[PATCH RFC v2 1/3] gpu: nova-core: register: use field type for Into implementation

[Alexandre Courbot <acourbot@nvidia.com>]

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>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/falcon.rs      | 38 +++++++++++++++++++++++++-----------
 drivers/gpu/nova-core/regs/macros.rs | 10 +++++-----
 2 files changed, 32 insertions(+), 16 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 @@
 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 @@ fn from(value: bool) -> Self {
     }
 }
 
+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 @@ fn from(value: bool) -> Self {
     }
 }
 
+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(());
 
diff --git a/drivers/gpu/nova-core/regs/macros.rs b/drivers/gpu/nova-core/regs/macros.rs
index 754c14ee7f40..73811a115762 100644
--- a/drivers/gpu/nova-core/regs/macros.rs
+++ b/drivers/gpu/nova-core/regs/macros.rs
@@ -482,7 +482,7 @@ impl $name {
         register!(
             @leaf_accessor $name $hi:$lo $field
             { |f| <$into_type>::from(if f != 0 { true } else { false }) }
-            $into_type => $into_type $(, $comment)?;
+            bool $into_type => $into_type $(, $comment)?;
         );
     };
 
@@ -499,7 +499,7 @@ impl $name {
             $(, $comment:literal)?;
     ) => {
         register!(@leaf_accessor $name $hi:$lo $field
-            { |f| <$try_into_type>::try_from(f as $type) } $try_into_type =>
+            { |f| <$try_into_type>::try_from(f as $type) } $type $try_into_type =>
             ::core::result::Result<
                 $try_into_type,
                 <$try_into_type as ::core::convert::TryFrom<$type>>::Error
@@ -513,7 +513,7 @@ impl $name {
             $(, $comment:literal)?;
     ) => {
         register!(@leaf_accessor $name $hi:$lo $field
-            { |f| <$into_type>::from(f as $type) } $into_type => $into_type $(, $comment)?;);
+            { |f| <$into_type>::from(f as $type) } $type $into_type => $into_type $(, $comment)?;);
     };
 
     // Shortcut for non-boolean fields defined without the `=>` or `?=>` syntax.
@@ -527,7 +527,7 @@ impl $name {
     // Generates the accessor methods for a single field.
     (
         @leaf_accessor $name:ident $hi:tt:$lo:tt $field:ident
-            { $process:expr } $to_type:ty => $res_type:ty $(, $comment:literal)?;
+            { $process:expr } $prim_type:tt $to_type:ty => $res_type:ty $(, $comment:literal)?;
     ) => {
         ::kernel::macros::paste!(
         const [<$field:upper _RANGE>]: ::core::ops::RangeInclusive<u8> = $lo..=$hi;
@@ -559,7 +559,7 @@ pub(crate) fn $field(self) -> $res_type {
         pub(crate) fn [<set_ $field>](mut self, value: $to_type) -> Self {
             const MASK: u32 = $name::[<$field:upper _MASK>];
             const SHIFT: u32 = $name::[<$field:upper _SHIFT>];
-            let value = (u32::from(value) << SHIFT) & MASK;
+            let value = (u32::from($prim_type::from(value)) << SHIFT) & MASK;
             self.0 = (self.0 & !MASK) | value;
 
             self

-- 
2.51.0