dmaengine: hsu: correct residue calculation of active descriptor
authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Fri, 18 Mar 2016 12:26:33 +0000 (14:26 +0200)
committerVinod Koul <vinod.koul@intel.com>
Mon, 4 Apr 2016 16:41:43 +0000 (09:41 -0700)
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")
Cc: stable@vger.kernel.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
drivers/dma/hsu/hsu.c

index c7643e022578d022cc01a284ff988166728ce20d..b3b212146620f7e439cadb5b373ef293d8a5a0d5 100644 (file)
@@ -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);