Compile a module in the host (T2080RDB)

[manoloruiz]

Hi,

I am try to compile a module in my t2080RDB working with the SDK 1.8 that is given by Freescale. However, I cannot succeed.

What do I want? I want to compile a module in the host.
What is the problem? I do not have the kernel headers in my host (T2080RDB) after a bitbake fsl-image-full and turn the T2080 on with the result files.

How can I get the kernel headers for my T2080RDB?

If this is not possible, how can I compile only a module  (not a full version of the system) in the yocto enviroment?

Thanks a lot.

[bpe]

If you want to build an off-kernel module with Yocto, you need to

create a separate package that depends on the kernel. The 'cryptodev'

package is as an example.

External module build procedures are described in details in

Documentation/kbuild/modules.txt. The path is from the top kernel source directory.

Some additional information can be found here:

http://www.tldp.org/LDP/lkmpg/2.6/html/x181.html

Have a great day,
Platon

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[manoloruiz]

Thank for your answer. However, it does not work. When we build the de system with the comand  bitbake fsl-image-full, we cannot find the next directory:

/lib/modules/$(shell uname -r)/build

In this directory should be the kernel headers. But it is not. Where can I get the headers? Are there alternative procedure to build a module?

[bpe]

Use the commands specified in Section 2.1 of the first document, modules.txt. You need to build the kernel first:

Customizing Linux Kernel

[manoloruiz]

Thank for your answer. This are the steps I have followed:

1. I have reinstall sdk 1.8 freescale in my PC.

2. I  typed  ./poky/scripts/host-prepare.sh

3. I typed source ./poky/fsl-setup-poky -m t2080rdb

4. I typed . /home/user/QorIQ-SDK-V1.8-20150619-yocto/build_t2080rdb_release/SOURCE_THIS

5. I typed bitbake -c menuconfig virtual/kernel and safe ".conf"

6. I typed bitbake -c compile -f virtual/kernel

7. I typed bitbake virtual/kernel

With those steps I haved the  compiled kernel (no headers) in ../build_t2080rdb_release/tmp/deploy/images/t2080rdb/

Afterward, I came back to /home/user/build_t2080rdb_release.

8. I typed bitbake fsl-image-full

After a while, I get in the next directory : /home/user/QorIQ-SDK-V1.8-20150619-yocto/build_t2080rdb_release/tmp/deploy/images/t2080rdb/. I can find a root file system called "fsl-image-full-t2080rdb-20150907191330.rootfs.tar.gz". This is the root file system which is going to be in the t2080rdb.

After follow this steps, I cannot find the following directories:  /usr/src/header<version>/ or /lib/modules/$(shell uname -r)/build

Without this directory(usr/src/header<version> in ubuntu) or the soft link (/lib/modules/$(shell uname -r)/build) is not possible to compile a module in the target ( in the T2080rdb). What am I doing wrong? I want to compile in the target. If it is not possible, I would like to compile in the host, but I don't know how to do it.

I am using the next Makefile which works in ubuntu for example:

ifneq ($(KERNELRELEASE),)

# kbuild part of makefile

obj-m  :=new14.o

else

# normal makefile

  KDIR ?= /lib/modules/`uname -r`/build

default:

  $(MAKE) -C $(KDIR) M=$$PWD

endif

Thanks.

[manoloruiz]

I have kept on looking for solution. I haven't found yet. In the new realease of yocto (after daisy that is working in freescale sdk 1.8), there is a method:

Yocto Project Linux Kernel Development Manual

2.5.1. Building Out-of-Tree Modules on the Target:

# cd /usr/src/kernel
# make scripts

Because all SDK image recipes include dev-pkgs, the kernel-dev packages will be installed as part of the SDK image and thekernel-devsrc packages will be installed as part of applicable SDK images. The SDK uses the scripts when building out-of-tree modules. Once you have switched to that directory and created the scripts, you should be able to build your out-of-tree modules on the target.

However, I cannot find in my sdk image that works in the target (T2080rdb) the directory /usr/src/kernel.  What can I do?

thanks a lot.

[bpe · Accepted solution]

Please read carefully the recommended documentation, it will help you

to understand what you are doing. The suggestions given earlier in

this thread are for building a module on the _host_. This document

specifies clearly where to locate kernel sources after unpacking:

http://www.freescale.com/infocenter/topic/QORIQSDK/3069694.html

They are _not_ automatically transferred to the target root filesystem.

Your makefile is not valid for cross-compiling a module because it

sets a wrong path to the kernel source directory. Again, study the

modules.txt as recommended, and specify the unpacked kernel location

after -C option to make.

For building on the target, transfer the kernel sources to the

target by hand and follow the same procedure.

Have a great day,
Platon

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[c2357]

I am having the same problem, but that article no longer seems to exist.  Could you update this answer?