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Subject: Re: [PATCH] ARM: bcm2835_defconfig: add minimal support for
 Raspberry Pi4
To:     Stefan Wahren <stefan.wahren@i2se.com>,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        linux-rpi-kernel@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <8bd7a25a-359d-5b30-4c95-004032d78cb6@samsung.com>
Date:   Fri, 14 Feb 2020 13:25:59 +0100
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Hi Stefan,

On 13.02.2020 10:59, Stefan Wahren wrote:
> On 13.02.20 08:35, Marek Szyprowski wrote:
>> On 12.02.2020 19:31, Nicolas Saenz Julienne wrote:
>>> On Wed, 2020-02-12 at 11:20 +0100, Marek Szyprowski wrote:
>>>> Add drivers for the minimal set of devices needed to boot Raspberry Pi4
>>>> board.
>>>>
>>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> Just so you know, the amount of support on the RPi4 you might be able to get
>>> updating bcm2835_defconfig's config is very limited. Only 1GB of ram and no
>>> PCIe (so no USBs).
>> Yes, I know. A lots of core features is missing: SMP, HIGHMEM, LPAE, PCI
>> and so on, but having a possibility to boot RPi4 with this defconfig
>> increases the test coverage.
> in case you want to increase test coverage, we better enable all
> Raspberry Pi 4 relevant hardware parts (hwrng, thermal, PCI ...). This
> is what we did for older Pi boards.

Okay, I will add thermal in v2. HWRNG is already selected as module. 
Enabling PCI without LPAE makes no sense as the driver won't be able to 
initialize properly.

> SMP, HIGHMEM, LPAE are different and shouldn't be enabled in
> bcm2835_defconfig from my PoV.

Maybe it would make sense to also add bcm2711_defconfig or 
bcm2835_lpae_defconfig?

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland