xref: /openbmc/u-boot/dts/Kconfig (revision 66928afb6b55647a446560d32427a032e674301f)
1 #
2 # Device Tree Control
3 #
4 
5 config SUPPORT_OF_CONTROL
6 	bool
7 
8 menu "Device Tree Control"
9 	depends on SUPPORT_OF_CONTROL
10 
11 config 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 
17 config OF_BOARD_FIXUP
18 	bool "Board-specific manipulation of Device Tree"
19 	help
20 	  In certain circumstances it is necessary to be able to modify
21 	  U-Boot's device tree (e.g. to delete device from it). This option
22 	  make the Device Tree writeable and provides a board-specific
23 	  "board_fix_fdt" callback (called during pre-relocation time), which
24 	  enables the board initialization to modifiy the Device Tree. The
25 	  modified copy is subsequently used by U-Boot after relocation.
26 
27 config SPL_OF_CONTROL
28 	bool "Enable run-time configuration via Device Tree in SPL"
29 	depends on SPL && OF_CONTROL
30 	help
31 	  Some boards use device tree in U-Boot but only have 4KB of SRAM
32 	  which is not enough to support device tree. Enable this option to
33 	  allow such boards to be supported by U-Boot SPL.
34 
35 choice
36 	prompt "Provider of DTB for DT control"
37 	depends on OF_CONTROL
38 
39 config OF_SEPARATE
40 	bool "Separate DTB for DT control"
41 	depends on !SANDBOX
42 	help
43 	  If this option is enabled, the device tree will be built and
44 	  placed as a separate u-boot.dtb file alongside the U-Boot image.
45 
46 config OF_EMBED
47 	bool "Embedded DTB for DT control"
48 	help
49 	  If this option is enabled, the device tree will be picked up and
50 	  built into the U-Boot image. This is suitable for local debugging
51 	  and development only and is not recommended for production devices.
52 	  Boards in the mainline U-Boot tree should not use it.
53 
54 config OF_BOARD
55 	bool "Provided by the board at runtime"
56 	depends on !SANDBOX
57 	help
58 	  If this option is enabled, the device tree will be provided by
59 	  the board at runtime if the board supports it, instead of being
60 	  bundled with the image.
61 
62 config OF_HOSTFILE
63 	bool "Host filed DTB for DT control"
64 	depends on SANDBOX
65 	help
66 	  If this option is enabled, DTB will be read from a file on startup.
67 	  This is only useful for Sandbox.  Use the -d flag to U-Boot to
68 	  specify the file to read.
69 
70 endchoice
71 
72 config DEFAULT_DEVICE_TREE
73 	string "Default Device Tree for DT control"
74 	depends on OF_CONTROL
75 	help
76 	  This option specifies the default Device Tree used for DT control.
77 	  It can be overridden from the command line:
78 	  $ make DEVICE_TREE=<device-tree-name>
79 
80 config OF_LIST
81 	string "List of device tree files to include for DT control"
82 	depends on SPL_LOAD_FIT
83 	default DEFAULT_DEVICE_TREE
84 	help
85 	  This option specifies a list of device tree files to use for DT
86 	  control. These will be packaged into a FIT. At run-time, SPL will
87 	  select the correct DT to use by examining the hardware (e.g.
88 	  reading a board ID value). This is a list of device tree files
89 	  (without the directory or .dtb suffix) separated by <space>.
90 
91 config OF_SPL_REMOVE_PROPS
92 	string "List of device tree properties to drop for SPL"
93 	depends on SPL_OF_CONTROL
94 	default "interrupt-parent" if SPL_PINCTRL && SPL_CLK
95 	default "clocks clock-names interrupt-parent" if SPL_PINCTRL
96 	default "pinctrl-0 pinctrl-names interrupt-parent" if SPL_CLK
97 	default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent"
98 	help
99 	  Since SPL normally runs in a reduced memory space, the device tree
100 	  is cut down to only what is needed to load and start U-Boot. Only
101 	  nodes marked with the property "u-boot,dm-pre-reloc" will be
102 	  included. In addition, some properties are not used by U-Boot and
103 	  can be discarded. This option defines the list of properties to
104 	  discard.
105 
106 config SPL_OF_PLATDATA
107 	bool "Generate platform data for use in SPL"
108 	depends on SPL_OF_CONTROL
109 	help
110 	  For very constrained SPL environments the overhead of decoding
111 	  device tree nodes and converting their contents into platform data
112 	  is too large. This overhead includes libfdt code as well as the
113 	  device tree contents itself. The latter is fairly compact, but the
114 	  former can add 3KB or more to a Thumb 2 Image.
115 
116 	  This option enables generation of platform data from the device
117 	  tree as C code. This code creates devices using U_BOOT_DEVICE()
118 	  declarations. The benefit is that it allows driver code to access
119 	  the platform data directly in C structures, avoidin the libfdt
120 	  overhead.
121 
122 	  This option works by generating C structure declarations for each
123 	  compatible string, then adding platform data and U_BOOT_DEVICE
124 	  declarations for each node. See README.platdata for more
125 	  information.
126 
127 endmenu
128