On Wed, Jul 9, 2014 at 12:20 AM, Arnd Bergmann arnd@arndb.de wrote:
On Tuesday 08 July 2014, Bjorn Helgaas wrote:
I think my confusion is because your pci_register_io_range() and pci_addess_to_pci() implementations assume that every io_range starts at I/O port 0 on PCI (correct me if I'm wrong). I suspect that's why you don't save the I/O port number in struct io_range.
I think you are just misreading the code, but I agree it's hard to understand and I made the same mistake in my initial reply to the first version.
pci_register_io_range and pci_address_to_pci only worry about the mapping between CPU physical and Linux I/O address, they do not care which PCI port numbers are behind that. The mapping between PCI port numbers and Linux port numbers is done correctly in patch 8/9 in the pci_host_bridge_of_get_ranges() function.
Ah, I see now. Thanks for explaining this again (I see you explained it earlier; I just didn't understand it). Now that I see it, it *is* very slick to handle both MMIO and PIO spaces the same way.
Bjorn