Re: [PATCH 4.19 320/639] ARM: dts: ls1021: Fix SGMII PCS link remaining down after PHY disconnect

From: Pavel Machek
Date: Sat Jan 25 2020 - 14:13:37 EST


Hi!

> [ Upstream commit c7861adbe37f576931650ad8ef805e0c47564b9a ]
>
> Each eTSEC MAC has its own TBI (SGMII) PCS and private MDIO bus.
> But due to a DTS oversight, both SGMII-compatible MACs of the LS1021 SoC
> are pointing towards the same internal PCS. Therefore nobody is
> controlling the internal PCS of eTSEC0.
>
> Upon initial ndo_open, the SGMII link is ok by virtue of U-boot
> initialization. But upon an ifdown/ifup sequence, the code path from
> ndo_open -> init_phy -> gfar_configure_serdes does not get executed for
> the PCS of eTSEC0 (and is executed twice for MAC eTSEC1). So the SGMII
> link remains down for eTSEC0. On the LS1021A-TWR board, to signal this
> failure condition, the PHY driver keeps printing
> '803x_aneg_done: SGMII link is not ok'.
>
> Also, it changes compatible of mdio0 to "fsl,etsec2-mdio" to match
> mdio1 device.

It actually changes compatible of both devices.

> +++ b/arch/arm/boot/dts/ls1021a.dtsi
> @@ -584,7 +584,7 @@
> };
>
> mdio0: mdio@2d24000 {
> - compatible = "gianfar";
> + compatible = "fsl,etsec2-mdio";
> device_type = "mdio";
> #address-cells = <1>;
> #size-cells = <0>;
> @@ -592,6 +592,15 @@
> <0x0 0x2d10030 0x0 0x4>;
> };
>
> + mdio1: mdio@2d64000 {
> + compatible = "fsl,etsec2-mdio";


And they trigger different code in the driver:

.type = "mdio",
.compatible = "gianfar",
.data = &(struct fsl_pq_mdio_data) {
...
.get_tbipa = get_gfar_tbipa_from_mdio,
},

.compatible = "fsl,etsec2-mdio",
.data = &(struct fsl_pq_mdio_data) {
...
.get_tbipa = get_etsec_tbipa,
},

Are you sure that is good idea for both mainline and stable?

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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