Commit a1cf0903 authored Sep 15, 2015 by Maxime Ripard Committed by Vinod Koul Oct 01, 2015

dmaengine: at_xdmac: change block increment addressing mode



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: 6007ccb5 ("dmaengine: xdmac: Add interleaved transfer support")
Cc: stable@vger.kernel.org #4.2
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

parent 6bea0f6d

drivers/dma/at_xdmac.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -875,14 +875,14 @@ at_xdmac_interleaved_queue_desc(struct dma_chan *chan,

	if (xt->src_inc) {		if (xt->src_inc) {
	if (xt->src_sgl)		if (xt->src_sgl)
	chan_cc \|= AT_XDMAC_CC_SAM_UBS_DS_AM;		chan_cc \|= AT_XDMAC_CC_SAM_UBS_AM;
	else		else
	chan_cc \|= AT_XDMAC_CC_SAM_INCREMENTED_AM;		chan_cc \|= AT_XDMAC_CC_SAM_INCREMENTED_AM;
	}		}

	if (xt->dst_inc) {		if (xt->dst_inc) {
	if (xt->dst_sgl)		if (xt->dst_sgl)
	chan_cc \|= AT_XDMAC_CC_DAM_UBS_DS_AM;		chan_cc \|= AT_XDMAC_CC_DAM_UBS_AM;
	else		else
	chan_cc \|= AT_XDMAC_CC_DAM_INCREMENTED_AM;		chan_cc \|= AT_XDMAC_CC_DAM_INCREMENTED_AM;
	}		}

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