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linux/drivers/gpu/nova-core/num.rs

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gpu: nova-core: add functions and traits for lossless integer conversions The core library's `From` implementations do not cover conversions that are not portable or future-proof. For instance, even though it is safe today, `From<usize>` is not implemented for `u64` because of the possibility to support larger-than-64bit architectures in the future. However, the kernel supports a narrower set of architectures, and in the case of Nova we only support 64-bit. This makes it helpful and desirable to provide more infallible conversions, lest we need to rely on the `as` keyword and carry the risk of silently losing data. Thus, introduce a new module `num` that provides safe const functions performing more conversions allowed by the build target, as well as `FromSafeCast` and `IntoSafeCast` traits that are just extensions of `From` and `Into` to conversions that are known to be lossless. Suggested-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/rust-for-linux/DDK4KADWJHMG.1FUPL3SDR26XF@kernel.org/ Acked-by: Danilo Krummrich <dakr@kernel.org> [acourbot@nvidia.com: fix merge conflicts after rebase.] Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Message-ID: <20251029-nova-as-v3-4-6a30c7333ad9@nvidia.com>
2025-10-16 11:55:48 +09:00
rust: make `build_assert` module the home of related macros Given the macro scoping rules, all macros are rendered twice, in the module and in the top-level of kernel crate. Add `#[doc(hidden)]` to the macro definition and `#[doc(inline)]` to the re-export inside `build_assert` module so the top-level items are hidden. [ Sadly, because the definition is hidden, `rustdoc` decides to not list them as re-exports in the `prelude` page anymore, even if we refer to the not-actually-hidden item. - Miguel ] Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Alexandre Courbot <acourbot@nvidia.com> Acked-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Acked-by: Boqun Feng <boqun@kernel.org> Signed-off-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260609142637.373347-1-gary@kernel.org [ Kept a single declaration in the prelude, and reworded since they already had `no_inline`. Removed other imports from `predefine` since we now use the prelude. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-06-09 15:26:33 +01:00
gpu: nova-core: add functions and traits for lossless integer conversions The core library's `From` implementations do not cover conversions that are not portable or future-proof. For instance, even though it is safe today, `From<usize>` is not implemented for `u64` because of the possibility to support larger-than-64bit architectures in the future. However, the kernel supports a narrower set of architectures, and in the case of Nova we only support 64-bit. This makes it helpful and desirable to provide more infallible conversions, lest we need to rely on the `as` keyword and carry the risk of silently losing data. Thus, introduce a new module `num` that provides safe const functions performing more conversions allowed by the build target, as well as `FromSafeCast` and `IntoSafeCast` traits that are just extensions of `From` and `Into` to conversions that are known to be lossless. Suggested-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/rust-for-linux/DDK4KADWJHMG.1FUPL3SDR26XF@kernel.org/ Acked-by: Danilo Krummrich <dakr@kernel.org> [acourbot@nvidia.com: fix merge conflicts after rebase.] Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Message-ID: <20251029-nova-as-v3-4-6a30c7333ad9@nvidia.com>
2025-10-16 11:55:48 +09:00
gpu: nova-core: num: add functions to safely convert a const value to a smaller type There are times where we need to store a constant value defined as a larger type (e.g. through a binding) into a smaller type, knowing that the value will fit. Rust, unfortunately, only provides us with the `as` operator for that purpose, the use of which is discouraged as it silently strips data. Extend the `num` module with functions allowing to perform the conversion infallibly, at compile time. Example: const FOO_VALUE: u32 = 1; // `FOO_VALUE` fits into a `u8`, so the conversion is valid. let foo = num::u32_to_u8::<{ FOO_VALUE }>(); We are going to use this feature extensively in Nova. Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com> [acourbot@nvidia.com: fix mistake in example pointed out by Mikko.] Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Message-ID: <20251110-gsp_boot-v9-3-8ae4058e3c0e@nvidia.com>
2025-11-10 22:34:11 +09:00
gpu: nova-core: introduce `bounded_enum` macro Introduce a powered-up version of our ad-hoc `impl_from_enum_to_u8` macro that allows the definition of an enum type associated to a `Bounded` of a given width, and provides the `From` and `TryFrom` implementations required to use that enum as a register field member. This allows us to generate the required conversion implementations for using the kernel register macro and skip some tedious boilerplate. Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://patch.msgid.link/20260325-b4-nova-register-v4-1-bdf172f0f6ca@nvidia.com Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
2026-03-25 11:46:14 +09:00