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

Sinan Kaya okaya at codeaurora.org
Tue Dec 8 06:33:45 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 work on it.

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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