On Thu, 28 Nov 2013 16:41:21 +0000, Leif Lindholm <leif.lindholm@xxxxxxxxxx> wrote: > This patch provides documentation of the [U]EFI runtime service and > configuration features for the arm architecture. > > Changes since v1/v2: > - Complete rewrite. > - New FDT bindings. > > Cc: Rob Landley <rob@xxxxxxxxxxx> > Cc: linux-doc@xxxxxxxxxxxxxxx > > Signed-off-by: Leif Lindholm <leif.lindholm@xxxxxxxxxx> Acked-by: Grant Likely <grant.likely@xxxxxxxxxx> With a few minor comments below. g. > --- > Documentation/arm/00-INDEX | 3 +++ > Documentation/arm/uefi.txt | 61 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > create mode 100644 Documentation/arm/uefi.txt > > diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX > index 36420e1..b3af704 100644 > --- a/Documentation/arm/00-INDEX > +++ b/Documentation/arm/00-INDEX > @@ -34,3 +34,6 @@ nwfpe/ > - NWFPE floating point emulator documentation > swp_emulation > - SWP/SWPB emulation handler/logging description > + > +uefi.txt > + - [U]EFI configuration and runtime services documentation > diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt > new file mode 100644 > index 0000000..9ba59509 > --- /dev/null > +++ b/Documentation/arm/uefi.txt > @@ -0,0 +1,61 @@ > +UEFI, the Unified Extensible Firmware Interface is, a specification Nit: Comma in the wrong place. > +governing the behaviours of compatible firmware interfaces. It is > +maintained by the UEFI Forum - http://www.uefi.org/. > + > +UEFI is an evolution of its predecessor 'EFI', so the terms EFI and > +UEFI are used somewhat interchangeably in this document and associated > +source code. As a rule, anything new uses 'UEFI', whereas 'EFI' refers > +to legacy code or specifications. > + > +UEFI support in Linux > +===================== > +Booting on a platform with firmware compliant with the UEFI specification > +makes it possible for the kernel to support additional features: > +- UEFI Runtime Services > +- Retrieving various configuration information through the standardised > + interface of UEFI configuration tables. (ACPI, SMBIOS, ...) > + > +For actually enabling [U]EFI support, enable: > +- CONFIG_EFI=y > +- CONFIG_EFI_VARS=y or m > + > +The implementation depends on receiving information about the UEFI environment > +in a Flattened Device Tree (FDT) - so is only available with CONFIG_OF. > + > +UEFI stub > +========= > +The "stub" is a feature that turns the Image/zImage into a valid UEFI PE/COFF Nit: s/turns/extends/ > +executable, including a loader application that makes it possible to load the > +kernel directly from the UEFI shell, boot menu, or one of the lightweight > +bootloaders like Gummiboot or rEFInd. > + > +The kernel image built with stub support remains a valid kernel image for > +booting in non-UEFI environments. > + > +UEFI kernel support on ARM > +========================== > +UEFI kernel support on the ARM architectures (arm and arm64) is only available > +when boot is performed through the stub. > + > +The stub populates the FDT /chosen node with (and the kernel scans for) the > +following parameters: > +________________________________________________________________________________ > +Name | Size | Description > +================================================================================ > +linux,uefi-system-table | 64-bit | Physical address of the UEFI System Table. > +-------------------------------------------------------------------------------- > +linux,uefi-mmap-start | 64-bit | Physical address of the UEFI memory map, > + | | populated by the UEFI GetMemoryMap() call. > +-------------------------------------------------------------------------------- > +linux,uefi-mmap-size | 32-bit | Size in bytes of the UEFI memory map > + | | pointed to in previous entry. > +-------------------------------------------------------------------------------- > +linux,uefi-mmap-desc-size | 32-bit | Size in bytes of each entry in the UEFI > + | | memory map. > +-------------------------------------------------------------------------------- > +linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format. > +-------------------------------------------------------------------------------- > +linux,uefi-stub-kern-ver | string | Copy of linux_banner from build. > +-------------------------------------------------------------------------------- > + > +For verbose debug messages, specify 'uefi_debug' on the kernel command line. > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
