RE: [EXT] Re: [PATCH 02/11] dts: mvebu: Update A8K AP806 SDHCI settings

[Kostya Porotchkin]

> -----Original Message-----
> From: linux-arm-kernel <linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx> On
> Behalf Of Kostya Porotchkin
> Sent: Wednesday, February 3, 2021 16:51
> To: Russell King - ARM Linux admin <linux@xxxxxxxxxxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx; Baruch Siach <baruch@xxxxxxxxxx>;
> andrew@xxxxxxx; jaz@xxxxxxxxxxxx; gregory.clement@xxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Nadav Haklai <nadavh@xxxxxxxxxxx>;
> robh+dt@xxxxxxxxxx; Stefan Chulski <stefanc@xxxxxxxxxxx>;
> mw@xxxxxxxxxxxx; Ben Peled <bpeled@xxxxxxxxxxx>; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; sebastian.hesselbarth@xxxxxxxxx
> Subject: RE: [EXT] Re: [PATCH 02/11] dts: mvebu: Update A8K AP806 SDHCI
> settings

[KP] 
> > > > Hi Konstantin,
> > > >
> > > > On Wed, Feb 03 2021, kostap@xxxxxxxxxxx wrote:
> > > > > From: Konstantin Porotchkin <kostap@xxxxxxxxxxx>
> > > > >
> > > > > Update the settings for AP806 SDHCI interface according to
> > > > > latest Xenon drivers changes.
> > > > > - no need to select the PHY slow mode anymore
> > > >
> > > > Why? Has anything changed since the introduction of
> > > > marvell,xenon-phy-slow- mode?
> > > [KP] AP806 B0, AP807 and later do not need the "slow mode" set by
> > > the
> > default.
> > > The HWE-7296210 errata is not applicable to these components and
> > > they are able to run  AP SDHCI in HS400 8-bit mode.
> >
> > So what about all those people, such as me, who have A0 silicon on
> > their Macchiatobin boards?
> >
> > You can't just go around removing DT properties like this.
> >
> [KP] So for older systems this "slow mode" parameter could be set on the
> board level.
> When it is set in ap80x,dtsi file it downgrades all systems to HS-SDR52, even if
> they support HS400 on AP side.
> MacchiatoBIN AP eMMC is connected to 3.3v regulator and has "no-1-8-v" flag
> set, so it should remain in low speed anyway.
[KP] I also forgot to mention this code piece in Xenon driver:
	/* Disable HS200 on Armada AP806 */
	if (priv->hw_version == XENON_AP806)
		host->quirks2 |= SDHCI_QUIRK2_BROKEN_HS200;

> 
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