Re: [BUG] rk3399-rockpro64 pcie synchronous external abort

[Bjorn Helgaas <helgaas@kernel.org>]

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