[Intel-gfx] [PATCH v7 6/7] drm/framebuffer/tgl: Format modifier for Intel Gen 12 render compression with Clear Color

[Radhakrishna Sripada]

Gen12 display can decompress surfaces compressed by render engine with
Clear Color, add a new modifier as the driver needs to know the surface
was compressed by render engine.

V2: Description changes as suggested by Rafael.
V3: Mention the Clear Color size of 64 bits in the comments(DK)
v4: Fix trailing whitespaces
v5: Explain Clear Color in the documentation.
v6: Documentation Nitpicks(Nanley)
v7: Remove ambiguity in Clear Color structue explanation(Nanley)

Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Cc: Kalyan Kondapally <kalyan.kondapally at intel.com>
Cc: Rafael Antognolli <rafael.antognolli at intel.com>
Reviewed-by: Nanley Chery <nanley.g.chery at intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
---
 include/uapi/drm/drm_fourcc.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index 5ba481f49931..c95dd3c40636 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -421,6 +421,25 @@ extern "C" {
  */
 #define I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS fourcc_mod_code(INTEL, 6)
 
+/*
+ * Intel Color Control Surface with Clear Color (CCS) for Gen-12 render
+ * compression.
+ *
+ * The main surface is Y-tiled and is at plane index 0 whereas CCS is linear
+ * and at index 1. The clear color is stored at index 2, and the pitch should
+ * be ignored. The clear color structure is 256 bits. The first 128 bits
+ * represents Raw Clear Color Red, Green, Blue and Alpha color each represented
+ * by 32 bits. The 3D engine can use the raw clear color and the surface format
+ * to generate a converted clear color of size 64 bits. The first 32 bits store
+ * the Lower Converted Clear Color value and the next 32 bits store the Higher
+ * Converted Clear Color value when applicable. The Converted Clear Color values
+ * are consumed by the DE. The last 64 bits are used to store Color Discard
+ * Enable and Depth Clear Value Valid which are ignored by the DE. A CCS cache
+ * line corresponds to an area of 4x1 tiles in the main surface. The main
+ * surface pitch is required to be a multiple of 4 tile widths.
+ */
+#define I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS_CC fourcc_mod_code(INTEL, 8)
+
 /*
  * Tiled, NV12MT, grouped in 64 (pixels) x 32 (lines) -sized macroblocks
  *
-- 
2.20.1