Re: [RFC net-next v3 5/6] net: phy: nxp-c45-tja11xx: add MACsec statistics

[Radu Pirea (OSS)]

On 11.09.2023 15:00, Sabrina Dubroca wrote:
> 2023-09-06, 19:01:33 +0300, Radu Pirea (NXP OSS) wrote:
> > +
> > +	nxp_c45_macsec_read(phydev, MACSEC_OPUS, &reg);
> > +	dev_stats->OutPktsUntagged = reg;
>
> Can you read directly into OutPktsUntagged? It would make the code a
> little bit more readable.
>
> It's a bit unfortunate that all those stats read turn into 2 (or 4 for
> the 64b counters) reads. If the HW's value can be incremented while
> we're reading it we'll see an inconsistent value :(

The 32b reads are consistent. The inconsistency may appear when the 
lower half of a 64b register overflows.

> > +
> > +	nxp_c45_macsec_read(phydev, MACSEC_OOE1HS, &reg);
> > +	stats->OutOctetsEncrypted = (u64)reg << 32;
> > +	nxp_c45_macsec_read(phydev, MACSEC_OOE2HS, &reg);
> > +	stats->OutOctetsEncrypted |= reg;
>
> Since you have a few 64b HW counters, I'd suggest a helper:
>
> stats->OutOctetsEncrypted = nxp_c45_macsec_read64(phydev, MACSEC_OOE1HS, MACSEC_OOE2HS);
>
>
> Or (more consistent with the 32b reads):
>
> nxp_c45_macsec_read64(phydev, MACSEC_OOE1HS, MACSEC_OOE2HS, &stats->OutOctetsEncrypted);

I will add two helper:
- nxp_c45_macsec_read32_64	- read 32bit counter into u64
- nxp_c45_macsec_read64		- read 64bit counter into u64

--
Radu P.