Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API

[Tomasz Nowicki]

On 19.04.2016 15:06, Arnd Bergmann wrote:
> On Monday 18 April 2016 21:31:54 Tomasz Nowicki wrote:
> > Basically the whole content of pci-thunder-ecam.c and pci-thunder-pem.c.
> >
> > pci-thunder-ecam.c contains config space accessors. Similar for
> > pci-thunder-pem.c but it also has extra init call (it is now called
> > thunder_pem_init) which finds and maps related registers.
>
> They seem to do much more than just override the accessors, they actually
> change the contents of the config space as well. Is that really necessary
> on ACPI based systems as well?

Yes, the pci-thunder-ecam.c accessors are meant to emulate config space 
capabilities. They are necessary to synthesize EA capabilities (fixed 
PCI BARs), it wont work without this, for ACPI boot as well.

> Another idea: how about moving all of this logic into ACPI and calling
> some AML method to access the config space if the devices are that
> far out of spec.

Do you mean Linux specific way to call non-standard config space 
accessors? Then non-standard accessors are going to AML methods which 
are called from common code which handles quirks via unified API ?

Thanks,
Tomasz