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dmaengine: hsu: correct residue calculation of active descriptor 

The commit f0579c8cea ("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: f0579c8cea ("dmaengine: hsu: speed up residue calculation")
Cc: stable@vger.kernel.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Andy Shevchenko 2016-03-18 14:26:33 +02:00 committed by Vinod Koul
parent 080edf75d3
commit a197f3c7d4
1 changed files with 5 additions and 2 deletions
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7
drivers/dma/hsu/hsu.c
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@ -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);