dmaengine: mmp_tdma: Validate the transfer direction

We only support DMA_DEV_TO_MEM and DMA_MEM_TO_DEV. Let's not do
undefined things with other values and reject them.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200424215020.105281-1-lkundrak@v3.sk
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c
index 2e318558c644667008ef16e355510b29d3d26c65..42f8b2fb7684ef548158830c7849bf711dda2594 100644 (file)
--- a/drivers/dma/mmp_tdma.c
+++ b/drivers/dma/mmp_tdma.c
@@ -427,6 +427,11 @@ static struct dma_async_tx_descriptor *mmp_tdma_prep_dma_cyclic(
        int num_periods = buf_len / period_len;
        int i = 0, buf = 0;
 
+       if (!is_slave_direction(direction)) {
+               dev_err(tdmac->dev, "unsupported transfer direction\n");
+               return NULL;
+       }
+
        if (tdmac->status != DMA_COMPLETE) {
                dev_err(tdmac->dev, "controller busy");
                return NULL;