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Re: [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling

From Andy Gross <andy.gross@linaro.org>
Newsgroups linux.kernel
Subject Re: [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling
Date 2017-06-14 22:10 +0200
Message-ID <tSmM1-1fI-21@gated-at.bofh.it> (permalink)
References <tS9vs-1dT-7@gated-at.bofh.it> <tS9vw-1dT-49@gated-at.bofh.it> <tSaUx-2dU-3@gated-at.bofh.it>
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On Wed, Jun 14, 2017 at 12:51:11PM +0530, Sricharan R wrote:
> Hi Varada,
> 
> On 6/14/2017 11:22 AM, Varadarajan Narayanan wrote:
> > This is needed for v1, where the i/o completion is not
> > handled in the dma driver.
> > 
> > Signed-off-by: Andy Gross <andy.gross@linaro.org>
> > Signed-off-by: Varadarajan Narayanan <varada@codeaurora.org>
> > ---
> >  drivers/spi/spi-qup.c | 15 +++++++++++++--
> >  1 file changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
> > index 872de28..bd53e82 100644
> > --- a/drivers/spi/spi-qup.c
> > +++ b/drivers/spi/spi-qup.c
> > @@ -510,9 +510,9 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
> >  
> >  	writel_relaxed(qup_err, controller->base + QUP_ERROR_FLAGS);
> >  	writel_relaxed(spi_err, controller->base + SPI_ERROR_FLAGS);
> > -	writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);
> >  
> >  	if (!xfer) {
> > +		writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);
> 
>  This does look correct to remove acknowledging the QUP in normal case and
>   do it conditionally only when xfer = NULL.

This is to probably mask the issue of getting erroneous/spurious IRQs.

> 
> >  		dev_err_ratelimited(controller->dev, "unexpected irq %08x %08x %08x\n",
> >  				    qup_err, spi_err, opflags);
> >  		return IRQ_HANDLED;
> > @@ -540,7 +540,15 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
> >  		error = -EIO;
> >  	}
> >  
> > -	if (!spi_qup_is_dma_xfer(controller->mode)) {
> > +	if (spi_qup_is_dma_xfer(controller->mode)) {
> > +		writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);
> > +		if (opflags & QUP_OP_IN_SERVICE_FLAG &&
> > +		    opflags & QUP_OP_MAX_INPUT_DONE_FLAG)
> > +			complete(&controller->rxc);
> > +		if (opflags & QUP_OP_OUT_SERVICE_FLAG &&
> > +		    opflags & QUP_OP_MAX_OUTPUT_DONE_FLAG)
> > +			complete(&controller->txc);
> > +	} else {
> 
>  Is this because in patch #8 that we do not populate the dma callback
>  for v1. If that is done, this should not be required at all, as the
>  complete would be signalled from the dma callback.

I believe that is true.  There shouldn't be any IRQs for DMA enabled
transactions (at least BAM-dma).

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Thread

[PATCH 00/18] spi: qup: Fixes and add support for >64k transfers Varadarajan Narayanan <varada@codeaurora.org> - 2017-06-14 08:00 +0200
  [PATCH 15/18] spi: qup: refactor spi_qup_prep_sg Varadarajan Narayanan <varada@codeaurora.org> - 2017-06-14 08:00 +0200
  [PATCH 01/18] spi: qup: Enable chip select support Varadarajan Narayanan <varada@codeaurora.org> - 2017-06-14 08:00 +0200
    Re: [PATCH 01/18] spi: qup: Enable chip select support Stanimir Varbanov <stanimir.varbanov@linaro.org> - 2017-06-14 11:50 +0200
  [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling Varadarajan Narayanan <varada@codeaurora.org> - 2017-06-14 08:00 +0200
    Re: [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling Sricharan R <sricharan@codeaurora.org> - 2017-06-14 09:30 +0200
      Re: [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling Andy Gross <andy.gross@linaro.org> - 2017-06-14 22:10 +0200
        Re: [PATCH 10/18] spi: qup: Fix DMA mode interrupt handling Sricharan R <sricharan@codeaurora.org> - 2017-06-15 08:00 +0200

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