Using GPMI-NAND driver on iMX28 using 3.4-rc1?

[Vinod Koul]

On Thu, 2012-04-05 at 06:02 -0700, Sam Gandhi wrote:
> Vinod,
> 
> On Thu, Apr 5, 2012 at 5:27 AM, Vinod Koul <vinod.koul at linux.intel.com> wrote:
> > On Thu, 2012-04-05 at 05:03 -0700, Sam Gandhi wrote:
> >> 2012/4/4 Huang Shijie <b32955 at freescale.com>:
> >> > Hi All:
> >> >> On Wed, Apr 4, 2012 at 7:07 PM, Sam Gandhi<samgandhi9 at gmail.com>  wrote:
> >> >>
> >> >>> I reverted that commit and I still see following  error!
> >> >> Huang,
> >> >>
> >> >> Are you able to use gpmi on mx28 running 3.4-rc1?
> >> >>
> >> > I also meet the same problem today.
> >> >
> >> >
> >> >>> flash_erase /dev/mtd1 0 0
> >> >>> Erasing 1------------[ cut here ]------------
> >> >>> kernel BUG at /home/sam/linux/drivers/dma/dmaengine.h:53!
> >> > the mxs-dma has added some patches about the cookie.
> >> > The bug is in the dmaengine.h.
> >> >
> >> > So let more people know this bug.
> >> >
> >> > BR
> >> > Huang Shijie
> >> >
> >> >
> >> FWIW, Just a data point.
> >>
> >> I coverted BUG_ON in dmaengine.h to printk as shown below. With this
> >> change I was able to format nand, create UBI partition. I have been
> >> running UBI torture test called integck on my board that does lot of
> >> I/O, mounting/unmounting of filesystem for close to 8 hour now without
> >> crash. But I do see those printks. I haven't followed logic of
> >> tx->cookie well enough to figure out what the appropriate change
> >> should be. Note this is with commit
> >> 00292bbf769620dea923dbd906afd88955f7ea19 reverted in my tree.
> >>
> >> Cookie 0  completed 102118268 DMA_MIN 1
> >> Cookie 0  completed 102120401 DMA_MIN 1
> >> Cookie 0  completed 102237726 DMA_MIN 1
> >>
> >> git diff drivers/dma/dmaengine.h
> >> diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
> >> index 17f983a..3d10a70 100644
> >> --- a/drivers/dma/dmaengine.h
> >> +++ b/drivers/dma/dmaengine.h
> >> @@ -50,7 +50,11 @@ static inline dma_cookie_t dma_cookie_assign(struct
> >> dma_async_tx_descriptor *tx)
> >>   */
> >>  static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
> >>  {
> >> -       BUG_ON(tx->cookie < DMA_MIN_COOKIE);
> >> +       if ( tx->cookie < DMA_MIN_COOKIE)
> >> +               printk(KERN_ERR "Cookie %d,  completed %d DMA_MIN %d
> >> ",tx->cookie,
> >> +               tx->chan->completed_cookie,
> >> +               DMA_MIN_COOKIE);
> >> +       /* BUG_ON(tx->cookie < DMA_MIN_COOKIE); */
> >>         tx->chan->completed_cookie = tx->cookie;
> >>         tx->cookie = 0;
> >>  }
> > This means you are trying to mark a cookie complete when it is already
> > marked so!, hence dmaengine screams.
> > The bug is is mxs-dma.
> > Let me know if below fixes it (assuming you are not using cyclic API,
> > that would need fixup as well)
> >
> > diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
> > index c81ef7e..5ddd84e 100644
> > --- a/drivers/dma/mxs-dma.c
> > +++ b/drivers/dma/mxs-dma.c
> > @@ -399,6 +399,10 @@ static struct dma_async_tx_descriptor
> > *mxs_dma_prep_slave_sg(
> >                ccw->bits &= ~CCW_DEC_SEM;
> >        } else {
> >                idx = 0;
> > +               /* assign cookie here,
> > +                * hopefully for above case we dont need it
> > +                */
> > +               dma_cookie_assign(&mxs_chan->desc);
> >        }
> >
> >        if (direction == DMA_TRANS_NONE) {
> >
> I applied your suggested change and don't hit the BUG_ON in
> dmaengine.h with this change UBI torture test has run for last 30 min
> or so I will let it run for a day. [ I will let mxs-dma authors
> comment if this is a right change.. ]
Good I will apply this and send to Linus.
Care to give your tested-by.


-- 
~Vinod