[PATCH 13/22] drm/i915: CHV: Pipe level Gamma correction

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

CHV/BSW platform supports two different pipe level gamma
correction modes, which are:
1. Legacy 8-bit mode
2. 10-bit CGM (Color Gamut Mapping) mode

This patch does the following:
1. Attaches Gamma property to CRTC
3. Adds the core Gamma correction function for CHV/BSW
4. Adds Gamma correction macros

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kausal Malladi <kausalmalladi@gmail.com>
---
 drivers/gpu/drm/i915/i915_reg.h            |  12 +++
 drivers/gpu/drm/i915/intel_color_manager.c | 114 +++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_color_manager.h |  13 ++++
 3 files changed, 139 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 60e6a73..885ac8a 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8038,4 +8038,16 @@ enum skl_disp_power_wells {
 #define GEN9_VEBOX_MOCS_0	0xcb00	/* Video MOCS base register*/
 #define GEN9_BLT_MOCS_0		0xcc00	/* Blitter MOCS base register*/
 
+/* Color Management */
+#define PIPEA_CGM_CONTROL			(VLV_DISPLAY_BASE + 0x67A00)
+#define PIPEB_CGM_CONTROL			(VLV_DISPLAY_BASE + 0x69A00)
+#define PIPEC_CGM_CONTROL			(VLV_DISPLAY_BASE + 0x6BA00)
+#define PIPEA_CGM_GAMMA			(VLV_DISPLAY_BASE + 0x67000)
+#define PIPEB_CGM_GAMMA			(VLV_DISPLAY_BASE + 0x69000)
+#define PIPEC_CGM_GAMMA			(VLV_DISPLAY_BASE + 0x6B000)
+#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))
+
 #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 e466748..cf381b8 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.c
+++ b/drivers/gpu/drm/i915/intel_color_manager.c
@@ -27,6 +27,112 @@
 
 #include "intel_color_manager.h"
 
+static int chv_set_gamma(struct drm_device *dev, struct drm_property_blob *blob,
+		struct drm_crtc *crtc)
+{
+	bool flag = false;
+	enum pipe pipe;
+	u16 red_fract, green_fract, blue_fract;
+	u32 red, green, blue, num_samples;
+	u32 word = 0;
+	u32 count = 0;
+	u32 cgm_gamma_reg = 0;
+	u32 cgm_control_reg = 0;
+	int ret = 0, length;
+	struct drm_r32g32b32 *correction_values = NULL;
+	struct drm_palette *gamma_data;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (WARN_ON(!blob))
+		return -EINVAL;
+
+	gamma_data = (struct drm_palette *)blob->data;
+	pipe = to_intel_crtc(crtc)->pipe;
+	num_samples = gamma_data->num_samples;
+	length = num_samples * sizeof(struct drm_r32g32b32);
+
+	switch (num_samples) {
+	case GAMMA_DISABLE_VALS:
+
+		/* Disable Gamma functionality on Pipe - CGM Block */
+		cgm_control_reg = I915_READ(_PIPE_CGM_CONTROL(pipe));
+		cgm_control_reg &= ~CGM_GAMMA_EN;
+		I915_WRITE(_PIPE_CGM_CONTROL(pipe), cgm_control_reg);
+
+		DRM_DEBUG_DRIVER("Gamma disabled on Pipe %c\n",
+		pipe_name(pipe));
+		ret = 0;
+		break;
+
+	case CHV_8BIT_GAMMA_MAX_VALS:
+	case CHV_10BIT_GAMMA_MAX_VALS:
+
+		count = 0;
+		cgm_gamma_reg = _PIPE_GAMMA_BASE(pipe);
+		correction_values = (struct drm_r32g32b32 *)&gamma_data->lut;
+
+		while (count < num_samples) {
+			blue = correction_values[count].b32;
+			green = correction_values[count].g32;
+			red = correction_values[count].r32;
+
+			if (blue > CHV_MAX_GAMMA)
+				blue = CHV_MAX_GAMMA;
+
+			if (green > CHV_MAX_GAMMA)
+				green = CHV_MAX_GAMMA;
+
+			if (red > CHV_MAX_GAMMA)
+				red = CHV_MAX_GAMMA;
+
+			/* get MSB 10 bits from fraction part (14:23) */
+			blue_fract = GET_BITS(blue, 14, 10);
+			green_fract = GET_BITS(green, 14, 10);
+			red_fract = GET_BITS(red, 14, 10);
+
+			/* Green (25:16) and Blue (9:0) to be written */
+			SET_BITS(word, green_fract, 16, 10);
+			SET_BITS(word, blue_fract, 0, 10);
+			I915_WRITE(cgm_gamma_reg, word);
+			cgm_gamma_reg += 4;
+
+			/* Red (9:0) to be written */
+			word = red_fract;
+			I915_WRITE(cgm_gamma_reg, word);
+
+			cgm_gamma_reg += 4;
+			count++;
+
+			/*
+			* On CHV, the best supported Gamma capability is
+			* CGM block, that takes 257 samples.
+			* If user gives 256 samples (legacy mode), then
+			* duplicate the 256th value to 257th.
+			* "flag" is used to make sure it happens only once
+			*/
+			if (num_samples == CHV_8BIT_GAMMA_MAX_VALS &&
+				count == CHV_8BIT_GAMMA_MAX_VALS && !flag) {
+				count--;
+				flag = true;
+			}
+		}
+
+		/* Enable (CGM) Gamma on Pipe */
+		I915_WRITE(_PIPE_CGM_CONTROL(pipe),
+		I915_READ(_PIPE_CGM_CONTROL(pipe)) | CGM_GAMMA_EN);
+		DRM_DEBUG_DRIVER("CGM Gamma enabled on Pipe %c\n",
+		pipe_name(pipe));
+		ret = 0;
+		break;
+
+	default:
+		DRM_ERROR("Invalid number of samples for Gamma LUT\n");
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 void intel_attach_color_properties_to_crtc(struct drm_device *dev,
 		struct drm_crtc *crtc)
 {
@@ -61,4 +167,12 @@ void intel_attach_color_properties_to_crtc(struct drm_device *dev,
 				INTEL_INFO(dev)->num_samples_before_ctm);
 		DRM_DEBUG_DRIVER("Degamma query property initialized\n");
 	}
+
+	/* Gamma correction */
+	if (config->cm_palette_after_ctm_property) {
+		drm_object_attach_property(mode_obj,
+			config->cm_palette_after_ctm_property, 0);
+		DRM_DEBUG_DRIVER("gamma 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 14a1309..de706d9 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.h
+++ b/drivers/gpu/drm/i915/intel_color_manager.h
@@ -52,3 +52,16 @@
 /* CHV */
 #define CHV_10BIT_GAMMA_MAX_VALS		257
 #define CHV_DEGAMMA_MAX_VALS                   65
+
+/* No of coeff for disabling gamma is 0 */
+#define GAMMA_DISABLE_VALS			0
+
+/* Gamma on CHV */
+#define CHV_10BIT_GAMMA_MAX_VALS               257
+#define CHV_8BIT_GAMMA_MAX_VALS                256
+#define CHV_10BIT_GAMMA_MSB_SHIFT              6
+#define CHV_GAMMA_SHIFT_GREEN                  16
+#define CHV_MAX_GAMMA                          ((1 << 24) - 1)
+
+/* CHV CGM Block */
+#define CGM_GAMMA_EN                           (1 << 2)
-- 
1.9.1

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