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![Vladimir Oltean](/assets/img/avatar_default.png)
Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. This one is interesting, the DSA tag is 8 bytes on RX and 4 bytes on TX. Because DSA is unaware of asymmetrical tag lengths, the overhead/needed headroom is declared as 8 bytes and therefore 4 bytes larger than it needs to be. If this becomes a problem, and the GSWIP driver can't be converted to a uniform header length, we might need to make DSA aware of separate RX/TX overhead values. Cc: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Intel / Lantiq GSWIP V2.0 PMAC tag support
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*
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* Copyright (C) 2017 - 2018 Hauke Mehrtens <hauke@hauke-m.de>
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*/
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#include <linux/bitops.h>
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#include <linux/etherdevice.h>
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#include <linux/skbuff.h>
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#include <net/dsa.h>
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#include "dsa_priv.h"
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#define GSWIP_TX_HEADER_LEN 4
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/* special tag in TX path header */
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/* Byte 0 */
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#define GSWIP_TX_SLPID_SHIFT 0 /* source port ID */
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#define GSWIP_TX_SLPID_CPU 2
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#define GSWIP_TX_SLPID_APP1 3
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#define GSWIP_TX_SLPID_APP2 4
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#define GSWIP_TX_SLPID_APP3 5
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#define GSWIP_TX_SLPID_APP4 6
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#define GSWIP_TX_SLPID_APP5 7
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/* Byte 1 */
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#define GSWIP_TX_CRCGEN_DIS BIT(7)
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#define GSWIP_TX_DPID_SHIFT 0 /* destination group ID */
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#define GSWIP_TX_DPID_ELAN 0
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#define GSWIP_TX_DPID_EWAN 1
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#define GSWIP_TX_DPID_CPU 2
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#define GSWIP_TX_DPID_APP1 3
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#define GSWIP_TX_DPID_APP2 4
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#define GSWIP_TX_DPID_APP3 5
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#define GSWIP_TX_DPID_APP4 6
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#define GSWIP_TX_DPID_APP5 7
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/* Byte 2 */
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#define GSWIP_TX_PORT_MAP_EN BIT(7)
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#define GSWIP_TX_PORT_MAP_SEL BIT(6)
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#define GSWIP_TX_LRN_DIS BIT(5)
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#define GSWIP_TX_CLASS_EN BIT(4)
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#define GSWIP_TX_CLASS_SHIFT 0
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#define GSWIP_TX_CLASS_MASK GENMASK(3, 0)
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/* Byte 3 */
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#define GSWIP_TX_DPID_EN BIT(0)
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#define GSWIP_TX_PORT_MAP_SHIFT 1
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#define GSWIP_TX_PORT_MAP_MASK GENMASK(6, 1)
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#define GSWIP_RX_HEADER_LEN 8
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/* special tag in RX path header */
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/* Byte 7 */
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#define GSWIP_RX_SPPID_SHIFT 4
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#define GSWIP_RX_SPPID_MASK GENMASK(6, 4)
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static struct sk_buff *gswip_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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u8 *gswip_tag;
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skb_push(skb, GSWIP_TX_HEADER_LEN);
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gswip_tag = skb->data;
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gswip_tag[0] = GSWIP_TX_SLPID_CPU;
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gswip_tag[1] = GSWIP_TX_DPID_ELAN;
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gswip_tag[2] = GSWIP_TX_PORT_MAP_EN | GSWIP_TX_PORT_MAP_SEL;
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gswip_tag[3] = BIT(dp->index + GSWIP_TX_PORT_MAP_SHIFT) & GSWIP_TX_PORT_MAP_MASK;
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gswip_tag[3] |= GSWIP_TX_DPID_EN;
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return skb;
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}
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static struct sk_buff *gswip_tag_rcv(struct sk_buff *skb,
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struct net_device *dev,
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struct packet_type *pt)
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{
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int port;
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u8 *gswip_tag;
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if (unlikely(!pskb_may_pull(skb, GSWIP_RX_HEADER_LEN)))
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return NULL;
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gswip_tag = skb->data - ETH_HLEN;
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/* Get source port information */
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port = (gswip_tag[7] & GSWIP_RX_SPPID_MASK) >> GSWIP_RX_SPPID_SHIFT;
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skb->dev = dsa_master_find_slave(dev, 0, port);
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if (!skb->dev)
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return NULL;
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/* remove GSWIP tag */
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skb_pull_rcsum(skb, GSWIP_RX_HEADER_LEN);
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return skb;
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}
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static const struct dsa_device_ops gswip_netdev_ops = {
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.name = "gswip",
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.proto = DSA_TAG_PROTO_GSWIP,
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.xmit = gswip_tag_xmit,
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.rcv = gswip_tag_rcv,
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.overhead = GSWIP_RX_HEADER_LEN,
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};
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_GSWIP);
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module_dsa_tag_driver(gswip_netdev_ops);
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