diff options
| -rw-r--r-- | rust/kernel/drm/drv.rs | 57 |
1 files changed, 56 insertions, 1 deletions
diff --git a/rust/kernel/drm/drv.rs b/rust/kernel/drm/drv.rs index cd594a32f9e4..ebb79a8c90ee 100644 --- a/rust/kernel/drm/drv.rs +++ b/rust/kernel/drm/drv.rs @@ -4,7 +4,16 @@ //! //! C header: [`include/linux/drm/drm_drv.h`](srctree/include/linux/drm/drm_drv.h) -use crate::{bindings, drm, private::Sealed, str::CStr, types::ForeignOwnable}; +use crate::{ + alloc::flags::*, + bindings, + devres::Devres, + drm, + error::{Error, Result}, + private::Sealed, + str::CStr, + types::{ARef, ForeignOwnable}, +}; use macros::vtable; /// Driver use the GEM memory manager. This should be set for all modern drivers. @@ -139,3 +148,49 @@ pub trait Driver { /// IOCTL list. See `kernel::drm::ioctl::declare_drm_ioctls!{}`. const IOCTLS: &'static [drm::ioctl::DrmIoctlDescriptor]; } + +/// The registration type of a `drm::device::Device`. +/// +/// Once the `Registration` structure is dropped, the device is unregistered. +pub struct Registration<T: Driver>(ARef<drm::device::Device<T>>); + +impl<T: Driver> Registration<T> { + /// Creates a new [`Registration`] and registers it. + pub fn new(drm: ARef<drm::device::Device<T>>, flags: usize) -> Result<Self> { + // SAFETY: Safe by the invariants of `drm::device::Device`. + let ret = unsafe { bindings::drm_dev_register(drm.as_raw(), flags as u64) }; + if ret < 0 { + return Err(Error::from_errno(ret)); + } + + Ok(Self(drm)) + } + + /// Same as [`Registration::new`}, but transfers ownership of the [`Registration`] to `Devres`. + pub fn new_foreign_owned(drm: ARef<drm::device::Device<T>>, flags: usize) -> Result { + let reg = Registration::<T>::new(drm.clone(), flags)?; + + Devres::new_foreign_owned(drm.as_ref(), reg, GFP_KERNEL) + } + + /// Returns a reference to the `Device` instance for this registration. + pub fn device(&self) -> &drm::device::Device<T> { + &self.0 + } +} + +// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between +// threads, hence it's safe to share it. +unsafe impl<T: Driver> Sync for Registration<T> {} + +// SAFETY: Registration with and unregistration from the DRM subsystem can happen from any thread. +unsafe impl<T: Driver> Send for Registration<T> {} + +impl<T: Driver> Drop for Registration<T> { + /// Removes the registration from the kernel if it has completed successfully before. + fn drop(&mut self) { + // SAFETY: Safe by the invariant of `ARef<drm::device::Device<T>>`. The existance of this + // `Registration` also guarantees the this `drm::device::Device` is actually registered. + unsafe { bindings::drm_dev_unregister(self.0.as_raw()) }; + } +} |