drm: nova: Add DRM registration data

Currently the nova-drm stub driver doesn't really interact with a real
device, so it doesn't have any registration data and has no way to call
into nova-core.

To allow for this add a DrmRegData type which will hold a
NovaCoreApiHandle for the NovaCoreApi associated with the auxbus device.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
Suggested-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260909064506.910162-4-apopple@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

drivers/gpu/drm/nova/driver.rs

@@ -18,6 +18,11 @@
 use crate::file::File;
 use crate::gem::NovaObject;
 
+use nova_core::api::{
+    NovaCoreApi,
+    NovaCoreApiHandle, //
+};
+
 pub(crate) struct NovaDriver;
 
 pub(crate) struct Nova<'bound> {
@@ -26,6 +31,12 @@ pub(crate) struct Nova<'bound> {
     _reg: drm::Registration<'bound, NovaDriver>,
 }
 
+/// DRM registration data, accessible from ioctl handlers via the registration guard.
+pub(crate) struct DrmRegData<'bound> {
+    #[expect(unused)]
+    pub(crate) api: NovaCoreApiHandle<'bound>,
+}
+
 /// Convienence type alias for the DRM device type for this driver
 pub(crate) type NovaDevice<Ctx = drm::Normal> = drm::Device<NovaDriver, Ctx>;
 
@@ -59,9 +70,12 @@ fn probe<'bound>(
         _info: &'bound Self::IdInfo,
     ) -> impl PinInit<Self::Data<'bound>, Error> + 'bound {
         let drm = drm::UnregisteredDevice::<Self>::new(adev, Ok(()))?;
+        let reg_data = DrmRegData {
+            api: NovaCoreApi::of(adev)?,
+        };
         // SAFETY: `reg` is stored in `Nova` and dropped when the driver is unbound; it is
         // never forgotten.
-        let reg = unsafe { drm::Registration::new(adev.as_ref(), drm, (), 0)? };
+        let reg = unsafe { drm::Registration::new(adev.as_ref(), drm, reg_data, 0)? };
 
         Ok(Nova {
             drm: reg.device().into(),
@@ -73,7 +87,7 @@ fn probe<'bound>(
 #[vtable]
 impl drm::Driver for NovaDriver {
     type Data = ();
-    type RegistrationData<'a> = ();
+    type RegistrationData<'a> = DrmRegData<'a>;
     type File = File;
     type Object = gem::Object<NovaObject>;
     type ParentDevice<Ctx: DeviceContext> = auxiliary::Device<Ctx>;

drivers/gpu/drm/nova/file.rs

@@ -1,6 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use crate::driver::{NovaDevice, NovaDriver};
+use crate::driver::{
+    DrmRegData,
+    NovaDevice,
+    NovaDriver, //
+};
 use crate::gem::NovaObject;
 use kernel::{
     alloc::flags::*,
@@ -30,7 +34,7 @@ impl File {
     /// IOCTL: get_param: Query GPU / driver metadata.
     pub(crate) fn get_param(
         dev: &NovaDevice<Registered>,
-        _reg_data: &(),
+        _reg_data: &DrmRegData<'_>,
         getparam: &mut uapi::drm_nova_getparam,
         _file: &drm::File<File>,
     ) -> Result<u32> {
@@ -50,7 +54,7 @@ pub(crate) fn get_param(
     /// IOCTL: gem_create: Create a new DRM GEM object.
     pub(crate) fn gem_create(
         dev: &NovaDevice<Registered>,
-        _reg_data: &(),
+        _reg_data: &DrmRegData<'_>,
         req: &mut uapi::drm_nova_gem_create,
         file: &drm::File<File>,
     ) -> Result<u32> {
@@ -64,7 +68,7 @@ pub(crate) fn gem_create(
     /// IOCTL: gem_info: Query GEM metadata.
     pub(crate) fn gem_info(
         _dev: &NovaDevice<Registered>,
-        _reg_data: &(),
+        _reg_data: &DrmRegData<'_>,
         req: &mut uapi::drm_nova_gem_info,
         file: &drm::File<File>,
     ) -> Result<u32> {