Messages in this thread |  | | Subject | Re: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for platforms without PHY" | From | Robin Murphy <> | Date | Tue, 7 Jan 2020 12:36:21 +0000 |
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On 07/01/2020 12:14 pm, Sriram Dash wrote: >> From: Robin Murphy <robin.murphy@arm.com> >> Subject: Re: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for >> platforms without PHY" >> >> On 07/01/2020 5:46 am, Sriram Dash wrote: >>>> From: Florian Fainelli <f.fainelli@gmail.com> >>>> Subject: [PATCH net] Revert "net: stmmac: platform: Fix MDIO init for >>> platforms >>>> without PHY" >>>> >>>> This reverts commit d3e014ec7d5ebe9644b5486bc530b91e62bbf624 ("net: >>>> stmmac: platform: Fix MDIO init for platforms without PHY") because >>>> it >>> breaks >>>> existing systems with stmmac which do not have a MDIO bus sub-node >>>> nor a 'phy-handle' property declared in their Device Tree. On those >>>> systems, the stmmac MDIO bus is expected to be created and then >>>> scanned by >>>> of_mdiobus_register() to create PHY devices. >>>> >>>> While these systems should arguably make use of a more accurate >>>> Device >>> Tree >>>> reprensentation with the use of the MDIO bus sub-node an appropriate >>>> 'phy- handle', we cannot break them, therefore restore the behavior >>>> prior to the >>> said >>>> commit. >>>> >>>> Fixes: d3e014ec7d5e ("net: stmmac: platform: Fix MDIO init for >>>> platforms without PHY") >>>> Reported-by: Heiko Stuebner <heiko@sntech.de> >>>> Reported-by: kernelci.org bot <bot@kernelci.org> >>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> >>> Nacked-by: Sriram Dash <Sriram.dash@samsung.com> >>> >>>> --- >>>> Heiko, >>>> >>>> I did not add the Tested-by because the patch is a little bit >>>> different >>> from what >>>> you tested, even if you most likely were not hitting the other part >>>> that I >>> was >>>> changing. Thanks! >>>> >>>> drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> index cc8d7e7bf9ac..bedaff0c13bd 100644 >>>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> @@ -320,7 +320,7 @@ static int stmmac_mtl_setup(struct >>>> platform_device *pdev, static int stmmac_dt_phy(struct >> plat_stmmacenet_data *plat, >>>> struct device_node *np, struct device *dev) { >>>> - bool mdio = false; >>>> + bool mdio = true; >>> >>> >>> This is breaking for the platforms with fixed-link. >>> stih418-b2199.dts and 169445.dts to name a few. >>> >>> For the newer platforms, they should provide the mdio/ snps,dwmac-mdio >>> property in the device tree as we are checking the mdio/ >>> snps,dwmac-mdio property in the stmmac_platform driver for the mdio bus >> memory allocation. >>> For existing platforms, I agree we should not break them, but we >>> should make the code correct. And make the existing platforms adapt to the >> proper code. >>> There is a proposed solution. >>> https://protect2.fireeye.com/url?k=d075c0fc-8da69942-d0744bb3-0cc47a31 >>> ba82-60be9f5a0fb38a27&u=https://lkml.org/lkml/2020/1/7/14 >>> >>> What do you think? >> >> The binding says that the phy handle and mdio child node are optional, so >> "update all of the DTBs!" is not a viable solution. I'm far from an expert here, but > > I get your point Robin. Because the mdio child or snps,dwmac-mdio is not mandatory, > there has been this problem. > >> AFAICS the fault of the current code is that it assumes the lack of a phy handle >> implies a fixed link, so the obvious answer is to actually check whether the > > Kind of. > >> "fixed-link" property is present. > > > I agree to have a fixed link check. Possibly this can be done:
FWIW, given the 4th case in the kerneldoc table I think this check might need to come first. On the upside, there appears to be a handy helper already, so it may just be as simple as:
bool mdio = !of_phy_is_fixed_link(np);
Robin.
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c > @@ -320,7 +320,9 @@ static int stmmac_mtl_setup(struct platform_device *pdev, > static int stmmac_dt_phy(struct plat_stmmacenet_data *plat, > struct device_node *np, struct device *dev) > { > - bool mdio = false; > + bool mdio = true; > + struct device_node *fixed_link; > + > static const struct of_device_id need_mdio_ids[] = { > { .compatible = "snps,dwc-qos-ethernet-4.10" }, > {}, > @@ -340,9 +342,8 @@ static int stmmac_dt_phy(struct plat_stmmacenet_data *plat, > } > } > > - if (plat->mdio_node) { > - dev_dbg(dev, "Found MDIO subnode\n"); > - mdio = true; > + if (of_get_child_by_name(np, "fixed-link")) { > + mdio = false; > } > > if (mdio) { > > Neil and Heiko, > > Can you guys please test this on your platforms? > We can post a more cleaner version of the patch if all agree to it. > >> >> Robin. >> >>> >>>> static const struct of_device_id need_mdio_ids[] = { >>>> { .compatible = "snps,dwc-qos-ethernet-4.10" }, >>>> {}, >>>> -- >>>> 2.19.1 >>> >>> >>> >>> _______________________________________________ >>> linux-arm-kernel mailing list >>> linux-arm-kernel@lists.infradead.org >>> https://protect2.fireeye.com/url?k=2cb95551-716a0cef-2cb8de1e-0cc47a31 >>> ba82-d01ceb62a8a93fa2&u=http://lists.infradead.org/mailman/listinfo/li >>> nux-arm-kernel >>> >
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