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From:   Rob Herring <robh+dt@kernel.org>
Date:   Tue, 5 Jan 2021 08:37:21 -0700
Message-ID: <CAL_Jsq+0dL=LHo8r9mY_weBP_bQ97UOBnt596J3JoVHwGNinHA@mail.gmail.com>
Subject: Re: [RFC 2/2] scripts: dtc: Handle outform dtbo
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Frank Rowand <frowand.list@gmail.com>,
        devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Bill Mills <bill.mills@linaro.org>, tero.kristo@gmail.com
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On Tue, Jan 5, 2021 at 4:24 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> Update dtc compiler to accept dtbo as an outform.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> ---
> I feel that this needs to go directly to
> https://git.kernel.org/pub/scm/utils/dtc/dtc.git
>
> Right ? I will send it separately if the idea is accepted here.

Yes, needs to go to devicetree-compiler list. I think this came up
before and IIRC David wasn't completely in agreement. I looked briefly
and couldn't find the thread though...

We really don't need a different extension because we could just
examine the dtb to determine if it is an overlay or not. That's less
obvious. We could also add meta-data to overlays defining what base
they apply to. If we had that, a tool could just list all overlays
that should apply to a base and we could use that info for build time
applying overlays. Of course, that and a dtbo extension/format are not
mutually exclusive.

> ---
>  scripts/dtc/dtc.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/scripts/dtc/dtc.c b/scripts/dtc/dtc.c
> index bdb3f5945699..40fa7128b3d6 100644
> --- a/scripts/dtc/dtc.c
> +++ b/scripts/dtc/dtc.c
> @@ -357,6 +357,8 @@ int main(int argc, char *argv[])
>  #endif
>         } else if (streq(outform, "dtb")) {
>                 dt_to_blob(outf, dti, outversion);
> +       } else if (streq(outform, "dtbo")) {
> +               dt_to_blob(outf, dti, outversion);
>         } else if (streq(outform, "asm")) {
>                 dt_to_asm(outf, dti, outversion);
>         } else if (streq(outform, "null")) {

You also need to extend guess_type_by_name().


Rob