[PATCH 11/18] spi: qup: properly detect extra interrupts

Varadarajan Narayanan
2017-06-14T05:54:03Z

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 <mmcclint@codeaurora.org>
Signed-off-by: Varadarajan Narayanan <varada@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);

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);

return IRQ_HANDLED;
@@ -765,7 +768,6 @@ static int spi_qup_transfer_one(struct spi_master *master,
exit:
spi_qup_set_state(controller, QUP_STATE_RESET);
spin_lock_irqsave(&controller->lock, flags);
- controller->xfer = NULL;
if (!ret)
ret = controller->error;
spin_unlock_irqrestore(&controller->lock, flags);