diff mbox series

[9/9] dmaengine: dw-edma: eDMA: Fix possible race condition in local setup

Message ID 20230609081654.330857-10-kory.maincent@bootlin.com
State New
Headers
Series Fix support of dw-edma HDMA NATIVE IP in remote setup |

Commit Message

Köry Maincent June 9, 2023, 8:16 a.m. UTC 
  From: Kory Maincent <kory.maincent@bootlin.com>

When writing the linked list elements and pointer the control need to be
written at the end. If the control is written and the SAR and DAR not
stored we could face a race condition. Added a memory barrier to make sure
the memory has been written.

Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
---

This patch has not been tested since I don't have board with eDMA in local
setup.
---
 drivers/dma/dw-edma/dw-edma-v0-core.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index a5d921ef54ec..612c8c49668f 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -284,10 +284,13 @@  static void dw_edma_v0_write_ll_data(struct dw_edma_chunk *chunk, int i,
 	if (chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
 		struct dw_edma_v0_lli *lli = chunk->ll_region.vaddr.mem + ofs;
 
-		lli->control = control;
 		lli->transfer_size = size;
 		lli->sar.reg = sar;
 		lli->dar.reg = dar;
+
+		/* Make sure sar and dar is written before writing control */
+		dma_wmb();
+		lli->control = control;
 	} else {
 		struct dw_edma_v0_lli __iomem *lli = chunk->ll_region.vaddr.io + ofs;
 
@@ -306,8 +309,11 @@  static void dw_edma_v0_write_ll_link(struct dw_edma_chunk *chunk,
 	if (chunk->chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) {
 		struct dw_edma_v0_llp *llp = chunk->ll_region.vaddr.mem + ofs;
 
-		llp->control = control;
 		llp->llp.reg = pointer;
+
+		/* Make sure sar and dar is written before writing control */
+		dma_wmb();
+		llp->control = control;
 	} else {
 		struct dw_edma_v0_llp __iomem *llp = chunk->ll_region.vaddr.io + ofs;