Re: [PATCH 05/32] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS_IOPORT

From: Arnd Bergmann
Date: Tue Feb 12 2013 - 17:37:46 EST

On Tuesday 12 February 2013, Thomas Petazzoni wrote:
> > Any driver that requires a
> > linear mapping of I/O ports to __iomem pointers must depend
> > CONFIG_HAS_IOPORT with the current definition of that symbol (as
> > mentioned before, we should really rename that to
> > CONFIG_HAS_IOPORT_MAP). Having these functions not defined is a
> > compile time check that is necessary to ensure that all drivers have
> > the correct annotation.
> I have the feeling that the problem is more complex than that. My
> understanding is that the pcim_iomap_regions() function used by
> drivers/ata/libata-sff.c can perfectly be used to map memory BARs, and
> not necessarily I/O BARs. Therefore, this driver can perfectly be used
> in an architecture where CONFIG_NO_IOPORT is selected.

That is correct.

> The thing is that pcim_iomap_regions() transparently allows to remap an
> I/O BAR is such a BAR is passed as argument, or a memory BAR if such a
> BAR is passed as argument.
> Therefore, I continue to believe that the pcim_*() functions are useful
> even if the platform doesn't have CONFIG_HAS_IOPORT.

Yes, the pcim_ functions are useful in principle, but it falls back
to the __pci_ioport_map() for IORESOURCE_IO, and that needs to
return an error if CONFIG_HAS_IOPORT is not set.
I think it would be correct if you add this hunk:

diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c
index 0d83ea8..f9b6387 100644
--- a/lib/pci_iomap.c
+++ b/lib/pci_iomap.c
@@ -33,7 +33,7 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
return NULL;
if (maxlen && len > maxlen)
len = maxlen;
- if (flags & IORESOURCE_IO)
return __pci_ioport_map(dev, start, len);
if (flags & IORESOURCE_MEM) {

in order to prevent a link error when CONFIG_HAS_IOPORT is unset.

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