blob: 965a374071ab896fe58fdaadcd25a2feba93d7c3 [file] [log] [blame]
.. SPDX-License-Identifier: GPL-2.0
DeviceTree Booting
There is one single 32bit entry point to the kernel at code32_start,
the decompressor (the real mode entry point goes to the same 32bit
entry point once it switched into protected mode). That entry point
supports one calling convention which is documented in
The physical pointer to the device-tree block is passed via setup_data
which requires at least boot protocol 2.09.
The type filed is defined as
#define SETUP_DTB 2
This device-tree is used as an extension to the "boot page". As such it
does not parse / consider data which is already covered by the boot
page. This includes memory size, reserved ranges, command line arguments
or initrd address. It simply holds information which can not be retrieved
otherwise like interrupt routing or a list of devices behind an I2C bus.