Re: [PATCH 1/1] dma: edma: fix incorrect SG list handling

[Sekhar Nori <nsekhar@ti.com>]

On Monday 14 April 2014 02:27 PM, Vinod Koul wrote:
> On Mon, Apr 14, 2014 at 02:01:11PM +0530, Sekhar Nori wrote:
>> Vinod,
>>
>> On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote:
>>> The code to handle any length SG lists calls edma_resume()
>>> even before edma_start() is called. This is incorrect
>>> because edma_resume() enables edma events on the channel
>>> after which CPU (in edma_start) cannot clear posted
>>> events by writing to ECR (per the EDMA user's guide).
>>>
>>> Because of this EDMA transfers fail to start if due
>>> to some reason there is a pending EDMA event registered
>>> even before EDMA transfers are started. This can happen if
>>> an EDMA event is a byproduct of device initialization.
>>>
>>> Fix this by calling edma_resume() only if it is not the
>>> first batch of MAX_NR_SG elements.
>>>
>>> Without this patch, MMC/SD fails to function on DA850 EVM
>>> with DMA. The behaviour is triggered by specific IP and
>>> this can explain why the issue was not reported before
>>> (example with MMC/SD on AM335x).
>>>
>>> Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card.
>>>
>>> Cc: stable@vger.kernel.org # v3.12.x+
>>> Cc: Joel Fernandes <joelf@ti.com>
>>> Acked-by: Joel Fernandes <joelf@ti.com>
>>> Tested-by: Jon Ringle <jringle@gridpoint.com>
>>> Tested-by: Alexander Holler <holler@ahsoftware.de>
>>> Reported-by: Jon Ringle <jringle@gridpoint.com>
>>> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
>>
>> Looks like this patch is not in mainline still?
> 
> Sorry looks like I have missed sending the email. I had applied it last week and
> today rebased after rc1. It would be part of rc2...

Thank you!

Regards,
Sekhar