gpu: ipu-v3: ipu-ic: Fully describe colorspace conversions

Only providing the input and output RGB/YUV space to the IC task init
functions is not sufficient. To fully characterize a colorspace
conversion, the Y'CbCr encoding standard, and quantization also
need to be specified.

Define a 'struct ipu_ic_colorspace' that includes all the above.

This allows to actually enforce the fact that the IC:

- can only encode to/from YUV and RGB full range. A follow-up patch will
  remove this restriction.
- can only encode using BT.601 standard. A follow-up patch will add
  Rec.709 encoding support.

The determination of the CSC coefficients based on the input/output
'struct ipu_ic_colorspace' are moved to a new exported function
ipu_ic_calc_csc(), and 'struct ic_csc_params' is exported as
'struct ipu_ic_csc_params'. ipu_ic_calc_csc() fills a 'struct ipu_ic_csc'
with the input/output 'struct ipu_ic_colorspace' and the calculated
'struct ic_csc_params' from those input/output colorspaces.

The functions ipu_ic_task_init(_rsc)() now take a filled 'struct
ipu_ic_csc'.

The existing CSC coefficient tables and ipu_ic_calc_csc() are moved
to a new module ipu-ic-csc.c. This is in preparation for adding more
coefficient tables for limited range quantization and more encoding
standards.

The existing ycbcr2rgb and inverse rgb2ycbcr tables defined the BT.601
Y'CbCr encoding coefficients. The rgb2ycbcr table specifically described
the BT.601 encoding from full range RGB to full range YUV. Table
comments have been added in ipu-ic-csc.c to make this more clear.

The ycbcr2rgb inverse table described encoding YUV limited range to RGB
full range. To be consistent with the rgb2ycbcr table, this table is
converted to YUV full range to RGB full range, and the comments are
expanded in ipu-ic-csc.c.

The ic_csc_rgb2rgb table was just an identity matrix, so it is renamed
'identity' in ipu-ic-csc.c.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
[p.zabel@pengutronix.de: removed a superfluous blank line]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

4 files changed, 192 insertions, 106 deletions

diff --git a/drivers/gpu/ipu-v3/Makefile b/drivers/gpu/ipu-v3/Makefile
index 7cc8b47e488b..5fe5ef20701a 100644
--- a/drivers/gpu/ipu-v3/Makefile
+++ b/drivers/gpu/ipu-v3/Makefile
@@ -2,8 +2,8 @@
 obj-$(CONFIG_IMX_IPUV3_CORE) += imx-ipu-v3.o
 
 imx-ipu-v3-objs := ipu-common.o ipu-cpmem.o ipu-csi.o ipu-dc.o ipu-di.o \
-		ipu-dp.o ipu-dmfc.o ipu-ic.o ipu-image-convert.o \
-		ipu-smfc.o ipu-vdi.o
+		ipu-dp.o ipu-dmfc.o ipu-ic.o ipu-ic-csc.o \
+		ipu-image-convert.o ipu-smfc.o ipu-vdi.o
 
 ifdef CONFIG_DRM
 	imx-ipu-v3-objs += ipu-pre.o ipu-prg.o
diff --git a/drivers/gpu/ipu-v3/ipu-ic-csc.c b/drivers/gpu/ipu-v3/ipu-ic-csc.c
new file mode 100644
index 000000000000..a5a26fe37608
--- /dev/null
+++ b/drivers/gpu/ipu-v3/ipu-ic-csc.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Mentor Graphics Inc.
+ */
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/sizes.h>
+#include "ipu-prv.h"
+
+/* identity matrix */
+static const struct ipu_ic_csc_params identity = {
+	.coeff = {
+		{  128,    0,    0, },
+		{    0,  128,    0, },
+		{    0,    0,  128, },
+	},
+	.offset = { 0, 0, 0, },
+	.scale = 2,
+};
+
+static const struct ipu_ic_csc_params *rgb2rgb[] = {
+	&identity,
+};
+
+static const struct ipu_ic_csc_params *yuv2yuv[] = {
+	&identity,
+};
+
+/*
+ * BT.601 RGB full-range to YUV full-range
+ *
+ * Y =  .2990 * R + .5870 * G + .1140 * B
+ * U = -.1687 * R - .3313 * G + .5000 * B + 128
+ * V =  .5000 * R - .4187 * G - .0813 * B + 128
+ */
+static const struct ipu_ic_csc_params rgbf2yuvf_601 = {
+	.coeff = {
+		{   77,  150,   29, },
+		{  -43,  -85,  128, },
+		{  128, -107,  -21, },
+	},
+	.offset = { 0, 512, 512, },
+	.scale = 1,
+};
+
+/*
+ * BT.601 YUV full-range to RGB full-range
+ *
+ * R = 1. * Y +      0 * (Cb - 128) + 1.4020 * (Cr - 128)
+ * G = 1. * Y -  .3441 * (Cb - 128) -  .7141 * (Cr - 128)
+ * B = 1. * Y + 1.7720 * (Cb - 128) +      0 * (Cr - 128)
+ *
+ * equivalently (factoring out the offsets):
+ *
+ * R = 1. * Y  +      0 * Cb + 1.4020 * Cr - 179.456
+ * G = 1. * Y  -  .3441 * Cb -  .7141 * Cr + 135.450
+ * B = 1. * Y  + 1.7720 * Cb +      0 * Cr - 226.816
+ */
+static const struct ipu_ic_csc_params yuvf2rgbf_601 = {
+	.coeff = {
+		{  128,    0,  179, },
+		{  128,  -44,  -91, },
+		{  128,  227,    0, },
+	},
+	.offset = { -359, 271, -454, },
+	.scale = 2,
+};
+
+static const struct ipu_ic_csc_params *rgb2yuv_601[] = {
+	&rgbf2yuvf_601,
+};
+
+static const struct ipu_ic_csc_params *yuv2rgb_601[] = {
+	&yuvf2rgbf_601,
+};
+
+static int calc_csc_coeffs(struct ipu_ic_csc *csc)
+{
+	if (csc->out_cs.enc != V4L2_YCBCR_ENC_601)
+		return -ENOTSUPP;
+
+	if ((csc->in_cs.cs == IPUV3_COLORSPACE_YUV &&
+	     csc->in_cs.quant != V4L2_QUANTIZATION_FULL_RANGE) ||
+	    (csc->out_cs.cs == IPUV3_COLORSPACE_YUV &&
+	     csc->out_cs.quant != V4L2_QUANTIZATION_FULL_RANGE))
+		return -ENOTSUPP;
+
+	if ((csc->in_cs.cs == IPUV3_COLORSPACE_RGB &&
+	     csc->in_cs.quant != V4L2_QUANTIZATION_FULL_RANGE) ||
+	    (csc->out_cs.cs == IPUV3_COLORSPACE_RGB &&
+	     csc->out_cs.quant != V4L2_QUANTIZATION_FULL_RANGE))
+		return -ENOTSUPP;
+
+	if (csc->in_cs.cs == csc->out_cs.cs) {
+		csc->params = (csc->in_cs.cs == IPUV3_COLORSPACE_YUV) ?
+			*yuv2yuv[0] : *rgb2rgb[0];
+		return 0;
+	}
+
+	csc->params = (csc->in_cs.cs == IPUV3_COLORSPACE_YUV) ?
+		*yuv2rgb_601[0] : *rgb2yuv_601[0];
+
+	return 0;
+}
+
+int __ipu_ic_calc_csc(struct ipu_ic_csc *csc)
+{
+	return calc_csc_coeffs(csc);
+}
+EXPORT_SYMBOL_GPL(__ipu_ic_calc_csc);
+
+int ipu_ic_calc_csc(struct ipu_ic_csc *csc,
+		    enum v4l2_ycbcr_encoding in_enc,
+		    enum v4l2_quantization in_quant,
+		    enum ipu_color_space in_cs,
+		    enum v4l2_ycbcr_encoding out_enc,
+		    enum v4l2_quantization out_quant,
+		    enum ipu_color_space out_cs)
+{
+	ipu_ic_fill_colorspace(&csc->in_cs, in_enc, in_quant, in_cs);
+	ipu_ic_fill_colorspace(&csc->out_cs, out_enc, out_quant, out_cs);
+
+	return __ipu_ic_calc_csc(csc);
+}
+EXPORT_SYMBOL_GPL(ipu_ic_calc_csc);
diff --git a/drivers/gpu/ipu-v3/ipu-ic.c b/drivers/gpu/ipu-v3/ipu-ic.c
index 3428b0e72bc5..846461bac70d 100644
--- a/drivers/gpu/ipu-v3/ipu-ic.c
+++ b/drivers/gpu/ipu-v3/ipu-ic.c
@@ -140,8 +140,10 @@ struct ipu_ic {
 	const struct ic_task_regoffs *reg;
 	const struct ic_task_bitfields *bit;
 
-	enum ipu_color_space in_cs, g_in_cs;
-	enum ipu_color_space out_cs;
+	struct ipu_ic_colorspace in_cs;
+	struct ipu_ic_colorspace g_in_cs;
+	struct ipu_ic_colorspace out_cs;
+
 	bool graphics;
 	bool rotation;
 	bool in_use;
@@ -169,60 +171,11 @@ static inline void ipu_ic_write(struct ipu_ic *ic, u32 value, unsigned offset)
 	writel(value, ic->priv->base + offset);
 }
 
-struct ic_csc_params {
-	s16 coeff[3][3];	/* signed 9-bit integer coefficients */
-	s16 offset[3];		/* signed 11+2-bit fixed point offset */
-	u8 scale:2;		/* scale coefficients * 2^(scale-1) */
-	bool sat:1;		/* saturate to (16, 235(Y) / 240(U, V)) */
-};
-
-/*
- * Y = R *  .299 + G *  .587 + B *  .114;
- * U = R * -.169 + G * -.332 + B *  .500 + 128.;
- * V = R *  .500 + G * -.419 + B * -.0813 + 128.;
- */
-static const struct ic_csc_params ic_csc_rgb2ycbcr = {
-	.coeff = {
-		{ 77, 150, 29 },
-		{ 469, 427, 128 },
-		{ 128, 405, 491 },
-	},
-	.offset = { 0, 512, 512 },
-	.scale = 1,
-};
-
-/* transparent RGB->RGB matrix for graphics combining */
-static const struct ic_csc_params ic_csc_rgb2rgb = {
-	.coeff = {
-		{ 128, 0, 0 },
-		{ 0, 128, 0 },
-		{ 0, 0, 128 },
-	},
-	.scale = 2,
-};
-
-/*
- * R = (1.164 * (Y - 16)) + (1.596 * (Cr - 128));
- * G = (1.164 * (Y - 16)) - (0.392 * (Cb - 128)) - (0.813 * (Cr - 128));
- * B = (1.164 * (Y - 16)) + (2.017 * (Cb - 128);
- */
-static const struct ic_csc_params ic_csc_ycbcr2rgb = {
-	.coeff = {
-		{ 149, 0, 204 },
-		{ 149, 462, 408 },
-		{ 149, 255, 0 },
-	},
-	.offset = { -446, 266, -554 },
-	.scale = 2,
-};
-
 static int init_csc(struct ipu_ic *ic,
-		    enum ipu_color_space inf,
-		    enum ipu_color_space outf,
+		    const struct ipu_ic_csc *csc,
 		    int csc_index)
 {
 	struct ipu_ic_priv *priv = ic->priv;
-	const struct ic_csc_params *params;
 	u32 __iomem *base;
 	const u16 (*c)[3];
 	const u16 *a;
@@ -231,27 +184,16 @@ static int init_csc(struct ipu_ic *ic,
 	base = (u32 __iomem *)
 		(priv->tpmem_base + ic->reg->tpmem_csc[csc_index]);
 
-	if (inf == IPUV3_COLORSPACE_YUV && outf == IPUV3_COLORSPACE_RGB)
-		params = &ic_csc_ycbcr2rgb;
-	else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_YUV)
-		params = &ic_csc_rgb2ycbcr;
-	else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_RGB)
-		params = &ic_csc_rgb2rgb;
-	else {
-		dev_err(priv->ipu->dev, "Unsupported color space conversion\n");
-		return -EINVAL;
-	}
-
 	/* Cast to unsigned */
-	c = (const u16 (*)[3])params->coeff;
-	a = (const u16 *)params->offset;
+	c = (const u16 (*)[3])csc->params.coeff;
+	a = (const u16 *)csc->params.offset;
 
 	param = ((a[0] & 0x1f) << 27) | ((c[0][0] & 0x1ff) << 18) |
 		((c[1][1] & 0x1ff) << 9) | (c[2][2] & 0x1ff);
 	writel(param, base++);
 
-	param = ((a[0] & 0x1fe0) >> 5) | (params->scale << 8) |
-		(params->sat << 10);
+	param = ((a[0] & 0x1fe0) >> 5) | (csc->params.scale << 8) |
+		(csc->params.sat << 10);
 	writel(param, base++);
 
 	param = ((a[1] & 0x1f) << 27) | ((c[0][1] & 0x1ff) << 18) |
@@ -338,14 +280,14 @@ void ipu_ic_task_enable(struct ipu_ic *ic)
 	if (ic->rotation)
 		ic_conf |= ic->bit->ic_conf_rot_en;
 
-	if (ic->in_cs != ic->out_cs)
+	if (ic->in_cs.cs != ic->out_cs.cs)
 		ic_conf |= ic->bit->ic_conf_csc1_en;
 
 	if (ic->graphics) {
 		ic_conf |= ic->bit->ic_conf_cmb_en;
 		ic_conf |= ic->bit->ic_conf_csc1_en;
 
-		if (ic->g_in_cs != ic->out_cs)
+		if (ic->g_in_cs.cs != ic->out_cs.cs)
 			ic_conf |= ic->bit->ic_conf_csc2_en;
 	}
 
@@ -380,11 +322,12 @@ void ipu_ic_task_disable(struct ipu_ic *ic)
 EXPORT_SYMBOL_GPL(ipu_ic_task_disable);
 
 int ipu_ic_task_graphics_init(struct ipu_ic *ic,
-			      enum ipu_color_space in_g_cs,
+			      const struct ipu_ic_colorspace *g_in_cs,
 			      bool galpha_en, u32 galpha,
 			      bool colorkey_en, u32 colorkey)
 {
 	struct ipu_ic_priv *priv = ic->priv;
+	struct ipu_ic_csc csc2;
 	unsigned long flags;
 	u32 reg, ic_conf;
 	int ret = 0;
@@ -397,21 +340,36 @@ int ipu_ic_task_graphics_init(struct ipu_ic *ic,
 	ic_conf = ipu_ic_read(ic, IC_CONF);
 
 	if (!(ic_conf & ic->bit->ic_conf_csc1_en)) {
-		/* need transparent CSC1 conversion */
-		ret = init_csc(ic, IPUV3_COLORSPACE_RGB,
-			       IPUV3_COLORSPACE_RGB, 0);
+		struct ipu_ic_csc csc1;
+
+		ret = ipu_ic_calc_csc(&csc1,
+				      V4L2_YCBCR_ENC_601,
+				      V4L2_QUANTIZATION_FULL_RANGE,
+				      IPUV3_COLORSPACE_RGB,
+				      V4L2_YCBCR_ENC_601,
+				      V4L2_QUANTIZATION_FULL_RANGE,
+				      IPUV3_COLORSPACE_RGB);
 		if (ret)
 			goto unlock;
-	}
-
-	ic->g_in_cs = in_g_cs;
 
-	if (ic->g_in_cs != ic->out_cs) {
-		ret = init_csc(ic, ic->g_in_cs, ic->out_cs, 1);
+		/* need transparent CSC1 conversion */
+		ret = init_csc(ic, &csc1, 0);
 		if (ret)
 			goto unlock;
 	}
 
+	ic->g_in_cs = *g_in_cs;
+	csc2.in_cs = ic->g_in_cs;
+	csc2.out_cs = ic->out_cs;
+
+	ret = __ipu_ic_calc_csc(&csc2);
+	if (ret)
+		goto unlock;
+
+	ret = init_csc(ic, &csc2, 1);
+	if (ret)
+		goto unlock;
+
 	if (galpha_en) {
 		ic_conf |= IC_CONF_IC_GLB_LOC_A;
 		reg = ipu_ic_read(ic, IC_CMBP_1);
@@ -437,10 +395,9 @@ unlock:
 EXPORT_SYMBOL_GPL(ipu_ic_task_graphics_init);
 
 int ipu_ic_task_init_rsc(struct ipu_ic *ic,
+			 const struct ipu_ic_csc *csc,
 			 int in_width, int in_height,
 			 int out_width, int out_height,
-			 enum ipu_color_space in_cs,
-			 enum ipu_color_space out_cs,
 			 u32 rsc)
 {
 	struct ipu_ic_priv *priv = ic->priv;
@@ -472,28 +429,23 @@ int ipu_ic_task_init_rsc(struct ipu_ic *ic,
 	ipu_ic_write(ic, rsc, ic->reg->rsc);
 
 	/* Setup color space conversion */
-	ic->in_cs = in_cs;
-	ic->out_cs = out_cs;
+	ic->in_cs = csc->in_cs;
+	ic->out_cs = csc->out_cs;
 
-	if (ic->in_cs != ic->out_cs) {
-		ret = init_csc(ic, ic->in_cs, ic->out_cs, 0);
-		if (ret)
-			goto unlock;
-	}
+	ret = init_csc(ic, csc, 0);
 
-unlock:
 	spin_unlock_irqrestore(&priv->lock, flags);
 	return ret;
 }
 
 int ipu_ic_task_init(struct ipu_ic *ic,
+		     const struct ipu_ic_csc *csc,
 		     int in_width, int in_height,
-		     int out_width, int out_height,
-		     enum ipu_color_space in_cs,
-		     enum ipu_color_space out_cs)
+		     int out_width, int out_height)
 {
-	return ipu_ic_task_init_rsc(ic, in_width, in_height, out_width,
-				    out_height, in_cs, out_cs, 0);
+	return ipu_ic_task_init_rsc(ic, csc,
+				    in_width, in_height,
+				    out_width, out_height, 0);
 }
 EXPORT_SYMBOL_GPL(ipu_ic_task_init);
 
diff --git a/drivers/gpu/ipu-v3/ipu-image-convert.c b/drivers/gpu/ipu-v3/ipu-image-convert.c
index 36e88434513a..d2457fde25fa 100644
--- a/drivers/gpu/ipu-v3/ipu-image-convert.c
+++ b/drivers/gpu/ipu-v3/ipu-image-convert.c
@@ -146,6 +146,7 @@ struct ipu_image_convert_ctx {
 	/* Source/destination image data and rotation mode */
 	struct ipu_image_convert_image in;
 	struct ipu_image_convert_image out;
+	struct ipu_ic_csc csc;
 	enum ipu_rotate_mode rot_mode;
 	u32 downsize_coeff_h;
 	u32 downsize_coeff_v;
@@ -1308,7 +1309,6 @@ static int convert_start(struct ipu_image_convert_run *run, unsigned int tile)
 	struct ipu_image_convert_priv *priv = chan->priv;
 	struct ipu_image_convert_image *s_image = &ctx->in;
 	struct ipu_image_convert_image *d_image = &ctx->out;
-	enum ipu_color_space src_cs, dest_cs;
 	unsigned int dst_tile = ctx->out_tile_map[tile];
 	unsigned int dest_width, dest_height;
 	unsigned int col, row;
@@ -1318,9 +1318,6 @@ static int convert_start(struct ipu_image_convert_run *run, unsigned int tile)
 	dev_dbg(priv->ipu->dev, "%s: task %u: starting ctx %p run %p tile %u -> %u\n",
 		__func__, chan->ic_task, ctx, run, tile, dst_tile);
 
-	src_cs = ipu_pixelformat_to_colorspace(s_image->fmt->fourcc);
-	dest_cs = ipu_pixelformat_to_colorspace(d_image->fmt->fourcc);
-
 	if (ipu_rot_mode_is_irt(ctx->rot_mode)) {
 		/* swap width/height for resizer */
 		dest_width = d_image->tile[dst_tile].height;
@@ -1343,13 +1340,12 @@ static int convert_start(struct ipu_image_convert_run *run, unsigned int tile)
 		s_image->tile[tile].height, dest_width, dest_height, rsc);
 
 	/* setup the IC resizer and CSC */
-	ret = ipu_ic_task_init_rsc(chan->ic,
-			       s_image->tile[tile].width,
-			       s_image->tile[tile].height,
-			       dest_width,
-			       dest_height,
-			       src_cs, dest_cs,
-			       rsc);
+	ret = ipu_ic_task_init_rsc(chan->ic, &ctx->csc,
+				   s_image->tile[tile].width,
+				   s_image->tile[tile].height,
+				   dest_width,
+				   dest_height,
+				   rsc);
 	if (ret) {
 		dev_err(priv->ipu->dev, "ipu_ic_task_init failed, %d\n", ret);
 		return ret;
@@ -2049,6 +2045,16 @@ ipu_image_convert_prepare(struct ipu_soc *ipu, enum ipu_ic_task ic_task,
 
 	calc_tile_resize_coefficients(ctx);
 
+	ret = ipu_ic_calc_csc(&ctx->csc,
+			s_image->base.pix.ycbcr_enc,
+			s_image->base.pix.quantization,
+			ipu_pixelformat_to_colorspace(s_image->fmt->fourcc),
+			d_image->base.pix.ycbcr_enc,
+			d_image->base.pix.quantization,
+			ipu_pixelformat_to_colorspace(d_image->fmt->fourcc));
+	if (ret)
+		goto out_free;
+
 	dump_format(ctx, s_image);
 	dump_format(ctx, d_image);