On Sat, Apr 1, 2017 at 4:16 AM, zhichang.yuan <zhichang.yuan02@xxxxxxxxx> wrote: > > > On 04/01/2017 07:02 AM, Rafael J. Wysocki wrote: >> On Fri, Mar 31, 2017 at 8:52 AM, zhichang.yuan >> <yuanzhichang@xxxxxxxxxxxxx> wrote: >>> Hi, Rafael, >>> >>> Thanks for reviewing this! >>> >>> On 2017/3/31 4:31, Rafael J. Wysocki wrote: >>>> On Thursday, March 30, 2017 11:26:58 PM zhichang.yuan wrote: >>>>> On some platforms(such as Hip06/Hip07), the legacy ISA/LPC devices access I/O >>>>> with some special host-local I/O ports known on x86. To access the I/O >>>>> peripherals, an indirect-IO mechanism is introduced to mapped the host-local >>>>> I/O to system logical/fake PIO similar the PCI MMIO on architectures where no >>>>> separate I/O space exists. Just as PCI MMIO, the host I/O range should be >>>>> registered before probing the downstream devices and set up the I/O mapping. >>>>> But current ACPI bus probing doesn't support these indirect-IO hosts/devices. >>>>> >>>>> This patch introdueces a new ACPI handler for this device category. Through the >>>>> handler attach callback, the indirect-IO hosts I/O registration is done and >>>>> all peripherals' I/O resources are translated into logic/fake PIO before >>>>> starting the enumeration. >>>> >>>> Can you explain to me briefly what exactly this code is expected to be doing? >>> >>> As you know currently for ARM architecture IO space is memory mapped and >>> is only used by pci devices. The port number is dynamically allocated >>> converting the device IO address into a PIO token: i.e. >>> http://lxr.free-electrons.com/source/drivers/acpi/pci_root.c#L745 >>> This patch is meant to support a new class of IO host controller >>> that are not PCI based and that still require to have the IO addresses >>> be translated in the same PIO token space as the PCI controller >> >> IOW, this is ARM-specific, right? > > Yes. The current host added in this patch with _HID "HISI0191" is on ARM64. But the underlying mechanism is ARM-specific as well AFAICS. > But, I think the handler driver is architecture dependent. I guess you mean "independent"? That doesn't matter. If ARM64 is the only architecture to use it in foreseeable future (which is the case for all I can say), it should go into acpi/arm64/ and please ask the maintainers thereof to review it. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
