PCIe Access - achieve bursts without DMA

David Laight David.Laight at ACULAB.COM
Fri Jan 31 01:19:12 EST 2014

>From Moese, Michael
> Hello PPC-developers,
> I'm currently trying to benchmark access speeds to our PCIe-connected IP-cores
> located inside our FPGA. On x86-based systems I was able to achieve bursts for
> both read and write access. On PPC32, using an e500v2, I had no success at all
> so far.

I'm not sure that you can.
I had to write a simple driver for the PCIe CSB bridge dma on a 83xx ppc.
I think that might be the one in the e500v2.

I don't know how fast 'normal' PCIe slaves are, but we were accessing
an Altera fpga and the latency is less than pedestrian.
I think an ISA bus can run faster!
With moderate length transfers, the throughput was more than adequate.


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