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Date: Thu, 16 May 2024 13:48:36 +0200
From: Sascha Hauer <s.hauer@pengutronix.de>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	Richard Weinberger <richard@nod.at>
Subject: Re: [PATCH] mtd: rawnand: onfi: read parameter pages in one go
Message-ID: <ZkXylC2xrlqGW_xV@pengutronix.de>
References: <20240514134140.1050141-1-s.hauer@pengutronix.de>
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 <20240516115812.02908822@xps-13>
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On Thu, May 16, 2024 at 11:58:12AM +0200, Miquel Raynal wrote:
> 
> miquel.raynal@bootlin.com wrote on Thu, 16 May 2024 10:13:50 +0200:
> 
> > Hi Sascha,
> > 
> > s.hauer@pengutronix.de wrote on Tue, 14 May 2024 15:41:40 +0200:
> > 
> > > nand_read_data_op() is not supported by all NAND controllers.
> > > nand_change_read_column_op() is not supported or at least is hard to
> > > support by NAND controllers that use a different page layout than
> > > expected by the NAND core.  
> > 
> > I'm sorry but RNDOUT is not so hard to support, and I know no NAND
> > controller without this feature (I think even the first mxc controller
> > supports it?). However, the command does not exist on small page NANDs
> > (512 bytes).
> 
> Nevermind, the ONFI spec (in all versions) states that RNDOUT are
> allowed during parameter page reads, regardless of the size of the chip
> (at least, that is not mentioned).

I could imagine that there are no ONFI compliant chips with small pages,
I don't know how to verify this though.

Anyway, this was a try to make reading the parameter pages a bit more
straight forward. It seems the MXC NAND controller can't support reading
three parameter pages in one go either. It works in software ECC mode
because I reverse the syndome type layout the controller introduces, but
it can't work with hardware ECC. So disregard this patch.

Sascha

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