TMDS243EVM: - PCIe

Isee

Expert 6760 points

Part Number: TMDS243EVM
Other Parts Discussed in Thread: AM2434

The EVM board 3.3V can be supplied from the PCIE slot. This is probable not intended when operating EP mode (but required when operating in RC mode). Maybe a jumper to break the PCIE 3.3V supply would be a good idea for the new revision of the EVM. (We’ve just modified our RPi4 CM4 IO board so that it does not supply the 3.3V to the PCIe slot.)
I did not see any SDK functions to set the PCI Vendor ID and Product ID. Knowing the Vendor ID and Product ID is essential for the driver matching on the HOST (RC) site.
We would like to get a working PCIE EP example, where the EVM board (in EP mode) will be listed to the connected devices using the lspci command on Linux. We also need some example to transfer data directly to and from to the host memory (like DMA). (Without such kind of PCIE EP DMA the host must continuously poll the BAR “registers” which are very slow.)

Little bit more background from the call:

- Rasperry PI 4 PCIe slot – configured as route complex
- How to connect to TMDS243EVM – configured as node

over 2 years ago

0 Anita Pratti over 2 years ago

TI__Intellectual 2695 points

Hello,

TMDS243EVM is default in RC mode. On Question 1 and how to connect TMDS243EVM for EP mode, please refer to the documentation in the page under HW setup details 3.2.2.9. PCIe End Point — Processor SDK AM64X Documentation There is jumpers on this page that show the selection between EP and RC mode. This HW setup applies to TMDS243EVM also.

There is also additional MCU SDK example details under

AM243x MCU+ SDK: PCIE (ti.com) and https://software-dl.ti.com/mcu-plus-sdk/esd/AM243X/latest/exports/docs/api_guide_am243x/EXAMPLES_DRIVERS_PCIE_BENCHMARK_EP.html

Thanks,

Anita

0 Anita Pratti over 2 years ago in reply to Anita Pratti

TI__Intellectual 2695 points

Hello,

Please confirm if this answered your questions 1,3 ? I can follow-up on #2.

Thanks,

Anita

0 Isee over 2 years ago in reply to Anita Pratti

TI__Expert 6760 points

hi Anita,

They expect from a PCIe EP example, that at least the device will be detected from Linux.

This works for every PCIe FPGA development board. (I’ve tested three different FPGA PCIe cards).

This is not the case for the AM243x.

The examples does not give any hint how I can fix this.

It is also not clear, if the AM243x support PCIe Bus Mastering.

(This means from AM243x I must be able to read and write the RC (host) memory, at any time.)

What I’ve seen in the PCIe examples, that they rather work in simple peripheral mode.

If the AM243x supports bus mastering, then we would like to see some example code for that

Can that be provided?

Regards

Andreas

0 Anita Pratti over 2 years ago in reply to Isee

TI__Intellectual 2695 points

Hi Andreas,

I reached out to our internal teams and unfortunately, we currently do not have these PCIe examples or a timeline to provide the same.

I will check further if bus mastering is supported on AM243x.

Thanks,

Anita

0 Dominic Rath over 2 years ago in reply to Anita Pratti

Mastermind 7540 points

Hi,

the pcie_buf_transfer_ep sample shows bus mastering. The EP waits for the RC to write some pattern in the EP's BAR memory (dst_buf) and then writes the data back to the RC's memory.

Regards,

Dominic

0 Isee over 2 years ago in reply to Dominic Rath

TI__Expert 6760 points

Is it possible to read from the host (RC) memory in EP mode reading the Outbound Address Translation ranges?

(The efficient PCIe peripherals uses mostly the host memory, so the host won’t be blocked)

In order to continue the AM2434 PCIe evaluation we need some EP example, which will be detected as a PCIe device from some Linux host (as development platform, the RPi CM4 IO board will be used) -> can that be provided?

0 Dominic Rath over 2 years ago in reply to Isee

Mastermind 7540 points

Isee said:
Is it possible to read from the host (RC) memory in EP mode reading the Outbound Address Translation ranges?

Yes - the outbound window is used for both reading and writing host memory.

Isee said:
In order to continue the AM2434 PCIe evaluation we need some EP example, which will be detected as a PCIe device from some Linux host (as development platform, the RPi CM4 IO board will be used) -> can that be provided?

Please note that I'm not TI, so I can't comment on availability of examples. Hardware-wise the AM64x can be used as an EP connected to e.g. an x86 running Linux as a host. Never tried a RPi CM4, but it should of course be possible to make that work, too.

Regards,

Dominic

0 Ralph Jacobi over 2 years ago in reply to Isee

TI__Guru*** 135355 points

Hello Andreas,

Apologies for the lack of communication in the past month, but the requested support has remained an open topic with the team and continues to be discussed and scoped. We are expecting to have further clarity on the level of support and the timeline for such next week.

You can see a similar update in the following conversation and can follow this adjacent request to yours as well: https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1254178/am2432-not-supported-bus-enumeration/4807705#4807705

Best Regards,

Ralph Jacobi

Arm-based microcontrollers

Arm-based microcontrollers forum

TMDS243EVM: - PCIe