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

The supported color encoding are configured by writing a color encoding
bitmask to the file `supported_color_encoding` and the default color
encoding is chosen by writing a color encoding bitmask to
`default_color_encoding`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/gpu/vkms.rst           |  7 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c | 98 ++++++++++++++++++++++++++++++++++++
 2 files changed, 104 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index eac1a942d6c4..dab6811687a2 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,7 +87,7 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 4 configurable attributes:
+Planes have 6 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
@@ -97,6 +97,11 @@ Planes have 4 configurable attributes:
   (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.
+- supported_color_encoding: Available encoding for a plane, as a bitmask:
+  0x01 YCBCR_BT601, 0x02: YCBCR_BT709, 0x04 YCBCR_BT2020 (same values as those exposed
+  by the COLOR_ENCODING property of a plane)
+- default_color_encoding: Default color encoding presented to the userspace, same
+  values as supported_color_encoding
 
 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 7cc8ba315ef0..ee2e8d141f9e 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -439,16 +439,114 @@ static ssize_t plane_default_rotation_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_color_encodings_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int supported_color_encoding;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		supported_color_encoding = vkms_config_plane_get_supported_color_encodings(plane->config);
+	}
+
+	return sprintf(page, "%u", supported_color_encoding);
+}
+
+static ssize_t plane_supported_color_encodings_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 & ~(BIT(DRM_COLOR_YCBCR_BT601) |
+		    BIT(DRM_COLOR_YCBCR_BT709) |
+		    BIT(DRM_COLOR_YCBCR_BT2020)))
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & (BIT(DRM_COLOR_YCBCR_BT601) |
+		    BIT(DRM_COLOR_YCBCR_BT709) |
+		    BIT(DRM_COLOR_YCBCR_BT2020))) == 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		/* Ensures that the default rotation is included in supported rotation */
+		if (plane->dev->enabled)
+			return -EINVAL;
+
+		vkms_config_plane_set_supported_color_encodings(plane->config, val);
+	}
+
+	return count;
+}
+
+/* Plane default_color_encoding : vkms/<device>/planes/<plane>/default_color_encoding */
+
+static ssize_t plane_default_color_encoding_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int default_color_encoding;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		default_color_encoding = vkms_config_plane_get_default_color_encoding(plane->config);
+	}
+
+	return sprintf(page, "%u", default_color_encoding);
+}
+
+static ssize_t plane_default_color_encoding_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 & ~(BIT(DRM_COLOR_YCBCR_BT601) |
+		    BIT(DRM_COLOR_YCBCR_BT709) |
+		    BIT(DRM_COLOR_YCBCR_BT2020)))
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & (BIT(DRM_COLOR_YCBCR_BT601) |
+		    BIT(DRM_COLOR_YCBCR_BT709) |
+		    BIT(DRM_COLOR_YCBCR_BT2020))) == 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		/* Ensures that the default rotation is included in supported rotation */
+		if (plane->dev->enabled)
+			return -EINVAL;
+
+		vkms_config_plane_set_default_color_encoding(plane->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
 CONFIGFS_ATTR(plane_, supported_rotations);
 CONFIGFS_ATTR(plane_, default_rotation);
+CONFIGFS_ATTR(plane_, supported_color_encodings);
+CONFIGFS_ATTR(plane_, default_color_encoding);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
 	&plane_attr_name,
 	&plane_attr_supported_rotations,
 	&plane_attr_default_rotation,
+	&plane_attr_supported_color_encodings,
+	&plane_attr_default_color_encoding,
 	NULL,
 };
 

-- 
2.51.0