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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2022 Schneider Electric
*
* Clément Léger <clement.leger@bootlin.com>
*/
#include <linux/bitfield.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <net/dsa.h>
#include "tag.h"
/* To define the outgoing port and to discover the incoming port a TAG is
* inserted after Src MAC :
*
* Dest MAC Src MAC TAG Type
* ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 5 6 7 8 | 1 2 |...
* |<--------------->|
*
* See struct a5psw_tag for layout
*/
#define A5PSW_NAME "a5psw"
#define ETH_P_DSA_A5PSW 0xE001
#define A5PSW_TAG_LEN 8
#define A5PSW_CTRL_DATA_FORCE_FORWARD BIT(0)
/* This is both used for xmit tag and rcv tagging */
#define A5PSW_CTRL_DATA_PORT GENMASK(3, 0)
struct a5psw_tag {
__be16 ctrl_tag;
__be16 ctrl_data;
__be16 ctrl_data2_hi;
__be16 ctrl_data2_lo;
};
static struct sk_buff *a5psw_tag_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_port *dp = dsa_user_to_port(dev);
struct a5psw_tag *ptag;
u32 data2_val;
BUILD_BUG_ON(sizeof(*ptag) != A5PSW_TAG_LEN);
/* The Ethernet switch we are interfaced with needs packets to be at
* least 60 bytes otherwise they will be discarded when they enter the
* switch port logic.
*/
if (__skb_put_padto(skb, ETH_ZLEN, false))
return NULL;
/* provide 'A5PSW_TAG_LEN' bytes additional space */
skb_push(skb, A5PSW_TAG_LEN);
/* make room between MACs and Ether-Type to insert tag */
dsa_alloc_etype_header(skb, A5PSW_TAG_LEN);
ptag = dsa_etype_header_pos_tx(skb);
data2_val = FIELD_PREP(A5PSW_CTRL_DATA_PORT, BIT(dp->index));
ptag->ctrl_tag = htons(ETH_P_DSA_A5PSW);
ptag->ctrl_data = htons(A5PSW_CTRL_DATA_FORCE_FORWARD);
ptag->ctrl_data2_lo = htons(data2_val);
ptag->ctrl_data2_hi = 0;
return skb;
}
static struct sk_buff *a5psw_tag_rcv(struct sk_buff *skb,
struct net_device *dev)
{
struct a5psw_tag *tag;
int port;
if (unlikely(!pskb_may_pull(skb, A5PSW_TAG_LEN))) {
dev_warn_ratelimited(&dev->dev,
"Dropping packet, cannot pull\n");
return NULL;
}
tag = dsa_etype_header_pos_rx(skb);
if (tag->ctrl_tag != htons(ETH_P_DSA_A5PSW)) {
dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid TAG marker\n");
return NULL;
}
port = FIELD_GET(A5PSW_CTRL_DATA_PORT, ntohs(tag->ctrl_data));
skb->dev = dsa_conduit_find_user(dev, 0, port);
if (!skb->dev)
return NULL;
skb_pull_rcsum(skb, A5PSW_TAG_LEN);
dsa_strip_etype_header(skb, A5PSW_TAG_LEN);
dsa_default_offload_fwd_mark(skb);
return skb;
}
static const struct dsa_device_ops a5psw_netdev_ops = {
.name = A5PSW_NAME,
.proto = DSA_TAG_PROTO_RZN1_A5PSW,
.xmit = a5psw_tag_xmit,
.rcv = a5psw_tag_rcv,
.needed_headroom = A5PSW_TAG_LEN,
};
MODULE_DESCRIPTION("DSA tag driver for Renesas RZ/N1 A5PSW switch");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_A5PSW, A5PSW_NAME);
module_dsa_tag_driver(a5psw_netdev_ops);
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