From: Vladimir Oltean <email@example.com> To: Russell King - ARM Linux admin <firstname.lastname@example.org> Cc: Andrew Lunn <email@example.com>, Florian Fainelli <firstname.lastname@example.org>, Heiner Kallweit <email@example.com>, "David S. Miller" <firstname.lastname@example.org>, netdev <email@example.com> Subject: Re: [PATCH net-next 4/5] net: phylink: pcs: add 802.3 clause 22 helpers Date: Thu, 12 Mar 2020 15:35:49 +0200 [thread overview] Message-ID: <CA+h21hoOpiz6bEh7ZvZ1b7pQMbkW5-u1ZYt+Z2M32kOdA+pOfirstname.lastname@example.org> (raw) In-Reply-To: <20200312131326.GA25745@shell.armlinux.org.uk> On Thu, 12 Mar 2020 at 15:13, Russell King - ARM Linux admin <email@example.com> wrote: > > On Thu, Mar 12, 2020 at 02:54:55PM +0200, Vladimir Oltean wrote: > > On Wed, 11 Mar 2020 at 22:32, Russell King - ARM Linux admin > > <firstname.lastname@example.org> wrote: > > > > > > On Wed, Mar 11, 2020 at 09:59:18PM +0200, Vladimir Oltean wrote: > > > > On Wed, 11 Mar 2020 at 21:32, Russell King - ARM Linux admin > > > > <email@example.com> wrote: > > > > > So, why abuse some other subsystem's datastructure for something that > > > > > is entirely separate, potentially making the maintanence of that > > > > > subsystem more difficult for the maintainers? I don't get why one > > > > > would think this is an acceptable approach. > > > > > > > > > > What you've said is that you want to use struct phy_device, but you > > > > > don't want to publish it into the device model, you don't want to > > > > > use mdio accesses, you don't want to use phylib helpers. So, what's > > > > > the point of using struct phy_device? I don't see _any_ reason to > > > > > do that and make things unnecessarily more difficult for the phylib > > > > > maintainers. > > > > > > > > > > > > > So if it's such a big mistake... > > > > > > > > > > > Sorry, but you need to explain better what you would like to see here. > > > > > > > The additions I'm adding are to the SGMII specification; I find your > > > > > > > existing definitions to be obscure because they conflate two different > > > > > > > bit fields together to produce something for the ethtool linkmodes > > > > > > > (which I think is a big mistake.) > > > > > > > > > > > > I'm saying that there were already LPA_SGMII definitions in there. > > > > > > There are 2 "generic" solutions proposed now and yet they cannot agree > > > > > > on config_reg definitions. Omitting the fact that you did have a > > > > > > chance to point out that big mistake before it got merged, I'm > > > > > > wondering why you didn't remove them and add your new ones instead. > > > > > > The code rework is minimal. Is it because the definitions are in UAPI? > > > > > > If so, isn't it an even bigger mistake to put more stuff in UAPI? Why > > > > > > would user space care about the SGMII config_reg? There's no user even > > > > > > of the previous SGMII definitions as far as I can tell. > > > > > > > > > > I don't see it as a big deal - certainly not the kind of fuss you're > > > > > making over it. > > > > > > > > > > > > > ...why keep it? > > > > I'm all for creating a common interface for configuring this. It just > > > > makes me wonder how common it is going to be, if there's already a > > > > driver in-tree, from the same PCS hardware vendor, which after the > > > > patchset you're proposing is still going to use a different > > > > infrastructure. > > > > > > Do you see any reason why felix_vsc9959 couldn't make use of the code > > > I'm proposing? > > > > > > > No. But the intentions just from reading the cover letter and the > > patches seemed a bit unclear. The fact that there are no proposed > > users in this series, and that in your private cex7 branch only dpaa2 > > uses it, it seemed to me that at least some clarification was due. > > I have no further comments. The patches themselves are fairly trivial. > > I have been told by Andrew to send small series, so that's what I do. > > I have not included the DPAA2 changes in this series because it was > not ready for submission - I had to initially hard-code the physical > addresses of the MDIO blocks, but I've later moved to describing them > in the DTS, which now brings with it additional complexities since > (a) existing DTS need to continue working and (b) working out how to > submit those changes since the DTS changes and the net changes should > go via different paths, and ensuring that no breakage will occur > should they become separated. > I think even asking for firmware ABI changes in MC is worth a shot? It might be preferable to get away with the firmware giving you the PCS base address for a DPMAC rather than getting it from DT, for the reasons that you've mentioned. Or even asking for ABI for the firmware to perform the MDIO read/write itself. > If you look at the branches that I publish, you will notice that they > are based on v5.5, and so do not contain your changes to felix_vsc9959 > that you have been talking about, so felix_vsc9959 is not yet on my > radar. > Yes, I noticed. > However, it seems we take different approaches to contributing code to > the kernel; I look to see whether there is value to providing common > infrastructure and then provide it, whereas you seem to take the > approach of writing specific drivers and hope that someone else spots > the code in your driver and converts it to something generic. I > disagree with your approach because it's been well proven over the > years that the kernel has been around that relying on others to spot > code that could be refactored into common helpers just doesn't happen. > Yes, it happens but only occasionally, and not always when common > helpers get introduced. > > You have already proven the worth of having a set of common helpers - > it seems that felix_vsc9959 and DPAA2 can both make use of these, > which does not surprise me one bit, since these helpers are only > implementing what is published in industry standards or defacto > industry standards - and as such are likely to be implemented by a lot > of vendors. Sure, there will be exceptions and augmentations, which > is something I considered when creating these common helpers. That's > why they are helpers rather than being mandatory implementations. > Nothing wrong with that. I'm willing to try to rework felix using these helpers, but I just don't have the time right now. That and DPAA2 make it look like it may take a while for the first users to come... Apologies in advance if there are other immediate potential users which are not on my radar. > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up -Vladimir
next prev parent reply other threads:[~2020-03-12 13:36 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-11 12:06 [PATCH net-next 0/5] add phylink support for PCS Russell King - ARM Linux admin 2020-03-11 12:07 ` [PATCH net-next 1/5] net: mii: convert mii_lpa_to_ethtool_lpa_x() to linkmode variant Russell King 2020-03-11 12:07 ` [PATCH net-next 2/5] net: mii: add linkmode_adv_to_mii_adv_x() Russell King 2020-03-11 12:07 ` [PATCH net-next 3/5] net: mdiobus: add APIs for modifying a MDIO device register Russell King 2020-03-11 12:07 ` [PATCH net-next 4/5] net: phylink: pcs: add 802.3 clause 22 helpers Russell King 2020-03-11 14:06 ` Vladimir Oltean 2020-03-11 17:09 ` Russell King - ARM Linux admin 2020-03-11 18:44 ` Vladimir Oltean 2020-03-11 19:32 ` Russell King - ARM Linux admin 2020-03-11 19:59 ` Vladimir Oltean 2020-03-11 20:32 ` Russell King - ARM Linux admin 2020-03-12 12:54 ` Vladimir Oltean 2020-03-12 13:13 ` Russell King - ARM Linux admin 2020-03-12 13:35 ` Vladimir Oltean [this message] 2020-03-11 12:07 ` [PATCH net-next 5/5] net: phylink: pcs: add 802.3 clause 45 helpers Russell King 2020-03-11 12:46 ` [PATCH net-next 0/5] add phylink support for PCS Vladimir Oltean 2020-03-11 12:54 ` Russell King - ARM Linux admin 2020-03-11 13:57 ` Vladimir Oltean 2020-03-11 17:05 ` Russell King - ARM Linux admin 2020-03-11 18:16 ` Vladimir Oltean
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