UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Visitor jssk
Visitor
322 Views
Registered: ‎03-31-2019

XDMA linux driver not showing devices?

Jump to solution

Hi,

I'm deveoping with the Xilinx's xdma linux driver. The problem I'm having is that everytime I load a new bitstream, the driver doesn't see any xdma devices in /dev.

I would have to reboot then do insmod xdma.ko then ls /dev would show the devices.

Is there any way I don't have to reboot the host after reloading bitstream?

 

Thanks for your help in advance!

0 Kudos
1 Solution

Accepted Solutions
Highlighted
Xilinx Employee
Xilinx Employee
296 Views
Registered: ‎08-07-2007

回复: XDMA linux driver not showing devices?

Jump to solution

hi @jssk 

 

please check this

 

https://www.xilinx.com/support/answers/37406.html

 

Thanks,

Boris

------------------------------------------------------------------------------
Don't forget to reply, give kudo and accept as solution
------------------------------------------------------------------------------

View solution in original post

3 Replies
Highlighted
Xilinx Employee
Xilinx Employee
297 Views
Registered: ‎08-07-2007

回复: XDMA linux driver not showing devices?

Jump to solution

hi @jssk 

 

please check this

 

https://www.xilinx.com/support/answers/37406.html

 

Thanks,

Boris

------------------------------------------------------------------------------
Don't forget to reply, give kudo and accept as solution
------------------------------------------------------------------------------

View solution in original post

Visitor jssk
Visitor
262 Views
Registered: ‎03-31-2019

回复: XDMA linux driver not showing devices?

Jump to solution

This is exactly what I needed, thank you!

0 Kudos
Visitor fpgadepixus
Visitor
228 Views
Registered: ‎01-31-2019

回复: XDMA linux driver not showing devices?

Jump to solution

Did that recommendation work? I ask because the original advice was from several years ago, and there are lots of different reports about some methods not working on some machines / linux versions etc..

The reason that you can't see the device after reconfiguring is that the PCIe core has lost connection with the PCIe root device on the motherboard.

Normally a motherboard boots, then queries all the attached devices, then configures the devices to operate at their maximum speed. This has to happen quite soon after power up, so the only way to get a PCIe FPGA working like this is to reprogram the flash memory on the board, and power cycle the whole system. That way the FPGA loads from on-board Flash, though note that this _must_ happen very quickly within the recommended PCIe power up time, so that the motherboard can detect the new device.

Obviously, it would be very useful if we could force the motherboard to do a PCIe rescan to detect a new configuration after a reprogram. There is a stack overflow thread about this here. But note that none of the methods there seem to work in all circumstances, but you might be in luck. The method suggested in the previous answer seems a bit chancy to me ..

A really useful technique would be to use partial reconfiguration. That is, that the PCIe part of your design is left intact, and just reconfigure the customised part of the design. That way, the PCIe link would not be dropped, and development would be a lot easier.

In fact, one could go further, and connect a port from the PCIe part to the internal reconfiguration interface, so that the partial reconfiguration can be performed over the PCIe bus itself.

.. and guess what, this is exactly what the Alveo acceleration cards do. Now you would think that such an IP block would be made freely available in the IP catalogue, but no such luck I'm afraid.

 

 

0 Kudos