dmaengine: idxd: Fix clobbering of SWERR overflow bit on writeback

Current code blindly writes over the SWERR and the OVERFLOW bits. Write
back the bits actually read instead so the driver avoids clobbering the
OVERFLOW bit that comes after the register is read.

Fixes: bfe1d56091c1 ("dmaengine: idxd: Init and probe for Intel data accelerators")
Reported-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161352082229.3511254.1002151220537623503.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index a60ca11a5784a9c5dd0d55e4145868c13845d3a8..f1463fc581125adf61e82e9b5042333779b585d8 100644 (file)
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -124,7 +124,9 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
                for (i = 0; i < 4; i++)
                        idxd->sw_err.bits[i] = ioread64(idxd->reg_base +
                                        IDXD_SWERR_OFFSET + i * sizeof(u64));
-               iowrite64(IDXD_SWERR_ACK, idxd->reg_base + IDXD_SWERR_OFFSET);
+
+               iowrite64(idxd->sw_err.bits[0] & IDXD_SWERR_ACK,
+                         idxd->reg_base + IDXD_SWERR_OFFSET);
 
                if (idxd->sw_err.valid && idxd->sw_err.wq_idx_valid) {
                        int id = idxd->sw_err.wq_idx;