// SPDX-License-Identifier: GPL-2.0 OR MIT //! DRM driver core.//!//! C header: [`include/drm/drm_drv.h`](srctree/include/drm/drm_drv.h) use crate::{    bindings,    device,    drm,    error::to_result,    prelude::*,    sync::aref::ARef, //};use core::ptr::NonNull; /// Driver use the GEM memory manager. This should be set for all modern drivers.pub(crate) const FEAT_GEM: u32 = bindings::drm_driver_feature_DRIVER_GEM;/// Driver supports render nodes, i.e.: /dev/dri/renderDXX devices.pub(crate) const FEAT_RENDER: u32 = bindings::drm_driver_feature_DRIVER_RENDER; /// 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,} /// Internal memory management operation set, normally created by memory managers (e.g. GEM).pub struct AllocOps {    pub(crate) gem_create_object: Option<        unsafe extern "C" fn(            dev: *mut bindings::drm_device,            size: usize,        ) -> *mut bindings::drm_gem_object,    >,    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,    >,    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,    >,    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,    >,    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,    >,    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,    >,    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 + drm::gem::IntoGEMObject {    /// The [`Driver`] implementation for this [`AllocImpl`].    type Driver: drm::Driver;     /// 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;     /// Data owned by the [`Registration`] and accessible within a    /// [`RegistrationGuard`](drm::RegistrationGuard) critical section via    /// [`Device::registration_data_with()`](drm::Device::registration_data_with).    ///    /// The lifetime parameter is tied to the [`Registration`] scope, which is enclosed in the    /// parent bus device binding scope but may be shorter.    type RegistrationData<'a>: Send + Sync + 'a;     /// The type used to manage memory for this driver.    type Object: AllocImpl;     /// The type used to represent a DRM File (client)    type File: drm::file::DriverFile;     /// The bus device type of the parent device that the DRM device is associated with.    type ParentDevice<Ctx: device::DeviceContext>: device::AsBusDevice<Ctx>;     /// Driver metadata    const INFO: DriverInfo;     /// IOCTL list. See `kernel::drm::ioctl::declare_drm_ioctls!{}`.    const IOCTLS: &'static [drm::ioctl::DrmIoctlDescriptor];     /// Sets the `DRIVER_RENDER` feature for this driver.    ///    /// When enabled, the driver exposes `/dev/dri/renderDXX` render nodes to    /// userspace. The render node is an alternate low-privilege way to access    /// the driver, which is enforced on a per-ioctl level. Userspace processes    /// that open the render node can only invoke ioctls explicitly listed as    /// usable from the render node (i.e. marked DRM_RENDER_ALLOW), whereas    /// userspace processes using the master node can invoke any ioctl.    const FEAT_RENDER: bool = false;} /// The registration type of a `drm::Device`.////// Once the `Registration` structure is dropped, the device is unregistered.pub struct Registration<'a, T: Driver> {    drm: ARef<drm::Device<T>>,    _reg_data: Pin<KBox<T::RegistrationData<'a>>>,} impl<'a, T: Driver> Registration<'a, T> {    /// Register a new [`UnregisteredDevice`](drm::UnregisteredDevice) with userspace.    ///    /// # Safety    ///    /// The caller must not `mem::forget()` the returned [`Registration`] or otherwise prevent its    /// [`Drop`] implementation from running, since the registration data may contain borrowed    /// references that become invalid after `'a` ends.    pub unsafe fn new<E>(        dev: &'a device::Device<device::Bound>,        drm: drm::UnregisteredDevice<T>,        reg_data: impl PinInit<T::RegistrationData<'a>, E>,        flags: usize,    ) -> Result<Self>    where        Error: From<E>,    {        let parent = drm.as_ref();        if parent.as_ref().as_raw() != dev.as_raw() {            return Err(EINVAL);        }         let reg_data: Pin<KBox<T::RegistrationData<'a>>> = KBox::pin_init(reg_data, GFP_KERNEL)?;         // Store the registration data pointer in the device before registration, so that it is        // visible once ioctls can be called.        let ptr: NonNull<T::RegistrationData<'static>> =            NonNull::from(Pin::get_ref(reg_data.as_ref())).cast();         // SAFETY: No concurrent access; the device is not yet registered.        unsafe { *drm.registration_data.get() = ptr };         // SAFETY: `drm` is a valid, initialized but not yet registered DRM device.        let ret = unsafe { bindings::drm_dev_register(drm.as_raw(), flags) };        if let Err(e) = to_result(ret) {            // SAFETY: `drm_dev_register()` synchronizes SRCU on failure, so no concurrent            // access to `registration_data` is possible at this point.            unsafe { *drm.registration_data.get() = NonNull::dangling() };            return Err(e);        }         Ok(Self {            drm: (&*drm).into(),            _reg_data: reg_data,        })    }     /// Returns a reference to the `Device` instance for this registration.    pub fn device(&self) -> &drm::Device<T> {        &self.drm    }} // 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> {    fn drop(&mut self) {        // Use `drm_dev_unplug` rather than `drm_dev_unregister` to ensure that existing        // `drm_dev_enter()` critical sections complete before unregistration proceeds. This        // is required for the safety of `RegistrationGuard`, which relies on the SRCU barrier in        // `drm_dev_unplug()` to guarantee that the parent device is still bound within the        // critical section.        //        // SAFETY: Safe by the invariant of `ARef<drm::Device<T>>`. The existence of this        // `Registration` also guarantees that this `drm::Device` is actually registered.        unsafe { bindings::drm_dev_unplug(self.drm.as_raw()) };        // After drm_dev_unplug(), the SRCU barrier guarantees that all RegistrationGuard critical        // sections have completed, so no one holds a reference to reg_data anymore.        // reg_data is dropped here automatically.    }}