rust/kernel/drm/drv.rs

@@ -13,7 +13,8 @@ use crate::{
         kms::{
             KmsImpl,
             private::KmsImpl as KmsImplPrivate,
-            KmsDriver
+            KmsDriver,
+            ModeConfigInfo,
         }
     },
     device,
@@ -129,6 +130,17 @@ pub struct AllocOps {
 pub trait AllocImpl: Sealed + drm::gem::IntoGEMObject {
     /// The C callback operations for this memory manager.
     const ALLOC_OPS: AllocOps;
+
+    /// Setup the fbdev implementation for a KMS driver using this [`AllocImpl`].
+    ///
+    /// # Safety
+    ///
+    /// This function must only be called once immediately after registration by the DRM crate.
+    #[cfg(CONFIG_DRM_FBDEV_EMULATION = "y")]
+    unsafe fn setup_fbdev(
+        drm: &drm::device::Device<Self::Driver>,
+        mode_config_info: &ModeConfigInfo
+    );
 }
 
 /// The DRM `Driver` trait.
@@ -145,7 +157,7 @@ pub trait Driver {
     /// The type used to manage memory for this driver.
     ///
     /// Should be either `drm::gem::Object<T>` or `drm::gem::shmem::Object<T>`.
-    type Object: AllocImpl;
+    type Object: AllocImpl<Driver = Self> where Self: Sized;
 
     /// The type used to represent a DRM File (client)
     type File: drm::file::DriverFile;
@@ -190,9 +202,12 @@ impl<T: Driver> Registration<T> {
             return Err(Error::from_errno(ret));
         }
 
-        if let Some(ref info) = mode_config_info {
-            // SAFETY: We just registered the device above
-            unsafe { T::Kms::setup_fbdev(&drm, info) };
+        #[cfg(CONFIG_DRM_FBDEV_EMULATION = "y")]
+        if has_kms {
+            if let Some(ref info) = mode_config_info {
+                // SAFETY: We just registered the device above, and this is within the DRM create
+                unsafe { T::Object::setup_fbdev(&drm, info) };
+            }
         }
 
         Ok(Self(drm))

rust/kernel/drm/gem/mod.rs

@@ -10,7 +10,7 @@ pub mod shmem;
 use crate::{
     alloc::flags::*,
     bindings,
-    drm::{device, drv, file},
+    drm::{device, drv, file, kms},
     error::{to_result, Result},
     prelude::*,
 };
@@ -301,6 +301,21 @@ impl<T: DriverObject> drv::AllocImpl for Object<T> {
         dumb_create: None,
         dumb_map_offset: None,
     };
+
+    #[cfg(CONFIG_DRM_FBDEV_EMULATION = "y")]
+    #[inline]
+    unsafe fn setup_fbdev(
+        drm: &device::Device<T::Driver>,
+        mode_config_info: &kms::ModeConfigInfo
+    ) {
+        // SAFETY:
+        // - This implementation of `AllocImpl` is proof that this driver is using the GEM dma
+        //   helpers.
+        // - `as_raw()` always returns a pointer to an initialized DRM device.
+        // - Our safety contract ensures that `drm` was just registered, and that we're being called
+        //   from the DRM crate
+        unsafe { bindings::drm_fbdev_dma_setup(drm.as_raw(), mode_config_info.preferred_depth) };
+    }
 }
 
 /// A reference-counted shared reference to a base GEM object.

rust/kernel/drm/gem/shmem.rs

@@ -4,7 +4,7 @@
 //!
 //! C header: [`include/linux/drm/drm_gem_shmem_helper.h`](../../../../include/linux/drm/drm_gem_shmem_helper.h)
 
-use crate::drm::{device, drv, gem};
+use crate::drm::{device, drv, gem, kms};
 use crate::{
     error::{from_err_ptr, to_result},
     prelude::*,
@@ -277,6 +277,21 @@ impl<T: DriverObject> drv::AllocImpl for Object<T> {
         dumb_create: Some(bindings::drm_gem_shmem_dumb_create),
         dumb_map_offset: None,
     };
+
+    #[cfg(CONFIG_DRM_FBDEV_EMULATION = "y")]
+    #[inline]
+    unsafe fn setup_fbdev(
+        drm: &device::Device<T::Driver>,
+        mode_config_info: &kms::ModeConfigInfo
+    ) {
+        // SAFETY:
+        // - This implementation of `AllocImpl` is proof that this driver is using the GEM shmem
+        //   helpers.
+        // - `as_raw()` always returns a pointer to an initialized DRM device.
+        // - Our safety contract ensures that `drm` was just registered, and that we're being called
+        //   from the DRM crate.
+        unsafe { bindings::drm_fbdev_shmem_setup(drm.as_raw(), mode_config_info.preferred_depth) };
+    }
 }
 
 /// A virtual mapping for a shmem-backed GEM object in kernel address space.

rust/kernel/drm/kms.rs

@@ -6,14 +6,13 @@ pub mod atomic;
 pub mod connector;
 pub mod crtc;
 pub mod encoder;
-pub mod fbdev;
 pub mod framebuffer;
 pub mod plane;
 pub mod vblank;
 
 use crate::{
     drm::{
-        drv::Driver,
+        drv::{Driver, AllocImpl},
         device::Device
     },
     device,
@@ -67,15 +66,6 @@ pub(crate) mod private {
         unsafe fn setup_kms(drm: &Device<Self::Driver>) -> Result<ModeConfigInfo> {
             build_error::build_error("This should never be reachable")
         }
-
-        /// The callback for setting up fbdev emulation on a KMS device.
-        ///
-        /// # Safety
-        ///
-        /// `drm` must be registered.
-        unsafe fn setup_fbdev(drm: &Device<Self::Driver>, mode_config_info: &ModeConfigInfo) {
-            build_error::build_error("This should never be reachable")
-        }
     }
 }
 
@@ -125,12 +115,6 @@ impl<'a, T: Driver> UnregisteredKmsDevice<'a, T> {
 /// [`PhantomData<Self>`]: PhantomData
 #[vtable]
 pub trait KmsDriver: Driver {
-    /// The fbdev implementation to use for this [`Device`].
-    ///
-    /// Which implementation may be used here depends on the GEM implementation specified in
-    /// [`Driver::Object`]. See [`fbdev`] for more information.
-    type Fbdev: fbdev::FbdevImpl;
-
     /// Return a [`ModeConfigInfo`] structure for this [`device::Device`].
     fn mode_config_info(
         dev: &device::Device,
@@ -238,10 +222,6 @@ impl<T: KmsDriver> private::KmsImpl for T {
 
         Ok(mode_config_info)
     }
-
-    unsafe fn setup_fbdev(drm: &Device<Self::Driver>, mode_config_info: &ModeConfigInfo) {
-        <<T as KmsDriver>::Fbdev as fbdev::private::FbdevImpl>::setup_fbdev(drm, mode_config_info)
-    }
 }
 
 impl<T: KmsDriver> KmsImpl for T {}

rust/kernel/drm/kms/atomic.rs

@@ -373,13 +373,13 @@ impl<T: KmsDriver> AtomicStateComposer<T> {
 /// A token proving that no modesets for a commit have completed.
 ///
 /// This token is proof that no commits have yet completed, and is provided as an argument to
-/// [`Kms::atomic_commit_tail`]. This may be used with
+/// [`KmsDriver::atomic_commit_tail`]. This may be used with
 /// [`AtomicCommitTail::commit_modeset_disables`].
 pub struct ModesetsReadyToken<'a>(PhantomData<&'a ()>);
 
 /// A token proving that modeset disables for a commit have completed.
 ///
-/// This token is proof that an implementor's [`Kms::atomic_commit_tail`] phase has finished
+/// This token is proof that an implementor's [`KmsDriver::atomic_commit_tail`] phase has finished
 /// committing any operations which disable mode objects. It is returned by
 /// [`AtomicCommitTail::commit_modeset_disables`], and can be used with
 /// [`AtomicCommitTail::commit_modeset_enables`] to acquire a [`EnablesCommittedToken`].
@@ -387,7 +387,7 @@ pub struct DisablesCommittedToken<'a>(PhantomData<&'a ()>);
 
 /// A token proving that modeset enables for a commit have completed.
 ///
-/// This token is proof that an implementor's [`Kms::atomic_commit_tail`] phase has finished
+/// This token is proof that an implementor's [`KmsDriver::atomic_commit_tail`] phase has finished
 /// committing any operations which enable mode objects. It is returned by
 /// [`AtomicCommitTail::commit_modeset_enables`].
 pub struct EnablesCommittedToken<'a>(PhantomData<&'a ()>);
@@ -395,20 +395,20 @@ pub struct EnablesCommittedToken<'a>(PhantomData<&'a ()>);
 /// A token proving that no plane updates for a commit have completed.
 ///
 /// This token is proof that no plane updates have yet been completed within an implementor's
-/// [`Kms::atomic_commit_tail`] implementation, and that we are ready to begin updating planes. It
-/// is provided as an argument to [`Kms::atomic_commit_tail`].
+/// [`KmsDriver::atomic_commit_tail`] implementation, and that we are ready to begin updating planes. It
+/// is provided as an argument to [`KmsDriver::atomic_commit_tail`].
 pub struct PlaneUpdatesReadyToken<'a>(PhantomData<&'a ()>);
 
 /// A token proving that all plane updates for a commit have completed.
 ///
-/// This token is proof that all plane updates within an implementor's [`Kms::atomic_commit_tail`]
+/// This token is proof that all plane updates within an implementor's [`KmsDriver::atomic_commit_tail`]
 /// implementation have completed. It is returned by [`AtomicCommitTail::commit_planes`].
 pub struct PlaneUpdatesCommittedToken<'a>(PhantomData<&'a ()>);
 
 /// An [`AtomicState`] interface that allows a driver to control the [`atomic_commit_tail`]
 /// callback.
 ///
-/// This object is provided as an argument to [`Kms::atomic_commit_tail`], and represents an atomic
+/// This object is provided as an argument to [`KmsDriver::atomic_commit_tail`], and represents an atomic
 /// state within the commit tail phase which is still in the process of being committed to hardware.
 /// It may be used to control the order in which the commit process happens.
 ///
@@ -578,7 +578,7 @@ pub(crate) unsafe extern "C" fn commit_tail_callback<T: KmsDriver>(
 /// It may be assumed that [`drm_atomic_helper_commit_hw_done`] has been called as long as this type
 /// exists.
 ///
-/// [`atomic_commit_tail`]: Kms::atomic_commit_tail
+/// [`atomic_commit_tail`]: KmsDriver::atomic_commit_tail
 /// [`drm_atomic_helper_commit_hw_done`]: srctree/include/drm/drm_atomic_helper.h
 pub struct CommittedAtomicState<'a, T: KmsDriver>(&'a AtomicState<T>);
 

rust/kernel/drm/kms/connector.rs

@@ -200,7 +200,7 @@ impl<T: DriverConnector> Connector<T> {
     /// TODO: Add a way to handle creating connectors after device registration. Also, that's why we
     /// don't ask for a UnregisteredKms device here.
     ///
-    /// [`Kms::create_objects`]: kernel::drm::kms::Kms::create_objects
+    /// [`KmsDriver::create_objects`]: kernel::drm::kms::KmsDriver::create_objects
     pub fn new(
         dev: &Device<T::Driver>,
         type_: u32,

rust/kernel/drm/kms/crtc.rs

@@ -276,10 +276,10 @@ unsafe impl<T: DriverCrtc> StaticModeObject for Crtc<T> { }
 impl<T: DriverCrtc> Crtc<T> {
     /// Construct a new [`Crtc`].
     ///
-    /// A driver may use this from their [`Kms::create_objects`] callback in order to construct new
-    /// [`Crtc`] objects.
+    /// A driver may use this from their [`KmsDriver::create_objects`] callback in order to
+    /// construct new [`Crtc`] objects.
     ///
-    /// [`Kms::create_objects`]: kernel::drm::kms::Kms::create_objects
+    /// [`KmsDriver::create_objects`]: kernel::drm::kms::KmsDriver::create_objects
     pub fn new<'a, 'b: 'a, P, C>(
         dev: &'a UnregisteredKmsDevice<'a, T::Driver>,
         primary: &'a Plane<P>,

rust/kernel/drm/kms/encoder.rs

@@ -204,10 +204,10 @@ unsafe impl<T: DriverEncoder> AsRawEncoder for Encoder<T> {
 impl<T: DriverEncoder> Encoder<T> {
     /// Construct a new [`Encoder`].
     ///
-    /// A driver may use this from their [`Kms::create_objects`] callback in order to construct new
-    /// [`Encoder`] objects.
+    /// A driver may use this from their [`KmsDriver::create_objects`] callback in order to
+    /// construct new [`Encoder`] objects.
     ///
-    /// [`Kms::create_objects`]: kernel::drm::kms::Kms::create_objects
+    /// [`KmsDriver::create_objects`]: kernel::drm::kms::KmsDriver::create_objects
     pub fn new<'a, 'b: 'a>(
         dev: &'a UnregisteredKmsDevice<'a, T::Driver>,
         type_: u32,

rust/kernel/drm/kms/fbdev.rs

-//! Fbdev helper implementations for rust.
-//!
-//! This module provides the various Fbdev implementations that can be used by Rust KMS drivers.
-use core::marker::*;
-use crate::{private::Sealed, drm::{kms::*, device::Device, gem}};
-use bindings;
-
-#[cfg(CONFIG_DRM_GEM_SHMEM_HELPER = "y")]
-mod shmem;
-
-#[cfg(CONFIG_DRM_GEM_SHMEM_HELPER = "y")]
-pub use shmem::FbdevShmem;
-
-pub(crate) mod private {
-    use super::*;
-
-    pub trait FbdevImpl {
-        /// Setup the fbdev implementation for this KMS driver.
-        fn setup_fbdev<T: Driver>(drm: &Device<T>, mode_config_info: &ModeConfigInfo);
-    }
-}
-
-/// The main trait for a driver's DRM implementation.
-///
-/// Drivers are expected not to implement this directly, and to instead use one of the objects
-/// provided by this module such as [`FbdevDma`] and [`FbdevShmem`].
-pub trait FbdevImpl: private::FbdevImpl {}
-
-/// The fbdev implementation for drivers using the gem DMA helpers.
-///
-/// Drivers which use the gem DMA helpers ([`gem::Object`]) should use this for their [`Kms::Fbdev`]
-/// type.
-pub struct FbdevDma<T: Driver>(PhantomData<T>);
-
-impl<T, G> private::FbdevImpl for FbdevDma<T>
-where
-    T: Driver<Object = gem::Object<G>>,
-    G: gem::DriverObject
-{
-    #[inline]
-    fn setup_fbdev<D: Driver>(drm: &Device<D>, mode_config_info: &ModeConfigInfo) {
-        // SAFETY: Our implementation bounds re proof that this driver is using the gem dma helpers
-        unsafe { bindings::drm_fbdev_dma_setup(drm.as_raw(), mode_config_info.preferred_depth) };
-    }
-}
-
-impl<T, G> FbdevImpl for FbdevDma<T>
-where
-    T: Driver<Object = gem::Object<G>>,
-    G: gem::DriverObject
-{}

rust/kernel/drm/kms/fbdev/shmem.rs

-//! The GEM shmem fbdev implementation for rust.
-//!
-//! This module provides an Fbdev implementation that can be used by Rust KMS drivers using the GEM
-//! shmem helpers provided by [`shmem`].
-
-use core::marker::*;
-use crate::drm::{gem::shmem, kms::*, device::Device};
-use super::{private::FbdevImpl as FbdevImplPrivate, FbdevImpl};
-use bindings;
-
-/// The fbdev implementation for drivers using the gem shmem helpers.
-///
-/// KMS Drivers which use the GEM helpers provided by [`shmem`] should use this for [`Kms::Fbdev`].
-pub struct FbdevShmem<T: Driver>(PhantomData<T>);
-
-impl<T, G> FbdevImplPrivate for FbdevShmem<T>
-where
-    T: Driver<Object = shmem::Object<G>>,
-    G: shmem::DriverObject
-{
-    #[inline]
-    fn setup_fbdev<D: Driver>(drm: &Device<D>, mode_config_info: &ModeConfigInfo) {
-        // SAFETY: Our implementation bounds are proof that this driver is using the gem shmem
-        // helpers
-        unsafe { bindings::drm_fbdev_shmem_setup(drm.as_raw(), mode_config_info.preferred_depth) };
-    }
-}
-
-impl<T, G> FbdevImpl for FbdevShmem<T>
-where
-    T: Driver<Object = shmem::Object<G>>,
-    G: shmem::DriverObject
-{}

rust/kernel/drm/kms/plane.rs

@@ -206,10 +206,10 @@ impl<T: DriverPlane> Deref for Plane<T> {
 impl<T: DriverPlane> Plane<T> {
     /// Construct a new [`Plane`].
     ///
-    /// A driver may use this from their [`Kms::create_objects`] callback in order to construct new
+    /// A driver may use this from their [`KmsDriver::create_objects`] callback in order to construct new
     /// [`Plane`] objects.
     ///
-    /// [`Kms::create_objects`]: kernel::drm::kms::Kms::create_objects
+    /// [`KmsDriver::create_objects`]: kernel::drm::kms::KmsDriver::create_objects
     pub fn new<'a, 'b: 'a, const FMT_COUNT: usize, const MOD_COUNT: usize>(
         dev: &'a UnregisteredKmsDevice<'a, T::Driver>,
         possible_crtcs: u32,