fsldma seems to be buggy, noticed in loop mode

Hello,

I have a little kmod where I dma data from one place to another (can
post it if someone wants to see it). It works in general according to
memcmp :)

If I set the DAHE flag (DAHTS = 0, for one byte transfers) everything
seems to work as well (I see only the last byte which has the correct
value).
Now if I change the destination address to my FIFO I get the requested
transfer size plus some extra bytes. The extra bytes are looking like
exactly the same DMA transfer once again. Then my FIFO overruns.
Enabling some printks in the kernel gave me the following log:

|of-fsl-dma-channel e0021100.dma-channe: new link desc alloc df32a000
|of-fsl-dma-channel e0021100.dma-channe: --memcpy issue--
|of-fsl-dma-channel e0021100.dma-channe: Ch 0, LD 1f32a000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 0: 00050000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 1: 1f0be000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 2: 00050000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 3: 1f36c000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 4: 00000000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 5: 00000001
|of-fsl-dma-channel e0021100.dma-channe: LD offset 6: 00000100
|of-fsl-dma-channel e0021100.dma-channe: LD offset 7: 00000000
|of-fsl-dma-channel e0021100.dma-channe: ----------------
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: chan completed_cookie = 1

18 more lines

Hi, Sebastian

Could you please apply these two patches and test again?

http://lkml.org/lkml/2008/3/10/64
http://lkml.org/lkml/2008/3/13/36

Thanks!
Wei.

-----Original Message-----
From: Sebastian Siewior [mailto:<redacted>]=20
Sent: Thursday, March 13, 2008 2:04 AM
To: <redacted>
Cc: Zhang Wei
Subject: fsldma seems to be buggy, noticed in loop mode
=20
Hello,
=20
I have a little kmod where I dma data from one place to another (can
post it if someone wants to see it). It works in general according to
memcmp :)
=20
If I set the DAHE flag (DAHTS =3D 0, for one byte transfers) =

everything

seems to work as well (I see only the last byte which has the correct
value).
Now if I change the destination address to my FIFO I get the requested
transfer size plus some extra bytes. The extra bytes are looking like
exactly the same DMA transfer once again. Then my FIFO overruns.
Enabling some printks in the kernel gave me the following log:
=20
|of-fsl-dma-channel e0021100.dma-channe: new link desc alloc df32a000
|of-fsl-dma-channel e0021100.dma-channe: --memcpy issue--
|of-fsl-dma-channel e0021100.dma-channe: Ch 0, LD 1f32a000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 0: 00050000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 1: 1f0be000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 2: 00050000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 3: 1f36c000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 4: 00000000
|of-fsl-dma-channel e0021100.dma-channe: LD offset 5: 00000001
|of-fsl-dma-channel e0021100.dma-channe: LD offset 6: 00000100
|of-fsl-dma-channel e0021100.dma-channe: LD offset 7: 00000000
|of-fsl-dma-channel e0021100.dma-channe: ----------------
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20
from 0x000000001f32a000
|of-fsl-dma-channel e0021100.dma-channe: xfer LDs staring=20

27 more quoted lines

* Zhang Wei | 2008-03-13 15:03:54 [+0800]:

Could you please apply these two patches and test again?

http://lkml.org/lkml/2008/3/10/64
http://lkml.org/lkml/2008/3/13/36

Ui, that fast. Did you find this on your own or after me reporting that
bug?
It solves my FIFO problem, thanks.

Thanks!
Wei.

 Sebastian

-----Original Message-----
From: Sebastian Siewior [mailto:<redacted>]=20
=20
* Zhang Wei | 2008-03-13 15:03:54 [+0800]:
=20

quoted

Could you please apply these two patches and test again?

http://lkml.org/lkml/2008/3/10/64
http://lkml.org/lkml/2008/3/13/36

Ui, that fast. Did you find this on your own or after me=20
reporting that
bug?
It solves my FIFO problem, thanks.
=20

Just after you reported. :)

Cheers!
Wei.

* Zhang Wei | 2008-03-13 17:17:31 [+0800]:

Just after you reported. :)

okey. Do you want me to add a tested by on lkml?

Cheers!
Wei.

 Sebastian

-----Original Message-----
From: Sebastian Siewior [mailto:<redacted>]=20
=20
* Zhang Wei | 2008-03-13 17:17:31 [+0800]:
=20

quoted

Just after you reported. :)

okey. Do you want me to add a tested by on lkml?
=20

it's my pleasure!

Thanks!
Wei