[PATCH v6 15/23] drm/i915: CHV: Pipe level CSC correction

[Shashank Sharma <shashank.sharma@intel.com>]

CHV/BSW supports Color Space Conversion (CSC) using a 3x3 matrix
that needs to be programmed into CGM (Color Gamut Mapping) registers.

This patch does the following:
1. Attaches CSC property to CRTC
2. Adds the core function to program CSC correction values
3. Adds CSC correction macros

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kausal Malladi <kausalmalladi@gmail.com>
Signed-off-by: Kumar, Kiran S <kiran.s.kumar@intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h            |  8 +++
 drivers/gpu/drm/i915/intel_color_manager.c | 99 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_color_manager.h | 19 ++++++
 3 files changed, 126 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 1e46562..3db42f4 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8166,4 +8166,12 @@ enum skl_disp_power_wells {
 #define _PIPE_DEGAMMA_BASE(pipe) \
 	(_PIPE3(pipe, PIPEA_CGM_DEGAMMA, PIPEB_CGM_DEGAMMA, PIPEC_CGM_DEGAMMA))
 
+#define PIPEA_CGM_CSC				(VLV_DISPLAY_BASE + 0x67900)
+#define PIPEB_CGM_CSC				(VLV_DISPLAY_BASE + 0x69900)
+#define PIPEC_CGM_CSC				(VLV_DISPLAY_BASE + 0x6B900)
+#define _PIPE_CSC_BASE(pipe) \
+	(_PIPE3(pipe, PIPEA_CGM_CSC, PIPEB_CGM_CSC, PIPEC_CGM_CSC))
+
+
+
 #endif /* _I915_REG_H_ */
diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
index 1bbad79..6661c53 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.c
+++ b/drivers/gpu/drm/i915/intel_color_manager.c
@@ -27,6 +27,98 @@
 
 #include "intel_color_manager.h"
 
+static s32 chv_prepare_csc_coeff(s64 csc_value)
+{
+	s32 csc_int_value;
+	u32 csc_fract_value;
+	s32 csc_s3_12_format;
+
+	if (csc_value >= 0) {
+		csc_value += CHV_CSC_FRACT_ROUNDOFF;
+		if (csc_value > CHV_CSC_COEFF_MAX)
+			csc_value = CHV_CSC_COEFF_MAX;
+	} else {
+		csc_value = -csc_value;
+		csc_value += CHV_CSC_FRACT_ROUNDOFF;
+		if (csc_value > CHV_CSC_COEFF_MAX + 1)
+			csc_value = CHV_CSC_COEFF_MAX + 1;
+		csc_value = -csc_value;
+	}
+
+	csc_int_value = csc_value >> CHV_CSC_COEFF_SHIFT;
+	csc_int_value <<= CHV_CSC_COEFF_INT_SHIFT;
+	if (csc_value < 0)
+		csc_int_value |= CSC_COEFF_SIGN;
+
+	csc_fract_value = csc_value;
+	csc_fract_value >>= CHV_CSC_COEFF_FRACT_SHIFT;
+	csc_s3_12_format = csc_int_value | csc_fract_value;
+
+	return csc_s3_12_format;
+}
+
+static int chv_set_csc(struct drm_device *dev, struct drm_property_blob *blob,
+		struct drm_crtc *crtc)
+{
+	struct drm_ctm *csc_data;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg;
+	enum pipe pipe;
+	s32 word = 0, temp;
+	int count = 0;
+
+	if (WARN_ON(!blob))
+		return -EINVAL;
+
+	if (blob->length != sizeof(struct drm_ctm)) {
+		DRM_ERROR("Invalid length of data received\n");
+		return -EINVAL;
+	}
+
+	csc_data = (struct drm_ctm *)blob->data;
+	pipe = to_intel_crtc(crtc)->pipe;
+
+	/* Disable CSC functionality */
+	reg = _PIPE_CGM_CONTROL(pipe);
+	I915_WRITE(reg, I915_READ(reg) & (~CGM_CSC_EN));
+
+	DRM_DEBUG_DRIVER("Disabled CSC Functionality on Pipe %c\n",
+			pipe_name(pipe));
+
+	reg = _PIPE_CSC_BASE(pipe);
+
+	/*
+	* First 8 of 9 CSC correction values go in pair, to first
+	* 4 CSC register (bit 0:15 and 16:31)
+	*/
+	while (count < CSC_MAX_VALS - 1) {
+		temp = chv_prepare_csc_coeff(
+					csc_data->ctm_coeff[count]);
+		SET_BITS(word, GET_BITS(temp, 16, 16), 0, 16);
+		count++;
+
+		temp = chv_prepare_csc_coeff(
+				csc_data->ctm_coeff[count]);
+		SET_BITS(word, GET_BITS(temp, 16, 16), 16, 16);
+		count++;
+
+		I915_WRITE(reg, word);
+		reg += 4;
+	}
+
+	/* 9th coeff goes to 5th register, bit 0:16 */
+	temp = chv_prepare_csc_coeff(
+			csc_data->ctm_coeff[count]);
+	SET_BITS(word, GET_BITS(temp, 16, 16), 0, 16);
+	I915_WRITE(reg, word);
+
+	/* Enable CSC functionality */
+	reg = _PIPE_CGM_CONTROL(pipe);
+	I915_WRITE(reg, I915_READ(reg) | CGM_CSC_EN);
+	DRM_DEBUG_DRIVER("CSC enabled on Pipe %c\n", pipe_name(pipe));
+	return 0;
+}
+
 static int chv_set_degamma(struct drm_device *dev,
 	struct drm_property_blob *blob, struct drm_crtc *crtc)
 {
@@ -247,4 +339,11 @@ void intel_attach_color_properties_to_crtc(struct drm_device *dev,
 			config->cm_palette_before_ctm_property, 0);
 		DRM_DEBUG_DRIVER("degamma property attached to CRTC\n");
 	}
+
+	/* CSC */
+	if (config->cm_ctm_property) {
+		drm_object_attach_property(mode_obj,
+			config->cm_ctm_property, 0);
+		DRM_DEBUG_DRIVER("CSC property attached to CRTC\n");
+	}
 }
diff --git a/drivers/gpu/drm/i915/intel_color_manager.h b/drivers/gpu/drm/i915/intel_color_manager.h
index 77a2119..7b96512 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.h
+++ b/drivers/gpu/drm/i915/intel_color_manager.h
@@ -63,10 +63,29 @@
 #define CHV_GAMMA_SHIFT_GREEN                  16
 #define CHV_MAX_GAMMA                          ((1 << 24) - 1)
 
+/*
+ * CSC on CHV
+ * Fractional part is 32 bit, and we need only 12 MSBs for programming
+ * into registers. ROUNDOFF is required to minimize loss of precision.
+ */
+#define CHV_CSC_FRACT_ROUNDOFF                 (1 << 19)
+/*
+ * CSC values are 64-bit values. For CHV, the maximum CSC value that
+ * user can program is 7.99999..., which can be represented in fixed point
+ * S31.32 format like this, with all fractional bits as 1
+ */
+#define CHV_CSC_COEFF_MAX                      0x00000007FFFFFFFF
+#define CHV_CSC_COEFF_SHIFT                    32
+#define CHV_CSC_COEFF_INT_SHIFT                28
+#define CSC_COEFF_SIGN                         (1 << 31)
+#define CHV_CSC_COEFF_FRACT_SHIFT              4
+#define CSC_MAX_VALS                           9
+
 /* Degamma on CHV */
 #define CHV_DEGAMMA_MSB_SHIFT                  2
 #define CHV_DEGAMMA_GREEN_SHIFT                16
 
 /* CHV CGM Block */
 #define CGM_GAMMA_EN                           (1 << 2)
+#define CGM_CSC_EN                             (1 << 1)
 #define CGM_DEGAMMA_EN                         (1 << 0)
-- 
1.9.1

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