[v2 2/2] drm/i915/icl: Enable Plane Input CSC for YUV to RGB Conversion

[Uma Shankar <uma.shankar@intel.com>]

Plane input CSC needs to be enabled to convert frambuffers from
YUV to RGB. This is needed for bottom 3 planes on ICL, rest of
the planes have hardcoded conversion and taken care by the legacy
code.

This patch defines the co-efficient values for YUV to RGB conversion
in BT709 and BT601 formats. It programs the coefficients and enables
the plane input csc unit in hardware.

Note: This is currently untested and floated to get an early feedback
on the design and implementation for this feature. In parallel,
I will test this on actual ICL hardware and confirm with planar
formats.

v2: Addressed Maarten's and Ville's review comments and added the
coefficients in a 2D array instead of independent Macros.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/intel_color.c   | 49 ++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_display.c | 24 +++++++++++++-----
 drivers/gpu/drm/i915/intel_drv.h     |  2 ++
 3 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_color.c b/drivers/gpu/drm/i915/intel_color.c
index 5127da2..de733cf 100644
--- a/drivers/gpu/drm/i915/intel_color.c
+++ b/drivers/gpu/drm/i915/intel_color.c
@@ -57,6 +57,11 @@
 #define CSC_RGB_TO_YUV_RV_GV 0xbce89ad8
 #define CSC_RGB_TO_YUV_BV 0x1e080000
 
+/* Preoffset values for YUV to RGB Conversion */
+#define PREOFF_YUV_TO_RGB_HI		0x800
+#define PREOFF_YUV_TO_RGB_ME		0xF00
+#define PREOFF_YUV_TO_RGB_LO		0x800
+
 /*
  * Extract the CSC coefficient from a CTM coefficient (in U32.32 fixed point
  * format). This macro takes the coefficient we want transformed and the
@@ -643,6 +648,50 @@ int intel_color_check(struct drm_crtc *crtc,
 	return -EINVAL;
 }
 
+void icl_program_input_csc_coeff(const struct intel_crtc_state *crtc_state,
+				 const struct intel_plane_state *plane_state)
+{
+	struct drm_i915_private *dev_priv =
+		to_i915(plane_state->base.plane->dev);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
+	enum pipe pipe = crtc->pipe;
+	struct intel_plane *intel_plane =
+		to_intel_plane(plane_state->base.plane);
+	enum plane_id plane = intel_plane->id;
+
+	static const u32 input_csc_matrix[][6] = {
+		/* BT.601 full range YCbCr -> full range RGB */
+		[DRM_COLOR_YCBCR_BT601] = {
+			0x7AF87800, 0x0, 0x8B287800,
+			0x9AC0, 0x7800, 0x7DD8,
+		},
+		/* BT.709 full range YCbCr -> full range RGB */
+		[DRM_COLOR_YCBCR_BT709] = {
+			0x7C987800, 0x0, 0x9EF87800,
+			0xABF8, 0x7800,  0x7ED8,
+		},
+	};
+	const u32 *csc = input_csc_matrix[plane_state->base.color_encoding];
+
+	I915_WRITE(PLANE_INPUT_CSC_RY_GY(pipe, plane), csc[0]);
+	I915_WRITE(PLANE_INPUT_CSC_BY(pipe, plane), csc[1]);
+	I915_WRITE(PLANE_INPUT_CSC_RU_GU(pipe, plane), csc[2]);
+	I915_WRITE(PLANE_INPUT_CSC_BU(pipe, plane), csc[3]);
+	I915_WRITE(PLANE_INPUT_CSC_RV_GV(pipe, plane), csc[4]);
+	I915_WRITE(PLANE_INPUT_CSC_BV(pipe, plane), csc[5]);
+
+	I915_WRITE(PLANE_INPUT_CSC_PREOFF_HI(pipe, plane),
+		   PREOFF_YUV_TO_RGB_HI);
+	I915_WRITE(PLANE_INPUT_CSC_PREOFF_ME(pipe, plane),
+		   PREOFF_YUV_TO_RGB_ME);
+	I915_WRITE(PLANE_INPUT_CSC_PREOFF_LO(pipe, plane),
+		   PREOFF_YUV_TO_RGB_LO);
+
+	I915_WRITE(PLANE_INPUT_CSC_POSTOFF_HI(pipe, plane), 0x0);
+	I915_WRITE(PLANE_INPUT_CSC_POSTOFF_ME(pipe, plane), 0x0);
+	I915_WRITE(PLANE_INPUT_CSC_POSTOFF_LO(pipe, plane), 0x0);
+}
+
 void intel_color_init(struct drm_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fe045ab..be65419 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3666,6 +3666,8 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state *crtc_state,
 	struct drm_i915_private *dev_priv =
 		to_i915(plane_state->base.plane->dev);
 	const struct drm_framebuffer *fb = plane_state->base.fb;
+	struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
+
 	u32 plane_color_ctl = 0;
 
 	if (INTEL_GEN(dev_priv) < 11) {
@@ -3676,13 +3678,23 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state *crtc_state,
 	plane_color_ctl |= glk_plane_color_ctl_alpha(plane_state);
 
 	if (fb->format->is_yuv) {
-		if (plane_state->base.color_encoding == DRM_COLOR_YCBCR_BT709)
-			plane_color_ctl |= PLANE_COLOR_CSC_MODE_YUV709_TO_RGB709;
-		else
-			plane_color_ctl |= PLANE_COLOR_CSC_MODE_YUV601_TO_RGB709;
+		if (!icl_is_hdr_plane(plane)) {
+			if (plane_state->base.color_encoding ==
+					DRM_COLOR_YCBCR_BT709)
+				plane_color_ctl |=
+					PLANE_COLOR_CSC_MODE_YUV709_TO_RGB709;
+			else
+				plane_color_ctl |=
+					PLANE_COLOR_CSC_MODE_YUV601_TO_RGB709;
 
-		if (plane_state->base.color_range == DRM_COLOR_YCBCR_FULL_RANGE)
-			plane_color_ctl |= PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE;
+			if (plane_state->base.color_range ==
+					DRM_COLOR_YCBCR_FULL_RANGE)
+				plane_color_ctl |=
+				PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE;
+		} else {
+			icl_program_input_csc_coeff(crtc_state, plane_state);
+			plane_color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE;
+		}
 	}
 
 	return plane_color_ctl;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index db24308..bd9e946 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -2285,6 +2285,8 @@ int intel_plane_atomic_check_with_state(const struct intel_crtc_state *old_crtc_
 int intel_color_check(struct drm_crtc *crtc, struct drm_crtc_state *state);
 void intel_color_set_csc(struct drm_crtc_state *crtc_state);
 void intel_color_load_luts(struct drm_crtc_state *crtc_state);
+void icl_program_input_csc_coeff(const struct intel_crtc_state *crtc_state,
+				 const struct intel_plane_state *plane_state);
 
 /* intel_lspcon.c */
 bool lspcon_init(struct intel_digital_port *intel_dig_port);
-- 
1.9.1

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