Re: [PATCH FOR REFERENCE v8 10/10] gpu: nova-core: use the kernel `register!` macro

[John Hubbard <jhubbard@nvidia.com>]

On 3/9/26 8:43 AM, Joel Fernandes wrote:
> 
> On 3/9/2026 11:14 AM, Alexandre Courbot wrote:
>>
>> @@ -797,26 +792,30 @@ pub(crate) fn start(&self, bar: &Bar0) -> Result<()> {
>>      /// Writes values to the mailbox registers if provided.
>>      pub(crate) fn write_mailboxes(&self, bar: &Bar0, mbox0: Option<u32>, mbox1: Option<u32>) {
>>          if let Some(mbox0) = mbox0 {
>> -            regs::NV_PFALCON_FALCON_MAILBOX0::default()
>> -                .set_value(mbox0)
>> -                .write(bar, &E::ID);
>> +            bar.write(
>> +                WithBase::of::<E>(),
>> +                regs::NV_PFALCON_FALCON_MAILBOX0::zeroed().with_value(mbox0),
>> +            );
>>          }
>>  
>>          if let Some(mbox1) = mbox1 {
>> -            regs::NV_PFALCON_FALCON_MAILBOX1::default()
>> -                .set_value(mbox1)
>> -                .write(bar, &E::ID);
>> +            bar.write(
>> +                WithBase::of::<E>(),
>> +                regs::NV_PFALCON_FALCON_MAILBOX1::zeroed().with_value(mbox1),
>> +            );
>>          }
>>      }
> 
> TBH, this is quite a readability hit, the previous was much more readable IMHO.

Yes, I think so too, except that "WithBase::of::<E>" makes a lot more
sense on-screen, than "&E::ID". The latter just looks quite random,
so this part is an improvement.

Let's break down the remaining troublesome part a bit:

    regs::NV_PFALCON_FALCON_MAILBOX1::zeroed().with_value(mbox1)

* "regs::" can be omitted with a "use" statement, right?

* ::zeroed() maybe should be the default behavior here, and then
  it could also be omitted?

* .with_value(mbox1) I'm sure this is necessary, but the construction
  is unfortunately much less clear than .write(value)! Thoughts?


thanks,
-- 
John Hubbard