Re: [PATCH v2 1/2] PCI: dwc: Allow drivers to skip MEM outbound iATU setup

[Xincheng Zhang]

Hi Niklas,

On Wed, Oct 14, 2026 at 10:27:57AM +0200, Niklas Cassel wrote:
> Sorry for commenting on this patch after it was accepted.
>
> But... since this behavior is intrinsic to the DWC controller, rather than
> being SoC specific... Why bother creating a flag for it?
>
> Is there a reason why this can't just be a simple:
>
> if (atu.parent_bus_addr == atu.pci_addr)
> 	continue;

Thanks for pointing this out.

I added the flag because I had only tested no-match pass-through on DP1000.
But you are right that this is DWC behavior, not SoC-specific, and comparing
the two addresses is enough to tell whether translation is needed.

Since the series has already been applied, I will send a follow-up patch
that skips MEM outbound iATU programming when atu.parent_bus_addr is equal
to atu.pci_addr, and removes bypass_ob_mem_iatu and the UltraRISC-specific
setting. CFG and I/O accesses, as well as non-identity-mapped MEM ranges,
will continue to use outbound iATU windows.

Thanks,
Xincheng