From: Peter Griffin <peter.griffin@linaro.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel@stlinux.com, arnd@arndb.de
Subject: Re: [STLinux Kernel] [PATCH] ARM: dts: STi: stih407-family: Disable reserved-memory co-processor nodes
Date: Tue, 7 Jun 2016 09:50:45 +0100 [thread overview]
Message-ID: <20160607085045.GA23181@griffinp-ThinkPad-X1-Carbon-2nd> (raw)
In-Reply-To: <20160607083724.18599-1-lee.jones@linaro.org>
On Tue, 07 Jun 2016, Lee Jones wrote:
> This patch fixes a non-booting issue in Mainline.
>
> When booting with a compressed kernel, we need to be careful how we
> populate memory close to DDR start. AUTO_ZRELADDR is enabled by default
> in multi-arch enabled configurations, which place some restrictions on
> where the kernel is placed and where it will be uncompressed to on boot.
>
> AUTO_ZRELADDR takes the decompressor code's start address and masks out
> the bottom 28 bits to obtain an address to uncompress the kernel to
> (thus a load address of 0x42000000 means that the kernel will be
> uncompressed to 0x40000000 i.e. DDR START on this platform).
>
> Even changing the load address to after the co-processor's shared memory
> won't render a booting platform, since the AUTO_ZRELADDR algorithm still
> ensures the kernel is uncompressed into memory shared with the first
> co-processor (0x40000000).
>
> Another option would be to move loading to 0x4A000000, since this will
> mean the decompressor will decompress the kernel to 0x48000000. However,
> this would mean a large chunk (0x44000000 => 0x48000000 (64MB)) of
> memory would essentially be wasted for no good reason.
>
> Until we can work with ST to find a suitable memory location to
> relocate co-processor shared memory, let's disable the shared memory
> nodes. This will ensure a working platform in the mean time.
>
> NB: The more observant of you will notice that we're leaving the DMU
> shared memory node enabled; this is because a) it is the only one in
> active use at the time of this writing and b) it is not affected by
> the current default behaviour which is causing issues.
>
> Fixes: fe135c6 (ARM: dts: STiH407: Move over to using the 'reserved-memory' API for obtaining DMA memory)
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
> arch/arm/boot/dts/stih407-family.dtsi | 3 +++
> 1 file changed, 3 insertions(+)
Reviewed-by Peter Griffin <peter.griffin@linaro.org>
next prev parent reply other threads:[~2016-06-07 8:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 8:37 [PATCH] ARM: dts: STi: stih407-family: Disable reserved-memory co-processor nodes Lee Jones
2016-06-07 8:50 ` Peter Griffin [this message]
2016-06-17 9:56 ` Maxime Coquelin
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