On Wed, Jun 14, 2017 at 12:57:25PM +0530, Sricharan R wrote: > Hi Varada, > > On 6/14/2017 11:22 AM, Varadarajan Narayanan wrote: > > It's possible for a SPI transaction to complete and get another > > interrupt and have it processed on the same spi_transfer before the > > transfer_one can set it to NULL. > > > > This masks unexpected interrupts, so let's set the spi_transfer to > > NULL in the interrupt once the transaction is done. So we can > > properly detect these bad interrupts and print warning messages. > > > > Signed-off-by: Matthew McClintock <mmccl...@codeaurora.org> > > Signed-off-by: Varadarajan Narayanan <var...@codeaurora.org> > > --- > > drivers/spi/spi-qup.c | 20 +++++++++++--------- > > 1 file changed, 11 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c > > index bd53e82..1a2a9d9 100644 > > --- a/drivers/spi/spi-qup.c > > +++ b/drivers/spi/spi-qup.c > > @@ -496,13 +496,13 @@ static irqreturn_t spi_qup_qup_irq(int irq, void > > *dev_id) > > struct spi_qup *controller = dev_id; > > struct spi_transfer *xfer; > > u32 opflags, qup_err, spi_err; > > - unsigned long flags; > > int error = 0; > > + bool done = 0; > > > > - spin_lock_irqsave(&controller->lock, flags); > > + spin_lock(&controller->lock); > > xfer = controller->xfer; > > controller->xfer = NULL; > > - spin_unlock_irqrestore(&controller->lock, flags); > > + spin_unlock(&controller->lock); > > Why change the locking here ? > > > > > qup_err = readl_relaxed(controller->base + QUP_ERROR_FLAGS); > > spi_err = readl_relaxed(controller->base + SPI_ERROR_FLAGS); > > @@ -556,16 +556,19 @@ static irqreturn_t spi_qup_qup_irq(int irq, void > > *dev_id) > > spi_qup_write(controller, xfer); > > } > > > > - spin_lock_irqsave(&controller->lock, flags); > > - controller->error = error; > > - controller->xfer = xfer; > > - spin_unlock_irqrestore(&controller->lock, flags); > > - > > /* re-read opflags as flags may have changed due to actions above */ > > opflags = readl_relaxed(controller->base + QUP_OPERATIONAL); > > > > if ((controller->rx_bytes == xfer->len && > > (opflags & QUP_OP_MAX_INPUT_DONE_FLAG)) || error) > > + done = true; > > + > > + spin_lock(&controller->lock); > > + controller->error = error; > > + controller->xfer = done ? NULL : xfer; > > + spin_unlock(&controller->lock); > > + > > + if (done) > > complete(&controller->done); > > > Its not clear, why the driver is setting the controller->xfer = NULL > and restoring it inside the irq. This patch seems to fix things on > top of that.
I think the original intent was to make sure that the irqhandler knew that there was no outstanding transaction. This begs the question of why that would ever be necessary. I think it would suffice to rework all of that to remove that behavior and perhaps enable/disable the irq as we need to during transactions. I've never been a fan of the controller->xfer being set to NULL. Regards, Andy
