[PATCH v4 03/24] dmaengine: dw-edma: Factor out linked-list transfer start

Koichiro Den <[email protected]> Wed, 29 Jul 2026 23:30:15 +0900
Newsgroups org.kernel.vger.dmaengine,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
Move linked-list programming into dw_edma_core_ll_start(). It can derive
the first-batch state from desc->start_burst, so dw_edma_core_start() no
longer needs a pass-through argument.

No functional change.

Reviewed-by: Frank Li <[email protected]>
Signed-off-by: Koichiro Den <[email protected]>
---
Changes in v4:
  - No changes.

 drivers/dma/dw-edma/dw-edma-core.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 1f893dc54c79..6a25a050b89c 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -67,17 +67,11 @@ static void vchan_free_desc(struct virt_dma_desc *vdesc)
 	kfree(vd2dw_edma_desc(vdesc));
 }
 
-static void dw_edma_core_start(struct dw_edma_desc *desc, bool first)
+static void dw_edma_core_ll_start(struct dw_edma_desc *desc)
 {
 	struct dw_edma_chan *chan = desc->chan;
-	size_t i = 0;
-
-	if (chan->non_ll) {
-		chan->dw->core->non_ll_start(chan, &desc->burst[desc->start_burst]);
-		desc->done_burst = desc->start_burst;
-		desc->start_burst += 1;
-		return;
-	}
+	size_t i;
+	bool first = !desc->start_burst;
 
 	for (i = 0; i + desc->start_burst < desc->nburst; i++) {
 		u32 idx = i + desc->start_burst;
@@ -101,6 +95,21 @@ static void dw_edma_core_start(struct dw_edma_desc *desc, bool first)
 	dw_edma_core_ch_doorbell(chan);
 }
 
+static void dw_edma_core_start(struct dw_edma_desc *desc)
+{
+	struct dw_edma_chan *chan = desc->chan;
+
+	if (chan->non_ll) {
+		chan->dw->core->non_ll_start(chan,
+					     &desc->burst[desc->start_burst]);
+		desc->done_burst = desc->start_burst;
+		desc->start_burst += 1;
+		return;
+	}
+
+	dw_edma_core_ll_start(desc);
+}
+
 static int dw_edma_start_transfer(struct dw_edma_chan *chan)
 {
 	struct dw_edma_desc *desc;
@@ -114,7 +123,7 @@ static int dw_edma_start_transfer(struct dw_edma_chan *chan)
 	if (!desc)
 		return 0;
 
-	dw_edma_core_start(desc, !desc->start_burst);
+	dw_edma_core_start(desc);
 
 	desc->cb = !desc->cb;
 
-- 
2.51.0