May 052018

So, at long last, I finally saw this in my chroot‘s /var/log/emerge.log:

1524887925: Started emerge on: Apr 28, 2018 03:58:45
1524887926:  *** emerge --oneshot sys-devel/gcc::musl
1524888211:  >>> emerge (1 of 1) sys-devel/gcc-7.3.0 to /
1524888212:  === (1 of 1) Cleaning (sys-devel/gcc-7.3.0::/root/musl/sys-devel/gcc/gcc-7.3.0.ebuild)
1524888307:  === (1 of 1) Compiling/Packaging (sys-devel/gcc-7.3.0::/root/musl/sys-devel/gcc/gcc-7.3.0.ebuild)
1525472690:  === (1 of 1) Merging (sys-devel/gcc-7.3.0::/root/musl/sys-devel/gcc/gcc-7.3.0.ebuild)
1525472838:  >>> AUTOCLEAN: sys-devel/gcc:7.3.0
1525473358:  === (1 of 1) Post-Build Cleaning (sys-devel/gcc-7.3.0::/root/musl/sys-devel/gcc/gcc-7.3.0.ebuild)
1525473358:  ::: completed emerge (1 of 1) sys-devel/gcc-7.3.0 to /
1525473360:  *** Finished. Cleaning up...
1525473373:  *** exiting successfully.

That’s 6 days, 18 hours and 32 minutes, of solid compiling. BUT WE GOT THERE!

What’s left? This:

Calculating dependencies... done!
[ebuild     U  ] sys-libs/musl-1.1.19 [1.1.18]
[binary   R    ] sys-libs/zlib-1.2.11-r1
[binary   R    ] app-arch/xz-utils-5.2.3
[ebuild     U  ] sys-libs/ncurses-6.1-r2 [6.0-r1]
[binary   R    ] sys-libs/readline-7.0_p3
[binary   R    ] virtual/libintl-0-r2
[binary   R    ] dev-lang/python-exec-2.4.5
[binary   R    ] virtual/libiconv-0-r2
[binary   R    ] sys-apps/gentoo-functions-0.12
[binary   R    ] dev-libs/libpcre-8.41-r1
[binary   R    ] sys-apps/sed-4.2.2
[binary   R    ] app-arch/bzip2-1.0.6-r8
[binary   R    ] dev-libs/gmp-6.1.2
[binary   R    ] app-shells/bash-4.4_p12
[binary   R    ] sys-apps/file-5.32
[binary   R    ] sys-devel/gnuconfig-20170101
[binary   R    ] dev-libs/mpfr-3.1.6
[binary   R    ] app-misc/c_rehash-1.7-r1
[binary   R    ] app-misc/mime-types-9
[binary   R    ] app-arch/tar-1.29-r3
[binary   R    ] app-arch/gzip-1.8
[binary   R    ] dev-libs/mpc-1.0.3
[binary   R    ] sys-devel/gcc-config-1.8-r1
[binary   R    ] app-misc/editor-wrapper-4
[binary   R    ] sys-apps/less-529
[binary   R    ] sys-apps/debianutils-4.8.3
[binary   R    ] net-libs/libmnl-1.0.4
[binary   R    ] sys-libs/libseccomp-2.3.2
[binary   R    ] dev-libs/popt-1.16-r2
[binary   R    ] sys-libs/e2fsprogs-libs-1.43.6
[binary   R    ] sys-devel/binutils-config-5-r4
[binary   R    ] dev-libs/libffi-3.2.1
[binary   R    ] virtual/libffi-3.0.13-r1
[binary   R    ] sys-apps/sysvinit-2.88-r9
[binary   R    ] sys-apps/opentmpfiles-0.1.3
[binary   R    ] virtual/tmpfiles-0
[binary   R    ] app-text/manpager-1
[binary   R    ] sys-libs/cracklib-2.9.6-r1
[binary   R    ] sys-apps/install-xattr-0.5
[binary   R    ] app-editors/nano-2.8.7
[binary   R    ] app-portage/elt-patches-20170815
[binary   R    ] sys-devel/m4-1.4.17
[binary   R    ] app-arch/unzip-6.0_p21-r2
[binary   R    ] sys-devel/autoconf-wrapper-13
[binary   R    ] sys-devel/bison-3.0.4-r1
[binary   R    ] sys-devel/flex-2.6.4-r1
[binary   R    ] dev-libs/libltdl-2.4.6
[binary   R    ] sys-devel/automake-wrapper-10
[binary   R    ] app-text/sgml-common-0.6.3-r6
[binary   R    ] dev-libs/libgpg-error-1.27-r1
[ebuild  N     ] dev-lang/perl-5.24.3-r1  USE="-berkdb -debug -doc -gdbm -ithreads"
[ebuild  N     ] sys-kernel/linux-headers-4.13  USE="-headers-only"
[ebuild  N     ] virtual/perl-Data-Dumper-2.160.0-r1
[ebuild  N     ] virtual/perl-Test-Harness-3.360.100_rc-r3
[ebuild  N     ] perl-core/File-Temp-0.230.400-r1
[ebuild  N     ] virtual/perl-File-Temp-0.230.400-r5
[ebuild  N     ] perl-core/File-Path-2.130.0
[ebuild  N     ] virtual/perl-File-Path-2.130.0
[binary   R    ] virtual/os-headers-0
[ebuild  N     ] sys-devel/autoconf-2.69-r4  USE="-emacs"
[ebuild  N     ] sys-apps/attr-2.4.47-r2  USE="-nls -static-libs"
[ebuild   R    ] sys-apps/coreutils-8.28-r1
[ebuild     U  ] app-admin/eselect-1.4.12 [1.4.8]
[ebuild     U  ] app-eselect/eselect-python-20171204 [20160516]
[ebuild     U  ] sys-devel/patch-2.7.6-r1 [2.7.5]
[ebuild  N     ] sys-apps/shadow-4.5  USE="cracklib xattr -acl -audit -nls -pam (-selinux) -skey"
[binary   R    ] virtual/shadow-0
[ebuild  N     ] virtual/perl-ExtUtils-MakeMaker-7.100.200_rc-r4
[ebuild  N     ] sys-libs/libcap-2.24-r2  USE="-pam -static-libs"
[ebuild  N     ] dev-perl/Text-Unidecode-1.270.0
[ebuild  N     ] dev-perl/libintl-perl-1.240.0-r2
[ebuild  N     ] sys-apps/help2man-1.47.4  USE="-nls"
[ebuild  N     ] sys-devel/automake-1.15.1-r2  USE="{-test}"
[ebuild  N     ] sys-devel/libtool-2.4.6-r3  USE="-vanilla"
[ebuild  N     ] dev-libs/expat-2.2.5  USE="unicode -examples -static-libs"
[ebuild   R    ] sys-process/psmisc-22.21-r3
[ebuild  N     ] sys-libs/gdbm-1.13-r2  USE="readline -berkdb -exporter -nls -static-libs"
[ebuild  N     ] sys-apps/groff-1.22.2  USE="-X -examples" L10N="-ja"
[ebuild  N     ] dev-libs/libelf-0.8.13-r2  USE="-debug -nls"
[ebuild  N     ] virtual/libelf-2
[ebuild  N     ] dev-libs/libgcrypt-1.8.1  USE="-doc -static-libs"
[ebuild  N     ] dev-perl/XML-Parser-2.440.0
[ebuild  N     ] virtual/perl-File-Spec-3.630.100_rc-r4
[ebuild  N     ] dev-perl/Unicode-EastAsianWidth-1.330.0-r1
[ebuild  N     ] sys-apps/texinfo-6.3  USE="-nls -static"
[ebuild  N     ] dev-libs/iniparser-3.1-r1  USE="-doc -examples -static-libs"
[ebuild  N     ] app-portage/portage-utils-0.64  USE="-nls -static"
[ebuild  N     ] dev-libs/openssl-1.0.2o  USE="asm sslv3 tls-heartbeat zlib -bindist -gmp -kerberos -rfc3779 -sctp -sslv2 -static-libs {-test} -vanilla"
[binary  N     ] dev-lang/python-2.7.14-r1  USE="ipv6 ncurses readline ssl (threads) (wide-unicode) xml (-berkdb) -build -doc -examples -gdbm -hardened -libressl -sqlite -tk -wininst"
[binary  N     ] sys-apps/openrc-0.34.11  USE="ncurses netifrc unicode -audit -debug -newnet -pam (-prefix) (-selinux) -static-libs" 
[ebuild  N     ] net-misc/netifrc-0.5.1
[binary   R    ] sys-apps/grep-3.0
[binary   R    ] sys-apps/findutils-4.6.0-r1
[binary   R    ] sys-apps/kbd-2.0.4
[ebuild  N     ] sys-apps/busybox-1.28.0  USE="ipv6 static -debug -livecd -make-symlinks -math -mdev -pam -savedconfig (-selinux) -sep-usr -syslog (-systemd)"
[binary   R    ] virtual/service-manager-0
[binary   R    ] sys-devel/binutils-2.29.1-r1
[ebuild  N     ] sys-apps/net-tools-1.60_p20161110235919  USE="arp hostname ipv6 -nis -nls -plipconfig (-selinux) -slattach -static" 
[binary   R    ] sys-apps/gawk-4.1.4
[binary   R    ] virtual/editor-0
[binary   R    ] sys-devel/make-4.2.1
[binary   R    ] sys-process/procps-3.3.12-r1
[binary   R    ] virtual/dev-manager-0-r1
[binary   R    ] sys-apps/which-2.21
[ebuild  N     ] net-misc/iputils-20171016_pre  USE="arping filecaps ipv6 openssl ssl -SECURITY_HAZARD -caps -clockdiff -doc -gcrypt
 (-idn) -libressl -nettle -rarpd -rdisc -static -tftpd -tracepath -traceroute"
[binary   R    ] virtual/pager-0
[binary   R    ] sys-apps/diffutils-3.5
[binary   R    ] sys-apps/baselayout-2.4.1-r2
[binary   R    ] virtual/libc-1
[binary   R   ~] sys-devel/gcc-7.3.0
[binary   R    ] virtual/pkgconfig-0-r1
[ebuild  N     ] dev-lang/python-3.5.5  USE="ipv6 ncurses readline ssl (threads) xml -build -examples -gdbm -hardened -libressl -sqlite {-test} -tk -wininst"
[ebuild  N     ] app-misc/ca-certificates-20170717.3.36.1  USE="-cacert -insecure_certs"
[ebuild  N     ] sys-apps/util-linux-2.30.2-r1  USE="cramfs ncurses readline suid unicode -build -caps -fdformat -kill -nls -pam -python (-selinux) -slang -static-libs (-systemd) {-test} -tty-helpers -udev" PYTHON_SINGLE_TARGET="python3_5 -python2_7 -python3_4 -python3_6" PYTHON_TARGETS="python2_7 python3_5 -python3_4 -python3_6"
[ebuild     U  ] app-misc/pax-utils-1.2.3 [1.1.7]
[ebuild     U  ] sys-apps/sandbox-2.13 [2.10-r4]
[ebuild     U  ] net-misc/rsync-3.1.3 [3.1.2-r2]
[ebuild  N     ] net-firewall/iptables-1.6.1-r3  USE="ipv6 -conntrack -netlink -nftables -pcap -static-libs"
[ebuild     U  ] dev-libs/libpipeline-1.4.2 [1.4.0]
[ebuild  N     ] sys-apps/man-db-  USE="gdbm manpager zlib -berkdb -nls (-selinux) -static-libs"
[ebuild     U  ] sys-apps/kmod-24 [23] PYTHON_TARGETS="-python3_6%"
[ebuild  N     ] dev-python/pyblake2-1.1.0  PYTHON_TARGETS="python2_7 python3_5 (-pypy) -python3_4 -python3_6"
[ebuild  N     ] net-misc/openssh-7.5_p1-r4  USE="hpn pie ssl -X -X509 -audit -bindist -debug -kerberos -ldap -ldns -libedit -libressl -livecd -pam -sctp (-selinux) -skey -ssh1 -static {-test}"
[ebuild  N     ] dev-util/gtk-doc-am-1.25-r1
[ebuild  N     ] dev-libs/libxml2-2.9.7  USE="ipv6 readline -debug -examples -icu -lzma -python -static-libs {-test}" PYTHON_TARGETS="python2_7 python3_5 -python3_4 -python3_6"
[ebuild  N     ] sys-devel/gettext-  USE="cxx ncurses openmp -acl -cvs -doc -emacs -git -java (-nls) -static-libs"
[ebuild  N     ] app-text/build-docbook-catalog-1.19.1
[ebuild  N     ] dev-libs/libxslt-1.1.30-r2  USE="crypt -debug -examples -python -static-libs" PYTHON_TARGETS="python2_7"
[ebuild  N     ] app-text/docbook-xsl-stylesheets-1.79.1-r2  USE="-ruby"
[ebuild  N     ] app-text/docbook-xml-dtd-4.1.2-r6
[ebuild  N     ] dev-util/intltool-0.51.0-r2
[ebuild  N     ] dev-libs/glib-2.52.3  USE="mime xattr -dbus -debug (-fam) (-selinux) -static-libs -systemtap {-test} -utils" PYTHON_TARGETS="python2_7"
[ebuild  N     ] x11-misc/shared-mime-info-1.9  USE="{-test}"
[ebuild  N     ] dev-python/setuptools-36.7.2  USE="{-test}" PYTHON_TARGETS="python2_7 python3_5 (-pypy) (-pypy3) -python3_4 -python3_6"
[ebuild  N     ] dev-python/certifi-2017.4.17  PYTHON_TARGETS="python2_7 python3_5 (-pypy) (-pypy3) -python3_4 -python3_6"
[ebuild  N     ] dev-python/pyxattr-0.5.5  USE="-doc {-test}" PYTHON_TARGETS="python2_7 python3_5 (-pypy) -python3_4"
[ebuild  N     ] sys-apps/portage-2.3.24-r1  USE="(ipc) native-extensions xattr -build -doc -epydoc -gentoo-dev (-rsync-verify) (-selinux)" PYTHON_TARGETS="python2_7 python3_5 (-pypy) -python3_4 -python3_6"
[ebuild  N     ] app-admin/perl-cleaner-2.25
[binary   R    ] virtual/man-0-r1
[binary   R    ] virtual/modutils-0
[ebuild  N     ] sys-fs/e2fsprogs-1.43.6  USE="-fuse (-nls) -static-libs"
[ebuild     U  ] virtual/package-manager-1 [0]
[ebuild  N     ] sys-apps/iproute2-4.14.1-r2  USE="iptables ipv6 -atm -berkdb -minimal (-selinux)"
[binary   R    ] virtual/ssh-0
[ebuild  N     ] net-misc/wget-1.19.1-r2  USE="ipv6 pcre ssl zlib -debug -gnutls -idn -libressl -nls -ntlm -static {-test} -uuid"
[ebuild   R    ] dev-util/pkgconfig-0.29.2  USE="-internal-glib*"

!!! The following binary packages have been ignored due to non matching USE:

    =dev-util/pkgconfig-0.29.2 internal-glib
    =sys-apps/attr-2.4.47-r2 nls
    =sys-apps/man-db- nls
    =dev-libs/libelf-0.8.13-r2 nls
    =sys-apps/shadow-4.5 -linguas_cs -linguas_da -linguas_de -linguas_es -linguas_fi -linguas_fr -linguas_hu -linguas_id -linguas_it -linguas_ja -linguas_ko -linguas_pl -linguas_pt_BR -linguas_ru -linguas_sv -linguas_tr -linguas_zh_CN -linguas_zh_TW nls

NOTE: The --binpkg-respect-use=n option will prevent emerge
      from ignoring these binary packages if possible.
      Using --binpkg-respect-use=y will silence this warning.

I think that’s broken the back of the job.  Of course when I come to running Catalyst, I’ll have to do it all over again, but at least now the environment is clean.

Apr 282018

So, a few weeks ago I installed a new battery charger, and tweaked it so that the solar did most of the leg work during the day, and the charger kept the batteries topped up at night.

I also discussed the addition of a new industrial PC to perform routing and system monitoring functions… which was to run Gentoo Linux/musl. For now, that little PC is still running Debian Stretch, but for 45 days, it was rock solid. The addition of this box, and taking on the role of router to the management network meant I could finally achieve one of my long-term goals for the project: decommissioning the old server.

The old server is still set up with all my data and software… but now the back-up cron job calls /sbin/poweroff when it’s done, and the BIOS is set to wake the machine up in the evening ready to receive a back-up late at night.

In its place, a virtual machine clone of the box, handles my email and all the old functions of that server. This was all done just prior to my father and I leaving for a 3 week holiday in the Snowy Mountains.

I did have a couple of hiccups with Ceph OSDs crashing … but basically re-starting the daemons (done remotely whilst travelling through Cowra) got everything back up. A bit of placement group cleaning, and everything was back online again. I had another similar hiccup coming out of Maitland, but once again, re-starting the daemons fixed it. No idea why it crashed, that’s something I’ll have to investigate.

Other than that, the cluster itself has run well.

One thing that did momentarily kill the industrial PC though: I wandered down to the rack with a small bus-powered 2.5″ HDD with the intent of re-starting my Gentoo builds. This HDD had the same content as the 3.5″ HDD I had plugged in before. I figured being bus powered, I would not be dependent on mains, and it could just chug away to its heart’s content.

No such luck, the moment I plugged that drive in, the little machine took great umbrage to the spinning rust now vacuuming the electrons away from its core functions, and shut down abruptly. I’ve now brought my 3.5″ drive and dock down, plugged that into the wall, and have my builds resuming. If power goes off, hopefully the machine either handles the loss of swap gracefully. If it does crash, the watchdog will take care of it.

Thus, I have the little TS-7670 first attempting a build of gcc, to see how we go. Finger’s crossed our power should remain up. There was at least one outage in the time we were away, but hopefully we should get though this next build!

The next step I think should be to add some control of the mains charger to allow the batteries to be boosted to full charge overnight. The thinking is a simple diode-OR arrangement. Many comparators such as the LM393 have an open-collector output, which gives us this for free.

The theory is this.

The battery bank powers a simple circuit which runs of a 5V regulator. That regulator powers a dual comparator IC and provides a reference voltage. The comparator draws bugger all power, so I’m happy to use a linear PSU here. It’s mainly there as a voltage reference.

Precision isn’t really the aim here, so adjustable pots will make life easier.

The voltages from the battery bank and the solar panel are fed through voltage dividers to bring the voltages down to below 5V, then those voltages are individually fed into separate pots that control the hysteresis. I can adjust all points of the system.

The idea is that should the batteries get too low, or the sun go down, one or the other (or both) comparators will go low and pull down on R2. If the batteries are high and the sun is up, nothing pulls on R2 so the REMOTE+ pin on the HEP-600C-12 is allowed to float to +5V, turning off the mains charger.

The advantage of this is there’s no programming of a microcontroller, it’s just analogue electronics. The LM393s are pretty hardy things, the datasheet says they’ll run at 36V and can accept a maximum voltage of VCC-1.5V; so if I run at 5V, 3.5V is my recommended maximum. The adjustment pots should let me set a threshold voltage that avoids going above this.

I mainly need 5V for the HEP-600C-12, and for providing that stable known voltage reference. The LM78C05 should be fine for this.

Once I’ve done that, I should be able to wind that charger back up to its factory setting of 14.4V, which will mean that overnight the batteries will be charged back to full charge.

Mar 152018

Perhaps literally… it has bitten the dust.  Although I wouldn’t call its installed location, dusty.  Once again, the fan in the mains power supply has carked it.

Long-term followers of this project may remember that the last PSU failed the same way.

The reason has me miffed.  All I did with the replacement, was take the PSU out of its box, loosen the two nuts for the terminals, slip the ring lugs for my power lead over the terminals, returned the nuts, plugged it in and turned it on.

While it is running 24×7, there is nothing in the documentation to say this PSU can’t run that way.  This is what the installation looks like.

If it were dusty, I’d expect to be seeing hardware failures in my nodes.

This PSU is barely 4 months old, and earlier this week, the fan started making noises, and requiring percussive maintenance to get started. Tonight, it failed. Completely, no taps on the case will convince it to go.

Now, I need to keep things running until the weekend. I need it to run without burning the house down.

Many moons ago, my father bought a 12V fan for the caravan. Cheap and nasty. It has a slider switch to select between two speeds; “fast” and “slow”, which would be better named “scream like a banshee” and “scream slightly less like a banshee”. The speed reduction is achieved by passing current through a 10W resistor, and achieves maybe a 2% reduction in motor RPM. As you can gather, it proved to be a rather unwelcome room mate, and has seen its last day in the caravan.

This fan, given it runs off 12V, has proven quite handy with the cluster. I’ve got my SB-50 “load” socket hanging out the front of the cluster. A little adaptor to bring that out to a cigarette lighter socket, and I can run it off the cluster batteries. When a build job has gotten a node hot and bothered, sitting this down the bottom of the cluster and aiming it at a node has cooled things down well.

Tonight, it has another task … to try and suck the hot air out of the PSU.

That’s the offending power supply.  A PowerTech MP-3089.  It powers the RedARC BCDC-1225 right above it.  And you can see my kludge around the cooling problem.  Not great, but it should hold for the next 24 hours.

Tomorrow, I think we’ll call past Aspley and pick up another replacement.  I’m leery of another now, but I literally have no choice … I need it now.  Sadly, >250W 12V switchmode PSUs are somewhat rare beasts here in Brisbane.  Altronics don’t sell them that big.  The grinning glasses are no more, and I’m not risking it with the Xantrex charger again.

Long term, I’m already looking at the MeanWell SP-480-12.  This is a PSU module, and will need its own case and mains wiring… but I have no faith in the MP-3089 to not fail and cremate my home of 34 years.

The nice feature of the SP-480-12 is that it does have a remote +12V power-off feature.  Presumably I can drive this with a comparator/output MOSFET, so that when the battery voltage drops below some critical threshold, it kicks in, and when it rises above a high set-point, it drops out.  Simple control, with no MCU involved.  I don’t see a reason to get more fancy than that on the control side, anything more is a liability.

On other news, my gcc build on the TS-7670 failed … so much for the wait.  We’ll try another version and see how we go.

Mar 122018

Well, in my last post I discussed getting OpenADK to build a dev environment on the TS-7670.  I had gotten Gentoo’s Portage installed, and started building packages.

The original plan was to build everything into /tmp/seed, but that requires that all the dependencies are present in the chroot.  They aren’t.  In the end, I decided to go the ill-advised route of compiling Gentoo over the top of OpenADK.

This is an ugly way to do things, but it so far is bearing fruit.  Initially there were some hiccups, and I had to restore some binaries from my OpenADK build tree.  When Gentoo installed python-exec; that broke Portage and I found I had to unpack a Python 2.7 binary I had built earlier then use that to re-install Portage.  I could then continue.

Right now, it’s grinding away at gcc; which was my nemesis from the beginning.  This time though, it successfully built xgcc and xg++; which means it has compiled itself using the OpenADK-supplied gcc; and now is building itself using its self-built binaries.  I think it does two or three passes at this.

If it gets through this, there’s about 65 packages to go after that.  Mostly small ones.  I should be able to do a ROOT=/tmp/seed emerge -ek @system then tar up /tmp/seed and emerge catalyst.  I have some wrapper scripts around Catalyst that I developed back when I was responsible for doing the MIPS stages.  These have been tweaked to do musl builds, and were used to produce these x86 stages.  The same will work for ARMv5.

It might be another week of grinding away, but we should get there. 🙂

Jan 292018

So, fun and games with the TS-7670.

At present, I have it up and running:

root@ts7670:~# uname -a
Linux ts7670 4.14.15-vrt-ts7670-00031-g1a006273f907-dirty #2 Sun Jan 28 20:21:08 EST 2018 armv5tejl GNU/Linux

That’s booted up into Debian Stretch right now.  debootstrap did its deed a few days ago on the eMMC, and I was able to boot up this new image.  Today I built a new kernel, and tweaked U-Boot to boot from eMMC.

Thus now the unit can boot without any MicroSD cards fitted.

There’s a lot of bit rot to address.  U-Boot was forked from some time in 2014.  I had a crack at rebasing the code onto current U-Boot, but there’s a lot of clean-up work to do just to get it to compile.  Even the kernel needed some fixes to get the newer devicetree sources to build.

As for getting Gentoo working… I have a cross-compiling toolchain that works.  With it, I’ve been able to compile about 99% of a seed stage needed for catalyst.  The 1% that eludes me, is GCC (compiled to run on ARMv5).  GCC 4.9.4 will try to build, but fails near the end… anything newer will barf complaining that my C++ compiler is not working.  Utter bollocks, both AMD64 and ARM toolchains have working C++ compilers, just it’s looking for a binary called “g++” rather than being specific about which one.  I suspect it wants the AMD64 g++, but then if I symlink that to /usr/bin/g++, it throws in ARM CFLAGS, and AMD64 g++ barfs on those.

I’ve explored other options.  I can compile GCC by hand without C++ support, and this works, but you can’t build modern GCC without a C++ compiler … and people wonder why I don’t like C++ on embedded!

buildroot was my next thought, but as it happens, they’ve stripped out the ability to compile a native GCC on the target.

crosstool-ng is the next logical choice, but I’ll have to fiddle with settings to get the compiler to build.

I’ve also had OpenADK suggested, which may be worth a look.  Other options are OpenEmbedded/Yocto, and Cross Linux from Scratch.  I think for the latter, cross is what I’ll get, this stuff can be infuriatingly difficult.

Jan 232018

So, last time I was trying to get Gentoo’s portage to cross-build gcc so that I’d have a C/C++ compiler in my ARMv5 musl environment.

It is literally the last piece of the puzzle.  Once compiled, that is the last step I need before I can throw the shiny new environment onto an ARMv5 VM (or real ARMv5 CPU), do an emerge -e world on it then tar the lot up and throw it at Catalyst.

Building an entire OS on a 454MHz ARMv5 machine with 128MB RAM does not faze me one bit… I used to do it regularly on a (Gateway-branded) Cobalt Qube II server appliance, which sports a 250MHz QED RM5231 and 128MB RAM.  The other compile workhorse I used in those days was an SGI O2; 300MHz RM5200, again 128MB RAM.

Yes, Linux and its userland has bulked up a bit in the last 10 years, but not so much so that a build on these is impossible.

Certainly, native building is easier than cross-compiling.  Cross-compilers have always been a voodoo art for me.  Getting one that will build a Linux kernel or U-Boot, usually isn’t too hard… but get userland involved and it gets complex.  Throw in C++ and complexity skyrockets!

I’m taking OpenADK for a spin now, and in concept, it’s exactly what I remember buildroot used to be.  It’s a tool for generating a fully fledged embedded Linux system with a wide package selection including development tools.  I also find that you have to hold your tongue just right to get stuff to compile.

Selecting a generic arm926ej-s; it succeeded to build a x86-64 hosted cross-toolchain once, but then silently refused to build anything else.  I told it instead to build for a Versatile PB with an arm926ej-s CPU… it failed to build the cross-toolchain, even though it pretty much is the exact same target.

A make cleandirs later, and it happily started building everything, but then hiccupped on permissions, so against my better judgement, I’m running it now with sudo, and things are progressing.  With some luck, I should have something that will give me a working native gcc/g++ for musl on ARMv5.

Jul 172016

A little trick I just learned today. First, the scenario.

I have a driver for a USART port, the USART on the ATMega32U4 in fact. It uses a FIFO interface to represent the incoming and outgoing data.

I have a library that also uses a FIFO to represent the data to be sent and received on a USART.

I have an application that will configure the USART and pipe between that and the library.

Now, I could have each component implement its own FIFOs, and have the main application shovel data between them. That could work. But I don’t want to do this. I could have the user pass in a pointer to the FIFOs in initialisation functions for the USART driver and the library, but I don’t want to store the extra pointers or incur the additional overheads.

Turns out, you can define a symbol somewhere, then alias it to make two variables appear in the same place. This is done with the alias attribute, and it requires that the target is defined with the nocommon attribute.

In the USART driver, I’ve simply declared the FIFOs as extern entities. This tells the C compiler what to expect in terms of data type but does not define a location in memory. Within the driver, use the symbols as normal.

/* usart.h */

/*! FIFO buffer for USART receive data */
extern struct fifo_t usart_fifo_rx;

/*! FIFO buffer for USART transmit data */
extern struct fifo_t usart_fifo_tx;

/* usart.c */
static void usart_send_next() {
  /* Ready to send next byte */
  int16_t byte = fifo_read_one(&usart_fifo_tx);
  if (byte >= 0)
    UDR1 = byte;

ISR(USART1_RX_vect) {
  fifo_write_one(&usart_fifo_rx, UDR1);

I can do the same for the protocol library.

/* External FIFO to host UART */
extern struct fifo_t proto_host_uart_rx, proto_host_uart_tx;

/*! External FIFO to target UART */
extern struct fifo_t proto_target_uart_rx, proto_target_uart_tx;

Now how do I link the two? They go by different names. I create aliases, that’s how.

 * FIFO buffers for target communications.
static struct fifo_t target_fifo_rx __attribute__((nocommon));
static uint8_t target_fifo_rx_buffer[128];
extern struct fifo_t usart_fifo_rx __attribute__((alias ("target_fifo_rx")));
extern struct fifo_t proto_target_uart_rx __attribute__((alias ("target_fifo_rx")));

static struct fifo_t target_fifo_tx __attribute__((nocommon));
static uint8_t target_fifo_tx_buffer[128];
extern struct fifo_t usart_fifo_tx __attribute__((alias ("target_fifo_tx")));
extern struct fifo_t proto_target_uart_tx __attribute__((alias ("target_fifo_tx")));

 * FIFO buffers for host communications.
static struct fifo_t host_fifo_rx __attribute__((nocommon));
static uint8_t host_fifo_rx_buffer[128];
extern struct fifo_t proto_host_uart_rx __attribute__((alias ("host_fifo_rx")));
static struct fifo_t host_fifo_tx __attribute__((nocommon));
static uint8_t host_fifo_tx_buffer[128];
extern struct fifo_t proto_host_uart_tx __attribute__((alias ("host_fifo_tx")));

Now a quick check with nm should reveal these to all be at the same locations:

RC=0 stuartl@vk4msl-mb ~/projects/debugwire/firmware $ avr-nm leodebug.elf \
     | grep '\(proto_.*_uart_.x\|host_fifo_.x\|target_fifo_.x\)'
0080022c b host_fifo_rx
008001ac b host_fifo_rx_buffer
0080019c b host_fifo_tx
0080011c b host_fifo_tx_buffer
0080022c B proto_host_uart_rx
0080019c B proto_host_uart_tx
0080034c B proto_target_uart_rx
008002bc B proto_target_uart_tx
0080034c b target_fifo_rx
008002cc b target_fifo_rx_buffer
008002bc b target_fifo_tx
0080023c b target_fifo_tx_buffer