Commit 71f7e6cc5500 ('dmaengine: tegra20-apb-dma: Only calculate residue
if txstate exists') changed the tegra_dma_tx_status() function to only
calculate the residue if there is a valid 'txstate' pointer for storing
the residue. Although this makes sense, this changed the behaviour of
the function tegra_dma_tx_status() such that if the pointer 'txstate' is
not valid, then we will return whatever state is returned by
dma_cookie_status() and no longer return the state by looking up the DMA
descriptor and returning it's state.
Please note that dma_cookie_status() will either return DMA_COMPLETE or
DMA_IN_PROGRESS. However, if dma_cookie_status() returns DMA_IN_PROGRESS
the actual status could be DMA_ERROR which will only be seen from
checking the descriptor status. Therefore, even if 'txstate' is not
valid, still check to see if there is a valid descriptor for the cookie
in question and if so return the descriptor state. Finally, ensure the
residue is still not calculated if the 'txstate' is not valid.
Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
---
drivers/dma/tegra20-apb-dma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 6da9e1032236..6ab9eb98588a 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -811,7 +811,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
unsigned int residual;
ret = dma_cookie_status(dc, cookie, txstate);
- if (ret == DMA_COMPLETE || !txstate)
+ if (ret == DMA_COMPLETE)
return ret;
spin_lock_irqsave(&tdc->lock, flags);
@@ -837,7 +837,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
dma_desc = NULL;
found:
- if (dma_desc) {
+ if (dma_desc && txstate) {
residual = dma_desc->bytes_requested -
(dma_desc->bytes_transferred %
dma_desc->bytes_requested);
--
2.1.4
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