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

[Jean-Michel Hautbois]

Hi Laurent,

On 05/10/2021 03:01, Laurent Pinchart wrote:
> Hi Jean-Michel,
> 
> 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 ?

> 
>>   * \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
>