drm/debugfs: rework debugfs directory creation v5

Instead of the per minor directories only create a single debugfs
directory for the whole device directly when the device is initialized.

For DRM devices each minor gets a symlink to the per device directory
for now until we can be sure that this isn't useful any more in any way.

Accel devices create only the per device directory and also drops the mid
layer callback to create driver specific files.

v2: cleanup accel component as well
v3: fix typo when debugfs is disabled
v4: call drm_debugfs_dev_fini() during release as well,
    some kerneldoc typos fixed
v5: rebased and one more kerneldoc fix

Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-4-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>

15 files changed, 136 insertions, 58 deletions

diff --git a/drivers/accel/drm_accel.c b/drivers/accel/drm_accel.c
index 01edf2c00b5a..8ba3db2ec5bb 100644
--- a/drivers/accel/drm_accel.c
+++ b/drivers/accel/drm_accel.c
@@ -79,26 +79,32 @@ static const struct drm_info_list accel_debugfs_list[] = {
 #define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
 
 /**
- * accel_debugfs_init() - Initialize debugfs for accel minor
- * @minor: Pointer to the drm_minor instance.
- * @minor_id: The minor's id
+ * accel_debugfs_init() - Initialize debugfs for device
+ * @dev: Pointer to the device instance.
  *
- * This function initializes the drm minor's debugfs members and creates
- * a root directory for the minor in debugfs. It also creates common files
- * for accelerators and calls the driver's debugfs init callback.
+ * This function creates a root directory for the device in debugfs.
  */
-void accel_debugfs_init(struct drm_minor *minor, int minor_id)
+void accel_debugfs_init(struct drm_device *dev)
 {
-	struct drm_device *dev = minor->dev;
-	char name[64];
+	drm_debugfs_dev_init(dev, accel_debugfs_root);
+}
+
+/**
+ * accel_debugfs_register() - Register debugfs for device
+ * @dev: Pointer to the device instance.
+ *
+ * Creates common files for accelerators.
+ */
+void accel_debugfs_register(struct drm_device *dev)
+{
+	struct drm_minor *minor = dev->accel;
 
 	INIT_LIST_HEAD(&minor->debugfs_list);
 	mutex_init(&minor->debugfs_lock);
-	sprintf(name, "%d", minor_id);
-	minor->debugfs_root = debugfs_create_dir(name, accel_debugfs_root);
+	minor->debugfs_root = dev->debugfs_root;
 
 	drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
-				 minor->debugfs_root, minor);
+				 dev->debugfs_root, minor);
 }
 
 /**
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 2c454568a607..affce6a8851f 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1832,9 +1832,9 @@ static const struct drm_debugfs_info drm_atomic_debugfs_list[] = {
 	{"state", drm_state_info, 0},
 };
 
-void drm_atomic_debugfs_init(struct drm_minor *minor)
+void drm_atomic_debugfs_init(struct drm_device *dev)
 {
-	drm_debugfs_add_files(minor->dev, drm_atomic_debugfs_list,
+	drm_debugfs_add_files(dev, drm_atomic_debugfs_list,
 			      ARRAY_SIZE(drm_atomic_debugfs_list));
 }
 #endif
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 39e68e45bb12..30d66bee0ec6 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1384,9 +1384,9 @@ static const struct drm_debugfs_info drm_bridge_debugfs_list[] = {
 	{ "bridge_chains", drm_bridge_chains_info, 0 },
 };
 
-void drm_bridge_debugfs_init(struct drm_minor *minor)
+void drm_bridge_debugfs_init(struct drm_device *dev)
 {
-	drm_debugfs_add_files(minor->dev, drm_bridge_debugfs_list,
+	drm_debugfs_add_files(dev, drm_bridge_debugfs_list,
 			      ARRAY_SIZE(drm_bridge_debugfs_list));
 }
 #endif
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
index 037e36f2049c..2762572f286e 100644
--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -535,9 +535,9 @@ static const struct drm_debugfs_info drm_client_debugfs_list[] = {
 	{ "internal_clients", drm_client_debugfs_internal_clients, 0 },
 };
 
-void drm_client_debugfs_init(struct drm_minor *minor)
+void drm_client_debugfs_init(struct drm_device *dev)
 {
-	drm_debugfs_add_files(minor->dev, drm_client_debugfs_list,
+	drm_debugfs_add_files(dev, drm_client_debugfs_list,
 			      ARRAY_SIZE(drm_client_debugfs_list));
 }
 #endif
diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index 501a10edd0e1..8556c3b3ff88 100644
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -232,7 +232,7 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 /* drm_atomic.c */
 #ifdef CONFIG_DEBUG_FS
 struct drm_minor;
-void drm_atomic_debugfs_init(struct drm_minor *minor);
+void drm_atomic_debugfs_init(struct drm_device *dev);
 #endif
 
 int __drm_atomic_helper_disable_plane(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 8a4c90fd9f02..5ec28c0e12d9 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -266,8 +266,46 @@ void drm_debugfs_create_files(const struct drm_info_list *files, int count,
 }
 EXPORT_SYMBOL(drm_debugfs_create_files);
 
-int drm_debugfs_init(struct drm_minor *minor, int minor_id,
-		     struct dentry *root)
+/**
+ * drm_debugfs_dev_init - create debugfs directory for the device
+ * @dev: the device which we want to create the directory for
+ * @root: the parent directory depending on the device type
+ *
+ * Creates the debugfs directory for the device under the given root directory.
+ */
+void drm_debugfs_dev_init(struct drm_device *dev, struct dentry *root)
+{
+	dev->debugfs_root = debugfs_create_dir(dev->unique, root);
+}
+
+/**
+ * drm_debugfs_dev_fini - cleanup debugfs directory
+ * @dev: the device to cleanup the debugfs stuff
+ *
+ * Remove the debugfs directory, might be called multiple times.
+ */
+void drm_debugfs_dev_fini(struct drm_device *dev)
+{
+	debugfs_remove_recursive(dev->debugfs_root);
+	dev->debugfs_root = NULL;
+}
+
+void drm_debugfs_dev_register(struct drm_device *dev)
+{
+	drm_debugfs_add_files(dev, drm_debugfs_list, DRM_DEBUGFS_ENTRIES);
+
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		drm_framebuffer_debugfs_init(dev);
+		drm_client_debugfs_init(dev);
+	}
+	if (drm_drv_uses_atomic_modeset(dev)) {
+		drm_atomic_debugfs_init(dev);
+		drm_bridge_debugfs_init(dev);
+	}
+}
+
+int drm_debugfs_register(struct drm_minor *minor, int minor_id,
+			 struct dentry *root)
 {
 	struct drm_device *dev = minor->dev;
 	struct drm_debugfs_entry *entry, *tmp;
@@ -276,20 +314,11 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 	INIT_LIST_HEAD(&minor->debugfs_list);
 	mutex_init(&minor->debugfs_lock);
 	sprintf(name, "%d", minor_id);
-	minor->debugfs_root = debugfs_create_dir(name, root);
-
-	drm_debugfs_add_files(minor->dev, drm_debugfs_list, DRM_DEBUGFS_ENTRIES);
+	minor->debugfs_symlink = debugfs_create_symlink(name, root,
+							dev->unique);
 
-	if (drm_drv_uses_atomic_modeset(dev)) {
-		drm_atomic_debugfs_init(minor);
-		drm_bridge_debugfs_init(minor);
-	}
-
-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
-		drm_framebuffer_debugfs_init(minor);
-
-		drm_client_debugfs_init(minor);
-	}
+	/* TODO: Only for compatibility with drivers */
+	minor->debugfs_root = dev->debugfs_root;
 
 	if (dev->driver->debugfs_init && dev->render != minor)
 		dev->driver->debugfs_init(minor);
@@ -356,13 +385,12 @@ static void drm_debugfs_remove_all_files(struct drm_minor *minor)
 
 void drm_debugfs_cleanup(struct drm_minor *minor)
 {
-	if (!minor->debugfs_root)
+	if (!minor->debugfs_symlink)
 		return;
 
 	drm_debugfs_remove_all_files(minor);
-
-	debugfs_remove_recursive(minor->debugfs_root);
-	minor->debugfs_root = NULL;
+	debugfs_remove(minor->debugfs_symlink);
+	minor->debugfs_symlink = NULL;
 }
 
 /**
@@ -547,13 +575,13 @@ static const struct file_operations drm_connector_fops = {
 
 void drm_debugfs_connector_add(struct drm_connector *connector)
 {
-	struct drm_minor *minor = connector->dev->primary;
+	struct drm_device *dev = connector->dev;
 	struct dentry *root;
 
-	if (!minor->debugfs_root)
+	if (!dev->debugfs_root)
 		return;
 
-	root = debugfs_create_dir(connector->name, minor->debugfs_root);
+	root = debugfs_create_dir(connector->name, dev->debugfs_root);
 	connector->debugfs_entry = root;
 
 	/* force */
@@ -588,7 +616,7 @@ void drm_debugfs_connector_remove(struct drm_connector *connector)
 
 void drm_debugfs_crtc_add(struct drm_crtc *crtc)
 {
-	struct drm_minor *minor = crtc->dev->primary;
+	struct drm_device *dev = crtc->dev;
 	struct dentry *root;
 	char *name;
 
@@ -596,7 +624,7 @@ void drm_debugfs_crtc_add(struct drm_crtc *crtc)
 	if (!name)
 		return;
 
-	root = debugfs_create_dir(name, minor->debugfs_root);
+	root = debugfs_create_dir(name, dev->debugfs_root);
 	kfree(name);
 
 	crtc->debugfs_entry = root;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3eda026ffac6..d28f415cd733 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -172,10 +172,9 @@ static int drm_minor_register(struct drm_device *dev, enum drm_minor_type type)
 	if (!minor)
 		return 0;
 
-	if (minor->type == DRM_MINOR_ACCEL) {
-		accel_debugfs_init(minor, minor->index);
-	} else {
-		ret = drm_debugfs_init(minor, minor->index, drm_debugfs_root);
+	if (minor->type != DRM_MINOR_ACCEL) {
+		ret = drm_debugfs_register(minor, minor->index,
+					   drm_debugfs_root);
 		if (ret) {
 			DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
 			goto err_debugfs;
@@ -697,6 +696,11 @@ static int drm_dev_init(struct drm_device *dev,
 		goto err;
 	}
 
+	if (drm_core_check_feature(dev, DRIVER_COMPUTE_ACCEL))
+		accel_debugfs_init(dev);
+	else
+		drm_debugfs_dev_init(dev, drm_debugfs_root);
+
 	return 0;
 
 err:
@@ -786,6 +790,9 @@ static void drm_dev_release(struct kref *ref)
 {
 	struct drm_device *dev = container_of(ref, struct drm_device, ref);
 
+	/* Just in case register/unregister was never called */
+	drm_debugfs_dev_fini(dev);
+
 	if (dev->driver->release)
 		dev->driver->release(dev);
 
@@ -916,6 +923,11 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
 	if (drm_dev_needs_global_mutex(dev))
 		mutex_lock(&drm_global_mutex);
 
+	if (drm_core_check_feature(dev, DRIVER_COMPUTE_ACCEL))
+		accel_debugfs_register(dev);
+	else
+		drm_debugfs_dev_register(dev);
+
 	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
 	if (ret)
 		goto err_minors;
@@ -1001,6 +1013,7 @@ void drm_dev_unregister(struct drm_device *dev)
 	drm_minor_unregister(dev, DRM_MINOR_ACCEL);
 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
+	drm_debugfs_dev_fini(dev);
 }
 EXPORT_SYMBOL(drm_dev_unregister);
 
diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index aff3746dedfb..ba51deb6d042 100644
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -1222,9 +1222,9 @@ static const struct drm_debugfs_info drm_framebuffer_debugfs_list[] = {
 	{ "framebuffer", drm_framebuffer_info, 0 },
 };
 
-void drm_framebuffer_debugfs_init(struct drm_minor *minor)
+void drm_framebuffer_debugfs_init(struct drm_device *dev)
 {
-	drm_debugfs_add_files(minor->dev, drm_framebuffer_debugfs_list,
+	drm_debugfs_add_files(dev, drm_framebuffer_debugfs_list,
 			      ARRAY_SIZE(drm_framebuffer_debugfs_list));
 }
 #endif
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index ba12acd55139..dee75a9cc59e 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -180,8 +180,10 @@ void drm_gem_vunmap(struct drm_gem_object *obj, struct iosys_map *map);
 
 /* drm_debugfs.c drm_debugfs_crc.c */
 #if defined(CONFIG_DEBUG_FS)
-int drm_debugfs_init(struct drm_minor *minor, int minor_id,
-		     struct dentry *root);
+void drm_debugfs_dev_fini(struct drm_device *dev);
+void drm_debugfs_dev_register(struct drm_device *dev);
+int drm_debugfs_register(struct drm_minor *minor, int minor_id,
+			 struct dentry *root);
 void drm_debugfs_cleanup(struct drm_minor *minor);
 void drm_debugfs_late_register(struct drm_device *dev);
 void drm_debugfs_connector_add(struct drm_connector *connector);
@@ -190,8 +192,16 @@ void drm_debugfs_crtc_add(struct drm_crtc *crtc);
 void drm_debugfs_crtc_remove(struct drm_crtc *crtc);
 void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc);
 #else
-static inline int drm_debugfs_init(struct drm_minor *minor, int minor_id,
-				   struct dentry *root)
+static inline void drm_debugfs_dev_fini(struct drm_device *dev)
+{
+}
+
+static inline void drm_debugfs_dev_register(struct drm_device *dev)
+{
+}
+
+static inline int drm_debugfs_register(struct drm_minor *minor, int minor_id,
+				       struct dentry *root)
 {
 	return 0;
 }
@@ -259,4 +269,4 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
 /* drm_framebuffer.c */
 void drm_framebuffer_print_info(struct drm_printer *p, unsigned int indent,
 				const struct drm_framebuffer *fb);
-void drm_framebuffer_debugfs_init(struct drm_minor *minor);
+void drm_framebuffer_debugfs_init(struct drm_device *dev);
diff --git a/include/drm/drm_accel.h b/include/drm/drm_accel.h
index d4955062c77e..f4d3784b1dce 100644
--- a/include/drm/drm_accel.h
+++ b/include/drm/drm_accel.h
@@ -58,7 +58,8 @@ int accel_minor_alloc(void);
 void accel_minor_replace(struct drm_minor *minor, int index);
 void accel_set_device_instance_params(struct device *kdev, int index);
 int accel_open(struct inode *inode, struct file *filp);
-void accel_debugfs_init(struct drm_minor *minor, int minor_id);
+void accel_debugfs_init(struct drm_device *dev);
+void accel_debugfs_register(struct drm_device *dev);
 
 #else
 
@@ -89,7 +90,11 @@ static inline void accel_set_device_instance_params(struct device *kdev, int ind
 {
 }
 
-static inline void accel_debugfs_init(struct drm_minor *minor, int minor_id)
+static inline void accel_debugfs_init(struct drm_device *dev)
+{
+}
+
+static inline void accel_debugfs_register(struct drm_device *dev)
 {
 }
 
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index c339fc85fd07..2dd94224f17e 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -950,6 +950,6 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 }
 #endif
 
-void drm_bridge_debugfs_init(struct drm_minor *minor);
+void drm_bridge_debugfs_init(struct drm_device *dev);
 
 #endif
diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
index c0a14b40c039..d47458ecdac4 100644
--- a/include/drm/drm_client.h
+++ b/include/drm/drm_client.h
@@ -195,6 +195,6 @@ int drm_client_modeset_dpms(struct drm_client_dev *client, int mode);
 	drm_for_each_connector_iter(connector, iter) \
 		if (connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
 
-void drm_client_debugfs_init(struct drm_minor *minor);
+void drm_client_debugfs_init(struct drm_device *dev);
 
 #endif
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 7cf4afae2e79..3cf12b14232d 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -312,6 +312,13 @@ struct drm_device {
 	struct drm_fb_helper *fb_helper;
 
 	/**
+	 * @debugfs_root:
+	 *
+	 * Root directory for debugfs files.
+	 */
+	struct dentry *debugfs_root;
+
+	/**
 	 * @debugfs_mutex:
 	 *
 	 * Protects &debugfs_list access.
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 9813fa759b75..9850fe73b739 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -581,4 +581,12 @@ static inline bool drm_firmware_drivers_only(void)
 	return video_firmware_drivers_only();
 }
 
+#if defined(CONFIG_DEBUG_FS)
+void drm_debugfs_dev_init(struct drm_device *dev, struct dentry *root);
+#else
+static void drm_debugfs_dev_init(struct drm_device *dev, struct dentry *root)
+{
+}
+#endif
+
 #endif
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 010239392adf..12930a08368c 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -79,6 +79,7 @@ struct drm_minor {
 	struct device *kdev;		/* Linux device */
 	struct drm_device *dev;
 
+	struct dentry *debugfs_symlink;
 	struct dentry *debugfs_root;
 
 	struct list_head debugfs_list;