[PATCH 3.2 096/185] can: sja1000: fix {pre,post}_irq() handling and IRQ handler return value

Ben Hutchings
2013-12-29T02:42:09Z

From: Oliver Hartkopp <socketcan@hartkopp.net>

commit 2fea6cd303c0d0cd9067da31d873b6a6d5bd75e7 upstream.

This patch fixes the issue that the sja1000_interrupt() function may have
returned IRQ_NONE without processing the optional pre_irq() and post_irq()
function before. Further the irq processing counter 'n' is moved to the end of
the while statement to return correct IRQ_[NONE|HANDLED] values at error
conditions.

Reported-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
[bwh: Backported to 3.2: s/SJA1000_IER/REG_IER/; s/SJA1000_IR/REG_IR/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -488,19 +488,19 @@ irqreturn_t sja1000_interrupt(int irq, v
uint8_t isrc, status;
int n = 0;

- /* Shared interrupts and IRQ off? */
- if (priv->read_reg(priv, REG_IER) == IRQ_OFF)
- return IRQ_NONE;
-
if (priv->pre_irq)
priv->pre_irq(priv);

+ /* Shared interrupts and IRQ off? */
+ if (priv->read_reg(priv, REG_IER) == IRQ_OFF)
+ goto out;
+
while ((isrc = priv->read_reg(priv, REG_IR)) && (n < SJA1000_MAX_IRQ)) {
- n++;
+
status = priv->read_reg(priv, SJA1000_REG_SR);
/* check for absent controller due to hw unplug */
if (status == 0xFF && sja1000_is_absent(priv))
- return IRQ_NONE;
+ goto out;

if (isrc & IRQ_WUI)
dev_warn(dev->dev.parent, "wakeup interrupt\n");
@@ -519,7 +519,7 @@ irqreturn_t sja1000_interrupt(int irq, v
status = priv->read_reg(priv, SJA1000_REG_SR);
/* check for absent controller */
if (status == 0xFF && sja1000_is_absent(priv))
- return IRQ_NONE;
+ goto out;
}
}
if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {
@@ -527,8 +527,9 @@ irqreturn_t sja1000_interrupt(int irq, v
if (sja1000_err(dev, isrc, status))
break;
}
+ n++;
}
-
+out:
if (priv->post_irq)
priv->post_irq(priv);