Re: Shopping for low-power ARM firewall SBC

[Robert Swindells <rjs%fdy2.demon.co.uk@localhost>]

Martin Guy wrote:
>On 9/15/09, Anders Lindgren <ali%df.lth.se@localhost> wrote:
>>   I am looking for a low-power, preferrably-pc104-form-factor (or
>> thereabouts) dual ethernet SBC type of ARM board with a CF slot for building
>> a custom NetBSD firewall thingy.
>>
>>   I've also been looking at
>> http://www.embeddedarm.com/products/board-detail.php?product=TS-7300
>> which really has more features than I need, but a more attractive price.
>
>The 7300 is based on the Cirrus EP93xx chip, which is a Soc providing
>only one ethernet port, and it can't read or write more than 3 Mbytes
>per second to it 100Mbps link. The ethernet hardware in the SoC is a
>bit simple so you have to checksum all data with the main CPU, which
>bottoms out at 100% system time at 3mbytes per second.
>I dunno where they're deriving the second ethernet port from - maybe
>it's on the the FPGA? - so if you're lucky the second ethernet will be
>processor-efficient but you're still stuck with 3Mbytes/sec
>throughput, if that matters.

The second ethernet port uses the OpenCores controller which can do
checksums in hardware. I have no idea how much difference this makes
to transfer rates.

<http://www.opencores.org/project,ts7300_opencore>

I'm not sure that there is a NetBSD driver for this ethernet controller
yet though.