Re: [PATCH 4/4] arm64: dts: renesas: Add HiHope RZ/G2N main board support

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Biju,

On Fri, Sep 27, 2019 at 2:56 PM Biju Das <biju.das@bp.renesas.com> wrote:
> > Subject: Re: [PATCH 4/4] arm64: dts: renesas: Add HiHope RZ/G2N main
> > board support
> > On Tue, Sep 17, 2019 at 3:12 PM Biju Das <biju.das@bp.renesas.com> wrote:
> > > Basic support for the HiHope RZ/G2N main board:
> > >   - Memory,
> > >   - Main crystal,
> > >   - Serial console
> > >
> > > Signed-off-by: Biju Das <biju.das@bp.renesas.com>
> >
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >
> > One question below...
> >
> > > --- /dev/null
> > > +++ b/arch/arm64/boot/dts/renesas/r8a774b1-hihope-rzg2n.dts
> > > @@ -0,0 +1,26 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Device Tree Source for the HiHope RZ/G2N main board
> > > + *
> > > + * Copyright (C) 2019 Renesas Electronics Corp.
> > > + */
> > > +
> > > +/dts-v1/;
> > > +#include "r8a774b1.dtsi"
> > > +#include "hihope-common.dtsi"
> > > +
> > > +/ {
> > > +       model = "HopeRun HiHope RZ/G2N main board based on r8a774b1";
> > > +       compatible = "hoperun,hihope-rzg2n", "renesas,r8a774b1";
> > > +
> > > +       memory@48000000 {
> > > +               device_type = "memory";
> > > +               /* first 128MB is reserved for secure area. */
> > > +               reg = <0x0 0x48000000 0x0 0x78000000>;
> > > +       };
> > > +
> > > +       memory@480000000 {
> > > +               device_type = "memory";
> > > +               reg = <0x4 0x80000000 0x0 0x80000000>;
> > > +       };
> > > +};
> >
> > So both the HiHope RZ/G2M and RZ/G2N boards have 4 GiB of RAM, while
> > the latter has a narrower memory bus, so it must be wired differently?
>
> RZ/G2M is LPDDR4-3200 with 32 bits × 2 channels,  where as RZ/G2N is LPDDR4-3200 with 32 bits × 1 channel.
> RZ/G2M can have split mapping where as RZ/G2N can have only linear mapping.

Thanks for the confirmation, will queue in renesas-devel for v5.5.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds