[PATCH net-next v2 3/3] net: dsa: b53: support legacy FCS tags

Álvaro Fernández Rojas posted 3 patches 4 months ago
[PATCH net-next v2 3/3] net: dsa: b53: support legacy FCS tags
Posted by Álvaro Fernández Rojas 4 months ago
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.

Fixes: 46c5176c586c ("net: dsa: b53: support legacy tags")
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 drivers/net/dsa/b53/Kconfig      | 1 +
 drivers/net/dsa/b53/b53_common.c | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

 v2: no changes

diff --git a/drivers/net/dsa/b53/Kconfig b/drivers/net/dsa/b53/Kconfig
index ebaa4a80d5444..915008e8eff53 100644
--- 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
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 862bdccb74397..222107223d109 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2245,8 +2245,11 @@ enum dsa_tag_protocol b53_get_tag_protocol(struct dsa_switch *ds, int port,
 		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;
 	}
-- 
2.39.5

Re: [PATCH net-next v2 3/3] net: dsa: b53: support legacy FCS tags
Posted by Florian Fainelli 4 months ago
On 6/10/25 09:31, Álvaro Fernández Rojas wrote:
> 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.
> 
> Fixes: 46c5176c586c ("net: dsa: b53: support legacy tags")
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
-- 
Florian