On Wed, Jun 14, 2017 at 2:59 PM, Andy Gross <andy.gr...@linaro.org> wrote: > 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.
Also, this patch presumably fixes an issue seen on Dakota SoCs, doesn't add or remote the NULL bits. -M
