Author: Lewis, J.H.
Paper Title Page
WEBHMULT03 EtherBone - A Network Layer for the Wishbone SoC Bus 642
  • M. Kreider, W.W. Terpstra
    GSI, Darmstadt, Germany
  • J.H. Lewis, J. Serrano, T. Włostowski
    CERN, Geneva, Switzerland
  Today, there are several System on a Chip (SoC) bus systems. Typically, these busses are confined on-chip and rely on higher level components to communicate with the outside world. Taking these systems a step further, we see the possibility of extending the reach of the SoC bus to remote FPGAs or processors. This leads to the idea of the EtherBone (EB) core, which connects a Wishbone (WB) Ver. 4 Bus via a Gigabit Ethernet based network link to remote peripheral devices. EB acts as a transparent interconnect module towards attached WB Bus devices. Address information and data from one or more WB bus cycles is preceded with a descriptive header and encapsulated in a UDP/IP packet. Because of this standard compliance, EB is able to traverse Wide Area Networks and is therefore not bound to a geographic location. Due to the low level nature of the WB bus, EB provides a sound basis for remote hardware tools like a JTAG debugger, In-System-Programmer (ISP), boundary scan interface or logic analyser module. EB was developed in the scope of the WhiteRabbit Timing Project (WR) at CERN and GSI/FAIR, which employs GigaBit Ethernet technology to communicate with memory mapped slave devices. WR will make use of EB as means to issue commands to its timing nodes and control connected accelerator hardware.  
slides icon Slides WEBHMULT03 [1.547 MB]  
THCHMUST04 Free and Open Source Software at CERN: Integration of Drivers in the Linux Kernel 1248
  • J.D. González Cobas, S. Iglesias Gonsálvez, J.H. Lewis, J. Serrano, M. Vanga
    CERN, Geneva, Switzerland
  • E.G. Cota
    Columbia University, NY, USA
  • A. Rubini, F. Vaga
    University of Pavia, Pavia, Italy
  We describe the experience acquired during the integration of the tsi148 driver into the main Linux kernel tree. The benefits (and some of the drawbacks) for long-term software maintenance are analysed, the most immediate one being the support and quality review added by an enormous community of skilled developers. Indirect consequences are also analysed, and these are no less important: a serious impact in the style of the development process, the use of cutting edge tools and technologies supporting development, the adoption of the very strict standards enforced by the Linux kernel community, etc. These elements were also exported to the hardware development process in our section and we will explain how they were used with a particular example in mind: the development of the FMC family of boards following the Open Hardware philosophy, and how its architecture must fit the Linux model. This delicate interplay of hardware and software architectures is a perfect showcase of the benefits we get from the strategic decision of having our drivers integrated in the kernel. Finally, the case for a whole family of CERN-developed drivers for data acquisition models, the prospects for its integration in the kernel, and the adoption of a model parallel to Comedi, is also taken as an example of how this model will perform in the future.  
slides icon Slides THCHMUST04 [0.777 MB]