drm/i915: Polish CHV CGM CSC loading

Only load the CGM CSC based on the cgm_mode bit like we
do with the gamma/degamma LUTs. And make the function
naming and arguments consistent as well.

TODO: the code to convert the coefficients look totally
bogus. IIRC CHV uses two's complement format but the code
certainly doesn't generate that, so probably negative
coefficients are totally busted.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200303173313.28117-2-ville.syrjala@linux.intel.com
Reviewed-by: Swati Sharma <swati2.sharma@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index 98aefee..444980f 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -348,48 +348,43 @@ static void icl_load_csc_matrix(const struct intel_crtc_state *crtc_state)
                       crtc_state->csc_mode);
 }
 
-/*
- * Set up the pipe CSC unit on CherryView.
- */
-static void cherryview_load_csc_matrix(const struct intel_crtc_state *crtc_state)
+static void chv_load_cgm_csc(struct intel_crtc *crtc,
+                            const struct drm_property_blob *blob)
 {
-       struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+       const struct drm_color_ctm *ctm = blob->data;
        enum pipe pipe = crtc->pipe;
+       u16 coeffs[9];
+       int i;
 
-       if (crtc_state->hw.ctm) {
-               const struct drm_color_ctm *ctm = crtc_state->hw.ctm->data;
-               u16 coeffs[9] = {};
-               int i;
-
-               for (i = 0; i < ARRAY_SIZE(coeffs); i++) {
-                       u64 abs_coeff =
-                               ((1ULL << 63) - 1) & ctm->matrix[i];
-
-                       /* Round coefficient. */
-                       abs_coeff += 1 << (32 - 13);
-                       /* Clamp to hardware limits. */
-                       abs_coeff = clamp_val(abs_coeff, 0, CTM_COEFF_8_0 - 1);
-
-                       /* Write coefficients in S3.12 format. */
-                       if (ctm->matrix[i] & (1ULL << 63))
-                               coeffs[i] = 1 << 15;
-                       coeffs[i] |= ((abs_coeff >> 32) & 7) << 12;
-                       coeffs[i] |= (abs_coeff >> 20) & 0xfff;
-               }
+       for (i = 0; i < ARRAY_SIZE(coeffs); i++) {
+               u64 abs_coeff = ((1ULL << 63) - 1) & ctm->matrix[i];
 
-               intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF01(pipe),
-                              coeffs[1] << 16 | coeffs[0]);
-               intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF23(pipe),
-                              coeffs[3] << 16 | coeffs[2]);
-               intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF45(pipe),
-                              coeffs[5] << 16 | coeffs[4]);
-               intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF67(pipe),
-                              coeffs[7] << 16 | coeffs[6]);
-               intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF8(pipe), coeffs[8]);
+               /* Round coefficient. */
+               abs_coeff += 1 << (32 - 13);
+               /* Clamp to hardware limits. */
+               abs_coeff = clamp_val(abs_coeff, 0, CTM_COEFF_8_0 - 1);
+
+               coeffs[i] = 0;
+
+               /* Write coefficients in S3.12 format. */
+               if (ctm->matrix[i] & (1ULL << 63))
+                       coeffs[i] |= 1 << 15;
+
+               coeffs[i] |= ((abs_coeff >> 32) & 7) << 12;
+               coeffs[i] |= (abs_coeff >> 20) & 0xfff;
        }
 
-       intel_de_write(dev_priv, CGM_PIPE_MODE(pipe), crtc_state->cgm_mode);
+       intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF01(pipe),
+                      coeffs[1] << 16 | coeffs[0]);
+       intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF23(pipe),
+                      coeffs[3] << 16 | coeffs[2]);
+       intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF45(pipe),
+                      coeffs[5] << 16 | coeffs[4]);
+       intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF67(pipe),
+                      coeffs[7] << 16 | coeffs[6]);
+       intel_de_write(dev_priv, CGM_PIPE_CSC_COEFF8(pipe),
+                      coeffs[8]);
 }
 
 static u32 i9xx_lut_8(const struct drm_color_lut *color)
@@ -1020,10 +1015,13 @@ static void chv_load_cgm_gamma(struct intel_crtc *crtc,
 static void chv_load_luts(const struct intel_crtc_state *crtc_state)
 {
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
-       const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
+       struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct drm_property_blob *degamma_lut = crtc_state->hw.degamma_lut;
+       const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
+       const struct drm_property_blob *ctm = crtc_state->hw.ctm;
 
-       cherryview_load_csc_matrix(crtc_state);
+       if (crtc_state->cgm_mode & CGM_PIPE_MODE_CSC)
+               chv_load_cgm_csc(crtc, ctm);
 
        if (crtc_state->cgm_mode & CGM_PIPE_MODE_DEGAMMA)
                chv_load_cgm_degamma(crtc, degamma_lut);
@@ -1032,6 +1030,9 @@ static void chv_load_luts(const struct intel_crtc_state *crtc_state)
                chv_load_cgm_gamma(crtc, gamma_lut);
        else
                i965_load_luts(crtc_state);
+
+       intel_de_write(dev_priv, CGM_PIPE_MODE(crtc->pipe),
+                      crtc_state->cgm_mode);
 }
 
 void intel_color_load_luts(const struct intel_crtc_state *crtc_state)