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SubjectRE: [PATCH -next 7/8] dmaengine: xilinx_dma: Check for both idle and halted state in axidma stop_transfer
Date
> -----Original Message-----
> From: Vinod Koul <vkoul@kernel.org>
> Sent: Thursday, September 26, 2019 10:51 PM
> To: Radhey Shyam Pandey <radheys@xilinx.com>
> Cc: dan.j.williams@intel.com; Michal Simek <michals@xilinx.com>;
> nick.graumann@gmail.com; andrea.merello@gmail.com; Appana Durga
> Kedareswara Rao <appanad@xilinx.com>; mcgrof@kernel.org;
> dmaengine@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH -next 7/8] dmaengine: xilinx_dma: Check for both idle
> and halted state in axidma stop_transfer
>
> On 05-09-19, 22:07, Radhey Shyam Pandey wrote:
> > From: Nicholas Graumann <nick.graumann@gmail.com>
> >
> > When polling for a stopped transfer in AXI DMA mode, in some cases the
> > status of the channel may indicate IDLE instead of HALTED if the
> > channel was reset due to an error.
> >
> > Signed-off-by: Nicholas Graumann <nick.graumann@gmail.com>
> > Signed-off-by: Radhey Shyam Pandey
> <radhey.shyam.pandey@xilinx.com>
> > ---
> > drivers/dma/xilinx/xilinx_dma.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/xilinx/xilinx_dma.c
> b/drivers/dma/xilinx/xilinx_dma.c
> > index b5dd62a..0896e07 100644
> > --- a/drivers/dma/xilinx/xilinx_dma.c
> > +++ b/drivers/dma/xilinx/xilinx_dma.c
> > @@ -1092,8 +1092,9 @@ static int xilinx_dma_stop_transfer(struct
> xilinx_dma_chan *chan)
> >
> > /* Wait for the hardware to halt */
> > return xilinx_dma_poll_timeout(chan, XILINX_DMA_REG_DMASR,
> val,
> > - val & XILINX_DMA_DMASR_HALTED, 0,
> > - XILINX_DMA_LOOP_COUNT);
> > + val | (XILINX_DMA_DMASR_IDLE |
> > + XILINX_DMA_DMASR_HALTED),
>
> The condition was bitwise AND and now is OR.. ??

Ah, it should be same as before . Only _IDLE mask should be in OR.

Also on second thought to this patch- we need to describe which error
scenario "in some cases the status of the channel may indicate IDLE
instead of HALTED" as mentioned in commit description.

@Nick: Can you comment?

>
> > + 0, XILINX_DMA_LOOP_COUNT);
> > }
> >
> > /**
> > --
> > 2.7.4
>
> --
> ~Vinod

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