e84665c9cb
The initial version of the DSA driver only supported a single switch
chip per network interface, while DSA-capable switch chips can be
interconnected to form a tree of switch chips. This patch adds support
for multiple switch chips on a network interface.
An example topology for a 16-port device with an embedded CPU is as
follows:
+-----+ +--------+ +--------+
| |eth0 10| switch |9 10| switch |
| CPU +----------+ +-------+ |
| | | chip 0 | | chip 1 |
+-----+ +---++---+ +---++---+
|| ||
|| ||
||1000baseT ||1000baseT
||ports 1-8 ||ports 9-16
This requires a couple of interdependent changes in the DSA layer:
- The dsa platform driver data needs to be extended: there is still
only one netdevice per DSA driver instance (eth0 in the example
above), but each of the switch chips in the tree needs its own
mii_bus device pointer, MII management bus address, and port name
array. (include/net/dsa.h) The existing in-tree dsa users need
some small changes to deal with this. (arch/arm)
- The DSA and Ethertype DSA tagging modules need to be extended to
use the DSA device ID field on receive and demultiplex the packet
accordingly, and fill in the DSA device ID field on transmit
according to which switch chip the packet is heading to.
(net/dsa/tag_{dsa,edsa}.c)
- The concept of "CPU port", which is the switch chip port that the
CPU is connected to (port 10 on switch chip 0 in the example), needs
to be extended with the concept of "upstream port", which is the
port on the switch chip that will bring us one hop closer to the CPU
(port 10 for both switch chips in the example above).
- The dsa platform data needs to specify which ports on which switch
chips are links to other switch chips, so that we can enable DSA
tagging mode on them. (For inter-switch links, we always use
non-EtherType DSA tagging, since it has lower overhead. The CPU
link uses dsa or edsa tagging depending on what the 'root' switch
chip supports.) This is done by specifying "dsa" for the given
port in the port array.
- The dsa platform data needs to be extended with information on via
which port to reach any given switch chip from any given switch chip.
This info is specified via the per-switch chip data struct ->rtable[]
array, which gives the nexthop ports for each of the other switches
in the tree.
For the example topology above, the dsa platform data would look
something like this:
static struct dsa_chip_data sw[2] = {
{
.mii_bus = &foo,
.sw_addr = 1,
.port_names[0] = "p1",
.port_names[1] = "p2",
.port_names[2] = "p3",
.port_names[3] = "p4",
.port_names[4] = "p5",
.port_names[5] = "p6",
.port_names[6] = "p7",
.port_names[7] = "p8",
.port_names[9] = "dsa",
.port_names[10] = "cpu",
.rtable = (s8 []){ -1, 9, },
}, {
.mii_bus = &foo,
.sw_addr = 2,
.port_names[0] = "p9",
.port_names[1] = "p10",
.port_names[2] = "p11",
.port_names[3] = "p12",
.port_names[4] = "p13",
.port_names[5] = "p14",
.port_names[6] = "p15",
.port_names[7] = "p16",
.port_names[10] = "dsa",
.rtable = (s8 []){ 10, -1, },
},
},
static struct dsa_platform_data pd = {
.netdev = &foo,
.nr_switches = 2,
.sw = sw,
};
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Tested-by: Gary Thomas <gary@mlbassoc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
133 lines
3.1 KiB
C
133 lines
3.1 KiB
C
/*
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* net/dsa/tag_trailer.c - Trailer tag format handling
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* Copyright (c) 2008-2009 Marvell Semiconductor
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/etherdevice.h>
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#include <linux/list.h>
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#include <linux/netdevice.h>
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#include "dsa_priv.h"
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int trailer_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct dsa_slave_priv *p = netdev_priv(dev);
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struct sk_buff *nskb;
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int padlen;
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u8 *trailer;
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dev->stats.tx_packets++;
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dev->stats.tx_bytes += skb->len;
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/*
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* We have to make sure that the trailer ends up as the very
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* last 4 bytes of the packet. This means that we have to pad
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* the packet to the minimum ethernet frame size, if necessary,
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* before adding the trailer.
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*/
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padlen = 0;
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if (skb->len < 60)
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padlen = 60 - skb->len;
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nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
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if (nskb == NULL) {
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kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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skb_reserve(nskb, NET_IP_ALIGN);
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skb_reset_mac_header(nskb);
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skb_set_network_header(nskb, skb_network_header(skb) - skb->head);
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skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head);
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skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
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kfree_skb(skb);
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if (padlen) {
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u8 *pad = skb_put(nskb, padlen);
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memset(pad, 0, padlen);
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}
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trailer = skb_put(nskb, 4);
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trailer[0] = 0x80;
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trailer[1] = 1 << p->port;
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trailer[2] = 0x10;
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trailer[3] = 0x00;
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nskb->protocol = htons(ETH_P_TRAILER);
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nskb->dev = p->parent->dst->master_netdev;
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dev_queue_xmit(nskb);
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return NETDEV_TX_OK;
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}
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static int trailer_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pt, struct net_device *orig_dev)
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{
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struct dsa_switch_tree *dst = dev->dsa_ptr;
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struct dsa_switch *ds;
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u8 *trailer;
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int source_port;
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if (unlikely(dst == NULL))
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goto out_drop;
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ds = dst->ds[0];
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skb = skb_unshare(skb, GFP_ATOMIC);
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if (skb == NULL)
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goto out;
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if (skb_linearize(skb))
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goto out_drop;
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trailer = skb_tail_pointer(skb) - 4;
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if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 ||
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(trailer[3] & 0xef) != 0x00 || trailer[3] != 0x00)
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goto out_drop;
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source_port = trailer[1] & 7;
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if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
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goto out_drop;
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pskb_trim_rcsum(skb, skb->len - 4);
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skb->dev = ds->ports[source_port];
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skb_push(skb, ETH_HLEN);
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skb->pkt_type = PACKET_HOST;
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skb->protocol = eth_type_trans(skb, skb->dev);
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skb->dev->stats.rx_packets++;
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skb->dev->stats.rx_bytes += skb->len;
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netif_receive_skb(skb);
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return 0;
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out_drop:
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kfree_skb(skb);
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out:
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return 0;
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}
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static struct packet_type trailer_packet_type __read_mostly = {
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.type = cpu_to_be16(ETH_P_TRAILER),
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.func = trailer_rcv,
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};
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static int __init trailer_init_module(void)
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{
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dev_add_pack(&trailer_packet_type);
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return 0;
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}
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module_init(trailer_init_module);
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static void __exit trailer_cleanup_module(void)
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{
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dev_remove_pack(&trailer_packet_type);
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}
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module_exit(trailer_cleanup_module);
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