IMX8MQ : PCIE : phy link never came up

[jemish_1990]

Hi All,

We are working product based on IMX8MQ (MIMX8MQ6DVAJZAA) processor.

Kernel version: 4.14.98

• We have been using this processor since long time. But with new batch of boards we have started facing one serious issue. After using board for a while we see that PCIE bus is not working.
• On board booting we are getting following error

[ 0.264196] PCI: CLS 0 bytes, default 128
[ 2.524876] ehci-pci: EHCI PCI platform driver
[ 2.541151] ohci-pci: OHCI PCI platform driver
[ 4.163690] imx6q-pcie 33800000.pcie: 33800000.pcie supply epdev_on not found, using dummy regulator
[ 4.173139] OF: PCI: host bridge /pcie@0x33800000 ranges:
[ 4.186610] OF: PCI: No bus range found for /pcie@0x33800000, using [bus 00-ff]
[ 4.186619] OF: PCI: IO 0x1ff80000..0x1ff8ffff -> 0x00000000
[ 4.186625] OF: PCI: MEM 0x18000000..0x1fefffff -> 0x18000000
[ 4.187449] imx6q-pcie 33800000.pcie: pcie phy pll is locked.
[ 4.465076] imx6q-pcie 33800000.pcie: phy link never came up
[ 4.470756] imx6q-pcie 33800000.pcie: failed to initialize host
[ 4.470759] imx6q-pcie 33800000.pcie: unable to add pcie port.
[ 4.471331] imx6q-pcie: probe of 33800000.pcie failed with error -110
[ 4.496868] imx6q-pcie 33c00000.pcie: 33c00000.pcie supply epdev_on not found, using dummy regulator
[ 4.506294] OF: PCI: host bridge /pcie@0x33c00000 ranges:
[ 4.511707] OF: PCI: No bus range found for /pcie@0x33c00000, using [bus 00-ff]
[ 4.519263] OF: PCI: IO 0x27f80000..0x27f8ffff -> 0x00000000
[ 4.529273] OF: PCI: MEM 0x20000000..0x27efffff -> 0x20000000
[ 4.540354] imx6q-pcie 33c00000.pcie: pcie phy pll is locked.
[ 4.788774] imx6q-pcie 33c00000.pcie: phy link never came up
[ 4.794455] imx6q-pcie 33c00000.pcie: failed to initialize host
[ 4.800437] imx6q-pcie 33c00000.pcie: unable to add pcie port.
[ 4.806964] imx6q-pcie: probe of 33c00000.pcie failed with error -110

• Due to this error PCIE bus is not recognizing any of the devices connected on PCIE bus.
• Once this issue occurs we are unable to recover PCIE bus.

Any suggestion or pointers to overcome this issue would be appreciated.

Thanks,

Jemish

[Sanket_Parekh]

Hi @jemish_1990 

I hope you are doing well.

-> Have you followed the standard hardware design steps of pcie in your custom board?

-> Can you please check the below mentioned points into your custom board?

1. 3V3 voltage and clock signal

2. Resistance from the transmitter to the ac-coupling capacitor. Then, measure from the other side of the ac-coupling capacitor to the receiver.

3. power and ground on both sides of the link

4. check the voltage supplies at the transmitter with respect to ground. Then probe from the ground of the transmitter to the ground of the destination of the signal and see if there is any voltage difference.

Thanks & Regards.

Sanket Parekh

[jemish_1990]

Hi,

This issue resolved with following change.