C6678 can not be enumerated by PC host.

jiajia

Hi!

The 6678 is configured as a PCIe Endpoint on our custom card. But The C6678 can not be enumerated by PC host. But after restarting the computer, the 6678 can be enumerated by the PC.

What could be the cause? I don't know how to solve this problem. Hope someone helps.

Thank you in advance!

Best Regards

over 10 years ago

0 Raja over 10 years ago

TI__Guru* 81335 points

Welcome to the TI E2E forum. I hope you will find many good answers here and in the TI.com documents and in the TI Wiki Pages (for processor issues). Be sure to search those for helpful information and to browse for the questions others may have asked on similar topics (e2e.ti.com).

This could be due to power sequening issue. Please refer the PCIe FAQ for more information from below link.

http://processors.wiki.ti.com/index.php/PCI_Express_(PCIe)_Resource_Wiki_for_Keystone_Devices

Thank you.

0 jiajia over 10 years ago in reply to Raja

Prodigy 50 points

Hi Rajasekaran,

Thanks for your reply!

I think it is the power sequencing issue. How to solve the power sequencing issue, Changing another PC or altering some parameters of the BIOS?

Also, I check the value of some registers. The value of LTSSM_STATE is 0x02 and the LTSSM_EN is 0x01. It indicates that the link between RC and EP is disconnect.Besides, The value of LOSDTCT0 and LOSDTCT1 are both 0x01. That shows loss of signal is detected both on Lane0 and Lane1.

I will appreciate it if you will give me some suggestions as soon as possible.

Regards

0 Ganapathi Dhandapani95 over 10 years ago in reply to jiajia

TI__Mastermind 28085 points

Hi JiaJia,

LTSSM_STATE field (bits[4:0]) in DEBUG0 register (0x21801728) is not 0x11 means the link is disconnected.

Have you using IBL on your custom board PCIe boot?

Please take a look at below threads

http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/p/237375/851186.aspx

http://e2e.ti.com/support/dsp/c6000_multi-core_dsps/f/639/p/363650/1282286.aspx#1282286

Thanks,

0 jiajia over 10 years ago in reply to Ganapathi Dhandapani95

Prodigy 50 points

Hi Ganapathi,

Yes, I use IBL on the custom board PCIe boot. Do you have any idea about the 'enumeration failure' problem?

Thanks,

Regards,

-Jiajia

0 Ganapathi Dhandapani95 over 10 years ago in reply to jiajia

TI__Mastermind 28085 points

Hi Jiajia,

Please try to re-enable LTSSM_EN once again in IBL code "mcsdk_2_01_02_06\tools\boot_loader\ibl\src\device\c66x\c66xinit.C, search for iblPCIeWorkaround()"

    DEVICE_REG32_W ((PCIE_BASE_ADDR + PCIE_APP_CMD_STATUS), 0x0000007);    /* enable LTSSM, IN, OB */
    while((DEVICE_REG32_R(PCIE_BASE_ADDR + PCIE_DEBUG0) & 0x11)!=0x11);    /* Wait for training to complete */

After here, wait for some time, maybe hundreds of ms. Check the LTSSM in DEBUG0 register again for bits 0-4, if it is not 0x11, then re-enable the link training by writing 1 to LTSSM_EN, this should work. Modifying the IBL code means you need to rebuild it.

Thanks,

0 jiajia over 10 years ago in reply to Ganapathi Dhandapani95

Prodigy 50 points

Hi Ganapathi,

I modify the IBL code according to your suggestion and rebuild it. But, the PC still can not enumerate the 6678. Could you provide some suggestions?

I am looking forward to your reply.

Thanks,

Regards

Jiajia

0 Ganapathi Dhandapani95 over 10 years ago in reply to jiajia

TI__Mastermind 28085 points

Hi Jiajia,

Please refer PCIe FAQ link and share your custom board power sequencing steps. Also share your modified IBL source code(c66xinit.c file).

Thanks,

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C6678 can not be enumerated by PC host.