[PATCH 3/8] rust: drm: add driver abstractions
Danilo Krummrich
dakr at kernel.org
Tue Mar 25 23:54:30 UTC 2025
Implement the DRM driver abstractions.
The `Driver` trait provides the interface to the actual driver to fill
in the driver specific data, such as the `DriverInfo`, driver features
and IOCTLs.
Co-developed-by: Asahi Lina <lina at asahilina.net>
Signed-off-by: Asahi Lina <lina at asahilina.net>
Signed-off-by: Danilo Krummrich <dakr at kernel.org>
---
rust/bindings/bindings_helper.h | 1 +
rust/kernel/drm/driver.rs | 143 ++++++++++++++++++++++++++++++++
rust/kernel/drm/mod.rs | 8 ++
3 files changed, 152 insertions(+)
create mode 100644 rust/kernel/drm/driver.rs
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index b25ea9fe1663..a6be6dc80249 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -6,6 +6,7 @@
* Sorted alphabetically.
*/
+#include <drm/drm_drv.h>
#include <drm/drm_ioctl.h>
#include <kunit/test.h>
#include <linux/auxiliary_bus.h>
diff --git a/rust/kernel/drm/driver.rs b/rust/kernel/drm/driver.rs
new file mode 100644
index 000000000000..1ac770482ae0
--- /dev/null
+++ b/rust/kernel/drm/driver.rs
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+//! DRM driver core.
+//!
+//! C header: [`include/linux/drm/drm_drv.h`](srctree/include/linux/drm/drm_drv.h)
+
+use crate::{bindings, drm, str::CStr};
+use macros::vtable;
+
+/// Driver use the GEM memory manager. This should be set for all modern drivers.
+pub const FEAT_GEM: u32 = bindings::drm_driver_feature_DRIVER_GEM;
+/// Driver supports mode setting interfaces (KMS).
+pub const FEAT_MODESET: u32 = bindings::drm_driver_feature_DRIVER_MODESET;
+/// Driver supports dedicated render nodes.
+pub const FEAT_RENDER: u32 = bindings::drm_driver_feature_DRIVER_RENDER;
+/// Driver supports the full atomic modesetting userspace API.
+///
+/// Drivers which only use atomic internally, but do not support the full userspace API (e.g. not
+/// all properties converted to atomic, or multi-plane updates are not guaranteed to be tear-free)
+/// should not set this flag.
+pub const FEAT_ATOMIC: u32 = bindings::drm_driver_feature_DRIVER_ATOMIC;
+/// Driver supports DRM sync objects for explicit synchronization of command submission.
+pub const FEAT_SYNCOBJ: u32 = bindings::drm_driver_feature_DRIVER_SYNCOBJ;
+/// Driver supports the timeline flavor of DRM sync objects for explicit synchronization of command
+/// submission.
+pub const FEAT_SYNCOBJ_TIMELINE: u32 = bindings::drm_driver_feature_DRIVER_SYNCOBJ_TIMELINE;
+/// Driver supports compute acceleration devices. This flag is mutually exclusive with `FEAT_RENDER`
+/// and `FEAT_MODESET`. Devices that support both graphics and compute acceleration should be
+/// handled by two drivers that are connected using auxiliary bus.
+pub const FEAT_COMPUTE_ACCEL: u32 = bindings::drm_driver_feature_DRIVER_COMPUTE_ACCEL;
+/// Driver supports user defined GPU VA bindings for GEM objects.
+pub const FEAT_GEM_GPUVA: u32 = bindings::drm_driver_feature_DRIVER_GEM_GPUVA;
+/// Driver supports and requires cursor hotspot information in the cursor plane (e.g. cursor plane
+/// has to actually track the mouse cursor and the clients are required to set hotspot in order for
+/// the cursor planes to work correctly).
+pub const FEAT_CURSOR_HOTSPOT: u32 = bindings::drm_driver_feature_DRIVER_CURSOR_HOTSPOT;
+
+/// Information data for a DRM Driver.
+pub struct DriverInfo {
+ /// Driver major version.
+ pub major: i32,
+ /// Driver minor version.
+ pub minor: i32,
+ /// Driver patchlevel version.
+ pub patchlevel: i32,
+ /// Driver name.
+ pub name: &'static CStr,
+ /// Driver description.
+ pub desc: &'static CStr,
+ /// Driver date.
+ pub date: &'static CStr,
+}
+
+/// Internal memory management operation set, normally created by memory managers (e.g. GEM).
+///
+/// See `kernel::drm::gem` and `kernel::drm::gem::shmem`.
+pub struct AllocOps {
+ #[expect(unused)]
+ pub(crate) gem_create_object: Option<
+ unsafe extern "C" fn(
+ dev: *mut bindings::drm_device,
+ size: usize,
+ ) -> *mut bindings::drm_gem_object,
+ >,
+ #[expect(unused)]
+ pub(crate) prime_handle_to_fd: Option<
+ unsafe extern "C" fn(
+ dev: *mut bindings::drm_device,
+ file_priv: *mut bindings::drm_file,
+ handle: u32,
+ flags: u32,
+ prime_fd: *mut core::ffi::c_int,
+ ) -> core::ffi::c_int,
+ >,
+ #[expect(unused)]
+ pub(crate) prime_fd_to_handle: Option<
+ unsafe extern "C" fn(
+ dev: *mut bindings::drm_device,
+ file_priv: *mut bindings::drm_file,
+ prime_fd: core::ffi::c_int,
+ handle: *mut u32,
+ ) -> core::ffi::c_int,
+ >,
+ #[expect(unused)]
+ pub(crate) gem_prime_import: Option<
+ unsafe extern "C" fn(
+ dev: *mut bindings::drm_device,
+ dma_buf: *mut bindings::dma_buf,
+ ) -> *mut bindings::drm_gem_object,
+ >,
+ #[expect(unused)]
+ pub(crate) gem_prime_import_sg_table: Option<
+ unsafe extern "C" fn(
+ dev: *mut bindings::drm_device,
+ attach: *mut bindings::dma_buf_attachment,
+ sgt: *mut bindings::sg_table,
+ ) -> *mut bindings::drm_gem_object,
+ >,
+ #[expect(unused)]
+ pub(crate) dumb_create: Option<
+ unsafe extern "C" fn(
+ file_priv: *mut bindings::drm_file,
+ dev: *mut bindings::drm_device,
+ args: *mut bindings::drm_mode_create_dumb,
+ ) -> core::ffi::c_int,
+ >,
+ #[expect(unused)]
+ pub(crate) dumb_map_offset: Option<
+ unsafe extern "C" fn(
+ file_priv: *mut bindings::drm_file,
+ dev: *mut bindings::drm_device,
+ handle: u32,
+ offset: *mut u64,
+ ) -> core::ffi::c_int,
+ >,
+}
+
+/// Trait for memory manager implementations. Implemented internally.
+pub trait AllocImpl: super::private::Sealed {
+ /// The C callback operations for this memory manager.
+ const ALLOC_OPS: AllocOps;
+}
+
+/// The DRM `Driver` trait.
+///
+/// This trait must be implemented by drivers in order to create a `struct drm_device` and `struct
+/// drm_driver` to be registered in the DRM subsystem.
+#[vtable]
+pub trait Driver {
+ /// Context data associated with the DRM driver
+ type Data: Sync + Send;
+
+ /// 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;
+
+ /// Driver metadata
+ const INFO: DriverInfo;
+
+ /// IOCTL list. See `kernel::drm::ioctl::declare_drm_ioctls!{}`.
+ const IOCTLS: &'static [drm::ioctl::DrmIoctlDescriptor];
+}
diff --git a/rust/kernel/drm/mod.rs b/rust/kernel/drm/mod.rs
index 9ec6d7cbcaf3..2e3f9a8a9353 100644
--- a/rust/kernel/drm/mod.rs
+++ b/rust/kernel/drm/mod.rs
@@ -2,4 +2,12 @@
//! DRM subsystem abstractions.
+pub mod driver;
pub mod ioctl;
+
+pub use self::driver::Driver;
+pub use self::driver::DriverInfo;
+
+pub(crate) mod private {
+ pub trait Sealed {}
+}
--
2.49.0
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