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Linux EPICS IOC Support Industry Pack and Stepper Motor Status Report EPICS Meeting at IHEP

August 2002 Marty Kraimer. Linux EPICS IOC Support Industry Pack and Stepper Motor Status Report EPICS Meeting at IHEP. Overview. First presented at EPICS meeting at BESSY in May 2002 Describes work in progress to support Linux PC IOCs First Target Applications:

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Linux EPICS IOC Support Industry Pack and Stepper Motor Status Report EPICS Meeting at IHEP

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  1. August 2002 Marty Kraimer Linux EPICS IOC SupportIndustry Pack and Stepper MotorStatus ReportEPICS Meeting at IHEP

  2. Overview • First presented at EPICS meeting at BESSY in May 2002 • Describes work in progress to support Linux PC IOCs • First Target Applications: • Synchrotron Beam line Applications • Working with Tim Mooney's group at APS • Some APS/ASD (Accelerator) Applications • Example: Monitoring Conventional Facility data • First Hardware Support • OMS PCI Motor support (Joe Sullivan from Tim Mooney's group) • PCI Industry Pack Carrier • Serial, gpib, adc, dac, digital I/O.

  3. VISION • LINUX REPLACES VXWORKS • BUT: Linux isn’t a real time operating system • Non-pre-emptive kernel => no context switch while kernel active. • Interrupts can be disabled for long periods of time. • Worst case can be 100s milliseconds. (2.4 Kernel) • Future • Development kernel is pre-emptive. • Work in progress so that interrupts disabled for short times. • Other possibilities • RTLinux • RTAI • RTEMS

  4. Modified VISION • Existing Linux good enough for some Applications. • 2.6 Kernel will be good enough for more Applications. • If small part of Application needs strict real time. • Use RTLinux/RTAI. • For demanding Apps use RTEMS or stay with vxWorks. • RTEMS • Open Source • Tests show real time performance equivalent to vxWorks • Not as complete an environment as vxWorks • Well supported by R3.14 • Eric Norum and Till Straumann are very interested in it. • See EPICS 3.14 home page and Till's talk at BESSY EPICS meeting.

  5. Initial Goals • Industry Pack Support on Linux IOCs • Standard PC platforms original goal • In the future • CompactPCI • Other platforms, eg. VME • Work with Tim Mooney’s group (synApps) • Joe Sullivan working on PCI based motor support. • IP + Motor => usable for some beam line applications. • Expect there will be a lot of interest. • Requires Message Passing Facility (MPF) • When IP+Motor support ready some synApps can be done.

  6. Industry Pack Support • Industry Pack: Small Low Cost I/O Modules • PCI40A IP Carrier: SBS GreenSpring Modular I/O • PCI bus card that holds four IP modules • Fits in standard PCI slot. • MPF and synApps supports following IP modules: • SBS IP Octal Serial: eight serial ports • SBS IP488: GPIB interface • SBS Ip-uniDig: family of Digital I/O modules • Acromag IP330: ADC; 16 bit ; 16 channel DI or 32 channel SE • Systran DAC128: DAC; 8 channel; 12 bit DAC • Goal is to support all of this on Linux

  7. Progress • Linux Kernel support now exists for • Generic IP carrier support (Like ANJs IPAC support) • PCI-40A: SBS Quad IP Carrier for PCI Bus • IP-488 (Green Springs GPIB IP using the ti9914) • IP-Serial (Green Springs IP-Octal) • Simple driver for OMS PCI Motor driver (Proof of Concept only) • Message Passing Facility (MPF) ported to 3.14 • Lots of cleanup. • Ran several tests successfully • Still at preAlpha stage • Gpib and Serial still very buggy!! • No Documentation

  8. Implementation Strategy • Clear Separation between Linux and EPICS • Linux drivers have NO knowledge of EPICS • Separate development area. Separate releases. • Usable by non-EPICS and non-MPF users • Linux char drivers (ioctl calls heavily used) • Drivers written with real time performance goal • Allow complete transaction with single user level call • Read, write, writeRead typical request • Allow easy addition of code called by interrupt handlers • For now testing with ordinary user level process • Later will test using real time scheduling • Will try multi-priority iocCore (existing 3.14 does not do this)

  9. PCI40A Support • Generic IP Carrier Support • Similar to what Andrew Johnson did for drvIpac • The PCI40A driver registers with the generic interface • Additional carrier drivers can be added • Individual IP module drivers interface via generic support • cat /proc/industryPack • Reports all industry pack modules • PCI40A driver registers with the generic interface • IP module drivers call the generic interface

  10. Some Details aboutGPIB support • SBS (GreenSpring) IP-488 Industry Pack module. • Linux kernel driver • Interfaces to generic IP carrier • gpibLinux.h describes user level interface (Linux ioctl calls) • requestRead, requestWrite, requestWriteRead, requestCmd • Each is single kernel call. • EPICS code • Implements Benjamin Franksen’s interface • Usable by for any GPIB device support that uses Benjamin's code • For Test the DG535 support code was ported to 3.14 • Easy port • Works for awhile on Linux before crashing!!!

  11. Some Details aboutSerial Support • Linux kernel driver • serialLinux.h describes user interface. • Uses Linux ioctl calls. • requestRead, requestWrite, requestWriteRead • requestConfig: baud rate, stop bits, etc. • requestSniff: report all I/O for requested amount of time • requestSetInputHandler: • Defines Input Handler interface • Interrupt code calls registered handler for each input character • Standard input Handler provided • Easy to add additional handlers. • Some testing but not complete. Not yet interfaced to MPF. • Will also support the Linux tty interface.

  12. Still to do • IP330 (ADC): Nothing implemented now. • Existing IP330 allows floating point in interrupt handler • Not allowed in Linux Kernel • DAC128V (DAC): Nothing implemented now • ipUnidig (Digital I/O): Nothing implemented now • OMS Motor support • Have sent/received commands from OMS PCI Motor driver • Joe Sullivan from Tim Mooney's group is working on support

  13. Immediate Plans • Make the GPIB and serial drivers more reliable • GPIB • Find and fix bugs • Serial • Implement Linux tty interface • Find and fix bugs • Document IP carrier, gpib, and serial drivers • Create alpha release under the EPICS open source license

  14. After Alpha Release • Interface serial support to MPF • Implement support for digital, and analog i/o • Linux Drivers • Interface to MPF, i.e. to EPICS • Work with Tim’s group to support synApps on Linux • Look for APS/ASD applications. • Many many records use IP serial support. • Many use IP330 support. • Monitoring only and not time critical • Work on real time performance • IOC: Spawn a real time process and use multipriority posix threads • When available use 2.6 Linux Kernel

  15. Possible Future Tasks • Allow user level to access IP register space? • Is this a good way to go? • Is this better than kernel drivers? • What about interrupts? • Successor to IP? • PMC? • PC*MIP looks dead • PCI based Transient Recorder? • ???

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