ipa: rkisp1: Use frame counter for the request queued

Introduce a frameCount variable in the IPAFrameContext which increments
each time a request is queued. It is reset at configure call, when the
camera is started.

This will allow the frameCount to be used by other algorithms, without
having to keep multiple private frame counters.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/ipa/rkisp1/ipa_context.cpp

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 /*
- * Copyright (C) 2021, Ideas On Board
+ * Copyright (C) 2021-2022, Ideas On Board
  *
  * ipa_context.cpp - RkISP1 IPA Context
  */
@@ -113,4 +113,13 @@ namespace libcamera::ipa::rkisp1 {
  * \brief Analogue gain multiplier
  */
 
+/**
+ * \var IPAFrameContext::frameCount
+ * \brief Counter of requests queued to the IPA module
+ *
+ * The counter is reset to 0 when the IPA module is configured, and is
+ * incremented for each request being queued, after calling the
+ * Algorithm::prepare() function of all algorithms.
+ */
+
 } /* namespace libcamera::ipa::rkisp1 */