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[PATCH 2/4] dmaengine: at_xdmac: change block increment addressing mode

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From: Maxime Ripard <maxime.ripard@free-electrons.com>

The addressing mode we were using was not only incrementing the address at
each microblock, but also at each data boundary, which was severely slowing
the transfer, without any benefit since we were not using the data stride.

Switch to the micro block increment only in order to get back to an
acceptable performance level.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: 6007ccb57744 ("dmaengine: xdmac: Add interleaved transfer support")
Cc: stable@vger.kernel.org #4.2
---
 drivers/dma/at_xdmac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 0190d1c..3952bff 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -875,14 +875,14 @@ at_xdmac_interleaved_queue_desc(struct dma_chan *chan,
 
 	if (xt->src_inc) {
 		if (xt->src_sgl)
-			chan_cc |=  AT_XDMAC_CC_SAM_UBS_DS_AM;
+			chan_cc |=  AT_XDMAC_CC_SAM_UBS_AM;
 		else
 			chan_cc |=  AT_XDMAC_CC_SAM_INCREMENTED_AM;
 	}
 
 	if (xt->dst_inc) {
 		if (xt->dst_sgl)
-			chan_cc |=  AT_XDMAC_CC_DAM_UBS_DS_AM;
+			chan_cc |=  AT_XDMAC_CC_DAM_UBS_AM;
 		else
 			chan_cc |=  AT_XDMAC_CC_DAM_INCREMENTED_AM;
 	}
-- 
2.5.0

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Thread

[PATCH 0/4] at_xdmac: improvment and fixes for the interleaved mode Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-09-15 15:30 +0200
  [PATCH 1/4] dmaengine: at_xdmac: handle numf > 1 Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-09-15 15:30 +0200
  [PATCH 4/4] dmaengine: at_xdmac: clean used descriptor Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-09-15 15:40 +0200
  [PATCH 2/4] dmaengine: at_xdmac: change block increment addressing mode Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-09-15 15:40 +0200
  [PATCH 3/4] dmaengine: at_xdmac: fix memory leak in interleaved mode Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-09-15 15:40 +0200

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