Hi Andy, On 6/15/2017 1:29 AM, Andy Gross 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.
Agree, that part needs fixing in the original code. Also patch #10 changing the behavior to acknowledge the interrupts only when its spurious does not look correct. Trying to fix the original should simplify or avoid the spurious case itself. Regards, Sricharan -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
