On Wed, Jun 13, 2018 at 11:11:46AM -0700, Guenter Roeck wrote:
> On Wed, Jun 13, 2018 at 11:09:35AM +0100, Lorenzo Pieralisi wrote:
> > [+Jan, Ley Foon, RMK]
> >
> > On Tue, Jun 12, 2018 at 10:02:29AM -0700, Guenter Roeck wrote:
> > > On Thu, Apr 05, 2018 at 02:31:54PM -0500, Rob Herring wrote:
> > > > Add COMPILE_TEST on driver config options with it. Some ARM drivers
> > > > still have arch dependencies, so we have to keep those dependent on ARM.
> > > >
> > > > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > > > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > > > Cc: linux-pci@xxxxxxxxxxxxxxx
> > > > Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> > >
> > > This patch has the undesirable side effect that it selects PCI_DOMAINS for
> > > sparc32:allmodconfig, which in turn results in
> > >
> > > 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'?
> > >
> > > Unfortunately, 37bd62d224c82 ("PCI: Enable PCI_DOMAINS along with generic
> > > PCI host controller") has pretty much the same result. No idea how to fix
> > > the problem, so I won't even try.
> >
> > Sorry about that.
> >
> > One option would consist in removing all PCI_DOMAINS selection from
> > drivers/pci/controller/Kconfig and delegate it to arches even though
> > this would force PCI_DOMAINS selection on all ARM platforms (it is
> > already selected for ARCH_MULTIPLATFORM).
> >
> > Or we add back arch dependency to the relevant host bridges.
> >
> > Everything else I have in mind seems overkill to me given that this
> > patch was added to improve test coverage (we could add a default
> > pci_domain_nr() stub - weak or #define - that returns 0 in case arches
> > do not provide an implementation but do we really want to do that ?).
> >
> > Thoughts appreciated.
> >
>
> From the definition of PCI_DOMAINS, I suspect the original idea was that
> drivers should depend on it, not select it. Especially auto-selecting
> it with PCI_HOST_GENERIC seems like a bad idea to me. However, that is
> just me. I'll leave it up to Bjorn to decide what if anything he wants
> to do about it.
Here is a patch that should reinstate the previous behaviour but
it will make PCI_DOMAINS a visible option on ARM 32-bit systems; whether
that's acceptable that's the question I need to answer, it should
honour old configs and it does not force PCI_DOMAINS selection on
non-DT arch/arm PCI host controllers (that do not need PCI_DOMAINS
anyway so I suspect that enabling it on all ARM 32-bit platforms
should not break anything but I preferred to be cautious).
If I hear no complaints I will post it for inclusion, we cannot leave
things as they are.
Lorenzo
-- >8 --
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2a78bdef9a24..1d415aeb54b4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1244,8 +1244,14 @@ 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/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.
--
2.15.0
