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From:   "Matwey V. Kornilov" <matwey@sai.msu.ru>
Date:   Mon, 6 Jan 2020 23:47:36 +0300
Message-ID: <CAJs94EbUL6o9sM+pwxwpqHVDkFqy7wFRirET-Vq3SNVd3grUsA@mail.gmail.com>
Subject: Re: [PATCH] arm: dts: am335x-boneblack-common: fix memory size
To:     Robert Nelson <robertcnelson@gmail.com>
Cc:     =?UTF-8?Q?Beno=C3=AEt_Cousson?= <bcousson@baylibre.com>,
        Tony Lindgren <tony@atomide.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        "open list:OMAP DEVICE TREE SUPPORT" <linux-omap@vger.kernel.org>,
        "open list:OMAP DEVICE TREE SUPPORT" <devicetree@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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пн, 6 янв. 2020 г. в 23:44, Robert Nelson <robertcnelson@gmail.com>:
>
> On Mon, Jan 6, 2020 at 7:10 AM Matwey V. Kornilov <matwey@sai.msu.ru> wrote:
> >
> > BeagleBone Black series is equipped with 512MB RAM
> > whereas only 256MB is included from am335x-bone-common.dtsi
>
> FYI: While all versions from the factory are 512MB, some 3rd parties
> offered 1GB reballing upgrades..
>
> and the SanCloud variant which uses this file, was built with 1GB:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am335x-sancloud-bbe.dts
>
> >
> > This leads to an issue with unusual setups when devicetree
> > is loaded by GRUB2 directly.
>
> It's a miracle, since when did GRUB2 gain this ability?
>

I am not sure about when. But Grub 2.02 has devicetree command, which
can be used as the following:

        echo "Loading device tree blob ..."
        devicetree (tftp)/dtb/am335x-boneblack.dtb

And you know, you can run Grub itself as EFI application on to of u-boot.

> >
> > Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
> > ---
> >  arch/arm/boot/dts/am335x-boneblack-common.dtsi | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/am335x-boneblack-common.dtsi b/arch/arm/boot/dts/am335x-boneblack-common.dtsi
> > index 7ad079861efd..91f93bc89716 100644
> > --- a/arch/arm/boot/dts/am335x-boneblack-common.dtsi
> > +++ b/arch/arm/boot/dts/am335x-boneblack-common.dtsi
> > @@ -131,6 +131,11 @@
> >  };
> >
> >  / {
> > +       memory@80000000 {
> > +               device_type = "memory";
> > +               reg = <0x80000000 0x20000000>; /* 512 MB */
> > +       };
> > +
> >         clk_mcasp0_fixed: clk_mcasp0_fixed {
> >                 #clock-cells = <0>;
> >                 compatible = "fixed-clock";
> > --
> > 2.16.4
> >
>
>
> --
> Robert Nelson
> https://rcn-ee.com/


-- 
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119234, Moscow, Universitetsky pr-k 13, +7 (495) 9392382