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Subject: Re: [PATCH v2] PCI: controller: Move PCI_DOMAINS selection to arch
 Kconfig
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jan Kiszka <jan.kiszka@siemens.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>
References: <20180619112105.14457-1-lorenzo.pieralisi@arm.com>
 <30bb8a16-f829-a5a4-265f-2d1112d8d0bf@siemens.com>
 <20180621165400.GB14519@e107981-ln.cambridge.arm.com>
From:   Scott Branden <scott.branden@broadcom.com>
Message-ID: <5e9b0aa4-ded1-725d-c401-49c13b7d5f9d@broadcom.com>
Date:   Thu, 21 Jun 2018 22:08:17 -0700
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On 18-06-21 09:54 AM, Lorenzo Pieralisi wrote:
> 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.
Change will have to be made for arm64 for ARCH_BCM_IPROC as well.
>
> Thanks,
> Lorenzo