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Network Driver and instruction cache.
- Date: Thu, 29 Nov 2001 19:52:14 -0600
- From: joel at OARcorp.com (Joel Sherrill)
- Subject: Network Driver and instruction cache.
Brett Swimley wrote:
> Hi all -
Well if no one else will reply...
> I'm porting the Motorola MCF5272 Coldfire to RTEMS and have run into an
> issue with the network driver while enabling the instruction cache on the
This type of issue is normally restricted to data caches.
Is this a network driver for the on-CPU NIC?
Does the MCF5272 have some data caching tied to enabling the instruction
> I'm running the latest snapshot of RTEMS 4.5.0.
I suspect you could be running any version and see the same behavior. :)
> When the instruction cache is disabled, and I try pinging my board, I get no
> errors and no packet loss. The network driver appears to work flawlessly.
> I have tried several options for enabling my instruction cache. Each option
> gives me less than perfect response from the network driver (either no
> response or lost packets) - but the rest of my application seems to be
> running perfectly.
> Should I expect occasional packet losses from ping?
Heavy flood pinging can result in lost packets. Simple pinging on a
dedicated network should almost never result in one.
> If not, would anyone
> have any suppositions why enabling the instruction cache would impede the
> network driver/network stack?
My guess is that enabling the instruction cache makes all of the code
run faster thus exposing some window in your network driver. It is
that there is a window somewhere else if there are other devices
> I have tried disabling the cache on my memory mapped internal peripherals,
> which includes the on board Fast Ethenet controller.
This sounds like a data caching issue which doesn't sound like a
> Any suggestions would be appreciated.
I can bet you you would. This could be hard to debug.
> Brett Swimley
> Sr. Design Engineer
> Advanced Electronic Designs, Inc.
> brett.swimley at aedinc.net
> ph: 406-585-8892
> fax: 406-585-8893
Joel Sherrill, Ph.D. Director of Research & Development
joel at OARcorp.com On-Line Applications Research
Ask me about RTEMS: a free RTOS Huntsville AL 35805
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