gpu: nova-core: register: improve Debug implementation

Now that we have an internal rule to dispatch field information where
needed, use it to generate a better `Debug` implementation where the raw
hexadecimal value of the register is displayed, as well as the `Debug`
values of its individual fields.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20250718-nova-regs-v2-11-7b6a762aa1cd@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

drivers/gpu/nova-core/regs/macros.rs

@@ -122,16 +122,6 @@ macro_rules! register {
         #[derive(Clone, Copy, Default)]
         pub(crate) struct $name(u32);
 
-        // TODO[REGA]: display the raw hex value, then the value of all the fields. This requires
-        // matching the fields, which will complexify the syntax considerably...
-        impl ::core::fmt::Debug for $name {
-            fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
-                f.debug_tuple(stringify!($name))
-                    .field(&format_args!("0x{0:x}", &self.0))
-                    .finish()
-            }
-        }
-
         impl ::core::ops::BitOr for $name {
             type Output = Self;
 
@@ -171,6 +161,7 @@ fn from(reg: $name) -> u32 {
             ;
             )*
         });
+        register!(@debug $name { $($field;)* });
     };
 
     // Defines all the field getter/methods methods for `$name`.
@@ -316,6 +307,20 @@ pub(crate) fn [<set_ $field>](mut self, value: $to_type) -> Self {
         );
     };
 
+    // Generates the `Debug` implementation for `$name`.
+    (@debug $name:ident { $($field:ident;)* }) => {
+        impl ::core::fmt::Debug for $name {
+            fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
+                f.debug_struct(stringify!($name))
+                    .field("<raw>", &format_args!("{:#x}", &self.0))
+                $(
+                    .field(stringify!($field), &self.$field())
+                )*
+                    .finish()
+            }
+        }
+    };
+
     // Generates the IO accessors for a fixed offset register.
     (@io $name:ident @ $offset:expr) => {
         #[allow(dead_code)]