fmu-v2: add bootloader binary and SYS_BL_UPDATE param for BL updates

This allows a simple-to-use bootloader update mechanism to switch from
fmu-v2 to fmu-v3 target that has more flash.

ROMFS/CMakeLists.txt

@@ -103,6 +103,15 @@ if (config_io_board)
 		)
 endif()
 
+if (config_bl_file)
+	file(MAKE_DIRECTORY ${PX4_BINARY_DIR}/romfs_extras)
+	configure_file(${config_bl_file} ${PX4_BINARY_DIR}/romfs_extras COPYONLY)
+
+	list(APPEND extras_dependencies
+		${config_bl_file}
+		)
+endif()
+
 add_custom_command(OUTPUT romfs_extras.stamp
 	COMMAND ${CMAKE_COMMAND} -E make_directory ${romfs_gen_root_dir}/extras/
 	COMMAND ${CMAKE_COMMAND} -E make_directory ${PX4_BINARY_DIR}/romfs_extras/

ROMFS/px4fmu_common/extras/README.txt

@@ -0,0 +1,5 @@
+px4fmuv3_bl.bin: Bootloader binary of the PX4 Bootloader
+  (https://github.com/PX4/Bootloader)
+  based on commit 184b813699a9cfd6f43a5a21556a06b4372baf5f
+  for the target px4fmuv3_bl
+

ROMFS/px4fmu_common/init.d/rcS

@@ -211,6 +211,27 @@ else
 		param reset
 	fi
 
+	#
+	# Bootloader upgrade
+	#
+	if ver hwcmp PX4FMU_V2
+	then
+		set BL_FILE /etc/extras/px4fmuv3_bl.bin
+		if [ -f $BL_FILE ]
+		then
+			if param compare SYS_BL_UPDATE 1
+			then
+				param set SYS_BL_UPDATE 0
+				param save
+				echo "BL update..." >> $LOG_FILE
+				bl_update $BL_FILE
+				echo "BL update done" >> $LOG_FILE
+				reboot
+			fi
+		fi
+		unset BL_FILE
+	fi
+
 	#
 	# Start system state indicator.
 	#

cmake/configs/nuttx_px4fmu-v2_default.cmake

@@ -2,6 +2,8 @@ px4_nuttx_configure(HWCLASS m4 CONFIG nsh ROMFS y ROMFSROOT px4fmu_common IO px4
 
 #set(config_uavcan_num_ifaces 2)
 
+set(config_bl_file ${PX4_SOURCE_DIR}/ROMFS/px4fmu_common/extras/px4fmuv3_bl.bin)
+
 set(config_module_list
 	#
 	# Board support modules
@@ -62,7 +64,7 @@ set(config_module_list
 	#
 	# System commands
 	#
-	#systemcmds/bl_update
+	systemcmds/bl_update
 	#systemcmds/config
 	#systemcmds/dumpfile
 	#systemcmds/esc_calib

src/modules/systemlib/system_params.c

@@ -267,3 +267,25 @@ PARAM_DEFINE_INT32(SYS_HAS_MAG, 1);
  * @group System
  */
 PARAM_DEFINE_INT32(SYS_HAS_BARO, 1);
+
+/**
+ * Bootloader update
+ *
+ * If enabled, update the bootloader on the next boot.
+ *
+ * WARNING: do not cut the power during an update process, otherwise you will
+ * have to recover using some alternative method (e.g. JTAG).
+ *
+ * Instructions:
+ * - Insert an SD card
+ * - Enable this parameter
+ * - Reboot the board (plug the power or send a reboot command)
+ * - Wait until the board comes back up (or at least 2 minutes)
+ * - If it does not come back, check the file bootlog.txt on the SD card
+ *
+ * @boolean
+ * @reboot_required true
+ *
+ * @group System
+ */
+PARAM_DEFINE_INT32(SYS_BL_UPDATE, 0);