nova: add initial driver stubHEADnova-next

Add the initial driver stub of Nova, a Rust-based GSP-only driver for
Nvidia GPUs. Nova, in the long term, is intended to serve as the
successor of Nouveau for GSP-firmware-based GPUs. [1]

As a stub driver Nova's focus is to make use of the most basic device /
driver infrastructure required to build a DRM driver on the PCI bus and
serve as demonstration example and justification for this
infrastructure.

In further consequence, the idea is to develop Nova continuously
upstream, using those increments to lift further Rust abstractions and
infrastructure upstream.

Link: https://lore.kernel.org/dri-devel/Zfsj0_tb-0-tNrJy@cassiopeiae/T/#u [1]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 70 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
new file mode 100644
index 000000000000..0cabaee327bb
--- /dev/null
+++ b/drivers/gpu/drm/nova/file.rs
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use crate::driver::{NovaDevice, NovaDriver};
+use crate::gem;
+use kernel::{
+    alloc::flags::*,
+    drm::{self, device::Device as DrmDevice, gem::BaseObject},
+    prelude::*,
+    uapi,
+};
+
+pub(crate) struct File();
+
+/// Convenience type alias for our DRM `File` type
+pub(crate) type DrmFile = drm::file::File<File>;
+
+impl drm::file::DriverFile for File {
+    type Driver = NovaDriver;
+
+    fn open(dev: &DrmDevice<Self::Driver>) -> Result<Pin<KBox<Self>>> {
+        dev_dbg!(dev.as_ref(), "drm::device::Device::open\n");
+
+        Ok(KBox::new(Self(), GFP_KERNEL)?.into())
+    }
+}
+
+impl File {
+    /// IOCTL: get_param: Query GPU / driver metadata.
+    pub(crate) fn get_param(
+        dev: &NovaDevice,
+        getparam: &mut uapi::drm_nova_getparam,
+        _file: &DrmFile,
+    ) -> Result<u32> {
+        let pdev = &dev.data().pdev;
+
+        getparam.value = match getparam.param as u32 {
+            uapi::NOVA_GETPARAM_VRAM_BAR_SIZE => pdev.resource_len(1)?,
+            _ => return Err(EINVAL),
+        };
+
+        Ok(0)
+    }
+
+    /// IOCTL: gem_create: Create a new DRM GEM object.
+    pub(crate) fn gem_create(
+        dev: &NovaDevice,
+        req: &mut uapi::drm_nova_gem_create,
+        file: &DrmFile,
+    ) -> Result<u32> {
+        let obj = gem::object_new(dev, req.size.try_into()?)?;
+
+        let handle = obj.create_handle(file)?;
+        req.handle = handle;
+
+        Ok(0)
+    }
+
+    /// IOCTL: gem_info: Query GEM metadata.
+    pub(crate) fn gem_info(
+        _dev: &NovaDevice,
+        req: &mut uapi::drm_nova_gem_info,
+        file: &DrmFile,
+    ) -> Result<u32> {
+        let bo = gem::lookup_handle(file, req.handle)?;
+
+        req.size = bo.size().try_into()?;
+
+        Ok(0)
+    }
+}