Nouveau - Nov 2025 - [PATCH v6 3/4] gpu: nova-core: make Architecture behave as a u8 type

This allows Architecture to be passed into register!() and bitfield!()
macro calls. That in turn requires a default implementation for
Architecture.

This simplifies transforming BOOT0 (and later, BOOT42) register values
into GPU architectures.

Cc: Danilo Krummrich <dakr at kernel.org>
Cc: Timur Tabi <ttabi at nvidia.com>
Suggested-by: Alexandre Courbot <acourbot at nvidia.com>
Signed-off-by: John Hubbard <jhubbard at nvidia.com>
---
 drivers/gpu/nova-core/gpu.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index acf564fee9c8..94a6054bab95 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -122,8 +122,10 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>)
-> fmt::Result {
 }
 
 /// Enum representation of the GPU generation.
-#[derive(fmt::Debug)]
+#[derive(fmt::Debug, Default, Copy, Clone)]
+#[repr(u8)]
 pub(crate) enum Architecture {
+    #[default]
     Turing = 0x16,
     Ampere = 0x17,
     Ada = 0x19,
@@ -142,6 +144,13 @@ fn try_from(value: u8) -> Result<Self> {
     }
 }
 
+impl From<Architecture> for u8 {
+    fn from(value: Architecture) -> Self {
+        // CAST: `Architecture` is `repr(u8)`, so this cast is always lossless.
+        value as u8
+    }
+}
+
 pub(crate) struct Revision {
     pub(crate) major: u8,
     pub(crate) minor: u8,
-- 
2.51.2

On Fri, 2025-11-07 at 20:39 -0800, John Hubbard wrote:
> ?/// Enum representation of the GPU generation.
> -#[derive(fmt::Debug)]
> +#[derive(fmt::Debug, Default, Copy, Clone)]
> +#[repr(u8)]
> ?pub(crate) enum Architecture {
> +??? #[default]
> ???? Turing = 0x16,
> ???? Ampere = 0x17,
> ???? Ada = 0x19,
> @@ -142,6 +144,13 @@ fn try_from(value: u8) -> Result<Self> {
> ???? }
> ?}
Does it make sense to designate a default Architecture?  Turing is not a
fallback for Ampere --
you can't boot an Ampere with Turing's HAL.  Also, we don't even
make Turing cards any more, so
over time, Turing will be less and less common.