[PATCH RFC v2 6/8] drm/meson: venc: add support for YUV420 setup

[Neil Armstrong <narmstrong@baylibre.com>]

This patch adds encoding support for the YUV420 output from the
Amlogic Meson SoCs Video Processing Unit to the HDMI Controller.

The YUV420 is obtained by generating a YUV444 pixel stream like
the classic HDMI display modes, but then the Video Encoder output
can be configured to down-sample the YUV444 pixel stream to a YUV420
stream.

In addition if pixel stream down-sampling, the Y Cb Cr components must
also be mapped differently to align with the HDMI2.0 specifications.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 3 ++-
 drivers/gpu/drm/meson/meson_venc.c    | 8 +++++---
 drivers/gpu/drm/meson/meson_venc.h    | 2 ++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 9ae24cc5faa2..2c69024e5bcf 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -758,7 +758,8 @@ static void meson_venc_hdmi_encoder_mode_set(struct drm_bridge *bridge,
 	DRM_DEBUG_DRIVER("\"%s\" vic %d\n", mode->name, vic);
 
 	/* VENC + VENC-DVI Mode setup */
-	meson_venc_hdmi_mode_set(priv, vic, mode);
+	meson_venc_hdmi_mode_set(priv, vic, ycrcb_map, false,
+				 VPU_HDMI_OUTPUT_CBYCR);
 
 	/* VCLK Set clock */
 	dw_hdmi_set_vclk(dw_hdmi, mode);
diff --git a/drivers/gpu/drm/meson/meson_venc.c b/drivers/gpu/drm/meson/meson_venc.c
index d2d4c3ebf46b..be1fb08a80f5 100644
--- a/drivers/gpu/drm/meson/meson_venc.c
+++ b/drivers/gpu/drm/meson/meson_venc.c
@@ -946,6 +946,8 @@ bool meson_venc_hdmi_venc_repeat(int vic)
 EXPORT_SYMBOL_GPL(meson_venc_hdmi_venc_repeat);
 
 void meson_venc_hdmi_mode_set(struct meson_drm *priv, int vic,
+			      unsigned int ycrcb_map,
+			      bool yuv420_mode,
 			      const struct drm_display_mode *mode)
 {
 	union meson_hdmi_venc_mode *vmode = NULL;
@@ -1528,14 +1530,14 @@ void meson_venc_hdmi_mode_set(struct meson_drm *priv, int vic,
 	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
 		reg |= VPU_HDMI_INV_VSYNC;
 
-	/* Output data format: CbYCr */
-	reg |= VPU_HDMI_OUTPUT_CBYCR;
+	/* Output data format */
+	reg |= ycrcb_map;
 
 	/*
 	 * Write rate to the async FIFO between VENC and HDMI.
 	 * One write every 2 wr_clk.
 	 */
-	if (venc_repeat)
+	if (venc_repeat || yuv420_mode)
 		reg |= VPU_HDMI_WR_RATE(2);
 
 	/*
diff --git a/drivers/gpu/drm/meson/meson_venc.h b/drivers/gpu/drm/meson/meson_venc.h
index 1abdcbdf51c0..9138255ffc9e 100644
--- a/drivers/gpu/drm/meson/meson_venc.h
+++ b/drivers/gpu/drm/meson/meson_venc.h
@@ -60,6 +60,8 @@ extern struct meson_cvbs_enci_mode meson_cvbs_enci_ntsc;
 void meson_venci_cvbs_mode_set(struct meson_drm *priv,
 			       struct meson_cvbs_enci_mode *mode);
 void meson_venc_hdmi_mode_set(struct meson_drm *priv, int vic,
+			      unsigned int ycrcb_map,
+			      bool yuv420_mode,
 			      const struct drm_display_mode *mode);
 unsigned int meson_venci_get_field(struct meson_drm *priv);
 
-- 
2.22.0