topic Re: DTS files ... in i.MX Processors

DTS files ...

fabio_poiatti — Mon, 29 Jul 2019 11:23:57 GMT

It is not clear for me the structure of the DTS file ... where can I find them ... how to modify ... etc.

I'm using the EVK for IMX6ULL using this local.conf file

MACHINE ??= 'imx6ull14x14evk'

DISTRO ?= 'fsl-imx-x11'

DISTRO_FEATURES_append = "sysvinit "

VIRTUAL-RUNTIME_init_manager = "sysvinit"

PACKAGE_CLASSES ?= "package_rpm"

EXTRA_IMAGE_FEATURES ?= "debug-tweaks tools-debug eclipse-debug package-management"

USER_CLASSES ?= "buildstats image-mklibs image-prelink"

PATCHRESOLVE = "noop"

BB_DISKMON_DIRS ??= "\

STOPTASKS,${TMPDIR},1G,100K \

STOPTASKS,${DL_DIR},1G,100K \

STOPTASKS,${SSTATE_DIR},1G,100K \

STOPTASKS,/tmp,100M,100K \

ABORT,${TMPDIR},100M,1K \

ABORT,${DL_DIR},100M,1K \

ABORT,${SSTATE_DIR},100M,1K \

ABORT,/tmp,10M,1K"

PACKAGECONFIG_append_pn-qemu-native = " sdl"

PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"

CONF_VERSION = "1"

DL_DIR ?= "${BSPDIR}/downloads/"

ACCEPT_FSL_EULA = "1"

IMAGE_INSTALL_append=" imx-test"

IMAGE_INSTALL_append+=" openssh"

IMAGE_INSTALL_append+=" tcf-agent"

IMAGE_INSTALL_append+=" openssh-sftp-server"

IMAGE_INSTALL_append+=" ppp"

IMAGE_INSTALL_append+=" cronie"

IMAGE_INSTALL_append+=" vsftpd"

PACKAGE_EXCLUDE += " packagegroup-core-ssh-dropbear"

with bitbake core-image-base

thanks

Re: DTS files ...

gusarambula — Tue, 30 Jul 2019 16:28:45 GMT

Hello Fabio Mario Poiatti,

There is some information on the Kernel.org site regarding the usage of the Device Tree. There is also more information and examples on the web and on this Communities.

https://www.kernel.org/doc/Documentation/devicetree/usage-model.txt

Here are a couple of Documents that may be of help:

https://community.nxp.com/docs/DOC-104818

https://community.nxp.com/docs/DOC-329664

If your design will be based on an existing board it’s a good idea to start from the device tree of the existing board and customize for your hardware. You can find the device trees available on the BSP on the following path:

/<BSP_DIR>/<BUILD_DIR>/tmp/work/<MACHINE>-poky-linux-gnueabi/linux-imx/3.14.28-r0/git/arch/arm/boot/dts/

I hope this helps!

Regards,

Re: DTS files ...

fabio_poiatti — Thu, 01 Aug 2019 09:04:50 GMT

Thanks

I'm starting to study ...

Now I'm working on EVK waiting for our custom hardware so I think I will have to possibility to make some modification on DTS ...

Re: DTS files ...

gusarambula — Thu, 01 Aug 2019 16:26:12 GMT

Hello Fabio Mario Poiatti,

I would also recommend looking for the i.MX BSP Porting Guide available as part of the BSP Release documentation as it may be useful when customizing for your hardware.

Regards.

Re: DTS files ...

fabio_poiatti — Thu, 08 Aug 2019 11:45:51 GMT

thanks,

but changing the dts file ... how can I have the modification in the bsp to deploy?

with bitbake linux-imx it seems nothing changed ... and also with bitbake core-image-base

with bitbake linux-imx -c cleansstate the dts files comes to generate again in the next bitbake command

Re: DTS files ...

gusarambula — Thu, 22 Aug 2019 17:49:11 GMT

Hello Fabio Mario Poiatti,

Since Yocto is not intended as a development environment it does not have incremental build options and it does not rebuild what was already built. It also may fetch the original configuration or sources so changes may not be reflected on the binaries.

You may compile the modified device tree outside of the Yocto environment with the toolchain and using the command: make ARCH=arm dtbs (this on the directory where the kernel sources are). There is an example of the following document where a new device tree is created outside of Yocto.

https://community.nxp.com/docs/DOC-331906

If you already have your device tree changes and want to integrate to Yocto it would be ideal if you could create a new layer that either adds your configuration files or appends the BSP original files as to reflect your changes. There is some documentation on how to do this on the Yocto Project page but as far as I’m aware there is not a straightforward guide on how to accomplish it.

My apologies for the inconvenience. I hope this helps!

Regards,

Re: DTS files ...

fabio_poiatti — Fri, 23 Aug 2019 07:22:04 GMT

Thanks,

it is my fault because I'm not so smart about all the Yocto process ... layer ... BSP etc.

But I will try to follow your second suggestion because I think it's easier to make some modification on IMX6ULL EVK DTS file to reflect our own hardware and then integrate the new configuration.

I'm looking for some docs or examples about ...

Many thanks

Re: DTS files ...

gusarambula — Mon, 02 Sep 2019 19:47:59 GMT

Hello Fabio Mario Poiatti,

Yocto looks simple from the outside but the inner workings may become very complex! We have all struggled and it can get overwhelming at times!

I just mentioned a couple of documents in another post that may help. There is a BSP Porting Guide available as part of NXP BSPs documentation which may be of help. It’s more than ten pages long but it does not provide a step by step instruction either so hopefully it may help at least to guide you through the porting process.

https://www.nxp.com/docs/en/user-guide/i.MX_BSP_Porting_Guide_Linux.pdf

There is also a BSP Developer’s Guide from the Yocto Project:

https://www.yoctoproject.org/docs/2.4/bsp-guide/bsp-guide.html

(Make sure that the version corresponds to your Poky version, this link is for Rocko, changes are usually small, but they sometimes are present)

I hope this helps!

Regards,