[PATCH RFC 4/7] drm/vkms: Introduce plane rotation in ConfigFS

[Louis Chauvet <louis.chauvet@xxxxxxxxxxx>]

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`.

The current interface is:
/config/vkms
       	DEVICE_1
       	┣━ enable
       	┣━ planes
       	┃  ┗━ PLANE_1
       	┃     ┣━ type
       	┃     ┣━ supported_rotations
       	┃     ┗━ default_rotation
       	DEVICE_2
       	┗━ ditto

Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
---
 drivers/gpu/drm/vkms/vkms_configfs.c | 102 +++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index ee64243396b3..d121cf54e752 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -54,10 +54,112 @@ static ssize_t plane_type_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_rotations_show(struct config_item *item, char *page)
+{
+	struct vkms_config_plane *plane;
+	unsigned int plane_type;
+	struct vkms_configfs_device *vkms_configfs = plane_item_to_vkms_configfs_device(item);
+
+	mutex_lock(&vkms_configfs->lock);
+	plane = plane_item_to_vkms_configfs_plane(item)->vkms_config_plane;
+	plane_type = plane->supported_rotations;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return sprintf(page, "%u", plane_type);
+}
+
+static ssize_t plane_supported_rotations_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	struct vkms_config_plane *plane;
+	struct vkms_configfs_device *vkms_configfs = plane_item_to_vkms_configfs_device(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;
+
+	mutex_lock(&vkms_configfs->lock);
+
+	plane = plane_item_to_vkms_configfs_plane(item)->vkms_config_plane;
+
+	/* Ensures that the default rotation is included in supported rotation */
+	if (vkms_configfs->enabled || (val & plane->default_rotation) != plane->default_rotation) {
+		mutex_unlock(&vkms_configfs->lock);
+		return -EINVAL;
+	}
+
+	plane->supported_rotations = val;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return count;
+}
+
+static ssize_t plane_default_rotation_show(struct config_item *item, char *page)
+{
+	unsigned int plane_type;
+	struct vkms_config_plane *plane;
+	struct vkms_configfs_device *vkms_configfs = plane_item_to_vkms_configfs_device(item);
+
+	mutex_lock(&vkms_configfs->lock);
+	plane = plane_item_to_vkms_configfs_plane(item)->vkms_config_plane;
+	plane_type = plane->default_rotation;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return sprintf(page, "%u", plane_type);
+}
+
+static ssize_t plane_default_rotation_store(struct config_item *item,
+					    const char *page, size_t count)
+{
+	struct vkms_config_plane *plane;
+	struct vkms_configfs_device *vkms_configfs = plane_item_to_vkms_configfs_device(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;
+	mutex_lock(&vkms_configfs->lock);
+
+	plane = plane_item_to_vkms_configfs_plane(item)->vkms_config_plane;
+
+	/* Ensures that the default rotation is included in supported rotation */
+	if (vkms_configfs->enabled ||
+	    (val & plane->supported_rotations) != val) {
+		mutex_unlock(&vkms_configfs->lock);
+		return -EINVAL;
+	}
+	plane->default_rotation = val;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
+CONFIGFS_ATTR(plane_, supported_rotations);
+CONFIGFS_ATTR(plane_, default_rotation);
 
 static struct configfs_attribute *plane_attrs[] = {
 	&plane_attr_type,
+	&plane_attr_supported_rotations,
+	&plane_attr_default_rotation,
 	NULL,
 };
 

-- 
2.44.2