Re: [PATCH] mtd: rawnand: marvell: fix the IRQ handler complete() condition

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

On Wed,  3 Oct 2018 11:05:04 +0200
Miquel Raynal <miquel.raynal@bootlin.com> wrote:

> With the current implementation, the complete() in the IRQ handler is
> supposed to be called only if the register status has one or the other
> RDY bit set. Other events might trigger an interrupt as well if
> enabled, but should not end-up with a complete() call.
> 
> For this purpose, the code was checking if the other bits were set, in
> this case complete() was not called. This is wrong as two events might
> happen in a very tight time-frame and if the NDSR status read reports
> two bits set (eg. RDY(0) and RDDREQ) at the same time, complete() was
> not called.
> 
> This logic would lead to timeouts in marvell_nfc_wait_op() and has
> been observed on PXA boards (NFCv1) in the Hamming write path.
> 
> Fixes: 02f26ecf8c77 ("mtd: nand: add reworked Marvell NAND controller driver")
> Cc: stable@vger.kernel.org
> Reported-by: Daniel Mack <daniel@zonque.org>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Tested-by: Daniel Mack <daniel@zonque.org>

Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>

> ---
>  drivers/mtd/nand/raw/marvell_nand.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
> index bc2ef5209783..c7573ccdbacd 100644
> --- a/drivers/mtd/nand/raw/marvell_nand.c
> +++ b/drivers/mtd/nand/raw/marvell_nand.c
> @@ -686,7 +686,7 @@ static irqreturn_t marvell_nfc_isr(int irq, void *dev_id)
>  
>  	marvell_nfc_disable_int(nfc, st & NDCR_ALL_INT);
>  
> -	if (!(st & (NDSR_RDDREQ | NDSR_WRDREQ | NDSR_WRCMDREQ)))
> +	if (st & (NDSR_RDY(0) | NDSR_RDY(1)))
>  		complete(&nfc->complete);
>  
>  	return IRQ_HANDLED;