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4e50025129
Some really really weird switches just couldn't decide whether to use a normal or a tail tagger, so they just did both. This creates problems for DSA, because we only have the concept of an 'overhead' which can be applied to the headroom or to the tailroom of the skb (like for example during the central TX reallocation procedure), depending on the value of bool tail_tag, but not to both. We need to generalize DSA to cater for these odd switches by transforming the 'overhead / tail_tag' pair into 'needed_headroom / needed_tailroom'. The DSA master's MTU is increased to account for both. The flow dissector code is modified such that it only calls the DSA adjustment callback if the tagger has a non-zero header length. Taggers are trivially modified to declare either needed_headroom or needed_tailroom, based on the tail_tag value that they currently declare. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2019 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
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*/
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#include <linux/bitfield.h>
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#include <linux/etherdevice.h>
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#include "dsa_priv.h"
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#define AR9331_HDR_LEN 2
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#define AR9331_HDR_VERSION 1
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#define AR9331_HDR_VERSION_MASK GENMASK(15, 14)
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#define AR9331_HDR_PRIORITY_MASK GENMASK(13, 12)
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#define AR9331_HDR_TYPE_MASK GENMASK(10, 8)
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#define AR9331_HDR_BROADCAST BIT(7)
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#define AR9331_HDR_FROM_CPU BIT(6)
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/* AR9331_HDR_RESERVED - not used or may be version field.
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* According to the AR8216 doc it should 0b10. On AR9331 it is 0b11 on RX path
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* and should be set to 0b11 to make it work.
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*/
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#define AR9331_HDR_RESERVED_MASK GENMASK(5, 4)
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#define AR9331_HDR_PORT_NUM_MASK GENMASK(3, 0)
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static struct sk_buff *ar9331_tag_xmit(struct sk_buff *skb,
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struct net_device *dev)
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{
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struct dsa_port *dp = dsa_slave_to_port(dev);
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__le16 *phdr;
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u16 hdr;
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phdr = skb_push(skb, AR9331_HDR_LEN);
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hdr = FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);
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hdr |= AR9331_HDR_FROM_CPU | dp->index;
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/* 0b10 for AR8216 and 0b11 for AR9331 */
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hdr |= AR9331_HDR_RESERVED_MASK;
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phdr[0] = cpu_to_le16(hdr);
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return skb;
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}
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static struct sk_buff *ar9331_tag_rcv(struct sk_buff *skb,
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struct net_device *ndev,
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struct packet_type *pt)
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{
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u8 ver, port;
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u16 hdr;
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if (unlikely(!pskb_may_pull(skb, AR9331_HDR_LEN)))
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return NULL;
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hdr = le16_to_cpu(*(__le16 *)skb_mac_header(skb));
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ver = FIELD_GET(AR9331_HDR_VERSION_MASK, hdr);
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if (unlikely(ver != AR9331_HDR_VERSION)) {
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netdev_warn_once(ndev, "%s:%i wrong header version 0x%2x\n",
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__func__, __LINE__, hdr);
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return NULL;
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}
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if (unlikely(hdr & AR9331_HDR_FROM_CPU)) {
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netdev_warn_once(ndev, "%s:%i packet should not be from cpu 0x%2x\n",
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__func__, __LINE__, hdr);
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return NULL;
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}
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skb_pull_rcsum(skb, AR9331_HDR_LEN);
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/* Get source port information */
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port = FIELD_GET(AR9331_HDR_PORT_NUM_MASK, hdr);
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skb->dev = dsa_master_find_slave(ndev, 0, port);
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if (!skb->dev)
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return NULL;
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return skb;
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}
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static const struct dsa_device_ops ar9331_netdev_ops = {
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.name = "ar9331",
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.proto = DSA_TAG_PROTO_AR9331,
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.xmit = ar9331_tag_xmit,
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.rcv = ar9331_tag_rcv,
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.needed_headroom = AR9331_HDR_LEN,
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};
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_AR9331);
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module_dsa_tag_driver(ar9331_netdev_ops);
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