Messages in this thread Patch in this message | | | From | Stephen Barber <> | Subject | [PATCH] dmaengine: pl330: fix residual for non-running BUSY descriptors | Date | Thu, 18 Aug 2016 17:59:59 -0700 |
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Only one descriptor in the work list should be running at any given time, but it's possible to have an enqueued BUSY descriptor that has not yet transferred any data, or for a BUSY descriptor to linger briefly before transitioning to DONE. These cases should be handled to keep residual calculations consistent even with the non-running BUSY descriptors in the work list.
Signed-off-by: Stephen Barber <smbarber@chromium.org> --- drivers/dma/pl330.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 372b435..ff8f889 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2274,7 +2274,7 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, { enum dma_status ret; unsigned long flags; - struct dma_pl330_desc *desc, *running = NULL; + struct dma_pl330_desc *desc, *running = NULL, *last_enq = NULL; struct dma_pl330_chan *pch = to_pchan(chan); unsigned int transferred, residual = 0; @@ -2291,6 +2291,8 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, if (pch->thread->req_running != -1) running = pch->thread->req[pch->thread->req_running].desc; + last_enq = pch->thread->req[pch->thread->lstenq].desc; + /* Check in pending list */ list_for_each_entry(desc, &pch->work_list, node) { if (desc->status == DONE) @@ -2298,6 +2300,15 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie, else if (running && desc == running) transferred = pl330_get_current_xferred_count(pch, desc); + else if (desc->status == BUSY) + /* + * Busy but not running means either just enqueued, + * or finished and not yet marked done + */ + if (desc == last_enq) + transferred = 0; + else + transferred = desc->bytes_requested; else transferred = 0; residual += desc->bytes_requested - transferred; -- 2.8.0.rc3.226.g39d4020
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