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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:54 EST.

1	What:		/sys/firmware/devicetree/*
2	Date:		November 2013
3	Contact:	Grant Likely <grant.likely@arm.com>, devicetree@vger.kernel.org
4	Description:
5			When using OpenFirmware or a Flattened Device Tree to enumerate
6			hardware, the device tree structure will be exposed in this
7			directory.
9			It is possible for multiple device-tree directories to exist.
10			Some device drivers use a separate detached device tree which
11			have no attachment to the system tree and will appear in a
12			different subdirectory under /sys/firmware/devicetree.
14			Userspace must not use the /sys/firmware/devicetree/base
15			path directly, but instead should follow /proc/device-tree
16			symlink. It is possible that the absolute path will change
17			in the future, but the symlink is the stable ABI.
19			The /proc/device-tree symlink replaces the devicetree /proc
20			filesystem support, and has largely the same semantics and
21			should be compatible with existing userspace.
23			The contents of /sys/firmware/devicetree/ is a
24			hierarchy of directories, one per device tree node. The
25			directory name is the resolved path component name (node
26			name plus address). Properties are represented as files
27			in the directory. The contents of each file is the exact
28			binary data from the device tree.
30	What:		/sys/firmware/fdt
31	Date:		February 2015
32	KernelVersion:	3.19
33	Contact:	Frank Rowand <frowand.list@gmail.com>, devicetree@vger.kernel.org
34	Description:
35			Exports the FDT blob that was passed to the kernel by
36			the bootloader. This allows userland applications such
37			as kexec to access the raw binary. This blob is also
38			useful when debugging since it contains any changes
39			made to the blob by the bootloader.
41			The fact that this node does not reside under
42			/sys/firmware/device-tree is deliberate: FDT is also used
43			on arm64 UEFI/ACPI systems to communicate just the UEFI
44			and ACPI entry points, but the FDT is never unflattened
45			and used to configure the system.
47			A CRC32 checksum is calculated over the entire FDT
48			blob, and verified at late_initcall time. The sysfs
49			entry is instantiated only if the checksum is valid,
50			i.e., if the FDT blob has not been modified in the mean
51			time. Otherwise, a warning is printed.
52	Users:		kexec, debugging
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