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Diffstat (limited to 'Documentation/devicetree/bindings/chosen.txt')
| -rw-r--r-- | Documentation/devicetree/bindings/chosen.txt | 137 |
1 files changed, 0 insertions, 137 deletions
diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt deleted file mode 100644 index 1cc3aa10dcb1..000000000000 --- a/Documentation/devicetree/bindings/chosen.txt +++ /dev/null @@ -1,137 +0,0 @@ -The chosen node ---------------- - -The chosen node does not represent a real device, but serves as a place -for passing data between firmware and the operating system, like boot -arguments. Data in the chosen node does not represent the hardware. - -The following properties are recognized: - - -kaslr-seed ------------ - -This property is used when booting with CONFIG_RANDOMIZE_BASE as the -entropy used to randomize the kernel image base address location. Since -it is used directly, this value is intended only for KASLR, and should -not be used for other purposes (as it may leak information about KASLR -offsets). It is parsed as a u64 value, e.g. - -/ { - chosen { - kaslr-seed = <0xfeedbeef 0xc0def00d>; - }; -}; - -Note that if this property is set from UEFI (or a bootloader in EFI -mode) when EFI_RNG_PROTOCOL is supported, it will be overwritten by -the Linux EFI stub (which will populate the property itself, using -EFI_RNG_PROTOCOL). - -stdout-path ------------ - -Device trees may specify the device to be used for boot console output -with a stdout-path property under /chosen, as described in the Devicetree -Specification, e.g. - -/ { - chosen { - stdout-path = "/serial@f00:115200"; - }; - - serial@f00 { - compatible = "vendor,some-uart"; - reg = <0xf00 0x10>; - }; -}; - -If the character ":" is present in the value, this terminates the path. -The meaning of any characters following the ":" is device-specific, and -must be specified in the relevant binding documentation. - -For UART devices, the preferred binding is a string in the form: - - <baud>{<parity>{<bits>{<flow>}}} - -where - - baud - baud rate in decimal - parity - 'n' (none), 'o', (odd) or 'e' (even) - bits - number of data bits - flow - 'r' (rts) - -For example: 115200n8r - -Implementation note: Linux will look for the property "linux,stdout-path" or -on PowerPC "stdout" if "stdout-path" is not found. However, the -"linux,stdout-path" and "stdout" properties are deprecated. New platforms -should only use the "stdout-path" property. - -linux,booted-from-kexec ------------------------ - -This property is set (currently only on PowerPC, and only needed on -book3e) by some versions of kexec-tools to tell the new kernel that it -is being booted by kexec, as the booting environment may differ (e.g. -a different secondary CPU release mechanism) - -linux,usable-memory-range -------------------------- - -This property holds a base address and size, describing a limited region in -which memory may be considered available for use by the kernel. Memory outside -of this range is not available for use. - -This property describes a limitation: memory within this range is only -valid when also described through another mechanism that the kernel -would otherwise use to determine available memory (e.g. memory nodes -or the EFI memory map). Valid memory may be sparse within the range. -e.g. - -/ { - chosen { - linux,usable-memory-range = <0x9 0xf0000000 0x0 0x10000000>; - }; -}; - -The main usage is for crash dump kernel to identify its own usable -memory and exclude, at its boot time, any other memory areas that are -part of the panicked kernel's memory. - -While this property does not represent a real hardware, the address -and the size are expressed in #address-cells and #size-cells, -respectively, of the root node. - -linux,elfcorehdr ----------------- - -This property holds the memory range, the address and the size, of the elf -core header which mainly describes the panicked kernel's memory layout as -PT_LOAD segments of elf format. -e.g. - -/ { - chosen { - linux,elfcorehdr = <0x9 0xfffff000 0x0 0x800>; - }; -}; - -While this property does not represent a real hardware, the address -and the size are expressed in #address-cells and #size-cells, -respectively, of the root node. - -linux,initrd-start and linux,initrd-end ---------------------------------------- - -These properties hold the physical start and end address of an initrd that's -loaded by the bootloader. Note that linux,initrd-start is inclusive, but -linux,initrd-end is exclusive. -e.g. - -/ { - chosen { - linux,initrd-start = <0x82000000>; - linux,initrd-end = <0x82800000>; - }; -}; |