| Message ID | 1411937610-22125-4-git-send-email-suravee.suthikulpanit@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Sunday 28 September 2014 15:53:29 suravee.suthikulpanit@amd.com wrote: > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index ce5836c..7fd4d2b 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -68,3 +68,11 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > bus->domain_nr = domain; > } > #endif > + > +int pcibios_enable_device(struct pci_dev *dev, int mask) > +{ > + if (pci_has_flag(PCI_PROBE_ONLY)) > + return 0; > + > + return pci_enable_resources(dev, mask); > +} This doesn't look arm64 specific to me, and there is already a generic pcibios_enable_device() function in drivers/pci/pci.c. Would it be possible to move the check for PCI_PROBE_ONLY there without breaking other architectures? If that works, please do so. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Sep 28, 2014 at 2:53 PM, <suravee.suthikulpanit@amd.com> wrote: > From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > > When specify PCI_PROBE_ONLY, the resource parent does not get assigned. > Therefore, pci_enable_resources() return error saying that > "BAR x not claimed". > > Note: This same logic is also used in the arch/arm/kernel/bios32.c > > Cc: Liviu Dudau <Liviu.Dudau@arm.com> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > --- > arch/arm64/kernel/pci.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index ce5836c..7fd4d2b 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -68,3 +68,11 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > bus->domain_nr = domain; > } > #endif > + > +int pcibios_enable_device(struct pci_dev *dev, int mask) > +{ > + if (pci_has_flag(PCI_PROBE_ONLY)) > + return 0; > + > + return pci_enable_resources(dev, mask); I had thought of "PCI_PROBE_ONLY" as the "look but don't touch" flag, i.e., never change any BAR or bridge window assignments. But I guess the current usage is more general than that: we also use it to - avoid pci_enable_resources(), which only turns on IO/MEM bits in the command register - avoid pcie_bus_configure_settings(), which programs MPS and MRRS - avoid pci_read_bridge_bases(), which really just *reads* bridge windows - avoid pcibios_reserve_legacy_regions(), which doesn't touch any PCI registers - enables pci_claim_resource() This seems like more than necessary, but I don't know all the history. In particular, I don't know why PCI_PROBE_ONLY should make a difference to things like claiming resources. > +} > -- > 1.9.3 >b -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, 2014-09-28 at 15:53 -0500, suravee.suthikulpanit@amd.com wrote: > From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > > When specify PCI_PROBE_ONLY, the resource parent does not get assigned. > Therefore, pci_enable_resources() return error saying that > "BAR x not claimed". > > Note: This same logic is also used in the arch/arm/kernel/bios32.c This looks broken. Why don't you assign the resource parent ? > Cc: Liviu Dudau <Liviu.Dudau@arm.com> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > --- > arch/arm64/kernel/pci.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index ce5836c..7fd4d2b 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -68,3 +68,11 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > bus->domain_nr = domain; > } > #endif > + > +int pcibios_enable_device(struct pci_dev *dev, int mask) > +{ > + if (pci_has_flag(PCI_PROBE_ONLY)) > + return 0; > + > + return pci_enable_resources(dev, mask); > +} -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 2014-09-29 at 12:17 -0600, Bjorn Helgaas wrote: > This seems like more than necessary, but I don't know all the history. > In particular, I don't know why PCI_PROBE_ONLY should make a > difference to things like claiming resources. It shouldn't ... we created that option on ppc originally to avoid allocation/reallocation of resources. If they are bad, leave them bad, but it was never a question of disabling all these other things. (Ok, the MRSS/MPS is debatable, but why not plumb the parent pointers and why not claim ? That doesn't make sense to me). Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jun 24, 2015 at 08:34:28AM +1000, Benjamin Herrenschmidt wrote: > On Mon, 2014-09-29 at 12:17 -0600, Bjorn Helgaas wrote: > > This seems like more than necessary, but I don't know all the history. > > In particular, I don't know why PCI_PROBE_ONLY should make a > > difference to things like claiming resources. > > It shouldn't ... we created that option on ppc originally to avoid > allocation/reallocation of resources. If they are bad, leave them bad, > but it was never a question of disabling all these other things. > > (Ok, the MRSS/MPS is debatable, but why not plumb the parent pointers > and why not claim ? That doesn't make sense to me). You could look back over the history of arch/arm/kernel/bios32.c and see that it was introduced by Will Deacon when he stripped out the ARM version in favour of the generic version, and was found to be necessary then. I think the question has to be asked (based upon what Ben's saying) and what's identified in these commits as a failure case (pci_enable_resource failing when PCI_PROBE_ONLY is enabled) - why is the PCI core creating per-device resources which do not have parents. I've no idea on that; the only ARM boxes I have use the kernel's PCI allocation, I don't have these boxes which want to use PCI_PROBE_ONLY so it's something I have zero knowledge of.
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index ce5836c..7fd4d2b 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -68,3 +68,11 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) bus->domain_nr = domain; } #endif + +int pcibios_enable_device(struct pci_dev *dev, int mask) +{ + if (pci_has_flag(PCI_PROBE_ONLY)) + return 0; + + return pci_enable_resources(dev, mask); +}