iMX8M PCIe bus damaged

[calf]

CPU starup to print the following information on the RS232 serial port:

[    5.224015] imx6q-pcie 33800000.pcie: pcie phy pll is locked.

[    5.471573] imx6q-pcie 33800000.pcie: phy link never came up

[    5.477251] imx6q-pcie 33800000.pcie: failed to initialize host

[    5.483179] imx6q-pcie 33800000.pcie: unable to add pcie port.

[    5.492233] imx6q-pcie: probe of 33800000.pcie failed with error -110

[    5.510506] imx6q-pcie 33c00000.pcie: 33c00000.pcie supply epdev_on not found, using dummy regulator

We can find that PCIe bus can’t link up. We test all siganls about PCIe bus. PCIe_REFCLK is normal.

PCIe_TX(from CPU to device) has no signal. PCIe_RX(from device to CPU) has normal signal.

Finally we remove the CPU and populate new CPU chip to recover the board.

I want to know what casue can lead that CPU(iMX8M) is damaged.

[igorpadykov]

Hi calf

>I want to know what casue can lead that CPU(iMX8M) is damaged.

this may be due to ESD issues or chip overheating.

Best regards
igor

[calf]

Hi， igor:

May CPU overheating damage the CPU hardware? Why is PCIe_A bus damaged always?

You have ever meet similar issue in other customers?

BRs

Calf

[calf]

Hi，igor:

I also want to know what root cause lead that issue. iMX8M CPU's PCIe_1 bus has one device(BCM56160 Broadcom Switch chip). Only PCIe_1 bus is damaged.

I need some suggestion or ideas for testing.

In addition, other functions  of this iMX8M CPU are normal. The other PCIe_2 bus is OK. 

BRs.

[calf]

Hi，igor:

I have the other issue about iMX8M PCIe application.

The PCIe_1 Bus use the CPU internal PCIe clock. But device(BCM56160) use the external clock from 9FGV0441AKLFT(meet PCIe Gen1/2/3 clock chip). PCIe_1 Bus can work normally. But for a long time(several days or perhaps several weeks), software show a amount of errors on the PCIe_1 access. Maybe that finally will lead the  PCIe_1 Bus link down.

I want to know the root cause for the issue. Do this problem occur because PCIe clock of two sides isn't  the same source?

Do you know the similar issue? Share your experience.

Thanks!