You can find these files in the BSP Layer at:
meta-bsp_root_name
/conf/machine/*.conf
The machine files bind together all the information
contained elsewhere in the BSP into a format that
the build system can understand.
Each BSP Layer requires at least one machine file.
If the BSP supports multiple machines, multiple
machine configuration files can exist.
These filenames correspond to the values to which
users have set the
MACHINE
variable.
These files define things such as the kernel package
to use
(PREFERRED_PROVIDER
of
virtual/kernel),
the hardware drivers to include in different types
of images, any special software components that are
needed, any bootloader information, and also any
special image format requirements.
This configuration file could also include a hardware "tuning" file that is commonly used to define the package architecture and specify optimization flags, which are carefully chosen to give best performance on a given processor.
Tuning files are found in the
meta/conf/machine/include
directory within the
Source Directory.
For example, many tune-*
files
(e.g. tune-arm1136jf-s.inc
,
tun-1586-nlp.inc
, and so forth)
reside in the
poky/meta/conf/machine/include
directory.
To use an include file, you simply include them in the
machine configuration file.
For example, the Raspberry Pi BSP
raspberrypi3.conf
contains the
following statement:
include conf/machine/include/rpi-base.inc