[PATCH net] net: dsa: mv88e6xxx: fix lockup on warm boot

[PATCH net] net: dsa: mv88e6xxx: fix lockup on warm boot

[Russell King]

If the switch is not hardware reset on a warm boot, interrupts can be
left enabled, and possibly pending. This will cause us to enter an
infinite loop trying to service an interrupt we are unable to handle,
thereby preventing the kernel from booting.

Ensure that the global 2 interrupt sources are disabled before we claim
the parent interrupt.

Observed on the ZII development revision B and C platforms with
reworked serdes support, and using reboot -f to reboot the platform.

Fixes: dc30c35be720 ("net: dsa: mv88e6xxx: Implement interrupt support.")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/dsa/mv88e6xxx/global2.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mv88e6xxx/global2.c b/drivers/net/dsa/mv88e6xxx/global2.c
index 01503014b1ee..8fd483020c5b 100644
--- a/drivers/net/dsa/mv88e6xxx/global2.c
+++ b/drivers/net/dsa/mv88e6xxx/global2.c
@@ -1099,6 +1099,13 @@ int mv88e6xxx_g2_irq_setup(struct mv88e6xxx_chip *chip)
 {
 	int err, irq, virq;
 
+	chip->g2_irq.masked = ~0;
+	mv88e6xxx_reg_lock(chip);
+	err = mv88e6xxx_g2_int_mask(chip, ~chip->g2_irq.masked);
+	mv88e6xxx_reg_unlock(chip);
+	if (err)
+		return err;
+
 	chip->g2_irq.domain = irq_domain_add_simple(
 		chip->dev->of_node, 16, 0, &mv88e6xxx_g2_irq_domain_ops, chip);
 	if (!chip->g2_irq.domain)
@@ -1108,7 +1115,6 @@ int mv88e6xxx_g2_irq_setup(struct mv88e6xxx_chip *chip)
 		irq_create_mapping(chip->g2_irq.domain, irq);
 
 	chip->g2_irq.chip = mv88e6xxx_g2_irq_chip;
-	chip->g2_irq.masked = ~0;
 
 	chip->device_irq = irq_find_mapping(chip->g1_irq.domain,
 					    MV88E6XXX_G1_STS_IRQ_DEVICE);
-- 
2.20.1

Re: [PATCH net] net: dsa: mv88e6xxx: fix lockup on warm boot

[Andrew Lunn]

On Fri, Feb 28, 2020 at 07:39:41PM +0000, Russell King wrote:
> If the switch is not hardware reset on a warm boot, interrupts can be
> left enabled, and possibly pending. This will cause us to enter an
> infinite loop trying to service an interrupt we are unable to handle,
> thereby preventing the kernel from booting.
> 
> Ensure that the global 2 interrupt sources are disabled before we claim
> the parent interrupt.
> 
> Observed on the ZII development revision B and C platforms with
> reworked serdes support, and using reboot -f to reboot the platform.
> 
> Fixes: dc30c35be720 ("net: dsa: mv88e6xxx: Implement interrupt support.")
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH net] net: dsa: mv88e6xxx: fix lockup on warm boot

[David Miller]

From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Fri, 28 Feb 2020 19:39:41 +0000

> If the switch is not hardware reset on a warm boot, interrupts can be
> left enabled, and possibly pending. This will cause us to enter an
> infinite loop trying to service an interrupt we are unable to handle,
> thereby preventing the kernel from booting.
> 
> Ensure that the global 2 interrupt sources are disabled before we claim
> the parent interrupt.
> 
> Observed on the ZII development revision B and C platforms with
> reworked serdes support, and using reboot -f to reboot the platform.
> 
> Fixes: dc30c35be720 ("net: dsa: mv88e6xxx: Implement interrupt support.")
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

Applied and queued up for -stable, thanks.