pipeline: raspberrypi: delayed_controls: Add user cookie to DelayedControls

Allow the caller to provide a cookie value to DelayedControls::reset and
DelayedControls::push. This cookie value is returned from DelayedControls::get
for the frame that has the control values applied to it.

The cookie value is useful in tracking when a set of controls has been applied
to a frame. In a subsequent commit, it will be used by the Raspberry Pi IPA to
track the IPA context used when setting the control values.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/pipeline/raspberrypi/delayed_controls.cpp

@@ -108,7 +108,7 @@ DelayedControls::DelayedControls(V4L2Device *device,
 		maxDelay_ = std::max(maxDelay_, controlParams_[id].delay);
 	}
 
-	reset();
+	reset(0);
 }
 
 /**
@@ -117,10 +117,11 @@ DelayedControls::DelayedControls(V4L2Device *device,
  * Resets the state machine to a starting position based on control values
  * retrieved from the device.
  */
-void DelayedControls::reset()
+void DelayedControls::reset(unsigned int cookie)
 {
 	queueCount_ = 1;
 	writeCount_ = 0;
+	cookies_[0] = cookie;
 
 	/* Retrieve control as reported by the device. */
 	std::vector<uint32_t> ids;
@@ -150,7 +151,7 @@ void DelayedControls::reset()
  *
  * \returns true if \a controls are accepted, or false otherwise
  */
-bool DelayedControls::push(const ControlList &controls)
+bool DelayedControls::push(const ControlList &controls, const unsigned int cookie)
 {
 	/* Copy state from previous frame. */
 	for (auto &ctrl : values_) {
@@ -184,6 +185,7 @@ bool DelayedControls::push(const ControlList &controls)
 			<< " at index " << queueCount_;
 	}
 
+	cookies_[queueCount_] = cookie;
 	queueCount_++;
 
 	return true;
@@ -204,7 +206,7 @@ bool DelayedControls::push(const ControlList &controls)
  *
  * \return The controls at \a sequence number
  */
-ControlList DelayedControls::get(uint32_t sequence)
+std::pair<ControlList, unsigned int> DelayedControls::get(uint32_t sequence)
 {
 	unsigned int index = std::max<int>(0, sequence - maxDelay_);
 
@@ -221,7 +223,7 @@ ControlList DelayedControls::get(uint32_t sequence)
 			<< " at index " << index;
 	}
 
-	return out;
+	return { out, cookies_[index] };
 }
 
 /**
@@ -280,7 +282,7 @@ void DelayedControls::applyControls(uint32_t sequence)
 	while (writeCount_ > queueCount_) {
 		LOG(RPiDelayedControls, Debug)
 			<< "Queue is empty, auto queue no-op.";
-		push({});
+		push({}, cookies_[queueCount_ - 1]);
 	}
 
 	device_->setControls(&out);

src/libcamera/pipeline/raspberrypi/delayed_controls.h

@@ -11,6 +11,7 @@
 
 #include <stdint.h>
 #include <unordered_map>
+#include <utility>
 
 #include <libcamera/controls.h>
 
@@ -31,10 +32,10 @@ public:
 	DelayedControls(V4L2Device *device,
 			const std::unordered_map<uint32_t, ControlParams> &controlParams);
 
-	void reset();
+	void reset(unsigned int cookie);
 
-	bool push(const ControlList &controls);
-	ControlList get(uint32_t sequence);
+	bool push(const ControlList &controls, unsigned int cookie);
+	std::pair<ControlList, unsigned int> get(uint32_t sequence);
 
 	void applyControls(uint32_t sequence);
 
@@ -78,6 +79,7 @@ private:
 	uint32_t queueCount_;
 	uint32_t writeCount_;
 	std::unordered_map<const ControlId *, RingBuffer<Info>> values_;
+	RingBuffer<unsigned int> cookies_;
 };
 
 } /* namespace RPi */

src/libcamera/pipeline/raspberrypi/raspberrypi.cpp

@@ -1066,7 +1066,7 @@ int PipelineHandlerRPi::start(Camera *camera, const ControlList *controls)
 	 * Reset the delayed controls with the gain and exposure values set by
 	 * the IPA.
 	 */
-	data->delayedCtrls_->reset();
+	data->delayedCtrls_->reset(0);
 
 	data->state_ = RPiCameraData::State::Idle;
 
@@ -1802,7 +1802,7 @@ void RPiCameraData::setIspControls(const ControlList &controls)
 
 void RPiCameraData::setDelayedControls(const ControlList &controls)
 {
-	if (!delayedCtrls_->push(controls))
+	if (!delayedCtrls_->push(controls, 0))
 		LOG(RPI, Error) << "V4L2 DelayedControl set failed";
 	handleState();
 }
@@ -1875,7 +1875,7 @@ void RPiCameraData::unicamBufferDequeue(FrameBuffer *buffer)
 		 * Lookup the sensor controls used for this frame sequence from
 		 * DelayedControl and queue them along with the frame buffer.
 		 */
-		ControlList ctrl = delayedCtrls_->get(buffer->metadata().sequence);
+		auto [ctrl, cookie] = delayedCtrls_->get(buffer->metadata().sequence);
 		/*
 		 * Add the frame timestamp to the ControlList for the IPA to use
 		 * as it does not receive the FrameBuffer object.