kernel/drm/
driver.rs

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

kernel/drm/
driver.rs
