AirborneCodeReorg

Problem statement

Current airborne code has gone a little bit out of control and is in deep need of a reorganization.

Fixed wing airframes have makefile directly in them - we can't change anything in the airborne code without breaking everybody's airframe

 ap.srcs += commands.c
 ap.CFLAGS += -DACTUATORS=\"servos_4015_MAT_hw.h\" -DSERVOS_4015_MAT
 ap.srcs += $(SRC_ARCH)/servos_4015_MAT_hw.c actuators.c
 ap.CFLAGS += -DRADIO_CONTROL
 ap.srcs += radio_control.c $(SRC_ARCH)/ppm_hw.c
 [...] 
 ap.CFLAGS += -DNAV -DAGR_CLIMB -DLOITER_TRIM -DALT_KALMAN -DWIND_INFO
 ap.srcs += nav.c fw_h_ctl.c fw_v_ctl.c

Booz uses "susbsystem" Makefiles

 include $(PAPARAZZI_SRC)/conf/autopilot/booz2_common.makefile
 include $(CFG_BOOZ)/booz2_autopilot.makefile
 include $(CFG_BOOZ)/subsystems/booz2_radio_control_ppm.makefile
 include $(CFG_BOOZ)/subsystems/booz2_actuators_mkk.makefile
 include $(CFG_BOOZ)/subsystems/booz2_imu_b2v1.makefile

This is the Makefile part of a booz vehicle using a booz2 IMU, mikrokopter actuators and ppm radio control

There is also the "module" facility which is very good for optional features.

There are 3 kinds of code in the airborne directory

• generic code (that doesn't depend on any architecture or plateforme) - there's a lot of it and it should probably be sorted by type of functionalities
  • fixed_wings
  • thrust_vectoring
• processor specific code (stm32, lpc21, avr, etc...)
• plateforme specific code (tiny, booz, lisa, etc...)

Names

Booz both stands for the LPC2148 quad board and the quadrotor autopilot code - Let's call the quadrotor autopilot "Baloo" ( if you got a better name, don't hesitate, but be quick). What about a name for the fixedwing code ? (which has been called Paparazzi until now and collides with the name of the project itself )

Proposed reorganization

1. Move more code to modules
2. Move Makefile out of the airframe file as much as possible (modules have there own makefile / booz include makefile approach: "conf/autopilot/fixedwing_common.makefile")
3. Send mailing list message requesting to change the makefile section of airframes into new include structure
4. Once many users have this in place and the wiki page is good, we can start to move code

cdewagter

Proposed Directory structure

relative to sw/airborne

 baloo/ (a target)
 fixedwing/(or a new name, another target)
 radio_control/ (a subsystem)
 gps/ (another subsystem)
 ...(more subsystems)
 imu.[ch]
 imu/
 modules/
 arch/
   avr/
   lpc21/
   stm32/
   omap/

each susbsystem having several implementations gets a subdirectory

 imu.[ch]
 imu/
   imu_xsense.[ch]
   imu_b2.[ch]

in each of the directory under arch, a replication of the toplevel directory containing architecture specific implementations

 imu.h
 imu/
   imu_xsense.[ch]
   imu_b2.[ch]
 arch/
   lpc21/
     imu/
       imu_xsense_arch.[ch]
       imu_b2_arch.[ch]
   stm32/
     imu/
       imu_xsense_arch.[ch]
       imu_b2_arch.[ch]
 

Replace makefile section with xml

of course leave the possibility to have a makefile section, but the normal user would have something like

airframe.xml	=>	Makefile.ac
<target name="booz2_autopilot"> <subsystem name="radio_control" type="ppm"/> <subsystem name="actuators" type="mkk"/> <subsystem name="imu" type="b2v1"/> </target>		include $(PAPARAZZI_SRC)/conf/autopilot/booz2_common.makefile include $(CFG_BOOZ)/booz2_autopilot.makefile include $(CFG_BOOZ)/subsystems/booz2_radio_control_ppm.makefile include $(CFG_BOOZ)/subsystems/booz2_actuators_mkk.makefile include $(CFG_BOOZ)/subsystems/booz2_imu_b2v1.makefile

put defines in here that get written in airframe.h

airframe.xml	=>	Makefile.ac
<target name="booz2_autopilot"> <subsystem name="actuators" type="mkk"> <define name="NB" value="4"/> <define name="ADDR" value="{ 0x52, 0x54, 0x56, 0x58 }"/> </subsystem> <subsystem name="imu" type="b2v1"/> </target>
		include $(PAPARAZZI_SRC)/conf/autopilot/booz2_common.makefile include $(CFG_BOOZ)/subsystems/booz2_radio_control_ppm.makefile include $(CFG_BOOZ)/subsystems/booz2_imu_b2v1.makefile
		airframe.h
		#define ACTUATORS_MKK_NB 4 #define ACTUATORS_MKK_ADDR {0x52,0x54,0x56,0x58}

set makefile variables

airframe.xml	=>	Makefile.ac
<target name="booz2_autopilot"> <subsystem name="gps" type="ubx"> <param name="GPS_UART_NR" value="1"/> <param name="GPS_BAUD" value="38400"/> </subsystem> </target>		GPS_UART_NR=1 GPS_BAUD=38400 include $(CFG_BOOZ)/subsystems/booz2_gps_ubx.makefile

Include guards

All headers have to be checked for missing include guards, style template:

#ifndef <MODULE>_<TARGET>_<FILENAME>_H
#define <MODULE>_<TARGET>_<FILENAME>_H
[code]
#endif /* <MODULE>_<TARGET>_<FILENAME>_H */

Example for sw/airborne/csc/airspeed.h:

#ifndef CSC_AP_AIRSPEED_H
#define CSC_AP_AIRSPEED_H
[code]
#endif /* CSC_AP_AIRSPEED_H */

Misc

• All headers are defined relative to sw/airborne (limit the -I to -Isw/airborne and the generated code)

 #include "baloo/whatever.h"

• Generated headers are indicated by their directory

 #include "generated/airframe.h"

Proposed methodology

[6:50:19 PM] Christophe De Wagter: "builing a new road is easy: nobody can ride until it is finished." ... "for road-works on an existing road there are 2 options: a) a non-important road can be closed for a while during roadworks b) but for roads that are too important: you need to keep a lane open: that is more work than closing it down but in the end keeps the total traffic problem minimal" [6:51:05 PM] Christophe De Wagter: I think that a gradual approach might be slightly more work, but keeps the road open and developments running.

I could not agree more!

Let's start with a subsystem that is both simple enough yet representative, I suggest radio control For now people using fixed wing have

 ap.CFLAGS += -DRADIO_CONTROL
 ap.srcs += radio_control.c $(SRC_ARCH)/ppm_hw.c

Let's ask people to remove those lines from their makefile and replace with

 <target name="fixed_wings" board="tiny_2.11">
   <subsystem name="radio_control" type="ppm"/>
 </target>

which will generate the following in Makefile.ac

 include $(PAPARAZZI_SRC)/conf/autopilot/fixed_wing_common.makefile
 include $(PAPARAZZI_SRC)/conf/boards/tiny_2.11.makefile
 include $(CFG_FIXED_WINGS)/radio_control_ppm.makefile

and the following in airframe.f

#define USE_RADIO_CONTROL 1

Outcomes (Currently in no particular order)

Replacing the makefile section of the airframe file with xml should:-

1. Provide a simpler to understand and consistent syntax for end users.
2. Enable Paparazzi centre to provide a list of all targets for an airframe.
3. Simplify the design of tools that automatically generate airframe files.
4. Simplify the process of documenting the airframe file and any future additions to it.

The reorganisation of directory structures is aimed at simplifying development and maintainance. The aim here is to provide :

1. A consistent structure for all targets, all architectures and all subsystems.
2. A structure that informs the naming of files.
3. A route to eventually enable the merging of fixed wing and rotor craft code bases.