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

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

[Jingoo Han]

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On Wednesday, March 06, 2013 5:26 PM, Thomas Petazzoni wrote:
> 
> Dear Jingoo Han,
> 
> On Wed, 06 Mar 2013 06:28:08 +0000 (GMT), Jingoo Han wrote:
> 
> > Sorry, I did not know that you submitted the patch.
> 
> No problem, I'm happy to have one less patch to carry in my PCIe patch
> set :)

Thank you :)

> 
> > Like you, I am developing PCIe Host driver.
> 
> Just curious, do you already have some code? Thierry Reding and myself
> have been looking at each other's PCIe host driver since a while in
> order to make some consistent choices where possible. It would be good
> to see your code as well.

Yes, I am developing a PCIe driver for Samsung Exynos SoCs.
Also, 2 days ago, I submitted the PCIe driver.

http://www.spinics.net/lists/linux-pci/msg20548.html
http://www.spinics.net/lists/linux-pci/msg20549.html

If someone look at my code, it will be very helpful.
Thank you :)

Best regards,
Jingoo Han

> 
> Best regards,
> 
> Thomas
> --
> Thomas Petazzoni, Free Electrons
> Kernel, drivers, real-time and embedded Linux
> development, consulting, training and support.
> http://free-electrons.com
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Re: Re: [PATCH 05/32] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS_IOPORT

[Jingoo Han]

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On Tuesday, March 05, 2013 5:30 AM, Arnd Bergmann wrote:
> 
> 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.


Hi Thomas Petazzoni
Sorry, I did not know that you submitted the patch.
Like you, I am developing PCIe Host driver.
Also, I experienced the annoying build error related to
CONFIG_HAS_IOPORT.

Hi Arnd Bergmann,
I have just read the mailing thread.
If you resolve this situation properly, it will be very helpful.
Thank you.

Best regards,
Jingoo Han

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

[Thomas Petazzoni]

Dear Jingoo Han,

On Wed, 06 Mar 2013 06:28:08 +0000 (GMT), Jingoo Han wrote:

> Sorry, I did not know that you submitted the patch.

No problem, I'm happy to have one less patch to carry in my PCIe patch
set :)

> Like you, I am developing PCIe Host driver.

Just curious, do you already have some code? Thierry Reding and myself
have been looking at each other's PCIe host driver since a while in
order to make some consistent choices where possible. It would be good
to see your code as well.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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

[Thomas Petazzoni]

The pcim_*() functions are used by the libata-sff subsystem, and this
subsystem is used for many SATA drivers on ARM platforms that do not
necessarily have I/O ports.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
---
 lib/devres.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/devres.c b/lib/devres.c
index 80b9c76..5639c3e 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -195,6 +195,7 @@ void devm_ioport_unmap(struct device *dev, void __iomem *addr)
 			       devm_ioport_map_match, (void *)addr));
 }
 EXPORT_SYMBOL(devm_ioport_unmap);
+#endif /* CONFIG_HAS_IOPORT */
 
 #ifdef CONFIG_PCI
 /*
@@ -400,4 +401,3 @@ void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
 }
 EXPORT_SYMBOL(pcim_iounmap_regions);
 #endif /* CONFIG_PCI */
-#endif /* CONFIG_HAS_IOPORT */
-- 
1.7.9.5

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

[Arnd Bergmann]

On Tuesday 12 February 2013, Thomas Petazzoni wrote:
> The pcim_*() functions are used by the libata-sff subsystem, and this
> subsystem is used for many SATA drivers on ARM platforms that do not
> necessarily have I/O ports.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Cc: Yinghai Lu <yinghai@kernel.org>
> Cc: linux-kernel@vger.kernel.org

Sorry, but this patch is still incorrect. 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.

If a platform has no support for I/O ports at all, it should
probably not set CONFIG_NO_IOPORT at this point.

	Arnd

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

[Thomas Petazzoni]

Dear Arnd Bergmann,

On Tue, 12 Feb 2013 18:00:48 +0000, Arnd Bergmann wrote:
> On Tuesday 12 February 2013, Thomas Petazzoni wrote:
> > The pcim_*() functions are used by the libata-sff subsystem, and
> > this subsystem is used for many SATA drivers on ARM platforms that
> > do not necessarily have I/O ports.
> > 
> > Signed-off-by: Thomas Petazzoni
> > <thomas.petazzoni@free-electrons.com> Cc: Paul Gortmaker
> > <paul.gortmaker@windriver.com> Cc: Jesse Barnes
> > <jbarnes@virtuousgeek.org> Cc: Yinghai Lu <yinghai@kernel.org>
> > Cc: linux-kernel@vger.kernel.org
> 
> Sorry, but this patch is still incorrect.

I know, but the discussion was so huge on the first posting that it was
basically impossible to draw a conclusion out of it.

> 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.

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.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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

[Arnd Bergmann]

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)
+       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.

	Arnd

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

[Thomas Petazzoni]

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
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

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

[Arnd Bergmann]

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