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

From: Steve Longerbeam
Date: Fri Mar 08 2019 - 20:16:36 EST



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