From d3183447ef561efe7e734cb4bc331519c276a786 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Wed, 29 Jun 2016 17:08:39 +0100 Subject: [PATCH] dmaengine: tegra-apb: Return the actual descriptor status 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 Signed-off-by: Vinod Koul --- 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 a8de08b8cbce..9d70b3aeb782 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); -- 2.20.1