Hi, this is the announcement of my userspace master code, according to my plans explained in http://lists.etherlab.org/pipermail/etherlab-dev/2014/000437.html
Download, installation and usage instructions can be found on my web site at http://fh-soft.de/src/ethercat-userspace.html I hope you don't mind me sending my announcement to this list. But it also contains some patches that may be interesting for the original IgH master code (see below). Further discusssion which is not related to the IgH master code should be continued by private mail. The whole porting was almost easier than I had anticipated. I could follow my roadmap (as detailed in the mail above) 100%. Almost the only unexpected problem (aside from some minor issues mostly found by compiler warnings, see e30-cleanup.patch) was that I had to increase EC_IO_TIMEOUT from 500 to 2000 (microseconds). And even that shouldn't have been unexpected since this is exactly the timing I had planned and tested for anyway (for PDOs); I just hadn't been aware of this hard timeout for SDOs. So increasing it was no problem. With our application at 500Hz we did not observe any packet loss (including timeouts) over the course of several hours. On a faster development machine (8*i7), we could even increase the frequency to 2kHz without packet loss during a test of several minutes, and 4kHz with only sporadic packet loss. (But this won't be our production machine, unfortunately. ;) This was all done on a standard Debian wheezy kernel, without CONFIG_PREEMPT set, but of course using soft realtime and CPU affinity. As planned, I replaced the cdev ioctl with a simple TCP protocol that encapsulates the former ioctl data. This makes it possible (in fact almost trivial) to access it from a remote host. Therefore I added a new option "--host" to the "ethercat" tool. One could do the same to lib easily, but I didn't do it yet, since the value of running an application remotely seems questionable. (In fact I don't use lib myself, and with the userspace master, there might be little purpose to it at all, since the main application runs in userspace already, with less communication overhead. lib would be useful to run several applications on the same master simultaneously. Whether or not that's useful to someone, I kept lib because it was almost trivial to do.) I built the code as a deb package, because Debian is the system I use, and because the preferred way for source deb packages is to have unmodified original sources plus a set of patches which are applied during the build process. This matches exactly what I had done before anyway. However, this doesn't mean the code will only work on Debian; my web site contains build instructions for other Linux systems. So all changes I made to the sources are contained in the debian/patches directory of http://fh-soft.de/deb/ethercat-userspace_1.5.0-1.debian.tar.gz (The remaining files in this archive, as well as ethercat-userspace_1.5.0-1.dsc, are rather standard deb packaging stuff, not needed unless you want to build deb packages. ethercat-userspace_1.5.0.orig.tar.bz2 is exactly the original IgH EtherCAT-Master 1.5.0 release as downloaded from http://etherlab.org/download/ethercat/ethercat-1.5.0.tar.bz2 just renamed as required by deb package requirements). The first few patches (starting with "e") should be generally useful for the kernel master code as well, and you can apply them whether or not you care about the userspace master: - e02-*.patch .. e29-*.patch These are exactly my previous patches (from the attachment in http://lists.etherlab.org/pipermail/etherlab-dev/2014/000404.html), though renamed from NN-ethercat-1.5-DESC.patch to eNN-DESC.patch - e30-cleanup.patch Some bug fixes (e.g. type errors) and cleanup (e.g. removal of unused variables) that I encountered while building on a 64 bit system and with higher warning options. It seems Knud's patches contain some of the same; well, that's the price of forked development. - e31-open-master.patch Make the ecrt_open_master() function also available for the (so far kernel) master application (not only for the lib). It's useful to access the master to wait for the bus scan to complete and the SDO dictionaries to be fetched, before calling ecrt_request_master() which already starts the operation thread. Before, I had used an external script which used the ethercat tool to do the waiting, but it was already a bit awkward, and would become even more so when the application runs with the user space master. I see no reason not to make this function available, so I did it instead of writing a cumbersome workaround. - e32-request-master-check-device.patch In ecrt_request_master(), verify that the master actually has a device attached, just like ecrt_open_master() does. - e33-errno.patch struct ec_sdo_request contains a field called errno which is a bit unfortunate since system headers may define errno as a macro (for thread support). Of course, this doesn't matter in kernel code which doesn't use those headers, but I'd still suggest to change it. I simply renamed it to "errno_" here. Of course, any other name would be fine, too. - e34-manpage.patch Add a man page (as required by deb packages) for the ethercat tool, auto-generated with the "help2man" tool. Add a "--version" option (required by help2man) to the tool. Note: Applying this patch will add a dependency on help2man which is widely available. But if this seems like a problem, it could be checked for by configure (there are examples to do this out there). - e35-pkg-config.patch Add a .pc file for libethercat, so it can be used with pkg-config. Note: pkg-config is not required for building (the file is generated with simple variable subtitutions), and using it for the installed library is entirely optional, so applying this patch doesn't add any dependencies. The following patches contain changes specifially for userspace master support, though they don't actually change the behaviour yet. If you care about userspace support, you could apply them without breaking the kernel master (though they provide no benefit to it either): - u01-ioctl.patch Split the ioctl calls from lib and tool into three groups (ioctl_noarg (no argument), ioctl_value (just a single integer argument), and ioctl_typed (integer argument and some data structure)), as will be required by the emulation below. This is a boring patch that just replaces ioctl() with 3 other names and in the end #defines them all back to ioctl(), so it doesn't change the behaviour yet. - u02-emulation.patch Emulation for the kernel headers used by the master code. These are partly dummy headers, partly copied from actual kernel headers (where there are no actual kernel dependencides, especially list.h) and partly replacement functions written for this purpose. This patch just adds some files in a new directory emulation/linux/ which is not referenced from anywhere, so it doesn't change the behaviour yet. - u03-master-in-userspace.patch This patch contains the actual changes necessary for the userspace master (in master/ and devices/generic.c). As stated in my announcement, I tried to put most of them in the emulation (see previous patch), but a few changes were still necessary. It also adds the new ecrt_init() and ecrt_done() functions as well as ethercat_master.c (see "Usage" for all of them) and, in cdev.c, a thread (per master) to provide a TCP based emulation for the ioctl calls. The patch also contains changes to lib/ and tool/ to use the emulation to access the master. (The actual emulation code is in master/ioctl.h, together with the master-side code for easier maintenance.) All relevant changes are #ifdef'ed EC_MASTER_IN_USERSPACE which is not defined anywhere, so it doesn't change the behaviour yet. The last patch finally changes the behaviour: - build-userspace.patch This patch only contains changes to Makefiles and configure to avoid building kernel code, as well as examples/ and script/, and instead build the userspace master, using -Iemulation/ and defining EC_MASTER_IN_USERSPACE as required. Someone who is better versed in autotools than I am might even be able to arrange things so both versions can be built together. This would require building the master twice, of course, but also lib/ and tool/ (once with ioctl and once with the TCP emulation), or else add a runtime switch to them so the same code will work with both versions of the master (which actually shouldn't be so hard). Though I don't know if anyone has any use for this -- you probably want to use either the kernel or the userspace master, not both at the same time ... Regards, Frank -- Dipl.-Math. Frank Heckenbach <f.heckenb...@fh-soft.de> Stubenlohstr. 6, 91052 Erlangen, Germany, +49-9131-21359 Systems Programming, Software Development, IT Consulting _______________________________________________ etherlab-dev mailing list etherlab-dev@etherlab.org http://lists.etherlab.org/mailman/listinfo/etherlab-dev
