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Subject[PATCH 4/7] gpio: omap: protect regs access in omap_gpio_irq_handler
Date
The access to HW registers has to be be protected in
omap_gpio_irq_handler(), as it may race with code executed on
another CPUs.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
---
drivers/gpio/gpio-omap.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 9ed5a67..1f02acd 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -718,6 +718,7 @@ static void omap_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
int unmasked = 0;
struct irq_chip *irqchip = irq_desc_get_chip(desc);
struct gpio_chip *chip = irq_desc_get_handler_data(desc);
+ unsigned long lock_flags;

chained_irq_enter(irqchip, desc);

@@ -732,6 +733,8 @@ static void omap_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
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;

@@ -745,6 +748,8 @@ static void omap_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
omap_clear_gpio_irqbank(bank, isr_saved & ~level_mask);
omap_enable_gpio_irqbank(bank, isr_saved & ~level_mask);

+ raw_spin_unlock_irqrestore(&bank->lock, lock_flags);
+
/* if there is only edge sensitive GPIO pin interrupts
configured, we could unmask GPIO bank interrupt immediately */
if (!level_mask && !unmasked) {
@@ -759,6 +764,7 @@ static void omap_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
bit = __ffs(isr);
isr &= ~(BIT(bit));

+ raw_spin_lock_irqsave(&bank->lock, lock_flags);
/*
* Some chips can't respond to both rising and falling
* at the same time. If this irq was requested with
@@ -769,6 +775,8 @@ static void omap_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
if (bank->toggle_mask & (BIT(bit)))
omap_toggle_gpio_edge_triggering(bank, bit);

+ raw_spin_unlock_irqrestore(&bank->lock, lock_flags);
+
generic_handle_irq(irq_find_mapping(bank->chip.irqdomain,
bit));
}
--
2.5.0


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