Hi, Arnd, On 2016/11/11 0:07, Arnd Bergmann wrote: > 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 > It seems that we need to add a new bus and the corresponding resource management which can also cover current PCI pio mapping, is it right? Thanks, Zhichang > 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
