From: Vladimir Oltean <email@example.com> To: "Russell King (Oracle)" <firstname.lastname@example.org> Cc: Prasanna Vengateshan <email@example.com>, Andrew Lunn <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, UNGLinuxDriver@microchip.com, Woojung.Huh@microchip.com, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com Subject: Re: [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x Date: Wed, 4 Aug 2021 13:46:25 +0300 [thread overview] Message-ID: <20210804104625.d2qw3gr7algzppz5@skbuf> (raw) In-Reply-To: <20210804095954.GN22278@shell.armlinux.org.uk> On Wed, Aug 04, 2021 at 10:59:54AM +0100, Russell King (Oracle) wrote: > This is why we need to have a clear definition of what the various > RGMII interface types are, how and where they are applied, and make > sure everyone sticks to that. We have this documented in > Documentation/networking/phy.rst. The problem is that I have no clear migration path for the drivers I maintain, like sja1105, and I suspect that others might be in the exact same situation. Currently, if the sja1105 needs to add internal delays in a MAC-to-MAC (fixed-link) setup, it does that based on the phy-mode string. So "rgmii-id" + "fixed-link" means for sja1105 "add RX and TX RGMII internal delays", even though the documentation now says "the MAC should not add the RX or TX delays in this case". There are 2 cases to think about, old driver with new DT blob and new driver with old DT blob. If breakage is involved, I am not actually very interested in doing the migration, because even though the interpretation of the phy-mode string is inconsistent between the phy-handle and fixed-link case (which was deliberate), at least it currently does all that I need it to. I am not even clear what is the expected canonical behavior for a MAC driver. It parses rx-internal-delay-ps and tx-internal-delay-ps, and then what? It treats all "rgmii*" phy-mode strings identically? Or is it an error to have "rgmii-rxid" for phy-mode and non-zero rx-internal-delay-ps? If it is an error, should all MAC drivers check for it? And if it is an error, does it not make migration even more difficult (adding an rx-internal-delay-ps property to a MAC OF node which already uses "rgmii-id" would be preferable to also having to change the "rgmii-id" to "rgmii", because an old kernel might also need to work with that DT blob, and that will ignore the new rx-internal-delay-ps property). Does qca8k_setup_of_rgmii_delay(), a very recent function, even do the right thing with rx-internal-delay-ps, or is it doing the exact opposite of the right thing (it applies rx-internal-delay-ps when in rgmii-id or rgmii-rxid mode).
next prev parent reply other threads:[~2021-08-04 10:46 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-23 17:30 [PATCH v3 net-next 00/10] net: dsa: microchip: DSA driver support for LAN937x switch Prasanna Vengateshan 2021-07-23 17:30 ` [PATCH v3 net-next 01/10] dt-bindings: net: dsa: dt bindings for microchip lan937x Prasanna Vengateshan 2021-07-26 22:49 ` Rob Herring 2021-07-23 17:31 ` [PATCH v3 net-next 02/10] net: dsa: move mib->cnt_ptr reset code to ksz_common.c Prasanna Vengateshan 2021-07-23 18:53 ` Vladimir Oltean 2021-07-23 17:31 ` [PATCH v3 net-next 03/10] net: phy: Add support for LAN937x T1 phy driver Prasanna Vengateshan 2021-08-11 17:52 ` Prasanna Vengateshan 2021-07-23 17:31 ` [PATCH v3 net-next 04/10] net: dsa: tag_ksz: add tag handling for Microchip LAN937x Prasanna Vengateshan 2021-07-23 19:23 ` Vladimir Oltean 2021-07-23 17:31 ` [PATCH v3 net-next 05/10] net: dsa: microchip: add DSA support for microchip lan937x Prasanna Vengateshan 2021-07-31 15:04 ` Vladimir Oltean 2021-07-31 22:05 ` Andrew Lunn 2021-08-02 21:33 ` Vladimir Oltean 2021-08-03 14:43 ` Andrew Lunn 2021-08-03 15:05 ` Vladimir Oltean 2021-08-02 10:45 ` Prasanna Vengateshan 2021-08-02 12:15 ` Vladimir Oltean 2021-08-02 13:13 ` Andrew Lunn 2021-08-02 13:59 ` Vladimir Oltean 2021-08-02 20:47 ` Andrew Lunn 2021-08-03 16:54 ` Prasanna Vengateshan 2021-08-03 23:54 ` Vladimir Oltean 2021-08-04 9:59 ` Russell King (Oracle) 2021-08-04 10:46 ` Vladimir Oltean [this message] 2021-08-04 14:28 ` Prasanna Vengateshan 2021-08-04 14:51 ` Vladimir Oltean 2021-08-07 15:40 ` Andrew Lunn 2021-08-07 17:00 ` Vladimir Oltean 2021-08-11 17:44 ` Prasanna Vengateshan 2021-08-11 18:23 ` Andrew Lunn 2021-08-11 20:14 ` Russell King (Oracle) 2021-08-11 20:20 ` Vladimir Oltean 2021-08-11 20:22 ` Andrew Lunn 2021-07-23 17:31 ` [PATCH v3 net-next 06/10] net: dsa: microchip: add support for phylink management Prasanna Vengateshan 2021-07-31 15:27 ` Vladimir Oltean 2021-08-03 17:04 ` Prasanna Vengateshan 2021-07-23 17:31 ` [PATCH v3 net-next 07/10] net: dsa: microchip: add support for ethtool port counters Prasanna Vengateshan 2021-07-23 17:31 ` [PATCH v3 net-next 08/10] net: dsa: microchip: add support for port mirror operations Prasanna Vengateshan 2021-07-31 15:24 ` Vladimir Oltean 2021-07-23 17:31 ` [PATCH v3 net-next 09/10] net: dsa: microchip: add support for fdb and mdb management Prasanna Vengateshan 2021-07-31 15:19 ` Vladimir Oltean 2021-07-23 17:31 ` [PATCH v3 net-next 10/10] net: dsa: microchip: add support for vlan operations Prasanna Vengateshan 2021-07-31 15:08 ` Vladimir Oltean 2021-08-02 10:48 ` Prasanna Vengateshan
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