On Thu, Jan 14, 2016 at 12:32:03PM -0500, Mark Salter wrote: > On Thu, 2016-01-14 at 17:07 +0000, Lorenzo Pieralisi wrote: > > On Thu, Jan 14, 2016 at 11:38:44AM -0500, Mark Salter wrote: > > > > [...] > > > > > You would lose that bet. AddressMinimum/Maximum describe the > > > PCI bus addresses. > > > > In the mainline DT (APM Mustang), the CPU physical address corresponding > > to IO space is 0xe010000000, PCI bus address is 0x0. > > > > > QWordIO (ResourceProducer, MinFixed, MaxFixed, PosDecode, EntireRange, > > > 0x0000000000000000, // Granularity > > > 0x0000000010000000, // Range Minimum > > > > > > > 0x000000001000FFFF, // Range Maximum > > > 0x000000E000000000, // Translation Offset > > > > See above, I will get the APM specifications to countercheck. > > The spec won't help other than to verify that the PCIe bridge supports > a 32-bit IO address space. The firmware sets the PCI bus base @ > 0x10000000 with a CPU base address for that window @ 0xe010000000. The > pci-xgene.c driver sets the PCI bus IO base address to whatever DT > tells it too. For ACPI, we have to use whatever the firmware set it to > and described it in the ACPI table. It makes sense, thank you for clarifying (and sorry for jumping to conclusions, I am a bit worried about the ACPI IO space descriptors specification and usage on arm64). > When I looked at this a while back, neither ACPI nor PCI had anything > which disallowed 32-bit IO space on the PCI bus. The 16-bit limit is > an x86 limit in the instruction set. We should ask Jiang to remove that check or to make it x86 only (does current mainline - where the offset is added to the resource start/end - work on ia64 ?) Thanks, Lorenzo > > > > > I agree with you we have to verify if this IO space limitation is > > real or it is just an x86ism, in which case we remove that check. > > > > Lorenzo > > > 0x0000000000010000, // Length > > > ,, , TypeStatic) > > > > > > > > > > > > Jiang's patch: > > > > > > > > https://lkml.org/lkml/2015/12/16/249 > > > > > > > > parses the IO descriptors and stores the AddressMinimum, AddressMaximum > > > > in the IO resource (with AddressTranslation as offset which must be the > > > > *CPU* physical address mapping IO), from the log above it seems to me in > > > > AddressMinimum APM specifies the *CPU* physical address generating IO > > > > cycles. > > > > > > > > All in all, I was right to fear this would happen, and I already > > > > raised the point within the ACPI spec working group, ACPI IO > > > > descriptors specification is ambiguous and we must agree on how > > > > they have to be specified once for all. > > > > > > > > Lorenzo > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
