[PATCH v3 1/6] drm/debugfs: create device-centered debugfs functions

From: Maíra Canal
Date: Wed Dec 07 2022 - 08:24:42 EST


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@xxxxxxxxx>
Signed-off-by: Wambui Karuga <wambui.karugax@xxxxxxxxx>
Signed-off-by: Maíra Canal <mcanal@xxxxxxxxxx>
---
drivers/gpu/drm/drm_debugfs.c | 70 +++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_drv.c | 3 ++
include/drm/drm_debugfs.h | 41 ++++++++++++++++++++
include/drm/drm_device.h | 15 ++++++++
4 files changed, 129 insertions(+)

diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index ee445f4605ba..988fc07b94b4 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -38,6 +38,7 @@
#include <drm/drm_edid.h>
#include <drm/drm_file.h>
#include <drm/drm_gem.h>
+#include <drm/drm_managed.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"
@@ -151,6 +152,21 @@ static int drm_debugfs_open(struct inode *inode, struct file *file)
return single_open(file, node->info_ent->show, node);
}

+static int drm_debugfs_entry_open(struct inode *inode, struct file *file)
+{
+ struct drm_debugfs_entry *entry = inode->i_private;
+ struct drm_debugfs_info *node = &entry->file;
+
+ return single_open(file, node->show, entry);
+}
+
+static const struct file_operations drm_debugfs_entry_fops = {
+ .owner = THIS_MODULE,
+ .open = drm_debugfs_entry_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};

static const struct file_operations drm_debugfs_fops = {
.owner = THIS_MODULE,
@@ -207,6 +223,7 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
struct dentry *root)
{
struct drm_device *dev = minor->dev;
+ struct drm_debugfs_entry *entry, *tmp;
char name[64];

INIT_LIST_HEAD(&minor->debugfs_list);
@@ -230,6 +247,12 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
if (dev->driver->debugfs_init)
dev->driver->debugfs_init(minor);

+ list_for_each_entry_safe(entry, tmp, &dev->debugfs_list, list) {
+ debugfs_create_file(entry->file.name, S_IFREG | S_IRUGO,
+ minor->debugfs_root, entry, &drm_debugfs_entry_fops);
+ list_del(&entry->list);
+ }
+
return 0;
}

@@ -281,6 +304,53 @@ void drm_debugfs_cleanup(struct drm_minor *minor)
minor->debugfs_root = NULL;
}

+/**
+ * drm_debugfs_add_file - Add a given file to the DRM device debugfs file list
+ * @dev: drm device for the ioctl
+ * @name: debugfs file name
+ * @show: show callback
+ * @data: driver-private data, should not be device-specific
+ *
+ * Add a given file entry to the DRM device debugfs file list to be created on
+ * drm_debugfs_init.
+ */
+void drm_debugfs_add_file(struct drm_device *dev, const char *name,
+ int (*show)(struct seq_file*, void*), void *data)
+{
+ struct drm_debugfs_entry *entry = drmm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
+
+ if (!entry)
+ return;
+
+ entry->file.name = name;
+ entry->file.show = show;
+ entry->file.data = data;
+ entry->dev = dev;
+
+ mutex_lock(&dev->debugfs_mutex);
+ list_add(&entry->list, &dev->debugfs_list);
+ mutex_unlock(&dev->debugfs_mutex);
+}
+EXPORT_SYMBOL(drm_debugfs_add_file);
+
+/**
+ * drm_debugfs_add_files - Add an array of files to the DRM device debugfs file list
+ * @dev: drm device for the ioctl
+ * @files: The array of files to create
+ * @count: The number of files given
+ *
+ * Add a given set of debugfs files represented by an array of
+ * &struct drm_debugfs_info in the DRM device debugfs file list.
+ */
+void drm_debugfs_add_files(struct drm_device *dev, const struct drm_debugfs_info *files, int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++)
+ drm_debugfs_add_file(dev, files[i].name, files[i].show, files[i].data);
+}
+EXPORT_SYMBOL(drm_debugfs_add_files);
+
static int connector_show(struct seq_file *m, void *data)
{
struct drm_connector *connector = m->private;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 203bf8d6c34c..c287488c776f 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -575,6 +575,7 @@ static void drm_dev_init_release(struct drm_device *dev, void *res)
mutex_destroy(&dev->clientlist_mutex);
mutex_destroy(&dev->filelist_mutex);
mutex_destroy(&dev->struct_mutex);
+ mutex_destroy(&dev->debugfs_mutex);
drm_legacy_destroy_members(dev);
}

@@ -608,12 +609,14 @@ static int drm_dev_init(struct drm_device *dev,
INIT_LIST_HEAD(&dev->filelist_internal);
INIT_LIST_HEAD(&dev->clientlist);
INIT_LIST_HEAD(&dev->vblank_event_list);
+ INIT_LIST_HEAD(&dev->debugfs_list);

spin_lock_init(&dev->event_lock);
mutex_init(&dev->struct_mutex);
mutex_init(&dev->filelist_mutex);
mutex_init(&dev->clientlist_mutex);
mutex_init(&dev->master_mutex);
+ mutex_init(&dev->debugfs_mutex);

ret = drmm_add_action_or_reset(dev, drm_dev_init_release, NULL);
if (ret)
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)
--
2.38.1