Re: [PATCH v2 08/10] gpu: nova-core: convert falcon registers to kernel register macro

["Gary Guo" <gary@garyguo.net>]

On Fri Mar 20, 2026 at 7:52 PM GMT, John Hubbard wrote:
> On 3/20/26 10:38 AM, Joel Fernandes wrote:
>> Hi Alex,
>> 
>> On 3/20/2026 8:19 AM, Alexandre Courbot wrote:
>>>      /// Reset the controller, select the falcon core, and wait for memory scrubbing to complete.
>>> @@ -616,9 +462,10 @@ pub(crate) fn reset(&self, bar: &Bar0) -> Result {
>>>          self.hal.select_core(self, bar)?;
>>>          self.hal.reset_wait_mem_scrubbing(bar)?;
>>>  
>>> -        regs::NV_PFALCON_FALCON_RM::default()
>>> -            .set_value(bar.read(regs::NV_PMC_BOOT_0).into())
>>> -            .write(bar, &E::ID);
>>> +        bar.write(
>>> +            WithBase::of::<E>(),
>>> +            regs::NV_PFALCON_FALCON_RM::from(bar.read(regs::NV_PMC_BOOT_0).into_raw()),
>>> +        );
>>>  
>> 
>> Overall, I think the series is good improvement but I still feel this part is a
>> step back in readability, and we should come up with something better. I don't
>> think there's any chance anyone can memorize this syntax.
>
> I must reluctantly (because I know this conversation has gone very
> long, across so many versions) agree. That .write() statement is just
> brutal, and we will be relying on AI in order to even figure it out,
> I fear.
>
> I'd hoped that there were other, simpler forms to express this,
> is that not the case here?

It's on my radar to integrate `register!` and I/O projection (but of course, I
need to ship I/O projection first) to solve the relative register issue.

The idea is that instead of having an operation with all of `bar`, `E` and
`NV_PFALCON_FALCON_RM`, you first use projection (with a surface syntax that I
haven't considered yet) to go from `bar` to `View<'_, .., .E>` and then your
relative register becomes just a normal register on it.

Best,
Gary


>
> thanks,