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Message-ID: <62e767da-5e4f-4b92-a5c9-5d523896d68e@pengutronix.de>
Date:   Wed, 29 Nov 2023 20:16:20 +0100
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Subject: Re: [PATCH v7 2/2] arm64: boot: Support Flat Image Tree
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To:     Tom Rini <trini@konsulko.com>
Cc:     Simon Glass <sjg@chromium.org>,
        linux-arm-kernel@lists.infradead.org,
        Masahiro Yamada <masahiroy@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        U-Boot Mailing List <u-boot@lists.denx.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Terrell <terrelln@fb.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        Will Deacon <will@kernel.org>, linux-kbuild@vger.kernel.org,
        Pengutronix Kernel Team <kernel@pengutronix.de>
References: <20231129172200.430674-1-sjg@chromium.org>
 <20231129172200.430674-3-sjg@chromium.org>
 <30f32467-51ea-47de-a272-38e074f4060b@pengutronix.de>
 <20231129190220.GN2513409@bill-the-cat>
From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
In-Reply-To: <20231129190220.GN2513409@bill-the-cat>
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Hello Tom,

On 29.11.23 20:02, Tom Rini wrote:
> On Wed, Nov 29, 2023 at 07:59:00PM +0100, Ahmad Fatoum wrote:
>> Hi,
>>
>> a few more comments after decompiling the FIT image:
>>
>> On 29.11.23 18:21, Simon Glass wrote:
>>> +    with fsw.add_node('kernel'):
>>> +        fsw.property_string('description', args.name)
>>> +        fsw.property_string('type', 'kernel_noload')
>>
>> The specification only says no loading done, but doesn't explain what it
>> means for a bootloader to _not_ load an image. Looking into the U-Boot commit
>> b9b50e89d317 ("image: Implement IH_TYPE_KERNEL_NOLOAD") that introduces this,
>> apparently no loading means ignoring load and entry address?
>>
>> I presume missing load and entry is something older U-Boot versions
>> were unhappy about? Please let me know if the semantics are as I understood,
>> so I can prepare a barebox patch supporting it.
> 
> So the matching side for this series in U-Boot is:
> https://patchwork.ozlabs.org/project/uboot/list/?series=382849&state=*
> 
> And in short, for IH_TYPE_KERNEL_NOLOAD we do our best to use it
> in-place. For decompression we allocate some space to decompress to.

Thanks. I am still curious why "kernel" couldn't have been used back then
with missing entry and load address to arrive at the same result?

Thanks,
Ahmad


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