[libcamera-devel] [PATCH v2 03/12] ipa: ipu3: Change Accumulator structure layout

[Laurent Pinchart]

Hi Jean-Michel,

On Tue, Oct 05, 2021 at 07:34:33AM +0200, Jean-Michel Hautbois wrote:
> On 05/10/2021 03:01, Laurent Pinchart wrote:
> > On Thu, Sep 30, 2021 at 11:37:06AM +0200, Jean-Michel Hautbois wrote:
> >> The pixel component sums for the Accumulator are inconsistent with other
> >> similar structures such as the IPAFrameContext::awb::gains. Group the
> >> red, green, and blue sums together in a struct and store them as
> >> uint64_t to reduce potential architectural differences.
> >>
> >> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> >> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> >> ---
> >>  src/ipa/ipu3/algorithms/awb.cpp | 24 ++++++++++++------------
> >>  src/ipa/ipu3/algorithms/awb.h   |  8 +++++---
> >>  2 files changed, 17 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
> >> index fd2f12ca..5f61cb89 100644
> >> --- a/src/ipa/ipu3/algorithms/awb.cpp
> >> +++ b/src/ipa/ipu3/algorithms/awb.cpp
> >> @@ -75,13 +75,13 @@ static constexpr uint32_t kMinGreenLevelInZone = 32;
> >>   * \var Accumulator::counted
> >>   * \brief Number of unsaturated cells used to calculate the sums
> >>   *
> >> - * \var Accumulator::rSum
> >> + * \var Accumulator::red
> > 
> > This was Accumulator::sum::red in v1, why has it changed ?
> 
> This is an anticipation on the Documentation series because Doxygen
> can't find Accumulator::sum::red because we use unamed structures to
> group items. I can keep the sum:: here and fix it in the next series if
> you prefer ?

If you look at the generated documentation without sum::, it's not good
either. Let's keep it and please doxygen later.

> >>   * \brief Sum of the average red values of each unsaturated cell in the zone
> >>   *
> >> - * \var Accumulator::gSum
> >> + * \var Accumulator::green
> >>   * \brief Sum of the average green values of each unsaturated cell in the zone
> >>   *
> >> - * \var Accumulator::bSum
> >> + * \var Accumulator::blue
> >>   * \brief Sum of the average blue values of each unsaturated cell in the zone
> >>   */
> >>  
> >> @@ -206,10 +206,10 @@ void Awb::generateZones(std::vector<RGB> &zones)
> >>  		RGB zone;
> >>  		double counted = awbStats_[i].counted;
> >>  		if (counted >= kMinZonesCounted) {
> >> -			zone.G = awbStats_[i].gSum / counted;
> >> +			zone.G = awbStats_[i].sum.green / counted;
> >>  			if (zone.G >= kMinGreenLevelInZone) {
> >> -				zone.R = awbStats_[i].rSum / counted;
> >> -				zone.B = awbStats_[i].bSum / counted;
> >> +				zone.R = awbStats_[i].sum.red / counted;
> >> +				zone.B = awbStats_[i].sum.blue / counted;
> >>  				zones.push_back(zone);
> >>  			}
> >>  		}
> >> @@ -242,9 +242,9 @@ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats,
> >>  				/* The cell is not saturated, use the current cell */
> >>  				awbStats_[awbRegionPosition].counted++;
> >>  				uint32_t greenValue = currentCell->greenRedAvg + currentCell->greenBlueAvg;
> >> -				awbStats_[awbRegionPosition].gSum += greenValue / 2;
> >> -				awbStats_[awbRegionPosition].rSum += currentCell->redAvg;
> >> -				awbStats_[awbRegionPosition].bSum += currentCell->blueAvg;
> >> +				awbStats_[awbRegionPosition].sum.green += greenValue / 2;
> >> +				awbStats_[awbRegionPosition].sum.red += currentCell->redAvg;
> >> +				awbStats_[awbRegionPosition].sum.blue += currentCell->blueAvg;
> >>  			}
> >>  		}
> >>  	}
> >> @@ -253,9 +253,9 @@ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats,
> >>  void Awb::clearAwbStats()
> >>  {
> >>  	for (unsigned int i = 0; i < kAwbStatsSizeX * kAwbStatsSizeY; i++) {
> >> -		awbStats_[i].bSum = 0;
> >> -		awbStats_[i].rSum = 0;
> >> -		awbStats_[i].gSum = 0;
> >> +		awbStats_[i].sum.blue = 0;
> >> +		awbStats_[i].sum.red = 0;
> >> +		awbStats_[i].sum.green = 0;
> >>  		awbStats_[i].counted = 0;
> >>  	}
> >>  }
> >> diff --git a/src/ipa/ipu3/algorithms/awb.h b/src/ipa/ipu3/algorithms/awb.h
> >> index ac8ccc84..3385ebe7 100644
> >> --- a/src/ipa/ipu3/algorithms/awb.h
> >> +++ b/src/ipa/ipu3/algorithms/awb.h
> >> @@ -35,9 +35,11 @@ struct Ipu3AwbCell {
> >>  
> >>  struct Accumulator {
> >>  	unsigned int counted;
> >> -	unsigned long long rSum;
> >> -	unsigned long long gSum;
> >> -	unsigned long long bSum;
> >> +	struct {
> >> +		uint64_t red;
> >> +		uint64_t green;
> >> +		uint64_t blue;
> >> +	} sum;
> >>  };
> >>  
> >>  class Awb : public Algorithm

-- 
Regards,

Laurent Pinchart