[net-next PATCH v18 4/8] net: dsa: tag_mtk: add Airoha variant usage of this TAG

Christian Marangi
2025-09-15T10:46:06Z

Add variant of the MTK TAG for Airoha Switch and comments about difference
between Airoha AN8855 and Mediatek tag bitmap.

Airoha AN8855 doesn't support controlling SA learning and Leaky VLAN
from tag. Although these bits are not used (and even not defined for
Leaky VLAN), it's worth to add comments for these difference to prevent
any kind of regression in the future if ever these bits will be used.

Rework the makefile, config and tag driver to better report to
external tool (like libpcap) the usage of this variant with a dedicated
"Airoha" name.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
include/net/dsa.h | 2 ++
net/dsa/Kconfig | 11 +++++++++++
net/dsa/Makefile | 2 +-
net/dsa/tag_mtk.c | 36 +++++++++++++++++++++++++++++++++---
4 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index d73ea0880066..bf03493e64ab 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -55,6 +55,7 @@ struct tc_action;
#define DSA_TAG_PROTO_LAN937X_VALUE 27
#define DSA_TAG_PROTO_VSC73XX_8021Q_VALUE 28
#define DSA_TAG_PROTO_BRCM_LEGACY_FCS_VALUE 29
+#define DSA_TAG_PROTO_AIROHA_VALUE 30

enum dsa_tag_protocol {
DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
@@ -69,6 +70,7 @@ enum dsa_tag_protocol {
DSA_TAG_PROTO_KSZ9893 = DSA_TAG_PROTO_KSZ9893_VALUE,
DSA_TAG_PROTO_LAN9303 = DSA_TAG_PROTO_LAN9303_VALUE,
DSA_TAG_PROTO_MTK = DSA_TAG_PROTO_MTK_VALUE,
+ DSA_TAG_PROTO_AIROHA = DSA_TAG_PROTO_AIROHA_VALUE,
DSA_TAG_PROTO_QCA = DSA_TAG_PROTO_QCA_VALUE,
DSA_TAG_PROTO_TRAILER = DSA_TAG_PROTO_TRAILER_VALUE,
DSA_TAG_PROTO_8021Q = DSA_TAG_PROTO_8021Q_VALUE,
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 869cbe57162f..7d63ecda25c8 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -98,12 +98,23 @@ config NET_DSA_TAG_EDSA
Say Y or M if you want to enable support for tagging frames for the
Marvell switches which use EtherType DSA headers.

+config NET_DSA_TAG_MTK_COMMON
+ tristate
+
config NET_DSA_TAG_MTK
tristate "Tag driver for Mediatek switches"
+ select NET_DSA_TAG_MTK_COMMON
help
Say Y or M if you want to enable support for tagging frames for
Mediatek switches.

+config NET_DSA_TAG_AIROHA
+ tristate "Tag driver for Airoha switches"
+ select NET_DSA_TAG_MTK_COMMON
+ help
+ Say Y or M if you want to enable support for tagging frames for
+ Airoha switches.
+
config NET_DSA_TAG_KSZ
tristate "Tag driver for Microchip 8795/937x/9477/9893 families of switches"
help
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 555c07cfeb71..7aba189a715c 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -27,7 +27,7 @@ obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
-obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+obj-$(CONFIG_NET_DSA_TAG_MTK_COMMON) += tag_mtk.o
obj-$(CONFIG_NET_DSA_TAG_NONE) += tag_none.o
obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o
obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index b670e3c53e91..32befcbdf4be 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -11,6 +11,7 @@
#include "tag.h"

#define MTK_NAME "mtk"
+#define AIROHA_NAME "airoha"

#define MTK_HDR_LEN 4
#define MTK_HDR_XMIT_UNTAGGED 0
@@ -18,6 +19,9 @@
#define MTK_HDR_XMIT_TAGGED_TPID_88A8 2
#define MTK_HDR_RECV_SOURCE_PORT_MASK GENMASK(2, 0)
#define MTK_HDR_XMIT_DP_BIT_MASK GENMASK(5, 0)
+/* AN8855 doesn't support SA_DIS and Leaky VLAN
+ * control in tag as these bits doesn't exist.
+ */
#define MTK_HDR_XMIT_SA_DIS BIT(6)

static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
@@ -94,6 +98,7 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev)
return skb;
}

+#if IS_ENABLED(CONFIG_NET_DSA_TAG_MTK)
static const struct dsa_device_ops mtk_netdev_ops = {
.name = MTK_NAME,
.proto = DSA_TAG_PROTO_MTK,
@@ -102,8 +107,33 @@ static const struct dsa_device_ops mtk_netdev_ops = {
.needed_headroom = MTK_HDR_LEN,
};

-MODULE_DESCRIPTION("DSA tag driver for Mediatek switches");
-MODULE_LICENSE("GPL");
+DSA_TAG_DRIVER(mtk_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_MTK, MTK_NAME);
+#endif

-module_dsa_tag_driver(mtk_netdev_ops);
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_AIROHA)
+static const struct dsa_device_ops airoha_netdev_ops = {
+ .name = AIROHA_NAME,
+ .proto = DSA_TAG_PROTO_AIROHA,
+ .xmit = mtk_tag_xmit,
+ .rcv = mtk_tag_rcv,
+ .needed_headroom = MTK_HDR_LEN,
+};
+
+DSA_TAG_DRIVER(airoha_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_AIROHA, AIROHA_NAME);
+#endif
+
+static struct dsa_tag_driver *dsa_tag_driver_array[] = {
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_MTK)
+ &DSA_TAG_DRIVER_NAME(mtk_netdev_ops),
+#endif
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_AIROHA)
+ &DSA_TAG_DRIVER_NAME(airoha_netdev_ops),
+#endif
+};
+
+module_dsa_tag_drivers(dsa_tag_driver_array);
+
+MODULE_DESCRIPTION("DSA tag driver for Mediatek switches");
+MODULE_LICENSE("GPL");
--
2.51.0