ipa: raspberrypi: Generalise the autofocus algorithm

Remove any hard-coded assumptions about the target hardware platform
from the autofocus algorithm. Instead, use the "target" string provided
by the camera tuning config and generalised statistics structures to
determing parameters such as grid and region sizes.

Additionally, PDAF statistics are represented by a generalised region
statistics structure to be device agnostic.

These changes also require the autofocus algorithm to initialise
region weights on the first frame's prepare()/process() call rather
than during initialisation.

Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Tested-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/src/ipa/raspberrypi/cam_helper_imx708.cpp b/src/ipa/raspberrypi/cam_helper_imx708.cpp
index 1f213d3c..641ba18f 100644
--- a/src/ipa/raspberrypi/cam_helper_imx708.cpp
+++ b/src/ipa/raspberrypi/cam_helper_imx708.cpp
@@ -69,11 +69,14 @@ private:
 	/* Largest long exposure scale factor given as a left shift on the frame length. */
 	static constexpr int longExposureShiftMax = 7;
 
+	static constexpr int pdafStatsRows = 12;
+	static constexpr int pdafStatsCols = 16;
+
 	void populateMetadata(const MdParser::RegisterMap &registers,
 			      Metadata &metadata) const override;
 
 	static bool parsePdafData(const uint8_t *ptr, size_t len, unsigned bpp,
-				  PdafData &pdaf);
+				  PdafRegions &pdaf);
 
 	bool parseAEHist(const uint8_t *ptr, size_t len, unsigned bpp);
 	void putAGCStatistics(StatisticsPtr stats);
@@ -120,11 +123,11 @@ void CamHelperImx708::prepare(libcamera::Span<const uint8_t> buffer, Metadata &m
 	size_t bytesPerLine = (mode_.width * mode_.bitdepth) >> 3;
 
 	if (buffer.size() > 2 * bytesPerLine) {
-		PdafData pdaf;
+		PdafRegions pdaf;
 		if (parsePdafData(&buffer[2 * bytesPerLine],
 				  buffer.size() - 2 * bytesPerLine,
 				  mode_.bitdepth, pdaf))
-			metadata.set("pdaf.data", pdaf);
+			metadata.set("pdaf.regions", pdaf);
 	}
 
 	/* Parse AE-HIST data where present */
@@ -239,7 +242,7 @@ void CamHelperImx708::populateMetadata(const MdParser::RegisterMap &registers,
 }
 
 bool CamHelperImx708::parsePdafData(const uint8_t *ptr, size_t len,
-				    unsigned bpp, PdafData &pdaf)
+				    unsigned bpp, PdafRegions &pdaf)
 {
 	size_t step = bpp >> 1; /* bytes per PDAF grid entry */
 
@@ -248,13 +251,17 @@ bool CamHelperImx708::parsePdafData(const uint8_t *ptr, size_t len,
 		return false;
 	}
 
+	pdaf.init({ pdafStatsCols, pdafStatsRows });
+
 	ptr += 2 * step;
-	for (unsigned i = 0; i < PDAF_DATA_ROWS; ++i) {
-		for (unsigned j = 0; j < PDAF_DATA_COLS; ++j) {
+	for (unsigned i = 0; i < pdafStatsRows; ++i) {
+		for (unsigned j = 0; j < pdafStatsCols; ++j) {
 			unsigned c = (ptr[0] << 3) | (ptr[1] >> 5);
 			int p = (((ptr[1] & 0x0F) - (ptr[1] & 0x10)) << 6) | (ptr[2] >> 2);
-			pdaf.conf[i][j] = c;
-			pdaf.phase[i][j] = c ? p : 0;
+			PdafData pdafData;
+			pdafData.conf = c;
+			pdafData.phase = c ? p : 0;
+			pdaf.set(libcamera::Point(j, i), { pdafData, 1, 0 });
 			ptr += step;
 		}
 	}