From patchwork Thu Apr  5 12:03:54 2012
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Subject: Using GPMI-NAND driver on iMX28 using 3.4-rc1?
Date: Thu, 05 Apr 2012 02:03:54 -0000
From: Sam Gandhi <samgandhi9@gmail.com>
X-Patchwork-Id: 150943
Message-Id: <CAOdLEaoy8ARS=awimR6fN8EcX+FrqxaSr3VUG3rP3zrNLOf+Gw@mail.gmail.com>
To: Huang Shijie <b32955@freescale.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
 Vinod Koul <vinod.koul@intel.com>, Wolfram Sang <w.sang@pengutronix.de>, 
 linux-mtd@lists.infradead.org, Shawn Guo <shawn.guo@freescale.com>,
 Fabio Estevam <festevam@gmail.com>, "linux-arm-kernel@lists.infradead.org"
 <linux-arm-kernel@lists.infradead.org>

2012/4/4 Huang Shijie <b32955@freescale.com>:
> Hi All:
>> On Wed, Apr 4, 2012 at 7:07 PM, Sam Gandhi<samgandhi9@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
        tx->cookie = 0;
 }

Regards,
-Sam


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;