On Wed Aug 12, 2026 at 3:48 PM BST, Alexandre Courbot wrote:
> On Thu Aug 6, 2026 at 1:35 AM JST, Gary Guo wrote:
>> -/// Type used to represent the `PFALCON` registers address base for a given
>> falcon engine.
>> -pub(crate) struct PFalconBase(());
>> +/// Type used to represent the `PFALCON` registers.
>> +#[repr(align(4))]
>> +#[derive(FromBytes, IntoBytes)]
>> +pub(crate) struct PFalconRegisters([u8; SZ_4K]);
>>
>> -/// Type used to represent the `PFALCON2` registers address base for a
>> given falcon engine.
>> -pub(crate) struct PFalcon2Base(());
>> +/// Type used to represent the `PFALCON2` registers.
>> +#[repr(align(4))]
>> +#[derive(FromBytes, IntoBytes)]
>> +pub(crate) struct PFalcon2Registers([u8; SZ_4K]);
>>
>> /// Trait defining the parameters of a given Falcon engine.
>> ///
>> /// Each engine provides one base for `PFALCON` and `PFALCON2` registers.
>> -pub(crate) trait FalconEngine:
>> - Send + Sync + RegisterBase<PFalconBase> + RegisterBase<PFalcon2Base> +
>> Sized
>> -{
>> +pub(crate) trait FalconEngine: Send + Sync + Sized {
>> + fn pfalcon(io: Bar0<'_>) -> Mmio<'_, PFalconRegisters>;
>> + fn pfalcon2(io: Bar0<'_>) -> Mmio<'_, PFalcon2Registers>;
>
> Remember on v1 when we contemplated using associated consts? Turns out
> we can with this version:
>
> // Need a better name, but you get the idea.
> pub(crate) type PFalconRegs = OffsetLoc<NovaRegisters, PFalconRegisters>;
> pub(crate) type PFalcon2Regs = OffsetLoc<NovaRegisters,
> PFalcon2Registers>;
>
> pub(crate) trait FalconEngine: Send + Sync + Sized {
> const PFALCON: PFalconRegs;
> const PFALCON2: PFalcon2Regs;
> }
>
> ... and make `Falcon::new` call `io_project` directly, and it works! At
> the cost of importing `OffsetLoc` in `falcon.rs`, but that removes ~30
> LoCs in total, and I'm not sure `OffsetLoc` should be hidden anyway.
Originally I want the type of consts created by `register!()` to be considered
as implementation detail and thus ideally not to be named by the user. To user I
want them to treat it as just `impl IoLoc<>`.
However, thinking about this again, I think we might be able to have a single
type for all registers after all the cleanups, so it'd make sense to make this
public API. However, I do want a better name than `OffsetLoc` if we're going to
make this use case supported, though.
Best,
Gary
>
>> }
>>
>> /// Represents a portion of the firmware to be loaded into a particular
>> memory (e.g. IMEM or DMEM)
>> @@ -358,6 +361,8 @@ pub(crate) struct Falcon<'a, E: FalconEngine> {
>> hal: KBox<dyn FalconHal<E>>,
>> dev: &'a device::Device<device::Bound>,
>> bar: Bar0<'a>,
>> + pub(crate) pfalcon: Mmio<'a, PFalconRegisters>,
>> + pfalcon2: Mmio<'a, PFalcon2Registers>,
>> }
>>
