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Subject[PATCH AUTOSEL 4.14 8/9] spi: fsl-espi: Only process interrupts for expected events
Date
From: Chris Packham <chris.packham@alliedtelesis.co.nz>

[ Upstream commit b867eef4cf548cd9541225aadcdcee644669b9e1 ]

The SPIE register contains counts for the TX FIFO so any time the irq
handler was invoked we would attempt to process the RX/TX fifos. Use the
SPIM value to mask the events so that we only process interrupts that
were expected.

This was a latent issue exposed by commit 3282a3da25bd ("powerpc/64:
Implement soft interrupt replay in C").

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20200904002812.7300-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-fsl-espi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index 1d332e23f6ede..6a39ba5840c2e 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -556,13 +556,14 @@ static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
{
struct fsl_espi *espi = context_data;
- u32 events;
+ u32 events, mask;

spin_lock(&espi->lock);

/* Get interrupt events(tx/rx) */
events = fsl_espi_read_reg(espi, ESPI_SPIE);
- if (!events) {
+ mask = fsl_espi_read_reg(espi, ESPI_SPIM);
+ if (!(events & mask)) {
spin_unlock(&espi->lock);
return IRQ_NONE;
}
--
2.25.1
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