PreFlightCheck: add checks for CPU load

ROMFS/px4fmu_common/init.d-posix/rcS

@@ -186,6 +186,7 @@ then
 
 	param set TRIG_INTERFACE 3
 
+	param set COM_CPU_MAX -1
 fi
 
 # Adapt timeout parameters if simulation runs faster or slower than realtime.

src/modules/commander/Arming/PreFlightCheck/CMakeLists.txt

@@ -47,6 +47,7 @@ px4_add_library(PreFlightCheck
 	checks/ekf2Check.cpp
 	checks/failureDetectorCheck.cpp
 	checks/manualControlCheck.cpp
+	checks/cpuResourceCheck.cpp
 )
 target_include_directories(PreFlightCheck PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(PreFlightCheck PUBLIC ArmAuthorization HealthFlags)

src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.cpp

@@ -298,6 +298,7 @@ bool PreFlightCheck::preflightCheck(orb_advert_t *mavlink_log_pub, vehicle_statu
 	}
 
 	failed = failed || !manualControlCheck(mavlink_log_pub, reportFailures);
+	failed = failed || !cpuResourceCheck(mavlink_log_pub, reportFailures);
 
 	/* Report status */
 	return !failed;

src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.hpp

@@ -115,4 +115,5 @@ class PreFlightCheck
 	static bool check_calibration(const char *param_template, const int32_t device_id);
 	static bool manualControlCheck(orb_advert_t *mavlink_log_pub, const bool report_fail);
 	static bool airframeCheck(orb_advert_t *mavlink_log_pub, const vehicle_status_s &status);
+	static bool cpuResourceCheck(orb_advert_t *mavlink_log_pub, const bool report_fail);
 };

src/modules/commander/Arming/PreFlightCheck/checks/cpuResourceCheck.cpp

@@ -0,0 +1,76 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2020 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include "../PreFlightCheck.hpp"
+
+#include <drivers/drv_hrt.h>
+#include <systemlib/mavlink_log.h>
+#include <lib/parameters/param.h>
+#include <uORB/Subscription.hpp>
+#include <uORB/topics/cpuload.h>
+
+using namespace time_literals;
+
+bool PreFlightCheck::cpuResourceCheck(orb_advert_t *mavlink_log_pub, const bool report_fail)
+{
+	bool success = true;
+
+	uORB::SubscriptionData<cpuload_s> cpuload_sub{ORB_ID(cpuload)};
+	cpuload_sub.update();
+
+	float cpuload_percent_max;
+	param_get(param_find("COM_CPU_MAX"), &cpuload_percent_max);
+
+	if (cpuload_percent_max > 0.f) {
+
+		if (hrt_elapsed_time(&cpuload_sub.get().timestamp) > 2_s) {
+			success = false;
+
+			if (report_fail) {
+				mavlink_log_critical(mavlink_log_pub, "Fail: No CPU load information");
+			}
+		}
+
+		const float cpuload_percent = cpuload_sub.get().load * 100.f;
+
+		if (cpuload_percent > cpuload_percent_max) {
+			success = false;
+
+			if (report_fail) {
+				mavlink_log_critical(mavlink_log_pub, "Fail: CPU load too high: %3.1f%%", (double)cpuload_percent);
+			}
+		}
+	}
+
+	return success;
+}

src/modules/commander/commander_params.c

@@ -899,3 +899,16 @@ PARAM_DEFINE_INT32(COM_MOT_TEST_EN, 1);
  * @increment 0.1
  */
 PARAM_DEFINE_FLOAT(COM_KILL_DISARM, 5.0f);
+
+/**
+ * Maximum allowed CPU load to still allow arming
+ *
+ * A negative value disables the check.
+ *
+ * @group Commander
+ * @unit %
+ * @min -1
+ * @max 100
+ * @increment 1
+ */
+PARAM_DEFINE_FLOAT(COM_CPU_MAX, 90.0f);