On Thursday, November 10, 2016 3:36:49 PM CET Gabriele Paoloni wrote: > > Where should we get the range from? For LPC we know that it is going > Work on anything that is not used by PCI I/O space, and this is > why we use [0, PCIBIOS_MIN_IO] It should be allocated the same way we allocate PCI config space segments. This is currently done with the io_range list in drivers/pci/pci.c, which isn't perfect but could be extended if necessary. Based on what others commented here, I'd rather make the differences between ISA/LPC and PCI I/O ranges smaller than larger. > > 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: > > These accessors do not operate on IO tokens: > > If (arm64_extio_ops->start > addr || arm64_extio_ops->end < addr) > addr is not going to be an I/O token; in fact patch 2/3 imposes that > the I/O tokens will start at PCIBIOS_MIN_IO. So from 0 to PCIBIOS_MIN_IO > we have free physical addresses that the accessors can operate on. Ah, I missed that part. I'd rather not use PCIBIOS_MIN_IO to refer to the logical I/O tokens, the purpose of that macro is really meant for allocating PCI I/O port numbers within the address space of one bus. Note that it's equally likely that whichever next platform needs non-mapped I/O access like this actually needs them for PCI I/O space, and that will use it on addresses registered to a PCI host bridge. If we separate the two steps: a) assign a range of logical I/O port numbers to a bus b) register a set of helpers for redirecting logical I/O port to a helper function then I think the code will get cleaner and more flexible. It should actually then be able to replace the powerpc specific implementation. 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
