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gpio: pl061: make use of raw_spinlock variants 

The pl061 gpio driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Julia Cartwright 2017-03-09 10:21:56 -06:00 committed by Linus Walleij
parent f9c56536d5
commit 99b9b45de8
1 changed files with 14 additions and 14 deletions
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28
drivers/gpio/gpio-pl061.c
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@ -50,7 +50,7 @@ struct pl061_context_save_regs {
#endif
struct pl061 {
spinlock_t lock;
raw_spinlock_t lock;
void __iomem *base;
struct gpio_chip gc;
@ -74,11 +74,11 @@ static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
unsigned long flags;
unsigned char gpiodir;
spin_lock_irqsave(&pl061->lock, flags);
raw_spin_lock_irqsave(&pl061->lock, flags);
gpiodir = readb(pl061->base + GPIODIR);
gpiodir &= ~(BIT(offset));
writeb(gpiodir, pl061->base + GPIODIR);
spin_unlock_irqrestore(&pl061->lock, flags);
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
@ -90,7 +90,7 @@ static int pl061_direction_output(struct gpio_chip *gc, unsigned offset,
unsigned long flags;
unsigned char gpiodir;
spin_lock_irqsave(&pl061->lock, flags);
raw_spin_lock_irqsave(&pl061->lock, flags);
writeb(!!value << offset, pl061->base + (BIT(offset + 2)));
gpiodir = readb(pl061->base + GPIODIR);
gpiodir |= BIT(offset);
@ -101,7 +101,7 @@ static int pl061_direction_output(struct gpio_chip *gc, unsigned offset,
* a gpio pin before configuring it in OUT mode.
*/
writeb(!!value << offset, pl061->base + (BIT(offset + 2)));
spin_unlock_irqrestore(&pl061->lock, flags);
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
@ -143,7 +143,7 @@ static int pl061_irq_type(struct irq_data *d, unsigned trigger)
}
spin_lock_irqsave(&pl061->lock, flags);
raw_spin_lock_irqsave(&pl061->lock, flags);
gpioiev = readb(pl061->base + GPIOIEV);
gpiois = readb(pl061->base + GPIOIS);
@ -203,7 +203,7 @@ static int pl061_irq_type(struct irq_data *d, unsigned trigger)
writeb(gpioibe, pl061->base + GPIOIBE);
writeb(gpioiev, pl061->base + GPIOIEV);
spin_unlock_irqrestore(&pl061->lock, flags);
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
@ -235,10 +235,10 @@ static void pl061_irq_mask(struct irq_data *d)
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
u8 gpioie;
spin_lock(&pl061->lock);
raw_spin_lock(&pl061->lock);
gpioie = readb(pl061->base + GPIOIE) & ~mask;
writeb(gpioie, pl061->base + GPIOIE);
spin_unlock(&pl061->lock);
raw_spin_unlock(&pl061->lock);
}
static void pl061_irq_unmask(struct irq_data *d)
@ -248,10 +248,10 @@ static void pl061_irq_unmask(struct irq_data *d)
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
u8 gpioie;
spin_lock(&pl061->lock);
raw_spin_lock(&pl061->lock);
gpioie = readb(pl061->base + GPIOIE) | mask;
writeb(gpioie, pl061->base + GPIOIE);
spin_unlock(&pl061->lock);
raw_spin_unlock(&pl061->lock);
}
/**
@ -268,9 +268,9 @@ static void pl061_irq_ack(struct irq_data *d)
struct pl061 *pl061 = gpiochip_get_data(gc);
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
spin_lock(&pl061->lock);
raw_spin_lock(&pl061->lock);
writeb(mask, pl061->base + GPIOIC);
spin_unlock(&pl061->lock);
raw_spin_unlock(&pl061->lock);
}
static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
@ -304,7 +304,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
if (IS_ERR(pl061->base))
return PTR_ERR(pl061->base);
spin_lock_init(&pl061->lock);
raw_spin_lock_init(&pl061->lock);
if (of_property_read_bool(dev->of_node, "gpio-ranges")) {
pl061->gc.request = gpiochip_generic_request;
pl061->gc.free = gpiochip_generic_free;