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

[Peng Fan]

> -----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.

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.

Regards,
Peng.

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