Message-ID: <20080925164124.GC25190@xi.wantstofly.org>
Date:	Thu, 25 Sep 2008 18:41:24 +0200
From:	Lennert Buytenhek <buytenh@...tstofly.org>
To:	netdev@...r.kernel.org
Cc:	Andy Fleming <afleming@...escale.com>,
	Imre Kaloz <kaloz@...nwrt.org>,
	Ashish Karkare <akarkare@...vell.com>,
	Nicolas Pitre <nico@....org>, Dirk Teurlings <dirk@...xia.nl>,
	Peter van Valderen <p.v.valderen@...il.com>
Subject: [PATCH 2/4] [NET] dsa: add support for original DSA tagging format

Most of the DSA switches currently in the field do not support the
Ethertype DSA tagging format that one of the previous patches added
support for, but only the older, original DSA tagging format.

The original DSA tagging format carries the same information as the
Ethertype DSA tagging format, but with the difference that it does not
have an ethertype field.  In other words, when receiving a packet that
is tagged with an original DSA tag, there is no way of telling in
eth_type_trans() that this packet is in fact a DSA-tagged packet.

This patch adds a hook into eth_type_trans() which is only compiled in
if support for an older switch chip (one that doesn't support Ethertype
DSA) is selected, which checks whether there is a DSA switch driver
instance attached to this network device which uses the old tag format.
If so, it sets the protocol field to ETH_P_DSA without looking at the
packet, so that the packet ends up in the right place.

Signed-off-by: Lennert Buytenhek <buytenh@...vell.com>
---
 include/linux/if_ether.h  |    1 +
 include/linux/netdevice.h |   11 +++
 include/net/dsa.h         |    2 +
 net/dsa/Kconfig           |    4 +
 net/dsa/Makefile          |    1 +
 net/dsa/dsa.c             |   13 +++
 net/dsa/dsa_priv.h        |    6 +-
 net/dsa/marvell.c         |   23 +++--
 net/dsa/slave.c           |    5 +
 net/dsa/tag_dsa.c         |  203 +++++++++++++++++++++++++++++++++++++++++++++
 net/ethernet/eth.c        |    8 ++
 11 files changed, 266 insertions(+), 11 deletions(-)
 create mode 100644 net/dsa/tag_dsa.c

diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
index a85f5a2..864982b 100644
--- a/include/linux/if_ether.h
+++ b/include/linux/if_ether.h
@@ -100,6 +100,7 @@
 #define ETH_P_ECONET	0x0018		/* Acorn Econet			*/
 #define ETH_P_HDLC	0x0019		/* HDLC frames			*/
 #define ETH_P_ARCNET	0x001A		/* 1A for ArcNet :-)            */
+#define ETH_P_DSA	0x001B		/* Distributed Switch Arch.	*/
 
 /*
  *	This is an Ethernet frame header.
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f67435d..d3bdf3b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -42,6 +42,7 @@
 #include <linux/workqueue.h>
 
 #include <net/net_namespace.h>
+#include <net/dsa.h>
 
 struct vlan_group;
 struct ethtool_ops;
@@ -801,6 +802,16 @@ void dev_net_set(struct net_device *dev, struct net *net)
 #endif
 }
 
+static inline int netdev_uses_ethertypeless_dsa_tags(struct net_device *dev)
+{
+#ifdef CONFIG_NET_DSA_TAG_DSA
+	if (dev->dsa_ptr != NULL)
+		return dsa_uses_ethertypeless_tags(dev->dsa_ptr);
+#endif
+
+	return 0;
+}
+
 /**
  *	netdev_priv - access network device private data
  *	@dev: network device
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 4839894..b706e29 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -20,5 +20,7 @@ struct dsa_platform_data {
 	char		*port_names[DSA_MAX_PORTS];
 };
 
+int dsa_uses_ethertypeless_tags(void *dsa_ptr);
+
 
 #endif
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index 8618508..e8937f0 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -10,6 +10,10 @@ menuconfig NET_DSA
 if NET_DSA
 
 # tagging formats
+config NET_DSA_TAG_DSA
+	bool
+	default n
+
 config NET_DSA_TAG_EDSA
 	bool
 	default n
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 6c36d10..42d0e46 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -1,4 +1,5 @@
 # tagging formats
+obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
 obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
 
 # switch drivers
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index e94bfe6..e2528a4 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -187,6 +187,19 @@ static void dsa_switch_destroy(struct dsa_switch *ds)
 	BUG();
 }
 
+int dsa_uses_ethertypeless_tags(void *dsa_ptr)
+{
+	struct dsa_switch *ds = dsa_ptr;
+
+	/*
+	 * The original DSA tag format has no ethertype, which means
+	 * that we need to add a little hack to the receive path to
+	 * make sure that received frames get the right ->protocol
+	 * assigned to them.
+	 */
+	return !!(ds->tag_type == TAG_DSA_MASK);
+}
+
 
 /* link polling *************************************************************/
 static void dsa_link_poll_work(struct work_struct *ugly)
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 78246bf..6b34c2e 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -6,7 +6,8 @@
 #include <linux/netdevice.h>
 
 enum dsa_tag_type {
-	TAG_EDSA_MASK = 1,
+	TAG_DSA_MASK = 1,
+	TAG_EDSA_MASK = 2,
 };
 
 struct dsa_switch {
@@ -91,6 +92,9 @@ void unregister_switch_driver(struct dsa_switch_driver *type);
 void dsa_slave_mii_bus_init(struct dsa_switch *ds);
 struct net_device *dsa_slave_create(struct dsa_switch *ds, int port);
 
+/* tag_dsa.c */
+int dsa_xmit(struct sk_buff *skb, struct net_device *dev);
+
 /* tag_edsa.c */
 int edsa_xmit(struct sk_buff *skb, struct net_device *dev);
 
diff --git a/net/dsa/marvell.c b/net/dsa/marvell.c
index 7f571ab..9b89f0b 100644
--- a/net/dsa/marvell.c
+++ b/net/dsa/marvell.c
@@ -668,15 +668,18 @@ static int emerald_setup_port(struct dsa_switch *ds, int p)
 
 	/*
 	 * Port Control: disable Drop-on-Unlock, disable Drop-on-Lock,
-	 * configure the EDSA tagging mode if this is the CPU port,
-	 * disable Header mode, enable IGMP/MLD snooping, disable VLAN
-	 * tunneling, determine priority by looking at 802.1p and IP
-	 * priority fields (IP prio has precedence), and set STP state
-	 * to Forwarding.  Finally, if this is the CPU port, additionally
-	 * enable forwarding of unknown unicast and multicast addresses.
+	 * configure the requested (DSA/EDSA) tagging mode if this is
+	 * the CPU port, disable Header mode, enable IGMP/MLD snooping,
+	 * disable VLAN tunneling, determine priority by looking at
+	 * 802.1p and IP priority fields (IP prio has precedence), and
+	 * set STP state to Forwarding.  Finally, if this is the CPU
+	 * port, additionally enable forwarding of unknown unicast and
+	 * multicast addresses.
 	 */
 	ret = reg_write(ds, addr, 0x04,
-			(p == ds->cpu_port) ? 0x373f : 0x0433);
+			(p == ds->cpu_port) ?
+			 (ds->tag_type == TAG_DSA_MASK) ? 0x053f : 0x373f :
+			 0x0433);
 	if (ret < 0)
 		return ret;
 
@@ -895,7 +898,7 @@ static struct dsa_switch_driver marvell_switch_drivers[] = {
 #ifdef CONFIG_NET_DSA_EMERALD
 	{
 		.name			= "Marvell 88E6123",
-		.tag_methods		= TAG_EDSA_MASK,
+		.tag_methods		= TAG_DSA_MASK | TAG_EDSA_MASK,
 		.priv_size		= sizeof(struct priv_state),
 		.probe			= emerald6123_probe,
 		.setup			= emerald_setup,
@@ -908,7 +911,7 @@ static struct dsa_switch_driver marvell_switch_drivers[] = {
 		.get_sset_count		= marvell_get_sset_count,
 	}, {
 		.name			= "Marvell 88E6161",
-		.tag_methods		= TAG_EDSA_MASK,
+		.tag_methods		= TAG_DSA_MASK | TAG_EDSA_MASK,
 		.priv_size		= sizeof(struct priv_state),
 		.probe			= emerald6161_probe,
 		.setup			= emerald_setup,
@@ -921,7 +924,7 @@ static struct dsa_switch_driver marvell_switch_drivers[] = {
 		.get_sset_count		= marvell_get_sset_count,
 	}, {
 		.name			= "Marvell 88E6165",
-		.tag_methods		= TAG_EDSA_MASK,
+		.tag_methods		= TAG_DSA_MASK | TAG_EDSA_MASK,
 		.priv_size		= sizeof(struct priv_state),
 		.probe			= emerald6165_probe,
 		.setup			= emerald_setup,
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 8273e15..b0b9498 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -232,6 +232,11 @@ struct net_device *dsa_slave_create(struct dsa_switch *ds, int port)
 	slave_dev->open = dsa_slave_open;
 	slave_dev->stop = dsa_slave_close;
 	switch (ds->tag_type) {
+#ifdef CONFIG_NET_DSA_TAG_DSA
+	case TAG_DSA_MASK:
+		slave_dev->hard_start_xmit = dsa_xmit;
+		break;
+#endif
 #ifdef CONFIG_NET_DSA_TAG_EDSA
 	case TAG_EDSA_MASK:
 		slave_dev->hard_start_xmit = edsa_xmit;
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
new file mode 100644
index 0000000..5357165
--- /dev/null
+++ b/net/dsa/tag_dsa.c
@@ -0,0 +1,203 @@
+/*
+ * net/dsa/dsa.c - (Non-ethertype) DSA tagging
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/ip.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/rtnetlink.h>
+#include <net/dsa.h>
+#include "dsa_priv.h"
+
+#define DSA_HLEN	4
+
+int dsa_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	char *dsa_header;
+
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+
+	/*
+	 * Convert the outermost 802.1q tag to a DSA tag for tagged
+	 * packets, or insert a DSA tag between the addresses and
+	 * the ethertype field for untagged packets.
+	 */
+	if (skb->protocol == htons(ETH_P_8021Q)) {
+		if (skb_cow_head(skb, 0) < 0)
+			goto out_free;
+
+		/*
+		 * Construct tagged FROM_CPU DSA tag from 802.1q tag.
+		 */
+		dsa_header = skb->data + 2 * ETH_ALEN;
+		dsa_header[0] = 0x60;
+		dsa_header[1] = p->port << 3;
+
+		/*
+		 * Move CFI field from byte 2 to byte 1.
+		 */
+		if (dsa_header[2] & 0x10) {
+			dsa_header[1] |= 0x01;
+			dsa_header[2] &= ~0x10;
+		}
+	} else {
+		if (skb_cow_head(skb, DSA_HLEN) < 0)
+			goto out_free;
+		skb_push(skb, DSA_HLEN);
+
+		memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
+
+		/*
+		 * Construct untagged FROM_CPU DSA tag.
+		 */
+		dsa_header = skb->data + 2 * ETH_ALEN;
+		dsa_header[0] = 0x40;
+		dsa_header[1] = p->port << 3;
+		dsa_header[2] = 0x00;
+		dsa_header[3] = 0x00;
+	}
+
+	skb->protocol = htons(ETH_P_DSA);
+
+	skb->dev = p->parent->master_dev;
+	dev_queue_xmit(skb);
+
+	return NETDEV_TX_OK;
+
+out_free:
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static int dsa_rcv(struct sk_buff *skb, struct net_device *dev,
+		   struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct dsa_switch *ds = dev->dsa_ptr;
+	u8 *dsa_header;
+	int source_port;
+
+	if (unlikely(ds == NULL))
+		goto out_drop;
+
+	skb = skb_unshare(skb, GFP_ATOMIC);
+	if (skb == NULL)
+		goto out;
+
+	if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
+		goto out_drop;
+
+	/*
+	 * The ethertype field is part of the DSA header.
+	 */
+	dsa_header = skb->data - 2;
+
+	/*
+	 * Check that frame type is either TO_CPU or FORWARD, and
+	 * that the source device is zero.
+	 */
+	if ((dsa_header[0] & 0xdf) != 0x00 && (dsa_header[0] & 0xdf) != 0xc0)
+		goto out_drop;
+
+	/*
+	 * Check that the source port is a registered DSA port.
+	 */
+	source_port = (dsa_header[1] >> 3) & 0x1f;
+	if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
+		goto out_drop;
+
+	/*
+	 * Convert the DSA header to an 802.1q header if the 'tagged'
+	 * bit in the DSA header is set.  If the 'tagged' bit is clear,
+	 * delete the DSA header entirely.
+	 */
+	if (dsa_header[0] & 0x20) {
+		u8 new_header[4];
+
+		/*
+		 * Insert 802.1q ethertype and copy the VLAN-related
+		 * fields, but clear the bit that will hold CFI (since
+		 * DSA uses that bit location for another purpose).
+		 */
+		new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
+		new_header[1] = ETH_P_8021Q & 0xff;
+		new_header[2] = dsa_header[2] & ~0x10;
+		new_header[3] = dsa_header[3];
+
+		/*
+		 * Move CFI bit from its place in the DSA header to
+		 * its 802.1q-designated place.
+		 */
+		if (dsa_header[1] & 0x01)
+			new_header[2] |= 0x10;
+
+		/*
+		 * Update packet checksum if skb is CHECKSUM_COMPLETE.
+		 */
+		if (skb->ip_summed == CHECKSUM_COMPLETE) {
+			__wsum c = skb->csum;
+			c = csum_add(c, csum_partial(new_header + 2, 2, 0));
+			c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0));
+			skb->csum = c;
+		}
+
+		memcpy(dsa_header, new_header, DSA_HLEN);
+	} else {
+		/*
+		 * Remove DSA tag and update checksum.
+		 */
+		skb_pull_rcsum(skb, DSA_HLEN);
+		memmove(skb->data - ETH_HLEN,
+			skb->data - ETH_HLEN - DSA_HLEN,
+			2 * ETH_ALEN);
+	}
+
+	skb->dev = ds->ports[source_port];
+	skb_push(skb, ETH_HLEN);
+	skb->protocol = eth_type_trans(skb, skb->dev);
+
+	skb->dev->last_rx = jiffies;
+	skb->dev->stats.rx_packets++;
+	skb->dev->stats.rx_bytes += skb->len;
+
+	netif_receive_skb(skb);
+
+	return 0;
+
+out_drop:
+	kfree_skb(skb);
+out:
+	return 0;
+}
+
+static struct packet_type dsa_packet_type = {
+	.type	= __constant_htons(ETH_P_DSA),
+	.func	= dsa_rcv,
+};
+
+static int __init dsa_init_module(void)
+{
+	dev_add_pack(&dsa_packet_type);
+	return 0;
+}
+module_init(dsa_init_module);
+
+static void __exit dsa_cleanup_module(void)
+{
+	dev_remove_pack(&dsa_packet_type);
+}
+module_exit(dsa_cleanup_module);
+
+MODULE_AUTHOR("Lennert Buytenhek <buytenh@...tstofly.org>");
+MODULE_DESCRIPTION("DSA tagging");
+MODULE_LICENSE("GPL");
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index a80839b..0db59e7 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -57,6 +57,7 @@
 #include <net/sock.h>
 #include <net/ipv6.h>
 #include <net/ip.h>
+#include <net/dsa.h>
 #include <asm/uaccess.h>
 #include <asm/system.h>
 
@@ -184,6 +185,13 @@ __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
 			skb->pkt_type = PACKET_OTHERHOST;
 	}
 
+	/*
+	 * Some variants of DSA tagging don't have an ethertype
+	 * field at all.
+	 */
+	if (netdev_uses_ethertypeless_dsa_tags(dev))
+		return htons(ETH_P_DSA);
+
 	if (ntohs(eth->h_proto) >= 1536)
 		return eth->h_proto;
 
-- 
1.5.6.4
--
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