i.MX ProcessorsのトピックRe: PCIe pins direction

PCIe pins direction

tarterkit_ru — Tue, 05 Nov 2013 13:27:01 GMT

Hello, i want connect to i.MX6S PCIe LAN chip RTL8111E.

In RTL8111E PCIe pins is named as: HSI (input) and HSO (output) signal pair.

But i.MX6 datasheet not have information about PCIE_RX it is output or input pair.

Re: PCIe pins direction

richard_zhu — Fri, 06 Dec 2013 02:05:23 GMT

Hi:
PCIE_TX is output, and PCIE_RX is input.

Best Regard

Richard.

Re: PCIe pins direction

andyj25 — Mon, 10 Mar 2014 06:47:28 GMT

Hi Hongxing Zhu,

I have a question.

If the RTL8111E can be detected on the i.MX PCIe bus, should I be able to see it on: /sys/bus/pci_express/devices ?

Currently I see nothing there. Does that mean there's something wrong with my hardware?

Re: PCIe pins direction

richard_zhu — Mon, 10 Mar 2014 07:25:39 GMT

At least, you can see something by lspci command in Linux consol, if your ep device had been detected by pcie rc.

Richard.

Re: PCIe pins direction

andyj25 — Mon, 10 Mar 2014 07:30:41 GMT

Hi Richard,

lspci returns nothing.

Here is my schematic segment for the RTL8111E. Can you spot anything wrong with it? Thanks!!!

http://i.imgur.com/D4dFP3g.jpg

Re: PCIe pins direction

richard_zhu — Tue, 11 Mar 2014 02:35:34 GMT

Hi:

Welcome.

HW is out of my knowledge scope, you can make a reference to the pcie schematic of imx6 sabresd board of fsl.

I found there are some differences on the pull-down of the pcie clk signals between your schematic and fsl's reference schematic.

Hope it is helpful.

BTW, I'm curious about your "detected” at your side, did the pcie link have been setup between pcie rc and ep,

and the pcie rc allocate the pcie memory space and so on to pcie ep?

Richard

Re: PCIe pins direction

andyj25 — Tue, 11 Mar 2014 03:11:52 GMT

Hi Richard,

I'm loking at SPF-27516_C3.pdf. There's no RTL8111E on that, but there is PCIe.

Are you referring to the 49.9Ω resistors pulling down CLK1_N and CLK1_P on the sabresd reference schematic?

Andrew

Re: PCIe pins direction

richard_zhu — Tue, 11 Mar 2014 04:52:55 GMT

Yes, it is.

Re: PCIe pins direction

andyj25 — Tue, 11 Mar 2014 07:06:45 GMT

Thanks Richard,

I will patch those resistors and report back here if it works.

In that schematic segment I posted there is also LAN_CLKREQ. I have muxed it as a GPIO, but it is not implemented anywhere in my board-mx6q_sabresd.c.

Is this pin critical for the operation of the PCIe bus?

Here's a segment from the datasheet: http://i.imgur.com/lAfSahM.png

Re: PCIe pins direction

richard_zhu — Tue, 11 Mar 2014 07:40:44 GMT

I think it is not critical for pcie if it is not used at all.

Re: PCIe pins direction

andyj25 — Wed, 12 Mar 2014 08:45:14 GMT

The added resistors didn't help. Thanks for your tips though. We will continue debugging it.