Re: [PATCH 00/20] PCI: fix config and I/O Address space memory mappings

Lorenzo Pieralisi
2017-03-02T18:01:15Z

On Wed, Mar 01, 2017 at 05:18:27PM +0100, Arnd Bergmann wrote:
> On Mon, Feb 27, 2017 at 4:14 PM, Lorenzo Pieralisi
> <lorenzo.pieralisi@arm.com> wrote:
>
> > This patch series[1] addresses both issues in one go:
> >
> > - It updates the pci_remap_iospace() function to use a page mapping
> > that guarantees non-posted write transactions for I/O space addresses
> > - It adds a kernel API to remap PCI config space resources, so that
> > architecture can override it with a mapping implementation that
> > guarantees PCI specifications compliancy wrt non-posted write
> > configuration transactions
> > - It updates all PCI host controller implementations (and the generic
> > ECAM layer) to use the newly introduced mapping interface
> >
> > Tested on Juno ECAM based interface (DT/ACPI).
>
> This looks all good to me, nice work!

Thanks a lot Arnd. There is a pending issue to complete the series,
that is related to asm-generic/io.h, which is not included by all
arches, therefore, on top of adding a default inline for
pci_remap_cfg_space() in asm-generic/io.h I will have to patch
all arches that do not include asm-generic/io.h (eg x86) to
make the series completely functional - ie I will have to add a

#define pci_remap_cfgspace ioremap_nocache

in every given asm/io.h that does not include <asm-generic/io.h>

Another option would consist in adding the default inline for
pci_remap_cfg_space() in asm-generic/pci_iomap.h which seems to
be included by all arches.

I think the first option, even if it requires more extensive
patching is more complete but please all let me know how
you want me to fix this niggle, I am not sure I grasp the background
policy behind asm-generic files entirely so I'd better ask.

Thanks !
Lorenzo