dmaengine: dw-edma: Don't permit non-inc interleaved xfers

The DW eDMA controller always increments both source and destination
addresses. Permitting DMA interleaved transfers with no src_inc/dst_inc
flags set may lead to unexpected behaviour for the device users.

Terminate interleaved transfers if at least one of the
dma_interleaved_template.{src_inc,dst_inc} flag is initialized to "false".

Note that in addition, we need to increase the source and destination
addresses after each iteration.

Link: https://lore.kernel.org/r/20230113171409.30470-6-Sergey.Semin@baikalelectronics.ru
Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 778d91d9fc1b47ada1d684f8992e470969c9b905..35588e14f79a3ee026679414c47389a777a817db 100644 (file)
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -385,6 +385,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
                        return NULL;
                if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
                        return NULL;
+               if (!xfer->xfer.il->src_inc || !xfer->xfer.il->dst_inc)
+                       return NULL;
        } else {
                return NULL;
        }
@@ -484,15 +486,13 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
                        struct dma_interleaved_template *il = xfer->xfer.il;
                        struct data_chunk *dc = &il->sgl[i];
 
-                       if (il->src_sgl) {
-                               src_addr += burst->sz;
+                       src_addr += burst->sz;
+                       if (il->src_sgl)
                                src_addr += dmaengine_get_src_icg(il, dc);
-                       }
 
-                       if (il->dst_sgl) {
-                               dst_addr += burst->sz;
+                       dst_addr += burst->sz;
+                       if (il->dst_sgl)
                                dst_addr += dmaengine_get_dst_icg(il, dc);
-                       }
                }
        }