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Date:   Mon, 6 Aug 2018 13:46:48 +0200
From:   Boris Brezillon <boris.brezillon@bootlin.com>
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     Jheng-Jhong Wu <goodwater.wu@gmail.com>,
        Palle Christensen <palle.christensen@microsemi.com>,
        devel@driverdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Arun Nagendran <arunrasppi@gmail.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>
Subject: Re: [PATCH] staging:mt29f_spinand: MT29F2G failing as only 16-bit
 arguments and variables used for addressing.
Message-ID: <20180806134648.2976de9e@bbrezillon>
In-Reply-To: <20180801120551.ju6zhxhoef6w5zim@mwanda>
References: <1533093861-9761-1-git-send-email-goodwater.wu@gmail.com>
        <20180801120551.ju6zhxhoef6w5zim@mwanda>
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Hi Dan,

On Wed, 1 Aug 2018 15:05:51 +0300
Dan Carpenter <dan.carpenter@oracle.com> wrote:

> On Wed, Aug 01, 2018 at 11:24:19AM +0800, Jheng-Jhong Wu wrote:
> > For NAND flash chips with more than 1Gbit (e.g. MT29F2G) more than 16 bits
> > are necessary to address the correct page. The driver sets the address for
> > more than 16 bits, but it uses 16-bit arguments and variables (these are
> > page_id, block_id, row) to do address operations. Obviously, these
> > arguments and variables cannot deal with more than 16-bit address.
> > 
> > Signed-off-by: Jheng-Jhong Wu <goodwater.wu@gmail.com>  
> 
> This seems reasonable...  It would be needed to make commit 6efb21d6d0e7
> ("staging:mt29f_spinand: MT29F2G failing as only 16 bits used for
> addressing.") work.  It also fixes a static checker warning.
> 
> My only concern is that the mtd/nand code seems to use -1 as a magical
> page_id.  For example:

Yes, -1 means "don't issue the row/page address cycles", though I
don't think page can be -1 for NAND_CMD_READ{1,0} commands.

Anyway, if you want this patch merged to fix a static checker warning,
I'm fine with that. In any case, I still plan to send a patch removing
this driver for v4.20, so, anyone using this driver should start
testing the new SPI NAND driver (drivers/mtd/nand/spi) and tweak/fix
the new implementation if needed.

Regards,

Boris