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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        Vinod Koul <vkoul@kernel.org>
Subject: [PATCH 5.4 111/129] dmaengine: dw-edma: Fix scatter-gather address calculation
Date:   Tue,  8 Sep 2020 17:25:52 +0200
Message-Id: <20200908152235.387749205@linuxfoundation.org>
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From: Gustavo Pimentel <Gustavo.Pimentel@synopsys.com>

commit 05655541c9503bfd01af4e6cbd7f5a29ac748e6c upstream.

Fix the source and destination physical address calculation of a
peripheral device on scatter-gather implementation.

This issue manifested during tests using a 64 bits architecture system.
The abnormal behavior wasn't visible before due to all previous tests
were done using 32 bits architecture system, that masked his effect.

Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/8d3ab7e2ba96563fe3495b32f60077fffb85307d.1597327623.git.gustavo.pimentel@synopsys.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/dma/dw-edma/dw-edma-core.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -391,7 +391,7 @@ dw_edma_device_transfer(struct dw_edma_t
 			if (xfer->cyclic) {
 				burst->dar = xfer->xfer.cyclic.paddr;
 			} else {
-				burst->dar = sg_dma_address(sg);
+				burst->dar = dst_addr;
 				/* Unlike the typical assumption by other
 				 * drivers/IPs the peripheral memory isn't
 				 * a FIFO memory, in this case, it's a
@@ -399,14 +399,13 @@ dw_edma_device_transfer(struct dw_edma_t
 				 * and destination addresses are increased
 				 * by the same portion (data length)
 				 */
-				src_addr += sg_dma_len(sg);
 			}
 		} else {
 			burst->dar = dst_addr;
 			if (xfer->cyclic) {
 				burst->sar = xfer->xfer.cyclic.paddr;
 			} else {
-				burst->sar = sg_dma_address(sg);
+				burst->sar = src_addr;
 				/* Unlike the typical assumption by other
 				 * drivers/IPs the peripheral memory isn't
 				 * a FIFO memory, in this case, it's a
@@ -414,12 +413,14 @@ dw_edma_device_transfer(struct dw_edma_t
 				 * and destination addresses are increased
 				 * by the same portion (data length)
 				 */
-				dst_addr += sg_dma_len(sg);
 			}
 		}
 
-		if (!xfer->cyclic)
+		if (!xfer->cyclic) {
+			src_addr += sg_dma_len(sg);
+			dst_addr += sg_dma_len(sg);
 			sg = sg_next(sg);
+		}
 	}
 
 	return vchan_tx_prep(&chan->vc, &desc->vd, xfer->flags);