diff options
authorJohn David Anglin <dave.anglin@bell.net>2019-02-11 13:40:21 -0500
committerDavid S. Miller <davem@davemloft.net>2019-02-13 20:46:38 -0800
commit7c0db24cc431e2196d98a5d5ddaa9088e2fcbfe5 (patch)
parentb79555d5d8d32643e9d7193341dcaff13bf9ffcd (diff)
dsa: mv88e6xxx: Ensure all pending interrupts are handled prior to exit
The GPIO interrupt controller on the espressobin board only supports edge interrupts. If one enables the use of hardware interrupts in the device tree for the 88E6341, it is possible to miss an edge. When this happens, the INTn pin on the Marvell switch is stuck low and no further interrupts occur. I found after adding debug statements to mv88e6xxx_g1_irq_thread_work() that there is a race in handling device interrupts (e.g. PHY link interrupts). Some interrupts are directly cleared by reading the Global 1 status register. However, the device interrupt flag, for example, is not cleared until all the unmasked SERDES and PHY ports are serviced. This is done by reading the relevant SERDES and PHY status register. The code only services interrupts whose status bit is set at the time of reading its status register. If an interrupt event occurs after its status is read and before all interrupts are serviced, then this event will not be serviced and the INTn output pin will remain low. This is not a problem with polling or level interrupts since the handler will be called again to process the event. However, it's a big problem when using level interrupts. The fix presented here is to add a loop around the code servicing switch interrupts. If any pending interrupts remain after the current set has been handled, we loop and process the new set. If there are no pending interrupts after servicing, we are sure that INTn has gone high and we will get an edge when a new event occurs. Tested on espressobin board. Fixes: dc30c35be720 ("net: dsa: mv88e6xxx: Implement interrupt support.") Signed-off-by: John David Anglin <dave.anglin@bell.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 8dca2c949e73..12fd7ce3f1ff 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -261,6 +261,7 @@ static irqreturn_t mv88e6xxx_g1_irq_thread_work(struct mv88e6xxx_chip *chip)
unsigned int sub_irq;
unsigned int n;
u16 reg;
+ u16 ctl1;
int err;
@@ -270,13 +271,28 @@ static irqreturn_t mv88e6xxx_g1_irq_thread_work(struct mv88e6xxx_chip *chip)
if (err)
goto out;
- for (n = 0; n < chip->g1_irq.nirqs; ++n) {
- if (reg & (1 << n)) {
- sub_irq = irq_find_mapping(chip->g1_irq.domain, n);
- handle_nested_irq(sub_irq);
- ++nhandled;
+ do {
+ for (n = 0; n < chip->g1_irq.nirqs; ++n) {
+ if (reg & (1 << n)) {
+ sub_irq = irq_find_mapping(chip->g1_irq.domain,
+ n);
+ handle_nested_irq(sub_irq);
+ ++nhandled;
+ }
- }
+ mutex_lock(&chip->reg_lock);
+ err = mv88e6xxx_g1_read(chip, MV88E6XXX_G1_CTL1, &ctl1);
+ if (err)
+ goto unlock;
+ err = mv88e6xxx_g1_read(chip, MV88E6XXX_G1_STS, &reg);
+ mutex_unlock(&chip->reg_lock);
+ if (err)
+ goto out;
+ ctl1 &= GENMASK(chip->g1_irq.nirqs, 0);
+ } while (reg & ctl1);
return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);