[found this old mail in my drafts folder, might as well send it now] On Thursday, November 10, 2016 8:36:24 PM CET zhichang.yuan wrote: > Sorry! I can't catch your idea yet:( > > When to register the I/O range? Is it done just after the successfully > of_translate_address() during the children scanning? No, you do it when first finding the bus itself, just like we do for PCI host bridges. > If yes, when a child is scanning, there is no range data in arm64_extio_ops. The > addr_is_indirect_io() calling in of_get_isa_indirect_io() don't need. All we can > check is just whether the address to be translated is IO and is under a parent > device which has no 'ranges' property. The children should only be scanned after the I/O range has been registered for the parent. > > Your current version has > > > > if (arm64_extio_ops->pfout) \ > > arm64_extio_ops->pfout(arm64_extio_ops->devpara,\ > > addr, value, sizeof(type)); \ > > > > Instead, just subtract the start of the range from the logical > > port number to transform it back into a bus-local port number: > > > > if (arm64_extio_ops->pfout) \ > > arm64_extio_ops->pfout(arm64_extio_ops->devpara,\ > > addr - arm64_extio_ops->start, value, sizeof(type)); \ > > > I think there is some information needed sync. > In the old patch-set, we don't bypass the pci_address_to_pio() after > successfully of_translate_address(). In this way, we don't need to reserve any > PIO space for our LPC since the logical port are from the same mapping > algorithm. Based on this way, the port number in the device resource is logical > one, then we need to subtract the start of the resource to get back the > bus-local port. > > From V3, we don't apply the mapping based on pci_address_to_pio(), the > of_translate_address() return the bus-local port directly and store into > relevant device resource. So, in the current arm64_extio_ops->pfout(), the > reverse translation don't need anymore. The input "addr" is bus-local port now. Ok, so this would have to be changed again: If we want to support multiple bus domains, of_translate_address() must translate between the bus specific address and the general Linux I/O port number. Even without doing that, it seems nicer to not overlap the range of the first PCI host bridge. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
