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+COREBOOT firmware information
+
+The device tree node to communicate the location of coreboot's memory-resident
+bookkeeping structures to the kernel. Since coreboot itself cannot boot a
+device-tree-based kernel (yet), this node needs to be inserted by a
+second-stage bootloader (a coreboot "payload").
+
+Required properties:
+ - compatible: Should be "coreboot"
+ - reg: Address and length of the following two memory regions, in order:
+ 1.) The coreboot table. This is a list of variable-sized descriptors
+ that contain various compile- and run-time generated firmware
+ parameters. It is identified by the magic string "LBIO" in its first
+ four bytes. See coreboot's src/include/boot/coreboot_tables.h for
+ details.
+ 2.) The CBMEM area. This is a downward-growing memory region used by
+ coreboot to dynamically allocate data structures that remain resident.
+ It may or may not include the coreboot table as one of its members. It
+ is identified by a root node descriptor with the magic number
+ 0xc0389479 that resides in the topmost 8 bytes of the area. See
+ coreboot's src/lib/dynamic_cbmem.c for details.
+
+Example:
+ firmware {
+ ranges;
+
+ coreboot {
+ compatible = "coreboot";
+ reg = <0xfdfea000 0x264>,
+ <0xfdfea000 0x16000>;
+ }
+ };
This patch adds documentation describing a device tree binding for the coreboot firmware. It is meant to be dynamically added during boot and contains address definitions for the coreboot table (a list of variable-sized descriptors providing information about various compile- and run-time generated firmware parameters) and the CBMEM area (the structure containing most run-time resident memory regions set up by coreboot). These definitions allow kernel drivers to easily access data contained in and pointed to by these regions (such as coreboot's in-memory log). (An example implementation can be seen at http://crosreview.com/203371, which will be submitted at a later point.) Change-Id: I97609d461d306f85851e5efc26c675ca1e2d7e9d Signed-off-by: Julius Werner <jwerner@chromium.org> --- .../devicetree/bindings/firmware/coreboot.txt | 32 ++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Documentation/devicetree/bindings/firmware/coreboot.txt