Linux/TMDXIDK5718: Cannot find PCIe EP device on host

Hi Rex,

I read that thread but it seems there's no solution provided. If I keep the clock pins on the cable, will it work? The AM57x device will get the clock signals from RC and not send clock signals to RC? If this doesn't work, I guess the only option is using two AM57x devices connecting each other, since there're hardly some PCIe settings available on a normal PC BIOS?

Thanks.

Thanks Rex for the additional information. It seems more works need to be done which I'm not familiar with, I'll use two TMDXIDK5728 boards with the modified cable for this feature. Thank you for your kind help!

Hi Rex,

I've got another TMDXIDK5728 board, and tried to connect the 2 boards with the modified cable. I built different Linux kernel images for the 2 boards, one enabled DRA7XX_HOST one enabled EP, followed the steps (http://software-dl.ti.com/processor-sdk-linux/esd/docs/latest/linux/Foundational_Components_Kernel_Drivers.html#pcie-end-point) in EP, then booted the board of rc mode. But from the host board only the PCIe controller device (0x104c:0x8888) is found, no endpoint device. What do you think may be the problem or there're more configurations to be done? Thanks!

Hi Rex,

I used the pre-built kernel as host, it cannot find the endpoint device too. The video used the old release so the kernel config is not the same as latest PSDK, and another difference is a AM57xx-EVM board is used as EP with a miniPCIe-PCIe adapter, while I used 2 TMDXIDK5728 boards.

Here're the configurations of my setup:

2 TMDXIDK5728 boards, modified PCIe X1 cable with 12V/3.3V/clk+- pins disabled;

The PSDK used is the latest 05.03.00.07, kernel 4.14.79, when rebuild the kernel the used config is tisdk_am57xx-evm_defconfig, dtb is am572x-idk.dtb;

Followed the steps on EP (http://software-dl.ti.com/processor-sdk-linux/esd/docs/latest/linux/Foundational_Components_Kernel_Drivers.html#pcie-end-point), the endpoint controller folder in configfs is there, and all settings didn't show additional errors. After echo 1 to controller start, boot the RC board;

on RC board console lspci shows only PCIe controller 0x104c:0x8888, dmesg shows this line, not certain it's expected or not: "dra7-pcie 51000000.pcie: phy link never came up".

Xin

Hi, Xin,

We run PCIe EP nightly test for each night's build. Though it is run on the other EVM, DRA7x-EVM, not the AM57x-EVM, but they are the same family SOC. AM57x is based on DRA7x. It's hard to understand why it doesn't work for you.

As development moving along, some steps needed during the video was shot are included as default in the later release, such as enabling the EP mode, and epf test through menuconfig. Some are still needed. I assume for the EP, you have rc status set to disabled, and ep status to okay in the dts file.

You won't see EP if you get phy link never came up. The handshaking with EP didn't complete.

Rex

Hi Rex,

I see you mentioned this in both threads:

"the EP should take clock from RC. So, the PCIE_SS shouldn't use current internal clock source, but take the external clock from RC through LJCB_CLKP/N by programming ACSPCIE in RX mode.

Please refer to section 26.4 PCIe PHY Subsystem of the AM5728 TRM, SPRUHZ6J, and take a look at Figure 26-17."

If the another TMDXIDK5728 plays the RC role, this is not needed as the EP using the internal clock which is same as the RC clock?

Xin