Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:6 as permitted sender) client-ip=2620:137:e000::3:6;
MIME-Version: 1.0
Date:   Wed, 04 Oct 2023 19:16:52 +0200
From:   Michael Walle <mwalle@kernel.org>
To:     Simon Glass <sjg@chromium.org>
Cc:     miquel.raynal@bootlin.com, conor+dt@kernel.org,
        devicetree@vger.kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
        ptyadav@amazon.de, rafal@milecki.pl, richard@nod.at,
        robh+dt@kernel.org, robh@kernel.org, trini@konsulko.com,
        u-boot@lists.denx.de, vigneshr@ti.com
Subject: Re: [PATCH v2 1/3] dt-bindings: mtd: fixed-partitions: Add binman
 compatible
In-Reply-To: <CAPnjgZ2hWE6Sc=rg55W=-r-TnoWP7Y5gSpn41kwoyja-AMVw+w@mail.gmail.com>
References: <20231004093620.2b1d6917@xps-13>
 <20231004113458.531124-1-mwalle@kernel.org>
 <CAPnjgZ2hWE6Sc=rg55W=-r-TnoWP7Y5gSpn41kwoyja-AMVw+w@mail.gmail.com>
Message-ID: <9e588e3ec8c0c321a2861723d0d42b9a@kernel.org>
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hi,

>> >> Add a compatible string for binman, so we can extend fixed-partitions
>> >> in various ways.
>> >
>> > I've been thinking at the proper way to describe the binman partitions.
>> > I am wondering if we should really extend the fixed-partitions
>> > schema. This description is really basic and kind of supposed to remain
>> > like that. Instead, I wonder if we should not just keep the binman
>> > compatible alone, like many others already. This way it would be very clear
>> > what is expected and allowed in both cases. I am thinking about
>> > something like that:
>> >
>> >       Documentation/devicetree/bindings/mtd/partitions/brcm,bcm4908-partitions.yaml
>> >
>> > this file is also referenced there (but this patch does the same, which
>> > is what I'd expect):
>> >
>> >       Documentation/devicetree/bindings/mtd/partitions/partitions.yaml
>> >
>> > I'll let the binding maintainers judge whether they think it's
>> > relevant, it's not a strong opposition.
>> 
>> What is the overall goal here? To replace the current binman node 
>> which is
>> usually contained in the -u-boot.dtsi files? If one is using binman to
>> create an image, is it expected that one needs to adapt the DT in 
>> linux?
>> Or will it still be a seperate -u-boot.dtsi? > Because in the latter 
>> case
>> I see that there will be conflicts because you have to overwrite the
>> flash node. Or will it be a seperate node with all the information
>> duplicated?
> 
> The goal is simply to have a full binding for firmware layout, such
> that firmware images can be created, examined and updated. The
> -u-boot.dtsi files are a stopgap while we sort out a real binding.
> They should eventually go away.

You haven't answered whether this node should be a seperate binman
node - or if you'll reuse the existing flash (partitions) node(s) and
add any missing property there. If it's the latter, I don't think
compatible = "binman", "fixed-partitions"; is correct.

>> Maybe (a more complete) example would be helpful.
> 
> Can you please be a bit more specific? What is missing from the 
> example?

Like a complete (stripped) DTS. Right now I just see how the individual
node looks like. But with a complete example DTS, my question from above
would have been answered.

What if a board uses eMMC to store the firmware binaries? Will that then
be a subnode to the eMMC device?

-michael