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

[Tomasz Nowicki]

On 18.04.2016 16:44, Arnd Bergmann wrote:
> On Monday 18 April 2016 15:03:51 Tomasz Nowicki wrote:
> > On 16.04.2016 16:36, Jayachandran C wrote:
> > > On Sat, Apr 16, 2016 at 1:01 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > > > On Saturday 16 April 2016 12:50:13 Jayachandran C wrote:
> > > The whole pci-thunder-*.c is to support thunder PCI quirks since the
> > > generic OF is handled by pci-host-common.c and generic ECAM is now
> > > separated -  duplicating the whole file for ACPI will be bad.
> >
> > Yes, it would be too much code duplication. Also, we already know
> > drivers which need quirks.
> >
> > We really need to agree on best approach here. Here are requirements
> > which came up (please correct me if misunderstood sth):
> >
> > Arnd:
> > 1. Initial DT driver should be standalone [Arnd]
> > 2. No exported symbols [Arnd]
> > 3. Duplicate necessary code to ACPI framework.
>
> Correct.
>
> > JC:
> > 1. Adding linker section is wrong.
> > 2. Quirks should be exported (pci_thunder_ecam_ops), then no need for
> > adding linker section
> > 3. To much duplication to copy code into the ACPI framework.
> >
> > My opinion:
> > 1. I like linker section because it is easy to maintain and no need to
> > export symbols.
> > 2. We need more sophisticated algorithm for matching quirks (DMI is not
> > enough and not only for ThunderX drivers). Of course I am open to any
> > new suggestions.
>
> Agreed.
>
> > 3. To much duplication to copy code into the ACPI framework.
> >
> > Thanks in advance for any pointers.
>
> Can you be more specific about what code actually would need to
> be duplicated? Anything besides the config space operations?

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.

Thanks,
Tomasz