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Message-ID: <664f3b7d-d629-5af1-cae4-cb5b638a5da1@mediatek.com>
Date:   Tue, 27 Sep 2022 12:00:28 +0800
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Subject: Re: [PATCH] arm64: dts: mediatek: mt8195-demo: fix the memory size of
 node secmon
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To:     Miles Chen <miles.chen@mediatek.com>
CC:     <bear.wang@mediatek.com>, <devicetree@vger.kernel.org>,
        <fparent@baylibre.com>, <krzysztof.kozlowski+dt@linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-mediatek@lists.infradead.org>, <linux-usb@vger.kernel.org>,
        <macpaul@gmail.com>, <matthias.bgg@gmail.com>,
        <pablo.sun@mediatek.com>, <robh+dt@kernel.org>,
        <stable@vger.kernel.org>
References: <20220922091648.2821-1-macpaul.lin@mediatek.com>
 <20220926070544.13257-1-miles.chen@mediatek.com>
From:   Macpaul Lin <macpaul.lin@mediatek.com>
In-Reply-To: <20220926070544.13257-1-miles.chen@mediatek.com>
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On 9/26/22 15:05, Miles Chen wrote:
> Hi Macpaul,
> 
>> The size of device tree node secmon (bl31_secmon_reserved) was
>> incorrect. It should be increased to 2MiB (0x200000).
> 
> 192K should work when the patch(6147314aeedc) was accepted.
> Does the trusted-firmware-a get larger now, so we need to
> increase the size to 2MiB?
> 
> thanks,
> Miles

When mt8195-demo.dts sent to the upstream, at that time the size of
BL31 was small. Because supported functions and modules in BL31 are 
basic sets when the board was under early development stage.

Now BL31 includes more firmwares of coprocessors and maturer functions
so the size has grown bigger in real applications. According to the 
value reported by customers, we think reserved 2MiB for BL31 might be 
enough for maybe the following 2 or 3 years.

>>
>> The origin setting will cause some abnormal behavior due to
>> trusted-firmware-a and related firmware didn't load correctly.
>> The incorrect behavior may vary because of different software stacks.
>> For example, it will cause build error in some Yocto project because
>> it will check if there was enough memory to load trusted-firmware-a
>> to the reserved memory.
>>
>> Cc: stable@vger.kernel.org      # v5.19
>> Fixes: 6147314aeedc ("arm64: dts: mediatek: Add device-tree for MT8195 Demo board")
>> Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>

Thanks
Macpaul Lin