[PATCH RFC 5/7] drm/vkms: Add color encoding to ConfigFS

[Louis Chauvet]

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`.

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

Signed-off-by: Louis Chauvet <louis.chauvet at bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_configfs.c | 107 +++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index d121cf54e752..a3dab5986882 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -152,14 +152,121 @@ static ssize_t plane_default_rotation_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_color_encoding_show(struct config_item *item, char *page)
+{
+	struct vkms_config_plane *plane;
+	unsigned int supported_color_encoding;
+	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;
+	supported_color_encoding = plane->supported_color_encoding;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return sprintf(page, "%u", supported_color_encoding);
+}
+
+static ssize_t plane_supported_color_encoding_store(struct config_item *item,
+						    const char *page, size_t count)
+{
+	struct vkms_configfs_device *vkms_configfs = plane_item_to_vkms_configfs_device(item);
+	struct vkms_config_plane *plane;
+	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;
+
+	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_color_encoding) !=
+				      plane->default_color_encoding) {
+		mutex_unlock(&vkms_configfs->lock);
+		return -EINVAL;
+	}
+	plane->supported_color_encoding = val;
+	mutex_unlock(&vkms_configfs->lock);
+
+	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_config_plane *plane;
+	unsigned int default_color_encoding;
+	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;
+	default_color_encoding = plane->default_color_encoding;
+	mutex_unlock(&vkms_configfs->lock);
+
+	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_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 & ~(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;
+	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_color_encoding) != val) {
+		mutex_unlock(&vkms_configfs->lock);
+		return -EINVAL;
+	}
+	plane->default_color_encoding = val;
+	mutex_unlock(&vkms_configfs->lock);
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, supported_rotations);
 CONFIGFS_ATTR(plane_, default_rotation);
+CONFIGFS_ATTR(plane_, supported_color_encoding);
+CONFIGFS_ATTR(plane_, default_color_encoding);
 
 static struct configfs_attribute *plane_attrs[] = {
 	&plane_attr_type,
 	&plane_attr_supported_rotations,
 	&plane_attr_default_rotation,
+	&plane_attr_supported_color_encoding,
+	&plane_attr_default_color_encoding,
 	NULL,
 };
 

-- 
2.44.2