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/*
* 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"
/* Typically only one byte is used for tail tag. */
#define KSZ_EGRESS_TAG_LEN 1
static struct sk_buff *ksz_common_xmit(struct sk_buff *skb,
struct net_device *dev, int len)
{
struct sk_buff *nskb;
int padlen;
padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
if (skb_tailroom(skb) >= padlen + len) {
/* Let dsa_slave_xmit() free skb */
if (__skb_put_padto(skb, skb->len + padlen, false))
return NULL;
nskb = skb;
} else {
nskb = alloc_skb(NET_IP_ALIGN + skb->len +
padlen + len, GFP_ATOMIC);
if (!nskb)
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));
/* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free
* skb
*/
if (skb_put_padto(nskb, nskb->len + padlen))
return NULL;
consume_skb(skb);
}
return nskb;
}
static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
struct net_device *dev,
unsigned int port, unsigned int len)
{
skb->dev = dsa_master_find_slave(dev, 0, port);
if (!skb->dev)
return NULL;
pskb_trim_rcsum(skb, skb->len - len);
return skb;
}
/*
* For Ingress (Host -> KSZ9477), 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 (KSZ9477 -> 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 KSZ9477_INGRESS_TAG_LEN 2
#define KSZ9477_PTP_TAG_LEN 4
#define KSZ9477_PTP_TAG_INDICATION 0x80
#define KSZ9477_TAIL_TAG_OVERRIDE BIT(9)
#define KSZ9477_TAIL_TAG_LOOKUP BIT(10)
static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
struct sk_buff *nskb;
u16 *tag;
u8 *addr;
nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
if (!nskb)
return NULL;
/* Tag encoding */
tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN);
addr = skb_mac_header(nskb);
*tag = BIT(dp->index);
if (is_link_local_ether_addr(addr))
*tag |= KSZ9477_TAIL_TAG_OVERRIDE;
*tag = cpu_to_be16(*tag);
return nskb;
}
static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt)
{
/* Tag decoding */
u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
unsigned int port = tag[0] & 7;
unsigned int len = KSZ_EGRESS_TAG_LEN;
/* Extra 4-bytes PTP timestamp */
if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
len += KSZ9477_PTP_TAG_LEN;
return ksz_common_rcv(skb, dev, port, len);
}
const struct dsa_device_ops ksz9477_netdev_ops = {
.xmit = ksz9477_xmit,
.rcv = ksz9477_rcv,
.overhead = KSZ9477_INGRESS_TAG_LEN,
};
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