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Date: Wed, 5 Jul 2017 11:18:52 -0700
From: Brian Norris <computersforpeace@gmail.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Karl Beldan <karl.beldan@gmail.com>, linux-mtd@lists.infradead.org,
 bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org,
 Kamal Dasu <kdasu.kdev@gmail.com>,
 Boris Brezillon <boris.brezillon@free-electrons.com>,
 Richard Weinberger <richard@nod.at>, David Woodhouse <dwmw2@infradead.org>,
 Marek Vasut <marek.vasut@gmail.com>,
 Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
 Karl Beldan <karl.beldan+oss@gmail.com>
Subject: Re: [PATCH] brcmnand: Fix up the flash cache register offset for
 older controllers
Message-ID: <20170705181852.GA117111@google.com>
References: <20170705174653.21797-1-karl.beldan+oss@gmail.com>
 <7f7804da-e431-f197-31b9-c98359b9151a@gmail.com>
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Ha, I was in the middle of writing essentially this :)

On Wed, Jul 05, 2017 at 11:15:01AM -0700, Florian Fainelli wrote:
> On 07/05/2017 10:46 AM, Karl Beldan wrote:
> > From: Karl Beldan <karl.beldan-ext@sagemcom.com>
> > 
> > Tested on BCM{63138,6838,63268} and cross checked with the various
> > *_map_part.h which the brcmnand_regs_v* in brcmnand.c have historically
> > been derived from.
> 
> BCM63138 is using a 7.0 controller, 6838 uses a 5.0 controller, but has
> a separate flash cache register which does indeed end up at 0x400 bytes
> off the main FLASH block, and finally 63268 does have a v4.0 controller
> and the flash cache is also in a separate register that makes it end up
> at 0x400.

The joy of arbitrarily-changing IP, since of course business units
within a company (or even divisions within the same business unit) would
never want to share software...

> Your change, as proposed would break chips like 7425 which use 5.0
> controller with the flash cache at 0x200 bytes.
> 
> The binding describes an optional flash-cache register cell that you can
> specify, so that's probably what you want to do here?

What he said ^^^

The "nand-cache" register range sounds like what you're looking for.

Brian