Re: [PATCH 2/2] docs: dt: allow case-insensitive RISC-V ISA string

Re: [PATCH 2/2] docs: dt: allow case-insensitive RISC-V ISA string

[Conor Dooley]

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Hey Yangyu Chen,

On Tue, Apr 25, 2023 at 08:00:16PM +0800, Yangyu Chen wrote:
> After allowing case-insensitive ISA string parsing in the kernel code,
> the docs should be updated.

As I pointed out in my reply to your cover letter [1], I don't think this
patch is backwards compatible, and should instead be fixed in
rocket-chip's codebase, where it appears the capital letters were added
without actually testing the output against the binding.
If we allow caps here, booting old kernels with new devicetrees may
experience the crash you mention in your cover letter.

NAK, on the basis that this should be fixed in rocket-chip (or any other
core-generator that outputs invalid devicetrees).

Otherwise, the $subject doesn't match what is used for dt-bindings (use
`git log --oneline -- /path/to/file` for examples) nor did you CC the
output of get_maintainer.pl, with the devicetree maintainers notably
being absent.

Cheers,
Conor.

1 - https://lore.kernel.org/linux-riscv/20230425-flyable-prompter-5b1e4cebf9db@wendy/

> Signed-off-by: Yangyu Chen <cyy@cyyself.name>
> ---
>  Documentation/devicetree/bindings/riscv/cpus.yaml | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml
> index 001931d526ec..70afd1e8638b 100644
> --- a/Documentation/devicetree/bindings/riscv/cpus.yaml
> +++ b/Documentation/devicetree/bindings/riscv/cpus.yaml
> @@ -79,11 +79,10 @@ properties:
>        User-Level ISA document, available from
>        https://riscv.org/specifications/
>  
> -      While the isa strings in ISA specification are case
> -      insensitive, letters in the riscv,isa string must be all
> -      lowercase to simplify parsing.
> +      According to RISC-V ISA specification, the isa strings are
> +      case insensitive.
>      $ref: "/schemas/types.yaml#/definitions/string"
> -    pattern: ^rv(?:64|32)imaf?d?q?c?b?k?j?p?v?h?(?:[hsxz](?:[a-z])+)?(?:_[hsxz](?:[a-z])+)*$
> +    pattern: (?i)^rv(?:64|32)imaf?d?q?c?b?k?j?p?v?h?(?:[hsxz](?:[a-z])+)?(?:_[hsxz](?:[a-z])+)*$
>  
>    # RISC-V requires 'timebase-frequency' in /cpus, so disallow it here
>    timebase-frequency: false
> -- 
> 2.40.0
> 

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