On Thu, Feb 9, 2012 at 8:34 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Thu, Feb 9, 2012 at 8:03 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >> On Thu, Feb 9, 2012 at 6:36 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: >>> There's a lot of PCI-related code under arch/, but much of it is not actually >>> architecture-specific. This series removes some of that code by moving most >>> of the bus-to-resource conversions into the core. >>> >>> We currently read PCI bus addresses from BARs in the core (pci_setup_device()). >>> Then every arch is responsible for converting those bus addresses to CPU >>> resources, usually in pcibios_fixup_bus(). >>> >>> We already have a way for architectures to tell the core what the windows >>> through a host bridge are: >>> >>> LIST_HEAD(resources); >>> pci_add_resource(&resources, io_space); >>> pci_add_resource(&resources, mem_space); >>> pci_scan_root_bus(parent, bus, ops, sysdata, &resources); >>> >>> This series extends that so the arch can also tell the core about address >>> translation performed by the host bridge: >>> >>> LIST_HEAD(resources); >>> pci_add_resource_offset(&resources, io_space, io_offset); >>> pci_add_resource_offset(&resources, mem_space, mem_offset); >>> pci_scan_root_bus(parent, bus, ops, sysdata, &resources); >>> >>> Given that offset (the difference between bus address and CPU address for >>> each aperture), the core can do the bus-to-resource conversion immediately >>> when it reads the BARs. >>> >>> This removes an opportunity for bugs (some PCI fixups currently see bus >>> addresses in struct pci_dev resources when they're expecting CPU addresses), >>> but the main reason to do this is to make our PCI resource handling simpler >>> and more uniform. >>> >>> These patches are also available in this git repo: >>> git://github.com/bjorn-helgaas/linux.git pci-offset-v2-d15af52258dd >>> >>> Or you can browse them here: >>> https://github.com/bjorn-helgaas/linux/compare/master...pci-offset-v2-d15af52258dd >>> >>> I'd like to get these into linux-next soon to be ready for the 3.4 merge >>> window, so please let me know if you see any issues. >>> >>> Changes since v1: >>> - mips: remove Cobalt legacy IDE fixup >>> - show bus address range, not offset, e.g., this: >>> pci_bus 0000:00: root bus resource [mem 0xf0000000000-0xf007edfffff] (bus address [0x80000000-0xfedfffff]) >>> instead of this: >>> pci_bus 0000:00: root bus resource [mem 0xf0000000000-0xf007edfffff] (bus offset 0xeff80000000) >>> >> >> still think make pci_sysdata to generic and add one offset field to >> that would be more simple. > > Maybe I'm misunderstanding you, because this doesn't make sense to me at all. > > *One* offset field is insufficient. A host bridge can have an > arbitrary number of apertures, and each aperture can have a different > offset. So we must have a list or other variable-size structure. > > pci_scan_bus() takes a "void *sysdata". Every arch defines its own > structure (struct pci_sysdata for x86, struct pci_controller for most > others) to supply here. Are you suggesting that we make a common > structure like this: > > struct pci_sysdata { > struct list_head windows; > void *sysdata; /* arch-specific stuff */ > }; > > That's possible, but I don't see the advantage over what I've done. > It doesn't seem simpler, because all the arch code that looks at > bus->sysdata would have to change to use > bus->generic_sysdata->sysdata. I mean, we can unify sysdata usuage, make them all most the same. and for some sysdata, already acting like host_bridge struct with domain, numa_node, and resources. > > If you can show an example of what you mean, maybe it will help me understand. just looked the sys_data of different arch, looks like pci_sys_data for arm already include the io offset arch/arm/include/asm/mach/pci.h:: struct pci_sys_data { #ifdef CONFIG_PCI_DOMAINS int domain; #endif struct list_head node; int busnr; /* primary bus number */ u64 mem_offset; /* bus->cpu memory mapping offset */ unsigned long io_offset; /* bus->cpu IO mapping offset */ struct pci_bus *bus; /* PCI bus */ struct list_head resources; /* root bus resources (apertures) Thanks Yinghai -- 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
