[libcamera-devel] [PATCH v4 3/4] ipa: ipu3: Change Accumulator structure layout

[Jean-Michel Hautbois]

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>
---
 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 97f5839f..bc0aa6fe 100644
--- a/src/ipa/ipu3/algorithms/awb.cpp
+++ b/src/ipa/ipu3/algorithms/awb.cpp
@@ -42,13 +42,13 @@ static constexpr uint32_t kMinGreenLevelInZone = 32;
  * \var Accumulator::counted
  * \brief Number of relevant regions used to calculate the sums
  *
- * \var Accumulator::rSum
+ * \var Accumulator::sum::red
  * \brief Sum of the red values in the zone
  *
- * \var Accumulator::gSum
+ * \var Accumulator::sum::green
  * \brief Sum of the green values in the zone
  *
- * \var Accumulator::bSum
+ * \var Accumulator::sum::blue
  * \brief Sum of the blue values in the zone
  */
 
@@ -173,10 +173,10 @@ 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);
 			}
 		}
@@ -209,9 +209,9 @@ 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;
 			}
 		}
 	}
@@ -220,9 +220,9 @@ 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
-- 
2.30.2