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

kernel/drm/
driver.rs
