drm/debugfs: create device-centered debugfs functions

Introduce the ability to track requests for the addition of DRM debugfs
files at any time and have them added all at once during
drm_dev_register().

Drivers can add DRM debugfs files to a device-managed list and, during
drm_dev_register(), all added files will be created at once.

Now, the drivers can use the functions drm_debugfs_add_file() and
drm_debugfs_add_files() to create DRM debugfs files instead of using the
drm_debugfs_create_files() function.

Co-developed-by: Wambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219120621.15086-2-mcanal@igalia.com

2 files changed, 56 insertions, 0 deletions

diff --git a/include/drm/drm_debugfs.h b/include/drm/drm_debugfs.h
index 2188dc83957f..53b7297260a5 100644
--- a/include/drm/drm_debugfs.h
+++ b/include/drm/drm_debugfs.h
@@ -79,12 +79,43 @@ struct drm_info_node {
 	struct dentry *dent;
 };
 
+/**
+ * struct drm_debugfs_info - debugfs info list entry
+ *
+ * This structure represents a debugfs file to be created by the drm
+ * core.
+ */
+struct drm_debugfs_info {
+	const char *name;
+	int (*show)(struct seq_file*, void*);
+	u32 driver_features;
+	void *data;
+};
+
+/**
+ * struct drm_debugfs_entry - Per-device debugfs node structure
+ *
+ * This structure represents a debugfs file, as an instantiation of a &struct
+ * drm_debugfs_info on a &struct drm_device.
+ */
+struct drm_debugfs_entry {
+	struct drm_device *dev;
+	struct drm_debugfs_info file;
+	struct list_head list;
+};
+
 #if defined(CONFIG_DEBUG_FS)
 void drm_debugfs_create_files(const struct drm_info_list *files,
 			      int count, struct dentry *root,
 			      struct drm_minor *minor);
 int drm_debugfs_remove_files(const struct drm_info_list *files,
 			     int count, struct drm_minor *minor);
+
+void drm_debugfs_add_file(struct drm_device *dev, const char *name,
+			  int (*show)(struct seq_file*, void*), void *data);
+
+void drm_debugfs_add_files(struct drm_device *dev,
+			   const struct drm_debugfs_info *files, int count);
 #else
 static inline void drm_debugfs_create_files(const struct drm_info_list *files,
 					    int count, struct dentry *root,
@@ -96,6 +127,16 @@ static inline int drm_debugfs_remove_files(const struct drm_info_list *files,
 {
 	return 0;
 }
+
+static inline void drm_debugfs_add_file(struct drm_device *dev, const char *name,
+					int (*show)(struct seq_file*, void*),
+					void *data)
+{}
+
+static inline void drm_debugfs_add_files(struct drm_device *dev,
+					 const struct drm_debugfs_info *files,
+					 int count)
+{}
 #endif
 
 #endif /* _DRM_DEBUGFS_H_ */
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 9923c7a6885e..fa6af1d57929 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -295,6 +295,21 @@ struct drm_device {
 	 */
 	struct drm_fb_helper *fb_helper;
 
+	/**
+	 * @debugfs_mutex:
+	 *
+	 * Protects &debugfs_list access.
+	 */
+	struct mutex debugfs_mutex;
+
+	/**
+	 * @debugfs_list:
+	 *
+	 * List of debugfs files to be created by the DRM device. The files
+	 * must be added during drm_dev_register().
+	 */
+	struct list_head debugfs_list;
+
 	/* Everything below here is for legacy driver, never use! */
 	/* private: */
 #if IS_ENABLED(CONFIG_DRM_LEGACY)