Merge tag 'nova-next-v6.16-2025-05-20' of https://gitlab.freedesktop.org/drm/nova into drm-next

Nova changes for v6.16

auxiliary:
  - bus abstractions
  - implementation for driver registration
  - add sample driver

drm:
  - implement __drm_dev_alloc()
  - DRM core infrastructure Rust abstractions
    - device, driver and registration
    - DRM IOCTL
    - DRM File
    - GEM object
  - IntoGEMObject rework
    - generically implement AlwaysRefCounted through IntoGEMObject
    - refactor unsound from_gem_obj() into as_ref()
    - refactor into_gem_obj() into as_raw()

driver-core:
  - merge topic/device-context-2025-04-17 from driver-core tree
  - implement Devres::access()
    - fix: doctest build under `!CONFIG_PCI`
  - accessor for Device::parent()
    - fix: conditionally expect `dead_code` for `parent()`
  - impl TryFrom<&Device> bus devices (PCI, platform)

nova-core:
  - remove completed Vec extentions from task list
  - register auxiliary device for nova-drm
  - derive useful traits for Chipset
  - add missing GA100 chipset
  - take &Device<Bound> in Gpu::new()
  - infrastructure to generate register definitions
  - fix register layout of NV_PMC_BOOT_0
  - move Firmware into own (Rust) module
  - fix: select AUXILIARY_BUS

nova-drm:
  - initial driver skeleton (depends on drm and auxiliary bus
    abstractions)
  - fix: select AUXILIARY_BUS

Rust (dependencies):
  - implement Opaque::zeroed()
  - implement Revocable::try_access_with()
  - implement Revocable::access()

From: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/aCxAf3RqQAXLDhAj@cassiopeiae

1 files changed, 29 insertions, 25 deletions

diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 4917cb34e2fe..08849d92c074 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -5,18 +5,17 @@
 //! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h)
 
 use crate::{
-    bindings, device, driver,
+    bindings, container_of, device, driver,
     error::{to_result, Result},
     of,
     prelude::*,
     str::CStr,
-    types::{ARef, ForeignOwnable, Opaque},
+    types::{ForeignOwnable, Opaque},
     ThisModule,
 };
 
 use core::{
     marker::PhantomData,
-    ops::Deref,
     ptr::{addr_of_mut, NonNull},
 };
 
@@ -184,31 +183,16 @@ pub struct Device<Ctx: device::DeviceContext = device::Normal>(
     PhantomData<Ctx>,
 );
 
-impl Device {
+impl<Ctx: device::DeviceContext> Device<Ctx> {
     fn as_raw(&self) -> *mut bindings::platform_device {
         self.0.get()
     }
 }
 
-impl Deref for Device<device::Core> {
-    type Target = Device;
-
-    fn deref(&self) -> &Self::Target {
-        let ptr: *const Self = self;
-
-        // CAST: `Device<Ctx>` is a transparent wrapper of `Opaque<bindings::platform_device>`.
-        let ptr = ptr.cast::<Device>();
-
-        // SAFETY: `ptr` was derived from `&self`.
-        unsafe { &*ptr }
-    }
-}
-
-impl From<&Device<device::Core>> for ARef<Device> {
-    fn from(dev: &Device<device::Core>) -> Self {
-        (&**dev).into()
-    }
-}
+// SAFETY: `Device` is a transparent wrapper of a type that doesn't depend on `Device`'s generic
+// argument.
+kernel::impl_device_context_deref!(unsafe { Device });
+kernel::impl_device_context_into_aref!(Device);
 
 // SAFETY: Instances of `Device` are always reference-counted.
 unsafe impl crate::types::AlwaysRefCounted for Device {
@@ -223,8 +207,8 @@ unsafe impl crate::types::AlwaysRefCounted for Device {
     }
 }
 
-impl AsRef<device::Device> for Device {
-    fn as_ref(&self) -> &device::Device {
+impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
+    fn as_ref(&self) -> &device::Device<Ctx> {
         // SAFETY: By the type invariant of `Self`, `self.as_raw()` is a pointer to a valid
         // `struct platform_device`.
         let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };
@@ -234,6 +218,26 @@ impl AsRef<device::Device> for Device {
     }
 }
 
+impl<Ctx: device::DeviceContext> TryFrom<&device::Device<Ctx>> for &Device<Ctx> {
+    type Error = kernel::error::Error;
+
+    fn try_from(dev: &device::Device<Ctx>) -> Result<Self, Self::Error> {
+        // SAFETY: By the type invariant of `Device`, `dev.as_raw()` is a valid pointer to a
+        // `struct device`.
+        if !unsafe { bindings::dev_is_platform(dev.as_raw()) } {
+            return Err(EINVAL);
+        }
+
+        // SAFETY: We've just verified that the bus type of `dev` equals
+        // `bindings::platform_bus_type`, hence `dev` must be embedded in a valid
+        // `struct platform_device` as guaranteed by the corresponding C code.
+        let pdev = unsafe { container_of!(dev.as_raw(), bindings::platform_device, dev) };
+
+        // SAFETY: `pdev` is a valid pointer to a `struct platform_device`.
+        Ok(unsafe { &*pdev.cast() })
+    }
+}
+
 // SAFETY: A `Device` is always reference-counted and can be released from any thread.
 unsafe impl Send for Device {}