[PATCH RT 01/27] gpio: omap: use raw locks for locking

From: Steven Rostedt
Date: Fri Mar 13 2015 - 11:18:13 EST

Next message: Steven Rostedt: "[PATCH RT 04/27] rtmutex: Simplify and document try_to_take_rtmutex()"
Previous message: Steven Rostedt: "[PATCH RT 26/31] lockdep: selftest: fix warnings due to missing PREEMPT_RT conditionals"
In reply to: Steven Rostedt: "[PATCH RT 00/27] Linux 3.4.106-rt132-rc1"
Next in thread: Steven Rostedt: "[PATCH RT 04/27] rtmutex: Simplify and document try_to_take_rtmutex()"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

3.4.106-rt132-rc1 stable review patch.
If anyone has any objections, please let me know.

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

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
drivers/gpio/gpio-omap.c | 76 ++++++++++++++++++++++++------------------------
1 file changed, 38 insertions(+), 38 deletions(-)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 4461540653a8..58ba0595c9a2 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -67,7 +67,7 @@ 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;
@@ -395,9 +395,9 @@ static int gpio_irq_type(struct irq_data *d, unsigned type)
(type & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH)))
return -EINVAL;

- 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);
@@ -514,14 +514,14 @@ 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;

__raw_writel(bank->suspend_wakeup, bank->base + bank->regs->wkup_en);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -555,7 +555,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
if (!bank->mod_usage)
pm_runtime_get_sync(bank->dev);

- 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().
*/
@@ -581,7 +581,7 @@ 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;
}
@@ -592,7 +592,7 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
void __iomem *base = bank->base;
unsigned long flags;

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);

if (bank->regs->wkup_en) {
/* Disable wake-up during idle for dynamic tick */
@@ -615,7 +615,7 @@ 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);

/*
* If this is the last gpio to be freed in the bank,
@@ -720,9 +720,9 @@ static void gpio_irq_shutdown(struct irq_data *d)
unsigned int gpio = irq_to_gpio(bank, d->irq);
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)
@@ -739,10 +739,10 @@ static void gpio_mask_irq(struct irq_data *d)
unsigned int gpio = irq_to_gpio(bank, d->irq);
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)
@@ -753,7 +753,7 @@ 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);

@@ -765,7 +765,7 @@ 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 = {
@@ -788,10 +788,10 @@ 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;
}
@@ -804,9 +804,9 @@ 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;
}
@@ -849,9 +849,9 @@ 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;
}

@@ -882,10 +882,10 @@ 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;
}

@@ -903,9 +903,9 @@ 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;
}
@@ -916,9 +916,9 @@ 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)
@@ -1109,7 +1109,7 @@ 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);
@@ -1169,11 +1169,11 @@ static int omap_gpio_suspend(struct device *dev)

wakeup_enable = bank->base + bank->regs->wkup_en;

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);
bank->saved_wakeup = __raw_readl(wakeup_enable);
_gpio_rmw(base, bank->regs->wkup_en, 0xffffffff, 0);
_gpio_rmw(base, bank->regs->wkup_en, bank->suspend_wakeup, 1);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -1191,10 +1191,10 @@ static int omap_gpio_resume(struct device *dev)
if (!bank->regs->wkup_en || !bank->saved_wakeup)
return 0;

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);
_gpio_rmw(base, bank->regs->wkup_en, 0xffffffff, 0);
_gpio_rmw(base, bank->regs->wkup_en, bank->saved_wakeup, 1);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -1211,7 +1211,7 @@ static int omap_gpio_runtime_suspend(struct device *dev)
unsigned long flags;
u32 wake_low, wake_hi;

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);

/*
* Only edges can generate a wakeup event to the PRCM.
@@ -1263,7 +1263,7 @@ update_gpio_context_count:
bank->get_context_loss_count(bank->dev);

_gpio_dbck_disable(bank);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -1276,7 +1276,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
u32 l = 0, gen, gen0, gen1;
unsigned long flags;

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);
_gpio_dbck_enable(bank);

/*
@@ -1291,7 +1291,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
bank->base + bank->regs->risingdetect);

if (!bank->workaround_enabled) {
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);
return 0;
}

@@ -1302,7 +1302,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
!context_lost_cnt_after) {
omap_gpio_restore_context(bank);
} else {
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);
return 0;
}
}
@@ -1361,7 +1361,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
}

bank->workaround_enabled = false;
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
--
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Steven Rostedt: "[PATCH RT 04/27] rtmutex: Simplify and document try_to_take_rtmutex()"
Previous message: Steven Rostedt: "[PATCH RT 26/31] lockdep: selftest: fix warnings due to missing PREEMPT_RT conditionals"
In reply to: Steven Rostedt: "[PATCH RT 00/27] Linux 3.4.106-rt132-rc1"
Next in thread: Steven Rostedt: "[PATCH RT 04/27] rtmutex: Simplify and document try_to_take_rtmutex()"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]