[RFC PATCH 3/8] rust: drm: Add Device and Driver abstractions

[Rob Herring]

On Mon, May 20, 2024 at 07:20:50PM +0200, Danilo Krummrich wrote:
> From: Asahi Lina <lina at asahilina.net>
> 
> Add abstractions for DRM drivers and devices. These go together in one
> commit since both are fairly tightly coupled types.
> 
> A few things have been stubbed out, to be implemented as further bits of
> the DRM subsystem are introduced.
> 
> Signed-off-by: Asahi Lina <lina at asahilina.net>
> Co-developed-by: Danilo Krummrich <dakr at redhat.com>
> Signed-off-by: Danilo Krummrich <dakr at redhat.com>
> ---
>  rust/bindings/bindings_helper.h |   2 +
>  rust/kernel/drm/device.rs       |  87 +++++++++
>  rust/kernel/drm/drv.rs          | 318 ++++++++++++++++++++++++++++++++
>  rust/kernel/drm/mod.rs          |   2 +
>  4 files changed, 409 insertions(+)
>  create mode 100644 rust/kernel/drm/device.rs
>  create mode 100644 rust/kernel/drm/drv.rs

[...]

> diff --git a/rust/kernel/drm/drv.rs b/rust/kernel/drm/drv.rs
> new file mode 100644
> index 000000000000..5dd8f3f8df7c
> --- /dev/null
> +++ b/rust/kernel/drm/drv.rs
> @@ -0,0 +1,318 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +
> +//! DRM driver core.
> +//!
> +//! C header: [`include/linux/drm/drm_drv.h`](../../../../include/linux/drm/drm_drv.h)
> +
> +use crate::{
> +    alloc::flags::*,
> +    bindings, device, drm,
> +    error::code::*,
> +    error::{Error, Result},
> +    prelude::*,
> +    private::Sealed,
> +    str::CStr,
> +    types::{ARef, ForeignOwnable},
> +    ThisModule,
> +};
> +use core::{
> +    marker::{PhantomData, PhantomPinned},
> +    pin::Pin,
> +};
> +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;

This is missing an entry for DRIVER_GEM_GPUVA. And some others perhaps. 
I suppose some are legacy which won't be needed any time soon if ever. 
Not sure if you intend for this to be complete, or you are just adding 
what you are using? Only FEAT_GEM is used by nova ATM.

Rob