Re: Linux v5.10 for i.MX8 development


Ankur Tyagi
 

Hello Andrey,

-----Original Message-----
From: Andrey Zhizhikin <andrey.z@...>
Sent: Thursday, 30 September 2021 9:44 PM
To: Ankur Tyagi <Ankur.Tyagi@...>
Cc: meta-freescale@...
Subject: Re: [meta-freescale] Linux v5.10 for i.MX8 development

Hello Ankur,

On Tue, Sep 21, 2021 at 11:43 AM Ankur Tyagi <Ankur.Tyagi@...> wrote:

Hello Andrey,

Hello Ankur,

On Mon, Sep 20, 2021 at 11:30 PM Ankur Tyagi <ankur.tyagi@...> wrote:

Hi,

We are currently using Linux v5.4 for i.MX8 provided by recipe linux-fslc-imx_5.4.bb because as mentioned in recipe as well,
branch "5.4-2.3.x-imx" from repo "linux-fslc" get changes merged from branch "imx_5.4.70_2.3.0" of linux-imx repo
(https://source.codeaurora.org/external/imx/linux-imx/log/?h=imx_5.4.70_2.3.0)

If you're still interested in migrating to the new linux-fslc-imx
kernel, it has been integrated into meta-freescale with this PR:
https://github.com/Freescale/meta-freescale/pull/876

Current recipe now picks up [lf-5.10.52-2.1.0] branch from NXP kernel
repo and has latest stable patch applied.
Thank you so much for your message, indeed interested :-)


Now we are planning to upgrade to Linux v5.10 and here I have few questions:

1. Recipe linux-fslc-lts_5.10.bb doesn't support i.MX8 https://github.com/Freescale/meta-
freescale/blob/325ad529187fb1309b0a889c5196c8df039aeea9/recipes-ke... Neither I can see any merge from NXP linux-imx branch
"lf-5.10.y" into linux-fslc branch "5.10.x+fslc".

When you say that i.MX8 is not supported - to which SoC you're
referring to? Mainline kernel on the [master] branch of this layer
does provide a descent support for all i.MX8M derivatives, but I'm not
entirely sure of the state for i.MX8 family SoC support since I do not
have that HW.
I was referring to COMPATIBLE_MACHINE in linux-fslc-lts_5.10.bb recipe.
It doesn't have mx8 in it (sorry above link is broken)

Can you specify which derivative you're talking about?
We are using i.MX8 Dual core A35

Is there any plan for that merge? If yes, any timeline by which it will happen?
I've looked into updating NXP branch [lf-5.10.y], and it is not
trivial... I'm now short on time to have a full swing of merging the
latest stable update on top of it, but probably would get to this
eventually. If there are any volunteers here that are willing to
undertake this task - this would be really appreciated.

If no, then can I use "imx_v8_defconfig" from linux-imx repo to build kernel using linux-fslc repo?
You can use the `defconfig` file, which is present in the layer to
build [linux-fslc] for i.MX8 machine. It resides in
recipes-kernel/linux/linux-fslc/armv8a/defconfig and is synchronized
with stable kernel release 5.14.

If you however opt-in for [linux-fslc-lts] kernel package, then the
kernel config file would be taken from
recipes-kernel/linux/linux-fslc-lts/armv8a/defconfig, which is also
synchronized with 5.10 from stable.
Thank you for sharing this insight, this is helpful

Are there any specific configuration options you need from
imx_v8_defconfig, which should be present in the defconfig for
mainline recipes?
I haven't done any comparison yet between imx_v8_defconfig from 5.4-2.3.x-imx branch
and mainline defconfig but now I will do that since I know which defconfig is to be used :)

i.MX8 is supported in linux-imx_5.10.bb recipe https://github.com/Freescale/meta-
freescale/blob/325ad529187fb1309b0a889c5196c8df039aeea9/recipes-ke... which is using kernel from branch "lf-5.10.y" provided by
linux-imx repo but this repo is NXP internal and doesn't get updated with stable Linux kernel. It is providing v5.10.35
(https://source.codeaurora.org/external/imx/linux-imx/log/?h=lf-5.10.y)

Correct, but as I've already pointed out - the merge of stable updates
to this kernel base is not trivial... :/

So ideally, just like v5.4 would like to use linux-fslc repo for v5.10 development as well.


Will appreciate any guidance around appropriate repo for v5.10 development for i.MX8
As one of the things to try out: you can switch the BSP flavor to use
"mainline" instead of "nxp", which would take all upstream components
instead of those provided by NXP. Be aware, that if you rely on any
functionality which is present in NXP BSP only (e.g. GPU/VPU) - this
would be unavailable in Mainline BSP.
We don't need GPU/VPU so will try your suggestion to use linux-fslc kernel
and defconfig from linux-fslc-lts/armv8a and see how it goes.

Once again, thanks for your response and suggestions.


thanks
Ankur


--
Regards,
Andrey.
Regards
Ankur
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--
Regards,
Andrey.
Regards
Ankur

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