[PATCH 9/9] drm/i915/xelpd: Enable XE_LPD Gamma Lut readout

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

Enable support for Logarithmic gamma readout for XE_LPD.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/display/intel_color.c | 72 ++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h            |  6 ++
 2 files changed, 78 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index a8b771f22880..1238fe05b358 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -486,6 +486,17 @@ static void icl_lut_multi_seg_pack(struct drm_color_lut *entry, u32 ldw, u32 udw
 				    REG_FIELD_GET(PAL_PREC_MULTI_SEG_BLUE_LDW_MASK, ldw);
 }
 
+static void d13_lut_logarithmic_pack(struct drm_color_lut *entry,
+				     u32 ldw, u32 udw)
+{
+	entry->red = REG_FIELD_GET(PAL_PREC_LOGARITHMIC_RED_UDW_MASK, udw) << 6 |
+				   REG_FIELD_GET(PAL_PREC_LOGARITHMIC_RED_LDW_MASK, ldw);
+	entry->green = REG_FIELD_GET(PAL_PREC_LOGARITHMIC_GREEN_UDW_MASK, udw) << 6 |
+				     REG_FIELD_GET(PAL_PREC_LOGARITHMIC_GREEN_LDW_MASK, ldw);
+	entry->blue = REG_FIELD_GET(PAL_PREC_LOGARITHMIC_BLUE_UDW_MASK, udw) << 6 |
+				    REG_FIELD_GET(PAL_PREC_LOGARITHMIC_BLUE_LDW_MASK, ldw);
+}
+
 static void i9xx_color_commit(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
@@ -2434,6 +2445,66 @@ static void d13_load_luts(const struct intel_crtc_state *crtc_state)
 	intel_dsb_commit(crtc_state);
 }
 
+static struct drm_property_blob *
+d13_read_lut_logarithmic(struct intel_crtc *crtc)
+{
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	int i, lut_size = INTEL_INFO(dev_priv)->color.gamma_lut_size;
+	enum pipe pipe = crtc->pipe;
+	struct drm_property_blob *blob;
+	struct drm_color_lut *lut;
+	u32 gamma_max_val = 0xFFFF;
+
+	blob = drm_property_create_blob(&dev_priv->drm,
+					sizeof(struct drm_color_lut) * lut_size,
+					NULL);
+	if (IS_ERR(blob))
+		return NULL;
+
+	lut = blob->data;
+
+	intel_de_write(dev_priv, PREC_PAL_INDEX(pipe),
+		       PAL_PREC_AUTO_INCREMENT);
+
+	for (i = 0; i < lut_size - 3; i++) {
+		u32 ldw = intel_de_read(dev_priv, PREC_PAL_DATA(pipe));
+		u32 udw = intel_de_read(dev_priv, PREC_PAL_DATA(pipe));
+
+		d13_lut_logarithmic_pack(&lut[i], ldw, udw);
+	}
+
+	/* All the extended ranges are now limited to last value of 1.0 */
+	while (i < lut_size) {
+		lut[i].red = gamma_max_val;
+		lut[i].green = gamma_max_val;
+		lut[i].blue = gamma_max_val;
+		i++;
+	};
+
+	intel_de_write(dev_priv, PREC_PAL_INDEX(pipe), 0);
+
+	return blob;
+}
+
+static void d13_read_luts(struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+
+	if ((crtc_state->gamma_mode & POST_CSC_GAMMA_ENABLE) == 0)
+		return;
+
+	switch (crtc_state->gamma_mode & GAMMA_MODE_MODE_MASK) {
+	case GAMMA_MODE_MODE_8BIT:
+		crtc_state->hw.gamma_lut = ilk_read_lut_8(crtc);
+		break;
+	case GAMMA_MODE_MODE_12BIT_LOGARITHMIC:
+		crtc_state->hw.gamma_lut = d13_read_lut_logarithmic(crtc);
+		break;
+	default:
+		crtc_state->hw.gamma_lut = bdw_read_lut_10(crtc, PAL_PREC_INDEX_VALUE(0));
+	}
+}
+
 void intel_color_init(struct intel_crtc *crtc)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
@@ -2488,6 +2559,7 @@ void intel_color_init(struct intel_crtc *crtc)
 
 		if (DISPLAY_VER(dev_priv) >= 13) {
 			dev_priv->display.load_luts = d13_load_luts;
+			dev_priv->display.read_luts = d13_read_luts;
 		} else if (DISPLAY_VER(dev_priv) >= 11) {
 			dev_priv->display.load_luts = icl_load_luts;
 			dev_priv->display.read_luts = icl_read_luts;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 957f97edf035..dc10b5e2ff3c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7750,6 +7750,12 @@ enum {
 #define  GAMMA_MODE_MODE_SPLIT	(3 << 0) /* ivb-bdw */
 #define  GAMMA_MODE_MODE_12BIT_MULTI_SEGMENTED	(3 << 0) /* icl + */
 #define  GAMMA_MODE_MODE_12BIT_LOGARITHMIC	(3 << 0) /* D13+ + */
+#define  PAL_PREC_LOGARITHMIC_RED_LDW_MASK	REG_GENMASK(29, 24)
+#define  PAL_PREC_LOGARITHMIC_RED_UDW_MASK	REG_GENMASK(29, 20)
+#define  PAL_PREC_LOGARITHMIC_GREEN_LDW_MASK	REG_GENMASK(19, 14)
+#define  PAL_PREC_LOGARITHMIC_GREEN_UDW_MASK	REG_GENMASK(19, 10)
+#define  PAL_PREC_LOGARITHMIC_BLUE_LDW_MASK	REG_GENMASK(9, 4)
+#define  PAL_PREC_LOGARITHMIC_BLUE_UDW_MASK	REG_GENMASK(9, 0)
 
 /* DMC */
 #define DMC_PROGRAM(i)		_MMIO(0x80000 + (i) * 4)
-- 
2.26.2