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From:   Mihail Atanassov <Mihail.Atanassov@arm.com>
To:     "james qian wang (Arm Technology China)" <james.qian.wang@arm.com>
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        Ayan Halder <Ayan.Halder@arm.com>,
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        "Yiqi Kang (Arm Technology China)" <Yiqi.Kang@arm.com>,
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Subject: Re: [PATCH v2 2/4] drm/komeda: Introduce komeda_color_manager/state
Thread-Topic: [PATCH v2 2/4] drm/komeda: Introduce komeda_color_manager/state
Thread-Index: AQHVUZN2ECag5jvL6k2i3zNMwO/wrKb45t6AgAFgXgCAADD+gA==
Date:   Wed, 14 Aug 2019 10:47:40 +0000
Message-ID: <1949712.9lhcy9HeBp@e123338-lin>
References: <20190813045536.28239-1-james.qian.wang@arm.com>
 <3902025.BCtzpz6JhW@e123338-lin> <20190814075210.GA24984@jamwan02-TSP300>
In-Reply-To: <20190814075210.GA24984@jamwan02-TSP300>
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On Wednesday, 14 August 2019 08:52:18 BST james qian wang (Arm Technology C=
hina) wrote:
> On Tue, Aug 13, 2019 at 09:51:08AM +0000, Mihail Atanassov wrote:
> > Hi James,
> >=20
> > On Tuesday, 13 August 2019 05:56:07 BST james qian wang (Arm Technology=
 China) wrote:
> > > Many komeda component support color management like layer and IPS, so
> > > komeda_color_manager/state are introduced to manager gamma, csc and d=
egamma
> > > together for easily share it to multiple componpent.
> > >=20
> > > And for komeda_color_manager which:
> > > - convert drm 3d gamma lut to komeda specific gamma coeffs
> > > - gamma table management and hide the HW difference for komeda-CORE
> > >=20
> > > Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wan=
g@arm.com>
> > > ---
> > >  .../arm/display/komeda/komeda_color_mgmt.c    | 126 ++++++++++++++++=
++
> > >  .../arm/display/komeda/komeda_color_mgmt.h    |  32 ++++-
> > >  2 files changed, 156 insertions(+), 2 deletions(-)
> > >=20
> > > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c b=
/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> > > index 9d14a92dbb17..bf2388d641b9 100644
> > > --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> > > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> > > @@ -4,7 +4,9 @@
> > >   * Author: James.Qian.Wang <james.qian.wang@arm.com>
> > >   *
> > >   */
> > > +#include <drm/drm_print.h>
> > > =20
> > > +#include "malidp_utils.h"
> > >  #include "komeda_color_mgmt.h"
> > > =20
> > >  /* 10bit precision YUV2RGB matrix */
> > > @@ -65,3 +67,127 @@ const s32 *komeda_select_yuv2rgb_coeffs(u32 color=
_encoding, u32 color_range)
> > > =20
> > >  	return coeffs;
> > >  }
> > > +
> > > +struct gamma_curve_sector {
> > > +	u32 boundary_start;
> > > +	u32 num_of_segments;
> > > +	u32 segment_width;
> > > +};
> > > +
> > > +struct gamma_curve_segment {
> > > +	u32 start;
> > > +	u32 end;
> > > +};
> > > +
> > > +static struct gamma_curve_sector sector_tbl[] =3D {
> > > +	{ 0,    4,  4   },
Max LUT precision (see full response below) is determined by your
smallest segment, which is 4.
> > > +	{ 16,   4,  4   },
> > > +	{ 32,   4,  8   },
> > > +	{ 64,   4,  16  },
> > > +	{ 128,  4,  32  },
> > > +	{ 256,  4,  64  },
> > > +	{ 512,  16, 32  },
> > > +	{ 1024, 24, 128 },
> > > +};
> > > +
> > > +static struct gamma_curve_sector igamma_sector_tbl[] =3D {
> > > +	{0, 64, 64},
> > > +};
> > > +
> > > +static void
> > > +drm_lut_to_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs,
> > > +		  struct gamma_curve_sector *sector_tbl, u32 num_sectors)
> > > +{
> > > +	struct drm_color_lut *lut;
> > > +	u32 i, j, in, num =3D 0;
> > > +
> > > +	if (!lut_blob)
> > > +		return;
> > > +
> > > +	lut =3D lut_blob->data;
> > > +
> > > +	for (i =3D 0; i < num_sectors; i++) {
> > > +		for (j =3D 0; j < sector_tbl[i].num_of_segments; j++) {
> > > +			in =3D sector_tbl[i].boundary_start +
> > > +			     j * sector_tbl[i].segment_width;
> > > +
> > > +			coeffs[num++] =3D drm_color_lut_extract(lut[in].red,
> > > +						KOMEDA_COLOR_PRECISION);
> > > +		}
> > > +	}
> > > +
> > > +	coeffs[num] =3D BIT(KOMEDA_COLOR_PRECISION);
> > > +}
> > > +
> > > +void drm_lut_to_igamma_coeffs(struct drm_property_blob *lut_blob, u3=
2 *coeffs)
> > > +{
> > > +	drm_lut_to_coeffs(lut_blob, coeffs,
> > > +			  igamma_sector_tbl, ARRAY_SIZE(igamma_sector_tbl));
> > > +}
> > > +
> > > +void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u3=
2 *coeffs)
> > > +{
> > > +	drm_lut_to_coeffs(lut_blob, coeffs,
> > > +			  sector_tbl, ARRAY_SIZE(sector_tbl));
> > > +}
> > > +
> > > +void drm_ctm_to_coeffs(struct drm_property_blob *ctm_blob, u32 *coef=
fs)
> > > +{
> > > +	struct drm_color_ctm *ctm;
> > > +	u32 i;
> > > +
> > > +	if (!ctm_blob)
> > > +		return;
> > > +
> > > +	ctm =3D ctm_blob->data;
> > > +
> > > +	for (i =3D 0; i < KOMEDA_N_CTM_COEFFS; ++i) {
> > > +		/* Convert from S31.32 to Q3.12. */
> > > +		s64 v =3D ctm->matrix[i];
> > > +
> > > +		coeffs[i] =3D clamp_val(v, 1 - (1LL << 34), (1LL << 34) - 1) >> 20=
;
> > CTM matrix values are S31.32, i.e. sign-magnitude, so clamp_val won't
> > give you the right result for negative coeffs. See
> > malidp_crtc_atomic_check_ctm for the sign-mag -> 2's complement
> > conversion.
>=20
> Thank you Mihail for pointing this out.
>=20
> No matter our user or kernel all assume this s31.32 as 2's complement.=20
> we need to correct them both.
>=20
> > > +	}
> > > +}
> > > +
> > > +void komeda_color_duplicate_state(struct komeda_color_state *new,
> > > +				  struct komeda_color_state *old)
> > [bikeshed] not really a _duplicate_state if all it does is refcounts.
> > kmemdup here and return a pointer (with ERR_PTR on fail), or memcpy if
> > you want to keep the signature?
>=20
> Yes, the dup mostly should return a new ptr from a old, the dup name here
> is not accurate.
> the reason is the color_state is not a separated structure but always
> embedded into layer_state, but I want to make all color_state operation
> into a func.
> Do you have any suggestion ?
>=20
After looking at the follow-up patch, not really (at least not any
good ones). I did tag it with [bikeshed] after all, it's not that
big a deal.

> > > +{
> > > +	new->igamma =3D komeda_coeffs_get(old->igamma);
> > > +	new->fgamma =3D komeda_coeffs_get(old->fgamma);
> > > +}
> > > +
> > > +void komeda_color_cleanup_state(struct komeda_color_state *color_st)
> > > +{
> > > +	komeda_coeffs_put(color_st->igamma);
> > > +	komeda_coeffs_put(color_st->fgamma);
> > > +}
> > > +
> > > +int komeda_color_validate(struct komeda_color_manager *mgr,
> > > +			  struct komeda_color_state *st,
> > > +			  struct drm_property_blob *igamma_blob,
> > > +			  struct drm_property_blob *fgamma_blob)
> > > +{
> > > +	u32 coeffs[KOMEDA_N_GAMMA_COEFFS];
> > > +
> > > +	komeda_color_cleanup_state(st);
> > > +
> > > +	if (igamma_blob) {
> > > +		drm_lut_to_igamma_coeffs(igamma_blob, coeffs);
> > > +		st->igamma =3D komeda_coeffs_request(mgr->igamma_mgr, coeffs);
> > > +		if (!st->igamma) {
> > > +			DRM_DEBUG_ATOMIC("request igamma table failed.\n");
> > > +			return -EBUSY;
> > > +		}
> > > +	}
> > > +
> > > +	if (fgamma_blob) {
> > > +		drm_lut_to_fgamma_coeffs(fgamma_blob, coeffs);
> > > +		st->fgamma =3D komeda_coeffs_request(mgr->fgamma_mgr, coeffs);
> > > +		if (!st->fgamma) {
> > > +			DRM_DEBUG_ATOMIC("request fgamma table failed.\n");
> > > +			return -EBUSY;
> > > +		}
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h b=
/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> > > index a2df218f58e7..41a96b3b540f 100644
> > > --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> > > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> > > @@ -4,14 +4,42 @@
> > >   * Author: James.Qian.Wang <james.qian.wang@arm.com>
> > >   *
> > >   */
> > > -
> > >  #ifndef _KOMEDA_COLOR_MGMT_H_
> > >  #define _KOMEDA_COLOR_MGMT_H_
> > > =20
> > >  #include <drm/drm_color_mgmt.h>
> > > +#include "komeda_coeffs.h"
> > > =20
> > >  #define KOMEDA_N_YUV2RGB_COEFFS		12
> > > +#define KOMEDA_N_RGB2YUV_COEFFS		12
> > > +#define KOMEDA_COLOR_PRECISION		12
> > > +#define KOMEDA_N_GAMMA_COEFFS		65
> > > +#define KOMEDA_COLOR_LUT_SIZE		BIT(KOMEDA_COLOR_PRECISION)
>=20
> > I don't see how the number of LUT entries has anything to do with the
> > bit-precision of each entry.
>=20
> Because our komeda color is 12-bit precison, and for 1 vs 1 loopup
> table, we need BIT(12) entries.
>=20
> Thank you
> James
>=20
But your maximum possible precision in HW is 4 times less. You only
really need one LUT entry per segment (its start) in order to
define it (and the slope, but you get the idea). I.e. at your current
4K-sized LUT table, the conversion to the internal representation only
_really_ needs to access offsets 0, 4, etc. and even less often as
it goes. If you make your table 1K entries instead, you save yourself
24KiB every time the (i)gamma changes.

TL;DR: you don't need 1:1 lookup, you need a lossless conversion from
the LUT to the HW format.

> > > +#define KOMEDA_N_CTM_COEFFS		9
> > > +
> > > +struct komeda_color_manager {
> > > +	struct komeda_coeffs_manager *igamma_mgr;
> > > +	struct komeda_coeffs_manager *fgamma_mgr;
> > > +	bool has_ctm;
> > > +};
> > > +
> > > +struct komeda_color_state {
> > > +	struct komeda_coeffs_table *igamma;
> > > +	struct komeda_coeffs_table *fgamma;
> > > +};
> > > +
> > > +void komeda_color_duplicate_state(struct komeda_color_state *new,
> > > +				  struct komeda_color_state *old);
> > > +void komeda_color_cleanup_state(struct komeda_color_state *color_st)=
;
> > > +int komeda_color_validate(struct komeda_color_manager *mgr,
> > > +			  struct komeda_color_state *st,
> > > +			  struct drm_property_blob *igamma_blob,
> > > +			  struct drm_property_blob *fgamma_blob);
> > > +
> > > +void drm_lut_to_igamma_coeffs(struct drm_property_blob *lut_blob, u3=
2 *coeffs);
> > > +void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u3=
2 *coeffs);
> > > +void drm_ctm_to_coeffs(struct drm_property_blob *ctm_blob, u32 *coef=
fs);
> > > =20
> > >  const s32 *komeda_select_yuv2rgb_coeffs(u32 color_encoding, u32 colo=
r_range);
> > > =20
> > > -#endif
> > > +#endif /*_KOMEDA_COLOR_MGMT_H_*/
> > >=20
> >=20
> > BR,
> > Mihail
> >=20
> >=20
>=20

BR,
Mihail