Using PCIE switch with IMX8MP in windows 10 IoT

[Ben10]

Hi, is it possible to use PCI switch with NXP IMX8MP in windows 10 IoT to expand the PCIE slots??

[Dhruvit]

Hi @Ben10,

I hope you are doing well.

It was only positively tested on some Asus boards with i.MX8MQ, because it is not on our EVKs. With MP it was not tested but it could work.
In MX8M_PLUS_EVK.dsc it is needed to set  PcdPcie1SwitchSupport to TRUE.

This is information from R&D.

I hope this answers your query.

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit 

Thanks for the reply. I want to know if we can use PI7C9X2G304EV as the PCIE switch to expand the PCIE slot??

[Dhruvit]

Hi @Ben10,

I hope you are doing well.

Yes, it's possible. We have no experience with the PI7C9X2G304EV switch, but PI7C9X2G404SVA switch works for us.

To enable the PCIe switch, use the parameter "giMX8TokenSpaceGuid.PcdPcie1SwitchSupport|TRUE" from the file: BSP\mu_platform_nxp\NXP\MX8M_EVK\MX8M_EVK.dsc

For other settings, use the files:

• BSP\mu_platform_nxp\NXP\MX8M_EVK\AcpiTables\Dsdt-PCIe.asl
• BSP\mu_platform_nxp\Silicon\ARM\NXP\iMX8Pkg\AcpiTables\Mcfg.aslc

or document PCI Firmware Specification Revision x.x

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit 

Thanks for the reply

Can you please tell me in which board PI7C9X2G404SVA  PCIE switch was used??

[Dhruvit]

Hi @Ben10,

PI7C9X2G404SVA  PCIE switch was used with the customer board using i.MX8M Quad Processor.

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit 

Thanks for the reply.

Other than the changes that you have mentioned above, is there anything else that we need to do related to pcie switch?? Because now the PCIe switch can be seen in the device manager, but even after that when I connect a PCI card (AW-CM276MA-PUR) in the PCIe slot, it is not detected.

[Dhruvit]

Hi @Ben10,

I hope you are doing well.

Please make sure that you have checked the correctness of the power-down signal (pin 56) on the WiFi module. It could be holding the module in the off state.

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit 

Thanks for the reply

I have checked the pin that you have mentioned and it is not holding the WiFi module in the power off state. 

[Dhruvit]

Hi @Ben10,

With the information we have available about the device, we are probably not able to advise better. Would it be possible to share a schematic of the board?

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit 

Unfortunately I won't be able to provide you with the schematics. But if you want I can tell how the PCIE phy pins are connected with the PCIE M.2 slot.

[Dhruvit]

Hi @Ben10,

Please provide the information about the connection that you can share.

Thanks & Regards,
Dhruvit Vasavada

[Ben10]

Hi @Dhruvit

Thanks for the reply

We enabled UEFI log and PCIe driver log and got the following log while booting "ASSERT [iMX8PciExpress] /home/win10-iot-bsp/mu_platform_nxp/Silicon/ARM/NXP/iMX8Pkg/Drivers/PciExpress/iMX8PciExpress.c(1375): BridgeMemoryBase != ResourceAddress" and the board didn't boot." So, what does this mean?

But the board boots successfully when the UEFI debug is disabled in the firmware.