Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Thu, 6 Sep 2012 22:54:50 +0200

Am Donnerstag, 6. September 2012, 21:57:00 schrieb Mark Rivers:
> I would like to renew my plea for an update to the EPICS devLib to support
> VME operations in an OS-independent manner.  This includes not just the
> DMA operations that this thread originally referenced, but also basic
> register write and read operations.
>
> For example, when Kate Feng converted my SIS320 driver from vxWorks to
> RTEMS she made changes like the following:
>
> -        status = sysDmaFromVme(dmaId_, fifoBuffer_, (int)fifo_base_,
> VME_AM_EXT_SUP_D64BLT, (count)*sizeof(int), 8); +#ifdef __rtems__
> +        status= BSP_VMEDmaStart(dmaId_,fifoBuffer_PCIaddr,
> fifo_baseVMEaddr_, (count)*sizeof(int)); +#else
> +        status = sysDmaFromVme(dmaId_, fifoBuffer_, fifo_baseVMEaddr_,
> VME_AM_EXT_SUP_D64BLT, (count)*sizeof(int), 8); +#endif
>
> According to Till's message this might not have been necessary, since he
> said he had an RTEMS implementation of Andrew's API, so perhaps the same
> API call could have been used?
>
> But there were also changes like this:
> -    registers_->irq_control_status_reg = SIS3820_IRQ_SOURCE4_DISABLE;
> +    writeReg32(&registers_->irq_control_status_reg,
> SIS3820_IRQ_SOURCE4_DISABLE);
>
> and this:
> -  firmwareVersion_ = registers_->moduleID_reg & 0x0000FFFF;
> +  firmwareVersion_ = readReg32( &registers_->moduleID_reg) & 0x0000FFFF;
>
> So where I was doing register access directly, on RTEMs this is being
> wrapped in a function or macro.  I understand that this may be needed on
> some architectures to ensure that writes are done immediately, etc.  The
> problem is that Kate's code won't build on vxWorks because the readReg32
> function is defined in a header file only included for RTEMS.  I don't
> know of a vxWorks equivalent.
>
> We really need something standard in EPICS base that we can all use in our
> VME drivers to make them OS and architecture independent.

I agree, wholeheartedly. The more so since the RTEMS way to access registers
strikes me as the better idea anyway: matching a C struct definition with the
register layout (as it is done traditionally in EPICS drivers) is error prone
and non-portable, since the exact memory layout of a struct depends on
architecture and compiler. So, yes, we need a set of access functions (or
macros) like read/writeReg8/16/32 packages as an OSI library; and indeed
devLib is the right place to put them.

--
Ben Franksen
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> From: [email protected] [[email protected]] on
> behalf of Till Straumann [[email protected]] Sent: Wednesday,
> February 15, 2012 9:21 AM
> To: [email protected]
> Subject: Re: Epics driver using BLT or CBLT to read FIFO wanted
>
> FWIW. We also have a RTEMS implementation of Andrew's DMA API.
> And yes, I'd think integrating this into devLib would be desirable.
>
> Till
>
> On 02/15/2012 08:24 AM, Mark Rivers wrote:
> > Hi,
> >
> > My SIS3820 driver reads out a FIFO using BLT. Here is the code snippet:
> >       if (useDma_ && (count >= MIN_DMA_TRANSFERS)) {
> >
> >         asynPrint(pasynUserSelf, ASYN_TRACE_FLOW,
> >
> >                   "%s:%s: doing DMA transfer, fifoBuffer=%p,
> >                   fifo_base=%p, count=%d\n", driverName, functionName,
> >                   fifoBuffer_, fifo_base_, count);
> >
> >         status = sysDmaFromVme(dmaId_, fifoBuffer_, (int)fifo_base_,
> >         VME_AM_EXT_SUP_D64BLT, (count)*sizeof(int), 8); if (status) {
> >
> >           asynPrint(pasynUserSelf, ASYN_TRACE_ERROR,
> >
> >                     "%s:%s: doing DMA transfer, error calling
> >                     sysDmaFromVme, status=%d, buff=%p, fifo_base=%p,
> >                     count=%d\n", driverName, functionName, status,
> >                     fifoBuffer_, fifo_base_, count);
> >
> >         }
> >
> > You can get the complete file containing this snippet here:
> >
> > https://subversion.xor.aps.anl.gov/synApps/mca/trunk/mcaApp/SISSrc/drvSIS
> > 3820.cpp
> >
> > This code uses the DMA functions that Andrew Johnson provides in the
> > vxWorks BSPs at the APS.
> >
> > I would like to suggest (again) that these functions or something similar
> > should be added to devLib in EPICS base, so that we can all write
> > portable code that uses DMA!
> >
> > Cheers,
> > Mark
> > ________________________________________
> > From: [email protected] [[email protected]] on
> > behalf of Bai Jiaoni [[email protected]] Sent: Wednesday, February 15,
> > 2012 7:17 AM
> > To: [email protected]
> > Subject: Epics driver using BLT or CBLT to read FIFO wanted
> >
> > I want to wirte a driver for the hardware, which needs to use record to
> > read the data of FIFO(altera FPGA) by BLT or CBLT. Do you know some
> > other dirvers finishing the same function?
> > Version：Epics 3.13 or 3.14; vxWorks 5.4; VME bus
> >
> > I am looking forward to your reply.

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System