From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Cookies corresponding to pending transfers have a residue value equal to
the full size of the corresponding descriptor. The driver miscomputes
that and uses the size of the active descriptor instead. Fix it.
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
[geert: Also check desc.active list]
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 59951fb..86aef28 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1145,19 +1145,47 @@ static unsigned int rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan,
struct rcar_dmac_desc *desc = chan->desc.running;
struct rcar_dmac_xfer_chunk *running = NULL;
struct rcar_dmac_xfer_chunk *chunk;
+ enum dma_status status;
unsigned int residue = 0;
unsigned int dptr = 0;
if (!desc)
return 0;
+
+ /*
+ * If the cookie corresponds to a descriptor that has been completed
+ * there is no residue. The same check has already been performed by the
+ * caller but without holding the channel lock, so the descriptor could
+ * now be complete.
+ */
+ status = dma_cookie_status(&chan->chan, cookie, NULL);
+ if (status == DMA_COMPLETE)
+ return 0;
+
/*
* If the cookie doesn't correspond to the currently running transfer
* then the descriptor hasn't been processed yet, and the residue is
* equal to the full descriptor size.
*/
- if (cookie != desc->async_tx.cookie)
- return desc->size;
+ if (cookie != desc->async_tx.cookie) {
+ list_for_each_entry(desc, &chan->desc.pending, node) {
+ if (cookie == desc->async_tx.cookie)
+ return desc->size;
+ }
+ list_for_each_entry(desc, &chan->desc.active, node) {
+ if (cookie == desc->async_tx.cookie)
+ return desc->size;
+ }
+
+ /*
+ * No descriptor found for the cookie, there's thus no residue.
+ * This shouldn't happen if the calling driver passes a correct
+ * cookie value.
+ */
+ WARN(1, "No descriptor for cookie!");
+ return 0;
+ }
/*
* In descriptor mode the descriptor running pointer is not maintained
--
2.8.3
