RE: [PATCH 17/18] arm64: dts: renesas: Introduce r8a774b1-beacon-rzg2n-kit

[Biju Das]

Hi Adam,

> Subject: Re: [PATCH 17/18] arm64: dts: renesas: Introduce r8a774b1-beacon-
> rzg2n-kit
> 
> On Thu, Dec 17, 2020 at 5:49 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> wrote:
> >
> > Hi Adam,
> >
> > On Sun, Dec 13, 2020 at 7:38 PM Adam Ford <aford173@xxxxxxxxx> wrote:
> > > Beacon EmebeddedWorks is introducing a new kit based on the RZ/G2N
> > > SoC from Renesas.
> > >
> > > The SOM supports eMMC, WiFi and Bluetooth, along with a Cat-M1
> > > cellular radio.
> > >
> > > The Baseboard has Ethernet, USB, HDMI, stereo audio in and out,
> > > along with a variety of push buttons and LED's, and support for a
> > > parallel RGB and an LVDS display.  It uses the same baseboard and
> > > SOM as the RZ/G2M.
> > >
> > > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> >
> > Thanks for your patch!
> 
> Thank you for the review!
> 
> >
> > > --- /dev/null
> > > +++ b/arch/arm64/boot/dts/renesas/r8a774b1-beacon-rzg2n-kit.dts
> > > @@ -0,0 +1,43 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright 2020, Compass Electronics Group, LLC  */
> > > +
> > > +/dts-v1/;
> > > +
> > > +#include "r8a774b1.dtsi"
> > > +#include "beacon-renesom-som.dtsi"
> > > +#include "beacon-renesom-baseboard.dtsi"
> > > +
> > > +/ {
> > > +       model = "Beacon Embedded Works RZ/G2N Development Kit";
> > > +       compatible =    "beacon,beacon-rzg2n", "renesas,r8a774b1";
> > > +
> > > +       aliases {
> > > +               serial0 = &scif2;
> > > +               serial1 = &hscif0;
> > > +               serial2 = &hscif1;
> > > +               serial3 = &scif0;
> > > +               serial4 = &hscif2;
> > > +               serial5 = &scif5;
> > > +               serial6 = &scif4;
> > > +               ethernet0 = &avb;
> > > +       };
> > > +
> > > +       chosen {
> > > +               stdout-path = "serial0:115200n8";
> > > +       };
> >
> > No memory nodes? Are you relying on U-Boot to fill them in?
> > If yes, why do you have them in the other board DTS files?
> 
> There is already a memory node included in the beacon-renesom.dtsi file
> which is defining memory@48000000 node which is common to the M,
> N and H.   If I understand it correctly, the extra memory nodes
> defined in the higher-level dts for M and H variation are not applicable
> on the N.

If I am correct, It is not applicable, if it has only 2GB memory for the N variant.

But If it has 4GB memory(1ch x4GB), then the memory is split between 32bit space(first 2GB) and 64 bit space(remaining 2GB). 
In this case you need to define extra DT node for memory in 64bit space.

Cheers,
Biju