On 02/02/2020 22:28, Dmitry Osipenko wrote:
> There is no harm in keeping DMA active in the case of error condition,
> which should never happen in practice anyways. This will become useful
> for the next patch, which will keep RPM enabled only during of DMA
> transfer, and thus, it will be much nicer if cyclic DMA handler could
> not touch the DMA-enable state.
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> drivers/dma/tegra20-apb-dma.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index c7dc27ef1856..50abce608318 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -571,9 +571,7 @@ static bool handle_continuous_head_request(struct tegra_dma_channel *tdc,
> */
> hsgreq = list_first_entry(&tdc->pending_sg_req, typeof(*hsgreq), node);
> if (!hsgreq->configured) {
> - tegra_dma_stop(tdc);
> - dev_err(tdc2dev(tdc), "Error in DMA transfer, aborting DMA\n");
> - tegra_dma_abort_all(tdc);
> + dev_err_ratelimited(tdc2dev(tdc), "Error in DMA transfer\n");
While we are at it, a more descriptive error message could be good here.
I believe that this condition would indicate a potential underrun condition.
> return false;
> }
>
> @@ -772,7 +770,10 @@ static int tegra_dma_terminate_all(struct dma_chan *dc)
> if (!list_empty(&tdc->pending_sg_req) && was_busy) {
> sgreq = list_first_entry(&tdc->pending_sg_req, typeof(*sgreq),
> node);
> - sgreq->dma_desc->bytes_transferred +=
> + dma_desc = sgreq->dma_desc;
> +
> + if (dma_desc->dma_status != DMA_ERROR)
> + dma_desc->bytes_transferred +=
> get_current_xferred_count(tdc, sgreq, wcount);
I am wondering if we need to check this here? I assume that the transfer
count would still reflect the amount of data transferred, even if some
was dropped. We will never know how much data was lost.
Jon
--
nvpublic
