Issues when testing DMA feature provided by Avalon MM+ IP with S10 GX dev kit card on Ubuntu 18.04

[He4Forum]

I have installed s10 GX dev kit fpga card on Ubuntu 18.04 and program the Avalon MM+ Hard IP to the card. 

While I meet some issues when testing the DMA feature.

For the test application which locates at ~/avmm_bridge_512_0_example_design/software/user/example/intel_fpga_pcie_link_test, all the test mode cannot run successfully.

For example, the first test, Doing 100 writes and 100 reads, failed. I put the results of first 10 tries below.

At dword 0x0
Wrote 0x120aed54
Read  0xffffffff
At dword 0x1
Wrote 0x4db4d210
Read  0xffffffff
At dword 0x2
Wrote 0x616cd2bb
Read  0xffffffff
At dword 0x3
Wrote 0x29ad0aff
Read  0xffffffff
At dword 0x4
Wrote 0x31f54bf7
Read  0xffffffff
At dword 0x5
Wrote 0x7f08785d
Read  0xffffffff
At dword 0x6
Wrote 0x4fde1236
Read  0xffffffff
At dword 0x7
Wrote 0x401d6525
Read  0xffffffff
At dword 0x8
Wrote 0x44a0f03b
Read  0xffffffff
At dword 0x9
Wrote 0x49ebcbdc
Read  0xffffffff

For each time testing, the result of reading from the memory is 0xffffffff. While it shows reading and writing operaions don't meet errors. Only the numbers don't match.

Number of write errors:       0
Number of read errors:        0
Number of dword mismatches: 100

While I look into the code, I do not find where the device memory address is initialized for device memory. It is just initialized to NULL.

char *addr = NULL;

I am wondering why the test application does not use memory map to get a address mapping to the FPGA card memory. I'm not sure if it is initialized in other functions and whether the address(NULL) is the reason to cause the mismatches. 

However, other testing mode cannot work as well. So maybe there are caused by other reasons.

When I installed the PCIe driver for the FPGA card, as the provided driver code is for CentOS, I modified some code to make it could be successfully installed on Ubuntu. Not sure if my modifications will cause any issue.

Hope someone have ideas on the issues I've met. Thank you and look forward to reply.

[He4Forum]

When I de-select the "Enable Bursting Avalon-MM Master interface", it shows there are 2 errors of system connectivity(at the bottom of the 2nd pic), and I cannot generate the design.

[skbeh]

On 'System' tab, click 'Remove Dangling Connections'

[He4Forum]

I just notice another setting. The Avalon MM need to operate at 250MHz, right? Do I need to change the hardware frequency to 250MHz when I am programming the design to card?

[skbeh]

The screenshot you shared here is the JTAG clock frequency of the USB-Blaster II download cable. The JTAG TCK or DCLK frequency can be either 24M, 16M and 6M.

I don't think it has relationship with the PCIe IP Avalon-MM setting.

[He4Forum]

Unfortunately, the same error still occurs.

This time DMA test runs a bit longer than before. The usb is disconnected after 20,000 loops of testing.

At the same time, during the test, I found that the previous usb was connected to an usb3.0 interface of the motherboard, so I plugged it into an usb2.0. While no difference about the result.

[He4Forum]

Atfer how much time the USB will be disconnected seems very random. Maybe I just start the test, or have runned the test for a while.

[He4Forum]

I think it is very likely that the temperature is too high to make the USB disconnected. I notice in user guide documentation https://www.intel.com/content/www/us/en/docs/programmable/683674/current/thermal-limitations-and-protection.html , it mentions that the board will be powered off when the temperature crosses 100C. Then we need to replug the power supply to make it work again. It's very similar to our situation. I have added a tiny fan blowing the card directly to see whether it could work.

[skbeh]

Good to know that the USB connection issue could be potentially caused by high temperature.

Make sense that since the DMA test can perform up to 20k cycles, doesn't seems like it is design issue anymore.

[He4Forum]

Yep. And thank you very much for your support and patience.