You can find these files in the BSP Layer at:
meta-bsp_root_name
/recipes-kernel/linux/linux*.bbappend meta-bsp_root_name
/recipes-kernel/linux/*.bb
Append files (*.bbappend
) modify
the main kernel recipe being used to build the image.
The *.bb
files would be a
developer-supplied kernel recipe.
This area of the BSP hierarchy can contain both these
types of files, although in practice, it is likely that
you would have one or the other.
For your BSP, you typically want to use an existing Yocto
Project kernel recipe found in the
Source Directory
at meta/recipes-kernel/linux
.
You can append machine-specific changes to the
kernel recipe by using a similarly named append
file, which is located in the BSP Layer for your
target device (e.g. the
meta-
directory).
bsp_root_name
/recipes-kernel/linux
Suppose you are using the
linux-yocto_4.4.bb
recipe to
build the kernel.
In other words, you have selected the kernel in your
bsp_root_name
.conf
file by adding
PREFERRED_PROVIDER
and
PREFERRED_VERSION
statements as follows:
PREFERRED_PROVIDER_virtual/kernel ?= "linux-yocto" PREFERRED_VERSION_linux-yocto ?= "4.4%"
PREFERRED_PROVIDER
statement does not appear in the
bsp_root_name
.conf
file.
You would use the
linux-yocto_4.4.bbappend
file to append specific BSP settings to the kernel,
thus configuring the kernel for your particular BSP.
You can find more information on what your append file should contain in the "Creating the Append File" section in the Yocto Project Linux Kernel Development Manual.
An alternate scenario is when you create your own
kernel recipe for the BSP.
A good example of this is the Raspberry Pi BSP.
If you examine the
recipes-kernel/linux
directory
you see the following:
linux-raspberrypi-dev.bb linux-raspberrypi.inc linux-raspberrypi_4.14.bb linux-raspberrypi_4.9.bb
The directory contains three kernel recipes and a common include file.