Thanks to MAPGPS from http://www.ardrone-flyers.com for testing my tools.
You need:
- Linux! I used Ubuntu 10.10
- ARDrone linux kernel source (get it from [1])
- ARDrone linux kernel config (get it from [2])
- The Sourcery G++ toolchain (get it from [3] or [4] )
- My plftool, usb_flash tool (see below)
- The old parrot flash tool (for ardrone_usb_bootloader.bin)
- libusb-0.1 (linux) or libusb-win32 (windows)
- zlib
Getting & Compiling plftool + usb_flash tool
These tools are not yet released. Thus I will not provide binaries for windows, instead you have to compile them by yourself. For windows, you need to use mingw32.
Getting the sources
The sources are stored at my google code project. In order to get them, you need to install a svn client. For linux you then call something like this:
svn checkout http://ardrone-tool.googlecode.com/svn/projects/libplf/trunk libplf svn checkout http://ardrone-tool.googlecode.com/svn/projects/usb_flash/trunk usb_flash svn checkout http://ardrone-tool.googlecode.com/svn/projects/plftool/trunk plftool
Compiling
Now that you got the sources, you need to compile them. First start with libplf as this is needed by all projects. The library contains the code to read and write .plf files.
cd libplf make cd ..
When compiling with mingw32 call "make -f Makefile.w32" instead.
If libplf was compiled succesfully you should get either a libplf.so or libplf.dll file.
Next compile plftool and usb_flash:
cd plftool make cd .. cd usb_flash make cd ..
When compiling with mingw32, call "make -f Makefile.w32" instead.
This should create plftool(.exe) and usb_flash(.exe).
For Linux, if you do not want to install the libplf.so file, you need to call plftool and usb_flash with LD_LIBRARY_PATH=<path_to_the_folder_where_libplf.so_is_located> prefix.
E.g.
LD_LIBRARY_PATH=/home/scorp2kk/projects/ardrone/tools/libplf plftool
For Windows, you need to add the folder where libplf.dll is located to your PATH variable before calling usb_flash or plftool.
Patching the kernel
As Parrot's published source code does not match the kernel delivered with firmware > 1.3.3, a patch is required to ensure correct behaviour. This patch mainly affects p6_sdhci.c.
You can get the patch from here. To apply it, just call:
cd linux-2.6.27 patch -p1 < p6_sdhci-patch1.patch
Compiling the kernel
Now as the kernel is patched, you should use Parrot's original config [2] and cross-compile the sources with Sourcery G++. Basically you need to do something like this (don't forget to add the Sourcery' bin directory to your PATH):cp ARDrone_Version_20100809_1_2-busybox.config .config make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- zImage
After a few minutes (or hours) make informs you that the zImage file is available:
Kernel: arch/arm/boot/Image is ready Kernel: arch/arm/boot/zImage is ready
Creating a kernel.plf file
If you got your zImage, it is time to build a kernel.plf file from it. This is done by plftool. plftool expects a build-ini file that describes the plf file. A sample ini file can be found at plftool/samples/kernel. Using the sample kernel.ini, you only have to modify the "File=" parameters in section "[zImage]" and "[BootParams]" so they point to the zImage file and to a text file, the boot parameters are located in (e.g. called bootparams.txt).To create the kernel.plf from the kernel.ini, just call:
plftool -b kernel.ini -o kernel.plf
The tool should output something similar to this and create the kernel.plf file.
Creating kernel.plf based on this config: File [HdrVersion: 11 EntryPoint: 0x40800000; Version: 0.0.0 TargetPlat=4, TargetAppl=78, HwCompat=0, LangZone=0] zImage @ 0x40800000 (zImage) initrd @ ---------- (no initrd) bootparams @ 0x40700000 (bootparams.txt) *** kernel.plf created ***
Testing the kernel.plf file
If kernel.plf file was created, it is time to test this file. First inspect it with plftool:plftool -d -i kernel.plfHave a look at dwFileType, dwEntryPoint and Section->LoadAddr.
If it looks okay, it is time to start (not flash!) the kernel:
- Copy ardrone_usb_bootloader.bin to the folder of usb_flash
- Connect the drone to your PC via USB (the LED should be RED)
- Connect the BATTERY to your drone (the LED becomes GREEN)
- Check if the device was found (with lsusb)
- Start usb_flash in TEST mode:
usb_flash -t kernel.plf
This will load (NOT flash) the kernel over USB. In general, it is helpful to observe A.R. Drone's serial port, as the whole boot sequence is shown there. usb_flash outputs on success:
... Mode: kernel test *** VERIFICATION *** Verifying ardrone_usb_bootloader.bin Verifying test_kernel.plf *** DOWNLOADING USB BOOTLOADER *** Try [00/10] to connect to VID: 0x19cf PID: 0x1000 Found a possible device: - Manufacturer: Parrot SA - Product: P6 USB Stage1 - Serialnumber: ? - Number of configurations: 1 Sending bootloader (0x5b20 bytes) - Send Hello P6 (0xA3) Success!!! Checksum returned: 0x5256 Expected: 0x5256 => OK Starting the bootloader... *** INSTALLER DOWNLOAD *** Closing usb connection... Try [00/10] to connect to VID: 0x19cf PID: 0x1000 Found a possible device: - Manufacturer: Parrot SA - Product: P6 USB Stage1 - Serialnumber: ? - Number of configurations: 1 loading installer Uploading file: test_kernel.plf Error Code returned: 0x00000000 ==> OK *** INSTALLATION DONE ***
If everything works, the kernel boots up, WiFi ist started and you should be able to connect to the drone with telnet.
Check the kernel version with
uname -a
If the default kernel starts without problems, you can now begin to modify the kernel config.
Flashing the kernel to NAND works but I still need to modify the plftool.. so stay tuned.
Happy hacking :-)
[1] https://projects.ardrone.org/documents/show/19
[2] https://projects.ardrone.org/documents/show/18
[3] https://projects.ardrone.org/documents/show/20
[4] http://www.codesourcery.com/sgpp/lite/arm/portal/release858
