ipa: raspberrypi: Generalise statistics

At present, the controller algorithms access the bcm2835_isp_stats structure,
which is hardware specific. It would be desirable to abstract out the statistics
structure to remove hardware specific headers from the algorithms source files.

Define a new templated RegionStats class that encompasses region based
statistics generated by the ISP. For the VC4 ISP, this can be used to hold
RGB sums and focus FoM values.

Define a new Statistics structure that holds all the VC4 ISP statistics output.
This includes AGC histograms, AGC/AWB region sums and focus FoM regions.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/src/ipa/raspberrypi/statistics.h b/src/ipa/raspberrypi/statistics.h
new file mode 100644
index 00000000..ad486534
--- /dev/null
+++ b/src/ipa/raspberrypi/statistics.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2022, Raspberry Pi Ltd
+ *
+ * statistics.h - Raspberry Pi generic statistics structure
+ */
+#pragma once
+
+#include <memory>
+#include <stdint.h>
+#include <vector>
+
+#include "histogram.h"
+#include "region_stats.h"
+
+namespace RPiController {
+
+struct RgbySums {
+	RgbySums(uint64_t _rSum = 0, uint64_t _gSum = 0, uint64_t _bSum = 0, uint64_t _ySum = 0)
+		: rSum(_rSum), gSum(_gSum), bSum(_bSum), ySum(_ySum)
+	{
+	}
+	uint64_t rSum;
+	uint64_t gSum;
+	uint64_t bSum;
+	uint64_t ySum;
+};
+
+using RgbyRegions = RegionStats<RgbySums>;
+using FocusRegions = RegionStats<uint64_t>;
+
+struct Statistics {
+	/*
+	 * All region based statistics are normalised to 16-bits, giving a
+	 * maximum value of (1 << NormalisationFactorPow2) - 1.
+	 */
+	static constexpr unsigned int NormalisationFactorPow2 = 16;
+
+	/*
+	 * Positioning of the AGC statistics gathering in the pipeline:
+	 * Pre-WB correction or post-WB correction.
+	 * Assume this is post-LSC.
+	 */
+	enum class AgcStatsPos { PreWb, PostWb };
+	const AgcStatsPos agcStatsPos;
+
+	/*
+	 * Positioning of the AWB/ALSC statistics gathering in the pipeline:
+	 * Pre-LSC or post-LSC.
+	 */
+	enum class ColourStatsPos { PreLsc, PostLsc };
+	const ColourStatsPos colourStatsPos;
+
+	Statistics(AgcStatsPos a, ColourStatsPos c)
+		: agcStatsPos(a), colourStatsPos(c)
+	{
+	}
+
+	/* Histogram statistics. Not all histograms may be populated! */
+	Histogram rHist;
+	Histogram gHist;
+	Histogram bHist;
+	Histogram yHist;
+
+	/* Row sums for flicker avoidance. */
+	std::vector<RgbySums> rowSums;
+
+	/* Region based colour sums. */
+	RgbyRegions agcRegions;
+	RgbyRegions awbRegions;
+
+	/* Region based focus FoM. */
+	FocusRegions focusRegions;
+};
+
+} /* namespace RPiController */