Commit 156ae092 authored Dec 15, 2016 by Shawn Guo Committed by Vinod Koul Jan 02, 2017

dmaengine: zx: fix residue calculation



The dma residue is defined as the free space to end of transfer buffer,
which could be multiple segments chained together.  So the residue
calculation in zx_dma_tx_status() works for both slave_sg and cyclic
case.  But unfortunately, the 'index' is wrong.  It should plus one,
because the current segment is already occupied and shouldn't be counted
into free space.

This fixes the HDMI audio noise issue we see on ZX296718 with SPDIF
interface.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

parent fc318d64

drivers/dma/zx_dma.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -365,7 +365,8 @@ static enum dma_status zx_dma_tx_status(struct dma_chan *chan,

		bytes = 0;
		clli = zx_dma_get_curr_lli(p);
		index = (clli - ds->desc_hw_lli) / sizeof(struct zx_desc_hw);
		index = (clli - ds->desc_hw_lli) /
		sizeof(struct zx_desc_hw) + 1;
		for (; index < ds->desc_num; index++) {
		bytes += ds->desc_hw[index].src_x;
		/* end of lli */

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