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From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] of/fdt: export fdt blob as /sys/firmware/fdt
Date: Mon, 10 Nov 2014 17:57:32 +0100	[thread overview]
Message-ID: <3340387.dB5eK3mRnu@wuerfel> (raw)
In-Reply-To: <1415638305-24463-1-git-send-email-ard.biesheuvel@linaro.org>

On Monday 10 November 2014 17:51:45 Ard Biesheuvel wrote:
> Create a new /sys entry '/sys/firmware/fdt' to export the FDT blob
> that was passed to the kernel by the bootloader. This allows userland
> applications such as kexec to access the raw binary.
> 
> The fact that this node does not reside under /sys/firmware/device-tree
> is deliberate: FDT is also used on arm64 UEFI/ACPI systems to
> communicate just the UEFI and ACPI entry points, but the FDT is never
> unflattened and used to configure the system.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Can you elaborate on the motivation? Initially the fdt format was
introduced to make it easy to pass the information from /proc/device-tree
to the next kernel for kexec. Are you interested in cases where this does
not work?

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Cc: Ard Biesheuvel
	<ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
	leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
	geoff.levand-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
	mark.rutland-5wv7dgnIgG8@public.gmane.org,
	rob.herring-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] of/fdt: export fdt blob as /sys/firmware/fdt
Date: Mon, 10 Nov 2014 17:57:32 +0100	[thread overview]
Message-ID: <3340387.dB5eK3mRnu@wuerfel> (raw)
In-Reply-To: <1415638305-24463-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

On Monday 10 November 2014 17:51:45 Ard Biesheuvel wrote:
> Create a new /sys entry '/sys/firmware/fdt' to export the FDT blob
> that was passed to the kernel by the bootloader. This allows userland
> applications such as kexec to access the raw binary.
> 
> The fact that this node does not reside under /sys/firmware/device-tree
> is deliberate: FDT is also used on arm64 UEFI/ACPI systems to
> communicate just the UEFI and ACPI entry points, but the FDT is never
> unflattened and used to configure the system.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Can you elaborate on the motivation? Initially the fdt format was
introduced to make it easy to pass the information from /proc/device-tree
to the next kernel for kexec. Are you interested in cases where this does
not work?

	Arnd
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  reply	other threads:[~2014-11-10 16:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-10 16:51 [PATCH] of/fdt: export fdt blob as /sys/firmware/fdt Ard Biesheuvel
2014-11-10 16:51 ` Ard Biesheuvel
2014-11-10 16:57 ` Arnd Bergmann [this message]
2014-11-10 16:57   ` Arnd Bergmann
2014-11-10 17:08   ` Ard Biesheuvel
2014-11-10 17:08     ` Ard Biesheuvel
2014-11-10 18:02     ` Arnd Bergmann
2014-11-10 18:02       ` Arnd Bergmann

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