Re: [PATCH v7 05/12] dmaengine: Add support for reporting DMA cached data amount

Peter Ujfalusi
2019-12-20T08:49:53Z

On 20/12/2019 10.37, Vinod Koul wrote:
> On 09-12-19, 11:43, Peter Ujfalusi wrote:
>> A DMA hardware can have big cache or FIFO and the amount of data sitting in
>> the DMA fabric can be an interest for the clients.
>>
>> For example in audio we want to know the delay in the data flow and in case
>> the DMA have significantly large FIFO/cache, it can affect the latenc/delay
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> Reviewed-by: Tero Kristo <t-kristo@ti.com>
>> ---
>> drivers/dma/dmaengine.h | 8 ++++++++
>> include/linux/dmaengine.h | 2 ++
>> 2 files changed, 10 insertions(+)
>>
>> diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
>> index 501c0b063f85..b0b97475707a 100644
>> --- a/drivers/dma/dmaengine.h
>> +++ b/drivers/dma/dmaengine.h
>> @@ -77,6 +77,7 @@ static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
>> state->last = complete;
>> state->used = used;
>> state->residue = 0;
>> + state->in_flight_bytes = 0;
>> }
>> return dma_async_is_complete(cookie, complete, used);
>> }
>> @@ -87,6 +88,13 @@ static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
>> state->residue = residue;
>> }
>>
>> +static inline void dma_set_in_flight_bytes(struct dma_tx_state *state,
>> + u32 in_flight_bytes)
>> +{
>> + if (state)
>> + state->in_flight_bytes = in_flight_bytes;
>> +}
>
> This would be used by dmaengine drivers right, so lets move it to drivers/dma/dmaengine.h
>
> lets not expose this to users :)

I have put it where the dma_set_residue() was.
I can add a patch first to move dma_set_residue() then add
dma_set_in_flight_bytes() there as well?

- Péter