From: Dmitry Rokosov <ddrokosov@sberdevices.ru>
To: <neil.armstrong@linaro.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>, <robh+dt@kernel.org>,
<krzysztof.kozlowski+dt@linaro.org>, <khilman@baylibre.com>,
<jbrunet@baylibre.com>, <martin.blumenstingl@googlemail.com>,
<linus.walleij@linaro.org>, <devicetree@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-amlogic@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <kernel@sberdevices.ru>
Subject: Re: [PATCH v1 0/3] Meson A1 32-bit support
Date: Mon, 27 Feb 2023 17:28:09 +0300 [thread overview]
Message-ID: <20230227142809.kujmrraf3pcdhqyn@CAB-WSD-L081021> (raw)
In-Reply-To: <8e5f9bfa-d612-cd43-d722-d04c40938c62@linaro.org>
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.
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. 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.
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.
[...]
--
Thank you,
Dmitry
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next prev parent reply other threads:[~2023-02-27 14:28 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-22 11:50 [PATCH v1 0/3] Meson A1 32-bit support Alexey Romanov
2023-02-22 11:50 ` [PATCH v1 1/3] meson: pinctrl: use CONFIG_PINCTRL_A1 with CONFIG_ARM Alexey Romanov
2023-03-06 13:45 ` Linus Walleij
2023-03-06 13:49 ` neil.armstrong
2023-03-06 13:52 ` Linus Walleij
2023-02-22 11:50 ` [PATCH v1 2/3] firmware: meson: use CONFIG_MESON_SM " Alexey Romanov
2023-02-22 11:50 ` [PATCH v1 3/3] arch/arm: dts: introduce meson-a1 device tree Alexey Romanov
2023-02-23 9:08 ` Krzysztof Kozlowski
2023-02-23 9:09 ` Krzysztof Kozlowski
2023-02-27 14:39 ` Dmitry Rokosov
2023-02-27 14:41 ` Krzysztof Kozlowski
2023-02-27 8:15 ` [PATCH v1 0/3] Meson A1 32-bit support neil.armstrong
2023-02-27 14:28 ` Dmitry Rokosov [this message]
2023-02-27 14:46 ` neil.armstrong
2023-02-27 16:01 ` Dmitry Rokosov
2023-02-27 14:58 ` Arnd Bergmann
2023-02-27 15:51 ` Dmitry Rokosov
2023-02-27 16:15 ` Arnd Bergmann
2023-02-27 16:37 ` Dmitry Rokosov
2023-02-27 16:38 ` Neil Armstrong
2023-02-27 16:50 ` Dmitry Rokosov
2023-02-27 18:19 ` Arnd Bergmann
2023-02-28 8:49 ` Dmitry Rokosov
2023-03-09 21:52 ` Kevin Hilman
2023-03-10 15:20 ` Dmitry Rokosov
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