[RFC 4/6] dmaengine: xilinx_dma: Freeup active list based on descriptor completion bit

[Radhey Shyam Pandey]

AXIDMA IP sets completion bit to 1 when the transfer is completed. Read
this bit to move descriptor from active list to the done list. This feature
is needed when interrupt delay timeout and IRQThreshold is enabled i.e
Dly_IrqEn is triggered w/o completing Interrupt Threshold.

Signed-off-by: Radhey Shyam Pandey <radheys at xilinx.com>
---
 drivers/dma/xilinx/xilinx_dma.c |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index 36e1ab9..518465e 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c
@@ -103,6 +103,7 @@
 #define XILINX_DMA_PARK_PTR_RD_REF_SHIFT	0
 #define XILINX_DMA_PARK_PTR_RD_REF_MASK		GENMASK(4, 0)
 #define XILINX_DMA_REG_VDMA_VERSION		0x002c
+#define XILINX_DMA_COMP_MASK			BIT(31)
 
 /* Register Direct Mode Registers */
 #define XILINX_DMA_REG_VSIZE			0x0000
@@ -1387,16 +1388,25 @@ static void xilinx_dma_issue_pending(struct dma_chan *dchan)
 static void xilinx_dma_complete_descriptor(struct xilinx_dma_chan *chan)
 {
 	struct xilinx_dma_tx_descriptor *desc, *next;
+	struct xilinx_axidma_tx_segment *seg;
 
 	/* This function was invoked with lock held */
 	if (list_empty(&chan->active_list))
 		return;
 
 	list_for_each_entry_safe(desc, next, &chan->active_list, node) {
-		list_del(&desc->node);
-		if (!desc->cyclic)
-			dma_cookie_complete(&desc->async_tx);
-		list_add_tail(&desc->node, &chan->done_list);
+
+		seg = list_last_entry(&desc->segments,
+				      struct xilinx_axidma_tx_segment, node);
+		if ((seg->hw.status & XILINX_DMA_COMP_MASK) ||
+			(!chan->xdev->has_axieth_connected)) {
+			list_del(&desc->node);
+			if (!desc->cyclic)
+				dma_cookie_complete(&desc->async_tx);
+			list_add_tail(&desc->node, &chan->done_list);
+		} else {
+			break;
+		}
 	}
 }
 
-- 
1.7.1