On Monday 07 July 2014, Liviu Dudau wrote: > On Sat, Jul 05, 2014 at 09:46:09PM +0100, Arnd Bergmann wrote: > > On Saturday 05 July 2014 14:25:52 Rob Herring wrote: > > > On Tue, Jul 1, 2014 at 1:43 PM, Liviu Dudau <Liviu.Dudau@xxxxxxx> wrote: > > > > The ranges property for a host bridge controller in DT describes > > > > the mapping between the PCI bus address and the CPU physical address. > > > > The resources framework however expects that the IO resources start > > > > at a pseudo "port" address 0 (zero) and have a maximum size of IO_SPACE_LIMIT. > > > > The conversion from pci ranges to resources failed to take that into account. > > > > > > I don't think this change is right. There are 2 resources: the PCI bus > > > addresses and cpu addresses. This function deals with the cpu > > > addresses. Returning pci addresses for i/o and cpu addresses for > > > memory is going to be error prone. We probably need both cpu and pci > > > resources exposed to host controllers. > > > > > > Making the new function only deal with i/o bus resources and naming it > > > of_pci_range_to_io_resource would be better. > > > > I think you are correct that this change by itself is will break existing > > drivers that rely on the current behavior of of_pci_range_to_resource, > > but there is also something wrong with the existing implementation: > > Either I'm very confused or I've managed to confuse everyone else. The I/O > resources described using CPU addresses *are* using "pseudo" port based > addresses (or at least that is my understanding and my reading of the code). > Can you point me to a function that is expecting the IO resource to have > the start address at the physical address of the mapped space? pci_v3_preinit() in arch/arm/mach-integrator/pci_v3.c for instance takes the resource returned by of_pci_range_to_resource and programs the start and size into hardware registers that expect a physical address as far as I can tell. > I was trying to fix exactly this issue, that you cannot use the resource > structure returned by this function in any call that is expecting an IO > resource. I looked at the other drivers briefly, and I think you indeed fix the Tegra driver with this but break the integrator driver as mentioned above. The other callers of of_pci_range_to_resource() are apparently not impacted as they recalculate the values they get. Arnd -- 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
