Messages in this thread | | | From | "Horvath Gyorgy" <> | Date | Thu, 25 Sep 2003 16:57:23 +0200 | Subject | SGA155D DMA Burst length question - Memory to S5933 |
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Hi all,
I am on the way developing the driver for SGA155D. The core driver is OK. I simply copy the firmware.bin file to /dev/sga155d0, and after the firmware identification - a proper satellite driver is loaded - actually the POS (Packet Over SONET). I can then ifconfig my pos0 - and here weeee goooo.
Now I can DMA well from the card to the PC memory - even for long-bursts. The data is OK. I see on the oscilloscope a short transfer at the beginning (8 DWORDS or so) - a little gap, and the rest go smoothly in one long piece.
I tried then to DMA from the PC memory to the card. What I see is: 9 DWORDS, some 9+more gap, 9 DWORDS, some 9 more gap, etc... I'd like to see a smooooooooooth transfer - not that 50%.
I have S5933 on-board, and I find some issues elsewhere about advanced PCI commands when spanning across cache-lines, but I am not sure that is the issue... (MR/MRL/MRM) Can S5933 do them?
Any tips/suggestions?
Also, what is the suggested burst size under Linux for such a NET device like mine? (cca. 2x 140 Mbps, MTU is 4470)
Thanks for in advance: Gyuri
Gyorgy Horvath, Technical University of Budapest -------------- Dept. of Telecom. and Telematics
Tel.: +36-1-463-1865, Fax.: +36-1-463-1865 Mail: horvaath@bme-tel.ttt.bme.hu FTP: ttt-pub.ttt.bme.hu ./income - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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