Commit 67d8cf92 authored by Louis Chauvet's avatar Louis Chauvet Committed by Luca Ceresoli
Browse files

drm/vkms: Allow to configure multiple encoders via configfs 



Create a default subgroup at /config/vkms/encoders to allow to create as
many encoders 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/20251016175618.10051-9-jose.exposito89@gmail.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent 95fa7378

Documentation/gpu/vkms.rst

+6 −0
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ And directories are created for each configurable item of the display pipeline:: 
  tree /config/vkms/my-vkms

  ├── crtcs

  ├── enabled

  ├── encoders

  └── planes



To add items to the display pipeline, create one or more directories under the
@@ -98,6 +99,10 @@ CRTCs have 1 configurable attribute: 


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



Next, create one or more encoders::



  sudo mkdir /config/vkms/my-vkms/encoders/encoder0



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
@@ -119,6 +124,7 @@ 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/encoders/*

  sudo rmdir /config/vkms/my-vkms



Testing With IGT

drivers/gpu/drm/vkms/vkms_configfs.c

+87 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ static bool is_configfs_registered; 
 * 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"

 * @encoders_group: Default subgroup of @group at "/config/vkms/encoders"

 * @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
@@ -27,6 +28,7 @@ struct vkms_configfs_device { 
	struct config_group group;

	struct config_group planes_group;

	struct config_group crtcs_group;

	struct config_group encoders_group;



	struct mutex lock;

	struct vkms_config *config;
@@ -63,6 +65,20 @@ struct vkms_configfs_crtc { 
	struct vkms_config_crtc *config;

};



/**

 * struct vkms_configfs_encoder - Configfs representation of a encoder

 *

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

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

 * @dev: The vkms_configfs_device this encoder belongs to

 * @config: Configuration of the VKMS encoder

 */

struct vkms_configfs_encoder {

	struct config_group group;

	struct vkms_configfs_device *dev;

	struct vkms_config_encoder *config;

};



#define device_item_to_vkms_configfs_device(item) \

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

		     group)
@@ -80,6 +96,10 @@ struct vkms_configfs_crtc { 
#define crtc_item_to_vkms_configfs_crtc(item) \

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



#define encoder_item_to_vkms_configfs_encoder(item) \

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

		     group)



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

{

	struct vkms_configfs_crtc *crtc;
@@ -344,6 +364,69 @@ static const struct config_item_type plane_group_type = { 
	.ct_owner	= THIS_MODULE,

};



static void encoder_release(struct config_item *item)

{

	struct vkms_configfs_encoder *encoder;

	struct mutex *lock;



	encoder = encoder_item_to_vkms_configfs_encoder(item);

	lock = &encoder->dev->lock;



	scoped_guard(mutex, lock) {

		vkms_config_destroy_encoder(encoder->dev->config, encoder->config);

		kfree(encoder);

	}

}



static struct configfs_item_operations encoder_item_operations = {

	.release	= &encoder_release,

};



static const struct config_item_type encoder_item_type = {

	.ct_item_ops	= &encoder_item_operations,

	.ct_owner	= THIS_MODULE,

};



static struct config_group *make_encoder_group(struct config_group *group,

					       const char *name)

{

	struct vkms_configfs_device *dev;

	struct vkms_configfs_encoder *encoder;



	dev = child_group_to_vkms_configfs_device(group);



	scoped_guard(mutex, &dev->lock) {

		if (dev->enabled)

			return ERR_PTR(-EBUSY);



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

		if (!encoder)

			return ERR_PTR(-ENOMEM);



		encoder->dev = dev;



		encoder->config = vkms_config_create_encoder(dev->config);

		if (IS_ERR(encoder->config)) {

			kfree(encoder);

			return ERR_CAST(encoder->config);

		}



		config_group_init_type_name(&encoder->group, name,

					    &encoder_item_type);

	}



	return &encoder->group;

}



static struct configfs_group_operations encoders_group_operations = {

	.make_group	= &make_encoder_group,

};



static const struct config_item_type encoder_group_type = {

	.ct_group_ops	= &encoders_group_operations,

	.ct_owner	= THIS_MODULE,

};



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

{

	struct vkms_configfs_device *dev;
@@ -447,6 +530,10 @@ static struct config_group *make_device_group(struct config_group *group, 
				    &crtc_group_type);

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



	config_group_init_type_name(&dev->encoders_group, "encoders",

				    &encoder_group_type);

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



	return &dev->group;

}