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Subject[PATCH net-next 2/8] net: dsa: tag_ksz: add tag handling for Microchip LAN937x
Date
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>
---
include/net/dsa.h | 2 ++
net/dsa/Kconfig | 4 +--
net/dsa/tag_ksz.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 2f5435d3d1db..b9bc7a9a8c15 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -47,6 +47,7 @@ struct phylink_link_state;
#define DSA_TAG_PROTO_RTL4_A_VALUE 17
#define DSA_TAG_PROTO_HELLCREEK_VALUE 18
#define DSA_TAG_PROTO_XRS700X_VALUE 19
+#define DSA_TAG_PROTO_LAN937X_VALUE 20

enum dsa_tag_protocol {
DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
@@ -69,6 +70,7 @@ enum dsa_tag_protocol {
DSA_TAG_PROTO_RTL4_A = DSA_TAG_PROTO_RTL4_A_VALUE,
DSA_TAG_PROTO_HELLCREEK = DSA_TAG_PROTO_HELLCREEK_VALUE,
DSA_TAG_PROTO_XRS700X = DSA_TAG_PROTO_XRS700X_VALUE,
+ DSA_TAG_PROTO_LAN937X = DSA_TAG_PROTO_LAN937X_VALUE,
};

struct packet_type;
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 2d226a5c085f..217fa0f8d13e 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -92,10 +92,10 @@ 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 8795/9477/9893/937x 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 8795/9477/9893/937x families of switches.

config NET_DSA_TAG_RTL4_A
tristate "Tag driver for Realtek 4 byte protocol A tags"
diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 4820dbcedfa2..6fac39c2b7d5 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -190,10 +190,84 @@ 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 Ingress (Host -> LAN937x), 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 Egress (LAN937x -> Host), 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_INGRESS_TAG_LEN 2
+
+#define LAN937X_TAIL_TAG_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);
+ __be16 *tag;
+ u8 *addr;
+ u16 val;
+
+ /* Tag encoding */
+ tag = skb_put(skb, LAN937X_INGRESS_TAG_LEN);
+ addr = skb_mac_header(skb);
+
+ val = BIT(dp->index);
+
+ if (is_link_local_ether_addr(addr))
+ val |= LAN937X_TAIL_TAG_OVERRIDE;
+
+ /* Tail tag valid bit - This bit should always be set by the CPU*/
+ val |= LAN937X_TAIL_TAG_VALID;
+
+ *tag = cpu_to_be16(val);
+
+ return skb;
+}
+
+static struct sk_buff *lan937x_rcv(struct sk_buff *skb, struct net_device *dev,
+ struct packet_type *pt)
+{
+ /* Tag decoding */
+ u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
+ unsigned int port = tag[0] & LAN937X_TAIL_TAG_PORT_MASK;
+ unsigned int len = KSZ_EGRESS_TAG_LEN;
+
+ /* Extra 4-bytes PTP timestamp */
+ if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
+ len += KSZ9477_PTP_TAG_LEN;
+
+ return ksz_common_rcv(skb, dev, port, len);
+}
+
+static const struct dsa_device_ops lan937x_netdev_ops = {
+ .name = "lan937x",
+ .proto = DSA_TAG_PROTO_LAN937X,
+ .xmit = lan937x_xmit,
+ .rcv = lan937x_rcv,
+ .overhead = LAN937X_INGRESS_TAG_LEN,
+ .tail_tag = true,
+};
+
+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);
--
2.25.1
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