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SubjectRe: [PATCH] staging:mt29f_spinand: MT29F2G failing as only 16-bit arguments and variables used for addressing.
On Mon, 6 Aug 2018 15:01:37 +0300
Dan Carpenter <dan.carpenter@oracle.com> wrote:

> On Mon, Aug 06, 2018 at 01:46:48PM +0200, Boris Brezillon wrote:
> > 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.
> >
>
> It sure looks like it can be in nand_exit_status_op()...

True, but nand_exit_status_op() won't be called here. It's only used
when the NAND controller driver is implementing ->exec_op() and needs
to do status polling, and from the micron NAND code that deals with raw
NAND chips with on-die ECC (the mt29f driver is supposed to deal with
SPI NANDs).

>
> > 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.
>
> I don't think we should make the code more complicated than necessary
> just to make static checkers happy. When you say "this driver", you
> mean the staging driver?

Yes.

> In that case, there is no need to revert
> commit 6efb21d6d0e7 ("staging:mt29f_spinand: MT29F2G failing as only 16
> bits used for addressing.").

Okay.

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