You can find these files in the BSP Layer at:
meta-<bsp_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.
If the BSP supports multiple machines, multiple machine configuration files
can be present.
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.
Each BSP Layer requires at least one machine file.
However, you can supply more than one file.
For example, in the Crown Bay BSP shown earlier in this section, the
conf/machine
directory contains two configuration files:
crownbay.conf
and crownbay-noemgd.conf
.
The crownbay.conf
file is used for the Crown Bay BSP
that supports the Intel® Embedded
Media and Graphics Driver (Intel®
EMGD), while the crownbay-noemgd
file is used for the
Crown Bay BSP that supports Video Electronics Standards Association (VESA)
graphics only.
This crownbay.conf
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.
Tuning files can also reside in the BSP Layer itself.
For example, the ia32-base.inc
file resides in the
meta-intel
BSP Layer in conf/machine/include
.
To use an include file, you simply include them in the machine configuration file.
For example, the Crown Bay BSP crownbay.conf
has the
following statements:
require conf/machine/include/tune-atom.inc require conf/machine/include/ia32-base.inc