[PATCH 09/11] dmaengine: dw-axi-dmac: try best to get residue when tx is running

[Jisheng Zhang <jszhang@xxxxxxxxxx>]

When tx is running, vchan_find_desc() will return NULL, try our best
to get the residue in this case.

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index a6e46cb66000..1c1b9574985a 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -305,6 +305,7 @@ dma_chan_tx_status(struct dma_chan *dchan, dma_cookie_t cookie,
 		  struct dma_tx_state *txstate)
 {
 	struct axi_dma_chan *chan = dchan_to_axi_dma_chan(dchan);
+	struct axi_dma_desc *desc = NULL;
 	struct virt_dma_desc *vdesc;
 	enum dma_status status;
 	u32 completed_length;
@@ -322,9 +323,15 @@ dma_chan_tx_status(struct dma_chan *dchan, dma_cookie_t cookie,
 
 	vdesc = vchan_find_desc(&chan->vc, cookie);
 	if (vdesc) {
-		length = vd_to_axi_desc(vdesc)->length;
-		completed_blocks = vd_to_axi_desc(vdesc)->completed_blocks;
-		len = vd_to_axi_desc(vdesc)->hw_desc[0].len;
+		desc = vd_to_axi_desc(vdesc);
+	} else if (chan->desc && chan->desc->vd.tx.cookie == cookie) {
+		desc = chan->desc;
+	}
+
+	if (desc) {
+		length = desc->length;
+		completed_blocks = desc->completed_blocks;
+		len = desc->hw_desc[0].len;
 		completed_length = completed_blocks * len;
 		bytes = length - completed_length;
 	}
@@ -425,6 +432,7 @@ static void axi_chan_block_xfer_start(struct axi_dma_chan *chan,
 	axi_chan_irq_set(chan, irq_mask);
 
 	axi_chan_enable(chan);
+	chan->desc = first;
 }
 
 static void axi_chan_start_first_queued(struct axi_dma_chan *chan)
@@ -1188,6 +1196,7 @@ static int dma_chan_terminate_all(struct dma_chan *dchan)
 	spin_unlock_irqrestore(&chan->vc.lock, flags);
 
 	vchan_dma_desc_free_list(&chan->vc, &head);
+	chan->desc = NULL;
 
 	dev_vdbg(dchan2dev(dchan), "terminated: %s\n", axi_chan_name(chan));
 
-- 
2.39.2