/*
 * Copyright © 2016 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 */

#include "intel_color.h"
#include "intel_drv.h"

#define CTM_COEFF_SIGN  (1ULL << 63)

#define CTM_COEFF_1_0   (1ULL << 32)
#define CTM_COEFF_2_0   (CTM_COEFF_1_0 << 1)
#define CTM_COEFF_4_0   (CTM_COEFF_2_0 << 1)
#define CTM_COEFF_8_0   (CTM_COEFF_4_0 << 1)
#define CTM_COEFF_0_5   (CTM_COEFF_1_0 >> 1)
#define CTM_COEFF_0_25  (CTM_COEFF_0_5 >> 1)
#define CTM_COEFF_0_125 (CTM_COEFF_0_25 >> 1)

#define CTM_COEFF_LIMITED_RANGE ((235ULL - 16ULL) * CTM_COEFF_1_0 / 255)

#define CTM_COEFF_NEGATIVE(coeff)       (((coeff) & CTM_COEFF_SIGN) != 0)
#define CTM_COEFF_ABS(coeff)            ((coeff) & (CTM_COEFF_SIGN - 1))

#define LEGACY_LUT_LENGTH               256

/*
 * Extract the CSC coefficient from a CTM coefficient (in U32.32 fixed point
 * format). This macro takes the coefficient we want transformed and the
 * number of fractional bits.
 *
 * We only have a 9 bits precision window which slides depending on the value
 * of the CTM coefficient and we write the value from bit 3. We also round the
 * value.
 */
#define ILK_CSC_COEFF_FP(coeff, fbits)  \
        (clamp_val(((coeff) >> (32 - (fbits) - 3)) + 4, 0, 0xfff) & 0xff8)

#define ILK_CSC_COEFF_LIMITED_RANGE 0x0dc0
#define ILK_CSC_COEFF_1_0 0x7800

#define ILK_CSC_POSTOFF_LIMITED_RANGE (16 * (1 << 12) / 255)

static const u16 ilk_csc_off_zero[3] = {};

static const u16 ilk_csc_coeff_identity[9] = {
        ILK_CSC_COEFF_1_0, 0, 0,
        0, ILK_CSC_COEFF_1_0, 0,
        0, 0, ILK_CSC_COEFF_1_0,
};

static const u16 ilk_csc_postoff_limited_range[3] = {
        ILK_CSC_POSTOFF_LIMITED_RANGE,
        ILK_CSC_POSTOFF_LIMITED_RANGE,
        ILK_CSC_POSTOFF_LIMITED_RANGE,
};

static const u16 ilk_csc_coeff_limited_range[9] = {
        ILK_CSC_COEFF_LIMITED_RANGE, 0, 0,
        0, ILK_CSC_COEFF_LIMITED_RANGE, 0,
        0, 0, ILK_CSC_COEFF_LIMITED_RANGE,
};

/*
 * These values are direct register values specified in the Bspec,
 * for RGB->YUV conversion matrix (colorspace BT709)
 */
static const u16 ilk_csc_coeff_rgb_to_ycbcr[9] = {
        0x1e08, 0x9cc0, 0xb528,
        0x2ba8, 0x09d8, 0x37e8,
        0xbce8, 0x9ad8, 0x1e08,
};

/* Post offset values for RGB->YCBCR conversion */
static const u16 ilk_csc_postoff_rgb_to_ycbcr[3] = {
        0x0800, 0x0100, 0x0800,
};

static bool lut_is_legacy(const struct drm_property_blob *lut)
{
        return drm_color_lut_size(lut) == LEGACY_LUT_LENGTH;
}

static bool crtc_state_is_legacy_gamma(const struct intel_crtc_state *crtc_state)
{
        return !crtc_state->base.degamma_lut &&
                !crtc_state->base.ctm &&
                crtc_state->base.gamma_lut &&
                lut_is_legacy(crtc_state->base.gamma_lut);
}

/*
 * When using limited range, multiply the matrix given by userspace by
 * the matrix that we would use for the limited range.
 */
static u64 *ctm_mult_by_limited(u64 *result, const u64 *input)
{
        int i;

        for (i = 0; i < 9; i++) {
                u64 user_coeff = input[i];
                u32 limited_coeff = CTM_COEFF_LIMITED_RANGE;
                u32 abs_coeff = clamp_val(CTM_COEFF_ABS(user_coeff), 0,
                                          CTM_COEFF_4_0 - 1) >> 2;

                /*
                 * By scaling every co-efficient with limited range (16-235)
                 * vs full range (0-255) the final o/p will be scaled down to
                 * fit in the limited range supported by the panel.
                 */
                result[i] = mul_u32_u32(limited_coeff, abs_coeff) >> 30;
                result[i] |= user_coeff & CTM_COEFF_SIGN;
        }

        return result;
}

static void ilk_update_pipe_csc(struct intel_crtc *crtc,
                                const u16 preoff[3],
                                const u16 coeff[9],
                                const u16 postoff[3])
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;

        I915_WRITE(PIPE_CSC_PREOFF_HI(pipe), preoff[0]);
        I915_WRITE(PIPE_CSC_PREOFF_ME(pipe), preoff[1]);
        I915_WRITE(PIPE_CSC_PREOFF_LO(pipe), preoff[2]);

        I915_WRITE(PIPE_CSC_COEFF_RY_GY(pipe), coeff[0] << 16 | coeff[1]);
        I915_WRITE(PIPE_CSC_COEFF_BY(pipe), coeff[2] << 16);

        I915_WRITE(PIPE_CSC_COEFF_RU_GU(pipe), coeff[3] << 16 | coeff[4]);
        I915_WRITE(PIPE_CSC_COEFF_BU(pipe), coeff[5] << 16);

        I915_WRITE(PIPE_CSC_COEFF_RV_GV(pipe), coeff[6] << 16 | coeff[7]);
        I915_WRITE(PIPE_CSC_COEFF_BV(pipe), coeff[8] << 16);

        if (INTEL_GEN(dev_priv) >= 7) {
                I915_WRITE(PIPE_CSC_POSTOFF_HI(pipe), postoff[0]);
                I915_WRITE(PIPE_CSC_POSTOFF_ME(pipe), postoff[1]);
                I915_WRITE(PIPE_CSC_POSTOFF_LO(pipe), postoff[2]);
        }
}

static void icl_update_output_csc(struct intel_crtc *crtc,
                                  const u16 preoff[3],
                                  const u16 coeff[9],
                                  const u16 postoff[3])
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;

        I915_WRITE(PIPE_CSC_OUTPUT_PREOFF_HI(pipe), preoff[0]);
        I915_WRITE(PIPE_CSC_OUTPUT_PREOFF_ME(pipe), preoff[1]);
        I915_WRITE(PIPE_CSC_OUTPUT_PREOFF_LO(pipe), preoff[2]);

        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_RY_GY(pipe), coeff[0] << 16 | coeff[1]);
        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_BY(pipe), coeff[2] << 16);

        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_RU_GU(pipe), coeff[3] << 16 | coeff[4]);
        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_BU(pipe), coeff[5] << 16);

        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_RV_GV(pipe), coeff[6] << 16 | coeff[7]);
        I915_WRITE(PIPE_CSC_OUTPUT_COEFF_BV(pipe), coeff[8] << 16);

        I915_WRITE(PIPE_CSC_OUTPUT_POSTOFF_HI(pipe), postoff[0]);
        I915_WRITE(PIPE_CSC_OUTPUT_POSTOFF_ME(pipe), postoff[1]);
        I915_WRITE(PIPE_CSC_OUTPUT_POSTOFF_LO(pipe), postoff[2]);
}

static bool ilk_csc_limited_range(const struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);

        /*
         * FIXME if there's a gamma LUT after the CSC, we should
         * do the range compression using the gamma LUT instead.
         */
        return crtc_state->limited_color_range &&
                (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv) ||
                 IS_GEN_RANGE(dev_priv, 9, 10));
}

static void ilk_csc_convert_ctm(const struct intel_crtc_state *crtc_state,
                                u16 coeffs[9])
{
        const struct drm_color_ctm *ctm = crtc_state->base.ctm->data;
        const u64 *input;
        u64 temp[9];
        int i;

        if (ilk_csc_limited_range(crtc_state))
                input = ctm_mult_by_limited(temp, ctm->matrix);
        else
                input = ctm->matrix;

        /*
         * Convert fixed point S31.32 input to format supported by the
         * hardware.
         */
        for (i = 0; i < 9; i++) {
                u64 abs_coeff = ((1ULL << 63) - 1) & input[i];

                /*
                 * Clamp input value to min/max supported by
                 * hardware.
                 */
                abs_coeff = clamp_val(abs_coeff, 0, CTM_COEFF_4_0 - 1);

                coeffs[i] = 0;

                /* sign bit */
                if (CTM_COEFF_NEGATIVE(input[i]))
                        coeffs[i] |= 1 << 15;

                if (abs_coeff < CTM_COEFF_0_125)
                        coeffs[i] |= (3 << 12) |
                                ILK_CSC_COEFF_FP(abs_coeff, 12);
                else if (abs_coeff < CTM_COEFF_0_25)
                        coeffs[i] |= (2 << 12) |
                                ILK_CSC_COEFF_FP(abs_coeff, 11);
                else if (abs_coeff < CTM_COEFF_0_5)
                        coeffs[i] |= (1 << 12) |
                                ILK_CSC_COEFF_FP(abs_coeff, 10);
                else if (abs_coeff < CTM_COEFF_1_0)
                        coeffs[i] |= ILK_CSC_COEFF_FP(abs_coeff, 9);
                else if (abs_coeff < CTM_COEFF_2_0)
                        coeffs[i] |= (7 << 12) |
                                ILK_CSC_COEFF_FP(abs_coeff, 8);
                else
                        coeffs[i] |= (6 << 12) |
                                ILK_CSC_COEFF_FP(abs_coeff, 7);
        }
}

static void ilk_load_csc_matrix(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);
        bool limited_color_range = ilk_csc_limited_range(crtc_state);

        if (crtc_state->base.ctm) {
                u16 coeff[9];

                ilk_csc_convert_ctm(crtc_state, coeff);
                ilk_update_pipe_csc(crtc, ilk_csc_off_zero, coeff,
                                    limited_color_range ?
                                    ilk_csc_postoff_limited_range :
                                    ilk_csc_off_zero);
        } else if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB) {
                ilk_update_pipe_csc(crtc, ilk_csc_off_zero,
                                    ilk_csc_coeff_rgb_to_ycbcr,
                                    ilk_csc_postoff_rgb_to_ycbcr);
        } else if (limited_color_range) {
                ilk_update_pipe_csc(crtc, ilk_csc_off_zero,
                                    ilk_csc_coeff_limited_range,
                                    ilk_csc_postoff_limited_range);
        } else if (crtc_state->csc_enable) {
                /*
                 * On GLK+ both pipe CSC and degamma LUT are controlled
                 * by csc_enable. Hence for the cases where the degama
                 * LUT is needed but CSC is not we need to load an
                 * identity matrix.
                 */
                WARN_ON(!IS_CANNONLAKE(dev_priv) && !IS_GEMINILAKE(dev_priv));

                ilk_update_pipe_csc(crtc, ilk_csc_off_zero,
                                    ilk_csc_coeff_identity,
                                    ilk_csc_off_zero);
        }

        I915_WRITE(PIPE_CSC_MODE(crtc->pipe), crtc_state->csc_mode);
}

static void icl_load_csc_matrix(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);

        if (crtc_state->base.ctm) {
                u16 coeff[9];

                ilk_csc_convert_ctm(crtc_state, coeff);
                ilk_update_pipe_csc(crtc, ilk_csc_off_zero,
                                    coeff, ilk_csc_off_zero);
        }

        if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB) {
                icl_update_output_csc(crtc, ilk_csc_off_zero,
                                      ilk_csc_coeff_rgb_to_ycbcr,
                                      ilk_csc_postoff_rgb_to_ycbcr);
        } else if (crtc_state->limited_color_range) {
                icl_update_output_csc(crtc, ilk_csc_off_zero,
                                      ilk_csc_coeff_limited_range,
                                      ilk_csc_postoff_limited_range);
        }

        I915_WRITE(PIPE_CSC_MODE(crtc->pipe), 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)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;

        if (crtc_state->base.ctm) {
                const struct drm_color_ctm *ctm = crtc_state->base.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;
                }

                I915_WRITE(CGM_PIPE_CSC_COEFF01(pipe),
                           coeffs[1] << 16 | coeffs[0]);
                I915_WRITE(CGM_PIPE_CSC_COEFF23(pipe),
                           coeffs[3] << 16 | coeffs[2]);
                I915_WRITE(CGM_PIPE_CSC_COEFF45(pipe),
                           coeffs[5] << 16 | coeffs[4]);
                I915_WRITE(CGM_PIPE_CSC_COEFF67(pipe),
                           coeffs[7] << 16 | coeffs[6]);
                I915_WRITE(CGM_PIPE_CSC_COEFF8(pipe), coeffs[8]);
        }

        I915_WRITE(CGM_PIPE_MODE(pipe), crtc_state->cgm_mode);
}

/* i965+ "10.6" bit interpolated format "even DW" (low 8 bits) */
static u32 i965_lut_10p6_ldw(const struct drm_color_lut *color)
{
        return (color->red & 0xff) << 16 |
                (color->green & 0xff) << 8 |
                (color->blue & 0xff);
}

/* i965+ "10.6" interpolated format "odd DW" (high 8 bits) */
static u32 i965_lut_10p6_udw(const struct drm_color_lut *color)
{
        return (color->red >> 8) << 16 |
                (color->green >> 8) << 8 |
                (color->blue >> 8);
}

static u32 ilk_lut_10(const struct drm_color_lut *color)
{
        return drm_color_lut_extract(color->red, 10) << 20 |
                drm_color_lut_extract(color->green, 10) << 10 |
                drm_color_lut_extract(color->blue, 10);
}

/* Loads the legacy palette/gamma unit for the CRTC. */
static void i9xx_load_luts_internal(const struct intel_crtc_state *crtc_state,
                                    const struct drm_property_blob *blob)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;
        int i;

        if (HAS_GMCH(dev_priv)) {
                if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DSI))
                        assert_dsi_pll_enabled(dev_priv);
                else
                        assert_pll_enabled(dev_priv, pipe);
        }

        if (blob) {
                const struct drm_color_lut *lut = blob->data;

                for (i = 0; i < 256; i++) {
                        u32 word =
                                (drm_color_lut_extract(lut[i].red, 8) << 16) |
                                (drm_color_lut_extract(lut[i].green, 8) << 8) |
                                drm_color_lut_extract(lut[i].blue, 8);

                        if (HAS_GMCH(dev_priv))
                                I915_WRITE(PALETTE(pipe, i), word);
                        else
                                I915_WRITE(LGC_PALETTE(pipe, i), word);
                }
        }
}

static void i9xx_load_luts(const struct intel_crtc_state *crtc_state)
{
        i9xx_load_luts_internal(crtc_state, crtc_state->base.gamma_lut);
}

static void i9xx_color_commit(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);
        enum pipe pipe = crtc->pipe;
        u32 val;

        val = I915_READ(PIPECONF(pipe));
        val &= ~PIPECONF_GAMMA_MODE_MASK_I9XX;
        val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
        I915_WRITE(PIPECONF(pipe), val);
}

static void ilk_color_commit(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);
        enum pipe pipe = crtc->pipe;
        u32 val;

        val = I915_READ(PIPECONF(pipe));
        val &= ~PIPECONF_GAMMA_MODE_MASK_ILK;
        val |= PIPECONF_GAMMA_MODE(crtc_state->gamma_mode);
        I915_WRITE(PIPECONF(pipe), val);

        ilk_load_csc_matrix(crtc_state);
}

static void hsw_color_commit(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);

        I915_WRITE(GAMMA_MODE(crtc->pipe), crtc_state->gamma_mode);

        ilk_load_csc_matrix(crtc_state);
}

static void skl_color_commit(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);
        enum pipe pipe = crtc->pipe;
        u32 val = 0;

        /*
         * We don't (yet) allow userspace to control the pipe background color,
         * so force it to black, but apply pipe gamma and CSC appropriately
         * so that its handling will match how we program our planes.
         */
        if (crtc_state->gamma_enable)
                val |= SKL_BOTTOM_COLOR_GAMMA_ENABLE;
        if (crtc_state->csc_enable)
                val |= SKL_BOTTOM_COLOR_CSC_ENABLE;
        I915_WRITE(SKL_BOTTOM_COLOR(pipe), val);

        I915_WRITE(GAMMA_MODE(crtc->pipe), crtc_state->gamma_mode);

        if (INTEL_GEN(dev_priv) >= 11)
                icl_load_csc_matrix(crtc_state);
        else
                ilk_load_csc_matrix(crtc_state);
}

static void i965_load_lut_10p6(struct intel_crtc *crtc,
                               const struct drm_property_blob *blob)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        for (i = 0; i < lut_size - 1; i++) {
                I915_WRITE(PALETTE(pipe, 2 * i + 0),
                           i965_lut_10p6_ldw(&lut[i]));
                I915_WRITE(PALETTE(pipe, 2 * i + 1),
                           i965_lut_10p6_udw(&lut[i]));
        }

        I915_WRITE(PIPEGCMAX(pipe, 0), lut[i].red);
        I915_WRITE(PIPEGCMAX(pipe, 1), lut[i].green);
        I915_WRITE(PIPEGCMAX(pipe, 2), lut[i].blue);
}

static void i965_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;

        if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
                i9xx_load_luts(crtc_state);
        else
                i965_load_lut_10p6(crtc, gamma_lut);
}

static void ilk_load_lut_10(struct intel_crtc *crtc,
                            const struct drm_property_blob *blob)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        for (i = 0; i < lut_size; i++)
                I915_WRITE(PREC_PALETTE(pipe, i), ilk_lut_10(&lut[i]));
}

static void ilk_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;

        if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT)
                i9xx_load_luts(crtc_state);
        else
                ilk_load_lut_10(crtc, gamma_lut);
}

static int ivb_lut_10_size(u32 prec_index)
{
        if (prec_index & PAL_PREC_SPLIT_MODE)
                return 512;
        else
                return 1024;
}

/*
 * IVB/HSW Bspec / PAL_PREC_INDEX:
 * "Restriction : Index auto increment mode is not
 *  supported and must not be enabled."
 */
static void ivb_load_lut_10(struct intel_crtc *crtc,
                            const struct drm_property_blob *blob,
                            u32 prec_index)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        int hw_lut_size = ivb_lut_10_size(prec_index);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        for (i = 0; i < hw_lut_size; i++) {
                /* We discard half the user entries in split gamma mode */
                const struct drm_color_lut *entry =
                        &lut[i * (lut_size - 1) / (hw_lut_size - 1)];

                I915_WRITE(PREC_PAL_INDEX(pipe), prec_index++);
                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(entry));
        }

        /*
         * Reset the index, otherwise it prevents the legacy palette to be
         * written properly.
         */
        I915_WRITE(PREC_PAL_INDEX(pipe), 0);
}

/* On BDW+ the index auto increment mode actually works */
static void bdw_load_lut_10(struct intel_crtc *crtc,
                            const struct drm_property_blob *blob,
                            u32 prec_index)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        int hw_lut_size = ivb_lut_10_size(prec_index);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        I915_WRITE(PREC_PAL_INDEX(pipe), prec_index |
                   PAL_PREC_AUTO_INCREMENT);

        for (i = 0; i < hw_lut_size; i++) {
                /* We discard half the user entries in split gamma mode */
                const struct drm_color_lut *entry =
                        &lut[i * (lut_size - 1) / (hw_lut_size - 1)];

                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_10(entry));
        }

        /*
         * Reset the index, otherwise it prevents the legacy palette to be
         * written properly.
         */
        I915_WRITE(PREC_PAL_INDEX(pipe), 0);
}

static void ivb_load_lut_ext_max(struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;

        /* Program the max register to clamp values > 1.0. */
        I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 0), 1 << 16);
        I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 1), 1 << 16);
        I915_WRITE(PREC_PAL_EXT_GC_MAX(pipe, 2), 1 << 16);

        /*
         * Program the gc max 2 register to clamp values > 1.0.
         * ToDo: Extend the ABI to be able to program values
         * from 3.0 to 7.0
         */
        if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv)) {
                I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 0), 1 << 16);
                I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 1), 1 << 16);
                I915_WRITE(PREC_PAL_EXT2_GC_MAX(pipe, 2), 1 << 16);
        }
}

static void ivb_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;

        if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
                i9xx_load_luts(crtc_state);
        } else if (crtc_state->gamma_mode == GAMMA_MODE_MODE_SPLIT) {
                ivb_load_lut_10(crtc, degamma_lut, PAL_PREC_SPLIT_MODE |
                                PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
                ivb_load_lut_10(crtc, gamma_lut, PAL_PREC_SPLIT_MODE |
                                PAL_PREC_INDEX_VALUE(512));
        } else {
                const struct drm_property_blob *blob = gamma_lut ?: degamma_lut;

                ivb_load_lut_10(crtc, blob,
                                PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
        }
}

static void bdw_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;

        if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
                i9xx_load_luts(crtc_state);
        } else if (crtc_state->gamma_mode == GAMMA_MODE_MODE_SPLIT) {
                bdw_load_lut_10(crtc, degamma_lut, PAL_PREC_SPLIT_MODE |
                                PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
                bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_SPLIT_MODE |
                                PAL_PREC_INDEX_VALUE(512));
        } else {
                const struct drm_property_blob *blob = gamma_lut ?: degamma_lut;

                bdw_load_lut_10(crtc, blob,
                                PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
        }
}

static void glk_load_degamma_lut(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);
        enum pipe pipe = crtc->pipe;
        const u32 lut_size = INTEL_INFO(dev_priv)->color.degamma_lut_size;
        const struct drm_color_lut *lut = crtc_state->base.degamma_lut->data;
        u32 i;

        /*
         * When setting the auto-increment bit, the hardware seems to
         * ignore the index bits, so we need to reset it to index 0
         * separately.
         */
        I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), 0);
        I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), PRE_CSC_GAMC_AUTO_INCREMENT);

        for (i = 0; i < lut_size; i++) {
                /*
                 * First 33 entries represent range from 0 to 1.0
                 * 34th and 35th entry will represent extended range
                 * inputs 3.0 and 7.0 respectively, currently clamped
                 * at 1.0. Since the precision is 16bit, the user
                 * value can be directly filled to register.
                 * The pipe degamma table in GLK+ onwards doesn't
                 * support different values per channel, so this just
                 * programs green value which will be equal to Red and
                 * Blue into the lut registers.
                 * ToDo: Extend to max 7.0. Enable 32 bit input value
                 * as compared to just 16 to achieve this.
                 */
                I915_WRITE(PRE_CSC_GAMC_DATA(pipe), lut[i].green);
        }

        /* Clamp values > 1.0. */
        while (i++ < 35)
                I915_WRITE(PRE_CSC_GAMC_DATA(pipe), 1 << 16);
}

static void glk_load_degamma_lut_linear(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);
        enum pipe pipe = crtc->pipe;
        const u32 lut_size = INTEL_INFO(dev_priv)->color.degamma_lut_size;
        u32 i;

        /*
         * When setting the auto-increment bit, the hardware seems to
         * ignore the index bits, so we need to reset it to index 0
         * separately.
         */
        I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), 0);
        I915_WRITE(PRE_CSC_GAMC_INDEX(pipe), PRE_CSC_GAMC_AUTO_INCREMENT);

        for (i = 0; i < lut_size; i++) {
                u32 v = (i << 16) / (lut_size - 1);

                I915_WRITE(PRE_CSC_GAMC_DATA(pipe), v);
        }

        /* Clamp values > 1.0. */
        while (i++ < 35)
                I915_WRITE(PRE_CSC_GAMC_DATA(pipe), 1 << 16);
}

static void glk_load_luts(const struct intel_crtc_state *crtc_state)
{
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);

        /*
         * On GLK+ both pipe CSC and degamma LUT are controlled
         * by csc_enable. Hence for the cases where the CSC is
         * needed but degamma LUT is not we need to load a
         * linear degamma LUT. In fact we'll just always load
         * the degama LUT so that we don't have to reload
         * it every time the pipe CSC is being enabled.
         */
        if (crtc_state->base.degamma_lut)
                glk_load_degamma_lut(crtc_state);
        else
                glk_load_degamma_lut_linear(crtc_state);

        if (crtc_state->gamma_mode == GAMMA_MODE_MODE_8BIT) {
                i9xx_load_luts(crtc_state);
        } else {
                bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
        }
}

/* ilk+ "12.4" interpolated format (high 10 bits) */
static u32 ilk_lut_12p4_udw(const struct drm_color_lut *color)
{
        return (color->red >> 6) << 20 | (color->green >> 6) << 10 |
                (color->blue >> 6);
}

/* ilk+ "12.4" interpolated format (low 6 bits) */
static u32 ilk_lut_12p4_ldw(const struct drm_color_lut *color)
{
        return (color->red & 0x3f) << 24 | (color->green & 0x3f) << 14 |
                (color->blue & 0x3f) << 4;
}

static void
icl_load_gcmax(const struct intel_crtc_state *crtc_state,
               const struct drm_color_lut *color)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        enum pipe pipe = crtc->pipe;

        /* Fixme: LUT entries are 16 bit only, so we can prog 0xFFFF max */
        I915_WRITE(PREC_PAL_GC_MAX(pipe, 0), color->red);
        I915_WRITE(PREC_PAL_GC_MAX(pipe, 1), color->green);
        I915_WRITE(PREC_PAL_GC_MAX(pipe, 2), color->blue);
}

static void
icl_program_gamma_superfine_segment(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);
        const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
        const struct drm_color_lut *lut = blob->data;
        enum pipe pipe = crtc->pipe;
        u32 i;

        /*
         * Every entry in the multi-segment LUT is corresponding to a superfine
         * segment step which is 1/(8 * 128 * 256).
         *
         * Superfine segment has 9 entries, corresponding to values
         * 0, 1/(8 * 128 * 256), 2/(8 * 128 * 256) .... 8/(8 * 128 * 256).
         */
        I915_WRITE(PREC_PAL_MULTI_SEG_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);

        for (i = 0; i < 9; i++) {
                const struct drm_color_lut *entry = &lut[i];

                I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
                           ilk_lut_12p4_ldw(entry));
                I915_WRITE(PREC_PAL_MULTI_SEG_DATA(pipe),
                           ilk_lut_12p4_udw(entry));
        }
}

static void
icl_program_gamma_multi_segment(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);
        const struct drm_property_blob *blob = crtc_state->base.gamma_lut;
        const struct drm_color_lut *lut = blob->data;
        const struct drm_color_lut *entry;
        enum pipe pipe = crtc->pipe;
        u32 i;

        /*
         *
         * Program Fine segment (let's call it seg2)...
         *
         * Fine segment's step is 1/(128 * 256) ie 1/(128 * 256),  2/(128*256)
         * ... 256/(128*256). So in order to program fine segment of LUT we
         * need to pick every 8'th entry in LUT, and program 256 indexes.
         *
         * PAL_PREC_INDEX[0] and PAL_PREC_INDEX[1] map to seg2[1],
         * with seg2[0] being unused by the hardware.
         */
        I915_WRITE(PREC_PAL_INDEX(pipe), PAL_PREC_AUTO_INCREMENT);
        for (i = 1; i < 257; i++) {
                entry = &lut[i * 8];
                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
        }

        /*
         * Program Coarse segment (let's call it seg3)...
         *
         * Coarse segment's starts from index 0 and it's step is 1/256 ie 0,
         * 1/256, 2/256 ...256/256. As per the description of each entry in LUT
         * above, we need to pick every (8 * 128)th entry in LUT, and
         * program 256 of those.
         *
         * Spec is not very clear about if entries seg3[0] and seg3[1] are
         * being used or not, but we still need to program these to advance
         * the index.
         */
        for (i = 0; i < 256; i++) {
                entry = &lut[i * 8 * 128];
                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_ldw(entry));
                I915_WRITE(PREC_PAL_DATA(pipe), ilk_lut_12p4_udw(entry));
        }

        /* The last entry in the LUT is to be programmed in GCMAX */
        entry = &lut[256 * 8 * 128];
        icl_load_gcmax(crtc_state, entry);
        ivb_load_lut_ext_max(crtc);
}

static void icl_load_luts(const struct intel_crtc_state *crtc_state)
{
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);

        if (crtc_state->base.degamma_lut)
                glk_load_degamma_lut(crtc_state);

        switch (crtc_state->gamma_mode & GAMMA_MODE_MODE_MASK) {
        case GAMMA_MODE_MODE_8BIT:
                i9xx_load_luts(crtc_state);
                break;

        case GAMMA_MODE_MODE_12BIT_MULTI_SEGMENTED:
                icl_program_gamma_superfine_segment(crtc_state);
                icl_program_gamma_multi_segment(crtc_state);
                break;

        default:
                bdw_load_lut_10(crtc, gamma_lut, PAL_PREC_INDEX_VALUE(0));
                ivb_load_lut_ext_max(crtc);
        }
}

static u32 chv_cgm_degamma_ldw(const struct drm_color_lut *color)
{
        return drm_color_lut_extract(color->green, 14) << 16 |
                drm_color_lut_extract(color->blue, 14);
}

static u32 chv_cgm_degamma_udw(const struct drm_color_lut *color)
{
        return drm_color_lut_extract(color->red, 14);
}

static void chv_load_cgm_degamma(struct intel_crtc *crtc,
                                 const struct drm_property_blob *blob)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        for (i = 0; i < lut_size; i++) {
                I915_WRITE(CGM_PIPE_DEGAMMA(pipe, i, 0),
                           chv_cgm_degamma_ldw(&lut[i]));
                I915_WRITE(CGM_PIPE_DEGAMMA(pipe, i, 1),
                           chv_cgm_degamma_udw(&lut[i]));
        }
}

static u32 chv_cgm_gamma_ldw(const struct drm_color_lut *color)
{
        return drm_color_lut_extract(color->green, 10) << 16 |
                drm_color_lut_extract(color->blue, 10);
}

static u32 chv_cgm_gamma_udw(const struct drm_color_lut *color)
{
        return drm_color_lut_extract(color->red, 10);
}

static void chv_load_cgm_gamma(struct intel_crtc *crtc,
                               const struct drm_property_blob *blob)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct drm_color_lut *lut = blob->data;
        int i, lut_size = drm_color_lut_size(blob);
        enum pipe pipe = crtc->pipe;

        for (i = 0; i < lut_size; i++) {
                I915_WRITE(CGM_PIPE_GAMMA(pipe, i, 0),
                           chv_cgm_gamma_ldw(&lut[i]));
                I915_WRITE(CGM_PIPE_GAMMA(pipe, i, 1),
                           chv_cgm_gamma_udw(&lut[i]));
        }
}

static void chv_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;

        cherryview_load_csc_matrix(crtc_state);

        if (crtc_state_is_legacy_gamma(crtc_state)) {
                i9xx_load_luts(crtc_state);
                return;
        }

        if (degamma_lut)
                chv_load_cgm_degamma(crtc, degamma_lut);

        if (gamma_lut)
                chv_load_cgm_gamma(crtc, gamma_lut);
}

void intel_color_load_luts(const struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);

        dev_priv->display.load_luts(crtc_state);
}

void intel_color_commit(const struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);

        dev_priv->display.color_commit(crtc_state);
}

int intel_color_check(struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);

        return dev_priv->display.color_check(crtc_state);
}

void intel_color_get_config(struct intel_crtc_state *crtc_state)

{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);

        if (dev_priv->display.read_luts)
                dev_priv->display.read_luts(crtc_state);
}

static bool need_plane_update(struct intel_plane *plane,
                              const struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(plane->base.dev);

        /*
         * On pre-SKL the pipe gamma enable and pipe csc enable for
         * the pipe bottom color are configured via the primary plane.
         * We have to reconfigure that even if the plane is inactive.
         */
        return crtc_state->active_planes & BIT(plane->id) ||
                (INTEL_GEN(dev_priv) < 9 &&
                 plane->id == PLANE_PRIMARY);
}

static int
intel_color_add_affected_planes(struct intel_crtc_state *new_crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->base.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        struct intel_atomic_state *state =
                to_intel_atomic_state(new_crtc_state->base.state);
        const struct intel_crtc_state *old_crtc_state =
                intel_atomic_get_old_crtc_state(state, crtc);
        struct intel_plane *plane;

        if (!new_crtc_state->base.active ||
            drm_atomic_crtc_needs_modeset(&new_crtc_state->base))
                return 0;

        if (new_crtc_state->gamma_enable == old_crtc_state->gamma_enable &&
            new_crtc_state->csc_enable == old_crtc_state->csc_enable)
                return 0;

        for_each_intel_plane_on_crtc(&dev_priv->drm, crtc, plane) {
                struct intel_plane_state *plane_state;

                if (!need_plane_update(plane, new_crtc_state))
                        continue;

                plane_state = intel_atomic_get_plane_state(state, plane);
                if (IS_ERR(plane_state))
                        return PTR_ERR(plane_state);

                new_crtc_state->update_planes |= BIT(plane->id);
        }

        return 0;
}

static int check_lut_size(const struct drm_property_blob *lut, int expected)
{
        int len;

        if (!lut)
                return 0;

        len = drm_color_lut_size(lut);
        if (len != expected) {
                DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n",
                              len, expected);
                return -EINVAL;
        }

        return 0;
}

static int check_luts(const struct intel_crtc_state *crtc_state)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
        const struct drm_property_blob *gamma_lut = crtc_state->base.gamma_lut;
        const struct drm_property_blob *degamma_lut = crtc_state->base.degamma_lut;
        int gamma_length, degamma_length;
        u32 gamma_tests, degamma_tests;

        /* Always allow legacy gamma LUT with no further checking. */
        if (crtc_state_is_legacy_gamma(crtc_state))
                return 0;

        /* C8 relies on its palette being stored in the legacy LUT */
        if (crtc_state->c8_planes) {
                DRM_DEBUG_KMS("C8 pixelformat requires the legacy LUT\n");
                return -EINVAL;
        }

        degamma_length = INTEL_INFO(dev_priv)->color.degamma_lut_size;
        gamma_length = INTEL_INFO(dev_priv)->color.gamma_lut_size;
        degamma_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
        gamma_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;

        if (check_lut_size(degamma_lut, degamma_length) ||
            check_lut_size(gamma_lut, gamma_length))
                return -EINVAL;

        if (drm_color_lut_check(degamma_lut, degamma_tests) ||
            drm_color_lut_check(gamma_lut, gamma_tests))
                return -EINVAL;

        return 0;
}

static u32 i9xx_gamma_mode(struct intel_crtc_state *crtc_state)
{
        if (!crtc_state->gamma_enable ||
            crtc_state_is_legacy_gamma(crtc_state))
                return GAMMA_MODE_MODE_8BIT;
        else
                return GAMMA_MODE_MODE_10BIT; /* i965+ only */
}

static int i9xx_color_check(struct intel_crtc_state *crtc_state)
{
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        crtc_state->gamma_enable =
                crtc_state->base.gamma_lut &&
                !crtc_state->c8_planes;

        crtc_state->gamma_mode = i9xx_gamma_mode(crtc_state);

        ret = intel_color_add_affected_planes(crtc_state);
        if (ret)
                return ret;

        return 0;
}

static u32 chv_cgm_mode(const struct intel_crtc_state *crtc_state)
{
        u32 cgm_mode = 0;

        if (crtc_state_is_legacy_gamma(crtc_state))
                return 0;

        if (crtc_state->base.degamma_lut)
                cgm_mode |= CGM_PIPE_MODE_DEGAMMA;
        if (crtc_state->base.ctm)
                cgm_mode |= CGM_PIPE_MODE_CSC;
        if (crtc_state->base.gamma_lut)
                cgm_mode |= CGM_PIPE_MODE_GAMMA;

        return cgm_mode;
}

/*
 * CHV color pipeline:
 * u0.10 -> CGM degamma -> u0.14 -> CGM csc -> u0.14 -> CGM gamma ->
 * u0.10 -> WGC csc -> u0.10 -> pipe gamma -> u0.10
 *
 * We always bypass the WGC csc and use the CGM csc
 * instead since it has degamma and better precision.
 */
static int chv_color_check(struct intel_crtc_state *crtc_state)
{
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        /*
         * Pipe gamma will be used only for the legacy LUT.
         * Otherwise we bypass it and use the CGM gamma instead.
         */
        crtc_state->gamma_enable =
                crtc_state_is_legacy_gamma(crtc_state) &&
                !crtc_state->c8_planes;

        crtc_state->gamma_mode = GAMMA_MODE_MODE_8BIT;

        crtc_state->cgm_mode = chv_cgm_mode(crtc_state);

        ret = intel_color_add_affected_planes(crtc_state);
        if (ret)
                return ret;

        return 0;
}

static u32 ilk_gamma_mode(const struct intel_crtc_state *crtc_state)
{
        if (!crtc_state->gamma_enable ||
            crtc_state_is_legacy_gamma(crtc_state))
                return GAMMA_MODE_MODE_8BIT;
        else
                return GAMMA_MODE_MODE_10BIT;
}

static int ilk_color_check(struct intel_crtc_state *crtc_state)
{
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        crtc_state->gamma_enable =
                crtc_state->base.gamma_lut &&
                !crtc_state->c8_planes;

        /*
         * We don't expose the ctm on ilk/snb currently,
         * nor do we enable YCbCr output. Also RGB limited
         * range output is handled by the hw automagically.
         */
        crtc_state->csc_enable = false;

        crtc_state->gamma_mode = ilk_gamma_mode(crtc_state);

        crtc_state->csc_mode = 0;

        ret = intel_color_add_affected_planes(crtc_state);
        if (ret)
                return ret;

        return 0;
}

static u32 ivb_gamma_mode(const struct intel_crtc_state *crtc_state)
{
        if (!crtc_state->gamma_enable ||
            crtc_state_is_legacy_gamma(crtc_state))
                return GAMMA_MODE_MODE_8BIT;
        else if (crtc_state->base.gamma_lut &&
                 crtc_state->base.degamma_lut)
                return GAMMA_MODE_MODE_SPLIT;
        else
                return GAMMA_MODE_MODE_10BIT;
}

static u32 ivb_csc_mode(const struct intel_crtc_state *crtc_state)
{
        bool limited_color_range = ilk_csc_limited_range(crtc_state);

        /*
         * CSC comes after the LUT in degamma, RGB->YCbCr,
         * and RGB full->limited range mode.
         */
        if (crtc_state->base.degamma_lut ||
            crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
            limited_color_range)
                return 0;

        return CSC_POSITION_BEFORE_GAMMA;
}

static int ivb_color_check(struct intel_crtc_state *crtc_state)
{
        bool limited_color_range = ilk_csc_limited_range(crtc_state);
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        crtc_state->gamma_enable =
                (crtc_state->base.gamma_lut ||
                 crtc_state->base.degamma_lut) &&
                !crtc_state->c8_planes;

        crtc_state->csc_enable =
                crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
                crtc_state->base.ctm || limited_color_range;

        crtc_state->gamma_mode = ivb_gamma_mode(crtc_state);

        crtc_state->csc_mode = ivb_csc_mode(crtc_state);

        ret = intel_color_add_affected_planes(crtc_state);
        if (ret)
                return ret;

        return 0;
}

static u32 glk_gamma_mode(const struct intel_crtc_state *crtc_state)
{
        if (!crtc_state->gamma_enable ||
            crtc_state_is_legacy_gamma(crtc_state))
                return GAMMA_MODE_MODE_8BIT;
        else
                return GAMMA_MODE_MODE_10BIT;
}

static int glk_color_check(struct intel_crtc_state *crtc_state)
{
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        crtc_state->gamma_enable =
                crtc_state->base.gamma_lut &&
                !crtc_state->c8_planes;

        /* On GLK+ degamma LUT is controlled by csc_enable */
        crtc_state->csc_enable =
                crtc_state->base.degamma_lut ||
                crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
                crtc_state->base.ctm || crtc_state->limited_color_range;

        crtc_state->gamma_mode = glk_gamma_mode(crtc_state);

        crtc_state->csc_mode = 0;

        ret = intel_color_add_affected_planes(crtc_state);
        if (ret)
                return ret;

        return 0;
}

static u32 icl_gamma_mode(const struct intel_crtc_state *crtc_state)
{
        u32 gamma_mode = 0;

        if (crtc_state->base.degamma_lut)
                gamma_mode |= PRE_CSC_GAMMA_ENABLE;

        if (crtc_state->base.gamma_lut &&
            !crtc_state->c8_planes)
                gamma_mode |= POST_CSC_GAMMA_ENABLE;

        if (!crtc_state->base.gamma_lut ||
            crtc_state_is_legacy_gamma(crtc_state))
                gamma_mode |= GAMMA_MODE_MODE_8BIT;
        else
                gamma_mode |= GAMMA_MODE_MODE_12BIT_MULTI_SEGMENTED;

        return gamma_mode;
}

static u32 icl_csc_mode(const struct intel_crtc_state *crtc_state)
{
        u32 csc_mode = 0;

        if (crtc_state->base.ctm)
                csc_mode |= ICL_CSC_ENABLE;

        if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_RGB ||
            crtc_state->limited_color_range)
                csc_mode |= ICL_OUTPUT_CSC_ENABLE;

        return csc_mode;
}

static int icl_color_check(struct intel_crtc_state *crtc_state)
{
        int ret;

        ret = check_luts(crtc_state);
        if (ret)
                return ret;

        crtc_state->gamma_mode = icl_gamma_mode(crtc_state);

        crtc_state->csc_mode = icl_csc_mode(crtc_state);

        return 0;
}

void intel_color_init(struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        bool has_ctm = INTEL_INFO(dev_priv)->color.degamma_lut_size != 0;

        drm_mode_crtc_set_gamma_size(&crtc->base, 256);

        if (HAS_GMCH(dev_priv)) {
                if (IS_CHERRYVIEW(dev_priv)) {
                        dev_priv->display.color_check = chv_color_check;
                        dev_priv->display.color_commit = i9xx_color_commit;
                        dev_priv->display.load_luts = chv_load_luts;
                } else if (INTEL_GEN(dev_priv) >= 4) {
                        dev_priv->display.color_check = i9xx_color_check;
                        dev_priv->display.color_commit = i9xx_color_commit;
                        dev_priv->display.load_luts = i965_load_luts;
                } else {
                        dev_priv->display.color_check = i9xx_color_check;
                        dev_priv->display.color_commit = i9xx_color_commit;
                        dev_priv->display.load_luts = i9xx_load_luts;
                }
        } else {
                if (INTEL_GEN(dev_priv) >= 11)
                        dev_priv->display.color_check = icl_color_check;
                else if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
                        dev_priv->display.color_check = glk_color_check;
                else if (INTEL_GEN(dev_priv) >= 7)
                        dev_priv->display.color_check = ivb_color_check;
                else
                        dev_priv->display.color_check = ilk_color_check;

                if (INTEL_GEN(dev_priv) >= 9)
                        dev_priv->display.color_commit = skl_color_commit;
                else if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
                        dev_priv->display.color_commit = hsw_color_commit;
                else
                        dev_priv->display.color_commit = ilk_color_commit;

                if (INTEL_GEN(dev_priv) >= 11)
                        dev_priv->display.load_luts = icl_load_luts;
                else if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
                        dev_priv->display.load_luts = glk_load_luts;
                else if (INTEL_GEN(dev_priv) >= 8)
                        dev_priv->display.load_luts = bdw_load_luts;
                else if (INTEL_GEN(dev_priv) >= 7)
                        dev_priv->display.load_luts = ivb_load_luts;
                else
                        dev_priv->display.load_luts = ilk_load_luts;
        }

        drm_crtc_enable_color_mgmt(&crtc->base,
                                   INTEL_INFO(dev_priv)->color.degamma_lut_size,
                                   has_ctm,
                                   INTEL_INFO(dev_priv)->color.gamma_lut_size);
}