Commit 3e4d5b30 authored by Louis Chauvet's avatar Louis Chauvet Committed by Luca Ceresoli
Browse files

drm/vkms: Allow to configure multiple CRTCs via configfs 



Create a default subgroup at /config/vkms/crtcs to allow to create as
many CRTCs 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/20251016175618.10051-6-jose.exposito89@gmail.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent 187bc306

Documentation/gpu/vkms.rst

+6 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ By default, the instance is disabled:: 
And directories are created for each configurable item of the display pipeline::



  tree /config/vkms/my-vkms

  ├── crtcs

  ├── enabled

  └── planes
@@ -89,6 +90,10 @@ Planes have 1 configurable attribute: 
- type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those

  exposed by the "type" property of a plane)



Continue by creating one or more CRTCs::



  sudo mkdir /config/vkms/my-vkms/crtcs/crtc0



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



  echo "1" | sudo tee /config/vkms/my-vkms/enabled
@@ -100,6 +105,7 @@ Finally, you can remove the VKMS instance disabling it:: 
And removing the top level directory and its subdirectories::



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

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

  sudo rmdir /config/vkms/my-vkms



Testing With IGT

drivers/gpu/drm/vkms/vkms_configfs.c

+85 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 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"

 * @crtcs_group: Default subgroup of @group at "/config/vkms/crtcs"

 * @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
@@ -25,6 +26,7 @@ static bool is_configfs_registered; 
struct vkms_configfs_device {

	struct config_group group;

	struct config_group planes_group;

	struct config_group crtcs_group;



	struct mutex lock;

	struct vkms_config *config;
@@ -45,6 +47,20 @@ struct vkms_configfs_plane { 
	struct vkms_config_plane *config;

};



/**

 * struct vkms_configfs_crtc - Configfs representation of a CRTC

 *

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

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

 * @dev: The vkms_configfs_device this CRTC belongs to

 * @config: Configuration of the VKMS CRTC

 */

struct vkms_configfs_crtc {

	struct config_group group;

	struct vkms_configfs_device *dev;

	struct vkms_config_crtc *config;

};



#define device_item_to_vkms_configfs_device(item) \

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

		     group)
@@ -55,6 +71,71 @@ struct vkms_configfs_plane { 
#define plane_item_to_vkms_configfs_plane(item) \

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



#define crtc_item_to_vkms_configfs_crtc(item) \

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



static void crtc_release(struct config_item *item)

{

	struct vkms_configfs_crtc *crtc;

	struct mutex *lock;



	crtc = crtc_item_to_vkms_configfs_crtc(item);

	lock = &crtc->dev->lock;



	scoped_guard(mutex, lock) {

		vkms_config_destroy_crtc(crtc->dev->config, crtc->config);

		kfree(crtc);

	}

}



static struct configfs_item_operations crtc_item_operations = {

	.release	= &crtc_release,

};



static const struct config_item_type crtc_item_type = {

	.ct_item_ops	= &crtc_item_operations,

	.ct_owner	= THIS_MODULE,

};



static struct config_group *make_crtc_group(struct config_group *group,

					    const char *name)

{

	struct vkms_configfs_device *dev;

	struct vkms_configfs_crtc *crtc;



	dev = child_group_to_vkms_configfs_device(group);



	scoped_guard(mutex, &dev->lock) {

		if (dev->enabled)

			return ERR_PTR(-EBUSY);



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

		if (!crtc)

			return ERR_PTR(-ENOMEM);



		crtc->dev = dev;



		crtc->config = vkms_config_create_crtc(dev->config);

		if (IS_ERR(crtc->config)) {

			kfree(crtc);

			return ERR_CAST(crtc->config);

		}



		config_group_init_type_name(&crtc->group, name, &crtc_item_type);

	}



	return &crtc->group;

}



static struct configfs_group_operations crtcs_group_operations = {

	.make_group	= &make_crtc_group,

};



static const struct config_item_type crtc_group_type = {

	.ct_group_ops	= &crtcs_group_operations,

	.ct_owner	= THIS_MODULE,

};



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

{

	struct vkms_configfs_plane *plane;
@@ -262,6 +343,10 @@ static struct config_group *make_device_group(struct config_group *group, 
				    &plane_group_type);

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



	config_group_init_type_name(&dev->crtcs_group, "crtcs",

				    &crtc_group_type);

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



	return &dev->group;

}