Re: [PATCH v4 10/16] drm/vkms: Allow to configure multiple connectors via configfs

[Louis Chauvet <louis.chauvet@bootlin.com>]

Le 07/04/2025 à 10:14, José Expósito a écrit :
> From: Louis Chauvet <louis.chauvet@bootlin.com>
> 
> Create a default subgroup at
> /config/vkms/connectors to allow to create as many connectors as
> required.

Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>

> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> Co-developed-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> ---
>   Documentation/gpu/vkms.rst           |  6 ++
>   drivers/gpu/drm/vkms/vkms_configfs.c | 87 ++++++++++++++++++++++++++++
>   2 files changed, 93 insertions(+)
> 
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 650dbfa76f59..744e2355db23 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -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
> +  ├── connectors
>     ├── crtcs
>     ├── enabled
>     ├── encoders
> @@ -103,6 +104,10 @@ Next, create one or more encoders::
>   
>     sudo mkdir /config/vkms/my-vkms/encoders/encoder0
>   
> +Last but not least, create one or more connectors::
> +
> +  sudo mkdir /config/vkms/my-vkms/connectors/connector0
> +
>   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
> @@ -127,6 +132,7 @@ 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/encoders/*
> +  sudo rmdir /config/vkms/my-vkms/connectors/*
>     sudo rmdir /config/vkms/my-vkms
>   
>   Testing With IGT
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 7de601e39d2b..692e1b708012 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -19,6 +19,7 @@ static bool is_configfs_registered;
>    * @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"
> + * @connectors_group: Default subgroup of @group at "/config/vkms/connectors"
>    * @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
> @@ -29,6 +30,7 @@ struct vkms_configfs_device {
>   	struct config_group planes_group;
>   	struct config_group crtcs_group;
>   	struct config_group encoders_group;
> +	struct config_group connectors_group;
>   
>   	struct mutex lock;
>   	struct vkms_config *config;
> @@ -81,6 +83,20 @@ struct vkms_configfs_encoder {
>   	struct vkms_config_encoder *config;
>   };
>   
> +/**
> + * struct vkms_configfs_connector - Configfs representation of a connector
> + *
> + * @group: Top level configuration group that represents a connector.
> + * Initialized when a new directory is created under "/config/vkms/connectors"
> + * @dev: The vkms_configfs_device this connector belongs to
> + * @config: Configuration of the VKMS connector
> + */
> +struct vkms_configfs_connector {
> +	struct config_group group;
> +	struct vkms_configfs_device *dev;
> +	struct vkms_config_connector *config;
> +};
> +
>   #define device_item_to_vkms_configfs_device(item) \
>   	container_of(to_config_group((item)), struct vkms_configfs_device, \
>   		     group)
> @@ -106,6 +122,10 @@ struct vkms_configfs_encoder {
>   	container_of(to_config_group((item)), struct vkms_configfs_encoder, \
>   		     possible_crtcs_group)
>   
> +#define connector_item_to_vkms_configfs_connector(item) \
> +	container_of(to_config_group((item)), struct vkms_configfs_connector, \
> +		     group)
> +
>   static ssize_t crtc_writeback_show(struct config_item *item, char *page)
>   {
>   	struct vkms_configfs_crtc *crtc;
> @@ -485,6 +505,69 @@ static const struct config_item_type encoder_group_type = {
>   	.ct_owner	= THIS_MODULE,
>   };
>   
> +static void connector_release(struct config_item *item)
> +{
> +	struct vkms_configfs_connector *connector;
> +	struct mutex *lock;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +	lock = &connector->dev->lock;
> +
> +	scoped_guard(mutex, lock) {
> +		vkms_config_destroy_connector(connector->config);
> +		kfree(connector);
> +	}
> +}
> +
> +static struct configfs_item_operations connector_item_operations = {
> +	.release	= &connector_release,
> +};
> +
> +static const struct config_item_type connector_item_type = {
> +	.ct_item_ops	= &connector_item_operations,
> +	.ct_owner	= THIS_MODULE,
> +};
> +
> +static struct config_group *make_connector_group(struct config_group *group,
> +						 const char *name)
> +{
> +	struct vkms_configfs_device *dev;
> +	struct vkms_configfs_connector *connector;
> +
> +	dev = child_group_to_vkms_configfs_device(group);
> +
> +	scoped_guard(mutex, &dev->lock) {
> +		if (dev->enabled)
> +			return ERR_PTR(-EBUSY);
> +
> +		connector = kzalloc(sizeof(*connector), GFP_KERNEL);
> +		if (!connector)
> +			return ERR_PTR(-ENOMEM);
> +
> +		connector->dev = dev;
> +
> +		connector->config = vkms_config_create_connector(dev->config);
> +		if (IS_ERR(connector->config)) {
> +			kfree(connector);
> +			return ERR_CAST(connector->config);
> +		}
> +
> +		config_group_init_type_name(&connector->group, name,
> +					    &connector_item_type);
> +	}
> +
> +	return &connector->group;
> +}
> +
> +static struct configfs_group_operations connectors_group_operations = {
> +	.make_group	= &make_connector_group,
> +};
> +
> +static const struct config_item_type connector_group_type = {
> +	.ct_group_ops	= &connectors_group_operations,
> +	.ct_owner	= THIS_MODULE,
> +};
> +
>   static ssize_t device_enabled_show(struct config_item *item, char *page)
>   {
>   	struct vkms_configfs_device *dev;
> @@ -592,6 +675,10 @@ static struct config_group *make_device_group(struct config_group *group,
>   				    &encoder_group_type);
>   	configfs_add_default_group(&dev->encoders_group, &dev->group);
>   
> +	config_group_init_type_name(&dev->connectors_group, "connectors",
> +				    &connector_group_type);
> +	configfs_add_default_group(&dev->connectors_group, &dev->group);
> +
>   	return &dev->group;
>   }
>   

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com