PreFlightCheck: Detect missing FMU SD card

Signed-off-by: Claudio Micheli <claudio@auterion.com>

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

@@ -48,6 +48,7 @@ px4_add_library(PreFlightCheck
 	checks/failureDetectorCheck.cpp
 	checks/manualControlCheck.cpp
 	checks/cpuResourceCheck.cpp
+	checks/sdcardCheck.cpp
 )
 target_include_directories(PreFlightCheck PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(PreFlightCheck PUBLIC ArmAuthorization HealthFlags sensor_calibration)

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

@@ -64,6 +64,7 @@ bool PreFlightCheck::preflightCheck(orb_advert_t *mavlink_log_pub, vehicle_statu
 	bool failed = false;
 
 	failed = failed || !airframeCheck(mavlink_log_pub, status);
+	failed = failed || !sdcardCheck(mavlink_log_pub, report_failures);
 
 	/* ---- MAG ---- */
 	{

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

@@ -119,4 +119,5 @@ private:
 	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);
+	static bool sdcardCheck(orb_advert_t *mavlink_log_pub, const bool report_fail);
 };

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

@@ -0,0 +1,74 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 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 <lib/parameters/param.h>
+#include <systemlib/mavlink_log.h>
+#ifdef __PX4_DARWIN
+#include <sys/param.h>
+#include <sys/mount.h>
+#else
+#include <sys/statfs.h>
+#endif
+
+bool PreFlightCheck::sdcardCheck(orb_advert_t *mavlink_log_pub, const bool report_fail)
+{
+	const char *microsd_dir = PX4_STORAGEDIR;
+	bool success = true;
+	struct statfs statfs_buf;
+	uint64_t total_bytes = 0;
+
+	int32_t reporting_enabled = 0;
+	param_get(param_find("COM_ARM_SDCARD"), &reporting_enabled);
+
+	if (reporting_enabled == 0) {
+		return success;
+	}
+
+	if (statfs(microsd_dir, &statfs_buf) == 0) {
+		total_bytes = (uint64_t)statfs_buf.f_blocks * statfs_buf.f_bsize;
+	}
+
+	if (total_bytes == 0) { // on NuttX we get 0 total bytes if no SD card is inserted
+
+		if (reporting_enabled == 2) {
+			success = false;
+		}
+
+		if (report_fail && reporting_enabled > 0) {
+			mavlink_log_critical(mavlink_log_pub, "Warning! Missing FMU SD Card.");
+		}
+	}
+
+	return success;
+}

src/modules/commander/commander_params.c

@@ -985,3 +985,17 @@ PARAM_DEFINE_FLOAT(COM_LKDOWN_TKO, 3.0f);
 * @value 1 Enabled
 */
 PARAM_DEFINE_INT32(COM_ARM_ARSP_EN, 1);
+
+/**
+ * Enable FMU SD card detection check
+ *
+ * This check detects if the FMU SD card is missing.
+ * Depending on the value of the parameter, the check can be
+ * disabled, warn only or deny arming.
+ *
+ * @group Commander
+ * @value 0 Disabled
+ * @value 1 Warning only
+ * @value 2 Enforce SD card presence
+ */
+PARAM_DEFINE_INT32(COM_ARM_SDCARD, 1);