[PATCH] scsi: ufs: Consider device limitations for dma_mask

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Qualcomm SDM845 the capabilities of the UFS MEM controller states
that it's capable of dealing with 64 bit addresses, but DMA addresses
are truncated causing IOMMU faults when trying to issue operations.

Limit the DMA mask to that of the device, so that DMA allocations
is limited to the range supported by the bus and device and not just
following what the controller's capabilities states.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 drivers/scsi/ufs/ufshcd.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 9ba7671b84f8..dc0eb59dd46f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8151,11 +8151,14 @@ EXPORT_SYMBOL_GPL(ufshcd_dealloc_host);
  */
 static int ufshcd_set_dma_mask(struct ufs_hba *hba)
 {
-	if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT) {
-		if (!dma_set_mask_and_coherent(hba->dev, DMA_BIT_MASK(64)))
-			return 0;
-	}
-	return dma_set_mask_and_coherent(hba->dev, DMA_BIT_MASK(32));
+	u64 dma_mask = dma_get_mask(hba->dev);
+
+	if (hba->capabilities & MASK_64_ADDRESSING_SUPPORT)
+		dma_mask &= DMA_BIT_MASK(64);
+	else
+		dma_mask &= DMA_BIT_MASK(32);
+
+	return dma_set_mask_and_coherent(hba->dev, dma_mask);
 }
 
 /**
-- 
2.18.0