lib/igt_fb: Add a helper to retreive the plane bpp for a given format

The format bpp for a given plane is stored in the static format_desc
structure and is not accessible to tests, which is inconvenient to
get the minimum stride for a format when testing various strides.

Add a simple helper to expose the information.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Maxime Ripard <maxime.ripard@bootlin.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/igt_fb.c b/lib/igt_fb.c
index f1989249..48f7921e 100644
--- a/lib/igt_fb.c
+++ b/lib/igt_fb.c
@@ -2727,3 +2727,19 @@ bool igt_format_is_yuv(uint32_t drm_format)
 		return false;
 	}
 }
+
+/**
+ * igt_format_plane_bpp:
+ * @drm_format: drm fourcc
+ * @plane: format plane index
+ *
+ * This functions returns the number of bits per pixel for the given @plane
+ * index of the @drm_format.
+ */
+int igt_format_plane_bpp(uint32_t drm_format, int plane)
+{
+	const struct format_desc_struct *format =
+		lookup_drm_format(drm_format);
+
+	return format->plane_bpp[plane];
+}