drm/i915: Add PIPECONF YCbCr 4:4:4 programming for ILK-IVB

On ILK-IVB the pipe colorspace is configured via PIPECONF
(as opposed to PIPEMISC in BDW+). Let's configure+readout
that stuff correctly.

Enabling YCbCr 4:4:4 output will now be a simple matter of
setting crtc_state->output_format appropriately in the encoder
.compute_config(). However, when we do that we must be
aware of the fact that YCbCr DP output doesn't seem to work
on ILK (resulting image is totally garbled), but on SNB+
it works fine. However HDMI YCbCr output does work correctly
even on ILK.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190718145053.25808-13-ville.syrjala@linux.intel.comReviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -9420,9 +9420,19 @@ static void ironlake_set_pipeconf(const struct intel_crtc_state *crtc_state)
 	else
 		val |= PIPECONF_PROGRESSIVE;
 
+	/*
+	 * This would end up with an odd purple hue over
+	 * the entire display. Make sure we don't do it.
+	 */
+	WARN_ON(crtc_state->limited_color_range &&
+		crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB);
+
 	if (crtc_state->limited_color_range)
 		val |= PIPECONF_COLOR_RANGE_SELECT;
 
+	if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB)
+		val |= PIPECONF_OUTPUT_COLORSPACE_YUV709;
+
 	val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
 
 	I915_WRITE(PIPECONF(pipe), val);
@@ -9959,7 +9969,6 @@ static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
 	if (!wakeref)
 		return false;
 
-	pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
 	pipe_config->cpu_transcoder = (enum transcoder) crtc->pipe;
 	pipe_config->shared_dpll = NULL;
 
@@ -9988,6 +9997,16 @@ static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
 	if (tmp & PIPECONF_COLOR_RANGE_SELECT)
 		pipe_config->limited_color_range = true;
 
+	switch (tmp & PIPECONF_OUTPUT_COLORSPACE_MASK) {
+	case PIPECONF_OUTPUT_COLORSPACE_YUV601:
+	case PIPECONF_OUTPUT_COLORSPACE_YUV709:
+		pipe_config->output_format = INTEL_OUTPUT_FORMAT_YCBCR444;
+		break;
+	default:
+		pipe_config->output_format = INTEL_OUTPUT_FORMAT_RGB;
+		break;
+	}
+
 	pipe_config->gamma_mode = (tmp & PIPECONF_GAMMA_MODE_MASK_ILK) >>
 		PIPECONF_GAMMA_MODE_SHIFT;
 

drivers/gpu/drm/i915/i915_reg.h

@@ -5683,6 +5683,10 @@ enum {
 #define   PIPECONF_CXSR_DOWNCLOCK	(1 << 16)
 #define   PIPECONF_EDP_RR_MODE_SWITCH_VLV	(1 << 14)
 #define   PIPECONF_COLOR_RANGE_SELECT	(1 << 13)
+#define   PIPECONF_OUTPUT_COLORSPACE_MASK	(3 << 11) /* ilk-ivb */
+#define   PIPECONF_OUTPUT_COLORSPACE_RGB	(0 << 11) /* ilk-ivb */
+#define   PIPECONF_OUTPUT_COLORSPACE_YUV601	(1 << 11) /* ilk-ivb */
+#define   PIPECONF_OUTPUT_COLORSPACE_YUV709	(2 << 11) /* ilk-ivb */
 #define   PIPECONF_OUTPUT_COLORSPACE_YUV_HSW	(1 << 11) /* hsw only */
 #define   PIPECONF_BPC_MASK	(0x7 << 5)
 #define   PIPECONF_8BPC		(0 << 5)