rust: device: introduce device::CoreInternal

Introduce an internal device context, which is semantically equivalent
to the Core device context, but reserved for bus abstractions.

This allows implementing methods for the Device type, which are limited
to be used within the core context of bus abstractions, i.e. restrict
the availability for drivers.

Link: https://lore.kernel.org/r/20250621195118.124245-2-dakr@kernel.org
[ Rename device::Internal to device::CoreInternal. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 665f5ceadecc..6b8acee4a378 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -261,6 +261,10 @@ pub struct Normal;
 /// any of the bus callbacks, such as `probe()`.
 pub struct Core;
 
+/// Semantically the same as [`Core`] but reserved for internal usage of the corresponding bus
+/// abstraction.
+pub struct CoreInternal;
+
 /// The [`Bound`] context is the context of a bus specific device reference when it is guaranteed to
 /// be bound for the duration of its lifetime.
 pub struct Bound;
@@ -270,11 +274,13 @@ mod private {
 
     impl Sealed for super::Bound {}
     impl Sealed for super::Core {}
+    impl Sealed for super::CoreInternal {}
     impl Sealed for super::Normal {}
 }
 
 impl DeviceContext for Bound {}
 impl DeviceContext for Core {}
+impl DeviceContext for CoreInternal {}
 impl DeviceContext for Normal {}
 
 /// # Safety
@@ -316,6 +322,13 @@ macro_rules! impl_device_context_deref {
         // `__impl_device_context_deref!`.
         ::kernel::__impl_device_context_deref!(unsafe {
             $device,
+            $crate::device::CoreInternal => $crate::device::Core
+        });
+
+        // SAFETY: This macro has the exact same safety requirement as
+        // `__impl_device_context_deref!`.
+        ::kernel::__impl_device_context_deref!(unsafe {
+            $device,
             $crate::device::Core => $crate::device::Bound
         });
 
@@ -345,6 +358,7 @@ macro_rules! __impl_device_context_into_aref {
 #[macro_export]
 macro_rules! impl_device_context_into_aref {
     ($device:tt) => {
+        ::kernel::__impl_device_context_into_aref!($crate::device::CoreInternal, $device);
         ::kernel::__impl_device_context_into_aref!($crate::device::Core, $device);
         ::kernel::__impl_device_context_into_aref!($crate::device::Bound, $device);
     };