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Date: Mon, 15 Jan 2018 14:19:00 +0100
From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Han Xu <han.xu@nxp.com>
Cc: Miquel RAYNAL <miquel.raynal@free-electrons.com>, Richard Weinberger
 <richard@nod.at>, David Woodhouse <dwmw2@infradead.org>, Brian Norris
 <computersforpeace@gmail.com>, Marek Vasut <marek.vasut@gmail.com>, Cyrille
 Pitchen <cyrille.pitchen@wedev4u.fr>, linux-mtd@lists.infradead.org
Subject: Re: [PATCH 1/2] mtd: nand: Check ONFI timings have been acked by
 the chip
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Hi Han,

On Mon, 8 Jan 2018 14:04:29 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> On Fri, 5 Jan 2018 16:42:39 +0100
> Miquel RAYNAL <miquel.raynal@free-electrons.com> wrote:
> 
> > Hello,
> >   
> > > Hm, I'm not sure this is safe. The spec says that new ONFI timing mode
> > > is applied as soon the CS line is released after a
> > > SET_FEATURES(ONFI_FEATURE_ADDR_TIMING_MODE), and since we have no
> > > guarantee that the CS will be kept low by the controller after    
> > > ->onfi_set_features() returns we must assume the new mode has been      
> > > applied and call ->setup_data_interface() to instruct the controller
> > > to apply new timings.
> > > 
> > > If you want to check if the mode has really been applied, you should
> > > release the CS (->select_chip(-1)), re-acquire it
> > > (->select_chip(X)), and call    
> > > ->onfi_get_features(ONFI_FEATURE_ADDR_TIMING_MODE). If it appears    
> > > that the mode has not been applied, you should restore timing mode 0
> > > and issue a RESET.    
> > 
> > Boris, thanks for the comment, I will fix that.
> > 
> > Han, could I have your input on this series? Aside Boris' comment of
> > course.  
> 
> Han, we really need your feedback on this series since you were the one
> complaining that ONFI mode should be checked back after applying a new
> mode. Miquel is reworking the framework to mimic what the GPMI driver,
> but we need to be sure that you'll accept to transition to the generic
> ->setup_data_interface() solution.

Gentle ping.