On Sun, Nov 10, 2019 at 10:43:48AM -0500, Peter Geis wrote: > I plugged in an i350 two port nic and examined the assigned address spaces. > I've attached it below. > Judging by the usage, I think this controller has enough address space > for another two port NIC, and that's about it. > I'm pretty sure now that the rk3399 controller just doesn't have the > address space to map larger devices. > I'm pretty sure the IOMMU would allow us to address system memory as > pcie address space and overcome this limitation, but I don't know how > to do that. I don't think you're out of MMIO space, at least in this instance. It looks like you have 32MB available and the two-port NIC on bus 01 only takes 5MB. The IOMMU is used for DMA (e.g., reads/writes initiated by the NIC), while the MMIO space is used for CPU programmed I/O (reads/writes done by the driver running on the CPU). > The address space for the nic is below: > f8000000-f8ffffff : axi-base > fa000000-fbdfffff : MEM 32MB. > fa000000-fa4fffff : PCI Bus 0000:01 5MB. > fa000000-fa07ffff : 0000:01:00.0 > fa000000-fa07ffff : igb > fa080000-fa0fffff : 0000:01:00.0 > fa100000-fa17ffff : 0000:01:00.1 > fa100000-fa17ffff : igb > fa180000-fa1fffff : 0000:01:00.1 > fa200000-fa27ffff : 0000:01:00.0 > fa280000-fa2fffff : 0000:01:00.0 > fa300000-fa37ffff : 0000:01:00.1 > fa380000-fa3fffff : 0000:01:00.1 > fa400000-fa403fff : 0000:01:00.0 > fa400000-fa403fff : igb > fa404000-fa407fff : 0000:01:00.1 > fa404000-fa407fff : igb > fd000000-fdffffff : f8000000.pcie
