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    SubjectRe: [PATCH v1 0/3] Meson A1 32-bit support
    On 27/02/2023 15:28, Dmitry Rokosov wrote:
    > Hello Neil!
    >
    > On Mon, Feb 27, 2023 at 09:15:04AM +0100, neil.armstrong@linaro.org wrote:
    >
    > [...]
    >
    >> I'm aware Amlogic also runs their kernel as 32bit to gain a few kbytes
    >> of memory, but those processors are ARMv8 and the arm64 arch code
    >> has been designed for those CPUs.
    >>
    >> So far I didn't find a single good reason to add 32bit support for
    >> ARMv8 Amlogic based SoCs, if you have a solid reason please share.
    >
    > I totally agree with you, but I suppose it's fully related to 'big'
    > Amlogic SoC like S905_ or A311_ series. A113L (aka 'a1') is
    > a cost-efficient dual-core SoC which is used for small, cheap solutions
    > with cheap components. Every cent is important during BoM development.
    > That's why usually ODMs install small ROM and RAM capacity, and each
    > megabyte is important for RAM/ROM kernel and rootfs footprints.

    Do you have figures ? is 32bit ARM kernel really lighter when ARM64 one is correctly configured ?

    > Why am I talking about rootfs? For such small projects a good
    > choice is buildroot rootfs assembling framework. Unfortunatelly,
    > buildroot doesn't support 'compat' mode when kernel and userspace have
    > a different bitness.

    well this is a buildroot problem... the kernel itself is perfectly capable
    of running an AArch32 userspace.

    > In the internal project, we save several
    > percents of ROM/RAM free space using 32-bit configuration (mostly rootfs
    > ROM space, to be honest). Therefore, for such 'little' cost-efficient
    > SoCs we can make an exception and support 32-bit configuration, from my
    > point of view.

    32bit ARM is now "legacy", I would need to have an advice from the ARM SoC
    maintainers, but AFAIK new ARMv8 SoCs should stay in arm64 arch.

    Arnd ? Olof ? do you have an opinion on this ?

    >
    > What do you think about that?

    >>
    >> And as Krzysztof stated, the support is incomplete and cannot work
    >> without a dts file.
    >
    > Agreed, we shouldn't merge dead code. But there are several question to
    > discuss there. Please check my reply to Krzysztof message.
    >
    > [...]
    >

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