Message-Id: <20250121-google-config-fs-v3-7-8154a6945142@bootlin.com>
Date: Tue, 21 Jan 2025 15:34:51 +0100
From: Louis Chauvet <louis.chauvet@...tlin.com>
To: Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>, 
 Melissa Wen <melissa.srw@...il.com>, 
 Maíra Canal <mairacanal@...eup.net>, 
 Haneen Mohammed <hamohammed.sa@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Simona Vetter <simona.vetter@...ll.ch>
Cc: jose.exposito89@...il.com, dri-devel@...ts.freedesktop.org, 
 arthurgrillo@...eup.net, linux-kernel@...r.kernel.org, 
 jeremie.dautheribes@...tlin.com, miquel.raynal@...tlin.com, 
 thomas.petazzoni@...tlin.com, seanpaul@...gle.com, nicolejadeyee@...gle.com, 
 Louis Chauvet <louis.chauvet@...tlin.com>
Subject: [PATCH RFC v3 07/14] drm/vkms: Introduce configfs for connectors

To allows the userspace to test many hardware configuration, introduce a
new interface to create and configure connectors.

The connectors are created by creating a directory in the `connectors`
directory.

Connectors and encoders can be linked by creating a symlink in the
possible_encoders directory.

The current interface is:
/config/vkms
        DEVICE_1
        ┣━ enable
        ┣━ planes
        ┃  ┗━ [...]
        ┣━ connectors
        ┃  ┗━ CONNECTOR_1
        ┃     ┗━ possible_encoders
        ┃        ┗━ >> DEVICE_1/encoders/ENCODER_1
        ┗━ encoders
           ┗━ ENCODER_1

Signed-off-by: Louis Chauvet <louis.chauvet@...tlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c   |  13 ++++
 drivers/gpu/drm/vkms/vkms_config.h   |   3 +
 drivers/gpu/drm/vkms/vkms_configfs.c | 138 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.h |  23 ++++++
 4 files changed, 177 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 8ac9cd52cc00f7c317f2514a73c3d2f3908b085b..cb97bf292b72e9faf0050338fe845a254f691987 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -479,6 +479,19 @@ vkms_config_connector_attach_encoder(struct vkms_config_connector *vkms_config_c
 	return ret;
 }
 
+void vkms_config_connector_detach_encoder(struct vkms_config_connector *vkms_config_connector,
+					  struct vkms_config_encoder *vkms_config_encoder)
+{
+	struct vkms_config_encoder *encoder_entry;
+	unsigned long encoder_idx;
+
+	xa_for_each(&vkms_config_connector->possible_encoders, encoder_idx, encoder_entry) {
+		if (encoder_entry == vkms_config_encoder)
+			break;
+	}
+	xa_erase(&vkms_config_connector->possible_encoders, encoder_idx);
+}
+
 bool vkms_config_is_valid(struct vkms_config *config)
 {
 	struct vkms_config_plane *config_plane;
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 2e5d2aa34a4f039c738cb9ac5642f3c75df36ba7..57cdf5fc2df1a62f57b4588c36ad0a99f63bee2a 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -189,6 +189,9 @@ int __must_check vkms_config_encoder_attach_crtc(struct vkms_config_encoder *vkm
 int __must_check
 vkms_config_connector_attach_encoder(struct vkms_config_connector *vkms_config_connector,
 				     struct vkms_config_encoder *vkms_config_encoder);
+void vkms_config_connector_detach_encoder(struct vkms_config_connector *vkms_config_connector,
+					  struct vkms_config_encoder *vkms_config_encoder);
+
 /**
  * vkms_config_delete_plane() - Remove a plane configuration and frees its memory
  *
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 9f41506849552960970aa08b9329b4f88d0aa8e7..8bb3223c810dddb7d713ad4b01cece825f9939f6 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -536,6 +536,7 @@ static struct config_group *encoder_make_group(struct config_group *config_group
 	}
 
 	strscpy(vkms_configfs_encoder->vkms_config_encoder->name, name, strlen(name) + 1);
+
 	config_group_init_type_name(&vkms_configfs_encoder->group, name,
 				    &encoder_item_type);
 
@@ -559,6 +560,139 @@ static const struct config_item_type encoders_item_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
+static int connector_possible_encoders_allow_link(struct config_item *src,
+						  struct config_item *target)
+{
+	struct vkms_config_encoder *vkms_config_encoder;
+	struct vkms_configfs_device *vkms_configfs =
+		connector_possible_encoder_src_item_to_vkms_configfs_device
+		(src);
+
+	mutex_lock(&vkms_configfs->lock);
+
+	if (target->ci_type != &encoder_item_type) {
+		DRM_ERROR("Unable to link non-CRTCs.\n");
+		mutex_unlock(&vkms_configfs->lock);
+		return -EINVAL;
+	}
+
+	vkms_config_encoder = encoder_item_to_vkms_configfs_encoder(target)
+				      ->vkms_config_encoder;
+	struct vkms_config_connector *vkms_config_connector =
+		connector_possible_encoder_src_item_to_vkms_configfs_connector
+		(src)
+			->vkms_config_connector;
+
+	if (vkms_config_connector_attach_encoder(vkms_config_connector,
+						 vkms_config_encoder))
+		return -EINVAL;
+
+	mutex_unlock(&vkms_configfs->lock);
+
+	return 0;
+}
+
+static void connector_possible_encoders_drop_link(struct config_item *src,
+						  struct config_item *target)
+{
+	struct vkms_config_encoder *vkms_config_encoder;
+	struct vkms_configfs_device *vkms_configfs =
+		connector_possible_encoder_src_item_to_vkms_configfs_device(src);
+
+	mutex_lock(&vkms_configfs->lock);
+
+	vkms_config_encoder = encoder_item_to_vkms_configfs_encoder(target)->vkms_config_encoder;
+	struct vkms_config_connector *vkms_config_connector =
+		connector_possible_encoder_src_item_to_vkms_configfs_connector(src)
+			->vkms_config_connector;
+
+	vkms_config_connector_detach_encoder(vkms_config_connector, vkms_config_encoder);
+
+	mutex_unlock(&vkms_configfs->lock);
+}
+
+static struct configfs_item_operations connector_possible_encoders_item_operations = {
+	.allow_link = &connector_possible_encoders_allow_link,
+	.drop_link = &connector_possible_encoders_drop_link,
+};
+
+static struct config_item_type connector_possible_encoders_item_type = {
+	.ct_item_ops = &connector_possible_encoders_item_operations,
+	.ct_owner = THIS_MODULE,
+};
+
+static void connector_release(struct config_item *item)
+{
+	struct vkms_configfs_connector *vkms_configfs_connector =
+		connector_item_to_vkms_configfs_connector(item);
+
+	mutex_lock(&vkms_configfs_connector->vkms_configfs_device->lock);
+	vkms_config_delete_connector(vkms_configfs_connector->vkms_config_connector);
+	mutex_unlock(&vkms_configfs_connector->vkms_configfs_device->lock);
+
+	kfree(vkms_configfs_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 *connector_make_group(struct config_group *config_group,
+						 const char *name)
+{
+	struct vkms_configfs_device *vkms_configfs =
+		connector_item_to_vkms_configfs_device(&config_group->cg_item);
+	struct vkms_configfs_connector *vkms_configfs_connector;
+
+	vkms_configfs_connector = kzalloc(sizeof(*vkms_configfs_connector), GFP_KERNEL);
+
+	if (!vkms_configfs_connector)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&vkms_configfs->lock);
+
+	if (vkms_configfs->enabled) {
+		kfree(vkms_configfs_connector);
+		mutex_unlock(&vkms_configfs->lock);
+		return ERR_PTR(-EINVAL);
+	}
+
+	vkms_configfs_connector->vkms_config_connector =
+		vkms_config_create_connector(vkms_configfs->vkms_config);
+
+	if (!vkms_configfs_connector->vkms_config_connector) {
+		kfree(vkms_configfs_connector);
+		mutex_unlock(&vkms_configfs->lock);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	config_group_init_type_name(&vkms_configfs_connector->group, name, &connector_item_type);
+
+	config_group_init_type_name(&vkms_configfs_connector->possible_encoder_group,
+				    "possible_encoders", &connector_possible_encoders_item_type);
+	configfs_add_default_group(&vkms_configfs_connector->possible_encoder_group,
+				   &vkms_configfs_connector->group);
+	vkms_configfs_connector->vkms_configfs_device = vkms_configfs;
+
+	mutex_unlock(&vkms_configfs->lock);
+
+	return &vkms_configfs_connector->group;
+}
+
+static struct configfs_group_operations connector_group_operations = {
+	.make_group = &connector_make_group,
+};
+
+static const struct config_item_type connectors_item_type = {
+	.ct_group_ops = &connector_group_operations,
+	.ct_owner = THIS_MODULE,
+};
+
 /**
  * configfs_lock_dependencies() - In order to forbid the userspace to delete items when the
  * device is enabled, mark all configfs items as dependent
@@ -705,6 +839,10 @@ static struct config_group *root_make_group(struct config_group *group,
 	config_group_init_type_name(&configfs->encoder_group, "encoders", &encoders_item_type);
 	configfs_add_default_group(&configfs->encoder_group, &configfs->group);
 
+	config_group_init_type_name(&configfs->connector_group, "connectors",
+				    &connectors_item_type);
+	configfs_add_default_group(&configfs->connector_group, &configfs->group);
+
 	return &configfs->group;
 }
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h
index c033810f86ce467f564a14f74165198f12ea044c..5e13941df3382ed30770e79a0432bf37764d7c59 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.h
+++ b/drivers/gpu/drm/vkms/vkms_configfs.h
@@ -22,6 +22,7 @@ struct vkms_configfs_device {
 	struct config_group plane_group;
 	struct config_group crtc_group;
 	struct config_group encoder_group;
+	struct config_group connector_group;
 
 	struct mutex lock;
 	bool enabled;
@@ -53,6 +54,14 @@ struct vkms_configfs_encoder {
 	struct vkms_config_encoder *vkms_config_encoder;
 };
 
+struct vkms_configfs_connector {
+	struct config_group group;
+
+	struct config_group possible_encoder_group;
+	struct vkms_configfs_device *vkms_configfs_device;
+	struct vkms_config_connector *vkms_config_connector;
+};
+
 #define config_item_to_vkms_configfs_device(item) \
 	container_of(to_config_group((item)), struct vkms_configfs_device, group)
 
@@ -68,6 +77,9 @@ struct vkms_configfs_encoder {
 #define encoder_item_to_vkms_configfs_encoder(item) \
 	container_of(to_config_group((item)), struct vkms_configfs_encoder, group)
 
+#define connector_item_to_vkms_configfs_connector(item) \
+	container_of(to_config_group((item)), struct vkms_configfs_connector, group)
+
 #define plane_item_to_vkms_configfs_device(item) \
 	planes_item_to_vkms_configfs_device((item)->ci_parent)
 
@@ -89,14 +101,25 @@ struct vkms_configfs_encoder {
 #define encoder_item_to_vkms_configfs_device(item) \
 	config_item_to_vkms_configfs_device((item)->ci_parent)
 
+#define connector_item_to_vkms_configfs_device(item) \
+	config_item_to_vkms_configfs_device((item)->ci_parent)
+
 #define encoder_child_item_to_vkms_configfs_device(item) \
 	encoder_item_to_vkms_configfs_device((item)->ci_parent)
 
 #define encoder_possible_crtc_src_item_to_vkms_configfs_device(item) \
 	encoder_child_item_to_vkms_configfs_device((item)->ci_parent)
 
+#define connector_child_item_to_vkms_configfs_device(item) \
+	connector_item_to_vkms_configfs_device((item)->ci_parent)
+
+#define connector_possible_encoder_src_item_to_vkms_configfs_device(item) \
+	connector_child_item_to_vkms_configfs_device((item)->ci_parent)
+
 #define encoder_possible_crtc_src_item_to_vkms_configfs_encoder(item) \
 	encoder_item_to_vkms_configfs_encoder((item)->ci_parent)
+#define connector_possible_encoder_src_item_to_vkms_configfs_connector(item) \
+	connector_item_to_vkms_configfs_connector((item)->ci_parent)
 
 /* ConfigFS Support */
 int vkms_init_configfs(void);

-- 
2.47.1

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