PCI: controller: Move PCI_DOMAINS selection to arch Kconfig

Commit 51bc085 ("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: 51bc085 ("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>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Scott Branden <scott.branden@broadcom.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Guenter Roeck <linux@roeck-us.net>

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

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

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

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.