[U-Boot] Booting imx_4.14.98_2.0.0_ga on i.MX8QM MEK Board

[Marcel Ziswiler]

Hi Peng

On Thu, 2019-05-02 at 10:06 +0000, Peng Fan wrote:
> > -----Original Message-----
> > From: Marcel Ziswiler [mailto:marcel.ziswiler at toradex.com]
> > Sent: 2019年5月2日 17:47
> > To: Peng Fan <peng.fan at nxp.com>; Fabio Estevam
> > <fabio.estevam at nxp.com>; sbabic at denx.de
> > Cc: u-boot at lists.denx.de; dl-uboot-imx <uboot-imx at nxp.com>
> > Subject: Re: Booting imx_4.14.98_2.0.0_ga on i.MX8QM MEK Board
> > 
> > Hi Peng
> > 
> > On Thu, 2019-05-02 at 03:57 +0000, Peng Fan wrote:
> > > Hi Marcel,
> > > 
> > > > Subject: Booting imx_4.14.98_2.0.0_ga on i.MX8QM MEK Board
> > > > 
> > > > Hi Peng, Stefano and Fabio
> > > > 
> > > > We are currently trying to boot the Linux kernel from NXP's
> > > > downstream Linux BSP 4.14.98_2.0.0_ga with mainline U-Boot.
> > > > However,
> > > > that currently seems to crash as follows:
> > > > 
> > > > ...
> > > > 
> > > > Does any of you know what exactly could be going on?
> > > 
> > > SMMU is not powered up, so smmu driver probe triggers abort when
> > > accessing SMMU registers. Need power up SC_R_SMMU.
> > 
> > I see, this is actually done in downstream U-Boot:
> > 
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsource
> > .codeaurora.org%2Fexternal%2Fimx%2Fuboot-imx%2Fcommit%2F%3Fh%3Di
> > mx_v2018.03_4.14.98_2.0.0_ga%26id%3D45308e7da90f342c2de7fbec1f8c5
> > b8bd3f1b8e5&data=02%7C01%7Cpeng.fan%40nxp.com%7C4ba5e68e20
> > 6341af29df08d6cee328ab%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%
> > 7C0%7C636923872368096043&sdata=tj%2B9CGkzJhsidj8HvniZ7%2B%2
> > FFK%2BbbE4GrP%2FJ5aeu5NiE%3D&reserved=0
> > 
> > Wondering how that is supposed to work with mainline U-Boot at the
> > end.

Any comment/suggestion?

> I think just power up SMMU is fine in mainline U-Boot.
> 
> > > > BTW: The exact same crash is observed on Apalis iMX8 as well,
> > > > while
> > > > both the i.MX8QXP MEK as well as Colibri iMX8QXP boot that same
> > > > downstream Linux kernel just fine. Must be something i.MX
> > > > 8QuadMax
> > > > specific...
> > > 
> > > There is no SMMU on i.MX8QXP.
> > 
> > Funny, at least in downstream U-Boot the same SMMU setup is done
> > (;-p).
> 
> CONFIG_IMX_SMMU is not defined for i.MX8QXP.

I am wondering why exactly you would come to such a conclusion. At
least the following configuration header file still seems to define it:

https://source.codeaurora.org/external/imx/uboot-imx/tree/include/configs/imx8qxp_mek.h?h=imx_v2018.03_4.14.98_2.0.0_ga#n370

> Regards,
> Peng.
> 
> > > Regards,
> > > Peng.
> > 
> > Thanks, Peng!
> > 
> > > > Cheers
> > > > 
> > > > Marcel
> > 
> > Cheers
> > 
> > Marcel

Cheers

Marcel