[PATCH net v4 5/7] net: dsa: mt7530: fix handling of LLDP frames

Russell King (Oracle) linux at armlinux.org.uk
Wed Jun 14 09:42:26 PDT 2023


On Mon, Jun 12, 2023 at 10:59:43AM +0300, arinc9.unal at gmail.com wrote:
> From: Arınç ÜNAL <arinc.unal at arinc9.com>
> 
> LLDP frames are link-local frames, therefore they must be trapped to the
> CPU port. Currently, the MT753X switches treat LLDP frames as regular
> multicast frames, therefore flooding them to user ports. To fix this, set
> LLDP frames to be trapped to the CPU port(s).
> 
> The mt753x_bpdu_port_fw enum is universally used for trapping frames,
> therefore rename it and the values in it to mt753x_port_fw.
> 
> For MT7530, LLDP frames received from a user port will be trapped to the
> numerically smallest CPU port which is affine to the DSA conduit interface
> that is up.
> 
> For MT7531 and the switch on the MT7988 SoC, LLDP frames received from a
> user port will be trapped to the CPU port that is affine to the user port
> from which the frames are received.
> 
> The bit for R0E_MANG_FR is 27. When set, the switch regards the frames with
> :0E MAC DA as management (LLDP) frames. This bit is set to 1 after reset on
> MT7530 and MT7531 according to the documents MT7620 Programming Guide v1.0
> and MT7531 Reference Manual for Development Board v1.0, so there's no need
> to deal with this bit. Since there's currently no public document for the
> switch on the MT7988 SoC, I assume this is also the case for this switch.
> 
> Fixes: b8f126a8d543 ("net-next: dsa: add dsa support for Mediatek MT7530 switch")

Patch 4 claims to be a fix for this commit, and introduces one of these
modifications to MT753X_BPC, which this patch then changes.

On the face of it, it seems this patch is actually a fix to patch 4 as
well as the original patch, so does that mean that patch 4 only half
fixes a problem?

Bah, I give up with this. IMHO it's just too much of a mess trying to
do any sane review of it. No, I'm not going to give any acks or
reviewed-bys to it because nothing here makes much sense to me.

And I just can't be bothered trying to parse the commit messages
anymore.

Sorry but no, I'm going to be ignoring these patch sets from now on.

-- 
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