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From: Sascha Hauer <sha@pengutronix.de>
To: Joacim Zetterling <joaze@westermo.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH v3] Fix problem with imx_ddrc_sdram_size calc
Date: Wed, 17 Nov 2021 08:23:57 +0100	[thread overview]
Message-ID: <20211117072357.GJ6556@pengutronix.de> (raw)
In-Reply-To: <20211115140539.GA118449@wsevst-c0022>

On Mon, Nov 15, 2021 at 03:05:39PM +0100, Joacim Zetterling wrote:
> On Fri, Nov 05, 2021 at 10:39:27AM +0100, Sascha Hauer wrote:
> > Hi Joacim,
> > 
> > On Mon, Nov 01, 2021 at 01:11:09PM +0100, Joacim Zetterling wrote:
> > > There was some issues with the imx_ddrc_sdram_size calculation.
> > > 
> > > If we compare the imx8mn DDR4 evk against the LPDDR4 variant in
> > > code and in the datasheets, we see the following:
> > > 
> > >              DDR4   LPDDR4
> > >   ========================
> > >   Bus width   16      16
> > >   Rank        1       1
> > >   Ranks       1       1
> > >   Banks       4       8
> > >   Banks grps  2       1
> > >   Rows        17      15
> > >   Col         10      10
> > > 
> > > This gives us the following problems:
> > > 
> > > 1. Bus width problem.
> > >    Does not support 16 bit SDRAM bus mode, only 32 bit supported
> > > 
> > > 2. Row size problem.
> > >    Only up to 16 bit row size support.
> > > 
> > > 3. Bank groups support.
> > >    Only support of 1 bank group.
> > > 
> > > 4. Bit count problem.
> > >    The imx_ddrc_count_bits function does not do a correct count.
> > 
> > Could you split this into four patches fixing one problem at a time?
> > I am not sure the problems can be separated from each other entirely,
> > but splitting this up would make it much easier to understand the
> > problems and also their fixes. We'll be glad having smaller patches
> > should we ever have to look at this again.
> > 
> > Sascha
> I agree with You that the problems can not be separated completely.
> But I will try to do my best. Do You prefer a patch set or separately
> patches or a combination of them both?

A patch set would be fine.

Sascha


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      reply	other threads:[~2021-11-17  7:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-01 12:11 Joacim Zetterling
2021-11-05  9:39 ` Sascha Hauer
2021-11-15 14:05   ` Joacim Zetterling
2021-11-17  7:23     ` Sascha Hauer [this message]

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