This Linux kernel change "dmaengine: sprd: Fix block length overflow" is included in the Linux 5.2 release. This change is authored by Eric Long <eric.long [at] unisoc.com> on Mon May 6 15:28:31 2019 +0800. The commit for this change in Linux stable tree is 89d03b3 (patch).
dmaengine: sprd: Fix block length overflow The maximum value of block length is 0xffff, so if the configured transfer length is more than 0xffff, that will cause block length overflow to lead a configuration error. Thus we can set block length as the maximum burst length to avoid this issue, since the maximum burst length will not be a big value which is more than 0xffff. Signed-off-by: Eric Long <firstname.lastname@example.org> Signed-off-by: Baolin Wang <email@example.com> Signed-off-by: Vinod Koul <firstname.lastname@example.org>
There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
drivers/dma/sprd-dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c index 0f92e60..a01c232 100644 --- a/drivers/dma/sprd-dma.c +++ b/drivers/dma/sprd-dma.c @@ -778,7 +778,7 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, temp |= slave_cfg->src_maxburst & SPRD_DMA_FRG_LEN_MASK; hw->frg_len = temp; - hw->blk_len = len & SPRD_DMA_BLK_LEN_MASK; + hw->blk_len = slave_cfg->src_maxburst & SPRD_DMA_BLK_LEN_MASK; hw->trsc_len = len & SPRD_DMA_TRSC_LEN_MASK; temp = (dst_step & SPRD_DMA_TRSF_STEP_MASK) << SPRD_DMA_DEST_TRSF_STEP_OFFSET;