Hi Arnd, On Mon, Dec 21, 2015 at 03:15:54PM +0100, Arnd Bergmann wrote: > On Monday 21 December 2015, Tomasz Nowicki wrote: > > On 21.12.2015 13:10, Lorenzo Pieralisi wrote: > > > On Fri, Dec 18, 2015 at 06:56:39PM +0000, okaya@xxxxxxxxxxxxxx wrote: > > > >> I have multiple root ports with the same IO port configuration in the > > >> current ACPI table. > > >> > > >> Root port 0 = IO range 0x1000-0x10FFF > > >> Root port 1 = IO range 0x1000-0x10FFF > > >> Root port 2 = IO range 0x1000-0x10FFF > > > > > > It is fine. You end up mapping for each of those a 4k window of the > > > virtual address space allocated to IO and that's what you will have in > > > the kernel PCI resources (not in the HW BARs though). If that was a problem > > > it would be even for the current DT host controllers eg: > > > > > > arch/arm64/boot/dts/apm/apm-storm.dtsi > > > > > > it should not be (again I will let Arnd comment on this since he may be > > > aware of issues encountered on other arches/platforms). > > > > > > > Root port 0 = IO range 0x1000-0x10FFF > > Root port 1 = IO range 0x1000-0x10FFF > > Root port 2 = IO range 0x1000-0x10FFF > > > > If above ranges are mapped into different CPU windows, then yes, it is fine. > > Ideally, they should all be the same CPU address so we only have to > map the window once, each device gets an address below 64K, and you > can have legacy port numbers (below 4K) on any bus, which is required > to make certain GPUs work. Can I ask you to elaborate on the above please ? Do you mean a single CPU physical address range mapping the whole PCI IO address space ? I did not quite get what you mean by "you can have legacy port numbers on any bus", I think it would be good to clarify so that we are all on the same page. Thanks a lot ! Lorenzo -- 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
