Commit 2f1734ba authored by Louis Chauvet's avatar Louis Chauvet Committed by Luca Ceresoli
Browse files

drm/vkms: Allow to configure multiple planes via configfs 



Create a default subgroup at /config/vkms/planes to allow to create as
many planes as required.

Tested-by: default avatarMark Yacoub <markyacoub@google.com>
Reviewed-by: default avatarLouis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
Reviewed-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: default avatarLouis Chauvet <louis.chauvet@bootlin.com>
Co-developed-by: default avatarJosé Expósito <jose.exposito89@gmail.com>
Signed-off-by: default avatarJosé Expósito <jose.exposito89@gmail.com>
Link: https://lore.kernel.org/r/20251016175618.10051-4-jose.exposito89@gmail.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent 13fc9b97

Documentation/gpu/vkms.rst

+15 −1
Original line number Diff line number Diff line
@@ -71,6 +71,19 @@ By default, the instance is disabled:: 
  cat /config/vkms/my-vkms/enabled

  0



And directories are created for each configurable item of the display pipeline::



  tree /config/vkms/my-vkms

  ├── enabled

  └── planes



To add items to the display pipeline, create one or more directories under the

available paths.



Start by creating one or more planes::



  sudo mkdir /config/vkms/my-vkms/planes/plane0



Once you are done configuring the VKMS instance, enable it::



  echo "1" | sudo tee /config/vkms/my-vkms/enabled
@@ -79,8 +92,9 @@ Finally, you can remove the VKMS instance disabling it:: 


  echo "0" | sudo tee /config/vkms/my-vkms/enabled



And removing the top level directory::

And removing the top level directory and its subdirectories::



  sudo rmdir /config/vkms/my-vkms/planes/*

  sudo rmdir /config/vkms/my-vkms



Testing With IGT

drivers/gpu/drm/vkms/vkms_configfs.c

+88 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ static bool is_configfs_registered; 
 *

 * @group: Top level configuration group that represents a VKMS device.

 * Initialized when a new directory is created under "/config/vkms/"

 * @planes_group: Default subgroup of @group at "/config/vkms/planes"

 * @lock: Lock used to project concurrent access to the configuration attributes

 * @config: Protected by @lock. Configuration of the VKMS device

 * @enabled: Protected by @lock. The device is created or destroyed when this
@@ -23,16 +24,99 @@ static bool is_configfs_registered; 
 */

struct vkms_configfs_device {

	struct config_group group;

	struct config_group planes_group;



	struct mutex lock;

	struct vkms_config *config;

	bool enabled;

};



/**

 * struct vkms_configfs_plane - Configfs representation of a plane

 *

 * @group: Top level configuration group that represents a plane.

 * Initialized when a new directory is created under "/config/vkms/planes"

 * @dev: The vkms_configfs_device this plane belongs to

 * @config: Configuration of the VKMS plane

 */

struct vkms_configfs_plane {

	struct config_group group;

	struct vkms_configfs_device *dev;

	struct vkms_config_plane *config;

};



#define device_item_to_vkms_configfs_device(item) \

	container_of(to_config_group((item)), struct vkms_configfs_device, \

		     group)



#define child_group_to_vkms_configfs_device(group) \

	device_item_to_vkms_configfs_device((&(group)->cg_item)->ci_parent)



#define plane_item_to_vkms_configfs_plane(item) \

	container_of(to_config_group((item)), struct vkms_configfs_plane, group)



static void plane_release(struct config_item *item)

{

	struct vkms_configfs_plane *plane;

	struct mutex *lock;



	plane = plane_item_to_vkms_configfs_plane(item);

	lock = &plane->dev->lock;



	scoped_guard(mutex, lock) {

		vkms_config_destroy_plane(plane->config);

		kfree(plane);

	}

}



static struct configfs_item_operations plane_item_operations = {

	.release	= &plane_release,

};



static const struct config_item_type plane_item_type = {

	.ct_item_ops	= &plane_item_operations,

	.ct_owner	= THIS_MODULE,

};



static struct config_group *make_plane_group(struct config_group *group,

					     const char *name)

{

	struct vkms_configfs_device *dev;

	struct vkms_configfs_plane *plane;



	dev = child_group_to_vkms_configfs_device(group);



	scoped_guard(mutex, &dev->lock) {

		if (dev->enabled)

			return ERR_PTR(-EBUSY);



		plane = kzalloc(sizeof(*plane), GFP_KERNEL);

		if (!plane)

			return ERR_PTR(-ENOMEM);



		plane->dev = dev;



		plane->config = vkms_config_create_plane(dev->config);

		if (IS_ERR(plane->config)) {

			kfree(plane);

			return ERR_CAST(plane->config);

		}



		config_group_init_type_name(&plane->group, name, &plane_item_type);

	}



	return &plane->group;

}



static struct configfs_group_operations planes_group_operations = {

	.make_group	= &make_plane_group,

};



static const struct config_item_type plane_group_type = {

	.ct_group_ops	= &planes_group_operations,

	.ct_owner	= THIS_MODULE,

};



static ssize_t device_enabled_show(struct config_item *item, char *page)

{

	struct vkms_configfs_device *dev;
@@ -128,6 +212,10 @@ static struct config_group *make_device_group(struct config_group *group, 
	config_group_init_type_name(&dev->group, name, &device_item_type);

	mutex_init(&dev->lock);



	config_group_init_type_name(&dev->planes_group, "planes",

				    &plane_group_type);

	configfs_add_default_group(&dev->planes_group, &dev->group);



	return &dev->group;

}