For struct-like GMCAPI messages encoding field by field manually is noisy. Add some type machinery and a macro to automate encoding of struct-like messages. The `Encodeable` trait can be implemented by any type to say that it can be encoded into an NVKV `Encoder`. Add a simple `nvkv_encode!` macro that works on structs and encodes each field in order. Provide some base types, such as `Key` which statically associates a NVKV key with some value, to avoid having to make a lot of newtypes and implement `Encodeable` on them.
Signed-off-by: Eliot Courtney <[email protected]> --- drivers/gpu/nova-core/gsp/nvkv.rs | 49 +++++++++ drivers/gpu/nova-core/gsp/nvkv/encode.rs | 178 +++++++++++++++++++++++++++++++ 2 files changed, 227 insertions(+) diff --git a/drivers/gpu/nova-core/gsp/nvkv.rs b/drivers/gpu/nova-core/gsp/nvkv.rs index 64d8d0118452..bf6500d54b21 100644 --- a/drivers/gpu/nova-core/gsp/nvkv.rs +++ b/drivers/gpu/nova-core/gsp/nvkv.rs @@ -10,6 +10,13 @@ //! naturally maps to storing a &str with the GPU name. #![expect(unused_imports)] +#![cfg_attr(not(CONFIG_KUNIT), expect(unused_macros))] + +use core::marker::PhantomData; +use core::ops::{ + Deref, + DerefMut, // +}; use kernel::{ bitfield, @@ -29,6 +36,48 @@ /// The index of an NVKV value. pub(crate) type Index = Bounded<u64, 12>; +/// A static association between an NVKV key `KEY_ID` and the storage of its value. +/// +/// Use with the encoder or decoder macros `nvkv_encode!` and `nvkv_decode!` to let them know how to +/// map the value `Key<T, KEY_ID, As>` to/from encoded data. For brevity, `As` inserts an additional +/// conversion (`From`) to avoid having to implement [`Encodable`] for many types. For example, +/// enums that are easily convertible to a u32 can have `As = u32` and rely on the existing encoding +/// for u32. +#[repr(transparent)] +pub(crate) struct Key<T, const KEY_ID: KeyId, As = T>(pub(crate) T, PhantomData<As>); + +impl<T, const KEY_ID: KeyId, As> From<T> for Key<T, KEY_ID, As> { + fn from(value: T) -> Self { + Self(value, PhantomData) + } +} + +impl<'a, T, const KEY_ID: KeyId, As, const N: usize> From<&'a [T; N]> for Key<&'a [T], KEY_ID, As> { + fn from(value: &'a [T; N]) -> Self { + Self(&value[..], PhantomData) + } +} + +impl<T, const KEY_ID: KeyId, As> Deref for Key<T, KEY_ID, As> { + type Target = T; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} + +impl<T, const KEY_ID: KeyId, As> DerefMut for Key<T, KEY_ID, As> { + fn deref_mut(&mut self) -> &mut Self::Target { + &mut self.0 + } +} + +impl<T: Default, const KEY_ID: KeyId, As> Default for Key<T, KEY_ID, As> { + fn default() -> Self { + Self(T::default(), PhantomData) + } +} + bitfield! { /// The op word that starts each NVKV operation. struct Op(u64) { diff --git a/drivers/gpu/nova-core/gsp/nvkv/encode.rs b/drivers/gpu/nova-core/gsp/nvkv/encode.rs index 6da81a371651..31ea5788e772 100644 --- a/drivers/gpu/nova-core/gsp/nvkv/encode.rs +++ b/drivers/gpu/nova-core/gsp/nvkv/encode.rs @@ -7,11 +7,153 @@ use super::{ Index, + Key, KeyId, Op, Opcode, // }; +/// A type that can encode itself into an [`Encoder`]. +pub(crate) trait Encodable { + /// Encodes `self` into `encoder`. + fn encode(&self, encoder: &mut Encoder) -> Result; +} + +/// Defines a struct together with its [`Encodable`] implementation. +/// +/// The implementation encodes each field in declaration order. Each field type must implement +/// [`Encodable`], which is done already for types like `Key<T, KEY_ID>`. +/// +/// # Examples +/// +/// ``` +/// nvkv_encode! { +/// struct Request { +/// id: Key<u32, 0x0001>, +/// name: Key<&'static [u8], 0x0002>, +/// } +/// } +/// ``` +macro_rules! nvkv_encode { + ( + $(#[$attr:meta])* + $vis:vis struct $name:ident { + $( + $(#[$field_attr:meta])* + $field_vis:vis $field:ident : $ty:ty + ),* $(,)? + } + ) => { + $(#[$attr])* + $vis struct $name { + $( + $(#[$field_attr])* + $field_vis $field: $ty, + )* + } + + impl $crate::gsp::nvkv::Encodable for $name { + #[inline(always)] + fn encode(&self, encoder: &mut $crate::gsp::nvkv::Encoder) -> ::kernel::error::Result { + $( $crate::gsp::nvkv::Encodable::encode(&self.$field, encoder)?; )* + Ok(()) + } + } + }; +} +pub(crate) use nvkv_encode; + +/// A value with a specific index that encodes under the NVKV key `KEY_ID`. +struct IndexedKey<T, const KEY_ID: KeyId> { + index: Index, + value: T, +} + +impl<T, const KEY_ID: KeyId> IndexedKey<T, KEY_ID> { + /// Creates a key with the given index and value. + pub(crate) fn new(index: Index, value: T) -> Self { + Self { index, value } + } +} + +impl<const KEY_ID: KeyId> Encodable for IndexedKey<u32, KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_u32(KEY_ID, self.index, self.value) + } +} + +impl<const KEY_ID: KeyId> Encodable for IndexedKey<u64, KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_u64(KEY_ID, self.index, self.value) + } +} + +impl<const KEY_ID: KeyId> Encodable for IndexedKey<&[u8], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array8(KEY_ID, self.index, self.value) + } +} + +impl<const KEY_ID: KeyId> Encodable for IndexedKey<&[u32], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array32(KEY_ID, self.index, self.value) + } +} + +impl<const KEY_ID: KeyId> Encodable for IndexedKey<&[u64], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array64(KEY_ID, self.index, self.value) + } +} + +impl<const N: usize, const KEY_ID: KeyId> Encodable for IndexedKey<[u8; N], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array8(KEY_ID, self.index, &self.value) + } +} + +impl<const N: usize, const KEY_ID: KeyId> Encodable for IndexedKey<[u32; N], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array32(KEY_ID, self.index, &self.value) + } +} + +impl<const N: usize, const KEY_ID: KeyId> Encodable for IndexedKey<[u64; N], KEY_ID> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + encoder.encode_array64(KEY_ID, self.index, &self.value) + } +} + +impl<T, const KEY_ID: KeyId, As> Encodable for Key<T, KEY_ID, As> +where + IndexedKey<As, KEY_ID>: Encodable, + As: From<T>, + T: Copy, +{ + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + IndexedKey::new(Index::new::<0>(), As::from(self.0)).encode(encoder) + } +} + +impl<T: Encodable> Encodable for Option<T> { + #[inline(always)] + fn encode(&self, encoder: &mut Encoder) -> Result { + if let Some(value) = self { + value.encode(encoder)?; + } + Ok(()) + } +} + /// An encoder for an NVKV stream. pub(crate) struct Encoder { backing: KVVec<u64>, @@ -242,4 +384,40 @@ fn encode_all_value_kinds() -> Result { Ok(()) } + + // Tests that encoding via the `nvkv_encode!` macro works correctly. + #[test] + fn encode_typed_struct() -> Result { + const U32_KEY: KeyId = 0x0001; + const U64_KEY: KeyId = 0x0002; + const NAME_KEY: KeyId = 0x0003; + const FIXED_KEY: KeyId = 0x0004; + const OPT_KEY: KeyId = 0x0005; + + nvkv_encode! { + struct TypedRequest { + a: Key<u32, { U32_KEY }>, + b: Key<u64, { U64_KEY }>, + name: Key<&'static [u8], { NAME_KEY }>, + fixed: Key<[u8; 4], { FIXED_KEY }>, + opt: Option<Key<u32, { OPT_KEY }>>, + } + } + + let request = TypedRequest { + a: 0x89ab_cdef.into(), + b: 0x0123_4567_89ab_cdef.into(), + name: b"name\0".into(), + fixed: [1u8, 2, 3, 4].into(), + opt: None, + }; + + let mut encoder = Encoder::new(); + request.encode(&mut encoder)?; + let encoded = encoder.finish(); + + assert_eq!(encoded.len(), 7); + + Ok(()) + } } -- 2.55.0
