On 18.09.2017 13:08, Sylvain Lesne wrote:
Commit 6084fc2ec478 ("dmaengine: altera: Use macros instead of structs
to describe the registers") introduced a minus sign before a register
offset.
This leads to soft-locks of the DMA controller, since reading the last
status byte is required to pop the response from the FIFO. Failing to
do so will lead to a full FIFO, which means that the DMA controller
will stop processing descriptors.
Signed-off-by: Sylvain Lesne <lesne@xxxxxxxxxxx>
---
According to the datasheet, I think we also could drop the "bytes
transferred" read, since only the last byte of the status register has
the side effect of emptying the FIFO.
---
drivers/dma/altera-msgdma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index 32905d5606ac..35cbf2365f68 100644
--- a/drivers/dma/altera-msgdma.c
+++ b/drivers/dma/altera-msgdma.c
@@ -698,7 +698,7 @@ static void msgdma_tasklet(unsigned long data)
* bits. So we need to just drop these values.
*/
size = ioread32(mdev->resp + MSGDMA_RESP_BYTES_TRANSFERRED);
- status = ioread32(mdev->resp - MSGDMA_RESP_STATUS);
+ status = ioread32(mdev->resp + MSGDMA_RESP_STATUS);
msgdma_complete_descriptor(mdev);
msgdma_chan_desc_cleanup(mdev);
Thanks for spotting this:
Reviewed-by: Stefan Roese <sr@xxxxxxx>
Thanks,
Stefan
--
To unsubscribe from this list: send the line "unsubscribe dmaengine" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
