am5728: PCIe link fails

matusan

Guru 10235 points

Part Number: AM5728

Hello, TI Experts,

Our customer sent us some questions about PCI Express.

They found PCIe GEN1-GEN2 switching Link fail at boot on their custom board.

- Is there any clue to solve this problem?

- Is there any information or document of LTSSM State?

- Is there any register information of PCIE State Machine or Error status?

We would appreciate if you tell us the recommended way to analyze the PCIe Link fail phenomena.

Best regards,

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

What software are you using?

0 matusan over 8 years ago in reply to Biser Gatchev-XID

Guru 10235 points

Hi,

Thank you for your prompt reply.
We will ask to the customer.

Best regards,

0 matusan over 8 years ago in reply to matusan

Guru 10235 points

Hi,

We got the answer from the customer.
They use "3rd-party OS".

And they also see sample code as below.
- pdk_am57xx_1_0_6\packages\ti\drv\pcie\example\sample\src\pcie_sample.c

They understand the difficulty of getting advice from TI with no TI-SDK.
(So they refer sample code of TI-SDK. )

Under this situation,
We would appreciate if you tell us possible information and suggestion as follows to analyze AM5728 PCIe behavior on their system.
- Information or document of LTSSM State?
- Register information of PCIE State Machine or Error status?

Best regards,

0 -DK- over 8 years ago

TI__Mastermind 27890 points

There's not a lot of information to work with here. Can I assume that the link works well at PCIe Gen1 speeds and only fails when attempting to transition to PCIe Gen2 speeds?

The more details you can provide the better. :)

0 lding over 8 years ago in reply to -DK-

TI__Guru* 95265 points

Hi,

Does GEN1 work? LTSSM state machine is in the PCI-SIG specification. They are also summarzied in TI AM5728 TRM, PCIECTRL_TI_CONF_DEVICE_CMD register. You can decode bit 7:2 for information. Is AM5728 the PCIE EP or RC? If you used 3-rd party software but with TI RTOS PCIE driver inside, the GEN2 support is enabled by default.

Regards, Eric

0 matusan over 8 years ago in reply to lding

Guru 10235 points

Hi,

Thank you for your kindness.
This information is very helpful!

Best regards,

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am5728: PCIe link fails