linux-kernel - Re: [PATCH] mtd: cfi_cmdset_0002: dynamically determine the max sectors

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Message-ID: <4913398a9317f240235e45f5d1ad886dd8c7e259.camel@infinera.com>
Date:   Fri, 14 Jun 2019 07:18:57 +0000
From:   Joakim Tjernlund <Joakim.Tjernlund@...inera.com>
To:     "richard@....at" <richard@....at>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "vigneshr@...com" <vigneshr@...com>,
        "Chris.Packham@...iedtelesis.co.nz" 
        <Chris.Packham@...iedtelesis.co.nz>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>,
        "dwmw2@...radead.org" <dwmw2@...radead.org>,
        "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "sr@...x.de" <sr@...x.de>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>
Subject: Re: [PATCH] mtd: cfi_cmdset_0002: dynamically determine the max
 sectors

On Fri, 2019-06-14 at 03:23 +0000, Chris Packham wrote:
> 
> 
> Hi All,
> 
> I think this may have got lost in the change of maintainer for mtd.

We need this too, ATM we have a local hack that just changes  MAX_SECTORS to 1024

> 
> On 22/05/19 12:06 PM, Chris Packham wrote:
> > Because PPB unlocking unlocks the whole chip cfi_ppb_unlock() needs to
> > remember the locked status for each sector so it can re-lock the
> > unaddressed sectors. Dynamically calculate the maximum number of sectors
> > rather than using a hardcoded value that is too small for larger chips.
> > 
> > Tested with Spansion S29GL01GS11TFI flash device.
> > 
> > Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
> > ---
> >   drivers/mtd/chips/cfi_cmdset_0002.c | 13 ++++++++-----
> >   1 file changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> > index c8fa5906bdf9..a1a7d334aa82 100644
> > --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> > @@ -2533,8 +2533,6 @@ struct ppb_lock {
> >       int locked;
> >   };
> > 
> > -#define MAX_SECTORS                  512
> > -
> >   #define DO_XXLOCK_ONEBLOCK_LOCK             ((void *)1)
> >   #define DO_XXLOCK_ONEBLOCK_UNLOCK   ((void *)2)
> >   #define DO_XXLOCK_ONEBLOCK_GETLOCK  ((void *)3)
> > @@ -2633,6 +2631,7 @@ static int __maybe_unused cfi_ppb_unlock(struct mtd_info *mtd, loff_t ofs,
> >       int i;
> >       int sectors;
> >       int ret;
> > +     int max_sectors;
> > 
> >       /*
> >        * PPB unlocking always unlocks all sectors of the flash chip.
> > @@ -2640,7 +2639,11 @@ static int __maybe_unused cfi_ppb_unlock(struct mtd_info *mtd, loff_t ofs,
> >        * first check the locking status of all sectors and save
> >        * it for future use.
> >        */
> > -     sect = kcalloc(MAX_SECTORS, sizeof(struct ppb_lock), GFP_KERNEL);
> > +     max_sectors = 0;
> > +     for (i = 0; i < mtd->numeraseregions; i++)
> > +             max_sectors += regions[i].numblocks;
> > +
> > +     sect = kcalloc(max_sectors, sizeof(struct ppb_lock), GFP_KERNEL);
> >       if (!sect)
> >               return -ENOMEM;
> > 
> > @@ -2689,9 +2692,9 @@ static int __maybe_unused cfi_ppb_unlock(struct mtd_info *mtd, loff_t ofs,
> >               }
> > 
> >               sectors++;
> > -             if (sectors >= MAX_SECTORS) {
> > +             if (sectors >= max_sectors) {
> >                       printk(KERN_ERR "Only %d sectors for PPB locking supported!\n",
> > -                            MAX_SECTORS);
> > +                            max_sectors);
> >                       kfree(sect);
> >                       return -EINVAL;
> >               }
> > 
> 
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