[v5 20/24] drm/i915/color: Program Pre-CSC registers
Uma Shankar
uma.shankar at intel.com
Wed Jul 2 09:19:32 UTC 2025
From: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
Add callback for programming Pre-CSC LUT for TGL and beyond
v2: Add DSB support
v3: Add support for single segment 1D LUT color op
Signed-off-by: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
---
drivers/gpu/drm/i915/display/intel_color.c | 104 +++++++++++++++++++++
1 file changed, 104 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
index c7378af8fbdf..75981fe232bf 100644
--- a/drivers/gpu/drm/i915/display/intel_color.c
+++ b/drivers/gpu/drm/i915/display/intel_color.c
@@ -3945,6 +3945,109 @@ xelpd_load_plane_csc_matrix(struct intel_dsb *dsb,
ctm_to_twos_complement(input[11], 0, 12));
}
+static void
+xelpd_program_plane_pre_csc_lut(struct intel_dsb *dsb,
+ const struct intel_plane_state *plane_state)
+{
+ struct intel_display *display = to_intel_display(plane_state);
+ const struct drm_plane_state *state = &plane_state->uapi;
+ enum pipe pipe = to_intel_plane(state->plane)->pipe;
+ enum plane_id plane = to_intel_plane(state->plane)->id;
+ const struct drm_color_lut_32 *pre_csc_lut = plane_state->hw.degamma_lut->data;
+ u32 i, lut_size;
+ bool is_single_seg = drm_color_lut_32_size(plane_state->hw.degamma_lut) == 128 ?
+ true : false;
+
+ if (icl_is_hdr_plane(display, plane)) {
+ lut_size = 128;
+
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_INDEX_ENH(pipe, plane, 0),
+ PLANE_PAL_PREC_AUTO_INCREMENT);
+
+ if (pre_csc_lut) {
+ for (i = 0; i < lut_size; i++) {
+ u32 lut_val = is_single_seg ?
+ drm_color_lut_32_extract(pre_csc_lut[i].green, 24) :
+ (pre_csc_lut[i].green & 0xffffff);
+
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA_ENH(pipe, plane, 0),
+ lut_val);
+ }
+
+ /* Program the max register to clamp values > 1.0. */
+ /* ToDo: Restrict to 0x7ffffff*/
+ do {
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA_ENH(pipe, plane, 0),
+ is_single_seg ? (1 << 24) :
+ pre_csc_lut[i].green);
+ } while (i++ > 130);
+ } else {
+ for (i = 0; i < lut_size; i++) {
+ u32 v = (i * ((1 << 24) - 1)) / (lut_size - 1);
+
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA_ENH(pipe, plane, 0), v);
+ }
+
+ do {
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA_ENH(pipe, plane, 0),
+ 1 << 24);
+ } while (i++ < 130);
+ }
+
+ intel_de_write_dsb(display, dsb, PLANE_PRE_CSC_GAMC_INDEX_ENH(pipe, plane, 0), 0);
+ } else {
+ lut_size = 32;
+
+ /*
+ * First 3 planes are HDR, so reduce by 3 to get to the right
+ * SDR plane offset
+ */
+ plane = plane - 3;
+
+ intel_de_write_dsb(display, dsb, PLANE_PRE_CSC_GAMC_INDEX(pipe, plane, 0),
+ PLANE_PAL_PREC_AUTO_INCREMENT);
+
+ if (pre_csc_lut) {
+ for (i = 0; i < lut_size; i++)
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA(pipe, plane, 0),
+ pre_csc_lut[i].green);
+ /* Program the max register to clamp values > 1.0. */
+ while (i < 35)
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA(pipe, plane, 0),
+ pre_csc_lut[i++].green);
+ } else {
+ for (i = 0; i < lut_size; i++) {
+ u32 v = (i * ((1 << 16) - 1)) / (lut_size - 1);
+
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA(pipe, plane, 0), v);
+ }
+
+ do {
+ intel_de_write_dsb(display, dsb,
+ PLANE_PRE_CSC_GAMC_DATA(pipe, plane, 0),
+ 1 << 16);
+ } while (i++ < 34);
+ }
+
+ intel_de_write_dsb(display, dsb, PLANE_PRE_CSC_GAMC_INDEX(pipe, plane, 0), 0);
+ }
+}
+
+static void
+xelpd_plane_load_luts(struct intel_dsb *dsb, const struct intel_plane_state *plane_state)
+{
+ if (plane_state->hw.degamma_lut)
+ xelpd_program_plane_pre_csc_lut(dsb, plane_state);
+}
+
static const struct intel_color_funcs chv_color_funcs = {
.color_check = chv_color_check,
.color_commit_arm = i9xx_color_commit_arm,
@@ -4004,6 +4107,7 @@ static const struct intel_color_funcs xelpd_color_funcs = {
.read_csc = icl_read_csc,
.get_config = skl_get_config,
.load_plane_csc_matrix = xelpd_load_plane_csc_matrix,
+ .load_plane_luts = xelpd_plane_load_luts,
};
static const struct intel_color_funcs icl_color_funcs = {
--
2.42.0
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