gpu: nova-core: register: use field type for Into implementation

The getter method of a field works with the field type, but its setter
expects the type of the register. This leads to an asymmetry in the
From/Into implementations required for a field with a dedicated type.
For instance, a field declared as

    pub struct ControlReg(u32) {
        3:0 mode as u8 ?=> Mode;
        ...
    }

currently requires the following implementations:

    impl TryFrom<u8> for Mode {
      ...
    }

    impl From<Mode> for u32 {
      ...
    }

Change this so the `From<Mode>` now needs to be implemented for `u8`,
i.e. the primitive type of the field. This is more consistent, and will
become a requirement once we start using the TryFrom/Into derive macros
to implement these automatically.

Reported-by: Edwin Peer <epeer@nvidia.com>
Closes: https://lore.kernel.org/rust-for-linux/F3853912-2C1C-4F9B-89B0-3168689F35B3@nvidia.com/
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Message-ID: <20251016151323.1201196-2-joelagnelf@nvidia.com>

1 files changed, 27 insertions, 11 deletions

diff --git a/drivers/gpu/nova-core/falcon.rs b/drivers/gpu/nova-core/falcon.rs
index 37e6298195e4..3f505b870601 100644
--- a/drivers/gpu/nova-core/falcon.rs
+++ b/drivers/gpu/nova-core/falcon.rs
@@ -22,11 +22,11 @@ mod hal;
 pub(crate) mod sec2;
 
 // TODO[FPRI]: Replace with `ToPrimitive`.
-macro_rules! impl_from_enum_to_u32 {
+macro_rules! impl_from_enum_to_u8 {
     ($enum_type:ty) => {
-        impl From<$enum_type> for u32 {
+        impl From<$enum_type> for u8 {
             fn from(value: $enum_type) -> Self {
-                value as u32
+                value as u8
             }
         }
     };
@@ -46,7 +46,7 @@ pub(crate) enum FalconCoreRev {
     Rev6 = 6,
     Rev7 = 7,
 }
-impl_from_enum_to_u32!(FalconCoreRev);
+impl_from_enum_to_u8!(FalconCoreRev);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for FalconCoreRev {
@@ -81,7 +81,7 @@ pub(crate) enum FalconCoreRevSubversion {
     Subversion2 = 2,
     Subversion3 = 3,
 }
-impl_from_enum_to_u32!(FalconCoreRevSubversion);
+impl_from_enum_to_u8!(FalconCoreRevSubversion);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for FalconCoreRevSubversion {
@@ -125,7 +125,7 @@ pub(crate) enum FalconSecurityModel {
     /// Also known as High-Secure, Privilege Level 3 or PL3.
     Heavy = 3,
 }
-impl_from_enum_to_u32!(FalconSecurityModel);
+impl_from_enum_to_u8!(FalconSecurityModel);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for FalconSecurityModel {
@@ -157,7 +157,7 @@ pub(crate) enum FalconModSelAlgo {
     #[default]
     Rsa3k = 1,
 }
-impl_from_enum_to_u32!(FalconModSelAlgo);
+impl_from_enum_to_u8!(FalconModSelAlgo);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for FalconModSelAlgo {
@@ -179,7 +179,7 @@ pub(crate) enum DmaTrfCmdSize {
     #[default]
     Size256B = 0x6,
 }
-impl_from_enum_to_u32!(DmaTrfCmdSize);
+impl_from_enum_to_u8!(DmaTrfCmdSize);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for DmaTrfCmdSize {
@@ -202,7 +202,6 @@ pub(crate) enum PeregrineCoreSelect {
     /// RISC-V core is active.
     Riscv = 1,
 }
-impl_from_enum_to_u32!(PeregrineCoreSelect);
 
 impl From<bool> for PeregrineCoreSelect {
     fn from(value: bool) -> Self {
@@ -213,6 +212,15 @@ impl From<bool> for PeregrineCoreSelect {
     }
 }
 
+impl From<PeregrineCoreSelect> for bool {
+    fn from(value: PeregrineCoreSelect) -> Self {
+        match value {
+            PeregrineCoreSelect::Falcon => false,
+            PeregrineCoreSelect::Riscv => true,
+        }
+    }
+}
+
 /// Different types of memory present in a falcon core.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) enum FalconMem {
@@ -236,7 +244,7 @@ pub(crate) enum FalconFbifTarget {
     /// Non-coherent system memory (System DRAM).
     NoncoherentSysmem = 2,
 }
-impl_from_enum_to_u32!(FalconFbifTarget);
+impl_from_enum_to_u8!(FalconFbifTarget);
 
 // TODO[FPRI]: replace with `FromPrimitive`.
 impl TryFrom<u8> for FalconFbifTarget {
@@ -263,7 +271,6 @@ pub(crate) enum FalconFbifMemType {
     /// Physical memory addresses.
     Physical = 1,
 }
-impl_from_enum_to_u32!(FalconFbifMemType);
 
 /// Conversion from a single-bit register field.
 impl From<bool> for FalconFbifMemType {
@@ -275,6 +282,15 @@ impl From<bool> for FalconFbifMemType {
     }
 }
 
+impl From<FalconFbifMemType> for bool {
+    fn from(value: FalconFbifMemType) -> Self {
+        match value {
+            FalconFbifMemType::Virtual => false,
+            FalconFbifMemType::Physical => true,
+        }
+    }
+}
+
 /// Type used to represent the `PFALCON` registers address base for a given falcon engine.
 pub(crate) struct PFalconBase(());