[PATCH] dmaengine: altera-msgdma: fail probe when reset times out

[Pengpeng Hou]

msgdma_probe() resets the controller before publishing the DMA device
and OF DMA provider, but msgdma_reset() only logs a timeout and then
continues to enable the controller and mark it idle.

If the reset bit never clears, the driver can still register a DMA
engine backed by a controller that did not leave reset. Return the
readl_poll_timeout() error from msgdma_reset() and abort probe on reset
failure.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/dma/altera-msgdma.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index b46999c81df0..f60a4e86a246 100644
--- a/drivers/dma/altera-msgdma.c
+++ b/drivers/dma/altera-msgdma.c
@@ -466,7 +466,7 @@ static int msgdma_dma_config(struct dma_chan *dchan,
 	return 0;
 }
 
-static void msgdma_reset(struct msgdma_device *mdev)
+static int msgdma_reset(struct msgdma_device *mdev)
 {
 	u32 val;
 	int ret;
@@ -478,8 +478,10 @@ static void msgdma_reset(struct msgdma_device *mdev)
 	ret = readl_poll_timeout(mdev->csr + MSGDMA_CSR_STATUS, val,
 				 (val & MSGDMA_CSR_STAT_RESETTING) == 0,
 				 1, 10000);
-	if (ret)
+	if (ret) {
 		dev_err(mdev->dev, "DMA channel did not reset\n");
+		return ret;
+	}
 
 	/* Clear all status bits */
 	iowrite32(MSGDMA_CSR_STAT_MASK, mdev->csr + MSGDMA_CSR_STATUS);
@@ -489,6 +491,7 @@ static void msgdma_reset(struct msgdma_device *mdev)
 		  MSGDMA_CSR_CTL_GLOBAL_INTR, mdev->csr + MSGDMA_CSR_CONTROL);
 
 	mdev->idle = true;
+	return 0;
 };
 
 static void msgdma_copy_one(struct msgdma_device *mdev,
@@ -896,7 +899,9 @@ static int msgdma_probe(struct platform_device *pdev)
 		goto fail;
 	}
 
-	msgdma_reset(mdev);
+	ret = msgdma_reset(mdev);
+	if (ret)
+		goto fail;
 
 	ret = dma_async_device_register(dma_dev);
 	if (ret)
-- 
2.50.1 (Apple Git-155)