[RFC 09/11] 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    |  6 ++++--
 drivers/gpu/drm/meson/meson_venc.h    | 11 +++++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index fb09592eba3e..2b278ee75100 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -719,7 +719,8 @@ 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,
+				 MESON_VENC_MAP_CB_Y_CR);
 
 	/* 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 c8e9840ad450..ec2723822552 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;
@@ -1496,8 +1498,8 @@ void meson_venc_hdmi_mode_set(struct meson_drm *priv, int vic,
 	writel_relaxed((use_enci ? 1 : 2) |
 		       (mode->flags & DRM_MODE_FLAG_PHSYNC ? 1 << 2 : 0) |
 		       (mode->flags & DRM_MODE_FLAG_PVSYNC ? 1 << 3 : 0) |
-		       4 << 5 |
-		       (venc_repeat ? 1 << 8 : 0) |
+		       (ycrcb_map << 5) |
+		       (venc_repeat || yuv420_mode ? 1 << 8 : 0) |
 		       (hdmi_repeat ? 1 << 12 : 0),
 		       priv->io_base + _REG(VPU_HDMI_SETTING));
 
diff --git a/drivers/gpu/drm/meson/meson_venc.h b/drivers/gpu/drm/meson/meson_venc.h
index 1abdcbdf51c0..88ded5451c49 100644
--- a/drivers/gpu/drm/meson/meson_venc.h
+++ b/drivers/gpu/drm/meson/meson_venc.h
@@ -23,6 +23,15 @@ enum {
 	MESON_VENC_MODE_HDMI,
 };
 
+enum {
+	MESON_VENC_MAP_CR_Y_CB = 0,
+	MESON_VENC_MAP_Y_CB_CR,
+	MESON_VENC_MAP_Y_CR_CB,
+	MESON_VENC_MAP_CB_CR_Y,
+	MESON_VENC_MAP_CB_Y_CR,
+	MESON_VENC_MAP_CR_CB_Y,
+};
+
 struct meson_cvbs_enci_mode {
 	unsigned int mode_tag;
 	unsigned int hso_begin; /* HSO begin position */
@@ -60,6 +69,8 @@ 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