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dmaengine: rcar-dmac: Fix residue reporting for pending descriptors

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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@linux-m68k.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[geert: Also check desc.active list]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Laurent Pinchart 2016-06-30 17:15:18 +02:00 committed by Vinod Koul
parent 48c73659ab
commit 55bd582b4d
1 changed files with 29 additions and 2 deletions
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31
drivers/dma/sh/rcar-dmac.c
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@ -1145,19 +1145,46 @@ 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