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Subject[PATCH RT 01/31] gpio: omap: use raw locks for locking
3.10.70-rt75-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 | 70 ++++++++++++++++++++++++------------------------
1 file changed, 35 insertions(+), 35 deletions(-)

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 54052125859a..0fb30e1d1cff 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -59,7 +59,7 @@ struct gpio_bank {
u32 saved_datain;
u32 level_mask;
u32 toggle_mask;
- spinlock_t lock;
+ raw_spinlock_t lock;
struct gpio_chip chip;
struct clk *dbck;
u32 mod_usage;
@@ -503,19 +503,19 @@ 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);
offset = GPIO_INDEX(bank, gpio);
retval = _set_gpio_triggering(bank, offset, type);
if (!LINE_USED(bank->mod_usage, offset)) {
_enable_gpio_module(bank, offset);
_set_gpio_direction(bank, offset, 1);
} else if (!gpio_is_input(bank, 1 << offset)) {
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);
return -EINVAL;
}

bank->irq_usage |= 1 << GPIO_INDEX(bank, gpio);
- 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);
@@ -632,14 +632,14 @@ 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->context.wake_en |= gpio_bit;
else
bank->context.wake_en &= ~gpio_bit;

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

return 0;
}
@@ -674,7 +674,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
if (!BANK_USED(bank))
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(). Only do this if the IRQ line has
* not already been requested.
@@ -684,7 +684,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
_enable_gpio_module(bank, offset);
}
bank->mod_usage |= 1 << offset;
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -694,11 +694,11 @@ 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);
bank->mod_usage &= ~(1 << offset);
_disable_gpio_module(bank, 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,
@@ -796,11 +796,11 @@ static void gpio_irq_shutdown(struct irq_data *d)
unsigned long flags;
unsigned offset = GPIO_INDEX(bank, gpio);

- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);
bank->irq_usage &= ~(1 << offset);
_disable_gpio_module(bank, offset);
_reset_gpio(bank, gpio);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

/*
* If this is the last IRQ to be freed in the bank,
@@ -824,10 +824,10 @@ static void gpio_mask_irq(struct irq_data *d)
unsigned int gpio = irq_to_gpio(bank, d->hwirq);
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)
@@ -838,7 +838,7 @@ 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);

@@ -850,7 +850,7 @@ 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 = {
@@ -873,9 +873,9 @@ 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);
__raw_writel(0xffff & ~bank->context.wake_en, mask_reg);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -888,9 +888,9 @@ 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->context.wake_en, mask_reg);
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);

return 0;
}
@@ -933,9 +933,9 @@ 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;
}

@@ -960,7 +960,7 @@ static int gpio_output(struct gpio_chip *chip, unsigned offset, int value)
int retval = 0;

bank = container_of(chip, struct gpio_bank, chip);
- spin_lock_irqsave(&bank->lock, flags);
+ raw_spin_lock_irqsave(&bank->lock, flags);

if (LINE_USED(bank->irq_usage, offset)) {
retval = -EINVAL;
@@ -971,7 +971,7 @@ static int gpio_output(struct gpio_chip *chip, unsigned offset, int value)
_set_gpio_direction(bank, offset, 0);

exit:
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);
return retval;
}

@@ -983,9 +983,9 @@ static int gpio_debounce(struct gpio_chip *chip, unsigned offset,

bank = container_of(chip, struct gpio_bank, chip);

- 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;
}
@@ -996,9 +996,9 @@ 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);
}

/*---------------------------------------------------------------------*/
@@ -1210,7 +1210,7 @@ static int 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);
@@ -1267,7 +1267,7 @@ 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.
@@ -1320,7 +1320,7 @@ 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;
}
@@ -1335,7 +1335,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
unsigned long flags;
int c;

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

/*
* On the first resume during the probe, the context has not
@@ -1371,14 +1371,14 @@ static int omap_gpio_runtime_resume(struct device *dev)
if (c != bank->context_loss_count) {
omap_gpio_restore_context(bank);
} else {
- spin_unlock_irqrestore(&bank->lock, flags);
+ raw_spin_unlock_irqrestore(&bank->lock, flags);
return 0;
}
}
}

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

@@ -1433,7 +1433,7 @@ 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



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