Re: [PATCH v2] mtd: rawnand: marvell: check for RDY bits after enabling the IRQ

[Boris Brezillon <boris.brezillon@bootlin.com>]

On Thu, 27 Sep 2018 10:11:45 +0200
Miquel Raynal <miquel.raynal@bootlin.com> wrote:

> Hi Daniel,
> 
> Daniel Mack <daniel@zonque.org> wrote on Thu, 27 Sep 2018 09:17:51
> +0200:
> 
> > At least on PXA3xx platforms, enabling RDY interrupts in the NDCR register
> > will only cause the IRQ to latch when the RDY lanes are changing, and not
> > in case they are already asserted.
> > 
> > This means that if the controller finished the command in flight before
> > marvell_nfc_wait_op() is called, that function will wait for a change in
> > the bit that can't ever happen as it is already set.
> > 
> > To address this race, check for the RDY bits after the IRQ was enabled,
> > and complete the completion immediately if the condition is already met.
> > 
> > This fixes a bug that was observed with a NAND chip that holds a UBIFS
> > parition on which file system stress tests were executed. When
> > marvell_nfc_wait_op() reports an error, UBI/UBIFS will eventually mount
> > the filesystem read-only, reporting lots of warnings along the way.
> > 
> > Fixes: 02f26ecf8c77 mtd: nand: add reworked Marvell NAND controller driver
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Daniel Mack <daniel@zonque.org>
> > ---  
> 
> Sorry I haven't had the time to check on my Armada, but you figured it
> out, and the fix looks good to me!
> 
> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
> 
> Boris, do you plan to send another fixes PR of can I take it into
> the nand/next branch?

Queued to mtd/master.

Thanks,

Boris