Commit b2e05d63 authored by Andy Shevchenko's avatar Andy Shevchenko
Browse files

pinctrl: lynxpoint: Use raw_spinlock for locking 



The Intel Lynxpoint pinctrl driver implements irqchip callbacks which are
called with desc->lock raw_spinlock held. In mainline this is fine because
spinlock resolves to raw_spinlock. However, running the same code in -rt
we will get a BUG() asserted.

This is because in -rt spinlocks are preemptible so taking the driver
private spinlock in irqchip callbacks causes might_sleep() to trigger.

In order to keep -rt happy but at the same time make sure that register
accesses get serialized, convert the driver to use raw_spinlock instead.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent eb83479e

drivers/pinctrl/intel/pinctrl-lynxpoint.c

+14 −14
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ 
struct lp_gpio {

	struct gpio_chip	chip;

	struct platform_device	*pdev;

	spinlock_t		lock;

	raw_spinlock_t		lock;

	unsigned long		reg_base;

};
@@ -144,7 +144,7 @@ static int lp_irq_type(struct irq_data *d, unsigned type) 
	if (hwirq >= lg->chip.ngpio)

		return -EINVAL;



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);

	value = inl(reg);



	/* set both TRIG_SEL and INV bits to 0 for rising edge */
@@ -170,7 +170,7 @@ static int lp_irq_type(struct irq_data *d, unsigned type) 
	else if (type & IRQ_TYPE_LEVEL_MASK)

		irq_set_handler_locked(d, handle_level_irq);



	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);



	return 0;

}
@@ -187,14 +187,14 @@ static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);

	unsigned long flags;



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);



	if (value)

		outl(inl(reg) | OUT_LVL_BIT, reg);

	else

		outl(inl(reg) & ~OUT_LVL_BIT, reg);



	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);

}



static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
@@ -203,9 +203,9 @@ static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset) 
	unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);

	unsigned long flags;



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);

	outl(inl(reg) | DIR_BIT, reg);

	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);



	return 0;

}
@@ -219,9 +219,9 @@ static int lp_gpio_direction_output(struct gpio_chip *chip, 


	lp_gpio_set(chip, offset, value);



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);

	outl(inl(reg) & ~DIR_BIT, reg);

	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);



	return 0;

}
@@ -272,9 +272,9 @@ static void lp_irq_enable(struct irq_data *d) 
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);

	unsigned long flags;



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);

	outl(inl(reg) | BIT(hwirq % 32), reg);

	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);

}



static void lp_irq_disable(struct irq_data *d)
@@ -285,9 +285,9 @@ static void lp_irq_disable(struct irq_data *d) 
	unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);

	unsigned long flags;



	spin_lock_irqsave(&lg->lock, flags);

	raw_spin_lock_irqsave(&lg->lock, flags);

	outl(inl(reg) & ~BIT(hwirq % 32), reg);

	spin_unlock_irqrestore(&lg->lock, flags);

	raw_spin_unlock_irqrestore(&lg->lock, flags);

}



static struct irq_chip lp_irqchip = {
@@ -351,7 +351,7 @@ static int lp_gpio_probe(struct platform_device *pdev) 
		return -EBUSY;

	}



	spin_lock_init(&lg->lock);

	raw_spin_lock_init(&lg->lock);



	gc = &lg->chip;

	gc->label = dev_name(dev);

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