Embedding EPICS/RTEMS into Altera NIOS2 FPGA Softcore

1. Embedding EPICS/RTEMS into Altera NIOS2 FPGA Softcore Jeffrey O. Hill

2. Embedding EPICS/RTEMS into Altera NIOS2 FPGA Softcore • Overview • Requirements • Proof of Principal • Issues … • First Step – Wrap Altera NIOS2 GNU Tools • Next Step – Build RTEMS/NIOS GNU Tools • Future Plans

3. Requirements • Requirements for EPICS IOCs, LANSCE RF system upgrade • Must be deterministically synchronized with the timing system • Binding of captured waveforms with beam flavor attributes obtained from the timing system • Modal behavior changes of low level RF controls depending on the flavor of beam • Must move captured waveforms from FPGA, into the IOC, and out to Ethernet

4. Proof of Principal • Traditional VME/cPCI backplanes • Now they are becoming a bottleneck • There are Altera IP cores for • System processor • Ethernet interface • Can we distribute the solution? • One IOC on each cPCI RF board • Stream data directly, FPGA to Ethernet • A proof of principal is needed

5. Proof of Principal • Third party FPGA intellectual property libraries for ARM, MIPS, etc • Are well supported by the GNU tools • However, use of these IP modules involves licensing expense • Which our RF group prefers to avoid

6. Proof of Principal • Hardware • Altera NIOS Embedded Evaluation Kit • NIOS II Reference Platform on FPGA • Software • GNU Cross Development Tools • RTEMS OS • EPICS IOC

7. Issues… • Alteradoes • Provide source code for their nios2 enhancements to binutils/gcc/newlib • Modern version now available • FSF binutils 2.20 for nios2 • FSF gcc 4.1 for nios2 • FSF newlib 1.16 for nios2 • Alteradoesn'tfeed back their nios2 enhancements into the asynchronous FSF releases of binutils/gcc/newlib

8. Issues… • RTEMS doesfeed their enhancements back into the asynchronous FSF releases of binutils/gcc/newlib • RTEMS does depend on these enhancements • RTEMS 4.10 appears to require a recent release of gnu gcc and newlib

9. Issues… • RTEMS doesn’t supply it’s nios2 support files in any production release, but • These files can be obtained by fetching the main development trunk out of CVS • In summary, bringing all of the players together can be somewhat complicated …

10. The GNU Tool Chain • Various components independently maintained but working closely together • Binutils • Loader, assembler, and others … • Newlib • C runtime library for embedded systems • GCC • We use … • C and C++ compilers • Proper runtime support for C++ is essential • Various support libraries

11. First Step – Wrap Altera NIOS2 GNU Tools • I tried the instructions available at http://www.nios2rtems.com/ • Create wrapper script for altera-built gnu cross compiler binaries • Build newlib, and then rtems • Very helpful tutorials at this site • See details about creating rtemsbsp using output from Altera’snios2-bsp tool • Unfortunately, some insurmountable issues with this specific approach • The Altera built gnu cross compiler… • Configured with –disable-threads • Compiler’s c++ runtime isn't using rtems primitives for synchronization

12. Next Step – Build RTEMS/NIOS GNU Tools • Altera enhanced sources for binutils/gcc/newlib are available • Perhaps we can configure and build them specifically for RTEMS • Configuring RTEMS thread model • Configuring RTEMS BSP startup libraries to be implicitly linked in

13. Next Step – Build RTEMS/NIOS GNU Tools • RTEMS main trunk is currently incompatible with newlib 1.16 • Two options • Back annotate rtems nios2 support files from main trunk into earlier RTEMS release compatible with Altera’snewlib 1.16 • Forward annotate newlib nios2 support files from Altera modified FSF newlib 1.16 to FSF newlib 1.18 • Currently I am concentrating on 2, but expect to eventually use a combination of 1 and 2 in production systems

14. Next Step – Build RTEMS/NIOS GNU Tools • Typical steps when installing a GNU package from source • Obtain source • Patch source • Run autoconf in the source • Configure the source • Build the package • Install the package

15. Applying Patches • “cat ../gcc-4.3.2-rtems4.10-20080917.diff | patch -p1” • “find . -name "*.rej" –print” • Sometimes we have to fix by hand what is found in *.rej

16. Installing Prerequisite Tools • Need autoconf and automake • Always run first autoreconf in source tree if patches apply to *.am, *.ac, *.in, … • Maybe running autoconf isn't enough • Different packages need different versions of these tools • Sometimes the exact same version is needed • Sometimes the same or newer version is needed? • Different components have different requirements

17. Installing Prerequisite Tools • Need gnu libgmp, libppl, libelf… • http://gcc.gnu.org/install/prerequisites.html • But in practice, the uninitiated may iterate a few times as follows… • Run gnu “configure” • Look in config.log for “error” • If there are errors install missing packages • Run configure again …

18. From Altera, NIOS Enhanced binutils 2.20 and GCC 4.1 • Altera Nios enhanced FSF source code • ftp://ftp.altera.com/outgoing/download/support/ip/processors/nios2/gnu/ • I used nios2_gnu_gcc4_11.0.tgz • Apply RTEMS patches • ftp://ftp.rtems.com/pub/rtems/SOURCES/4.10/ • ftp://ftp.rtems.com/pub/rtems/SOURCES/4.7

19. Modify gcc Sources for NIOS2/RTEMS • Added gcc/config/nios2/rtems.h • Added gcc/config/nios2/t-rtems • Added new case in gcc/config.gcc • Added symbolic link to gcc/newlib

20. From FSF, newlib 1.18 • http://sourceware.org/newlib/ • Altera’s newlib 1.16 • Incompatible with RTEMS 4.11- • Transplanting NIOS2 specific code from Altera’s Newlib 1.16 wasn't too daunting • Applied RTEMS 4.10 patches • Patch file “newlib-1.18.0-rtems4.10-20110518” • Some RTEMS modifications for nios2

21. Modify newlib 1.18 Sources for NIOS2/RTEMS • Modified • newlib/include/machine/setjmp.h • newlib/libc/sys/rtems/machine/_types.h • newlib/libc/sys/rtems/crt0.c

22. Build gcc, for nios2/rtems • Run autoconf in gcc source tree • “mkdir b-gcc” • “cd b-gcc” • Run configure ../gcc/altera-gcc-4.1-patched/configure --target=nios2-rtems --enable-threads --with-gnu-as --with-gnu-ld --with-newlib --verbose --disable-libstdcxx-pch --enable-multilib --enable-languages="c,c++" --prefix=$(INSTALL_RTEMS) • “make all” followed by “make install”

23. Get rtems Source Code • I used RTEMS 4.11- • But, nios2 support isn't included in any public rtems release • I obtained 4.11- from anonymous CVS • In the cvs trunk, nios2 support is bundled

24. Build rtemsfor nios2 • “mkdir b-rtems” • “cd b-rtems” • ../rtems-4.11-/rtems/configure --target=nios2-rtems --enable-posix --enable-networking --enable-rtbg --enable-cxx --disable-tests --enable-rtemsbsp=neek --prefix=$(INSTALL_RTEMS)

25. But some problems… • The g++ appears to expect c++ header are in a different location than where they are actually installed. • Still working in this issue • Have booted RTEMS on NIOS, but not with C++ code.

26. Future Plans • Altera Triple-Speed-Ethernet driver • Port Linux Ethernet driver to RTEMS • Regression Tests • Performance tests

27. References • http://www.nios2rtems.com • http://www.alterawiki.com/wiki/CrossGcc • http://www.ifp.illinois.edu/~nakazato/tips/xgcc.html