Describe details of how to pass a DTB from firmware to the OS. Specifies the GUID for passing the DTB via the EFI_SYSTEM_TABLE and the memory type needs to be EfiACPIReclaimMemory.
Fixes: #45 Cc: Andrei Warkentin awarkentin@vmware.com Cc: Francois Ozog francois.ozog@linaro.org Cc: Ard Biesheuvel ardb@kernel.org Signed-off-by: Grant Likely grant.likely@arm.com --- source/chapter2-uefi.rst | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index c42691b..2b52afe 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -86,6 +86,18 @@ tables. - An Advanced Configuration and Power Interface [ACPI]_ table, or - a Devicetree [DTSPEC]_ system description
+A Devicetree system description must be provided in Flattened Devicetree (DTB) +format version 17 or higher as described in [DTSPEC]_ § 5.1. +The following GUID must be used in the EFI system table ([UEFI]_ § 4) +to identify the DTB. +The DTB must be contained in memory of type EfiACPIReclaimMemory. + +.. code-block:: c + + #define EFI_DTB_GUID \ + EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \ + 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0) + As stated above, EBBR systems must not provide both ACPI and Devicetree tables at the same time. Systems that support both interfaces must provide a configuration