[PATCH v9 net-next 05/11] net: dsa: tag_ksz: add tag handling for Microchip LAN937x

Prasanna Vengateshan
2022-03-18T08:56:56Z

The Microchip LAN937X switches have a tagging protocol which is
very similar to KSZ tagging. So that the implementation is added to
tag_ksz.c and reused common APIs

Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
---
include/net/dsa.h | 2 ++
net/dsa/Kconfig | 4 ++--
net/dsa/tag_ksz.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 9bfe984fcdbf..4f0b82a70a07 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_LAN937X_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_LAN937X = DSA_TAG_PROTO_LAN937X_VALUE,
};

struct dsa_switch;
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 8cb87b5067ee..6d0414c9f7f4 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -87,10 +87,10 @@ config NET_DSA_TAG_MTK
Mediatek switches.

config NET_DSA_TAG_KSZ
- tristate "Tag driver for Microchip 8795/9477/9893 families of switches"
+ tristate "Tag driver for Microchip 8795/937x/9477/9893 families of switches"
help
Say Y if you want to enable support for tagging frames for the
- Microchip 8795/9477/9893 families of switches.
+ Microchip 8795/937x/9477/9893 families of switches.

config NET_DSA_TAG_OCELOT
tristate "Tag driver for Ocelot family of switches, using NPI port"
diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 3509fc967ca9..38fa19c1e2d5 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -193,10 +193,69 @@ static const struct dsa_device_ops ksz9893_netdev_ops = {
DSA_TAG_DRIVER(ksz9893_netdev_ops);
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);

+/* For xmit, 2 bytes are added before FCS.
+ * ---------------------------------------------------------------------------
+ * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
+ * ---------------------------------------------------------------------------
+ * tag0 : represents tag override, lookup and valid
+ * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x80=port8)
+ *
+ * For rcv, 1 byte is added before FCS.
+ * ---------------------------------------------------------------------------
+ * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
+ * ---------------------------------------------------------------------------
+ * tag0 : zero-based value represents port
+ * (eg, 0x00=port1, 0x02=port3, 0x07=port8)
+ */
+#define LAN937X_EGRESS_TAG_LEN 2
+
+#define LAN937X_TAIL_TAG_BLOCKING_OVERRIDE BIT(11)
+#define LAN937X_TAIL_TAG_LOOKUP BIT(12)
+#define LAN937X_TAIL_TAG_VALID BIT(13)
+#define LAN937X_TAIL_TAG_PORT_MASK 7
+
+static struct sk_buff *lan937x_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ struct dsa_port *dp = dsa_slave_to_port(dev);
+ const struct ethhdr *hdr = eth_hdr(skb);
+ __be16 *tag;
+ u16 val;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
+ return NULL;
+
+ tag = skb_put(skb, LAN937X_EGRESS_TAG_LEN);
+
+ val = BIT(dp->index);
+
+ if (is_link_local_ether_addr(hdr->h_dest))
+ val |= LAN937X_TAIL_TAG_BLOCKING_OVERRIDE;
+
+ /* Tail tag valid bit - This bit should always be set by the CPU */
+ val |= LAN937X_TAIL_TAG_VALID;
+
+ put_unaligned_be16(val, tag);
+
+ return skb;
+}
+
+static const struct dsa_device_ops lan937x_netdev_ops = {
+ .name = "lan937x",
+ .proto = DSA_TAG_PROTO_LAN937X,
+ .xmit = lan937x_xmit,
+ .rcv = ksz9477_rcv,
+ .needed_tailroom = LAN937X_EGRESS_TAG_LEN,
+};
+
+DSA_TAG_DRIVER(lan937x_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN937X);
+
static struct dsa_tag_driver *dsa_tag_driver_array[] = {
&DSA_TAG_DRIVER_NAME(ksz8795_netdev_ops),
&DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
&DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
+ &DSA_TAG_DRIVER_NAME(lan937x_netdev_ops),
};

module_dsa_tag_drivers(dsa_tag_driver_array);
--
2.30.2