa0348..63853fff4e2ff14ca86d861588ae5dee315ad613 100644 (file)
--- 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 an 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 9f75820e7c9802bd07c14fd3c327e7f97bc669aa..af28c24ead1854c97f7350e5f1e1f3f4d8e5bbbe 100644 (file)
--- 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 (file)
index 0000000..e2a5ee6
--- /dev/null
+++ b/net/dsa/tag_rzn1_a5psw.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Schneider Electric
+ *
+ * Clément Léger <clement.leger@bootlin.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.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 ETH_P_DSA_A5PSW                        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 60 bytes otherwise they will be discarded when they enter the
+        * switch port logic.
+        */
+       if (__skb_put_padto(skb, ETH_ZLEN, 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(ETH_P_DSA_A5PSW);
+       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(ETH_P_DSA_A5PSW)) {
+               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);