[PATCH v7 3/6] drm/i915/dp: Program VSC Header and DB for Pixel Encoding/Colorimetry Format

[Gwan-gyeong Mun]

Function intel_pixel_encoding_setup_vsc handles vsc header and data block
setup for pixel encoding / colorimetry format.

Setup VSC header and data block in function intel_pixel_encoding_setup_vsc
for pixel encoding / colorimetry format as per dp 1.4a spec,
section 2.2.5.7.1, table 2-119: VSC SDP Header Bytes, section 2.2.5.7.5,
table 2-120:VSC SDP Payload for DB16 through DB18.

v2:
  Minor style fix. [Maarten]
  Refer to commit ids instead of patchwork. [Maarten]

v6: Rebase

v7:
  Rebase and addressed review comments from Ville.
  Use a structure initializer instead of memset().
  Fix non-standard comment format.
  Remove a referring to specific commit.
  Add a setting of dynamic range bit to  vsc_sdp.DB17.
  Add a setting of bpc which is based on pipe_bpp.
  Remove duplicated checking of connector's ycbcr_420_allowed from
  intel_pixel_encoding_setup_vsc(). It is already checked from
  intel_dp_ycbcr420_config().
  Remove comments for VSC_SDP_EXTENSION_FOR_COLORIMETRY_SUPPORTED. It is
  already implemented on intel_dp_get_colorimetry_status().

Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c |  1 +
 drivers/gpu/drm/i915/intel_dp.c  | 90 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h |  2 +
 3 files changed, 93 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index cd5277d98b03..2f1688ea5a2c 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -3391,6 +3391,7 @@ static void intel_enable_ddi_dp(struct intel_encoder *encoder,
 
 	intel_edp_backlight_on(crtc_state, conn_state);
 	intel_psr_enable(intel_dp, crtc_state);
+	intel_dp_ycbcr_420_enable(intel_dp, crtc_state);
 	intel_edp_drrs_enable(intel_dp, crtc_state);
 
 	if (crtc_state->has_audio)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 9f219f8f0c71..a3fd279a5c52 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4407,6 +4407,96 @@ u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
 	return 0;
 }
 
+static void
+intel_pixel_encoding_setup_vsc(struct intel_dp *intel_dp,
+			       const struct intel_crtc_state *crtc_state)
+{
+	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
+	struct dp_sdp vsc_sdp = {};
+
+	/* Prepare VSC Header for SU as per DP 1.4a spec, Table 2-119 */
+	vsc_sdp.sdp_header.HB0 = 0;
+	vsc_sdp.sdp_header.HB1 = 0x7;
+
+	/*
+	 * VSC SDP supporting 3D stereo, PSR2, and Pixel Encoding/
+	 * Colorimetry Format indication.
+	 */
+	vsc_sdp.sdp_header.HB2 = 0x5;
+
+	/*
+	 * VSC SDP supporting 3D stereo, + PSR2, + Pixel Encoding/
+	 * Colorimetry Format indication (HB2 = 05h).
+	 */
+	vsc_sdp.sdp_header.HB3 = 0x13;
+
+	/*
+	 * YCbCr 420 = 3h DB16[7:4] ITU-R BT.601 = 0h, ITU-R BT.709 = 1h
+	 * DB16[3:0] DP 1.4a spec, Table 2-120
+	 */
+	vsc_sdp.DB[16] = 0x3 << 4; /* 0x3 << 4 , YCbCr 420*/
+	/* RGB->YCBCR color conversion uses the BT.709 color space. */
+	vsc_sdp.DB[16] |= 0x1; /* 0x1, ITU-R BT.709 */
+
+	/*
+	 * For pixel encoding formats YCbCr444, YCbCr422, YCbCr420, and Y Only,
+	 * the following Component Bit Depth values are defined:
+	 * 001b = 8bpc.
+	 * 010b = 10bpc.
+	 * 011b = 12bpc.
+	 * 100b = 16bpc.
+	 */
+	switch (crtc_state->pipe_bpp) {
+	case 24: /* 8bpc */
+		vsc_sdp.DB[17] = 0x1;
+		break;
+	case 30: /* 10bpc */
+		vsc_sdp.DB[17] = 0x2;
+		break;
+	case 36: /* 12bpc */
+		vsc_sdp.DB[17] = 0x3;
+		break;
+	case 48: /* 16bpc */
+		vsc_sdp.DB[17] = 0x4;
+		break;
+	default:
+		DRM_DEBUG_KMS("Invalid bpp value '%d'\n", crtc_state->pipe_bpp);
+		break;
+	}
+
+	/*
+	 * Dynamic Range (Bit 7)
+	 * 0 = VESA range, 1 = CTA range.
+	 * all YCbCr are always limited range
+	 */
+	vsc_sdp.DB[17] |= 0x80;
+
+	/*
+	 * Content Type (Bits 2:0)
+	 * 000b = Not defined.
+	 * 001b = Graphics.
+	 * 010b = Photo.
+	 * 011b = Video.
+	 * 100b = Game
+	 * All other values are RESERVED.
+	 * Note: See CTA-861-G for the definition and expected
+	 * processing by a stream sink for the above contect types.
+	 */
+	vsc_sdp.DB[18] = 0;
+
+	intel_dig_port->write_infoframe(&intel_dig_port->base,
+			crtc_state, DP_SDP_VSC, &vsc_sdp, sizeof(vsc_sdp));
+}
+
+void intel_dp_ycbcr_420_enable(struct intel_dp *intel_dp,
+			       const struct intel_crtc_state *crtc_state)
+{
+	if (crtc_state->output_format != INTEL_OUTPUT_FORMAT_YCBCR420)
+		return;
+
+	intel_pixel_encoding_setup_vsc(intel_dp, crtc_state);
+}
+
 static u8 intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 {
 	int status = 0;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 247893ed1543..5d1845526cf8 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1576,6 +1576,8 @@ void intel_dp_get_m_n(struct intel_crtc *crtc,
 		      struct intel_crtc_state *pipe_config);
 void intel_dp_set_m_n(const struct intel_crtc_state *crtc_state,
 		      enum link_m_n_set m_n);
+void intel_dp_ycbcr_420_enable(struct intel_dp *intel_dp,
+			       const struct intel_crtc_state *crtc_state);
 int intel_dotclock_calculate(int link_freq, const struct intel_link_m_n *m_n);
 bool bxt_find_best_dpll(struct intel_crtc_state *crtc_state,
 			struct dpll *best_clock);
-- 
2.21.0