drm/meson: Support Overlay plane for video rendering

The Amlogic Meson GX SoCs support an Overlay plane behind the primary
plane for video rendering.

This Overlay plane support various YUV layouts :
- YUYV
- NV12 / NV21
- YUV444 / 422 / 420 / 411 / 410

The scaler supports a wide range of scaling ratios, but for simplicity,
plane atomic check limits the scaling from x5 to /5 in vertical and
horizontal scaling.

The z-order is fixed and always behind the primary plane and cannot be changed.

The scaling parameter algorithm was taken from the Amlogic vendor kernel
code and rewritten to match the atomic universal plane requirements.

The video rendering using this overlay plane support has been tested using
the new Kodi DRM-KMS Prime rendering path along the in-review V4L2 Mem2Mem
Hardware Video Decoder up to 3840x2160 NV12 frames on various display modes.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Maxime Jourdan <mjourdan@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1541497202-20570-2-git-send-email-narmstrong@baylibre.com

1 files changed, 43 insertions, 1 deletions

diff --git a/drivers/gpu/drm/meson/meson_vpp.c b/drivers/gpu/drm/meson/meson_vpp.c
index 27356f81a0ab..5dc24a99e978 100644
--- a/drivers/gpu/drm/meson/meson_vpp.c
+++ b/drivers/gpu/drm/meson/meson_vpp.c
@@ -122,6 +122,31 @@ static void meson_vpp_write_scaling_filter_coefs(struct meson_drm *priv,
 				priv->io_base + _REG(VPP_OSD_SCALE_COEF));
 }
 
+static const uint32_t vpp_filter_coefs_bicubic[] = {
+	0x00800000, 0x007f0100, 0xff7f0200, 0xfe7f0300,
+	0xfd7e0500, 0xfc7e0600, 0xfb7d0800, 0xfb7c0900,
+	0xfa7b0b00, 0xfa7a0dff, 0xf9790fff, 0xf97711ff,
+	0xf87613ff, 0xf87416fe, 0xf87218fe, 0xf8701afe,
+	0xf76f1dfd, 0xf76d1ffd, 0xf76b21fd, 0xf76824fd,
+	0xf76627fc, 0xf76429fc, 0xf7612cfc, 0xf75f2ffb,
+	0xf75d31fb, 0xf75a34fb, 0xf75837fa, 0xf7553afa,
+	0xf8523cfa, 0xf8503ff9, 0xf84d42f9, 0xf84a45f9,
+	0xf84848f8
+};
+
+static void meson_vpp_write_vd_scaling_filter_coefs(struct meson_drm *priv,
+						    const unsigned int *coefs,
+						    bool is_horizontal)
+{
+	int i;
+
+	writel_relaxed(is_horizontal ? BIT(8) : 0,
+			priv->io_base + _REG(VPP_SCALE_COEF_IDX));
+	for (i = 0; i < 33; i++)
+		writel_relaxed(coefs[i],
+				priv->io_base + _REG(VPP_SCALE_COEF));
+}
+
 void meson_vpp_init(struct meson_drm *priv)
 {
 	/* set dummy data default YUV black */
@@ -150,17 +175,34 @@ void meson_vpp_init(struct meson_drm *priv)
 
 	/* Force all planes off */
 	writel_bits_relaxed(VPP_OSD1_POSTBLEND | VPP_OSD2_POSTBLEND |
-			    VPP_VD1_POSTBLEND | VPP_VD2_POSTBLEND, 0,
+			    VPP_VD1_POSTBLEND | VPP_VD2_POSTBLEND |
+			    VPP_VD1_PREBLEND | VPP_VD2_PREBLEND, 0,
 			    priv->io_base + _REG(VPP_MISC));
 
+	/* Setup default VD settings */
+	writel_relaxed(4096,
+			priv->io_base + _REG(VPP_PREBLEND_VD1_H_START_END));
+	writel_relaxed(4096,
+			priv->io_base + _REG(VPP_BLEND_VD2_H_START_END));
+
 	/* Disable Scalers */
 	writel_relaxed(0, priv->io_base + _REG(VPP_OSD_SC_CTRL0));
 	writel_relaxed(0, priv->io_base + _REG(VPP_OSD_VSC_CTRL0));
 	writel_relaxed(0, priv->io_base + _REG(VPP_OSD_HSC_CTRL0));
+	writel_relaxed(4 | (4 << 8) | BIT(15),
+		       priv->io_base + _REG(VPP_SC_MISC));
+
+	writel_relaxed(1, priv->io_base + _REG(VPP_VADJ_CTRL));
 
 	/* Write in the proper filter coefficients. */
 	meson_vpp_write_scaling_filter_coefs(priv,
 				vpp_filter_coefs_4point_bspline, false);
 	meson_vpp_write_scaling_filter_coefs(priv,
 				vpp_filter_coefs_4point_bspline, true);
+
+	/* Write the VD proper filter coefficients. */
+	meson_vpp_write_vd_scaling_filter_coefs(priv, vpp_filter_coefs_bicubic,
+						false);
+	meson_vpp_write_vd_scaling_filter_coefs(priv, vpp_filter_coefs_bicubic,
+						true);
 }