[PATCH 16/16] drm/i915: Add CSC correction for CHV/BSW

[Kausal Malladi <Kausal.Malladi@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. Adds the core function to program CSC correction values for
   CHV/BSW platform
2. Adds CSC correction macros/defines

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kausal Malladi <Kausal.Malladi@intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h            |   5 ++
 drivers/gpu/drm/i915/intel_color_manager.c | 110 +++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_color_manager.h |  20 ++++++
 3 files changed, 135 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index b95862e..9bf5720 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7916,11 +7916,16 @@ enum skl_disp_power_wells {
 #define PIPEA_CGM_DEGAMMA			(VLV_DISPLAY_BASE + 0x66000)
 #define PIPEB_CGM_DEGAMMA			(VLV_DISPLAY_BASE + 0x68000)
 #define PIPEC_CGM_DEGAMMA			(VLV_DISPLAY_BASE + 0x6A000)
+#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_CGM_CONTROL(pipe) \
 	(_PIPE3(pipe, PIPEA_CGM_CONTROL, PIPEB_CGM_CONTROL, PIPEC_CGM_CONTROL))
 #define _PIPE_GAMMA_BASE(pipe) \
 	(_PIPE3(pipe, PIPEA_CGM_GAMMA, PIPEB_CGM_GAMMA, PIPEC_CGM_GAMMA))
 #define _PIPE_DEGAMMA_BASE(pipe) \
 	(_PIPE3(pipe, PIPEA_CGM_DEGAMMA, PIPEB_CGM_DEGAMMA, PIPEC_CGM_DEGAMMA))
+#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 bd60fad..e855d5d 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.c
+++ b/drivers/gpu/drm/i915/intel_color_manager.c
@@ -27,6 +27,108 @@
 
 #include "intel_color_manager.h"
 
+s16 get_csc_s3_12_format(s64 csc_value)
+{
+	s32 csc_int_value;
+	u32 csc_fract_value;
+	s16 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;
+}
+
+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;
+	struct drm_mode_config *config = &dev->mode_config;
+	u32 reg;
+	enum pipe pipe;
+	s32 word, temp;
+	int ret, count = 0;
+
+	if (!blob) {
+		DRM_ERROR("NULL Blob\n");
+		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;
+	if (csc_data->version != CHV_CSC_DATA_STRUCT_VERSION) {
+		DRM_ERROR("Invalid CSC Data struct version\n");
+		return -EINVAL;
+	}
+
+	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);
+	while (count < CSC_MAX_VALS) {
+		word = get_csc_s3_12_format(csc_data->ctm_coeff[count]);
+
+		/*
+		 * Last value to be written in 1 register.
+		 * Otherwise, each pair of CSC values go
+		 * into 1 register
+		 */
+		if (count != (CSC_MAX_VALS - 1)) {
+			count++;
+			temp = get_csc_s3_12_format(csc_data->ctm_coeff[count]);
+			word |= temp;
+		}
+		I915_WRITE(reg, word);
+		reg += 4;
+		count++;
+	}
+
+	DRM_DEBUG_DRIVER("All CSC values written to registers\n");
+
+	/* 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));
+
+	ret = drm_property_replace_global_blob(dev, &blob,
+			sizeof(struct drm_ctm), (void *) csc_data,
+			&crtc->base, config->prop_ctm);
+	if (ret) {
+		DRM_ERROR("Error updating CSC blob\n");
+		return -EFAULT;
+	}
+
+	return ret;
+}
+
 int chv_set_degamma(struct drm_device *dev, struct drm_property_blob *blob,
 		struct drm_crtc *crtc)
 {
@@ -295,6 +397,14 @@ void intel_color_manager_crtc_commit(struct drm_device *dev,
 				DRM_DEBUG_DRIVER(
 					"DeGamma registers Commit success!\n");
 		}
+
+		blob = crtc_state->ctm_blob;
+		if (blob) {
+			ret = chv_set_csc(dev, blob, crtc);
+			if (!ret)
+				DRM_DEBUG_DRIVER(
+					"CSC registers Commit success!\n");
+		}
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/intel_color_manager.h b/drivers/gpu/drm/i915/intel_color_manager.h
index 6a4fff2..b2ee847 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.h
+++ b/drivers/gpu/drm/i915/intel_color_manager.h
@@ -54,6 +54,26 @@
 #define CHV_DEGAMMA_MSB_SHIFT			2
 #define CHV_DEGAMMA_GREEN_SHIFT			16
 
+/* CSC correction */
+#define CHV_CSC_DATA_STRUCT_VERSION		1
+/*
+ * 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		20
+#define CSC_MAX_VALS				9
+
 /* CHV CGM Block */
 #define CGM_GAMMA_EN				(1 << 2)
+#define CGM_CSC_EN				(1 << 1)
 #define CGM_DEGAMMA_EN				(1 << 0)
-- 
2.4.5

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