Re: [PATCH AUTOSEL 4.19 03/11] irqchip/sifive-plic: Add missing thead,c900-plic match string

Pavel Machek
2022-02-20T09:55:04Z

[-- Attachment #1: Type: text/plain, Size: 1135 bytes --]

Hi!

> [ Upstream commit 1d4df649cbb4b26d19bea38ecff4b65b10a1bbca ]
>
> The thead,c900-plic has been used in opensbi to distinguish
> PLIC [1]. Although PLICs have the same behaviors in Linux,
> they are different hardware with some custom initializing in
> firmware(opensbi).
>
> Qute opensbi patch commit-msg by Samuel:
>
> The T-HEAD PLIC implementation requires setting a delegation bit
> to allow access from S-mode. Now that the T-HEAD PLIC has its own
> compatible string, set this bit automatically from the PLIC driver,
> instead of reaching into the PLIC's MMIO space from another driver.
>
> [1]: https://github.com/riscv-software-src/opensbi/commit/78c2b19218bd62653b9fb31623a42ced45f38ea6
>

The "thead,c900-plic" string is added into single place in the
kernel. This means that a) it will probably not do anything useful in
-stable kernels and b) it is certainly missing documentation etc.

In mainline, string is documented in
Documentation/devicetree/bindings/interrupt-controller/sifive,plic-1.0.0.yaml

Best regards,
Pavel
--
http://www.livejournal.com/~pavelmachek

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]