Re: [PATCH] - change calculating of position page containing BBM

[Piotr Sroka]

Hello

The 09/19/2019 13:33, Schrempf Frieder wrote:
> EXTERNAL MAIL
>
>
> On 19.09.19 15:18, Miquel Raynal wrote:
> > Hello,
> >
> > Schrempf Frieder <frieder.schrempf@xxxxxxxxxx> wrote on Thu, 19 Sep
> > 2019 13:15:08 +0000:
> >
> > > On 19.09.19 14:58, Miquel Raynal wrote:
> > > > Hi Piotr,
> > > >
> > > > Piotr Sroka <piotrs@xxxxxxxxxxx> wrote on Thu, 19 Sep 2019 13:41:35
> > > > +0100:
> > > >
> > > > > Change calculating of position page containing BBM
> > > > >
> > > > > If none of BBM flags is set then function nand_bbm_get_next_page
> > > > > reports EINVAL. It causes that BBM is not read at all during scanning
> > > > > factory bad blocks. The result is that the BBT table is build without
> > > > > checking factory BBM at all. For Micron flash memories none of this
> > > > > flag is set if page size is different than 2048 bytes.
> > >
> > > I wonder if it wouldn't be better to fix the Micron driver instead:
> > >
> > > --- a/drivers/mtd/nand/raw/nand_micron.c
> > > +++ b/drivers/mtd/nand/raw/nand_micron.c
> > > @@ -448,6 +448,8 @@ static int micron_nand_init(struct nand_chip *chip)
> > >
> > >           if (mtd->writesize == 2048)
> > >                   chip->options |= NAND_BBM_FIRSTPAGE |
> > >                                    NAND_BBM_SECONDPAGE;
> > > +       else
> > > +               chip->options |= NAND_BBM_FIRSTPAGE;
> >
> > That's what I forgot in my last answer to this thread, I think I only
> > told Piotr privately: I would like both. I think it is important to fix
> > the bbm_get_next_page function but for clarity, setting the FIRSTPAGE
> > flag in Micron's driver seems also pertinent.
>
> Indeed, that sounds reasonable. Piotr, can you send another patch with
> the diff above? And by the way: thanks for fixing my code ;)
>
> Reviewed-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
Thanks Frieder and Miquel for the very quick reply. I will send next
version containing Micron driver fix.

> > >           ondie = micron_supports_on_die_ecc(chip);
> > >
> > >
> > > > "none of these flags are set"
> > > >
> > > > > This patch changes the nand_bbm_get_next_page function.
> > > >
> > > > "Address this regression by changing the
> > > > nand_bbm_get_next_page_function."
> > > >
> > > > > It will return 0 if none of BBM flag is set and page parameter is 0.
> > > >
> > > >                         no BBM flag is set
> > > >
> > > > > After that modification way of discovering factory bad blocks will work
> > > > > similar as in kernel version 5.1.
> > > >
> > > > Fixes + stable tags would be great!
Ok I will add fixes tag and "Cc: <stable@xxxxxxxxxxxxxxx>". 

> > > > > Signed-off-by: Piotr Sroka <piotrs@xxxxxxxxxxx>
> > > > > ---
> > > > >    drivers/mtd/nand/raw/nand_base.c | 8 ++++++--
> > > > >    1 file changed, 6 insertions(+), 2 deletions(-)
> > > > >
> > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > > > > index 5c2c30a7dffa..f64e3b6605c6 100644
> > > > > --- a/drivers/mtd/nand/raw/nand_base.c
> > > > > +++ b/drivers/mtd/nand/raw/nand_base.c
> > > > > @@ -292,12 +292,16 @@ int nand_bbm_get_next_page(struct nand_chip *chip, int page)
> > > > >    	struct mtd_info *mtd = nand_to_mtd(chip);
> > > > >    	int last_page = ((mtd->erasesize - mtd->writesize) >>
> > > > >    			 chip->page_shift) & chip->pagemask;
> > > > > +	unsigned int bbm_flags = NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE
> > > > > +		| NAND_BBM_LASTPAGE;
> > > > >
> > > > > +	if (page == 0 && !(chip->options & bbm_flags))
> > > > > +		return 0;
> > > > >    	if (page == 0 && chip->options & NAND_BBM_FIRSTPAGE)
> > > > >    		return 0;
> > > > > -	else if (page <= 1 && chip->options & NAND_BBM_SECONDPAGE)
> > > > > +	if (page <= 1 && chip->options & NAND_BBM_SECONDPAGE)
> > > > >    		return 1;
> > > > > -	else if (page <= last_page && chip->options & NAND_BBM_LASTPAGE)
> > > > > +	if (page <= last_page && chip->options & NAND_BBM_LASTPAGE)
> > > > >    		return last_page;
> > > > >
> > > > >    	return -EINVAL;
> > > >
> > > > Lookgs good otherwise.
> > > >
> > > > Thanks,
> > > > MiquÃl
> >
> > Thanks,
> > MiquÃl

Thanks,
Piotr