Re: [PATCH v7 3/6] PCI: dwc: Allow glue drivers to return mutable EPC features

From: Niklas Cassel <cassel@kernel.org>
To: Frank Li <Frank.li@nxp.com>
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Subject: Re: [PATCH v7 3/6] PCI: dwc: Allow glue drivers to return mutable EPC features
Date: Wed, 14 Jan 2026 21:13:34 +0100	[thread overview]
Message-ID: <aWf47s1oY-bjCDSA@fedora> (raw)
In-Reply-To: <aWfyDHZCoh1t6/vP@lizhi-Precision-Tower-5810>

On Wed, Jan 14, 2026 at 02:44:12PM -0500, Frank Li wrote:
> > > > > Add
> > > > > 	DWC_EPC_DEFAULT, into every epc_features.
> > > >
> > > > One corner case is that pci-layerscape-ep.c builds the pci_epc_features
> > >
> > > It is our old platform. I checked code, it should be wrong. features should
> > > report EPC hardware capibility.
> >
> > I'm not really sure whether commit cc255eb0bfbe ("PCI: layerscape: Modify
> > the way of getting capability with different PEX") was wrong.
> > Do you have a patch in mind?
> 
> I think it's wrong. And it doesn't impact your patch. Just leave it as it.
> we can add submap support later if need.

Adding a macro:
#define DWC_EPC_COMMON_FEATURES .dynamic_inbound_mapping = true

And including it in all the DWC glue drivers' epc_features sounds
fine to me.

Frank does have a point that if some glue driver ever has some random
errata or bad integration, it will be simpler for a single glue driver
to override the defaults.

The commit that adds subrange mapping support would then just
change the macro to something like:

#define DWC_EPC_COMMON_FEATURES .dynamic_inbound_mapping = true, \
				.subrange_mapping = true

Kind regards,
Niklas