DMA configured as AXI Bridge MSI-X Interrupt Implementation

[sdcarlson]

Hello!

I am trying to generate an MSI-X interrupt that will go through the AXI Bridge out over PCIe.  

My device generates interrupt ---> AXI Bridge ---> PCIe

Steps taken:

1. In reviewing PG195 (DMA/Bridge Subsystem for PCI Express v4.0) page 5 says refer to PG194 if configured as a PCIe Bridge
   • "AXI Bridge" is the mode selected so I refer to PG194.
2. In PG194 (AXI Bridge for PCI Express Gen3 Subsystem v3.0) page 65 the "Interrupts" section says refer to PG156.
3. In PG156 (UltraScale Devices Gen3 Integrated Block for PCI Express v4.4) on page 194 it describes
   • "MSI-X Interrupts need to be generated by the user application and presented on the transmit AXI4-Stream interface."

Knowing this how do I get an interrupt from my block to the AXI Bridge? The AXI Bridge is not configurable as an AXI4-Stream Slave device.

I figure there are two options:

1. I have to use a converter to go from AXI4-Stream to AXI4.  If so, why not just send the interrupt out over AXI4 from my block?
2. I'm misunderstanding the product guides and you can send the MSI-X interrupt as an out band message despite being an AXI Bridge.

Can anyone help me out?

Many thanks,

SD

[venkata]

Do you get usr_irq_req and usr_irq_ack ports at the IP interface? You will need to use these ports to assert the interrupt.

You can check the details of interrupt handling on page 13 of PG195.

We will have the interrupt section reviewed properly for the next documentation release.

[sdcarlson]

Hello venkata,

I do have the usr_irq_req and usr_irq_ack ports at the IP interface even in AXI Bridge mode. 

I'll try using them as PG195 specifies, rather than how PG194/PG156 specify.

Thanks for the reply!  I'll post again when I've gathered my results.

[stew.hansen]

Were you able to find a solution to this?

We are working on something similar.