Messages in this thread | ![/](/images/icornerl.gif) | | From | Jiangfeng Ma <> | Subject | RE: [PATCH] net:stmmac:stmmac_platform:Add snps,xpcs devicetree parsing | Date | Tue, 12 Dec 2023 13:15:06 +0000 |
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> -----Original Message----- > From: Jiangfeng Ma > Sent: Tuesday, December 12, 2023 6:51 PM > To: Serge Semin <fancer.lancer@gmail.com>; Maxime Chevallier <maxime.chevallier@bootlin.com> > Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>; Jose Abreu <joabreu@synopsys.com>; David > S. Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub Kicinski > <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Maxime Coquelin > <mcoquelin.stm32@gmail.com>; Simon Horman <horms@kernel.org>; Andrew Halaney > <ahalaney@redhat.com>; Bartosz Golaszewski <bartosz.golaszewski@linaro.org>; Shenwei Wang > <shenwei.wang@nxp.com>; Johannes Zink <j.zink@pengutronix.de>; Russell King (Oracle > <rmk+kernel@armlinux.org.uk>; Jochen Henneberg <jh@henneberg-systemdesign.com>; open > list:STMMAC ETHERNET DRIVER <netdev@vger.kernel.org>; moderated list:ARM/STM32 > ARCHITECTURE <linux-stm32@st-md-mailman.stormreply.com>; moderated list:ARM/STM32 > ARCHITECTURE <linux-arm-kernel@lists.infradead.org>; open list <linux-kernel@vger.kernel.org>; > James Li <lijames@synopsys.com>; Martin McKenny <mmckenny@synopsys.com> > Subject: Re: [PATCH] net:stmmac:stmmac_platform:Add snps,xpcs devicetree parsing > Sorry for the problem with my mail settings. > > > -----Original Message----- > > From: Serge Semin <fancer.lancer@gmail.com> > > Sent: Friday, December 8, 2023 10:28 PM > > To: Maxime Chevallier <maxime.chevallier@bootlin.com>; Jiangfeng Ma > <jiama@synopsys.com> > > Cc: Jiangfeng Ma <jiama@synopsys.com>; Alexandre Torgue <alexandre.torgue@foss.st.com>; > Jose > > Abreu <joabreu@synopsys.com>; David S. Miller <davem@davemloft.net>; Eric Dumazet > > <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; > > Maxime Coquelin <mcoquelin.stm32@gmail.com>; Simon Horman <horms@kernel.org>; Andrew > > Halaney <ahalaney@redhat.com>; Bartosz Golaszewski <bartosz.golaszewski@linaro.org>; Shenwei > > Wang <shenwei.wang@nxp.com>; Johannes Zink <j.zink@pengutronix.de>; Russell King (Oracle > > <rmk+kernel@armlinux.org.uk>; Jochen Henneberg <jh@henneberg-systemdesign.com>; open > > list:STMMAC ETHERNET DRIVER <netdev@vger.kernel.org>; moderated list:ARM/STM32 > > ARCHITECTURE <linux-stm32@st-md-mailman.stormreply.com>; moderated list:ARM/STM32 > > ARCHITECTURE <linux-arm-kernel@lists.infradead.org>; open list <linux-kernel@vger.kernel.org>; > James > > Li <lijames@synopsys.com>; Martin McKenny <mmckenny@synopsys.com> > > Subject: Re: [PATCH] net:stmmac:stmmac_platform:Add snps,xpcs devicetree parsing > > > Hi Maxime, Serge > Thanks for your review! > > > Hi Maxime, Jiangfeng > > > > On Fri, Dec 08, 2023 at 09:14:08AM +0100, Maxime Chevallier wrote: > > > Hello, > > > > > > On Fri, 8 Dec 2023 07:02:19 +0000 > > > Jiangfeng Ma <Jiangfeng.Ma@synopsys.com> wrote: > > > > > > > In order to setup xpcs, has_xpcs must be set to a non-zero value. > > > > Add new optional devicetree properties representing this. > > > > > > > > If has_xpcs is set to true, then xpcs_an_inband should preferably be > > > > consistent with it, Otherwise, some errors may occur when starting > > > > the network, For example, the phy interface that xpcs already supports, > > > > but link up fails. > > > > > > Can you elaborate on why you need this, and on which platform > > > especially ? Usually drivers for the various stmmac variants know if > > > they have XPCS or not, or can guess it based on some info such as the > > > configured PHY mode (dwmac-intel). > > There is no specific platform here. I utilize the dwmcac-generic platform, > and xpcs is utilized as the MDIO device or it can be seen as a C45 PHY. > While it's sometimes possible to deduce the presence of xpcs based on information > such as the phy mode (dwmac-intel), this is not always a definitive indicator. > For instance, the support of SGMII by XPCS doesn't imply > that all SGMII-supporting PHYs include XPCS. But as Serge mentioned, using pcs-handle, > or pcs-handle-name might be a more effective approach. > > > > > > Besides that, there are a few issues with your submission. If DT is the > > > way to go (and I don't say it is), you would also need to update the > > > bindings to document that property. > > > > > > > The types of has_xpcs and xpcs_an_inband are unsigned int, > > > > and generally used as flags. So it may be more reasonable to set them to > > > > bool type. This can also be confirmed from the type of @ovr_an_inband. > > > > > > And this part would go into a separate patch. > Sorry for this issue, I will create the patch separately later. > > > > In addition to what Maxime already said having DT-bindings adjusted to > > fit to the pattern implemented in the software part is a wrong way to > > go. The best choice in this case is to add the DW XPCS DT-node to the > > DW MAC MDIO/MI bus and then use the "pcs-handle" to inform the MAC > > (mainly it's driver) of what PCS-device is actually attached to it. > > The series I submitted on this week is exactly about that: > > https://urldefense.com/v3/__https://lore.kernel.org/netdev/20231205103559.9605-1- > fancer.lancer@g > > mail.com/__;!!A4F2R9G_pg!Y6R3WZWHeBdrkZklbqrAQARbHnQ- > g_Tbb6r5IqcsSHMQ_l4rOzLLgZvLPl6YP > > BYferbjrbjZA6_XvSSSvkV35eo2jWPz$ > > I guess I'll need about a month or so to settle all the comments, but > > the solution implemented there will be better than this one really. > > > Yes, I agree that binding the xpcs via the "pcs-handle" DT firmware node > is a better way. but the current method of binding xpcs through scanning > addresses still relies on mdio_bus_data->has_xpcs. > The 16th patch in your patchset also mentions the difficulty of > obtaining has_xpcs. Therefore, can we add parsing of pcs-handle-names > in the platform to determine if the xpcs exists, like this: > > if (plat->mdio_bus_data) { > rc = of_property_match_string(np, "pcs-handle-names", "dw-xpcs"); > if (rc >= 0) { > plat->mdio_bus_data->has_xpcs = true; > plat->mdio_bus_data->xpcs_an_inband = true; > } > } > > Thanks, > Jiangfeng > > > -Serge(y) > > > > > > > > Thanks, > > > > > > Maxime > > >
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