[PATCH v7 3/4] net: dsa: add support for Atheros AR9331 TAG format

From: Oleksij Rempel
Date: Wed Dec 18 2019 - 03:02:47 EST


Add support for tag format used in Atheros AR9331 built-in switch.

Reviewed-by: Vivien Didelot <vivien.didelot@xxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
include/net/dsa.h | 2 +
net/dsa/Kconfig | 6 +++
net/dsa/Makefile | 1 +
net/dsa/tag_ar9331.c | 96 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 105 insertions(+)
create mode 100644 net/dsa/tag_ar9331.c

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 6767dc3f66c0..da5578db228e 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -43,6 +43,7 @@ struct phylink_link_state;
#define DSA_TAG_PROTO_SJA1105_VALUE 13
#define DSA_TAG_PROTO_KSZ8795_VALUE 14
#define DSA_TAG_PROTO_OCELOT_VALUE 15
+#define DSA_TAG_PROTO_AR9331_VALUE 16

enum dsa_tag_protocol {
DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE,
@@ -61,6 +62,7 @@ enum dsa_tag_protocol {
DSA_TAG_PROTO_SJA1105 = DSA_TAG_PROTO_SJA1105_VALUE,
DSA_TAG_PROTO_KSZ8795 = DSA_TAG_PROTO_KSZ8795_VALUE,
DSA_TAG_PROTO_OCELOT = DSA_TAG_PROTO_OCELOT_VALUE,
+ DSA_TAG_PROTO_AR9331 = DSA_TAG_PROTO_AR9331_VALUE,
};

struct packet_type;
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 1e6c3cac11e6..92663dcb3aa2 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -29,6 +29,12 @@ config NET_DSA_TAG_8021Q

Drivers which use these helpers should select this as dependency.

+config NET_DSA_TAG_AR9331
+ tristate "Tag driver for Atheros AR9331 SoC with built-in switch"
+ help
+ Say Y or M if you want to enable support for tagging frames for
+ the Atheros AR9331 SoC with built-in switch.
+
config NET_DSA_TAG_BRCM_COMMON
tristate
default n
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 9a482c38bdb1..108486cfdeef 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -5,6 +5,7 @@ dsa_core-y += dsa.o dsa2.o master.o port.o slave.o switch.o

# tagging formats
obj-$(CONFIG_NET_DSA_TAG_8021Q) += tag_8021q.o
+obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
diff --git a/net/dsa/tag_ar9331.c b/net/dsa/tag_ar9331.c
new file mode 100644
index 000000000000..466ffa92a474
--- /dev/null
+++ b/net/dsa/tag_ar9331.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Pengutronix, Oleksij Rempel <kernel@xxxxxxxxxxxxxx>
+ */
+
+
+#include <linux/bitfield.h>
+#include <linux/etherdevice.h>
+
+#include "dsa_priv.h"
+
+#define AR9331_HDR_LEN 2
+#define AR9331_HDR_VERSION 1
+
+#define AR9331_HDR_VERSION_MASK GENMASK(15, 14)
+#define AR9331_HDR_PRIORITY_MASK GENMASK(13, 12)
+#define AR9331_HDR_TYPE_MASK GENMASK(10, 8)
+#define AR9331_HDR_BROADCAST BIT(7)
+#define AR9331_HDR_FROM_CPU BIT(6)
+/* AR9331_HDR_RESERVED - not used or may be version field.
+ * According to the AR8216 doc it should 0b10. On AR9331 it is 0b11 on RX path
+ * and should be set to 0b11 to make it work.
+ */
+#define AR9331_HDR_RESERVED_MASK GENMASK(5, 4)
+#define AR9331_HDR_PORT_NUM_MASK GENMASK(3, 0)
+
+static struct sk_buff *ar9331_tag_xmit(struct sk_buff *skb,
+ struct net_device *dev)
+{
+ struct dsa_port *dp = dsa_slave_to_port(dev);
+ __le16 *phdr;
+ u16 hdr;
+
+ if (skb_cow_head(skb, 0) < 0)
+ return NULL;
+
+ phdr = skb_push(skb, AR9331_HDR_LEN);
+
+ hdr = FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);
+ hdr |= AR9331_HDR_FROM_CPU | dp->index;
+ /* 0b10 for AR8216 and 0b11 for AR9331 */
+ hdr |= AR9331_HDR_RESERVED_MASK;
+
+ phdr[0] = cpu_to_le16(hdr);
+
+ return skb;
+}
+
+static struct sk_buff *ar9331_tag_rcv(struct sk_buff *skb,
+ struct net_device *ndev,
+ struct packet_type *pt)
+{
+ u8 ver, port;
+ u16 hdr;
+
+ if (unlikely(!pskb_may_pull(skb, AR9331_HDR_LEN)))
+ return NULL;
+
+ hdr = le16_to_cpu(*(__le16 *)skb_mac_header(skb));
+
+ ver = FIELD_GET(AR9331_HDR_VERSION_MASK, hdr);
+ if (unlikely(ver != AR9331_HDR_VERSION)) {
+ netdev_warn_once(ndev, "%s:%i wrong header version 0x%2x\n",
+ __func__, __LINE__, hdr);
+ return NULL;
+ }
+
+ if (unlikely(hdr & AR9331_HDR_FROM_CPU)) {
+ netdev_warn_once(ndev, "%s:%i packet should not be from cpu 0x%2x\n",
+ __func__, __LINE__, hdr);
+ return NULL;
+ }
+
+ skb_pull_rcsum(skb, AR9331_HDR_LEN);
+
+ /* Get source port information */
+ port = FIELD_GET(AR9331_HDR_PORT_NUM_MASK, hdr);
+
+ skb->dev = dsa_master_find_slave(ndev, 0, port);
+ if (!skb->dev)
+ return NULL;
+
+ return skb;
+}
+
+static const struct dsa_device_ops ar9331_netdev_ops = {
+ .name = "ar9331",
+ .proto = DSA_TAG_PROTO_AR9331,
+ .xmit = ar9331_tag_xmit,
+ .rcv = ar9331_tag_rcv,
+ .overhead = AR9331_HDR_LEN,
+};
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_AR9331);
+module_dsa_tag_driver(ar9331_netdev_ops);
--
2.24.0