[v1,2/8] pinctrl: lynxpoint: Use raw_spinlock for locking
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Message ID 20191106144829.32275-3-andriy.shevchenko@linux.intel.com
State New
Headers show
Series
  • pinctrl: intel: Move Lynxpoint to pin control umbrella
Related show

Commit Message

andriy.shevchenko@linux.intel.com Nov. 6, 2019, 2:48 p.m. UTC
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.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/pinctrl/intel/pinctrl-lynxpoint.c | 28 +++++++++++------------
 1 file changed, 14 insertions(+), 14 deletions(-)

Patch
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diff --git a/drivers/pinctrl/intel/pinctrl-lynxpoint.c b/drivers/pinctrl/intel/pinctrl-lynxpoint.c
index e9e47c0d5be7..6467095523cc 100644
--- a/drivers/pinctrl/intel/pinctrl-lynxpoint.c
+++ b/drivers/pinctrl/intel/pinctrl-lynxpoint.c
@@ -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 */
@@ -164,7 +164,7 @@  static int lp_irq_type(struct irq_data *d, unsigned type)
 		value |= TRIG_SEL_BIT | INT_INV_BIT;
 
 	outl(value, reg);
-	spin_unlock_irqrestore(&lg->lock, flags);
+	raw_spin_unlock_irqrestore(&lg->lock, flags);
 
 	return 0;
 }
@@ -181,14 +181,14 @@  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)
@@ -197,9 +197,9 @@  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;
 }
@@ -213,9 +213,9 @@  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;
 }
@@ -266,9 +266,9 @@  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)
@@ -279,9 +279,9 @@  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 = {
@@ -345,7 +345,7 @@  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);