linux-kernel - Re: [RFC v1 01/16] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS

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Date:	Tue, 11 Dec 2012 16:15:02 +0000
From:	Arnd Bergmann <arnd@...db.de>
To:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Cc:	linux-arm-kernel@...ts.infradead.org,
	Jason Cooper <jason@...edaemon.net>,
	Andrew Lunn <andrew@...n.ch>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	Lior Amsalem <alior@...vell.com>,
	Yehuda Yitschak <yehuday@...vell.com>,
	Tawfik Bayouk <tawfik@...vell.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...onic-design.de>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	linux-kernel@...r.kernel.org,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	"Eran Ben-Avi" <benavi@...vell.com>,
	Nadav Haklai <nadavh@...vell.com>,
	Maen Suleiman <maen@...vell.com>,
	Shadi Ammouri <shadi@...vell.com>,
	Yinghai Lu <yinghai@...nel.org>
Subject: Re: [RFC v1 01/16] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS_IOPORT

On Tuesday 11 December 2012, Thomas Petazzoni wrote:
> On Tue, 11 Dec 2012 10:43:49 +0000, Arnd Bergmann wrote:
> > On Friday 07 December 2012, 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.
> > 
> > I think this one is wrong as the CONFIG_HAS_IOPORT does not refer to the
> > presence of PIO ports but to whether or not they provide an ioport_map
> > function. If there is no ioport_map(), devm_pci_iomap will fail to link
> > as far as I can tell.
> 
> The problem is that on ARCH_MULTI_V7, ARCH_VEXPRESS is forcefully
> enabled. And ARCH_VEXPRESS selects NO_IOPORT.. so you don't have the
> pcim_*() functions, and therefore libata-sff.c (needed for many SATA
> drivers) will not build. How do you solve this?

What you describe here are probable two bugs, and we should fix both:

* ARCH_VEXPRESS should not select NO_IOPORT. It's generally wrong
  to select this in combination with ARCH_MULTIPLATFORM, when some
  of the other platforms you may enable actually have IOPORT mapping
  support.

* We should not unconditionally select ARCH_VEXPRESS from ARCH_MULTIPLATFORM.
  There is no reason why we would enable that platform for building
  a kernel that runs on only one other platform.

> I'm not sure which devm_pci_iomap() you're referring to since my patch
> makes only the pcim_iomap_table(), pcim_iomap(), pcim_iounmap(),
> pcim_iomap_regions(), pcim_iomap_regions_request_all() and
> pcim_iounmap_regions() available under CONFIG_PCI instead of CONFIG_PCI
> && CONFIG_HAS_IOPORT.

Sorry, I meant pcim_iomap.

> So maybe you were referring to pcim_iomap(). I haven't checked in
> details, but I guess it builds because ioport_map() is implemented in
> arch/arm/mm/iomap.c.

Right. If an ioport_map function is provided for a given platform,
we should also set HAVE_IOPORT and vice versa. This is probably
fallout of the io.h conversion for multiplatform.

	Arnd
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