Re: [PATCH 2/7] gpu: nova-core: Add support to convert bitfield to underlying type

[John Hubbard <jhubbard@nvidia.com>]

On 10/20/25 11:55 AM, Joel Fernandes wrote:
> To support the usecase where we read a register and write to another
> with identical bit layout, add support to convert bitfield to underlying type.
> 
> Another way to do this, is to read individual fields, on the caller
> side, and write to the destination fields, but that is both cumbersome
> and error-prone as new bits added in hardware may be missed.
> 
> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
> ---
>  drivers/gpu/nova-core/bitfield.rs | 7 +++++++
>  1 file changed, 7 insertions(+)

Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard

> 
> diff --git a/drivers/gpu/nova-core/bitfield.rs b/drivers/gpu/nova-core/bitfield.rs
> index 0994505393dd..2266abc3f7ab 100644
> --- a/drivers/gpu/nova-core/bitfield.rs
> +++ b/drivers/gpu/nova-core/bitfield.rs
> @@ -72,6 +72,7 @@
>  /// - Field setters: `set_mode()`, `set_state()`, etc. (supports chaining with builder pattern).
>  ///   Note that the compiler will error out if the size of the setter's arg exceeds the
>  ///   struct's storage size.
> +/// - Conversion from the underlying storage type (e.g., `From<u32>`).
>  /// - Debug and Default implementations.
>  ///
>  /// Note: Field accessors and setters inherit the same visibility as the struct itself.
> @@ -117,6 +118,12 @@ fn from(val: $name) -> $storage {
>              }
>          }
>  
> +        impl ::core::convert::From<$storage> for $name {
> +            fn from(val: $storage) -> $name {
> +                $name(val)
> +            }
> +        }
> +
>          bitfield!(@fields_dispatcher $vis $name $storage { $($fields)* });
>      };
>