MLK-20931: drm/imx/dcss: Add scaler 5 tap filter back for YUV

The following commit:

459a5fac54d - MLK-20263: drm/imx/dcss: fix channel-0 line shift

removed the 5 tap filter for vertical luma/chroma when YUV formats were
used.

Problem is that when the 7 tap filter is used for vertical luma/chroma,
artifacts can be seen on screen when scaling.

RGB can, however, function correctly with only 7 tap filter.

This patch partially reverts the above patch and also does some cosmetic
changes when calling the dcss_scaler_filter_design() using false/true
instead of 0/1 for use_5_taps argument.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>

1 files changed, 61 insertions, 11 deletions

diff --git a/drivers/gpu/imx/dcss/dcss-scaler.c b/drivers/gpu/imx/dcss/dcss-scaler.c
index abddd129169c..051bc4b03f88 100644
--- a/drivers/gpu/imx/dcss/dcss-scaler.c
+++ b/drivers/gpu/imx/dcss/dcss-scaler.c
@@ -657,6 +657,46 @@ bool dcss_scaler_can_scale(struct dcss_soc *dcss, int ch_num,
 }
 EXPORT_SYMBOL(dcss_scaler_can_scale);
 
+static void dcss_scaler_program_5_coef_set(struct dcss_soc *dcss, int ch_num,
+					   int base_addr,
+					   int coef[][PSC_NUM_TAPS])
+{
+	int i, phase;
+
+	for (i = 0; i < PSC_STORED_PHASES; i++) {
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[i][1] & 0xfff) << 16 |
+				   (coef[i][2] & 0xfff) << 4  |
+				   (coef[i][3] & 0xf00) >> 8),
+				  base_addr + i * sizeof(u32));
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[i][3] & 0x0ff) << 20 |
+				   (coef[i][4] & 0xfff) << 8  |
+				   (coef[i][5] & 0xff0) >> 4),
+				  base_addr + 0x40 + i * sizeof(u32));
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[i][5] & 0x00f) << 24),
+				  base_addr + 0x80 + i * sizeof(u32));
+	}
+
+	/* reverse both phase and tap orderings */
+	for (phase = (PSC_NUM_PHASES >> 1) - 1; i < PSC_NUM_PHASES; i++, phase--) {
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[phase][5] & 0xfff) << 16 |
+				   (coef[phase][4] & 0xfff) << 4  |
+				   (coef[phase][3] & 0xf00) >> 8),
+				  base_addr + i * sizeof(u32));
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[phase][3] & 0x0ff) << 20 |
+				   (coef[phase][2] & 0xfff) << 8  |
+				   (coef[phase][1] & 0xff0) >> 4),
+				  base_addr + 0x40 + i * sizeof(u32));
+		dcss_scaler_write(dcss->scaler_priv, ch_num,
+				  ((coef[phase][1] & 0x00f) << 24),
+				  base_addr + 0x80 + i * sizeof(u32));
+	}
+}
+
 static void dcss_scaler_program_7_coef_set(struct dcss_soc *dcss, int ch_num,
 					   int base_addr,
 					   int coef[][PSC_NUM_TAPS])
@@ -710,19 +750,26 @@ static void dcss_scaler_yuv_coef_set(struct dcss_soc *dcss, int ch_num,
 {
 	struct dcss_scaler_ch *ch = &dcss->scaler_priv->ch[ch_num];
 	int coef[PSC_STORED_PHASES][PSC_NUM_TAPS];
+	bool program_5_taps = use_5_taps ||
+			      (dst_format == BUF_FMT_YUV422 &&
+			       src_format == BUF_FMT_ARGB8888_YUV444);
 
 	/* horizontal luma */
-	dcss_scaler_filter_design(src_xres, dst_xres, 0,
+	dcss_scaler_filter_design(src_xres, dst_xres, false,
 				  src_xres == dst_xres, coef);
 	dcss_scaler_program_7_coef_set(dcss, ch_num,
 				       DCSS_SCALER_COEF_HLUM, coef);
 
 	/* vertical luma */
-	dcss_scaler_filter_design(src_yres, dst_yres, use_5_taps,
+	dcss_scaler_filter_design(src_yres, dst_yres, program_5_taps,
 				  src_yres == dst_yres, coef);
 
-	dcss_scaler_program_7_coef_set(dcss, ch_num,
-				       DCSS_SCALER_COEF_VLUM, coef);
+	if (program_5_taps)
+		dcss_scaler_program_5_coef_set(dcss, ch_num,
+					       DCSS_SCALER_COEF_VLUM, coef);
+	else
+		dcss_scaler_program_7_coef_set(dcss, ch_num,
+					       DCSS_SCALER_COEF_VLUM, coef);
 
 	/* adjust chroma resolution */
 	if (src_format != BUF_FMT_ARGB8888_YUV444)
@@ -735,7 +782,7 @@ static void dcss_scaler_yuv_coef_set(struct dcss_soc *dcss, int ch_num,
 		dst_yres >>= 1;
 
 	/* horizontal chroma */
-	dcss_scaler_filter_design(src_xres, dst_xres, 0,
+	dcss_scaler_filter_design(src_xres, dst_xres, false,
 				  (src_xres == dst_xres) && (ch->c_hstart == 0),
 				  coef);
 
@@ -743,12 +790,15 @@ static void dcss_scaler_yuv_coef_set(struct dcss_soc *dcss, int ch_num,
 				       DCSS_SCALER_COEF_HCHR, coef);
 
 	/* vertical chroma */
-	dcss_scaler_filter_design(src_yres, dst_yres, use_5_taps,
+	dcss_scaler_filter_design(src_yres, dst_yres, program_5_taps,
 				  (src_yres == dst_yres) && (ch->c_vstart == 0),
 				  coef);
-
-	dcss_scaler_program_7_coef_set(dcss, ch_num,
-				       DCSS_SCALER_COEF_VCHR, coef);
+	if (program_5_taps)
+		dcss_scaler_program_5_coef_set(dcss, ch_num,
+					       DCSS_SCALER_COEF_VCHR, coef);
+	else
+		dcss_scaler_program_7_coef_set(dcss, ch_num,
+					       DCSS_SCALER_COEF_VCHR, coef);
 }
 
 static void dcss_scaler_rgb_coef_set(struct dcss_soc *dcss, int ch_num,
@@ -758,13 +808,13 @@ static void dcss_scaler_rgb_coef_set(struct dcss_soc *dcss, int ch_num,
 	int coef[PSC_STORED_PHASES][PSC_NUM_TAPS];
 
 	/* horizontal RGB */
-	dcss_scaler_filter_design(src_xres, dst_xres, 0,
+	dcss_scaler_filter_design(src_xres, dst_xres, false,
 				  src_xres == dst_xres, coef);
 	dcss_scaler_program_7_coef_set(dcss, ch_num,
 				       DCSS_SCALER_COEF_HLUM, coef);
 
 	/* vertical RGB */
-	dcss_scaler_filter_design(src_yres, dst_yres, 1,
+	dcss_scaler_filter_design(src_yres, dst_yres, false,
 				  src_yres == dst_yres, coef);
 	dcss_scaler_program_7_coef_set(dcss, ch_num,
 				       DCSS_SCALER_COEF_VLUM, coef);