On 2019-05-07 08:41, Gabriele Zampieri wrote:

Hi all,

Bas' defconfig trick (do_set_custom_defconfig) is already implemented by Yocto itself: just add a file called defconfig to SRC_URI and the system will apply it for you (you can read kernel_do_configure in kernel.bbclass) . For more information check https://www.yoctoproject.org/docs/latest/mega-manual/mega-manual.html#changing-the-configuration


Yes, that is the better solution. Not sure why I did not use it. I created the "do_set_custom_defconfig" years ago. Maybe to be able in the future to select one of different defconfigs based upon a local.conf setting. There can only be one in the kernel bbclass. I would prefer to be able to add multiple files ending on e.g. _defconfig and be able to set a variable to select the one to use.

Maybe we can define something similar for the device tree file source file in the bbclass. It would obviously only be valid for architectures supporting device trees.

how did you do the defconfig usually?

The link I put above asks this question too.

# The first patch simply appends my custom DTS to the list of DTD files in the Makefile

and

I usually don't need to make large modifications to the kernel source, so I don't need to clone the kernel, but use the default kernel for the
SoC with some patches.

How do you generate that patches?

I know that the kernel repo is huge, but having a local kernel tree can be very useful and allows you to do all the patchworks easily. It also speeds up the test if you are planning to upgrade some part of it.


I use custom BSP development environment that contains a small build environment for building the device tree from source, u-boot development, kernel tree (shallow) clone, extended mfgtools ramdisk with some utilities and a customized version of mfgtools that loads the before-mentioned parts in RAM and starts them. This allows me to do very quick cycles.

The kernel patches are created using git against a (shallow) clone of the kernel I want to use. Mostly it is nothing more than a few small fixes. U-boot is a full clone as I setup a new board definition for the custom board (mostly derived from an existing dev board, both hw and sw wise).

-- Bas.

Best regards,

Gabriele

Il giorno mar 7 mag 2019 alle ore 02:14 JH <jupiter....@gmail.com> ha scritto:

Hi Bas and Gabriele,

Thank you so much for you advice.

My usual way of doing it is as follows:

I usually don't need to make large modifications to the kernel source, so I don't need to clone the kernel, but use the default kernel for the
SoC with some patches.

So do I.

I use a platform support layer and add a .bbappend file for the (arm)
kernel to add a custom dts and .config files, together with some small
patches:

*** File meta-<platform>/recipes-kernel/linux/linux-<version>_%.bbappend:

THISAPPENDFILESDIR := "${THISDIR}/files"
FILESEXTRAPATHS_prepend := "${THISDIR}/files:"

require linux-set-custom-defconfig.inc
require linux-add-custom-dts.inc

# The first patch simply appends my custom DTS to the list of DTD files
in the Makefile
SRC_URI += \
"file://add-custom-dts.patch \
file://some_other.patch \
file://another_driver_patch.patch \
"

*** File meta-<platform>/recipes-kernel/linux/linux-add-custom-dts.inc

do_add_platform_dts() {
cp -f "${THISAPPENDFILESDIR}/custom.dts" \
"${WORKDIR}/git/arch/arm/boot/dts"
}

That is exactly I am looking for the proper location of the dts files,
thank you so much.

addtask add_platform_dts before do_preconfigure after do_patch

*** File
meta-<platform>/recipes-kernel/linux/linux-set-custom-defconfig.inc

do_set_custom_defconfig() {
cp -f "${THISAPPENDFILESDIR}/defconfig" "${WORKDIR}/defconfig"
}

addtask set_custom_defconfig before do_preconfigure after do_patch

Good advice, I missed that one, how did you do the defconfig usually?
Compile it in kernel source like using following command?

make ARCH=arm imx_v6_v7_defconfig

It is maybe a bit complex, but it saves cloning the kernel for the sake
of just adding a single DTS with defconfig and a few patches.

That is procedure I was looking for.

Hope this helps,

Great helps, thank you so much.

- jupiter

Bas.

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