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EPICS

Linux EPICS IOC SupportIndustry Pack and Stepper Motor

Status ReportEPICS Meeting at IHEP

August 2002

Marty Kraimer

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EPICS

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.

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EPICS 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

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EPICS 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.

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EPICS 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.

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EPICS

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

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EPICS 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

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EPICS

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)

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EPICS

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

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EPICSSome Details about

GPIB 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!!!

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EPICSSome Details about

Serial 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.

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EPICS 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

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EPICS

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

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EPICS

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

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EPICS 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? ???