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>

1 files changed, 50 insertions, 6 deletions

diff --git a/include/video/imx-ipu-v3.h b/include/video/imx-ipu-v3.h
index b03fafa1ff58..06b0b57e996c 100644
--- a/include/video/imx-ipu-v3.h
+++ b/include/video/imx-ipu-v3.h
@@ -387,20 +387,64 @@ enum ipu_ic_task {
 	IC_NUM_TASKS,
 };
 
+/*
+ * The parameters that describe a colorspace according to the
+ * Image Converter:
+ *    - Y'CbCr encoding
+ *    - quantization
+ *    - "colorspace" (RGB or YUV).
+ */
+struct ipu_ic_colorspace {
+	enum v4l2_ycbcr_encoding enc;
+	enum v4l2_quantization quant;
+	enum ipu_color_space cs;
+};
+
+static inline void
+ipu_ic_fill_colorspace(struct ipu_ic_colorspace *ic_cs,
+		       enum v4l2_ycbcr_encoding enc,
+		       enum v4l2_quantization quant,
+		       enum ipu_color_space cs)
+{
+	ic_cs->enc = enc;
+	ic_cs->quant = quant;
+	ic_cs->cs = cs;
+}
+
+struct ipu_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)) */
+};
+
+struct ipu_ic_csc {
+	struct ipu_ic_colorspace in_cs;
+	struct ipu_ic_colorspace out_cs;
+	struct ipu_ic_csc_params params;
+};
+
 struct ipu_ic;
+
+int __ipu_ic_calc_csc(struct ipu_ic_csc *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);
 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);
 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);
 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);
 void ipu_ic_task_enable(struct ipu_ic *ic);