Re: [PATCH v6 3/7] gpu: ipu-v3: ipu-ic: Fully describe colorspace conversions

Steve Longerbeam <slongerbeam@xxxxxxxxx> · Fri, 8 Mar 2019 17:16:22 -0800

On 3/8/19 3:46 AM, Philipp Zabel wrote:
On Thu, 2019-03-07 at 15:33 -0800, Steve Longerbeam wrote:
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 colorspace (chromaticities), Y'CbCr encoding standard,
and quantization also need to be specified.

Define a 'struct ipu_ic_colorspace' that includes all the above, and pass
the input and output ipu_ic_colorspace to the IC task init functions.

This allows to actually enforce the fact that the IC:

- can only encode to/from YUV full range (follow-up patch will remove
   this restriction).
- can only encode to/from RGB full range.
- can only encode using BT.601 standard (follow-up patch will add
   Rec.709 encoding support).
- cannot convert colorspaces from input to output, the
   input and output colorspace chromaticities must be the same.

The determination of the CSC coefficients based on the input/output
colorspace parameters are moved to a new function calc_csc_coeffs(),
called by init_csc().

Signed-off-by: Steve Longerbeam <slongerbeam@xxxxxxxxx>
---
  drivers/gpu/ipu-v3/ipu-ic.c                 | 136 +++++++++++++-------
  drivers/gpu/ipu-v3/ipu-image-convert.c      |  27 ++--
  drivers/staging/media/imx/imx-ic-prpencvf.c |  22 +++-
  include/video/imx-ipu-v3.h                  |  37 +++++-
  4 files changed, 154 insertions(+), 68 deletions(-)

diff --git a/drivers/gpu/ipu-v3/ipu-ic.c b/drivers/gpu/ipu-v3/ipu-ic.c
index b63a2826b629..c4048c921801 100644
--- a/drivers/gpu/ipu-v3/ipu-ic.c
+++ b/drivers/gpu/ipu-v3/ipu-ic.c
@@ -146,8 +146,10 @@ 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;
@@ -235,42 +237,83 @@ static const struct ic_encode_coeff ic_encode_ycbcr2rgb_601 = {
  	.scale = 2,
  };
  
+static int calc_csc_coeffs(struct ipu_ic_priv *priv,
+			   struct ic_encode_coeff *coeff_out,
+			   const struct ipu_ic_colorspace *in,
+			   const struct ipu_ic_colorspace *out)
+{
+	bool inverse_encode;
+
+	if (in->colorspace != out->colorspace) {
+		dev_err(priv->ipu->dev, "Cannot convert colorspaces\n");
+		return -ENOTSUPP;
+	}
I don't think this is useful enough to warrant having the colorspace
field in ipu_ic_colorspace. Let the caller make sure of this, same as
for xfer_func.

Ok, for xfer_func it is implicit that the gamma function must be the 
same for input and output, so I agree it might as well be implicit for 
chromaticities too.



+	if (out->enc != V4L2_YCBCR_ENC_601) {
+		dev_err(priv->ipu->dev, "Only BT.601 encoding supported\n");
+		return -ENOTSUPP;
+	}
This is only important if out->cs is IPUV3_COLORSPACE_YUV, right? If the
output is RGB this field shouldn't matter.

It matters for encoding YUV to RGB, or the inverse RGB to YUV. The 
encoding standard doesn't matter only if no encoding/inverse encoding is 
requested (YUV to YUV or RGB to RGB).


+
+	if ((in->cs == IPUV3_COLORSPACE_YUV &&
+	     in->quant != V4L2_QUANTIZATION_FULL_RANGE) ||
+	    (out->cs == IPUV3_COLORSPACE_YUV &&
+	     out->quant != V4L2_QUANTIZATION_FULL_RANGE)) {
+		dev_err(priv->ipu->dev, "Limited range YUV not supported\n");
+		return -ENOTSUPP;
+	}
+
+	if ((in->cs == IPUV3_COLORSPACE_RGB &&
+	     in->quant != V4L2_QUANTIZATION_FULL_RANGE) ||
+	    (out->cs == IPUV3_COLORSPACE_RGB &&
+	     out->quant != V4L2_QUANTIZATION_FULL_RANGE)) {
+		dev_err(priv->ipu->dev, "Limited range RGB not supported\n");
+		return -ENOTSUPP;
+	}
+
+	if (in->cs == out->cs) {
+		*coeff_out = ic_encode_identity;
+
+		return 0;
+	}
+
+	inverse_encode = (in->cs == IPUV3_COLORSPACE_YUV);
What does inverse_encode mean in this context?

It means YUV to RGB. At this point in the function it is determined that 
encoding or inverse encoding is requested.


+
+	*coeff_out = inverse_encode ?
+		ic_encode_ycbcr2rgb_601 : ic_encode_rgb2ycbcr_601;
+
+	return 0;
+}
+
  static int init_csc(struct ipu_ic *ic,
-		    enum ipu_color_space inf,
-		    enum ipu_color_space outf,
+		    const struct ipu_ic_colorspace *in,
+		    const struct ipu_ic_colorspace *out,
  		    int csc_index)
  {
  	struct ipu_ic_priv *priv = ic->priv;
-	const struct ic_encode_coeff *coeff;
+	struct ic_encode_coeff coeff;
I understand this is a preparation for patch 5, but on its own this
introduces an unnecessary copy.

True, I'll try to remove the copy in this patch.


  	u32 __iomem *base;
  	const u16 (*c)[3];
  	const u16 *a;
  	u32 param;
+	int ret;
+
+	ret = calc_csc_coeffs(priv, &coeff, in, out);
+	if (ret)
+		return ret;
  
  	base = (u32 __iomem *)
  		(priv->tpmem_base + ic->reg->tpmem_csc[csc_index]);
  
-	if (inf == IPUV3_COLORSPACE_YUV && outf == IPUV3_COLORSPACE_RGB)
-		coeff = &ic_encode_ycbcr2rgb_601;
-	else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_YUV)
-		coeff = &ic_encode_rgb2ycbcr_601;
-	else if (inf == IPUV3_COLORSPACE_RGB && outf == IPUV3_COLORSPACE_RGB)
-		coeff = &ic_encode_identity;
-	else {
-		dev_err(priv->ipu->dev, "Unsupported color space conversion\n");
-		return -EINVAL;
-	}
-
  	/* Cast to unsigned */
-	c = (const u16 (*)[3])coeff->coeff;
-	a = (const u16 *)coeff->offset;
+	c = (const u16 (*)[3])coeff.coeff;
+	a = (const u16 *)coeff.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) | (coeff->scale << 8) |
-		(coeff->sat << 10);
+	param = ((a[0] & 0x1fe0) >> 5) | (coeff.scale << 8) |
+		(coeff.sat << 10);
  	writel(param, base++);
  
  	param = ((a[1] & 0x1f) << 27) | ((c[0][1] & 0x1ff) << 18) |
@@ -357,14 +400,14 @@ 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;
  	}
  
@@ -399,7 +442,7 @@ 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,
What made you decide not to expose the task parameter structure?

I was hoping we could eventually move the V4L2 colorimetry settings to
conversion matrix translation into imx-media.

Sure, I'm fine with that. I'll move the task parameter struct to 
imx-ipu-v3.h.


Btw, do you have any plans for using IC composition?
ipu_ic_task_graphics_init() is currently unused...

No plans for IC composition, I've only been keeping the function 
up-to-date. I've never even tested this, it might not even work. Should 
it be removed?


  			      bool galpha_en, u32 galpha,
  			      bool colorkey_en, u32 colorkey)
  {
@@ -416,20 +459,25 @@ 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)) {
+		struct ipu_ic_colorspace rgb_cs;
+
+		ipu_ic_fill_colorspace(&rgb_cs,
+				       V4L2_COLORSPACE_SRGB,
+				       V4L2_YCBCR_ENC_601,
+				       V4L2_QUANTIZATION_FULL_RANGE,
+				       IPUV3_COLORSPACE_RGB);
+
  		/* need transparent CSC1 conversion */
-		ret = init_csc(ic, IPUV3_COLORSPACE_RGB,
-			       IPUV3_COLORSPACE_RGB, 0);
+		ret = init_csc(ic, &rgb_cs, &rgb_cs, 0);
  		if (ret)
  			goto unlock;
  	}
  
-	ic->g_in_cs = in_g_cs;
+	ic->g_in_cs = *g_in_cs;
  
-	if (ic->g_in_cs != ic->out_cs) {
-		ret = init_csc(ic, ic->g_in_cs, ic->out_cs, 1);
-		if (ret)
-			goto unlock;
-	}
+	ret = init_csc(ic, &ic->g_in_cs, &ic->out_cs, 1);
+	if (ret)
+		goto unlock;
I had to look twice, but this is fine. If ic->g_in_cs == ic->out_cs,
ipu_ic_task_enable() won't enable CSC2 in IC_CONF, and these TPMEM
values will be ignored.

  
  	if (galpha_en) {
  		ic_conf |= IC_CONF_IC_GLB_LOC_A;
@@ -456,10 +504,10 @@ int ipu_ic_task_graphics_init(struct ipu_ic *ic,
  EXPORT_SYMBOL_GPL(ipu_ic_task_graphics_init);
  
  int ipu_ic_task_init_rsc(struct ipu_ic *ic,
+			 const struct ipu_ic_colorspace *in_cs,
+			 const struct ipu_ic_colorspace *out_cs,
  			 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;
@@ -491,28 +539,24 @@ 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 = *in_cs;
+	ic->out_cs = *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, &ic->in_cs, &ic->out_cs, 0);
Same as above for CSC1.
  
-unlock:
  	spin_unlock_irqrestore(&priv->lock, flags);
  	return ret;
  }
  
  int ipu_ic_task_init(struct ipu_ic *ic,
+		     const struct ipu_ic_colorspace *in_cs,
+		     const struct ipu_ic_colorspace *out_cs,
  		     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, in_cs, out_cs,
+				    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 13103ab86050..ccbc8f4d95d7 100644
--- a/drivers/gpu/ipu-v3/ipu-image-convert.c
+++ b/drivers/gpu/ipu-v3/ipu-image-convert.c
@@ -1317,7 +1317,7 @@ 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;
+	struct ipu_ic_colorspace src_cs, dest_cs;
  	unsigned int dst_tile = ctx->out_tile_map[tile];
  	unsigned int dest_width, dest_height;
  	unsigned int col, row;
@@ -1327,8 +1327,16 @@ 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);
+	ipu_ic_fill_colorspace(&src_cs,
+			s_image->base.pix.colorspace,
+			s_image->base.pix.ycbcr_enc,
+			s_image->base.pix.quantization,
+			ipu_pixelformat_to_colorspace(s_image->fmt->fourcc));
+	ipu_ic_fill_colorspace(&dest_cs,
+			d_image->base.pix.colorspace,
+			d_image->base.pix.ycbcr_enc,
+			d_image->base.pix.quantization,
+			ipu_pixelformat_to_colorspace(d_image->fmt->fourcc));
If ipu_ic_task_init(_rsc) could be passed the task parameter structure,
it could be calculated once in ipu_image_convert_prepare and stored in
ipu_image_convert_ctx for repeated use.

Yes, I'll add this for v7.

Steve







