Messages in this thread | | | Date | Fri, 12 Jun 2015 01:04:34 -0700 | From | Guenter Roeck <> | Subject | Re: [RFC/RFT PATCH v2] PCI: move pci_read_bridge_bases to the generic PCI layer |
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On 06/09/2015 02:01 AM, Lorenzo Pieralisi wrote: > When a PCI bus is scanned, upon PCI bridge detection the kernel > has to read the bridge registers to set-up its resources so that > the PCI resource hierarchy can be validated properly. > > Most if not all architectures read PCI bridge registers in the > pcibios_fixup_bus hook, that is called by the PCI generic layer > whenever a PCI bus is scanned. > > Since pci_read_bridge_bases is an arch agnostic operation (and it > is carried out on all architectures) it can be moved to the generic > PCI layer in order to consolidate code and remove the respective > calls from the architectures back-ends. > > The PCI_PROBE_ONLY flag is not checked before calling > pci_read_bridge_buses in the generic layer since reading the bridge > bases is not related to resources assignment; this implies that it > can be carried out safely on PCI_PROBE_ONLY systems too and should > not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY > flag before reading the bridge bases. > > In order to validate the resource hierarchy as soon as the resources > themselves are probed (ie read from the bridge), this patch also adds > code to pci_read_bridge_bases that claims the bridge resources, so that > they are validated and inserted in the resource hierarchy as soon as > the bridge bases are probed. > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > Cc: Ralf Baechle <ralf@linux-mips.org> > Cc: James E.J. Bottomley <jejb@parisc-linux.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Richard Henderson <rth@twiddle.net> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: David Howells <dhowells@redhat.com> > Cc: Russell King <linux@arm.linux.org.uk> > Cc: Tony Luck <tony.luck@intel.com> > Cc: David S. Miller <davem@davemloft.net> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: Michal Simek <monstr@monstr.eu> > Cc: Chris Zankel <chris@zankel.net>
Working fine on powerpc (tested with Freescale P2020 and P5020) as well as x86 (tested on two different server class systems).
Tested-by: Guenter Roeck <linux@roeck-us.net>
Guenter
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