Modifying QSys PCIe reference design to have dual port OCM

Yes! I would have expected an IRQ as well. I think I read the magic number in the source code somewhere, but I don't remember which one. It was as blatent as an if statement in a loop comparing the last element of an array to a constant. Details are a bit hazy. To be quite honest, its been a long time.

In the end, I rolled my own kernel modules for DMA transfers. I kept polling at the SGDMA engine's buffer fill levels an enqueue additional transfers as necessary.

If you manage to get IRQs working with DMA on Altera's PCIe HIP, please let me know. I couldn't find any Altera literature on this at the time. I tried many different ways, but interrupts just wouldn't propagate through the PCIe HIP.