[PATCH V7 3/3] dma: add Qualcomm Technologies HIDMA channel driver

Sinan Kaya okaya at codeaurora.org
Thu Dec 10 12:10:48 PST 2015

On 12/5/2015 3:00 AM, Vinod Koul wrote:
> On Wed, Dec 02, 2015 at 02:04:05PM -0500, Sinan Kaya wrote:
>>>>> You are missing the point. Channel can be paused, yes but the descriptor
>>>>> is in queue and is not paused. The descriptor running is paused, yes.
>>>>> There is subtle difference between these
>>> I'll follow your recommendation. PAUSE for the currently active
>>> descriptor and DMA_IN_PROGRESS for the rest.
>> I'm now confused.
>> I looked at several DMA driver implementations.
>> 1. They call dma_cookie_status function to see if the job is done.
>> 2. If done, they return right ahead.
>> 3. Otherwise, dma_cookie_status returns DMA_IN_PROGRESS.
>> 4. Next the code checks if the channel is paused and return value is
>> DMA_IN_PROGRESS. The code changes return code to DMA_PAUSED.
>> Whereas, I was returning paused first before even checking if the
>> descriptor is done. Are you OK with the sequence 1..4 above?
> Yes am okay with this with slight change in 4.
> You should set to PAUSED only for current descriptor and not for the ones in
> queue

OK. I'll post a new version with this. Is there any other comment that
needed to be addressed?

Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project

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