netdev - Re: [PATCH net-next 2/4] net: altera-tse: Read core revision before registering netdev

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Message-ID: <08518010-3997-4e11-b17e-94765e9c1ca9@bootlin.com>
Date: Fri, 31 Oct 2025 17:32:49 +0100
From: Maxime Chevallier <maxime.chevallier@...tlin.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, davem@...emloft.net,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Russell King <linux@...linux.org.uk>,
 Simon Horman <horms@...nel.org>, Boon Khai Ng <boon.khai.ng@...era.com>,
 Alexis Lothoré <alexis.lothore@...tlin.com>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, netdev@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next 2/4] net: altera-tse: Read core revision before
 registering netdev

Hi Andrew,

On 31/10/2025 17:15, Andrew Lunn wrote:
> On Thu, Oct 30, 2025 at 11:24:15AM +0100, Maxime Chevallier wrote:
>> The core revision is used in .ndo_open(), so we have to populate it
>> before regstering the netdev.
> 
> All that open does is:
> 
> 	if ((priv->revision < 0xd00) || (priv->revision > 0xe00))
> 		netdev_warn(dev, "TSE revision %x\n", priv->revision);
> 
> So i agree this does not need a Fixes: tag.
> 
> But i do wounder why this is in open. The revision has already been
> printed once in probe. Are values < 0xd00 or > 0xe00 significant? Is
> this left over code and some actions that were previously here are now
> gone?
> 
> Maybe a better fix is to remove this, and make revision local in
> probe?

You are correct. I was focusing on leaving the existing behaviour
untouched so I didn't dig any further, but now that you point this
out, we can definitely simplify that.

The revision is read from the priv->megacore_revsion address, and
stored into priv->revision.

The only other spot where this could have been useful is in
altera_tse_ethtool.c, .tse_get_drvinfo(), but here we actually
re-read the version from the registers...

So indeed we can keep that local to probe, print a warning for
unexpected version, and just drop priv->revision :)

Thanks, I'll respin with this.

Maxime

>       Andrew