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- 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.
- stdout-path property
- --------------------
- Device trees may specify the device to be used for boot console output
- with a stdout-path property under /chosen, as described in ePAPR, 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)
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