Re: CAN ISO-TP Availability for Yocto

From: Oliver Hartkopp <socketcan@hartkopp.net>
To: Jin Park <jpark@enphaseenergy.com>
Cc: "linux-can@vger.kernel.org" <linux-can@vger.kernel.org>
Subject: Re: CAN ISO-TP Availability for Yocto
Date: Fri, 4 Dec 2020 09:14:59 +0100	[thread overview]
Message-ID: <f17f5543-192b-b33d-df8b-1ea572b5c6c7@hartkopp.net> (raw)
In-Reply-To: <DM6PR19MB36737423D8AC8E3C53912988B1F20@DM6PR19MB3673.namprd19.prod.outlook.com>

Hello Jin,

On 03.12.20 23:50, Jin Park wrote:

> I tried to build and load module and build image with Yocto frameworks 
> and it showed the error like this.
> 
> ‘can-isotp was skipped: Recipe is blacklisted: Kernel module Needs 
> forward porting to kernel 5.2+’
> 
> Do you know whether CAN ISO-TP supports Yocto project?

the CAN ISO-TP support will be in mainline Linux starting with Linux 
kernel 5.10.

For older kernels you may use the implementation for out-of-tree 
compilation which is located here:
https://github.com/hartkopp/can-isotp (master branch)

There is also a more up-to-date version in the 4.17+ branch which I used 
to prepare the mainline process.

But out-of-tree compilation is probably not to right way to integrate 
iso-tp into Yocto. I would suggest to backport the current mainline code 
to Kernel 5.4 and create a patch for it so that is applied to the kernel 
code before the kernel compilation process.
(Is this already the process in Yocto to have a patch like this which 
lead to the Yocto error message??)

Backporting the 5.10-rc mainline code to 5.4 is really easy as only one 
thing needs to be changed/reverted:
https://github.com/hartkopp/can-isotp/commit/98986fc2f07cb5c7fa73a86d9b4b3ae417d35d79

> I tried to bake module in below condition.
> 
>   * Hardware: VAR-SOM-MX8M-NANO
>   * Yocto version: Dunfell Kernel 5.4.74
> 
> jin@jin-ThinkPad-P51:~/var-fslc-yocto$ bitbake can-isotp
> 
> WARNING: You have included the meta-virtualization layer, but 
> 'virtualization' has not been enabled in your DISTRO_FEATURES. Some 
> bbappend files may not take effect. See the meta-virtualization README 
> for details on enabling virtualization support.
> 
> Loading cache: 100% 
> |#########################################################################################################################################################################| 
> Time: 0:00:00
> 
> Loaded 3848 entries from dependency cache.
> 
> ERROR: Nothing PROVIDES 'can-isotp'
> 
> can-isotp was skipped: Recipe is blacklisted: Kernel module Needs 
> forward porting to kernel 5.2+

I'm not familiar with Yocto. But when they created a kernel patch 
including code/include/Kconfig/Makefile (as suggested above) it should 
be easy to backport the mainline code as base for a 5.4 kernel patch.

Please let me know if you have problems creating such a 5.4 kernel patch.

Regards,
Oliver