Commit 95fa7378 authored by Louis Chauvet's avatar Louis Chauvet Committed by Luca Ceresoli
Browse files

drm/vkms: Allow to attach planes and CRTCs via configfs 



Create a default subgroup at /config/vkms/planes/plane/possible_crtcs
that will contain symbolic links to the possible CRTCs for the plane.

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/20251016175618.10051-8-jose.exposito89@gmail.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent ee5c2c7d

Documentation/gpu/vkms.rst

+9 −0
Original line number Diff line number Diff line
@@ -98,6 +98,14 @@ CRTCs have 1 configurable attribute: 


- writeback: Enable or disable writeback connector support by writing 1 or 0



To finish the configuration, link the different pipeline items::



  sudo ln -s /config/vkms/my-vkms/crtcs/crtc0 /config/vkms/my-vkms/planes/plane0/possible_crtcs



Since at least one primary plane is required, make sure to set the right type::



  echo "1" | sudo tee /config/vkms/my-vkms/planes/plane0/type



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



  echo "1" | sudo tee /config/vkms/my-vkms/enabled
@@ -108,6 +116,7 @@ Finally, you can remove the VKMS instance disabling it:: 


And removing the top level directory and its subdirectories::



  sudo rm /config/vkms/my-vkms/planes/*/possible_crtcs/*

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

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

  sudo rmdir /config/vkms/my-vkms

drivers/gpu/drm/vkms/vkms_configfs.c

+58 −0
Original line number Diff line number Diff line
@@ -38,11 +38,13 @@ struct vkms_configfs_device { 
 *

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

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

 * @possible_crtcs_group: Default subgroup of @group at "plane/possible_crtcs"

 * @dev: The vkms_configfs_device this plane belongs to

 * @config: Configuration of the VKMS plane

 */

struct vkms_configfs_plane {

	struct config_group group;

	struct config_group possible_crtcs_group;

	struct vkms_configfs_device *dev;

	struct vkms_config_plane *config;

};
@@ -71,6 +73,10 @@ struct vkms_configfs_crtc { 
#define plane_item_to_vkms_configfs_plane(item) \

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



#define plane_possible_crtcs_item_to_vkms_configfs_plane(item) \

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

		     possible_crtcs_group)



#define crtc_item_to_vkms_configfs_crtc(item) \

	container_of(to_config_group((item)), struct vkms_configfs_crtc, group)
@@ -178,6 +184,52 @@ static const struct config_item_type crtc_group_type = { 
	.ct_owner	= THIS_MODULE,

};



static int plane_possible_crtcs_allow_link(struct config_item *src,

					   struct config_item *target)

{

	struct vkms_configfs_plane *plane;

	struct vkms_configfs_crtc *crtc;

	int ret;



	if (target->ci_type != &crtc_item_type)

		return -EINVAL;



	plane = plane_possible_crtcs_item_to_vkms_configfs_plane(src);

	crtc = crtc_item_to_vkms_configfs_crtc(target);



	scoped_guard(mutex, &plane->dev->lock) {

		if (plane->dev->enabled)

			return -EBUSY;



		ret = vkms_config_plane_attach_crtc(plane->config, crtc->config);

	}



	return ret;

}



static void plane_possible_crtcs_drop_link(struct config_item *src,

					   struct config_item *target)

{

	struct vkms_configfs_plane *plane;

	struct vkms_configfs_crtc *crtc;



	plane = plane_possible_crtcs_item_to_vkms_configfs_plane(src);

	crtc = crtc_item_to_vkms_configfs_crtc(target);



	scoped_guard(mutex, &plane->dev->lock)

		vkms_config_plane_detach_crtc(plane->config, crtc->config);

}



static struct configfs_item_operations plane_possible_crtcs_item_operations = {

	.allow_link	= plane_possible_crtcs_allow_link,

	.drop_link	= plane_possible_crtcs_drop_link,

};



static const struct config_item_type plane_possible_crtcs_group_type = {

	.ct_item_ops	= &plane_possible_crtcs_item_operations,

	.ct_owner	= THIS_MODULE,

};



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

{

	struct vkms_configfs_plane *plane;
@@ -272,6 +324,12 @@ static struct config_group *make_plane_group(struct config_group *group, 
		}



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



		config_group_init_type_name(&plane->possible_crtcs_group,

					    "possible_crtcs",

					    &plane_possible_crtcs_group_type);

		configfs_add_default_group(&plane->possible_crtcs_group,

					   &plane->group);

	}



	return &plane->group;