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Subject[RESEND PATCH] gpio: omap: Fix lost edge interrupts
Date
Now acking of edge irqs happens the following way:
- omap_gpio_irq_handler
- "isr" = read irq status
- omap_clear_gpio_irqbank(bank, isr_saved & ~level_mask);
^ clear edge status, so irq can be accepted
- loop while "isr"
generic_handle_irq()
- handle_edge_irq()
- desc->irq_data.chip->irq_ack(&desc->irq_data);
- omap_gpio_ack_irq()
it might be that at this moment edge IRQ was triggered again and it will be
cleared and IRQ will be lost.

Use handle_simple_irq and clear edge interrupts early without disabling them in
omap_gpio_irq_handler to avoid loosing interrupts.

[1] https://marc.info/?l=linux-omap&m=149004465313534&w=2
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
Resend with proper cc list.

drivers/gpio/gpio-omap.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index dbf869f..0c80052 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -518,7 +518,13 @@ static int omap_gpio_irq_type(struct irq_data *d, unsigned type)
if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
irq_set_handler_locked(d, handle_level_irq);
else if (type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
- irq_set_handler_locked(d, handle_edge_irq);
+ /*
+ * Edge IRQs are already cleared/acked in irq_handler and
+ * not need to be masked, as result handle_edge_irq()
+ * logic is excessed here and may cause lose of interrupts.
+ * So just use handle_simple_irq.
+ */
+ irq_set_handler_locked(d, handle_simple_irq);

return 0;

@@ -678,7 +684,7 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
static irqreturn_t omap_gpio_irq_handler(int irq, void *gpiobank)
{
void __iomem *isr_reg = NULL;
- u32 isr;
+ u32 enabled, isr, level_mask;
unsigned int bit;
struct gpio_bank *bank = gpiobank;
unsigned long wa_lock_flags;
@@ -691,23 +697,21 @@ static irqreturn_t omap_gpio_irq_handler(int irq, void *gpiobank)
pm_runtime_get_sync(bank->chip.parent);

while (1) {
- u32 isr_saved, level_mask = 0;
- u32 enabled;
-
raw_spin_lock_irqsave(&bank->lock, lock_flags);

enabled = omap_get_gpio_irqbank_mask(bank);
- isr_saved = isr = readl_relaxed(isr_reg) & enabled;
+ isr = readl_relaxed(isr_reg) & enabled;

if (bank->level_mask)
level_mask = bank->level_mask & enabled;
+ else
+ level_mask = 0;

/* clear edge sensitive interrupts before handler(s) are
called so that we don't miss any interrupt occurred while
executing them */
- omap_disable_gpio_irqbank(bank, isr_saved & ~level_mask);
- omap_clear_gpio_irqbank(bank, isr_saved & ~level_mask);
- omap_enable_gpio_irqbank(bank, isr_saved & ~level_mask);
+ if (isr & ~level_mask)
+ omap_clear_gpio_irqbank(bank, isr & ~level_mask);

raw_spin_unlock_irqrestore(&bank->lock, lock_flags);

--
2.10.1
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