Re: [PATCH 3/3] ARM: i.MX: xload-gpmi-nand: apply errata 007117

From: Sascha Hauer <sha@pengutronix.de>
To: Andrej Picej <andrej.picej@norik.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 3/3] ARM: i.MX: xload-gpmi-nand: apply errata 007117
Date: Mon, 25 Jan 2021 09:57:17 +0100	[thread overview]
Message-ID: <20210125085717.GC31738@pengutronix.de> (raw)
In-Reply-To: <65415553-750c-810d-7902-b1052d764bec@norik.com>

On Fri, Jan 22, 2021 at 10:47:09AM +0100, Andrej Picej wrote:
> 
> 
> On 22. 01. 21 09:12, Sascha Hauer wrote:
> > On Thu, Jan 21, 2021 at 01:23:16PM +0100, Andrej Picej wrote:
> > > Hi Sascha,
> > > 
> > > yes, unfortunately we have. We applied this just because we experienced
> > > hangs in device booting tests. After this patch the NAND booting problems
> > > went away. The booting failed during DMA page reading.
> > > I just tested this again and after excluding the changes in this patch the
> > > device fails at executing DMA commands. The boot fails in approximately one
> > > out of 10 boots.
> > 
> > Where exactly did it hang? In the xloader or later in the real barebox
> > driver?
> > You probably mean that it hangs in the xloader. Sorry to ask, but I'm
> > still trying to understand. That would mean the ROM leaves the GPMI in
> > an unusable state and I really wonder how this can happen.
> > 
> > Sascha
> > 
> 
> Sorry for not being clear enough the first time. You are correct, it hangs
> in xloader.
> 
> Maybe some additional information that may be relevant. When we boot barebox
> without PBL support barebox boots without problem and NAND behaves normal,
> so i guess the ROM sets the GPMI in usable state.
> Just a thought: could it be that the problem is in xloader and we somehow
> repair or reset the GPMI with this errata fix, so it works with xloader?

It could be that the ROM changes parts of the clock tree after having
loaded the image from NAND and before it jumps to the payload. It might
be that we would have the same problem in the real barebox driver if we
wouldn't reconfigure the clocks anyway in the clock driver.

Sascha

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