Re: [PATCH v4 02/14] dmaengine: tegra-apb: Implement synchronization callback

[Jon Hunter]

On 14/01/2020 21:02, Dmitry Osipenko wrote:
> 14.01.2020 18:15, Jon Hunter ÐÐÑÐÑ:
>>
>> On 12/01/2020 17:29, Dmitry Osipenko wrote:
>>> The ISR tasklet could be kept scheduled after DMA transfer termination,
>>> let's add synchronization callback which blocks until tasklet is finished.
>>>
>>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>>> ---
>>>  drivers/dma/tegra20-apb-dma.c | 8 ++++++++
>>>  1 file changed, 8 insertions(+)
>>>
>>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
>>> index 319f31d27014..664e9c5df3ba 100644
>>> --- a/drivers/dma/tegra20-apb-dma.c
>>> +++ b/drivers/dma/tegra20-apb-dma.c
>>> @@ -798,6 +798,13 @@ static int tegra_dma_terminate_all(struct dma_chan *dc)
>>>  	return 0;
>>>  }
>>>  
>>> +static void tegra_dma_synchronize(struct dma_chan *dc)
>>> +{
>>> +	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
>>> +
>>> +	tasklet_kill(&tdc->tasklet);
>>> +}
>>> +
>>
>> Wouldn't there need to be some clean-up here? If the tasklet is
>> scheduled, seems that there would be some other house-keeping that needs
>> to be done after killing it.
> 
> I'm not seeing anything to clean-up, could you please clarify?

Clean-up with regard to the descriptors. I was concerned if you will the
tasklet the necessary clean-up of the descriptors is not handled.

Jon

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