PCIe switch on Jetson TX2 carrier card

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hello,
We have designed a carrier card around Jetson TX2i. We are using a PCIe Switch (PEX8714 from Broadcom) which takes PCIex4 (PCIe Interface #0 x4 in TX2i) root port from jetson module and switches to four PCIex1 root ports which eventually gets connected to four mini PCIe slots. I need some help to enable the PCIe switch in L4T, so that all the mini PCIe devices can be integrated.
Any help will be appreciated.

Thanks
Goutam

2

Hello,
Is there anyone who can help with the above query ?

Thanks

3

Hi goutam.gupta,

What is your current problem? Are you able to see the devices in lspci -vvv?

4

I am not able to see the device in lspci. What changes do i need to make to enable the PCIe switch ? Thanks for your help.

5
  1. Is other pcie device able to be detected on your custom carrier board?
  2. Are you able to put this pcie switch to nvidia devkit and see if devkit is able to detect it?

Also, better always sharing the dmesg.

6

Hello WayneWWW,

  1. All the PCIe devices are routed through the PCIe switch. Hence, None of the mPCIe device are being detected.

  2. We can not connect the PCIe switch on the dev kit as it is a BGA package and these high speed lines can not be routed.

7

Hi goutam.gupta,

We should verify if pcie function is working on your custom carrier board first. Thus, any kind of pcie deivce should be fine. Don’t need to use pcie switch at this moment.

Maybe you could find a pcie network card, put it on your board and see if it is shown in lspci.
If even such simple case fails, then we don’t need to check pcie switch at this moment.

8

Hi WayneWWW,

We have four mPCIe slot in my custom carrier board. All of these four slots are connected to PCIe-x4 root port through the PCIe switch. There is no other PCIe slot connectivity on the carrier card. How can we connect any other PCIe devcie/PCIe network card in this case? There is no provision to bypass the switch as well. Can you please suggest if we need to change some configuration setting for this switch to get recognized? Or do we need any kind of driver from the PCIe switch vendor? We are using PEX8714 device from Broadcom

Thanks again for your quick response !!

9

Then could you firstly share your boot up log with us?

10

The carrier board is non-functional now as one of the power management IC stopped working. We will share the log once the board is up.

11

Also, are you using PEX0/USB_SS1/PEX2/PEX_RFU on your design?

12

We are using PCIe lanes in default mode i.e config 2 as suggested in the OEM design. PEX0,USB_SS1, PEX2,PEX_RFU are used as 1x4 lanes to connect to the PCIe switch. We are using USB_SSO ports for USB3.

13

Then no configuration needed. Waiting for your log.