Merge branch 'dsa-LAN9303'

Juergen Borleis says:

====================
net: dsa: add SMSC/Microchip LAN9303 three port ethernet switch driver

The LAN9303 is a three port 10/100 ethernet switch with integrated phys
for the two external ethernet ports. The third port is an RMII/MII
interface to a host master network interface (e.g. fixed link).

While the LAN9303 device itself supports offload packet processing, this
driver does not make use of it yet. This driver just configures the device
to provide two separate network interfaces (which is the default state of
a DSA device).

Please note: the "MDIO managed mode" driver part isn't tested yet. I have
used and tested the "I2C managed mode" only.

Changes in v6:

- fix support to use the driver as a module (core, i2c and mdio)
- license info added in all parts of the driver (for module support)

Changes in v5:

- add missing include file to 'net/dsa/tag_lan9303.c'

Changes in v4:

- rebased on net-next, 'net/dsa/tag_lan9303.c' adapted to changed API

Changes in v3:

- 'ds_to_lan9303()' removed
- special PHY reg MII_LAN911X_SPECIAL_CONTROL_STATUS mapping removed
- compatible strings for I2C and MDIO are now different
- MDIO-managed-mode devicetree binding added (still compile time tested only)

Changes in v2:

- code moved to 'drivers/net/dsa'
- timeouts in completion wait loops
- macros instead of various magic numbers
- development code removed
- devicetree property names changed
- devicetree example adapted
- tried to avoid to mix 'switching' and 'forwarding'...

Comments are welcome.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 152 insertions, 0 deletions

diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index aa21f49f1215..81a0868edb1d 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -33,4 +33,8 @@ config NET_DSA_TAG_QCA
 
 config NET_DSA_TAG_MTK
 	bool
+
+config NET_DSA_TAG_LAN9303
+	bool
+
 endif
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 11a082d7e103..0b747d75e65a 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -9,3 +9,4 @@ dsa_core-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
 dsa_core-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
 dsa_core-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
 dsa_core-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+dsa_core-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index e117047174fc..26130ae438da 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -58,6 +58,9 @@ const struct dsa_device_ops *dsa_device_ops[DSA_TAG_LAST] = {
 #ifdef CONFIG_NET_DSA_TAG_MTK
 	[DSA_TAG_PROTO_MTK] = &mtk_netdev_ops,
 #endif
+#ifdef CONFIG_NET_DSA_TAG_LAN9303
+	[DSA_TAG_PROTO_LAN9303] = &lan9303_netdev_ops,
+#endif
 	[DSA_TAG_PROTO_NONE] = &none_ops,
 };
 
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index ab397c07880f..f4a88e485213 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -93,4 +93,7 @@ extern const struct dsa_device_ops qca_netdev_ops;
 /* tag_mtk.c */
 extern const struct dsa_device_ops mtk_netdev_ops;
 
+/* tag_lan9303.c */
+extern const struct dsa_device_ops lan9303_netdev_ops;
+
 #endif
diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c
new file mode 100644
index 000000000000..563b6c8fe445
--- /dev/null
+++ b/net/dsa/tag_lan9303.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/etherdevice.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <net/dsa.h>
+#include "dsa_priv.h"
+
+/* To define the outgoing port and to discover the incoming port a regular
+ * VLAN tag is used by the LAN9303. But its VID meaning is 'special':
+ *
+ *       Dest MAC       Src MAC        TAG    Type
+ * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
+ *                                |<------->|
+ * TAG:
+ *    |<------------->|
+ *    |  1  2 | 3  4  |
+ *      TPID    VID
+ *     0x8100
+ *
+ * VID bit 3 indicates a request for an ALR lookup.
+ *
+ * If VID bit 3 is zero, then bits 0 and 1 specify the destination port
+ * (0, 1, 2) or broadcast (3) or the source port (1, 2).
+ *
+ * VID bit 4 is used to specify if the STP port state should be overridden.
+ * Required when no forwarding between the external ports should happen.
+ */
+
+#define LAN9303_TAG_LEN 4
+#define LAN9303_MAX_PORTS 3
+
+static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	u16 *lan9303_tag;
+
+	/* insert a special VLAN tag between the MAC addresses
+	 * and the current ethertype field.
+	 */
+	if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) {
+		dev_dbg(&dev->dev,
+			"Cannot make room for the special tag. Dropping packet\n");
+		goto out_free;
+	}
+
+	/* provide 'LAN9303_TAG_LEN' bytes additional space */
+	skb_push(skb, LAN9303_TAG_LEN);
+
+	/* make room between MACs and Ether-Type */
+	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
+
+	lan9303_tag = (u16 *)(skb->data + 2 * ETH_ALEN);
+	lan9303_tag[0] = htons(ETH_P_8021Q);
+	lan9303_tag[1] = htons(p->dp->index | BIT(4));
+
+	return skb;
+out_free:
+	kfree_skb(skb);
+	return NULL;
+}
+
+static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
+			struct packet_type *pt, struct net_device *orig_dev)
+{
+	u16 *lan9303_tag;
+	struct dsa_switch_tree *dst = dev->dsa_ptr;
+	struct dsa_switch *ds;
+	unsigned int source_port;
+
+	if (unlikely(!dst)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet, due to missing switch tree device\n");
+		return NULL;
+	}
+
+	ds = dst->ds[0];
+
+	if (unlikely(!ds)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet, due to missing DSA switch device\n");
+		return NULL;
+	}
+
+	if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
+		dev_warn_ratelimited(&dev->dev,
+				     "Dropping packet, cannot pull\n");
+		return NULL;
+	}
+
+	/* '->data' points into the middle of our special VLAN tag information:
+	 *
+	 * ~ MAC src   | 0x81 | 0x00 | 0xyy | 0xzz | ether type
+	 *                           ^
+	 *                        ->data
+	 */
+	lan9303_tag = (u16 *)(skb->data - 2);
+
+	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
+		return NULL;
+	}
+
+	source_port = ntohs(lan9303_tag[1]) & 0x3;
+
+	if (source_port >= LAN9303_MAX_PORTS) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
+		return NULL;
+	}
+
+	if (!ds->ports[source_port].netdev) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid netdev or device\n");
+		return NULL;
+	}
+
+	/* remove the special VLAN tag between the MAC addresses
+	 * and the current ethertype field.
+	 */
+	skb_pull_rcsum(skb, 2 + 2);
+	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
+		2 * ETH_ALEN);
+
+	/* forward the packet to the dedicated interface */
+	skb->dev = ds->ports[source_port].netdev;
+
+	return skb;
+}
+
+const struct dsa_device_ops lan9303_netdev_ops = {
+	.xmit = lan9303_xmit,
+	.rcv = lan9303_rcv,
+};