From: Andy Shevchenko Date: Fri, 18 Mar 2016 12:26:33 +0000 (+0200) Subject: dmaengine: hsu: correct residue calculation of active descriptor X-Git-Tag: v4.5.3~172 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=390cb9a6064eed7b197e926137293ffbfb2eb3d8;p=thirdparty%2Fkernel%2Fstable.git dmaengine: hsu: correct residue calculation of active descriptor commit a197f3c7d48c0c1f45076ea47533a76ba9b1a959 upstream. The commit f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation") speeded up calculation of the queued descriptor but broke the initial residue value for active descriptor. In accordance with documentation the hardware descriptor is updated each time DMA transfered some bytes. It means we have to calculate a sum of lengths of non-submitted hardware descriptors and whatever current values in the hardware. Do this straightforward. Fixes: f0579c8ceaf1 ("dmaengine: hsu: speed up residue calculation") Signed-off-by: Andy Shevchenko Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/dma/hsu/hsu.c b/drivers/dma/hsu/hsu.c index 5a6817a05e2ba..025d375fc3d76 100644 --- a/drivers/dma/hsu/hsu.c +++ b/drivers/dma/hsu/hsu.c @@ -254,10 +254,13 @@ static void hsu_dma_issue_pending(struct dma_chan *chan) static size_t hsu_dma_active_desc_size(struct hsu_dma_chan *hsuc) { struct hsu_dma_desc *desc = hsuc->desc; - size_t bytes = desc->length; + size_t bytes = 0; int i; - i = desc->active % HSU_DMA_CHAN_NR_DESC; + for (i = desc->active; i < desc->nents; i++) + bytes += desc->sg[i].len; + + i = HSU_DMA_CHAN_NR_DESC - 1; do { bytes += hsu_chan_readl(hsuc, HSU_CH_DxTSR(i)); } while (--i >= 0);