On Wed, May 6, 2015 at 9:18 AM, Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote: > On Tue, May 05, 2015 at 04:53:46PM +0100, Will Deacon wrote: >> On Tue, May 05, 2015 at 03:02:12AM +0100, Jayachandran C wrote: >> > The current code in pci-host-generic.c uses pci_common_init_dev() >> > from the arch/arm/ to do a part of the PCI initialization, and this >> > prevents it from being used on arm64. >> > >> > The initialization done by pci_common_init_dev() that is really >> > needed by pci-host-generic.c can be done in the same file without >> > using the hw_pci API of ARM. >> > >> > The ARM platform requires a pci_sys_data as sysdata for the PCI bus, >> > this is be handled by setting up 'struct gen_pci' to embed a >> > pci_sys_data variable as the first element on the ARM platform. >> > >> > Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx> >> > --- >> > Here's v2 of the patches, this enables use of pci-host-generic on >> > arm64. >> > >> > This has been tested on both qemu and fast model for arm64, and on >> > qemu for arm32. >> > >> > v1->v2 >> > - Address comments from Arnd Bergmann and Lorenzo Pieralisi >> > - move contents of gen_pci_init to gen_pci_probe >> > - assign resources only when !probe_only >> > - tested on ARM32 with qemu option -M virt >> >> I tried this with an arm64 kernel running under kvmtool, but I get the >> following errors (a 32-bit ARM kernel does seem to work): >> >> PCI host bridge /pci ranges: >> IO 0x00000000..0x0000ffff -> 0x00000000 >> MEM 0x41000000..0x7fffffff -> 0x41000000 >> pci-host-generic 40000000.pci: PCI host bridge to bus 0000:00 >> pci_bus 0000:00: root bus resource [bus 00-01] >> pci_bus 0000:00: root bus resource [io 0x0000-0xffff] >> pci_bus 0000:00: root bus resource [mem 0x41000000-0x7fffffff] >> pci_bus 0000:00: scanning bus >> pci 0000:00:00.0: [1af4:1009] type 00 class 0xff0000 >> pci 0000:00:00.0: reg 0x10: [mem 0x41000000-0x410003ff] >> pci 0000:00:00.0: reg 0x14: [io 0x6200-0x65ff] >> pci 0000:00:00.0: reg 0x18: [mem 0x41000400-0x410005ff] >> pci 0000:00:01.0: [1af4:1009] type 00 class 0xff0000 >> pci 0000:00:01.0: reg 0x10: [mem 0x41000800-0x41000bff] >> pci 0000:00:01.0: reg 0x14: [io 0x6600-0x69ff] >> pci 0000:00:01.0: reg 0x18: [mem 0x41000c00-0x41000dff] >> pci_bus 0000:00: fixups for bus >> pci_bus 0000:00: bus scan returning with max=00 >> pci 0000:00:00.0: fixup irq: got 10 >> pci 0000:00:00.0: assigning IRQ 10 >> pci 0000:00:01.0: fixup irq: got 11 >> pci 0000:00:01.0: assigning IRQ 11 >> virtio-pci 0000:00:00.0: can't enable device: BAR 0 [mem 0x41000000-0x410003ff] not claimed >> virtio-pci: probe of 0000:00:00.0 failed with error -22 >> virtio-pci 0000:00:01.0: can't enable device: BAR 0 [mem 0x41000800-0x41000bff] not claimed >> virtio-pci: probe of 0000:00:01.0 failed with error -22 > > Ok, had a further look. > > Referring to this thread: > > https://lkml.org/lkml/2014/9/29/557 > > By looking at other architectures code, resources should be claimed > (ie requested) even when PCI_PROBE_ONLY is set. Alpha, Sparc and PowerPC > seem to do that, in slightly different fashions. > > I do not think, as Bjorn mentioned, that PCI_PROBE_ONLY should be used > to prevent enabling resources through a PCI command, which is what > pci_enable_resources does. > > What we can do, is providing a generic PCI layer API that allows claiming > resources for a specific PCI bus, something similar if not identical > to what is done on alpha: > > arch/alpha/kernel/pci.c pcibios_claim_one_bus() > > that is not alpha specific at all. That way, we can use the API to claim > bus resources instead of assigning them on PCI_PROBE_ONLY (I *think* > that alpha calls pci_assign_unassigned_resources() even if > PCI_PROBE_ONLY is set, it should be safe since resources are claimed > first so IIUC the PCI layer would revert to FW BAR configuration on > assignment failure). > > Bjorn, any opinion on this ? Putting together a patch is easy when > we agree on the solution. I would like claiming resources, i.e., pci_claim_resource(), to happen in the core instead of in arch code because it's not inherently arch-specific. I don't think it should depend on PCI_PROBE_ONLY. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html