diff mbox series

[v3,3/6] dmaengine: dw-edma: Fix programming the source & dest addresses for ep

Message ID 20220307224750.18055-3-Frank.Li@nxp.com (mailing list archive)
State Changes Requested
Headers show
Series [v3,1/6] dmaengine: dw-edma: fix dw_edma_probe() can't be call globally | expand

Commit Message

Frank Li March 7, 2022, 10:47 p.m. UTC 
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

When eDMA is controlled by the Endpoint (EP), the current logic incorrectly
programs the source and destination addresses for read and write. Since the
Root complex and Endpoint uses the opposite channels for read/write, fix the
issue by finding out the read operation first and program the eDMA accordingly.

Cc: stable@vger.kernel.org
Fixes: bd96f1b2f43a ("dmaengine: dw-edma: support local dma device transfer semantics")
Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
Resend added dmaengine@vger.kernel.org

Change from V1-v3
 - Direct pick up from Manivannan

 drivers/dma/dw-edma/dw-edma-core.c | 32 +++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 0cb66434f9e14..3636c48f5df15 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -334,6 +334,7 @@  dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 	struct dw_edma_chunk *chunk;
 	struct dw_edma_burst *burst;
 	struct dw_edma_desc *desc;
+	bool read = false;
 	u32 cnt = 0;
 	int i;
 
@@ -424,7 +425,36 @@  dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		chunk->ll_region.sz += burst->sz;
 		desc->alloc_sz += burst->sz;
 
-		if (chan->dir == EDMA_DIR_WRITE) {
+		/****************************************************************
+		 *
+		 *        Root Complex                           Endpoint
+		 * +-----------------------+             +----------------------+
+		 * |                       |    TX CH    |                      |
+		 * |                       |             |                      |
+		 * |      DEV_TO_MEM       <-------------+     MEM_TO_DEV       |
+		 * |                       |             |                      |
+		 * |                       |             |                      |
+		 * |      MEM_TO_DEV       +------------->     DEV_TO_MEM       |
+		 * |                       |             |                      |
+		 * |                       |    RX CH    |                      |
+		 * +-----------------------+             +----------------------+
+		 *
+		 * If eDMA is controlled by the Root complex, TX channel
+		 * (EDMA_DIR_WRITE) is used for memory read (DEV_TO_MEM) and RX
+		 * channel (EDMA_DIR_READ) is used for memory write (MEM_TO_DEV).
+		 *
+		 * If eDMA is controlled by the endpoint, RX channel
+		 * (EDMA_DIR_READ) is used for memory read (DEV_TO_MEM) and TX
+		 * channel (EDMA_DIR_WRITE) is used for memory write (MEM_TO_DEV).
+		 *
+		 ****************************************************************/
+
+		if ((dir == DMA_DEV_TO_MEM && chan->dir == EDMA_DIR_READ) ||
+		    (dir == DMA_DEV_TO_MEM && chan->dir == EDMA_DIR_WRITE))
+			read = true;
+
+		/* Program the source and destination addresses for DMA read/write */
+		if (read) {
 			burst->sar = src_addr;
 			if (xfer->type == EDMA_XFER_CYCLIC) {
 				burst->dar = xfer->xfer.cyclic.paddr;