Installing uHal/IPBus in 2021
Of course things have changed. See:
https://ipbus.web.cern.ch/doc/user/html/software/install/compile.html
There was some issue with broken symlinks in /usr/lib/erlang/man/man1
. Find them with:
$ find ./ -type l -exec file {} \; |grep broken
Then remove them by hand.
Dan says one must use the following extra flags for things to work with BUTool:
$ make -j 6 LDFLAGS="-Wl,--no-as-needed"
Installing uHal/IPBus in 2020
I'm working to install everything on Ubuntu 20.04. Seems straightforward (ha!)
$ sudo apt install python3-pip $ export PATH=${PATH}:/home/hazen/.local/bin $ sudo apt-get install make erlang g++ libboost-all-dev libpugixml-dev python-all-dev $ git clone --depth=1 -b v2.7.9 https://github.com/ipbus/ipbus-software.git $ cd ipbus-software $ make |& tee build_log.txt # (note to self: use '-j 8' next time!)
OK, it's failing a lot with 'python not found'.
$ which python $ # hmm, no answer $ sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 1 $ sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 2 $ which python /usr/bin/python # ok, good $ python --version Python 3.8.5
Re-run make, all seemingly good now.
$ sudo make install
Older Notes (maybe still relevant)
The uHAL / IPBus software+firmware package (source) provides a convenient way to read/write registers and memories on a hardware device. The original use case was to access programmable logic (FPGAs) on a board connected to a computer over Ethernet.
The software component (uHAL) queues requested operations (read and write) in a "packet" which is transmitted to the hardware device when a dispatch function is called. The firmware component (IPBus) parses the packet and performs the requested read and write operations in a logical 32-bit address space using a proprietary local bus (similar to Wishbone).
A key feature of the package is the address table which is represented by one or more XML files. Typically an address table names registers as in the following example:
<node id="REG" address="0x0001" permission="rw"> <node id="REG_TOP" mask="0xffff0000"/> <node id="REG_BOT" mask="0x0000ffff"/> </node> <node id="RESETS" address="0x0002" permission="w"> <node id="RST_ALL" mask="1"/> <node id="RST_LINKS" mask="2"/> </node>
A bit of sample code taken from the tutorial illustrates the key points:
ConnectionManager manager("file://path/to/connections.xml"); HwInterface hw = manager.getDevice("dummy.udp.0"); //write 1 in the address 0x0001 hw.getNode ("REG").write(1); //read back ValWord< uint32_t > reg = hw.getNode ("REG").read(); //send the IPbus transactions hw.dispatch(); std::cout << "REG = " << reg.value() << std::endl;
This code illustrates the typical use case, where one performs reads/writes on entire 32-bit registers using names from the address table. In addition, the address table can contain a mask, which can be used to read or write subsets of bits from a register. However one must be careful, as the protocol only supports full 32-bit reads and writes. Writing a masked value actually causes a read/modify/write which may not be what is desired.
Often we find that we want to do other things which are not trivially supported by uHAL, such as:
- Read/write to numeric addresses
- Read/write to an offset within a named region
- Write a fixed set of bits to a register with no read
All these things can be accomplished, but require some cleverness. To access the numeric address of a register, one can use the following code snippet:
addr = hw.getNode( "rx_buffer").getAddress();
To access an offset from a named register, one must resort to some slightly more intricate code:
val = hw.getClient().read( hw.getNode("rx_buffer").getAddress() + offset);
To write a single bit to e.g. a reset register as shown in the address table above, one can use the following:
mask = hw.getNode( "RST_ALL"). getMask(); hw.getClient().write( hw.getNode("RST_ALL").getAddress(), mask);