[PATCH 4.2 057/258] dmaengine: at_xdmac: fix bug in prep_dma_cyclic

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>

commit e900c30dc1bb0cbc07708e9be1188f531632b2ef upstream.

In cyclic mode, the round chaining has been broken by the introduction
of at_xdmac_queue_desc(): AT_XDMAC_MBR_UBC_NDE is set for all descriptors
excepted for the last one. at_xdmac_queue_desc() has to be called one
more time to chain the last and the first descriptors.

Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
Fixes: 0d0ee751f7f7 ("dmaengine: xdmac: Rework the chaining logic")
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/dma/at_xdmac.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -806,10 +806,7 @@ at_xdmac_prep_dma_cyclic(struct dma_chan
 		list_add_tail(&desc->desc_node, &first->descs_list);
 	}
 
-	prev->lld.mbr_nda = first->tx_dma_desc.phys;
-	dev_dbg(chan2dev(chan),
-		"%s: chain lld: prev=0x%p, mbr_nda=%pad\n",
-		__func__, prev, &prev->lld.mbr_nda);
+	at_xdmac_queue_desc(chan, prev, first);
 	first->tx_dma_desc.flags = flags;
 	first->xfer_size = buf_len;
 	first->direction = direction;


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