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

login
register
mail settings
Submitter Arnd Bergmann
Date Feb. 12, 2013, 10:36 p.m.
Message ID <201302122236.37491.arnd@arndb.de>
Download mbox | patch
Permalink /patch/220006/
State Not Applicable
Headers show

Comments

Arnd Bergmann - Feb. 12, 2013, 10:36 p.m.
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:


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

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Thomas Petazzoni - March 4, 2013, 4:28 p.m.
Dear Arnd Bergmann,

On Tue, 12 Feb 2013 22:36:37 +0000, Arnd Bergmann wrote:

> > 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)
> +       if (IS_ENABLED(CONFIG_HAS_IOPORT) && (flags & IORESOURCE_IO))
>                 return __pci_ioport_map(dev, start, len);
>         if (flags & IORESOURCE_MEM) {
>                 if (flags & IORESOURCE_CACHEABLE)
> 
> in order to prevent a link error when CONFIG_HAS_IOPORT is unset.

FWIW, a patch that is doing what I was initially proposing has been
merged for 3.9, and it doesn't contain the
IS_ENABLED(CONFIG_HAS_IOPORT) test you were proposing (and which I
think was correct). See:

commit 9ed8a30f3471347c1b763bd062fa78ae80f18eae
Author: Jingoo Han <jg1.han@samsung.com>
Date:   Wed Feb 27 17:02:42 2013 -0800

Best regards,

Thomas
Arnd Bergmann - March 4, 2013, 8:30 p.m.
On Monday 04 March 2013, Thomas Petazzoni wrote:
> FWIW, a patch that is doing what I was initially proposing has been
> merged for 3.9, and it doesn't contain the
> IS_ENABLED(CONFIG_HAS_IOPORT) test you were proposing (and which I
> think was correct). See:
> 
> commit 9ed8a30f3471347c1b763bd062fa78ae80f18eae
> Author: Jingoo Han <jg1.han@samsung.com>
> Date:   Wed Feb 27 17:02:42 2013 -0800
> 

Sigh.

I'll take it as an additional incentive to finally clean up the logic behind
CONFIG_HAS_IOPORT by introducing a CONFIG_HAS_IOPORT_MAP symbol to replace it.

Thanks for the heads up.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

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)
+       if (IS_ENABLED(CONFIG_HAS_IOPORT) && (flags & IORESOURCE_IO))
                return __pci_ioport_map(dev, start, len);
        if (flags & IORESOURCE_MEM) {
                if (flags & IORESOURCE_CACHEABLE)