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Date:   Thu, 21 Jun 2018 17:54:00 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To:     Jan Kiszka <jan.kiszka@siemens.com>,
        Scott Branden <scott.branden@broadcom.com>,
        Ley Foon Tan <lftan@altera.com>
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        Will Deacon <will.deacon@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh@kernel.org>,
        Russell King <linux@armlinux.org.uk>,
        Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v2] PCI: controller: Move PCI_DOMAINS selection to arch
 Kconfig
Message-ID: <20180621165400.GB14519@e107981-ln.cambridge.arm.com>
References: <20180619112105.14457-1-lorenzo.pieralisi@arm.com>
 <30bb8a16-f829-a5a4-265f-2d1112d8d0bf@siemens.com>
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On Wed, Jun 20, 2018 at 10:07:33AM +0200, Jan Kiszka wrote:
> On 2018-06-19 13:21, Lorenzo Pieralisi wrote:
> > Commit 51bc085d6454 ("PCI: Improve host drivers compile test coverage")
> > added configuration options to allow PCI host controller drivers to be
> > compile tested on all architectures.
> > 
> > Some host controller drivers (eg PCIE_ALTERA) config entries select
> > the PCI_DOMAINS config option to enable PCI domains management in
> > the kernel. Now that host controller drivers can be compiled on
> > all architectures, this triggers build regressions on arches that
> > do not implement the PCI_DOMAINS required API (ie pci_domain_nr()):
> > 
> > drivers/ata/pata_ali.c: In function 'ali_init_chipset':
> > drivers/ata/pata_ali.c:469:38: error:
> >         implicit declaration of function 'pci_domain_nr';
> >                                           did you mean 'pci_iomap_wc'?
> > 
> > Furthemore, some software configurations (ie Jailhouse) require a
> > PCI_DOMAINS enabled kernel to configure multiple host controllers
> > without having an explicit dependency on the ARM platform on which
> > they run.
> > 
> > Make PCI_DOMAINS a visible configuration option on ARM so that software
> > configurations that need it can manually select it and move the
> > PCI_DOMAINS selection from PCI controllers configuration file to ARM
> > sub-arch config entries that currently require it, fixing the issue.
> > 
> > Fixes: 51bc085d6454 ("PCI: Improve host drivers compile test coverage")
> > Link: https://lkml.kernel.org/r/20180612170229.GA10141@roeck-us.net
> > Reported-by: Guenter Roeck <linux@roeck-us.net>
> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Cc: Scott Branden <scott.branden@broadcom.com>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Russell King <linux@armlinux.org.uk>
> > Cc: Jan Kiszka <jan.kiszka@siemens.com>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: Ley Foon Tan <lftan@altera.com>
> > ---
> > v1 -> v2
> > 	- Removed ARCH_VIRT PCI_DOMAINS selection
> > 	- Added PCI_DOMAINS visible config option
> > 
> > v1: https://marc.info/?l=linux-pci&m=152932092612352&w=2
> > 
> >  arch/arm/Kconfig               | 8 +++++++-
> >  arch/arm/mach-bcm/Kconfig      | 1 +
> >  arch/arm/mach-socfpga/Kconfig  | 1 +
> >  drivers/pci/controller/Kconfig | 3 ---
> >  4 files changed, 9 insertions(+), 4 deletions(-)
> > 
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 54eeb8d00bc6..843edfd000be 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1245,8 +1245,14 @@ config PCI
> >  	  VESA. If you have PCI, say Y, otherwise N.
> >  
> >  config PCI_DOMAINS
> > -	bool
> > +	bool "Support for multiple PCI domains"
> >  	depends on PCI
> > +	help
> > +	  Enable PCI domains kernel management. Say Y if your machine
> > +	  has a PCI bus hierarchy that requires more than one PCI
> > +	  domain (aka segment) to be correctly managed. Say N otherwise.
> > +
> > +	  If you don't know what to do here, say N.
> >  
> >  config PCI_DOMAINS_GENERIC
> >  	def_bool PCI_DOMAINS
> > diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
> > index c46a728df44e..25aac6ee2ab1 100644
> > --- a/arch/arm/mach-bcm/Kconfig
> > +++ b/arch/arm/mach-bcm/Kconfig
> > @@ -20,6 +20,7 @@ config ARCH_BCM_IPROC
> >  	select GPIOLIB
> >  	select ARM_AMBA
> >  	select PINCTRL
> > +	select PCI_DOMAINS if PCI
> >  	help
> >  	  This enables support for systems based on Broadcom IPROC architected SoCs.
> >  	  The IPROC complex contains one or more ARM CPUs along with common
> > diff --git a/arch/arm/mach-socfpga/Kconfig b/arch/arm/mach-socfpga/Kconfig
> > index d0f62eacf59d..4adb901dd5eb 100644
> > --- a/arch/arm/mach-socfpga/Kconfig
> > +++ b/arch/arm/mach-socfpga/Kconfig
> > @@ -10,6 +10,7 @@ menuconfig ARCH_SOCFPGA
> >  	select HAVE_ARM_SCU
> >  	select HAVE_ARM_TWD if SMP
> >  	select MFD_SYSCON
> > +	select PCI_DOMAINS if PCI
> >  
> >  if ARCH_SOCFPGA
> >  config SOCFPGA_SUSPEND
> > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> > index 18fa09b3ac8f..cc9fa02d32a0 100644
> > --- a/drivers/pci/controller/Kconfig
> > +++ b/drivers/pci/controller/Kconfig
> > @@ -96,7 +96,6 @@ config PCI_HOST_GENERIC
> >  	depends on OF
> >  	select PCI_HOST_COMMON
> >  	select IRQ_DOMAIN
> > -	select PCI_DOMAINS
> >  	help
> >  	  Say Y here if you want to support a simple generic PCI host
> >  	  controller, such as the one emulated by kvmtool.
> > @@ -138,7 +137,6 @@ config PCI_VERSATILE
> >  
> >  config PCIE_IPROC
> >  	tristate
> > -	select PCI_DOMAINS
> >  	help
> >  	  This enables the iProc PCIe core controller support for Broadcom's
> >  	  iProc family of SoCs. An appropriate bus interface driver needs
> > @@ -176,7 +174,6 @@ config PCIE_IPROC_MSI
> >  config PCIE_ALTERA
> >  	bool "Altera PCIe controller"
> >  	depends on ARM || NIOS2 || COMPILE_TEST
> > -	select PCI_DOMAINS
> >  	help
> >  	  Say Y here if you want to enable PCIe controller support on Altera
> >  	  FPGA.
> > 
> 
> Acked-by: Jan Kiszka <jan.kiszka@siemens.com>

Thanks a lot. Scott, Ley Foon, does it work for you ? I would like
to ask Bjorn to send it asap since the build on sparc is still broken.

Thanks,
Lorenzo