From c3cf059a4d419b9c888ce7e9952fa13ba7569b61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Sat, 14 Jun 2025 09:59:49 +0200
Subject: [PATCH] net: dsa: b53: support legacy FCS tags
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Commit 46c5176c586c ("net: dsa: b53: support legacy tags") introduced
support for legacy tags, but it turns out that BCM5325 and BCM5365
switches require the original FCS value and length, so they have to be
treated differently.

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://patch.msgid.link/20250614080000.1884236-4-noltari@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/dsa/b53/Kconfig      | 1 +
 drivers/net/dsa/b53/b53_common.c | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/net/dsa/b53/Kconfig
+++ b/drivers/net/dsa/b53/Kconfig
@@ -5,6 +5,7 @@ menuconfig B53
 	select NET_DSA_TAG_NONE
 	select NET_DSA_TAG_BRCM
 	select NET_DSA_TAG_BRCM_LEGACY
+	select NET_DSA_TAG_BRCM_LEGACY_FCS
 	select NET_DSA_TAG_BRCM_PREPEND
 	help
 	  This driver adds support for Broadcom managed switch chips. It supports
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2241,8 +2241,11 @@ enum dsa_tag_protocol b53_get_tag_protoc
 		goto out;
 	}
 
-	/* Older models require a different 6 byte tag */
-	if (is5325(dev) || is5365(dev) || is63xx(dev)) {
+	/* Older models require different 6 byte tags */
+	if (is5325(dev) || is5365(dev)) {
+		dev->tag_protocol = DSA_TAG_PROTO_BRCM_LEGACY_FCS;
+		goto out;
+	} else if (is63xx(dev)) {
 		dev->tag_protocol = DSA_TAG_PROTO_BRCM_LEGACY;
 		goto out;
 	}
