On Thu, Jul 24, 2014 at 02:19:14PM -0700, Randy Dunlap wrote: > On 07/24/2014 02:16 PM, Naresh Bhat wrote: > > > > On 24 July 2014 18:30, Hanjun Guo <hanjun....@linaro.org > > <mailto:hanjun....@linaro.org>> wrote: > > > > From: Graeme Gregory <graeme.greg...@linaro.org > > <mailto:graeme.greg...@linaro.org>> > > > > Add documentation for the guidelines of how to use ACPI > > on ARM64. > > > > Signed-off-by: Graeme Gregory <graeme.greg...@linaro.org > > <mailto:graeme.greg...@linaro.org>> > > Signed-off-by: Hanjun Guo <hanjun....@linaro.org > > <mailto:hanjun....@linaro.org>> > > --- > > Documentation/arm64/arm-acpi.txt | 240 > > ++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 240 insertions(+) > > create mode 100644 Documentation/arm64/arm-acpi.txt > > > > diff --git a/Documentation/arm64/arm-acpi.txt > > b/Documentation/arm64/arm-acpi.txt > > new file mode 100644 > > index 0000000..12cd550 > > --- /dev/null > > +++ b/Documentation/arm64/arm-acpi.txt > > @@ -0,0 +1,240 @@ > > +ACPI on ARMv8 Servers > > +--------------------- > > + > > +ACPI will be used for ARMv8 general purpose servers designed to follow > > +the SBSA specification (currently available to people with an ARM > > login at > > +http://silver.arm.com) > > + > > +The implemented ACPI version is 5.1 + errata as released by the UEFI > > Forum, > > +which is available at <http://www.uefi.org/acpi/specs>. > > + > > +If the machine does not meet these requirements then it is likely that > > Device > > +Tree (DT) is more suitable for the hardware. > > + > > +Relationship with Device Tree > > +----------------------------- > > + > > +ACPI support in drivers and subsystems for ARMv8 should never be > > mutually > > +exclusive with DT support at compile time. > > + > > +At boot time the kernel will only use one description method depending > > on > > +parameters passed from the bootloader. > > + > > +Regardless of whether DT or ACPI is used, the kernel must always be > > capable > > +of booting with either scheme. > > + > > +When booting using ACPI tables the /chosen node in DT will still be > > parsed > > +to extract the kernel command line and initrd path. No other section of > > +the DT will be used. > > + > > +Booting using ACPI tables > > +------------------------- > > + > > +Currently, the only defined method to pass ACPI tables to the kernel > > on ARMv8 > > +is via the UEFI system configuration table. > > + > > +The UEFI implementation MUST set the ACPI_20_TABLE_GUID to point to the > > +RSDP table (the table with the ACPI signature "RSD PTR "). > > + > > +The pointer to the RSDP table will be retrieved from EFI by the ACPI > > core. > > + > > +Processing of ACPI tables may be disabled by passing acpi=off on the > > kernel > > +command line. > > + > > +DO use an XSDT, RSDTs are deprecated and should not be used on arm64. > > They > > +only allow for 32bit addresses. > > + > > +DO NOT use the 32-bit address fields in the FADT, they are deprecated, > > the > > +64-bit alternatives MUST be used. > > + > > +The minimum set of tables MUST include RSDP, XSDT, FACS, FADT, DSDT, > > MADT > > +and GTDT. If PCI is used the MCFG table MUST also be present. > > + > > +ACPI Detection > > +-------------- > > + > > +Drivers should determine their probe() type by checking for > > ACPI_HANDLE, > > +or .of_node, or other information in the device structure. This is > > +detailed further in the "Driver Recomendations" section. > > + > > +If the presence of ACPI needs to be detected at runtime, then check > > the value > > +of acpi_disabled. If CONFIG_ACPI not being set acpi_disabled will > > always be 1. > > + > > +Device Enumeration > > +------------------ > > + > > +Device descriptions in ACPI should use standard recognised ACPI > > interfaces. > > > > > > recognized > > Yeah, I saw all of these also, but we accept British or American spelling of > these words. > Would be good to check for a consistent spelling in this doc though.
-Christoffer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
