[PATCH v4 08/23] dmaengine: ste_dma40: Return IRQ_NONE without interrupt status

[Linus Walleij <linusw@kernel.org>]

d40_handle_interrupt() returns IRQ_HANDLED even when it does not find and
acknowledge an interrupt belonging to a registered DMA40 channel. If the
interrupt line remains asserted without any matching status bit, reporting
it as handled prevents the generic interrupt code from detecting the
stuck interrupt.

Track whether the handler acknowledges an interrupt and return IRQ_NONE
otherwise, allowing the generic spurious interrupt detector to disable a
faulty interrupt line.

Fixes: 8d318a50b3d7 ("DMAENGINE: Support for ST-Ericssons DMA40 block v3")
Assisted-by: LLM
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
 drivers/dma/ste_dma40.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 633f6a04fdc1..9f725369721b 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1790,6 +1790,7 @@ static void dma_tasklet(struct tasklet_struct *t)
 
 static irqreturn_t d40_handle_interrupt(int irq, void *data)
 {
+	irqreturn_t handled = IRQ_NONE;
 	int i;
 	u32 idx;
 	u32 row;
@@ -1838,6 +1839,7 @@ static irqreturn_t d40_handle_interrupt(int irq, void *data)
 
 		/* ACK interrupt */
 		writel(BIT(idx), base->virtbase + il[row].clr);
+		handled = IRQ_HANDLED;
 
 		spin_lock(&d40c->lock);
 
@@ -1855,7 +1857,7 @@ static irqreturn_t d40_handle_interrupt(int irq, void *data)
 	if (ret > 0)
 		pm_runtime_put_autosuspend(base->dev);
 
-	return IRQ_HANDLED;
+	return handled;
 }
 
 static int d40_validate_conf(struct d40_chan *d40c,

-- 
2.55.0