Re: [PATCH V6 03/13] x86, ia64: Include acpi_pci_{add|remove}_bus to the default pcibios_{add|remove}_bus implementation.

[Tomasz Nowicki]

On 27.04.2016 04:34, Bjorn Helgaas wrote:
> On Fri, Apr 15, 2016 at 07:06:38PM +0200, Tomasz Nowicki wrote:
> > x86 and ia64 are the only arches that implement pcibios_{add|remove}_bus hooks
> > and implement them in the same way. Moreover ARM64 is going to do the same.
> > So it seems that acpi_pci_{add|remove}_bus is generic enough to be default
> > option for pcibios_{add|remove}_bus hooks. Also, it is always safe to run
> > acpi_pci_{add|remove}_bus as they have empty stubs for !ACPI case and
> > return if ACPI has been switched off in run time.
> >
> > After all we can remove x86 and ia64 pcibios_{add|remove}_bus
> > implementation.
> >
> > Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> > Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > Tested-by: Duc Dang <dhdang@xxxxxxx>
> > Tested-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> > Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > Tested-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > Tested-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> > ---
> >   arch/ia64/pci/pci.c   | 10 ----------
> >   arch/x86/pci/common.c | 10 ----------
> >   drivers/pci/probe.c   |  3 +++
> >   3 files changed, 3 insertions(+), 20 deletions(-)
> >
> > diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
> > index 978d6af..be4c9ef 100644
> > --- a/arch/ia64/pci/pci.c
> > +++ b/arch/ia64/pci/pci.c
> > @@ -358,16 +358,6 @@ void pcibios_fixup_bus(struct pci_bus *b)
> >   	platform_pci_fixup_bus(b);
> >   }
> >
> > -void pcibios_add_bus(struct pci_bus *bus)
> > -{
> > -	acpi_pci_add_bus(bus);
> > -}
> > -
> > -void pcibios_remove_bus(struct pci_bus *bus)
> > -{
> > -	acpi_pci_remove_bus(bus);
> > -}
> > -
> >   void pcibios_set_master (struct pci_dev *dev)
> >   {
> >   	/* No special bus mastering setup handling */
> > diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> > index 381a43c..7763a84 100644
> > --- a/arch/x86/pci/common.c
> > +++ b/arch/x86/pci/common.c
> > @@ -170,16 +170,6 @@ void pcibios_fixup_bus(struct pci_bus *b)
> >   		pcibios_fixup_device_resources(dev);
> >   }
> >
> > -void pcibios_add_bus(struct pci_bus *bus)
> > -{
> > -	acpi_pci_add_bus(bus);
> > -}
> > -
> > -void pcibios_remove_bus(struct pci_bus *bus)
> > -{
> > -	acpi_pci_remove_bus(bus);
> > -}
> > -
> >   /*
> >    * Only use DMI information to set this if nothing was passed
> >    * on the kernel command line (which was parsed earlier).
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 8087297..ef569e8 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -12,6 +12,7 @@
> >   #include <linux/slab.h>
> >   #include <linux/module.h>
> >   #include <linux/cpumask.h>
> > +#include <linux/pci-acpi.h>
> >   #include <linux/pci-aspm.h>
> >   #include <linux/aer.h>
> >   #include <linux/acpi.h>
> > @@ -2101,10 +2102,12 @@ int __weak pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
> >
> >   void __weak pcibios_add_bus(struct pci_bus *bus)
> >   {
> > +	acpi_pci_add_bus(bus);
> >   }
> >
> >   void __weak pcibios_remove_bus(struct pci_bus *bus)
> >   {
> > +	acpi_pci_remove_bus(bus);
> >   }
>
> Is this buying us something more than just getting rid of these
> pcibios functions in the arches?  The arch-specific pcibios methods
> by themselves don't seem too onerous, and I don't really want to add
> #includes and calls to every firmware interface under the sun.
>
> I admit it's a net removal of 17 lines, but I'm not sure it's a net
> reduction in complexity for the reader, who now has to remember that
> this ACPI stuff is a no-op on most arches.
>
> As a tangent, some of the stuff in acpi_pci_add_bus() really belongs
> elsewhere anyway.  For example, the _DSM stuff should probably be in
> acpi_pci_root_create() since it's a one-per-host bridge kind of thing.

OK, I will add pcibios_add_bus to ARM64 arch code and call 
acpi_pci_remove_bus(bus) from there.

Thanks,
Tomasz