dmaengine: dma-jz4780: Add missing residue DTC mask

The 'dtc' word in jz DMA descriptors contains two fields: The
lowest 24 bits are the transfer count, and upper 8 bits are the DOA
offset to next descriptor. The upper 8 bits are now correctly masked
off when computing residue in jz4780_dma_desc_residue(). Note that
reads of the DTCn hardware reg are automatically masked this way.

Signed-off-by: Daniel Silsby <dansilsby@gmail.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index 3a4d0a4..bd3cecb 100644 (file)
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -616,7 +616,8 @@ static size_t jz4780_dma_desc_residue(struct jz4780_dma_chan *jzchan,
        residue = 0;
 
        for (i = next_sg; i < desc->count; i++)
-               residue += desc->desc[i].dtc << jzchan->transfer_shift;
+               residue += (desc->desc[i].dtc & GENMASK(23, 0)) <<
+                       jzchan->transfer_shift;
 
        if (next_sg != 0) {
                count = jz4780_dma_chn_readl(jzdma, jzchan->id,