[PATCH linux dev-5.15] ARM: dts: aspeed: ast2600-evb: Enable RX delay on MAC0/MAC1

[Troy Lee]

Hi Joel,
> -----Original Message-----
> From: Joel Stanley <joel at jms.id.au>
> Sent: Friday, March 18, 2022 10:22 AM
> To: Howard Chiu <howard_chiu at aspeedtech.com>; Jeremy Kerr
> <jk at ozlabs.org>
> Cc: openbmc at lists.ozlabs.org; Troy Lee <troy_lee at aspeedtech.com>
> Subject: Re: [PATCH linux dev-5.15] ARM: dts: aspeed: ast2600-evb: Enable
> RX delay on MAC0/MAC1
> 
> On Thu, 17 Mar 2022 at 06:30, Howard Chiu
> <howard_chiu at aspeedtech.com> wrote:
> >
> > The property 'phy-mode' on ast2600 mac0 and mac1 is recommended to
> set to 'rgmii-rxid'
> > which enables the RX interface delay from the PHY chip.
> > Refer page 45 of SDK User Guide v08.00
> >
> > Signed-off-by: Howard Chiu <howard_chiu at aspeedtech.com>
> 
> Thanks Howard. This makes MAC0 on my AST2600A3 evb work again!
> 
> mac1 was working fine without the patch. Do you know why?
> Why do we do this for mac0 and mac1, but not mac2 and mac3? 
Mac0/1 and mac2/3 are physically located on different die, so they have different properties by nature. 
Mac0/1 has smaller delay step. 

> Because the user guide is not public, can you please quote the relevant
> information in the commit message.
The SDK User Guide can be download from Aspeed github.
https://github.com/AspeedTech-BMC/openbmc/releases/download/v08.00/SDK_User_Guide_v08.00.pdf

Thanks for testing, do you think this patch should send upstream mainline as well?

Troy Lee

> Tested-by: Joel Stanley <joel at jms.id.au>
> 
> > ---
> >  arch/arm/boot/dts/aspeed-ast2600-evb.dts | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > b/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > index a6382082d38c..9a1979541d2d 100644
> > --- a/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > +++ b/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > @@ -116,7 +116,7 @@ ethphy3: ethernet-phy at 0 {
> >  &mac0 {
> >         status = "okay";
> >
> > -       phy-mode = "rgmii";
> > +       phy-mode = "rgmii-rxid";
> >         phy-handle = <&ethphy0>;
> >
> >         pinctrl-names = "default";
> > @@ -127,7 +127,7 @@ &mac0 {
> >  &mac1 {
> >         status = "okay";
> >
> > -       phy-mode = "rgmii";
> > +       phy-mode = "rgmii-rxid";
> >         phy-handle = <&ethphy1>;
> >
> >         pinctrl-names = "default";
> > --
> > 2.25.1
> >