On 2025-08-23 4:39 pm, Jisheng Zhang wrote:
> If dma_cookie_status() returns DMA_COMPLETE, we can return immediately.
>
> From another side, the txstate is an optional parameter used to get a
> struct with auxilary transfer status information. When not provided
> the call to device_tx_status() should return the status of the dma
> cookie. Return the status of dma cookie when the txstate optional
> parameter is not provided.
Again, the current code was definitely intentional - I think this was
down to the hardware error case, where for reasons I now can't remember
I still had to nominally complete the aborted descriptor from the IRQ
handler to avoid causing some worse problem, and hence we don't return
early without cross-checking dch->status here, because returning
DMA_COMPLETE when the descriptor hasn't done its job makes dmatest unhappy.
I did spend a *lot* of time exercising all the error cases, and trying
to get a sensible result across all of the different reporting APIs was
fiddly to say the least - there's a huge lack of consistency between
drivers in this regard, and this was just my attempt to be the
least-worst one :)
Thanks,
Robin.
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
> drivers/dma/arm-dma350.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/dma/arm-dma350.c b/drivers/dma/arm-dma350.c
> index 96350d15ed85..17af9bb2a18f 100644
> --- a/drivers/dma/arm-dma350.c
> +++ b/drivers/dma/arm-dma350.c
> @@ -377,6 +377,8 @@ static enum dma_status d350_tx_status(struct dma_chan *chan, dma_cookie_t cookie
> u32 residue = 0;
>
> status = dma_cookie_status(chan, cookie, state);
> + if (status == DMA_COMPLETE || !state)
> + return status;
>
> spin_lock_irqsave(&dch->vc.lock, flags);
> if (cookie == dch->cookie) {