@@ -3,6 +3,7 @@
//! KMS driver abstractions for rust.
pub mod connector;
+pub mod crtc;
pub mod fbdev;
pub mod plane;
new file mode 100644
@@ -0,0 +1,501 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+//! KMS driver abstractions for rust.
+
+use super::{
+ plane::*,
+ ModeObject,
+ StaticModeObject,
+ KmsDriver,
+ UnregisteredKmsDevice
+};
+use crate::{
+ bindings,
+ drm::device::Device,
+ device,
+ prelude::*,
+ private::Sealed,
+ error::from_result,
+ types::Opaque,
+ init::Zeroable,
+ sync::Arc,
+ error::to_result,
+};
+use core::{
+ cell::{Cell, UnsafeCell},
+ marker::*,
+ ptr::{NonNull, null, null_mut, addr_of_mut, self},
+ ops::{Deref, DerefMut},
+ mem,
+};
+use macros::vtable;
+
+/// The main trait for implementing the [`struct drm_crtc`] API for [`Crtc`].
+///
+/// Any KMS driver should have at least one implementation of this type, which allows them to create
+/// [`Crtc`] objects. Additionally, a driver may store driver-private data within the type that
+/// implements [`DriverCrtc`] - and it will be made available when using a fully typed [`Crtc`]
+/// object.
+///
+/// # Invariants
+///
+/// - Any C FFI callbacks generated using this trait are guaranteed that passed-in
+/// [`struct drm_crtc`] pointers are contained within a [`Crtc<Self>`].
+/// - Any C FFI callbacks generated using this trait are guaranteed that passed-in
+/// [`struct drm_crtc_state`] pointers are contained within a [`CrtcState<Self::State>`].
+///
+/// [`struct drm_crtc`]: srctree/include/drm/drm_crtc.h
+/// [`struct drm_crtc_state`]: srctree/include/drm/drm_crtc.h
+#[vtable]
+pub trait DriverCrtc: Send + Sync + Sized {
+ /// The generated C vtable for this [`DriverCrtc`] implementation.
+ #[unique]
+ const OPS: &'static DriverCrtcOps = &DriverCrtcOps {
+ funcs: bindings::drm_crtc_funcs {
+ atomic_destroy_state: Some(atomic_destroy_state_callback::<Self::State>),
+ atomic_duplicate_state: Some(atomic_duplicate_state_callback::<Self::State>),
+ atomic_get_property: None,
+ atomic_print_state: None,
+ atomic_set_property: None,
+ cursor_move: None,
+ cursor_set2: None,
+ cursor_set: None,
+ destroy: Some(crtc_destroy_callback::<Self>),
+ disable_vblank: None,
+ early_unregister: None,
+ enable_vblank: None,
+ gamma_set: None, // TODO
+ get_crc_sources: None,
+ get_vblank_counter: None,
+ get_vblank_timestamp: None,
+ late_register: None,
+ page_flip: Some(bindings::drm_atomic_helper_page_flip),
+ page_flip_target: None,
+ reset: Some(crtc_reset_callback::<Self::State>),
+ set_config: Some(bindings::drm_atomic_helper_set_config),
+ set_crc_source: None,
+ set_property: None,
+ verify_crc_source: None,
+ },
+
+ helper_funcs: bindings::drm_crtc_helper_funcs {
+ atomic_disable: None,
+ atomic_enable: None,
+ atomic_check: None,
+ dpms: None,
+ commit: None,
+ prepare: None,
+ disable: None,
+ mode_set: None,
+ mode_valid: None,
+ mode_fixup: None,
+ atomic_begin: None,
+ atomic_flush: None,
+ mode_set_nofb: None,
+ mode_set_base: None,
+ mode_set_base_atomic: None,
+ get_scanout_position: None,
+ },
+ };
+
+ /// The type to pass to the `args` field of [`Crtc::new`].
+ ///
+ /// This type will be made available in in the `args` argument of [`Self::new`]. Drivers which
+ /// don't need this can simply pass [`()`] here.
+ type Args;
+
+ /// The parent [`KmsDriver`] implementation.
+ type Driver: KmsDriver;
+
+ /// The [`DriverCrtcState`] implementation for this [`DriverCrtc`].
+ ///
+ /// See [`DriverCrtcState`] for more info.
+ type State: DriverCrtcState;
+
+ /// The constructor for creating a [`Crtc`] using this [`DriverCrtc`] implementation.
+ ///
+ /// Drivers may use this to instantiate their [`DriverCrtc`] object.
+ fn new(device: &Device<Self::Driver>, args: &Self::Args) -> impl PinInit<Self, Error>;
+}
+
+/// The generated C vtable for a [`DriverCrtc`].
+///
+/// This type is created internally by DRM.
+pub struct DriverCrtcOps {
+ funcs: bindings::drm_crtc_funcs,
+ helper_funcs: bindings::drm_crtc_helper_funcs,
+}
+
+/// The main interface for a [`struct drm_crtc`].
+///
+/// This type is the main interface for dealing with DRM CRTCs. In addition, it also allows
+/// immutable access to whatever private data is contained within an implementor's [`DriverCrtc`]
+/// type.
+///
+/// # Invariants
+///
+/// - `crtc` and `inner` are initialized for as long as this object is made available to users.
+/// - The data layout of this structure begins with [`struct drm_crtc`].
+/// - The atomic state for this type can always be assumed to be of type [`CrtcState<T::State>`].
+///
+/// [`struct drm_crtc`]: srctree/include/drm/drm_crtc.h
+#[repr(C)]
+#[pin_data]
+pub struct Crtc<T: DriverCrtc> {
+ // The FFI drm_crtc object
+ crtc: Opaque<bindings::drm_crtc>,
+ /// The driver's private inner data
+ #[pin]
+ inner: T,
+ #[pin]
+ _p: PhantomPinned,
+}
+
+// SAFETY: DRM expects this struct to be zero-initialized
+unsafe impl Zeroable for bindings::drm_crtc { }
+
+impl<T: DriverCrtc> Sealed for Crtc<T> {}
+
+// SAFETY: Our CRTC interfaces are guaranteed to be thread-safe
+unsafe impl<T: DriverCrtc> Send for Crtc<T> { }
+
+// SAFETY: Our CRTC interfaces are guaranteed to be thread-safe
+unsafe impl<T: DriverCrtc> Sync for Crtc<T> { }
+
+impl<T: DriverCrtc> Deref for Crtc<T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ &self.inner
+ }
+}
+
+impl<T: DriverCrtc> ModeObject for Crtc<T> {
+ type Driver = T::Driver;
+
+ fn drm_dev(&self) -> &Device<Self::Driver> {
+ // SAFETY: DRM connectors exist for as long as the device does, so this pointer is always
+ // valid
+ unsafe { Device::borrow((*self.as_raw()).dev) }
+ }
+
+ fn raw_mode_obj(&self) -> *mut bindings::drm_mode_object {
+ // SAFETY: We don't expose Crtc<T> to users before it's initialized, so `base` is always
+ // initialized
+ unsafe { addr_of_mut!((*self.as_raw()).base) }
+ }
+}
+
+// SAFETY: CRTCs are non-refcounted modesetting objects
+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.
+ ///
+ /// [`Kms::create_objects`]: kernel::drm::kms::Kms::create_objects
+ pub fn new<'a, 'b: 'a, P, C>(
+ dev: &'a UnregisteredKmsDevice<'a, T::Driver>,
+ primary: &'a Plane<P>,
+ cursor: Option<&'a Plane<C>>,
+ name: Option<&CStr>,
+ args: T::Args,
+ ) -> Result<&'b Self>
+ where
+ P: DriverPlane<Driver = T::Driver>,
+ C: DriverPlane<Driver = T::Driver>
+ {
+ let this = Box::try_pin_init(
+ try_pin_init!(Self {
+ crtc: Opaque::new(bindings::drm_crtc {
+ helper_private: &T::OPS.helper_funcs,
+ ..Default::default()
+ }),
+ inner <- T::new(dev, &args),
+ _p: PhantomPinned,
+ }),
+ GFP_KERNEL
+ )?;
+
+ to_result(unsafe {
+ bindings::drm_crtc_init_with_planes(
+ dev.as_raw(),
+ this.as_raw(),
+ primary.as_raw(),
+ cursor.map_or(null_mut(), |c| c.as_raw()),
+ &T::OPS.funcs,
+ name.map_or(null(), |n| n.as_char_ptr())
+ )
+ })?;
+
+ // Convert the box into a raw pointer, we'll re-assemble it in crtc_destroy_callback()
+ // SAFETY: We don't move anything
+ Ok(unsafe { &*Box::into_raw(Pin::into_inner_unchecked(this)) })
+ }
+}
+
+/// A trait implemented by any type that acts as a [`struct drm_crtc`] interface.
+///
+/// This is implemented internally by DRM.
+///
+/// [`struct drm_crtc`]: srctree/include/drm/drm_crtc.h
+pub trait AsRawCrtc: StaticModeObject {
+ /// The type that should be returned for a CRTC state acquired using this CRTC interface
+ type State: FromRawCrtcState;
+
+ /// Return a raw pointer to the `bindings::drm_crtc` for this object
+ fn as_raw(&self) -> *mut bindings::drm_crtc;
+
+ /// Convert a raw `bindings::drm_crtc` pointer into an object of this type.
+ ///
+ /// SAFETY: Callers promise that `ptr` points to a valid instance of this type
+ unsafe fn from_raw<'a>(ptr: *mut bindings::drm_crtc) -> &'a Self;
+}
+
+impl<T: DriverCrtc> AsRawCrtc for Crtc<T> {
+ type State = CrtcState<T::State>;
+
+ fn as_raw(&self) -> *mut bindings::drm_crtc {
+ self.crtc.get()
+ }
+
+ unsafe fn from_raw<'a>(ptr: *mut bindings::drm_crtc) -> &'a Self {
+ // SAFETY: Our data layout starts with `bindings::drm_crtc`
+ unsafe { &*ptr.cast() }
+ }
+}
+
+unsafe impl Zeroable for bindings::drm_crtc_state { }
+
+impl<T: DriverCrtcState> Sealed for CrtcState<T> {}
+
+/// The main trait for implementing the [`struct drm_crtc_state`] API for a [`Crtc`].
+///
+/// A driver may store driver-private data within the implementor's type, which will be available
+/// when using a full typed [`CrtcState`] object.
+///
+/// # Invariants
+///
+/// - Any C FFI callbacks generated using this trait are guaranteed that passed-in
+/// [`struct drm_crtc`] pointers are contained within a [`Crtc<Self::Crtc>`].
+/// - Any C FFI callbacks generated using this trait are guaranteed that passed-in
+/// [`struct drm_crtc_state`] pointers are contained within a [`CrtcState<Self>`].
+///
+/// [`struct drm_crtc`]: srctree/include/drm_crtc.h
+/// [`struct drm_crtc_state`]: srctree/include/drm_crtc.h
+pub trait DriverCrtcState: Clone + Default + Unpin {
+ /// The parent CRTC driver for this CRTC state
+ type Crtc: DriverCrtc<State = Self> where Self: Sized;
+}
+
+/// The main interface for a [`struct drm_crtc_state`].
+///
+/// This type is the main interface for dealing with the atomic state of DRM crtcs. In addition, it
+/// allows access to whatever private data is contained within an implementor's [`DriverCrtcState`]
+/// type.
+///
+/// # Invariants
+///
+/// - `state` and `inner` initialized for as long as this object is exposed to users.
+/// - The data layout of this structure begins with [`struct drm_crtc_state`].
+/// - The CRTC for this type can always be assumed to be of type [`Crtc<T::Crtc>`].
+///
+/// [`struct drm_crtc_state`]: srctree/include/drm/drm_crtc.h
+#[repr(C)]
+pub struct CrtcState<T: DriverCrtcState> {
+ state: Opaque<bindings::drm_crtc_state>,
+ inner: UnsafeCell<T>,
+}
+
+impl<T: DriverCrtcState> Deref for CrtcState<T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: Our interface ensures that `inner` will not be modified unless only a single
+ // mutable reference exists to `inner`, so this is safe
+ unsafe { &*self.inner.get() }
+ }
+}
+
+impl<T: DriverCrtcState> DerefMut for CrtcState<T> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: Our interfaces ensures that we either have one mutable reference to the state
+ // (this one), or multiple immutable references
+ unsafe { self.inner.get_mut() }
+ }
+}
+
+/// A trait implemented by any type which can produce a reference to a [`struct drm_crtc_state`].
+///
+/// This is implemented internally by DRM.
+///
+/// [`struct drm_crtc_state`]: srctree/include/drm/drm_crtc.h
+pub trait AsRawCrtcState: private::AsRawCrtcState {
+ /// The type that this CRTC state interface returns to represent the parent CRTC
+ type Crtc: AsRawCrtc;
+}
+
+pub(crate) mod private {
+ use super::*;
+
+ #[doc(hidden)]
+ pub trait AsRawCrtcState {
+ /// Return a raw pointer to the DRM CRTC state
+ ///
+ /// Note that CRTC states are the only atomic state in KMS which don't nicely follow rust's
+ /// data aliasing rules already.
+ fn as_raw(&self) -> *mut bindings::drm_crtc_state;
+ }
+}
+
+pub(super) use private::AsRawCrtcState as AsRawCrtcStatePrivate;
+
+/// A trait for providing common methods which can be used on any type that can be used as an atomic
+/// CRTC state.
+pub trait RawCrtcState: AsRawCrtcState {
+ /// Return the CRTC that owns this state.
+ fn crtc(&self) -> &Self::Crtc {
+ // SAFETY:
+ // * This type conversion is guaranteed by type invariance
+ // * Our interface ensures that this access follows rust's data-aliasing rules
+ // * `crtc` is guaranteed to never be NULL and is invariant throughout the lifetime of the
+ // state
+ unsafe { <Self::Crtc as AsRawCrtc>::from_raw((*self.as_raw()).crtc) }
+ }
+}
+impl<T: AsRawCrtcState> RawCrtcState for T {}
+
+/// A trait implemented for any type which can be constructed directly from a
+/// [`struct drm_crtc_state`] pointer.
+///
+/// This is implemented internally by DRM.
+///
+/// [`struct drm_crtc_state`]: srctree/include/drm/drm_crtc.h
+pub trait FromRawCrtcState: AsRawCrtcState {
+ /// Obtain a reference back to this type from a raw DRM crtc state pointer
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure that ptr contains a valid instance of this type.
+ unsafe fn from_raw<'a>(ptr: *const bindings::drm_crtc_state) -> &'a Self;
+}
+
+impl<T: DriverCrtcState> private::AsRawCrtcState for CrtcState<T> {
+ #[inline]
+ fn as_raw(&self) -> *mut bindings::drm_crtc_state {
+ self.state.get()
+ }
+}
+
+impl<T: DriverCrtcState> AsRawCrtcState for CrtcState<T> {
+ type Crtc = Crtc<T::Crtc>;
+}
+
+impl<T: DriverCrtcState> FromRawCrtcState for CrtcState<T> {
+ unsafe fn from_raw<'a>(ptr: *const bindings::drm_crtc_state) -> &'a Self {
+ // SAFETY: Our data layout starts with `bindings::drm_crtc_state`
+ unsafe { &*(ptr.cast()) }
+ }
+}
+
+unsafe extern "C" fn crtc_destroy_callback<T: DriverCrtc>(
+ crtc: *mut bindings::drm_crtc
+) {
+ // SAFETY: DRM guarantees that `crtc` points to a valid initialized `drm_crtc`.
+ unsafe { bindings::drm_crtc_cleanup(crtc) };
+
+ // SAFETY:
+ // - DRM guarantees we are now the only one with access to this [`drm_crtc`].
+ // - This cast is safe via `DriverCrtc`s type invariants.
+ // - We created this as a pinned type originally
+ drop(unsafe { Pin::new_unchecked(Box::from_raw(crtc as *mut Crtc<T>)) });
+}
+
+unsafe extern "C" fn atomic_duplicate_state_callback<T: DriverCrtcState>(
+ crtc: *mut bindings::drm_crtc
+) -> *mut bindings::drm_crtc_state {
+ // SAFETY: DRM guarantees that `crtc` points to a valid initialized `drm_crtc`.
+ let state = unsafe { (*crtc).state };
+ if state.is_null() {
+ return null_mut();
+ }
+
+ // SAFETY: This cast is safe via `DriverCrtcState`s type invariants.
+ let crtc = unsafe { Crtc::<T::Crtc>::from_raw(crtc) };
+
+ // SAFETY: This cast is safe via `DriverCrtcState`s type invariants.
+ let state = unsafe { CrtcState::<T>::from_raw(state) };
+
+ let mut new = Box::try_init(
+ try_init!(CrtcState::<T> {
+ state: Opaque::new(Default::default()),
+ inner: UnsafeCell::new((*state).clone()),
+ }),
+ GFP_KERNEL
+ );
+
+ if let Ok(mut new) = new {
+ let new = Box::into_raw(new).cast();
+
+ // SAFETY: DRM simply copies the data from the previous base DRM state here and does not
+ // move the contents of `ptr`
+ unsafe { bindings::__drm_atomic_helper_crtc_duplicate_state(crtc.as_raw(), new) }
+
+ new
+ } else {
+ null_mut()
+ }
+}
+
+unsafe extern "C" fn atomic_destroy_state_callback<T: DriverCrtcState>(
+ _crtc: *mut bindings::drm_crtc,
+ crtc_state: *mut bindings::drm_crtc_state,
+) {
+ // SAFETY: DRM guarantees that `state` points to a valid instance of `drm_crtc_state`
+ unsafe { bindings::__drm_atomic_helper_crtc_destroy_state(crtc_state) };
+
+ // SAFETY:
+ // * DRM guarantees we are the only one with access to this `drm_crtc_state`
+ // * This cast is safe via our type invariants.
+ // * All data in `CrtcState` is either Unpin, or pinned
+ drop(unsafe { Box::from_raw(crtc_state as *mut CrtcState<T>) });
+}
+
+unsafe extern "C" fn crtc_reset_callback<T: DriverCrtcState>(
+ crtc: *mut bindings::drm_crtc,
+) {
+ // SAFETY: DRM guarantees that `state` points to a valid instance of `drm_crtc_state`
+ let state = unsafe { (*crtc).state };
+ if !state.is_null() {
+ // SAFETY:
+ // * We're guaranteed `crtc` is `Crtc<T>` via type invariants
+ // * We're guaranteed `state` is `CrtcState<T>` via type invariants.
+ unsafe { atomic_destroy_state_callback::<T>(crtc, state) }
+
+ // SAFETY: No special requirements here, DRM expects this to be NULL
+ unsafe { (*crtc).state = null_mut(); }
+ }
+
+ // SAFETY: `crtc` is guaranteed to be of type `Crtc<T::Crtc>` by type invariance
+ let crtc = unsafe { Crtc::<T::Crtc>::from_raw(crtc) };
+
+ // Unfortunately, this is the best we can do at the moment as this FFI callback was mistakenly
+ // presumed to be infallible :(
+ let new = Box::try_init(
+ try_init!(CrtcState::<T> {
+ state: Opaque::new(Default::default()),
+ inner: UnsafeCell::new(Default::default()),
+ }),
+ GFP_KERNEL
+ ).expect("Unfortunately, this API was presumed infallible");
+
+ // SAFETY: DRM takes ownership of the state from here, and will never move it
+ unsafe {
+ bindings::__drm_atomic_helper_crtc_reset(
+ crtc.as_raw(),
+ Box::into_raw(new).cast()
+ )
+ };
+}