xref: /openbmc/u-boot/dts/Kconfig (revision 729c2db7)
1#
2# Device Tree Control
3#
4
5config SUPPORT_OF_CONTROL
6	bool
7
8menu "Device Tree Control"
9	depends on SUPPORT_OF_CONTROL
10
11config OF_CONTROL
12	bool "Run-time configuration via Device Tree"
13	help
14	  This feature provides for run-time configuration of U-Boot
15	  via a flattened device tree.
16
17config SPL_OF_CONTROL
18	bool "Enable run-time configuration via Device Tree in SPL"
19	depends on SPL && OF_CONTROL
20	help
21	  Some boards use device tree in U-Boot but only have 4KB of SRAM
22	  which is not enough to support device tree. Enable this option to
23	  allow such boards to be supported by U-Boot SPL.
24
25choice
26	prompt "Provider of DTB for DT control"
27	depends on OF_CONTROL
28
29config OF_SEPARATE
30	bool "Separate DTB for DT control"
31	depends on !SANDBOX
32	help
33	  If this option is enabled, the device tree will be built and
34	  placed as a separate u-boot.dtb file alongside the U-Boot image.
35
36config OF_EMBED
37	bool "Embedded DTB for DT control"
38	help
39	  If this option is enabled, the device tree will be picked up and
40	  built into the U-Boot image. This is suitable for local debugging
41	  and development only and is not recommended for production devices.
42	  Boards in the mainline U-Boot tree should not use it.
43
44config OF_HOSTFILE
45	bool "Host filed DTB for DT control"
46	depends on SANDBOX
47	help
48	  If this option is enabled, DTB will be read from a file on startup.
49	  This is only useful for Sandbox.  Use the -d flag to U-Boot to
50	  specify the file to read.
51
52endchoice
53
54config DEFAULT_DEVICE_TREE
55	string "Default Device Tree for DT control"
56	depends on OF_CONTROL
57	help
58	  This option specifies the default Device Tree used for DT control.
59	  It can be overridden from the command line:
60	  $ make DEVICE_TREE=<device-tree-name>
61
62config OF_LIST
63	string "List of device tree files to include for DT control"
64	depends on SPL_LOAD_FIT
65	default DEFAULT_DEVICE_TREE
66	help
67	  This option specifies a list of device tree files to use for DT
68	  control. These will be packaged into a FIT. At run-time, SPL will
69	  select the correct DT to use by examining the hardware (e.g.
70	  reading a board ID value). This is a list of device tree files
71	  (without the directory or .dtb suffix) separated by <space>.
72
73config OF_SPL_REMOVE_PROPS
74	string "List of device tree properties to drop for SPL"
75	depends on SPL_OF_CONTROL
76	default "interrupt-parent" if SPL_PINCTRL_FULL && SPL_CLK
77	default "clocks clock-names interrupt-parent" if SPL_PINCTRL_FULL
78	default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK
79	default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent"
80	help
81	  Since SPL normally runs in a reduced memory space, the device tree
82	  is cut down to only what is needed to load and start U-Boot. Only
83	  nodes marked with the property "u-boot,dm-pre-reloc" will be
84	  included. In addition, some properties are not used by U-Boot and
85	  can be discarded. This option defines the list of properties to
86	  discard.
87
88config SPL_OF_PLATDATA
89	bool "Generate platform data for use in SPL"
90	depends on SPL_OF_CONTROL
91	help
92	  For very constrained SPL environments the overhead of decoding
93	  device tree nodes and converting their contents into platform data
94	  is too large. This overhead includes libfdt code as well as the
95	  device tree contents itself. The latter is fairly compact, but the
96	  former can add 3KB or more to a Thumb 2 Image.
97
98	  This option enables generation of platform data from the device
99	  tree as C code. This code creates devices using U_BOOT_DEVICE()
100	  declarations. The benefit is that it allows driver code to access
101	  the platform data directly in C structures, avoidin the libfdt
102	  overhead.
103
104	  This option works by generating C structure declarations for each
105	  compatible string, then adding platform data and U_BOOT_DEVICE
106	  declarations for each node. See README.platdata for more
107	  information.
108
109endmenu
110