[PATCH 17/18] drm/i915: Add DeGamma correction for BDW/SKL/BXT

Shashank Sharma
2015-08-06T16:38:26Z

From: Kausal Malladi <kausalmalladi@gmail.com>

BDW/SKL/BXT supports DeGamma color correction feature, which linearizes all
the non-linear color values. This will be applied before Color
Transformation.

This patch does the following:
1. Adds the core function to program DeGamma correction values for
BDW/SKL/BXT platform
2. Adds DeGamma correction macros/defines

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Kausal Malladi <kausalmalladi@gmail.com>
---
drivers/gpu/drm/i915/intel_color_manager.c | 68 ++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_color_manager.h | 2 +
2 files changed, 70 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
index a894f4c..9f9fb1a 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.c
+++ b/drivers/gpu/drm/i915/intel_color_manager.c
@@ -154,6 +154,72 @@ u32 gen9_write_10bit_gamma_precision(u32 red, u32 green, u32 blue)
return word;
}

+int gen9_set_degamma(struct drm_device *dev, struct drm_property_blob *blob,
+ struct drm_crtc *crtc)
+{
+ struct drm_palette *degamma_data;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct drm_r32g32b32 *correction_values = NULL;
+ u32 mode, pal_prec_index, pal_prec_data;
+ int count = 0;
+ u32 blue, green, red;
+ enum pipe pipe;
+ int num_samples, length;
+ u32 index, word;
+
+ if (!blob) {
+ DRM_ERROR("Null Blob\n");
+ return -EINVAL;
+ }
+
+ degamma_data = (struct drm_palette *)blob->data;
+
+ if (degamma_data->version != GEN9_DEGAMMA_DATA_STRUCT_VERSION) {
+ DRM_ERROR("Invalid DeGamma Data struct version\n");
+ return -EINVAL;
+ }
+
+ pipe = to_intel_crtc(crtc)->pipe;
+ num_samples = degamma_data->num_samples;
+ if (num_samples != GEN9_SPLITGAMMA_MAX_VALS) {
+ DRM_ERROR("Invalid number of samples\n");
+ return -EINVAL;
+ }
+
+ length = num_samples * sizeof(struct drm_r32g32b32);
+ mode = I915_READ(GAMMA_MODE(pipe));
+
+ pal_prec_index = _PREC_PAL_INDEX(pipe);
+ pal_prec_data = _PREC_PAL_DATA(pipe);
+
+ correction_values = (struct drm_r32g32b32 *)&degamma_data->lut;
+ index = I915_READ(pal_prec_index);
+ index |= GEN9_INDEX_AUTO_INCREMENT | GEN9_INDEX_SPLIT_MODE;
+ I915_WRITE(pal_prec_index, index);
+
+ while (count < num_samples) {
+ blue = correction_values[count].b32;
+ green = correction_values[count].g32;
+ red = correction_values[count].r32;
+
+ word = gen9_write_10bit_gamma_precision(red, green, blue);
+ I915_WRITE(pal_prec_data, word);
+ count++;
+ }
+
+ mode &= ~GAMMA_MODE_MODE_MASK;
+ I915_WRITE(GAMMA_MODE(pipe), mode | GAMMA_MODE_MODE_SPLIT);
+
+ /* Enable DeGamma on Pipe */
+ I915_WRITE(_PIPE_CGM_CONTROL(pipe),
+ I915_READ(_PIPE_CGM_CONTROL(pipe)) | CGM_DEGAMMA_EN);
+
+ DRM_DEBUG_DRIVER("DeGamma correction enabled on Pipe %c\n",
+ pipe_name(pipe));
+
+ return 0;
+}
+
int chv_set_degamma(struct drm_device *dev, struct drm_property_blob *blob,
struct drm_crtc *crtc)
{
@@ -640,6 +706,8 @@ void intel_color_manager_crtc_commit(struct drm_device *dev,
/* degamma correction */
if (IS_CHERRYVIEW(dev))
ret = chv_set_degamma(dev, blob, crtc);
+ else if (IS_BROADWELL(dev) || IS_GEN9(dev))
+ ret = gen9_set_degamma(dev, blob, crtc);

if (ret)
DRM_ERROR("set degamma correction failed\n");
diff --git a/drivers/gpu/drm/i915/intel_color_manager.h b/drivers/gpu/drm/i915/intel_color_manager.h
index fa9d0b0..ca89f25 100644
--- a/drivers/gpu/drm/i915/intel_color_manager.h
+++ b/drivers/gpu/drm/i915/intel_color_manager.h
@@ -72,6 +72,8 @@
#define CHV_DEGAMMA_DATA_STRUCT_VERSION 1
#define CHV_DEGAMMA_MSB_SHIFT 2
#define CHV_DEGAMMA_GREEN_SHIFT 16
+/* Gen 9 */
+#define GEN9_DEGAMMA_DATA_STRUCT_VERSION 1

/* CSC correction */
#define CHV_CSC_DATA_STRUCT_VERSION 1
--
1.9.1

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