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.
The next patch will make use of it to convert all falcon registers to
the kernel register macro.
The macro is unused in this patch: it is introduced ahead-of-time to
avoid diff mingling in the next patch that would make it difficult to
review.
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/gpu/nova-core/falcon.rs | 82 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 82 insertions(+)
diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
index 5a4f7fc85160..5221e4476f90 100644
--- a/drivers/gpu/nova-core/falcon.rs
+++ b/drivers/gpu/nova-core/falcon.rs
@@ -54,6 +54,88 @@ fn from(value: $enum_type) -> Self {
};
}
+/// Creates an enum type associated to a `Bounded`, with a `From` conversion to the associated
+/// `Bounded` and either a `TryFrom` or `From` converting from the associated `Bounded`.
+// TODO[FPRI]: This is a temporary solution to be replaced with the corresponding derive macros
+// once they land.
+#[expect(unused)]
+macro_rules! bounded_enum {
+ (
+ $(#[doc = $enum_doc:expr])*
+ enum $enum_type:ident with $from_impl:ident<Bounded<$width:ty, $length:literal>> {
+ $( $(#[doc = $variant_doc:expr])* $variant:ident = $value:expr),* $(,)*
+ }
+ ) => {
+ $(#[doc = $enum_doc])*
+ #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+ pub(crate) enum $enum_type {
+ $(
+ $(#[doc = $variant_doc])*
+ $variant = $value
+ ),*
+ }
+
+ impl From<$enum_type> for Bounded<$width, $length> {
+ fn from(value: $enum_type) -> Self {
+ match value {
+ $($enum_type::$variant => Bounded::<$width, _>::new::<$value>()),*
+ }
+ }
+ }
+
+ bounded_enum!(@impl_from $enum_type with $from_impl<Bounded<$width, $length>> {
+ $($variant = $value),*
+ });
+ };
+
+ // `TryFrom` implementation from associated `Bounded` to enum type.
+ (@impl_from $enum_type:ident with TryFrom<Bounded<$width:ty, $length:literal>> {
+ $($variant:ident = $value:expr),* $(,)*
+ }) => {
+ impl TryFrom<Bounded<$width, $length>> for $enum_type {
+ type Error = Error;
+
+ fn try_from(value: Bounded<$width, $length>) -> Result<Self> {
+ match value.get() {
+ $(
+ $value => Ok($enum_type::$variant),
+ )*
+ _ => Err(EINVAL),
+ }
+ }
+ }
+ };
+
+ // `From` implementation from associated `Bounded` to enum type. Triggers a `build_error` if
+ // all possible values of the `Bounded` are not covered by the enum type.
+ (@impl_from $enum_type:ident with From<Bounded<$width:ty, $length:literal>> {
+ $($variant:ident = $value:expr),* $(,)*
+ }) => {
+ impl From<Bounded<$width, $length>> for $enum_type {
+ fn from(value: Bounded<$width, $length>) -> Self {
+ $(
+ // Ensure all enum values fit into the `Bounded` type.
+ const { assert!(
+ $value < (1 << $length),
+ "Enum variant doesn't fit into assigned `Bounded` type."
+ ); }
+ )*
+
+ // Makes the compiler optimizer aware of the possible range of values.
+ let value = value.get() & ((1 << $length) - 1);
+ match value {
+ $(
+ $value => $enum_type::$variant,
+ )*
+ // We land here if the match didn't cover all possible values for the
+ // `Bounded`.
+ _ => build_error!("Enum doesn't cover all values of the `Bounded` type."),
+ }
+ }
+ }
+ }
+}
+
/// Revision number of a falcon core, used in the [`crate::regs::NV_PFALCON_FALCON_HWCFG1`]
/// register.
#[repr(u8)]
--
2.53.0On Mon Mar 23, 2026 at 11:07 AM GMT, Alexandre Courbot wrote:
> 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.
>
> The next patch will make use of it to convert all falcon registers to
> the kernel register macro.
>
> The macro is unused in this patch: it is introduced ahead-of-time to
> avoid diff mingling in the next patch that would make it difficult to
> review.
>
> Reviewed-by: Gary Guo <gary@garyguo.net>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
> drivers/gpu/nova-core/falcon.rs | 82 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 82 insertions(+)
>
> diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
> index 5a4f7fc85160..5221e4476f90 100644
> --- a/drivers/gpu/nova-core/falcon.rs
> +++ b/drivers/gpu/nova-core/falcon.rs
> @@ -54,6 +54,88 @@ fn from(value: $enum_type) -> Self {
> };
> }
>
> +/// Creates an enum type associated to a `Bounded`, with a `From` conversion to the associated
> +/// `Bounded` and either a `TryFrom` or `From` converting from the associated `Bounded`.
> +// TODO[FPRI]: This is a temporary solution to be replaced with the corresponding derive macros
> +// once they land.
> +#[expect(unused)]
> +macro_rules! bounded_enum {
> + (
> + $(#[doc = $enum_doc:expr])*
> + enum $enum_type:ident with $from_impl:ident<Bounded<$width:ty, $length:literal>> {
> + $( $(#[doc = $variant_doc:expr])* $variant:ident = $value:expr),* $(,)*
> + }
> + ) => {
> + $(#[doc = $enum_doc])*
> + #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
> + pub(crate) enum $enum_type {
> + $(
> + $(#[doc = $variant_doc])*
> + $variant = $value
> + ),*
> + }
> +
> + impl From<$enum_type> for Bounded<$width, $length> {
> + fn from(value: $enum_type) -> Self {
> + match value {
> + $($enum_type::$variant => Bounded::<$width, _>::new::<$value>()),*
Hi Alex,
This looks exactly the same as the last version, without out the {} and MAX..
change made (which you mentioned in the cover letter).
Best,
Gary
> + }
> + }
> + }
> +
> + bounded_enum!(@impl_from $enum_type with $from_impl<Bounded<$width, $length>> {
> + $($variant = $value),*
> + });
> + };
> +
> + // `TryFrom` implementation from associated `Bounded` to enum type.
> + (@impl_from $enum_type:ident with TryFrom<Bounded<$width:ty, $length:literal>> {
> + $($variant:ident = $value:expr),* $(,)*
> + }) => {
> + impl TryFrom<Bounded<$width, $length>> for $enum_type {
> + type Error = Error;
> +
> + fn try_from(value: Bounded<$width, $length>) -> Result<Self> {
> + match value.get() {
> + $(
> + $value => Ok($enum_type::$variant),
> + )*
> + _ => Err(EINVAL),
> + }
> + }
> + }
> + };
> +
> + // `From` implementation from associated `Bounded` to enum type. Triggers a `build_error` if
> + // all possible values of the `Bounded` are not covered by the enum type.
> + (@impl_from $enum_type:ident with From<Bounded<$width:ty, $length:literal>> {
> + $($variant:ident = $value:expr),* $(,)*
> + }) => {
> + impl From<Bounded<$width, $length>> for $enum_type {
> + fn from(value: Bounded<$width, $length>) -> Self {
> + $(
> + // Ensure all enum values fit into the `Bounded` type.
> + const { assert!(
> + $value < (1 << $length),
> + "Enum variant doesn't fit into assigned `Bounded` type."
> + ); }
> + )*
> +
> + // Makes the compiler optimizer aware of the possible range of values.
> + let value = value.get() & ((1 << $length) - 1);
> + match value {
> + $(
> + $value => $enum_type::$variant,
> + )*
> + // We land here if the match didn't cover all possible values for the
> + // `Bounded`.
> + _ => build_error!("Enum doesn't cover all values of the `Bounded` type."),
> + }
> + }
> + }
> + }
> +}
> +
> /// Revision number of a falcon core, used in the [`crate::regs::NV_PFALCON_FALCON_HWCFG1`]
> /// register.
> #[repr(u8)]
On Mon Mar 23, 2026 at 9:43 PM JST, Gary Guo wrote:
> On Mon Mar 23, 2026 at 11:07 AM GMT, Alexandre Courbot wrote:
>> 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.
>>
>> The next patch will make use of it to convert all falcon registers to
>> the kernel register macro.
>>
>> The macro is unused in this patch: it is introduced ahead-of-time to
>> avoid diff mingling in the next patch that would make it difficult to
>> review.
>>
>> Reviewed-by: Gary Guo <gary@garyguo.net>
>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>> ---
>> drivers/gpu/nova-core/falcon.rs | 82 +++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 82 insertions(+)
>>
>> diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
>> index 5a4f7fc85160..5221e4476f90 100644
>> --- a/drivers/gpu/nova-core/falcon.rs
>> +++ b/drivers/gpu/nova-core/falcon.rs
>> @@ -54,6 +54,88 @@ fn from(value: $enum_type) -> Self {
>> };
>> }
>>
>> +/// Creates an enum type associated to a `Bounded`, with a `From` conversion to the associated
>> +/// `Bounded` and either a `TryFrom` or `From` converting from the associated `Bounded`.
>> +// TODO[FPRI]: This is a temporary solution to be replaced with the corresponding derive macros
>> +// once they land.
>> +#[expect(unused)]
>> +macro_rules! bounded_enum {
>> + (
>> + $(#[doc = $enum_doc:expr])*
>> + enum $enum_type:ident with $from_impl:ident<Bounded<$width:ty, $length:literal>> {
>> + $( $(#[doc = $variant_doc:expr])* $variant:ident = $value:expr),* $(,)*
>> + }
>> + ) => {
>> + $(#[doc = $enum_doc])*
>> + #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
>> + pub(crate) enum $enum_type {
>> + $(
>> + $(#[doc = $variant_doc])*
>> + $variant = $value
>> + ),*
>> + }
>> +
>> + impl From<$enum_type> for Bounded<$width, $length> {
>> + fn from(value: $enum_type) -> Self {
>> + match value {
>> + $($enum_type::$variant => Bounded::<$width, _>::new::<$value>()),*
>
> Hi Alex,
>
> This looks exactly the same as the last version, without out the {} and MAX..
> change made (which you mentioned in the cover letter).
I'm so sorry. I mistakenly squashed the fixup commit into the next
commit instead of this one. I will resend after hearing back from Danilo
about where the macro should reside.
On Mon Mar 23, 2026 at 12:07 PM CET, Alexandre Courbot wrote: > 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. > > The next patch will make use of it to convert all falcon registers to > the kernel register macro. > > The macro is unused in this patch: it is introduced ahead-of-time to > avoid diff mingling in the next patch that would make it difficult to > review. > > Reviewed-by: Gary Guo <gary@garyguo.net> > Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> > --- > drivers/gpu/nova-core/falcon.rs | 82 +++++++++++++++++++++++++++++++++++++++++ Why does this live in falcon.rs?
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