Re: [PATCH net-next v25 06/10] net: dsa: tag_mtk: add Airoha variant usage of this TAG

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] net: dsa: airoha/mtk eth: hardware offload broken for AIROHA tag protocol
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commit feed6f0245d293aabba2178225f4097258a1d66c
Author: Christian Marangi <ansuelsmth@gmail.com>

net: dsa: tag_mtk: add Airoha variant usage of this TAG

This commit adds a new DSA tag protocol variant for Airoha switches,
updating the Mediatek tag driver, Kconfig, and Makefile. It also adds
comments explaining the differences between Airoha AN8855 and the Mediatek
tag bitmap.

> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index 5d12191b6f6f5..9824c63ad50b3 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
[ ... ]
> @@ -76,6 +77,7 @@ enum dsa_tag_protocol {
>  	DSA_TAG_PROTO_KSZ9893		= DSA_TAG_PROTO_KSZ9893_VALUE,
>  	DSA_TAG_PROTO_LAN9303		= DSA_TAG_PROTO_LAN9303_VALUE,
>  	DSA_TAG_PROTO_MTK		= DSA_TAG_PROTO_MTK_VALUE,
> +	DSA_TAG_PROTO_AIROHA		= DSA_TAG_PROTO_AIROHA_VALUE,

[Severity: High]
Does adding this new protocol ID require updating the ethernet MAC and PPE
drivers to recognize it as well?

For example, looking at airoha_get_dsa_tag() in
drivers/net/ethernet/airoha/airoha_eth.c:

	if (dev->dsa_ptr->tag_ops->proto != DSA_TAG_PROTO_MTK)
		return 0;

And mtk_uses_dsa() in drivers/net/ethernet/mediatek/mtk_eth_soc.c:

	return netdev_uses_dsa(dev) &&
	       dev->dsa_ptr->tag_ops->proto == DSA_TAG_PROTO_MTK;

If these are not updated to also accept DSA_TAG_PROTO_AIROHA, will hardware
tag extraction and PPE hardware flow offloading (like in __mtk_ppe_check_skb()
and mtk_flow_get_dsa_port()) fail because the strict protocol checks against
DSA_TAG_PROTO_MTK no longer match?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261009161102.38961-1-ansuelsmth@gmail.com?part=6