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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/dsa/tag_rtl4_a.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/dsa/tag_rtl4_a.c')
-rw-r--r-- | net/dsa/tag_rtl4_a.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c new file mode 100644 index 000000000..6d928ee3e --- /dev/null +++ b/net/dsa/tag_rtl4_a.c @@ -0,0 +1,124 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Handler for Realtek 4 byte DSA switch tags + * Currently only supports protocol "A" found in RTL8366RB + * Copyright (c) 2020 Linus Walleij <linus.walleij@linaro.org> + * + * This "proprietary tag" header looks like so: + * + * ------------------------------------------------- + * | MAC DA | MAC SA | 0x8899 | 2 bytes tag | Type | + * ------------------------------------------------- + * + * The 2 bytes tag form a 16 bit big endian word. The exact + * meaning has been guessed from packet dumps from ingress + * frames. + */ + +#include <linux/etherdevice.h> +#include <linux/bits.h> + +#include "dsa_priv.h" + +#define RTL4_A_HDR_LEN 4 +#define RTL4_A_ETHERTYPE 0x8899 +#define RTL4_A_PROTOCOL_SHIFT 12 +/* + * 0x1 = Realtek Remote Control protocol (RRCP) + * 0x2/0x3 seems to be used for loopback testing + * 0x9 = RTL8306 DSA protocol + * 0xa = RTL8366RB DSA protocol + */ +#define RTL4_A_PROTOCOL_RTL8366RB 0xa + +static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct dsa_port *dp = dsa_slave_to_port(dev); + __be16 *p; + u8 *tag; + u16 out; + + /* Pad out to at least 60 bytes */ + if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false))) + return NULL; + + netdev_dbg(dev, "add realtek tag to package to port %d\n", + dp->index); + skb_push(skb, RTL4_A_HDR_LEN); + + dsa_alloc_etype_header(skb, RTL4_A_HDR_LEN); + tag = dsa_etype_header_pos_tx(skb); + + /* Set Ethertype */ + p = (__be16 *)tag; + *p = htons(RTL4_A_ETHERTYPE); + + out = (RTL4_A_PROTOCOL_RTL8366RB << RTL4_A_PROTOCOL_SHIFT); + /* The lower bits indicate the port number */ + out |= BIT(dp->index); + + p = (__be16 *)(tag + 2); + *p = htons(out); + + return skb; +} + +static struct sk_buff *rtl4a_tag_rcv(struct sk_buff *skb, + struct net_device *dev) +{ + u16 protport; + __be16 *p; + u16 etype; + u8 *tag; + u8 prot; + u8 port; + + if (unlikely(!pskb_may_pull(skb, RTL4_A_HDR_LEN))) + return NULL; + + tag = dsa_etype_header_pos_rx(skb); + p = (__be16 *)tag; + etype = ntohs(*p); + if (etype != RTL4_A_ETHERTYPE) { + /* Not custom, just pass through */ + netdev_dbg(dev, "non-realtek ethertype 0x%04x\n", etype); + return skb; + } + p = (__be16 *)(tag + 2); + protport = ntohs(*p); + /* The 4 upper bits are the protocol */ + prot = (protport >> RTL4_A_PROTOCOL_SHIFT) & 0x0f; + if (prot != RTL4_A_PROTOCOL_RTL8366RB) { + netdev_err(dev, "unknown realtek protocol 0x%01x\n", prot); + return NULL; + } + port = protport & 0xff; + + skb->dev = dsa_master_find_slave(dev, 0, port); + if (!skb->dev) { + netdev_dbg(dev, "could not find slave for port %d\n", port); + return NULL; + } + + /* Remove RTL4 tag and recalculate checksum */ + skb_pull_rcsum(skb, RTL4_A_HDR_LEN); + + dsa_strip_etype_header(skb, RTL4_A_HDR_LEN); + + dsa_default_offload_fwd_mark(skb); + + return skb; +} + +static const struct dsa_device_ops rtl4a_netdev_ops = { + .name = "rtl4a", + .proto = DSA_TAG_PROTO_RTL4_A, + .xmit = rtl4a_tag_xmit, + .rcv = rtl4a_tag_rcv, + .needed_headroom = RTL4_A_HDR_LEN, +}; +module_dsa_tag_driver(rtl4a_netdev_ops); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL4_A); |