[PATCH 04/22] drm/vkms: Introduce configfs for plane rotation

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

To allows the userspace to test many hardware configuration, introduce a
new interface to configure the available rotation per planes. VKMS
supports any rotation and reflection, so the userspace can choose any
combination.

The supported rotations are configured by writing a rotation bitmask to
the file `supported_rotations` and the default rotation is chosen by
writing a rotation bitmask to `default_rotation`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/gpu/vkms.rst           |  7 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c | 94 ++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 3574e01b928d..a432968cc711 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,10 +87,15 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 1 configurable attribute:
+Planes have 3 configurable attribute:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
+- possible_rotations: Available rotation for a plane, as a bitmask: 0x01 no rotation,
+  0x02 rotate 90°, 0x04 rotate 180°, 0x08 rotate 270°, 0x10 reflect x, 0x20 reflect y
+  (same values as those exposed by the "rotation" property of a plane)
+- default_rotation: Default rotation presented to the userspace, same values as
+  possible_rotations.
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index ea245e2e2fd2..450e45e66a45 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -322,10 +322,104 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
 	return (ssize_t)count;
 }
 
+static ssize_t plane_supported_rotations_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int plane_supported_rotations;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		plane_supported_rotations = vkms_config_plane_get_supported_rotations(plane->config);
+	}
+
+	return sprintf(page, "%u", plane_supported_rotations);
+}
+
+static ssize_t plane_supported_rotations_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 0, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK))
+		return -EINVAL;
+	/* Should at least provide one rotation */
+	if (!(val & DRM_MODE_ROTATE_MASK))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		/* Ensures that the default rotation is included in supported rotation */
+		if (plane->dev->enabled ||
+		    (val & vkms_config_plane_get_default_rotation(plane->config)) !=
+		     vkms_config_plane_get_default_rotation(plane->config))
+			return -EINVAL;
+
+		vkms_config_plane_set_supported_rotations(plane->config, val);
+	}
+
+	return count;
+}
+
+static ssize_t plane_default_rotation_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int plane_default_rotation;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		plane_default_rotation = vkms_config_plane_get_default_rotation(plane->config);
+	}
+
+	return sprintf(page, "%u", plane_default_rotation);
+}
+
+static ssize_t plane_default_rotation_store(struct config_item *item,
+					    const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK))
+		return -EINVAL;
+	/* Should at least provide one rotation */
+	if ((val & DRM_MODE_ROTATE_MASK) == 0)
+		return -EINVAL;
+	/* Should contains only one rotation */
+	if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		/* Ensures that the default rotation is included in supported rotation */
+		if (plane->dev->enabled ||
+		    (val & vkms_config_plane_get_supported_rotations(plane->config)) != val)
+			return -EINVAL;
+
+		vkms_config_plane_set_default_rotation(plane->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
+CONFIGFS_ATTR(plane_, supported_rotations);
+CONFIGFS_ATTR(plane_, default_rotation);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
+	&plane_attr_supported_rotations,
+	&plane_attr_default_rotation,
 	NULL,
 };
 

-- 
2.51.0