From: Peng Fan peng.fan@nxp.com
commit 487ee861de176090b055eba5b252b56a3b9973d6 upstream.
The dmaengine_prep_slave_sg needs to use sg count returned by dma_map_sg, not use sport->dma_tx_nents, because the return value of dma_map_sg is not always same with "nents".
When enabling iommu for lpuart + edma, iommu framework may concatenate two sgs into one.
Fixes: 6250cc30c4c4e ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx") Cc: stable@vger.kernel.org Signed-off-by: Peng Fan peng.fan@nxp.com Link: https://lore.kernel.org/r/1572932977-17866-1-git-send-email-peng.fan@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/serial/fsl_lpuart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -436,8 +436,8 @@ static void lpuart_dma_tx(struct lpuart_ }
sport->dma_tx_desc = dmaengine_prep_slave_sg(sport->dma_tx_chan, sgl, - sport->dma_tx_nents, - DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); + ret, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT); if (!sport->dma_tx_desc) { dma_unmap_sg(dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); dev_err(dev, "Cannot prepare TX slave DMA!\n");