[PATCH RT 01/25] gpio: omap: use raw locks for locking

[Steven Rostedt <rostedt@goodmis.org>]

[-- Attachment #1: 0001-gpio-omap-use-raw-locks-for-locking.patch --]
[-- Type: text/plain, Size: 9103 bytes --]

3.2.68-rt99-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

This patch converts gpio_bank.lock from a spin_lock into a
raw_spin_lock. The call path is to access this lock is always under a
raw_spin_lock, for instance
- __setup_irq() holds &desc->lock with irq off
  + __irq_set_trigger()
   + omap_gpio_irq_type()

- handle_level_irq() (runs with irqs off therefore raw locks)
  + mask_ack_irq()
   + omap_gpio_mask_irq()

This fixes the obvious backtrace on -RT. However the locking vs context
is not and this is not limited to -RT:
- omap_gpio_irq_type() is called with IRQ off and has an conditional
  call to pm_runtime_get_sync() which may sleep. Either it may happen or
  it may not happen but pm_runtime_get_sync() should not be called with
  irqs off.

- omap_gpio_debounce() is holding the lock with IRQs off.
  + omap2_set_gpio_debounce()
   + clk_prepare_enable()
    + clk_prepare() this one might sleep.
  The number of users of gpiod_set_debounce() / gpio_set_debounce()
  looks low but still this is not good.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/gpio/gpio-omap.c | 64 ++++++++++++++++++++++++------------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index a6c10e849e61..e4d11e424b5b 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -46,7 +46,7 @@ struct gpio_bank {
 	u32 saved_risingdetect;
 	u32 level_mask;
 	u32 toggle_mask;
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	struct gpio_chip chip;
 	struct clk *dbck;
 	u32 mod_usage;
@@ -418,9 +418,9 @@ static int gpio_irq_type(struct irq_data *d, unsigned type)
 		return -EINVAL;
 
 	bank = irq_data_get_irq_chip_data(d);
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	retval = _set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), type);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
 		__irq_set_handler_locked(d->irq, handle_level_irq);
@@ -533,13 +533,13 @@ static int _set_gpio_wakeup(struct gpio_bank *bank, int gpio, int enable)
 		return -EINVAL;
 	}
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	if (enable)
 		bank->suspend_wakeup |= gpio_bit;
 	else
 		bank->suspend_wakeup &= ~gpio_bit;
 
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
 }
@@ -570,7 +570,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
 	struct gpio_bank *bank = container_of(chip, struct gpio_bank, chip);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 
 	/* Set trigger to none. You need to enable the desired trigger with
 	 * request_irq() or set_irq_type().
@@ -602,7 +602,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
 		}
 		bank->mod_usage |= 1 << offset;
 	}
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
 }
@@ -612,7 +612,7 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
 	struct gpio_bank *bank = container_of(chip, struct gpio_bank, chip);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 #ifdef CONFIG_ARCH_OMAP16XX
 	if (bank->method == METHOD_GPIO_1610) {
 		/* Disable wake-up during idle for dynamic tick */
@@ -651,7 +651,7 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
 		}
 	}
 	_reset_gpio(bank, bank->chip.base + offset);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 /*
@@ -751,9 +751,9 @@ static void gpio_irq_shutdown(struct irq_data *d)
 	struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	_reset_gpio(bank, gpio);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static void gpio_ack_irq(struct irq_data *d)
@@ -770,10 +770,10 @@ static void gpio_mask_irq(struct irq_data *d)
 	struct gpio_bank *bank = irq_data_get_irq_chip_data(d);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	_set_gpio_irqenable(bank, gpio, 0);
 	_set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), IRQ_TYPE_NONE);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static void gpio_unmask_irq(struct irq_data *d)
@@ -784,7 +784,7 @@ static void gpio_unmask_irq(struct irq_data *d)
 	u32 trigger = irqd_get_trigger_type(d);
 	unsigned long flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	if (trigger)
 		_set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), trigger);
 
@@ -796,7 +796,7 @@ static void gpio_unmask_irq(struct irq_data *d)
 	}
 
 	_set_gpio_irqenable(bank, gpio, 1);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static struct irq_chip gpio_irq_chip = {
@@ -827,10 +827,10 @@ static int omap_mpuio_suspend_noirq(struct device *dev)
 					OMAP_MPUIO_GPIO_MASKIT / bank->stride;
 	unsigned long		flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	bank->saved_wakeup = __raw_readl(mask_reg);
 	__raw_writel(0xffff & ~bank->suspend_wakeup, mask_reg);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
 }
@@ -843,9 +843,9 @@ static int omap_mpuio_resume_noirq(struct device *dev)
 					OMAP_MPUIO_GPIO_MASKIT / bank->stride;
 	unsigned long		flags;
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	__raw_writel(bank->saved_wakeup, mask_reg);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
 }
@@ -904,9 +904,9 @@ static int gpio_input(struct gpio_chip *chip, unsigned offset)
 	unsigned long flags;
 
 	bank = container_of(chip, struct gpio_bank, chip);
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	_set_gpio_direction(bank, offset, 1);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 	return 0;
 }
 
@@ -941,10 +941,10 @@ static int gpio_output(struct gpio_chip *chip, unsigned offset, int value)
 	unsigned long flags;
 
 	bank = container_of(chip, struct gpio_bank, chip);
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	bank->set_dataout(bank, offset, value);
 	_set_gpio_direction(bank, offset, 0);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 	return 0;
 }
 
@@ -962,9 +962,9 @@ static int gpio_debounce(struct gpio_chip *chip, unsigned offset,
 			dev_err(bank->dev, "Could not get gpio dbck\n");
 	}
 
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	_set_gpio_debounce(bank, offset, debounce);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
 }
@@ -975,9 +975,9 @@ static void gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 	unsigned long flags;
 
 	bank = container_of(chip, struct gpio_bank, chip);
-	spin_lock_irqsave(&bank->lock, flags);
+	raw_spin_lock_irqsave(&bank->lock, flags);
 	bank->set_dataout(bank, offset, value);
-	spin_unlock_irqrestore(&bank->lock, flags);
+	raw_spin_unlock_irqrestore(&bank->lock, flags);
 }
 
 static int gpio_2irq(struct gpio_chip *chip, unsigned offset)
@@ -1207,7 +1207,7 @@ static int __devinit omap_gpio_probe(struct platform_device *pdev)
 	else
 		bank->set_dataout = _set_gpio_dataout_mask;
 
-	spin_lock_init(&bank->lock);
+	raw_spin_lock_init(&bank->lock);
 
 	/* Static mapping, never released */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1276,11 +1276,11 @@ static int omap_gpio_suspend(void)
 			continue;
 		}
 
-		spin_lock_irqsave(&bank->lock, flags);
+		raw_spin_lock_irqsave(&bank->lock, flags);
 		bank->saved_wakeup = __raw_readl(wake_status);
 		__raw_writel(0xffffffff, wake_clear);
 		__raw_writel(bank->suspend_wakeup, wake_set);
-		spin_unlock_irqrestore(&bank->lock, flags);
+		raw_spin_unlock_irqrestore(&bank->lock, flags);
 	}
 
 	return 0;
@@ -1322,10 +1322,10 @@ static void omap_gpio_resume(void)
 			continue;
 		}
 
-		spin_lock_irqsave(&bank->lock, flags);
+		raw_spin_lock_irqsave(&bank->lock, flags);
 		__raw_writel(0xffffffff, wake_clear);
 		__raw_writel(bank->saved_wakeup, wake_set);
-		spin_unlock_irqrestore(&bank->lock, flags);
+		raw_spin_unlock_irqrestore(&bank->lock, flags);
 	}
 }
 
-- 
2.1.4