[PATCH v4 8/9] gpu: nova-core: create debugfs root when driver loads

[Timur Tabi <ttabi@nvidia.com>]

Create the 'nova_core' root debugfs entry when the driver loads.
The Dir entry is part of the NovaCoreModule, so when the module
unloads, the NovaCoreModule object is dropped, and that drops the
_debugfs_root, which automatically deletes the debugfs file.

Signed-off-by: Timur Tabi <ttabi@nvidia.com>
---
 drivers/gpu/nova-core/nova_core.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index d0df8db3693d..c9b93ccd6092 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -3,6 +3,7 @@
 //! Nova Core GPU Driver
 
 use kernel::{
+    debugfs::{Dir, Directory},
     error::Error,
     pci,
     prelude::*,
@@ -31,12 +32,17 @@
 struct NovaCoreModule {
     #[pin]
     _driver: kernel::driver::Registration<pci::Adapter<driver::NovaCore>>,
+    _debugfs_root: Dir,
 }
 
 impl InPlaceModule for NovaCoreModule {
     fn init(module: &'static kernel::ThisModule) -> impl PinInit<Self, Error> {
+        // Create the debugfs top-level directory.  Each GPU will create a subdirectory.
+        let debugfs_root = Dir::new(kernel::c_str!("nova_core"));
+
         try_pin_init!(Self {
             _driver <- kernel::driver::Registration::new(MODULE_NAME, module),
+            _debugfs_root: debugfs_root,
         })
     }
 }
-- 
2.52.0