drm/i915/display: Extract i965_read_luts()

For i965, add hw read out to create hw blob of gamma
lut values.

Review comments from old series:
https://patchwork.freedesktop.org/series/58039/

v4:  -No need to initialize *blob [Jani]
     -Removed right shifts [Jani]
     -Dropped dev local var [Jani]
v5:  -Returned blob instead of assigning it internally
      within the function [Ville]
     -Renamed i965_get_color_config() to i965_read_lut() [Ville]
     -Renamed i965_get_gamma_config_10p6() to i965_read_gamma_lut_10p6()
      [Ville]
v9:  -Typo and 80 character limit [Uma]
     -Made read func para as const [Ville, Uma]
     -Renamed i965_read_gamma_lut_10p6() to i965_read_lut_10p6() [Ville, Uma]
v10: -Swapped ldw and udw while creating hw blob [Jani]
     -Added last index rgb lut value from PIPEGCMAX to h/w blob [Jani]

Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1568030503-26747-3-git-send-email-swati2.sharma@intel.com

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

@@ -1569,6 +1569,55 @@ static void i9xx_read_luts(struct intel_crtc_state *crtc_state)
 	crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
 }
 
+static struct drm_property_blob *
+i965_read_lut_10p6(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	u32 lut_size = INTEL_INFO(dev_priv)->color.gamma_lut_size;
+	enum pipe pipe = crtc->pipe;
+	struct drm_property_blob *blob;
+	struct drm_color_lut *blob_data;
+	u32 i, val1, val2;
+
+	blob = drm_property_create_blob(&dev_priv->drm,
+					sizeof(struct drm_color_lut) * lut_size,
+					NULL);
+	if (IS_ERR(blob))
+		return NULL;
+
+	blob_data = blob->data;
+
+	for (i = 0; i < lut_size - 1; i++) {
+		val1 = I915_READ(PALETTE(pipe, 2 * i + 0));
+		val2 = I915_READ(PALETTE(pipe, 2 * i + 1));
+
+		blob_data[i].red = REG_FIELD_GET(PALETTE_RED_MASK, val2) << 8 |
+						 REG_FIELD_GET(PALETTE_RED_MASK, val1);
+		blob_data[i].green = REG_FIELD_GET(PALETTE_GREEN_MASK, val2) << 8 |
+						   REG_FIELD_GET(PALETTE_GREEN_MASK, val1);
+		blob_data[i].blue = REG_FIELD_GET(PALETTE_BLUE_MASK, val2) << 8 |
+						  REG_FIELD_GET(PALETTE_BLUE_MASK, val1);
+	}
+
+	blob_data[i].red = REG_FIELD_GET(PIPEGCMAX_RGB_MASK,
+					 I915_READ(PIPEGCMAX(pipe, 0)));
+	blob_data[i].green = REG_FIELD_GET(PIPEGCMAX_RGB_MASK,
+					   I915_READ(PIPEGCMAX(pipe, 1)));
+	blob_data[i].blue = REG_FIELD_GET(PIPEGCMAX_RGB_MASK,
+					  I915_READ(PIPEGCMAX(pipe, 2)));
+
+	return blob;
+}
+
+static void i965_read_luts(struct intel_crtc_state *crtc_state)
+{
+	if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
+		crtc_state->base.gamma_lut = i9xx_read_lut_8(crtc_state);
+	else
+		crtc_state->base.gamma_lut = i965_read_lut_10p6(crtc_state);
+}
+
 static struct drm_property_blob *
 ilk_read_lut_10(const struct intel_crtc_state *crtc_state)
 {
@@ -1672,6 +1721,7 @@ void intel_color_init(struct intel_crtc *crtc)
 			dev_priv->display.color_check = i9xx_color_check;
 			dev_priv->display.color_commit = i9xx_color_commit;
 			dev_priv->display.load_luts = i965_load_luts;
+			dev_priv->display.read_luts = i965_read_luts;
 		} else {
 			dev_priv->display.color_check = i9xx_color_check;
 			dev_priv->display.color_commit = i9xx_color_commit;

drivers/gpu/drm/i915/i915_reg.h

@@ -3558,6 +3558,9 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define _PALETTE_A		0xa000
 #define _PALETTE_B		0xa800
 #define _CHV_PALETTE_C		0xc000
+#define PALETTE_RED_MASK        REG_GENMASK(23, 16)
+#define PALETTE_GREEN_MASK      REG_GENMASK(15, 8)
+#define PALETTE_BLUE_MASK       REG_GENMASK(7, 0)
 #define PALETTE(pipe, i)	_MMIO(DISPLAY_MMIO_BASE(dev_priv) + \
 				      _PICK((pipe), _PALETTE_A,		\
 					    _PALETTE_B, _CHV_PALETTE_C) + \
@@ -5767,6 +5770,7 @@ enum {
 
 #define  _PIPEAGCMAX           0x70010
 #define  _PIPEBGCMAX           0x71010
+#define PIPEGCMAX_RGB_MASK     REG_GENMASK(15, 0)
 #define PIPEGCMAX(pipe, i)     _MMIO_PIPE2(pipe, _PIPEAGCMAX + (i) * 4)
 
 #define _PIPE_MISC_A			0x70030