Re: [PATCH] irqchip/sifive-plic: default to enabled

From: Marc Zyngier
Date: Thu Nov 17 2022 - 14:37:09 EST


On Thu, 17 Nov 2022 18:59:43 +0000,
Conor Dooley <conor@xxxxxxxxxx> wrote:
>
> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>
> The SiFive PLIC driver is used by all current implementations, including
> those that do not have a SiFive PLIC. Default the driver to enabled,
> with the intention of later removing the current "every SOC selects
> this" situation in Kconfig.socs at the moment.
>
> The speculative "potential others" in the description no longer makes
> any sense, as the driver is always used. Update the Kconfig symbol's
> description to reflect the driver's ubiquitous state.
>
> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> ---
> Hey Marc,
>
> I recall some discussion when this driver was extended to other PLICs a
> few months ago:
> https://lore.kernel.org/linux-riscv/20511a05f39408c8ffbcc98923c4abd2@xxxxxxxxxx/
>
> Perhaps I got the wrong impression, but it seemed to me that you intend
> for future implementations to reuse this driver where possible?

Well, within reasons. People seem to have some very liberal
interpretations of the architecture spec...

>
> I'd like to think, and surely will be proven wrong, that ~all future
> plic implementations should be similar enough to fit that bill.
> It's kinda on this basis that I figure switching this thing to default y
> should be okay. It's already only buildable on RISC-V & every
> implementation uses it, so no difference there.

If you expect this to be present at all times, why isn't this selected
by the architecture Kconfig instead? I always find it pretty odd to
have something that is 'default y' and yet constrained by a 'depend
MYARCH'. A 'select PLIC' would make a lot more sense.

And then you can stop making this user selectable.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.