On 08/14/2012 04:58 PM, Stephen Warren wrote: > On 08/14/2012 03:55 PM, Bjorn Helgaas wrote: >> On Tue, Aug 14, 2012 at 12:58 PM, Thierry Reding >> <thierry.reding@xxxxxxxxxxxxxxxxx> wrote: >>> On Tue, Aug 14, 2012 at 01:39:23PM -0600, Stephen Warren wrote: >>>> On 08/13/2012 05:18 PM, Bjorn Helgaas wrote: >>>>> On Mon, Aug 13, 2012 at 11:47 AM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: >>>> ... >>>>>> whereas for a device tree boot: >>>>>> >>>>>> (same): >>>>>>> [ 2.112217] pci 0000:01:00.0: reg 10: [io 0x0000-0x00ff] >>>>>>> [ 2.117635] pci 0000:01:00.0: reg 18: [mem 0x00000000-0x00000fff 64bit pref] >>>>>>> [ 2.124690] pci 0000:01:00.0: reg 20: [mem 0x00000000-0x00003fff 64bit pref] >>>>>>> [ 2.131731] pci 0000:01:00.0: reg 30: [mem 0x00000000-0x0001ffff pref] >>>>>> ... (request region happens early) >>>>>>> [ 2.179838] r8169 0000:01:00.0: BAR 0: requesting [io 0x0000-0x00ff] >>>>>>> [ 2.193312] r8169 0000:01:00.0: BAR 2: requesting [mem 0x00000000-0x00000fff 64bit pref] >>>>>>> [ 2.201397] r8169 0000:01:00.0: BAR 2: can't reserve [mem 0x00000000-0x00000fff 64bit pref] >>>>>>> [ 2.209742] r8169 0000:01:00.0: (unregistered net_device): could not request regions >>>>>> ... (same, just happens too late) >>>>>>> [ 2.236818] pci 0000:01:00.0: BAR 6: assigned [mem 0xa0000000-0xa001ffff pref] >>>>>>> [ 2.244027] pci 0000:01:00.0: BAR 4: assigned [mem 0xa0020000-0xa0023fff 64bit pref] >>>>>>> [ 2.251794] pci 0000:01:00.0: BAR 2: assigned [mem 0xa0024000-0xa0024fff 64bit pref] >>>>>>> [ 2.259542] pci 0000:01:00.0: BAR 0: assigned [io 0x1000-0x10ff] >>>>>> >>>>>> I suspect this is all still related to the PCI devices themselves being >>>>>> probed much earlier in the overall PCI initialization sequence when the >>>>>> PCI controller is probed later in the boot sequence, whereas PCI device >>>>>> probe is deferred until the overall PCI initialization sequence is >>>>>> complete if the PCI controller is probed very early in the boot sequence. >>>>> >>>>> I don't know what to apply your patches to (they don't apply cleanly >>>>> to v3.6-rc2), so I can't see exactly what you're doing. But it looks >>>>> like you might be calling pci_bus_add_devices() before >>>>> pci_bus_assign_resource(), which isn't going to work. >>>> >>>> Yes, that's exactly what is happening. >>>> >>>> PCIe initialization starts in arch/arm/mach-tegra/pci.e >>>> tegra_pcie_init() which calls arch/arm/kernel/bios32.c >>>> pci_common_init(). That function first calls pcibios_init_hw() (in the >>>> same file, more about this later) and then loops over PCI buses, calling >>>> amongst other things pci_bus_assign_resources() then pci_bus_add_devices(). >>>> >>>> The problem is that ARM's pcibios_init_hw() calls pci_scan_root_bus() >>>> (or a host-driver-specific function which that also calls >>>> pci_scan_root_bus() in Tegra's case) which in turn calls >>>> pci_bus_add_devices() right at the end, before control has returned to >>>> pci_common_init() and hence before pci_bus_assign_resources() has been >>>> called. >>>> >>>> If I modify pci_scan_root_bus() and remove the call to >>>> pci_bus_add_devices(), everything works as expected. >>>> >>>> So, I guess the question is: Should ARM's pcibios_init_hw() not be >>>> calling pci_scan_root_bus(), or at least presumably the ARM PCI code >>>> needs to do things in a slightly different order? >> >> I think you need to do something like this instead of using pci_scan_root_bus(): >> >> pci_create_root_bus() >> pci_scan_child_bus() >> pci_bus_assign_resources() >> pci_bus_add_devices() >> >> This is the effective order used by most of the pci_create_root_bus() callers. > > That would pretty much duplicate everything in pci_scan_root_bus(). That > might cause divergence down the road. > > Can't we make the call to pci_bus_add_devices() optional in > pci_scan_root_bus() somehow; one of: Sigh, that turns out not to work correctly; it solves at least this part of the problem when booting using device tree, but when booting using a board file, it causes the IRQ number passed to the PCIe device to be bogus:-( I give up for now. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
