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dsa: add support for Microchip KSZ tail tagging
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Adding support for the Microchip KSZ switch family tail tagging.

Reviewed-by: Andrew Lunn <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Signed-off-by: Woojung Huh <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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WoojungHuh authored and davem330 committed Jun 1, 2017
1 parent 6c21a2a commit 8b8010f
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Showing 6 changed files with 112 additions and 0 deletions.
1 change: 1 addition & 0 deletions include/net/dsa.h
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ enum dsa_tag_protocol {
DSA_TAG_PROTO_BRCM,
DSA_TAG_PROTO_DSA,
DSA_TAG_PROTO_EDSA,
DSA_TAG_PROTO_KSZ,
DSA_TAG_PROTO_LAN9303,
DSA_TAG_PROTO_MTK,
DSA_TAG_PROTO_QCA,
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3 changes: 3 additions & 0 deletions net/dsa/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,9 @@ config NET_DSA_TAG_DSA
config NET_DSA_TAG_EDSA
bool

config NET_DSA_TAG_KSZ
bool

config NET_DSA_TAG_LAN9303
bool

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1 change: 1 addition & 0 deletions net/dsa/Makefile
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Expand Up @@ -6,6 +6,7 @@ dsa_core-y += dsa.o dsa2.o legacy.o port.o slave.o switch.o
dsa_core-$(CONFIG_NET_DSA_TAG_BRCM) += tag_brcm.o
dsa_core-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
dsa_core-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
dsa_core-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
dsa_core-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
dsa_core-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
dsa_core-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
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3 changes: 3 additions & 0 deletions net/dsa/dsa.c
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Expand Up @@ -49,6 +49,9 @@ const struct dsa_device_ops *dsa_device_ops[DSA_TAG_LAST] = {
#ifdef CONFIG_NET_DSA_TAG_EDSA
[DSA_TAG_PROTO_EDSA] = &edsa_netdev_ops,
#endif
#ifdef CONFIG_NET_DSA_TAG_KSZ
[DSA_TAG_PROTO_KSZ] = &ksz_netdev_ops,
#endif
#ifdef CONFIG_NET_DSA_TAG_LAN9303
[DSA_TAG_PROTO_LAN9303] = &lan9303_netdev_ops,
#endif
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3 changes: 3 additions & 0 deletions net/dsa/dsa_priv.h
Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,9 @@ extern const struct dsa_device_ops dsa_netdev_ops;
/* tag_edsa.c */
extern const struct dsa_device_ops edsa_netdev_ops;

/* tag_ksz.c */
extern const struct dsa_device_ops ksz_netdev_ops;

/* tag_lan9303.c */
extern const struct dsa_device_ops lan9303_netdev_ops;

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101 changes: 101 additions & 0 deletions net/dsa/tag_ksz.c
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@@ -0,0 +1,101 @@
/*
* net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
* Copyright (c) 2017 Microchip Technology
*
* 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/list.h>
#include <linux/slab.h>
#include <net/dsa.h>
#include "dsa_priv.h"

/* For Ingress (Host -> KSZ), 2 bytes are added before FCS.
* ---------------------------------------------------------------------------
* DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
* ---------------------------------------------------------------------------
* tag0 : Prioritization (not used now)
* tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
*
* For Egress (KSZ -> 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, 0x06=port7)
*/

#define KSZ_INGRESS_TAG_LEN 2
#define KSZ_EGRESS_TAG_LEN 1

static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_slave_priv *p = netdev_priv(dev);
struct sk_buff *nskb;
int padlen;
u8 *tag;

padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;

if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) {
nskb = skb;
} else {
nskb = alloc_skb(NET_IP_ALIGN + skb->len +
padlen + KSZ_INGRESS_TAG_LEN, GFP_ATOMIC);
if (!nskb) {
kfree_skb(skb);
return NULL;
}
skb_reserve(nskb, NET_IP_ALIGN);

skb_reset_mac_header(nskb);
skb_set_network_header(nskb,
skb_network_header(skb) - skb->head);
skb_set_transport_header(nskb,
skb_transport_header(skb) - skb->head);
skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
kfree_skb(skb);
}

/* skb is freed when it fails */
if (skb_put_padto(nskb, nskb->len + padlen))
return NULL;

tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
tag[0] = 0;
tag[1] = 1 << p->dp->index; /* destination port */

return nskb;
}

struct sk_buff *ksz_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct dsa_switch_tree *dst = dev->dsa_ptr;
struct dsa_switch *ds;
u8 *tag;
int source_port;

ds = dst->cpu_dp->ds;

tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;

source_port = tag[0] & 7;
if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
return NULL;

pskb_trim_rcsum(skb, skb->len - KSZ_EGRESS_TAG_LEN);

skb->dev = ds->ports[source_port].netdev;

return skb;
}

const struct dsa_device_ops ksz_netdev_ops = {
.xmit = ksz_xmit,
.rcv = ksz_rcv,
};

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