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

[Sam Gandhi]

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;
 }

Regards,
-Sam