[PATCH v6 00/16] drm/vkms: Add configfs support

[PATCH v6 00/16] drm/vkms: Add configfs support

[José Expósito]

Hi everyone,

This series allow to configure one or more VKMS instances without having
to reload the driver using configfs.

The process of configuring a VKMS device is documented in "vkms.rst".

In addition, I created a CLI tool to easily control VKMS instances from the
command line: vkmsctl [1].

The series is structured in 3 blocks:

  - Patches 1..11: Basic device configuration. For simplicity, I kept the
    available options as minimal as possible.

  - Patches 12 and 13: New option to skip the default device creation and to-do
    cleanup.

  - Patches 14, 15 and 16: Allow to hot-plug and unplug connectors. This is not
    part of the minimal set of options, but I included in this series so it can
    be used as a template/example of how new configurations can be added.

Finally, the code is thoroughly tested by a collection of IGT tests [2]. The IGT
series is almost fully reviewed (1 patch is missing) and it is waiting on this
series to be merged.

I don't know what is preventing this series to be ACK by a DRM maintainer, but
please, if there is something missing or that needs to be fixed let me know.

I CCed the configfs maintainers in case they can give feedback about the design
of the configfs API or the configfs related code, just in case that is one of
the complicated points to review by DRM maintainers.

Best wishes,
José Expósito

[1] https://github.com/JoseExposito/vkmsctl
[2] https://lore.kernel.org/igt-dev/20250807074550.6543-1-jose.exposito89@gmail.com/

Changes in v6:

  - No code changes, rebased on top of drm-misc-next
  - Added Tested-by: Mark Yacoub, who merged the series into the Android tree (thanks!)
    https://lore.kernel.org/dri-devel/CAC0gqY6ZH8h5aoNh31ck3dP6c3YYtfTRjJ47Obu6xSXSVXm5mA@mail.gmail.com/
  - Added a link in the cover letter the CLI to configure VKMS: vkmsctl
  - CCed more people to try to get the series merged
  - Link to v5: https://lore.kernel.org/dri-devel/20250507135431.53907-1-jose.exposito89@gmail.com/

Changes in v5:

  - No code changes, rebased on top of drm-misc-next
  - Added Reviewed-by tags, thanks Louis!
  - Link to v4: https://lore.kernel.org/dri-devel/20250407081425.6420-1-jose.exposito89@gmail.com/

Changes in v4:

  - No code changes, rebased on top of drm-misc-next
  - Since Louis and I worked on this together, set him as the author of some of
    the patches and me as co-developed-by to reflect this joint effort.
  - Link to v3: https://lore.kernel.org/all/20250307163353.5896-1-jose.exposito89@gmail.com/

Changes in v3:

  - Applied review comments by Louis Chauvet: (thanks!!)
    - Use scoped_guard() instead of guard(mutex)(...)
    - Fix a use-after-free error in the connector hot-plug code
  - Rebased on top of drm-misc-next
  - Link to v2: https://lore.kernel.org/all/20250225175936.7223-1-jose.exposito89@gmail.com/

Changes in v2:

  - Applied review comments by Louis Chauvet:
    - Use guard(mutex)(...) instead of lock/unlock
    - Return -EBUSY when trying to modify a enabled device
    - Move the connector hot-plug related patches to the end
  - Rebased on top of drm-misc-next
  - Link to v1: https://lore.kernel.org/dri-devel/20250218170808.9507-1-jose.exposito89@gmail.com/T/

José Expósito (6):
  drm/vkms: Expose device creation and destruction
  drm/vkms: Allow to configure the default device creation
  drm/vkms: Remove completed task from the TODO list
  drm/vkms: Allow to configure connector status
  drm/vkms: Allow to update the connector status
  drm/vkms: Allow to configure connector status via configfs

Louis Chauvet (10):
  drm/vkms: Add and remove VKMS instances via configfs
  drm/vkms: Allow to configure multiple planes via configfs
  drm/vkms: Allow to configure the plane type via configfs
  drm/vkms: Allow to configure multiple CRTCs via configfs
  drm/vkms: Allow to configure CRTC writeback support via configfs
  drm/vkms: Allow to attach planes and CRTCs via configfs
  drm/vkms: Allow to configure multiple encoders via configfs
  drm/vkms: Allow to attach encoders and CRTCs via configfs
  drm/vkms: Allow to configure multiple connectors via configfs
  drm/vkms: Allow to attach connectors and encoders via configfs

 Documentation/gpu/vkms.rst                    | 100 ++-
 drivers/gpu/drm/vkms/Kconfig                  |   1 +
 drivers/gpu/drm/vkms/Makefile                 |   3 +-
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  24 +
 drivers/gpu/drm/vkms/vkms_config.c            |   8 +-
 drivers/gpu/drm/vkms/vkms_config.h            |  26 +
 drivers/gpu/drm/vkms/vkms_configfs.c          | 833 ++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.h          |   8 +
 drivers/gpu/drm/vkms/vkms_connector.c         |  35 +
 drivers/gpu/drm/vkms/vkms_connector.h         |   9 +
 drivers/gpu/drm/vkms/vkms_drv.c               |  18 +-
 drivers/gpu/drm/vkms/vkms_drv.h               |  20 +
 12 files changed, 1072 insertions(+), 13 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.h


base-commit: 6b53cf48d9339c75fa51927b0a67d8a6751066bd
-- 
2.51.0

[PATCH v6 01/16] drm/vkms: Expose device creation and destruction

[José Expósito]

In preparation for configfs support, expose vkms_create() and
vkms_destroy().

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Co-developed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_drv.c |  4 ++--
 drivers/gpu/drm/vkms/vkms_drv.h | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index e8472d9b6e3b..78af37c7bd83 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -146,7 +146,7 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
 	return vkms_output_init(vkmsdev);
 }
 
-static int vkms_create(struct vkms_config *config)
+int vkms_create(struct vkms_config *config)
 {
 	int ret;
 	struct faux_device *fdev;
@@ -229,7 +229,7 @@ static int __init vkms_init(void)
 	return 0;
 }
 
-static void vkms_destroy(struct vkms_config *config)
+void vkms_destroy(struct vkms_config *config)
 {
 	struct faux_device *fdev;
 
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 8013c31efe3b..959ab48fbb47 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -258,6 +258,26 @@ struct vkms_device {
 #define to_vkms_plane_state(target)\
 	container_of(target, struct vkms_plane_state, base.base)
 
+/**
+ * vkms_create() - Create a device from a configuration
+ * @config: Config used to configure the new device
+ *
+ * A pointer to the created vkms_device is stored in @config
+ *
+ * Returns:
+ * 0 on success or an error.
+ */
+int vkms_create(struct vkms_config *config);
+
+/**
+ * vkms_destroy() - Destroy a device
+ * @config: Config from which the device was created
+ *
+ * The device is completely removed, but the @config is not freed. It can be
+ * reused or destroyed with vkms_config_destroy().
+ */
+void vkms_destroy(struct vkms_config *config);
+
 /**
  * vkms_crtc_init() - Initialize a CRTC for VKMS
  * @dev: DRM device associated with the VKMS buffer
-- 
2.51.0

[PATCH v6 02/16] drm/vkms: Add and remove VKMS instances via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Allow to create, enable, disable and destroy VKMS instances using
configfs.

For the moment, it is not possible to add pipeline items, so trying to
enable the device will fail printing an informative error to the log.

Tested-by: Mark Yacoub <markyacoub@google.com>
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           |  32 +++++
 drivers/gpu/drm/vkms/Kconfig         |   1 +
 drivers/gpu/drm/vkms/Makefile        |   3 +-
 drivers/gpu/drm/vkms/vkms_configfs.c | 172 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.h |   8 ++
 drivers/gpu/drm/vkms/vkms_drv.c      |   7 ++
 6 files changed, 222 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.h

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 8a8b1002931f..73521b9ff0c3 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -51,6 +51,38 @@ To disable the driver, use ::
 
   sudo modprobe -r vkms
 
+Configuring With Configfs
+=========================
+
+It is possible to create and configure multiple VKMS instances via configfs.
+
+Start by mounting configfs and loading VKMS::
+
+  sudo mount -t configfs none /config
+  sudo modprobe vkms
+
+Once VKMS is loaded, ``/config/vkms`` is created automatically. Each directory
+under ``/config/vkms`` represents a VKMS instance, create a new one::
+
+  sudo mkdir /config/vkms/my-vkms
+
+By default, the instance is disabled::
+
+  cat /config/vkms/my-vkms/enabled
+  0
+
+Once you are done configuring the VKMS instance, enable it::
+
+  echo "1" | sudo tee /config/vkms/my-vkms/enabled
+
+Finally, you can remove the VKMS instance disabling it::
+
+  echo "0" | sudo tee /config/vkms/my-vkms/enabled
+
+And removing the top level directory::
+
+  sudo rmdir /config/vkms/my-vkms
+
 Testing With IGT
 ================
 
diff --git a/drivers/gpu/drm/vkms/Kconfig b/drivers/gpu/drm/vkms/Kconfig
index 3c02f928ffe6..3977bbb99f7d 100644
--- a/drivers/gpu/drm/vkms/Kconfig
+++ b/drivers/gpu/drm/vkms/Kconfig
@@ -7,6 +7,7 @@ config DRM_VKMS
 	select DRM_KMS_HELPER
 	select DRM_GEM_SHMEM_HELPER
 	select CRC32
+	select CONFIGFS_FS
 	default n
 	help
 	  Virtual Kernel Mode-Setting (VKMS) is used for testing or for
diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
index d657865e573f..939991fc8233 100644
--- a/drivers/gpu/drm/vkms/Makefile
+++ b/drivers/gpu/drm/vkms/Makefile
@@ -8,7 +8,8 @@ vkms-y := \
 	vkms_composer.o \
 	vkms_writeback.o \
 	vkms_connector.o \
-	vkms_config.o
+	vkms_config.o \
+	vkms_configfs.o
 
 obj-$(CONFIG_DRM_VKMS) += vkms.o
 obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += tests/
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
new file mode 100644
index 000000000000..ee186952971b
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/cleanup.h>
+#include <linux/configfs.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include "vkms_drv.h"
+#include "vkms_config.h"
+#include "vkms_configfs.h"
+
+/* To avoid registering configfs more than once or unregistering on error */
+static bool is_configfs_registered;
+
+/**
+ * struct vkms_configfs_device - Configfs representation of a VKMS device
+ *
+ * @group: Top level configuration group that represents a VKMS device.
+ * Initialized when a new directory is created under "/config/vkms/"
+ * @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
+ * option changes
+ */
+struct vkms_configfs_device {
+	struct config_group group;
+
+	struct mutex lock;
+	struct vkms_config *config;
+	bool enabled;
+};
+
+#define device_item_to_vkms_configfs_device(item) \
+	container_of(to_config_group((item)), struct vkms_configfs_device, \
+		     group)
+
+static ssize_t device_enabled_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_device *dev;
+	bool enabled;
+
+	dev = device_item_to_vkms_configfs_device(item);
+
+	scoped_guard(mutex, &dev->lock)
+		enabled = dev->enabled;
+
+	return sprintf(page, "%d\n", enabled);
+}
+
+static ssize_t device_enabled_store(struct config_item *item, const char *page,
+				    size_t count)
+{
+	struct vkms_configfs_device *dev;
+	bool enabled;
+	int ret = 0;
+
+	dev = device_item_to_vkms_configfs_device(item);
+
+	if (kstrtobool(page, &enabled))
+		return -EINVAL;
+
+	scoped_guard(mutex, &dev->lock) {
+		if (!dev->enabled && enabled) {
+			if (!vkms_config_is_valid(dev->config))
+				return -EINVAL;
+
+			ret = vkms_create(dev->config);
+			if (ret)
+				return ret;
+		} else if (dev->enabled && !enabled) {
+			vkms_destroy(dev->config);
+		}
+
+		dev->enabled = enabled;
+	}
+
+	return (ssize_t)count;
+}
+
+CONFIGFS_ATTR(device_, enabled);
+
+static struct configfs_attribute *device_item_attrs[] = {
+	&device_attr_enabled,
+	NULL,
+};
+
+static void device_release(struct config_item *item)
+{
+	struct vkms_configfs_device *dev;
+
+	dev = device_item_to_vkms_configfs_device(item);
+
+	if (dev->enabled)
+		vkms_destroy(dev->config);
+
+	mutex_destroy(&dev->lock);
+	vkms_config_destroy(dev->config);
+	kfree(dev);
+}
+
+static struct configfs_item_operations device_item_operations = {
+	.release	= &device_release,
+};
+
+static const struct config_item_type device_item_type = {
+	.ct_attrs	= device_item_attrs,
+	.ct_item_ops	= &device_item_operations,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *make_device_group(struct config_group *group,
+					      const char *name)
+{
+	struct vkms_configfs_device *dev;
+
+	if (strcmp(name, DEFAULT_DEVICE_NAME) == 0)
+		return ERR_PTR(-EINVAL);
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->config = vkms_config_create(name);
+	if (IS_ERR(dev->config)) {
+		kfree(dev);
+		return ERR_CAST(dev->config);
+	}
+
+	config_group_init_type_name(&dev->group, name, &device_item_type);
+	mutex_init(&dev->lock);
+
+	return &dev->group;
+}
+
+static struct configfs_group_operations device_group_ops = {
+	.make_group = &make_device_group,
+};
+
+static const struct config_item_type device_group_type = {
+	.ct_group_ops	= &device_group_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct configfs_subsystem vkms_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_name = "vkms",
+			.ci_type = &device_group_type,
+		},
+	},
+	.su_mutex = __MUTEX_INITIALIZER(vkms_subsys.su_mutex),
+};
+
+int vkms_configfs_register(void)
+{
+	int ret;
+
+	if (is_configfs_registered)
+		return 0;
+
+	config_group_init(&vkms_subsys.su_group);
+	ret = configfs_register_subsystem(&vkms_subsys);
+
+	is_configfs_registered = ret == 0;
+
+	return ret;
+}
+
+void vkms_configfs_unregister(void)
+{
+	if (is_configfs_registered)
+		configfs_unregister_subsystem(&vkms_subsys);
+}
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h
new file mode 100644
index 000000000000..e9020b0043db
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_configfs.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _VKMS_CONFIGFS_H_
+#define _VKMS_CONFIGFS_H_
+
+int vkms_configfs_register(void);
+void vkms_configfs_unregister(void);
+
+#endif /* _VKMS_CONFIGFS_H_ */
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 78af37c7bd83..c1f23e6a4b07 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -28,6 +28,7 @@
 #include <drm/drm_vblank.h>
 
 #include "vkms_config.h"
+#include "vkms_configfs.h"
 #include "vkms_drv.h"
 
 #define DRIVER_NAME	"vkms"
@@ -214,6 +215,10 @@ static int __init vkms_init(void)
 	int ret;
 	struct vkms_config *config;
 
+	ret = vkms_configfs_register();
+	if (ret)
+		return ret;
+
 	config = vkms_config_default_create(enable_cursor, enable_writeback, enable_overlay);
 	if (IS_ERR(config))
 		return PTR_ERR(config);
@@ -250,6 +255,8 @@ void vkms_destroy(struct vkms_config *config)
 
 static void __exit vkms_exit(void)
 {
+	vkms_configfs_unregister();
+
 	if (!default_config)
 		return;
 
-- 
2.51.0

[PATCH v6 03/16] drm/vkms: Allow to configure multiple planes via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Create a default subgroup at /config/vkms/planes to allow to create as
many planes as required.

Tested-by: Mark Yacoub <markyacoub@google.com>
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           | 16 ++++-
 drivers/gpu/drm/vkms/vkms_configfs.c | 88 ++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 73521b9ff0c3..c0c892e4e27c 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -71,6 +71,19 @@ By default, the instance is disabled::
   cat /config/vkms/my-vkms/enabled
   0
 
+And directories are created for each configurable item of the display pipeline::
+
+  tree /config/vkms/my-vkms
+  ├── enabled
+  └── planes
+
+To add items to the display pipeline, create one or more directories under the
+available paths.
+
+Start by creating one or more planes::
+
+  sudo mkdir /config/vkms/my-vkms/planes/plane0
+
 Once you are done configuring the VKMS instance, enable it::
 
   echo "1" | sudo tee /config/vkms/my-vkms/enabled
@@ -79,8 +92,9 @@ Finally, you can remove the VKMS instance disabling it::
 
   echo "0" | sudo tee /config/vkms/my-vkms/enabled
 
-And removing the top level directory::
+And removing the top level directory and its subdirectories::
 
+  sudo rmdir /config/vkms/my-vkms/planes/*
   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 ee186952971b..a7c705e00e4c 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -16,6 +16,7 @@ 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"
  * @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
@@ -23,16 +24,99 @@ static bool is_configfs_registered;
  */
 struct vkms_configfs_device {
 	struct config_group group;
+	struct config_group planes_group;
 
 	struct mutex lock;
 	struct vkms_config *config;
 	bool enabled;
 };
 
+/**
+ * struct vkms_configfs_plane - Configfs representation of a plane
+ *
+ * @group: Top level configuration group that represents a plane.
+ * Initialized when a new directory is created under "/config/vkms/planes"
+ * @dev: The vkms_configfs_device this plane belongs to
+ * @config: Configuration of the VKMS plane
+ */
+struct vkms_configfs_plane {
+	struct config_group group;
+	struct vkms_configfs_device *dev;
+	struct vkms_config_plane *config;
+};
+
 #define device_item_to_vkms_configfs_device(item) \
 	container_of(to_config_group((item)), struct vkms_configfs_device, \
 		     group)
 
+#define child_group_to_vkms_configfs_device(group) \
+	device_item_to_vkms_configfs_device((&(group)->cg_item)->ci_parent)
+
+#define plane_item_to_vkms_configfs_plane(item) \
+	container_of(to_config_group((item)), struct vkms_configfs_plane, group)
+
+static void plane_release(struct config_item *item)
+{
+	struct vkms_configfs_plane *plane;
+	struct mutex *lock;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+	lock = &plane->dev->lock;
+
+	scoped_guard(mutex, lock) {
+		vkms_config_destroy_plane(plane->config);
+		kfree(plane);
+	}
+}
+
+static struct configfs_item_operations plane_item_operations = {
+	.release	= &plane_release,
+};
+
+static const struct config_item_type plane_item_type = {
+	.ct_item_ops	= &plane_item_operations,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *make_plane_group(struct config_group *group,
+					     const char *name)
+{
+	struct vkms_configfs_device *dev;
+	struct vkms_configfs_plane *plane;
+
+	dev = child_group_to_vkms_configfs_device(group);
+
+	scoped_guard(mutex, &dev->lock) {
+		if (dev->enabled)
+			return ERR_PTR(-EBUSY);
+
+		plane = kzalloc(sizeof(*plane), GFP_KERNEL);
+		if (!plane)
+			return ERR_PTR(-ENOMEM);
+
+		plane->dev = dev;
+
+		plane->config = vkms_config_create_plane(dev->config);
+		if (IS_ERR(plane->config)) {
+			kfree(plane);
+			return ERR_CAST(plane->config);
+		}
+
+		config_group_init_type_name(&plane->group, name, &plane_item_type);
+	}
+
+	return &plane->group;
+}
+
+static struct configfs_group_operations planes_group_operations = {
+	.make_group	= &make_plane_group,
+};
+
+static const struct config_item_type plane_group_type = {
+	.ct_group_ops	= &planes_group_operations,
+	.ct_owner	= THIS_MODULE,
+};
+
 static ssize_t device_enabled_show(struct config_item *item, char *page)
 {
 	struct vkms_configfs_device *dev;
@@ -128,6 +212,10 @@ static struct config_group *make_device_group(struct config_group *group,
 	config_group_init_type_name(&dev->group, name, &device_item_type);
 	mutex_init(&dev->lock);
 
+	config_group_init_type_name(&dev->planes_group, "planes",
+				    &plane_group_type);
+	configfs_add_default_group(&dev->planes_group, &dev->group);
+
 	return &dev->group;
 }
 
-- 
2.51.0

[PATCH v6 04/16] drm/vkms: Allow to configure the plane type via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

When a plane is created, add a `type` file to allow to set the type:

 - 0 overlay
 - 1 primary
 - 2 cursor

Tested-by: Mark Yacoub <markyacoub@google.com>
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           |  5 +++
 drivers/gpu/drm/vkms/vkms_configfs.c | 46 ++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index c0c892e4e27c..dd880ce6811c 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -84,6 +84,11 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
+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)
+
 Once you are done configuring the VKMS instance, enable it::
 
   echo "1" | sudo tee /config/vkms/my-vkms/enabled
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index a7c705e00e4c..398755127759 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -55,6 +55,51 @@ struct vkms_configfs_plane {
 #define plane_item_to_vkms_configfs_plane(item) \
 	container_of(to_config_group((item)), struct vkms_configfs_plane, group)
 
+static ssize_t plane_type_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	enum drm_plane_type type;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		type = vkms_config_plane_get_type(plane->config);
+
+	return sprintf(page, "%u", type);
+}
+
+static ssize_t plane_type_store(struct config_item *item, const char *page,
+				size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	enum drm_plane_type type;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtouint(page, 10, &type))
+		return -EINVAL;
+
+	if (type != DRM_PLANE_TYPE_OVERLAY && type != DRM_PLANE_TYPE_PRIMARY &&
+	    type != DRM_PLANE_TYPE_CURSOR)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_type(plane->config, type);
+	}
+
+	return (ssize_t)count;
+}
+
+CONFIGFS_ATTR(plane_, type);
+
+static struct configfs_attribute *plane_item_attrs[] = {
+	&plane_attr_type,
+	NULL,
+};
+
 static void plane_release(struct config_item *item)
 {
 	struct vkms_configfs_plane *plane;
@@ -74,6 +119,7 @@ static struct configfs_item_operations plane_item_operations = {
 };
 
 static const struct config_item_type plane_item_type = {
+	.ct_attrs	= plane_item_attrs,
 	.ct_item_ops	= &plane_item_operations,
 	.ct_owner	= THIS_MODULE,
 };
-- 
2.51.0

[PATCH v6 05/16] drm/vkms: Allow to configure multiple CRTCs via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Create a default subgroup at /config/vkms/crtcs to allow to create as
many CRTCs as required.

Tested-by: Mark Yacoub <markyacoub@google.com>
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 | 85 ++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index dd880ce6811c..7396447b5e58 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
+  ├── 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
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 398755127759..62a82366791d 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -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;
 }
 
-- 
2.51.0

[PATCH v6 06/16] drm/vkms: Allow to configure CRTC writeback support via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

When a CRTC is created, add a `writeback` file to allow to enable or
disable writeback connector support

Tested-by: Mark Yacoub <markyacoub@google.com>
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           |  4 +++
 drivers/gpu/drm/vkms/vkms_configfs.c | 42 ++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 7396447b5e58..9f76918bb1d1 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -94,6 +94,10 @@ Continue by creating one or more CRTCs::
 
   sudo mkdir /config/vkms/my-vkms/crtcs/crtc0
 
+CRTCs have 1 configurable attribute:
+
+- writeback: Enable or disable writeback connector support by writing 1 or 0
+
 Once you are done configuring the VKMS instance, enable it::
 
   echo "1" | sudo tee /config/vkms/my-vkms/enabled
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 62a82366791d..e9f445043268 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -74,6 +74,47 @@ struct vkms_configfs_crtc {
 #define crtc_item_to_vkms_configfs_crtc(item) \
 	container_of(to_config_group((item)), struct vkms_configfs_crtc, group)
 
+static ssize_t crtc_writeback_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_crtc *crtc;
+	bool writeback;
+
+	crtc = crtc_item_to_vkms_configfs_crtc(item);
+
+	scoped_guard(mutex, &crtc->dev->lock)
+		writeback = vkms_config_crtc_get_writeback(crtc->config);
+
+	return sprintf(page, "%d\n", writeback);
+}
+
+static ssize_t crtc_writeback_store(struct config_item *item, const char *page,
+				    size_t count)
+{
+	struct vkms_configfs_crtc *crtc;
+	bool writeback;
+
+	crtc = crtc_item_to_vkms_configfs_crtc(item);
+
+	if (kstrtobool(page, &writeback))
+		return -EINVAL;
+
+	scoped_guard(mutex, &crtc->dev->lock) {
+		if (crtc->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_crtc_set_writeback(crtc->config, writeback);
+	}
+
+	return (ssize_t)count;
+}
+
+CONFIGFS_ATTR(crtc_, writeback);
+
+static struct configfs_attribute *crtc_item_attrs[] = {
+	&crtc_attr_writeback,
+	NULL,
+};
+
 static void crtc_release(struct config_item *item)
 {
 	struct vkms_configfs_crtc *crtc;
@@ -93,6 +134,7 @@ static struct configfs_item_operations crtc_item_operations = {
 };
 
 static const struct config_item_type crtc_item_type = {
+	.ct_attrs	= crtc_item_attrs,
 	.ct_item_ops	= &crtc_item_operations,
 	.ct_owner	= THIS_MODULE,
 };
-- 
2.51.0

[PATCH v6 07/16] drm/vkms: Allow to attach planes and CRTCs via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

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: Mark Yacoub <markyacoub@google.com>
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           |  9 +++++
 drivers/gpu/drm/vkms/vkms_configfs.c | 58 ++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 9f76918bb1d1..c79fca3d3a11 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -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
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index e9f445043268..2cf97c2b6203 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -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;
-- 
2.51.0

[PATCH v6 08/16] drm/vkms: Allow to configure multiple encoders via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Create a default subgroup at /config/vkms/encoders to allow to create as
many encoders as required.

Tested-by: Mark Yacoub <markyacoub@google.com>
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 c79fca3d3a11..622fbfa12a84 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -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
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 2cf97c2b6203..0df86e63570a 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -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;
 }
 
-- 
2.51.0

[PATCH v6 09/16] drm/vkms: Allow to attach encoders and CRTCs via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

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

Tested-by: Mark Yacoub <markyacoub@google.com>
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           |  2 +
 drivers/gpu/drm/vkms/vkms_configfs.c | 58 ++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 622fbfa12a84..585effe90550 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -106,6 +106,7 @@ Next, create one or more encoders::
 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
+  sudo ln -s /config/vkms/my-vkms/crtcs/crtc0 /config/vkms/my-vkms/encoders/encoder0/possible_crtcs
 
 Since at least one primary plane is required, make sure to set the right type::
 
@@ -122,6 +123,7 @@ 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 rm /config/vkms/my-vkms/encoders/*/possible_crtcs/*
   sudo rmdir /config/vkms/my-vkms/planes/*
   sudo rmdir /config/vkms/my-vkms/crtcs/*
   sudo rmdir /config/vkms/my-vkms/encoders/*
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 0df86e63570a..7de601e39d2b 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -70,11 +70,13 @@ struct vkms_configfs_crtc {
  *
  * @group: Top level configuration group that represents a encoder.
  * Initialized when a new directory is created under "/config/vkms/encoders"
+ * @possible_crtcs_group: Default subgroup of @group at "encoder/possible_crtcs"
  * @dev: The vkms_configfs_device this encoder belongs to
  * @config: Configuration of the VKMS encoder
  */
 struct vkms_configfs_encoder {
 	struct config_group group;
+	struct config_group possible_crtcs_group;
 	struct vkms_configfs_device *dev;
 	struct vkms_config_encoder *config;
 };
@@ -100,6 +102,10 @@ struct vkms_configfs_encoder {
 	container_of(to_config_group((item)), struct vkms_configfs_encoder, \
 		     group)
 
+#define encoder_possible_crtcs_item_to_vkms_configfs_encoder(item) \
+	container_of(to_config_group((item)), struct vkms_configfs_encoder, \
+		     possible_crtcs_group)
+
 static ssize_t crtc_writeback_show(struct config_item *item, char *page)
 {
 	struct vkms_configfs_crtc *crtc;
@@ -364,6 +370,52 @@ static const struct config_item_type plane_group_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
+static int encoder_possible_crtcs_allow_link(struct config_item *src,
+					     struct config_item *target)
+{
+	struct vkms_configfs_encoder *encoder;
+	struct vkms_configfs_crtc *crtc;
+	int ret;
+
+	if (target->ci_type != &crtc_item_type)
+		return -EINVAL;
+
+	encoder = encoder_possible_crtcs_item_to_vkms_configfs_encoder(src);
+	crtc = crtc_item_to_vkms_configfs_crtc(target);
+
+	scoped_guard(mutex, &encoder->dev->lock) {
+		if (encoder->dev->enabled)
+			return -EBUSY;
+
+		ret = vkms_config_encoder_attach_crtc(encoder->config, crtc->config);
+	}
+
+	return ret;
+}
+
+static void encoder_possible_crtcs_drop_link(struct config_item *src,
+					     struct config_item *target)
+{
+	struct vkms_configfs_encoder *encoder;
+	struct vkms_configfs_crtc *crtc;
+
+	encoder = encoder_possible_crtcs_item_to_vkms_configfs_encoder(src);
+	crtc = crtc_item_to_vkms_configfs_crtc(target);
+
+	scoped_guard(mutex, &encoder->dev->lock)
+		vkms_config_encoder_detach_crtc(encoder->config, crtc->config);
+}
+
+static struct configfs_item_operations encoder_possible_crtcs_item_operations = {
+	.allow_link	= encoder_possible_crtcs_allow_link,
+	.drop_link	= encoder_possible_crtcs_drop_link,
+};
+
+static const struct config_item_type encoder_possible_crtcs_group_type = {
+	.ct_item_ops	= &encoder_possible_crtcs_item_operations,
+	.ct_owner	= THIS_MODULE,
+};
+
 static void encoder_release(struct config_item *item)
 {
 	struct vkms_configfs_encoder *encoder;
@@ -413,6 +465,12 @@ static struct config_group *make_encoder_group(struct config_group *group,
 
 		config_group_init_type_name(&encoder->group, name,
 					    &encoder_item_type);
+
+		config_group_init_type_name(&encoder->possible_crtcs_group,
+					    "possible_crtcs",
+					    &encoder_possible_crtcs_group_type);
+		configfs_add_default_group(&encoder->possible_crtcs_group,
+					   &encoder->group);
 	}
 
 	return &encoder->group;
-- 
2.51.0

[PATCH v6 10/16] drm/vkms: Allow to configure multiple connectors via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Create a default subgroup at
/config/vkms/connectors to allow to create as many connectors as
required.

Tested-by: Mark Yacoub <markyacoub@google.com>
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 585effe90550..b799102d54ac 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;
 }
 
-- 
2.51.0

[PATCH v6 11/16] drm/vkms: Allow to attach connectors and encoders via configfs

[José Expósito]

From: Louis Chauvet <louis.chauvet@bootlin.com>

Create a default subgroup at
/config/vkms/connectors/connector/possible_encoders that will contain
symbolic links to the possible encoders for the connector.

Tested-by: Mark Yacoub <markyacoub@google.com>
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           |  2 +
 drivers/gpu/drm/vkms/vkms_configfs.c | 62 ++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index b799102d54ac..31a3880ad83c 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -112,6 +112,7 @@ 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
   sudo ln -s /config/vkms/my-vkms/crtcs/crtc0 /config/vkms/my-vkms/encoders/encoder0/possible_crtcs
+  sudo ln -s /config/vkms/my-vkms/encoders/encoder0 /config/vkms/my-vkms/connectors/connector0/possible_encoders
 
 Since at least one primary plane is required, make sure to set the right type::
 
@@ -129,6 +130,7 @@ And removing the top level directory and its subdirectories::
 
   sudo rm /config/vkms/my-vkms/planes/*/possible_crtcs/*
   sudo rm /config/vkms/my-vkms/encoders/*/possible_crtcs/*
+  sudo rm /config/vkms/my-vkms/connectors/*/possible_encoders/*
   sudo rmdir /config/vkms/my-vkms/planes/*
   sudo rmdir /config/vkms/my-vkms/crtcs/*
   sudo rmdir /config/vkms/my-vkms/encoders/*
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 692e1b708012..8e90acbebd6a 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -88,11 +88,14 @@ struct vkms_configfs_encoder {
  *
  * @group: Top level configuration group that represents a connector.
  * Initialized when a new directory is created under "/config/vkms/connectors"
+ * @possible_encoders_group: Default subgroup of @group at
+ * "connector/possible_encoders"
  * @dev: The vkms_configfs_device this connector belongs to
  * @config: Configuration of the VKMS connector
  */
 struct vkms_configfs_connector {
 	struct config_group group;
+	struct config_group possible_encoders_group;
 	struct vkms_configfs_device *dev;
 	struct vkms_config_connector *config;
 };
@@ -126,6 +129,10 @@ struct vkms_configfs_connector {
 	container_of(to_config_group((item)), struct vkms_configfs_connector, \
 		     group)
 
+#define connector_possible_encoders_item_to_vkms_configfs_connector(item) \
+	container_of(to_config_group((item)), struct vkms_configfs_connector, \
+		     possible_encoders_group)
+
 static ssize_t crtc_writeback_show(struct config_item *item, char *page)
 {
 	struct vkms_configfs_crtc *crtc;
@@ -528,6 +535,55 @@ static const struct config_item_type connector_item_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
+static int connector_possible_encoders_allow_link(struct config_item *src,
+						  struct config_item *target)
+{
+	struct vkms_configfs_connector *connector;
+	struct vkms_configfs_encoder *encoder;
+	int ret;
+
+	if (target->ci_type != &encoder_item_type)
+		return -EINVAL;
+
+	connector = connector_possible_encoders_item_to_vkms_configfs_connector(src);
+	encoder = encoder_item_to_vkms_configfs_encoder(target);
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		if (connector->dev->enabled)
+			return -EBUSY;
+
+		ret = vkms_config_connector_attach_encoder(connector->config,
+							   encoder->config);
+	}
+
+	return ret;
+}
+
+static void connector_possible_encoders_drop_link(struct config_item *src,
+						  struct config_item *target)
+{
+	struct vkms_configfs_connector *connector;
+	struct vkms_configfs_encoder *encoder;
+
+	connector = connector_possible_encoders_item_to_vkms_configfs_connector(src);
+	encoder = encoder_item_to_vkms_configfs_encoder(target);
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		vkms_config_connector_detach_encoder(connector->config,
+						     encoder->config);
+	}
+}
+
+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 const struct config_item_type connector_possible_encoders_group_type = {
+	.ct_item_ops	= &connector_possible_encoders_item_operations,
+	.ct_owner	= THIS_MODULE,
+};
+
 static struct config_group *make_connector_group(struct config_group *group,
 						 const char *name)
 {
@@ -554,6 +610,12 @@ static struct config_group *make_connector_group(struct config_group *group,
 
 		config_group_init_type_name(&connector->group, name,
 					    &connector_item_type);
+
+		config_group_init_type_name(&connector->possible_encoders_group,
+					    "possible_encoders",
+					    &connector_possible_encoders_group_type);
+		configfs_add_default_group(&connector->possible_encoders_group,
+					   &connector->group);
 	}
 
 	return &connector->group;
-- 
2.51.0

[PATCH v6 12/16] drm/vkms: Allow to configure the default device creation

[José Expósito]

Add a new module param to allow to create or not the default VKMS
instance. Useful when combined with configfs to avoid having additional
VKMS instances.

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_drv.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index c1f23e6a4b07..6d299903fab2 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -50,6 +50,10 @@ static bool enable_overlay;
 module_param_named(enable_overlay, enable_overlay, bool, 0444);
 MODULE_PARM_DESC(enable_overlay, "Enable/Disable overlay support");
 
+static bool create_default_dev = true;
+module_param_named(create_default_dev, create_default_dev, bool, 0444);
+MODULE_PARM_DESC(create_default_dev, "Create or not the default VKMS device");
+
 DEFINE_DRM_GEM_FOPS(vkms_driver_fops);
 
 static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
@@ -219,6 +223,9 @@ static int __init vkms_init(void)
 	if (ret)
 		return ret;
 
+	if (!create_default_dev)
+		return 0;
+
 	config = vkms_config_default_create(enable_cursor, enable_writeback, enable_overlay);
 	if (IS_ERR(config))
 		return PTR_ERR(config);
-- 
2.51.0

[PATCH v6 13/16] drm/vkms: Remove completed task from the TODO list

[José Expósito]

Remove the configfs related TODO items from the "Runtime Configuration"
section.

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 Documentation/gpu/vkms.rst | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 31a3880ad83c..364b574a8cae 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -233,21 +233,14 @@ Runtime Configuration
 ---------------------
 
 We want to be able to reconfigure vkms instance without having to reload the
-module. Use/Test-cases:
+module through configfs. Use/Test-cases:
 
 - Hotplug/hotremove connectors on the fly (to be able to test DP MST handling
   of compositors).
 
-- Configure planes/crtcs/connectors (we'd need some code to have more than 1 of
-  them first).
-
 - Change output configuration: Plug/unplug screens, change EDID, allow changing
   the refresh rate.
 
-The currently proposed solution is to expose vkms configuration through
-configfs. All existing module options should be supported through configfs
-too.
-
 Writeback support
 -----------------
 
-- 
2.51.0

[PATCH v6 14/16] drm/vkms: Allow to configure connector status

[José Expósito]

Allow to store the connector status in vkms_config_connector and add a
getter and a setter functions as well a KUnit test.

This change only adds the configuration, the connector status is not
used yet.

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c | 24 +++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.c            |  8 ++++--
 drivers/gpu/drm/vkms/vkms_config.h            | 26 +++++++++++++++++++
 3 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index ff4566cf9925..3574a829a6ed 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -916,6 +916,29 @@ static void vkms_config_test_connector_get_possible_encoders(struct kunit *test)
 	vkms_config_destroy(config);
 }
 
+static void vkms_config_test_connector_status(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_connector *connector_cfg;
+	enum drm_connector_status status;
+
+	config = vkms_config_create("test");
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	connector_cfg = vkms_config_create_connector(config);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, connector_cfg);
+
+	status = vkms_config_connector_get_status(connector_cfg);
+	KUNIT_EXPECT_EQ(test, status, connector_status_connected);
+
+	vkms_config_connector_set_status(connector_cfg,
+					 connector_status_disconnected);
+	status = vkms_config_connector_get_status(connector_cfg);
+	KUNIT_EXPECT_EQ(test, status, connector_status_disconnected);
+
+	vkms_config_destroy(config);
+}
+
 static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_empty_config),
 	KUNIT_CASE_PARAM(vkms_config_test_default_config,
@@ -937,6 +960,7 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_plane_get_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_encoder_get_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_connector_get_possible_encoders),
+	KUNIT_CASE(vkms_config_test_connector_status),
 	{}
 };
 
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index a1df5659b0fb..f8394a063ecf 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -361,8 +361,11 @@ static int vkms_config_show(struct seq_file *m, void *data)
 	vkms_config_for_each_encoder(vkmsdev->config, encoder_cfg)
 		seq_puts(m, "encoder\n");
 
-	vkms_config_for_each_connector(vkmsdev->config, connector_cfg)
-		seq_puts(m, "connector\n");
+	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
+		seq_puts(m, "connector:\n");
+		seq_printf(m, "\tstatus=%d\n",
+			   vkms_config_connector_get_status(connector_cfg));
+	}
 
 	return 0;
 }
@@ -588,6 +591,7 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *c
 		return ERR_PTR(-ENOMEM);
 
 	connector_cfg->config = config;
+	connector_cfg->status = connector_status_connected;
 	xa_init_flags(&connector_cfg->possible_encoders, XA_FLAGS_ALLOC);
 
 	list_add_tail(&connector_cfg->link, &config->connectors);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 0118e3f99706..e202b5a84ddd 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -7,6 +7,8 @@
 #include <linux/types.h>
 #include <linux/xarray.h>
 
+#include <drm/drm_connector.h>
+
 #include "vkms_drv.h"
 
 /**
@@ -99,6 +101,7 @@ struct vkms_config_encoder {
  *
  * @link: Link to the others connector in vkms_config
  * @config: The vkms_config this connector belongs to
+ * @status: Status (connected, disconnected...) of the connector
  * @possible_encoders: Array of encoders that can be used with this connector
  * @connector: Internal usage. This pointer should never be considered as valid.
  *             It can be used to store a temporary reference to a VKMS connector
@@ -109,6 +112,7 @@ struct vkms_config_connector {
 	struct list_head link;
 	struct vkms_config *config;
 
+	enum drm_connector_status status;
 	struct xarray possible_encoders;
 
 	/* Internal usage */
@@ -434,4 +438,26 @@ int __must_check vkms_config_connector_attach_encoder(struct vkms_config_connect
 void vkms_config_connector_detach_encoder(struct vkms_config_connector *connector_cfg,
 					  struct vkms_config_encoder *encoder_cfg);
 
+/**
+ * vkms_config_connector_get_status() - Return the status of the connector
+ * @connector_cfg: Connector to get the status from
+ */
+static inline enum drm_connector_status
+vkms_config_connector_get_status(struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->status;
+}
+
+/**
+ * vkms_config_crtc_set_writeback() - If a writeback connector will be created
+ * @crtc_cfg: Target CRTC
+ * @writeback: Enable or disable the writeback connector
+ */
+static inline void
+vkms_config_connector_set_status(struct vkms_config_connector *connector_cfg,
+				 enum drm_connector_status status)
+{
+	connector_cfg->status = status;
+}
+
 #endif /* _VKMS_CONFIG_H_ */
-- 
2.51.0

[PATCH v6 15/16] drm/vkms: Allow to update the connector status

[José Expósito]

Implement the drm_connector_funcs.detect() callback to update the
connector status by returning the status stored in the configuration.

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 drivers/gpu/drm/vkms/vkms_connector.c | 28 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.h |  3 +++
 2 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 48b10cba322a..89fa8d9d739b 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -5,9 +5,37 @@
 #include <drm/drm_managed.h>
 #include <drm/drm_probe_helper.h>
 
+#include "vkms_config.h"
 #include "vkms_connector.h"
 
+static enum drm_connector_status vkms_connector_detect(struct drm_connector *connector,
+						       bool force)
+{
+	struct drm_device *dev = connector->dev;
+	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
+	struct vkms_connector *vkms_connector;
+	enum drm_connector_status status;
+	struct vkms_config_connector *connector_cfg;
+
+	vkms_connector = drm_connector_to_vkms_connector(connector);
+
+	/*
+	 * The connector configuration might not exist if its configfs directory
+	 * was deleted. Therefore, use the configuration if present or keep the
+	 * current status if we can not access it anymore.
+	 */
+	status = connector->status;
+
+	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
+		if (connector_cfg->connector == vkms_connector)
+			status = vkms_config_connector_get_status(connector_cfg);
+	}
+
+	return status;
+}
+
 static const struct drm_connector_funcs vkms_connector_funcs = {
+	.detect = vkms_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.reset = drm_atomic_helper_connector_reset,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
index c9149c1b7af0..90f835f70b3b 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.h
+++ b/drivers/gpu/drm/vkms/vkms_connector.h
@@ -5,6 +5,9 @@
 
 #include "vkms_drv.h"
 
+#define drm_connector_to_vkms_connector(target) \
+	container_of(target, struct vkms_connector, base)
+
 /**
  * struct vkms_connector - VKMS custom type wrapping around the DRM connector
  *
-- 
2.51.0

[PATCH v6 16/16] drm/vkms: Allow to configure connector status via configfs

[José Expósito]

When a connector is created, add a `status` file to allow to update the
connector status to:

 - 1 connector_status_connected
 - 2 connector_status_disconnected
 - 3 connector_status_unknown

If the device is enabled, updating the status hot-plug or unplugs the
connector.

Tested-by: Mark Yacoub <markyacoub@google.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
---
 Documentation/gpu/vkms.rst            |  5 +++
 drivers/gpu/drm/vkms/vkms_configfs.c  | 48 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c |  7 ++++
 drivers/gpu/drm/vkms/vkms_connector.h |  6 ++++
 4 files changed, 66 insertions(+)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 364b574a8cae..3574e01b928d 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -108,6 +108,11 @@ Last but not least, create one or more connectors::
 
   sudo mkdir /config/vkms/my-vkms/connectors/connector0
 
+Connectors have 1 configurable attribute:
+
+- status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
+  as those exposed by the "status" property of a connector)
+
 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
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 8e90acbebd6a..07ab794e1052 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -7,6 +7,7 @@
 #include "vkms_drv.h"
 #include "vkms_config.h"
 #include "vkms_configfs.h"
+#include "vkms_connector.h"
 
 /* To avoid registering configfs more than once or unregistering on error */
 static bool is_configfs_registered;
@@ -512,6 +513,52 @@ static const struct config_item_type encoder_group_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
+static ssize_t connector_status_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	enum drm_connector_status status;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+		status = vkms_config_connector_get_status(connector->config);
+
+	return sprintf(page, "%u", status);
+}
+
+static ssize_t connector_status_store(struct config_item *item,
+				      const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	enum drm_connector_status status;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	if (kstrtouint(page, 10, &status))
+		return -EINVAL;
+
+	if (status != connector_status_connected &&
+	    status != connector_status_disconnected &&
+	    status != connector_status_unknown)
+		return -EINVAL;
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		vkms_config_connector_set_status(connector->config, status);
+
+		if (connector->dev->enabled)
+			vkms_trigger_connector_hotplug(connector->dev->config->dev);
+	}
+
+	return (ssize_t)count;
+}
+
+CONFIGFS_ATTR(connector_, status);
+
+static struct configfs_attribute *connector_item_attrs[] = {
+	&connector_attr_status,
+	NULL,
+};
+
 static void connector_release(struct config_item *item)
 {
 	struct vkms_configfs_connector *connector;
@@ -531,6 +578,7 @@ static struct configfs_item_operations connector_item_operations = {
 };
 
 static const struct config_item_type connector_item_type = {
+	.ct_attrs	= connector_item_attrs,
 	.ct_item_ops	= &connector_item_operations,
 	.ct_owner	= THIS_MODULE,
 };
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 89fa8d9d739b..b0a6b212d3f4 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -87,3 +87,10 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev)
 
 	return connector;
 }
+
+void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev)
+{
+	struct drm_device *dev = &vkmsdev->drm;
+
+	drm_kms_helper_hotplug_event(dev);
+}
diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
index 90f835f70b3b..35f2adf97e32 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.h
+++ b/drivers/gpu/drm/vkms/vkms_connector.h
@@ -26,4 +26,10 @@ struct vkms_connector {
  */
 struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev);
 
+/**
+ * struct vkms_device *vkmsdev() - Update the device's connectors status
+ * @vkmsdev: VKMS device to update
+ */
+void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev);
+
 #endif /* _VKMS_CONNECTOR_H_ */
-- 
2.51.0