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

Message ID 20191209094332.4047-6-peter.ujfalusi@ti.com
State Accepted
Commit 6755ec06d1333765d2b935e4e4a5bd011332bac6
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Series
  • Untitled series #25494
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Commit Message

Peter Ujfalusi Dec. 9, 2019, 9:43 a.m.
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(+)

-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Comments

Peter Ujfalusi Dec. 20, 2019, 8:49 a.m. | #1
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?

- P├ęter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Vinod Koul Dec. 20, 2019, 9:57 a.m. | #2
On 20-12-19, 10:49, Peter Ujfalusi wrote:

> >> +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


not sure I follow, but dma_set_residue() in already in drivers/dma/dmaengine.h

> dma_set_in_flight_bytes() there as well?


-- 
~Vinod

Patch

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;
+}
+
 struct dmaengine_desc_callback {
 	dma_async_tx_callback callback;
 	dma_async_tx_callback_result callback_result;
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 0e8b426bbde9..c4c5219030a6 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -682,11 +682,13 @@  static inline struct dma_async_tx_descriptor *txd_next(struct dma_async_tx_descr
  * @residue: the remaining number of bytes left to transmit
  *	on the selected transfer for states DMA_IN_PROGRESS and
  *	DMA_PAUSED if this is implemented in the driver, else 0
+ * @in_flight_bytes: amount of data in bytes cached by the DMA.
  */
 struct dma_tx_state {
 	dma_cookie_t last;
 	dma_cookie_t used;
 	u32 residue;
+	u32 in_flight_bytes;
 };
 
 /**