kernel/drm/
driver.rs

1// SPDX-License-Identifier: GPL-2.0 OR MIT
2
3//! DRM driver core.
4//!
5//! C header: [`include/drm/drm_drv.h`](srctree/include/drm/drm_drv.h)
6
7use crate::{
8    bindings, device, devres, drm,
9    error::{to_result, Result},
10    prelude::*,
11    sync::aref::ARef,
12};
13use macros::vtable;
14
15/// Driver use the GEM memory manager. This should be set for all modern drivers.
16pub(crate) const FEAT_GEM: u32 = bindings::drm_driver_feature_DRIVER_GEM;
17
18/// Information data for a DRM Driver.
19pub struct DriverInfo {
20    /// Driver major version.
21    pub major: i32,
22    /// Driver minor version.
23    pub minor: i32,
24    /// Driver patchlevel version.
25    pub patchlevel: i32,
26    /// Driver name.
27    pub name: &'static CStr,
28    /// Driver description.
29    pub desc: &'static CStr,
30}
31
32/// Internal memory management operation set, normally created by memory managers (e.g. GEM).
33pub struct AllocOps {
34    pub(crate) gem_create_object: Option<
35        unsafe extern "C" fn(
36            dev: *mut bindings::drm_device,
37            size: usize,
38        ) -> *mut bindings::drm_gem_object,
39    >,
40    pub(crate) prime_handle_to_fd: Option<
41        unsafe extern "C" fn(
42            dev: *mut bindings::drm_device,
43            file_priv: *mut bindings::drm_file,
44            handle: u32,
45            flags: u32,
46            prime_fd: *mut core::ffi::c_int,
47        ) -> core::ffi::c_int,
48    >,
49    pub(crate) prime_fd_to_handle: Option<
50        unsafe extern "C" fn(
51            dev: *mut bindings::drm_device,
52            file_priv: *mut bindings::drm_file,
53            prime_fd: core::ffi::c_int,
54            handle: *mut u32,
55        ) -> core::ffi::c_int,
56    >,
57    pub(crate) gem_prime_import: Option<
58        unsafe extern "C" fn(
59            dev: *mut bindings::drm_device,
60            dma_buf: *mut bindings::dma_buf,
61        ) -> *mut bindings::drm_gem_object,
62    >,
63    pub(crate) gem_prime_import_sg_table: Option<
64        unsafe extern "C" fn(
65            dev: *mut bindings::drm_device,
66            attach: *mut bindings::dma_buf_attachment,
67            sgt: *mut bindings::sg_table,
68        ) -> *mut bindings::drm_gem_object,
69    >,
70    pub(crate) dumb_create: Option<
71        unsafe extern "C" fn(
72            file_priv: *mut bindings::drm_file,
73            dev: *mut bindings::drm_device,
74            args: *mut bindings::drm_mode_create_dumb,
75        ) -> core::ffi::c_int,
76    >,
77    pub(crate) dumb_map_offset: Option<
78        unsafe extern "C" fn(
79            file_priv: *mut bindings::drm_file,
80            dev: *mut bindings::drm_device,
81            handle: u32,
82            offset: *mut u64,
83        ) -> core::ffi::c_int,
84    >,
85}
86
87/// Trait for memory manager implementations. Implemented internally.
88pub trait AllocImpl: super::private::Sealed + drm::gem::IntoGEMObject {
89    /// The [`Driver`] implementation for this [`AllocImpl`].
90    type Driver: drm::Driver;
91
92    /// The C callback operations for this memory manager.
93    const ALLOC_OPS: AllocOps;
94}
95
96/// The DRM `Driver` trait.
97///
98/// This trait must be implemented by drivers in order to create a `struct drm_device` and `struct
99/// drm_driver` to be registered in the DRM subsystem.
100#[vtable]
101pub trait Driver {
102    /// Context data associated with the DRM driver
103    type Data: Sync + Send;
104
105    /// The type used to manage memory for this driver.
106    type Object: AllocImpl;
107
108    /// The type used to represent a DRM File (client)
109    type File: drm::file::DriverFile;
110
111    /// Driver metadata
112    const INFO: DriverInfo;
113
114    /// IOCTL list. See `kernel::drm::ioctl::declare_drm_ioctls!{}`.
115    const IOCTLS: &'static [drm::ioctl::DrmIoctlDescriptor];
116}
117
118/// The registration type of a `drm::Device`.
119///
120/// Once the `Registration` structure is dropped, the device is unregistered.
121pub struct Registration<T: Driver>(ARef<drm::Device<T>>);
122
123impl<T: Driver> Registration<T> {
124    /// Creates a new [`Registration`] and registers it.
125    fn new(drm: &drm::Device<T>, flags: usize) -> Result<Self> {
126        // SAFETY: `drm.as_raw()` is valid by the invariants of `drm::Device`.
127        to_result(unsafe { bindings::drm_dev_register(drm.as_raw(), flags) })?;
128
129        Ok(Self(drm.into()))
130    }
131
132    /// Same as [`Registration::new`}, but transfers ownership of the [`Registration`] to
133    /// [`devres::register`].
134    pub fn new_foreign_owned(
135        drm: &drm::Device<T>,
136        dev: &device::Device<device::Bound>,
137        flags: usize,
138    ) -> Result
139    where
140        T: 'static,
141    {
142        if drm.as_ref().as_raw() != dev.as_raw() {
143            return Err(EINVAL);
144        }
145
146        let reg = Registration::<T>::new(drm, flags)?;
147
148        devres::register(dev, reg, GFP_KERNEL)
149    }
150
151    /// Returns a reference to the `Device` instance for this registration.
152    pub fn device(&self) -> &drm::Device<T> {
153        &self.0
154    }
155}
156
157// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between
158// threads, hence it's safe to share it.
159unsafe impl<T: Driver> Sync for Registration<T> {}
160
161// SAFETY: Registration with and unregistration from the DRM subsystem can happen from any thread.
162unsafe impl<T: Driver> Send for Registration<T> {}
163
164impl<T: Driver> Drop for Registration<T> {
165    fn drop(&mut self) {
166        // SAFETY: Safe by the invariant of `ARef<drm::Device<T>>`. The existence of this
167        // `Registration` also guarantees the this `drm::Device` is actually registered.
168        unsafe { bindings::drm_dev_unregister(self.0.as_raw()) };
169    }
170}
kernel/drm/driver.rs

kernel/drm/
driver.rs
