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339133f6c3
This drops the code setting bit 9 on egress frames on the Realtek "type A" (RTL8366RB) frames. This bit was set on ingress frames for unknown reason, and was set on egress frames as the format of ingress and egress frames was believed to be the same. As that assumption turned out to be false, and since this bit seems to have zero effect on the behaviour of the switch let's drop this bit entirely. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Link: https://lore.kernel.org/r/20210913143156.1264570-1-linus.walleij@linaro.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
124 lines
3 KiB
C
124 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Handler for Realtek 4 byte DSA switch tags
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* Currently only supports protocol "A" found in RTL8366RB
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* Copyright (c) 2020 Linus Walleij <linus.walleij@linaro.org>
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*
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* This "proprietary tag" header looks like so:
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*
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* -------------------------------------------------
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* | MAC DA | MAC SA | 0x8899 | 2 bytes tag | Type |
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* -------------------------------------------------
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*
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* The 2 bytes tag form a 16 bit big endian word. The exact
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* meaning has been guessed from packet dumps from ingress
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* frames.
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*/
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#include <linux/etherdevice.h>
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#include <linux/bits.h>
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#include "dsa_priv.h"
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#define RTL4_A_HDR_LEN 4
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#define RTL4_A_ETHERTYPE 0x8899
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#define RTL4_A_PROTOCOL_SHIFT 12
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/*
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* 0x1 = Realtek Remote Control protocol (RRCP)
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* 0x2/0x3 seems to be used for loopback testing
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* 0x9 = RTL8306 DSA protocol
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* 0xa = RTL8366RB DSA protocol
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*/
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#define RTL4_A_PROTOCOL_RTL8366RB 0xa
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static struct sk_buff *rtl4a_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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__be16 *p;
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u8 *tag;
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u16 out;
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/* Pad out to at least 60 bytes */
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if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false)))
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return NULL;
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netdev_dbg(dev, "add realtek tag to package to port %d\n",
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dp->index);
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skb_push(skb, RTL4_A_HDR_LEN);
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dsa_alloc_etype_header(skb, RTL4_A_HDR_LEN);
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tag = dsa_etype_header_pos_tx(skb);
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/* Set Ethertype */
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p = (__be16 *)tag;
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*p = htons(RTL4_A_ETHERTYPE);
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out = (RTL4_A_PROTOCOL_RTL8366RB << RTL4_A_PROTOCOL_SHIFT);
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/* The lower bits indicate the port number */
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out |= BIT(dp->index);
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p = (__be16 *)(tag + 2);
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*p = htons(out);
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return skb;
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}
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static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb,
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struct net_device *dev)
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{
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u16 protport;
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__be16 *p;
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u16 etype;
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u8 *tag;
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u8 prot;
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u8 port;
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if (unlikely(!pskb_may_pull(skb, RTL4_A_HDR_LEN)))
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return NULL;
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tag = dsa_etype_header_pos_rx(skb);
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p = (__be16 *)tag;
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etype = ntohs(*p);
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if (etype != RTL4_A_ETHERTYPE) {
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/* Not custom, just pass through */
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netdev_dbg(dev, "non-realtek ethertype 0x%04x\n", etype);
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return skb;
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}
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p = (__be16 *)(tag + 2);
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protport = ntohs(*p);
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/* The 4 upper bits are the protocol */
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prot = (protport >> RTL4_A_PROTOCOL_SHIFT) & 0x0f;
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if (prot != RTL4_A_PROTOCOL_RTL8366RB) {
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netdev_err(dev, "unknown realtek protocol 0x%01x\n", prot);
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return NULL;
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}
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port = protport & 0xff;
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skb->dev = dsa_master_find_slave(dev, 0, port);
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if (!skb->dev) {
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netdev_dbg(dev, "could not find slave for port %d\n", port);
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return NULL;
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}
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/* Remove RTL4 tag and recalculate checksum */
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skb_pull_rcsum(skb, RTL4_A_HDR_LEN);
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dsa_strip_etype_header(skb, RTL4_A_HDR_LEN);
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dsa_default_offload_fwd_mark(skb);
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return skb;
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}
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static const struct dsa_device_ops rtl4a_netdev_ops = {
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.name = "rtl4a",
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.proto = DSA_TAG_PROTO_RTL4_A,
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.xmit = rtl4a_tag_xmit,
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.rcv = rtl4a_tag_rcv,
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.needed_headroom = RTL4_A_HDR_LEN,
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};
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module_dsa_tag_driver(rtl4a_netdev_ops);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL4_A);
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