| Message ID | 9b15e28c4aeeade4b44e9a2bb06c12ded5d0990b.1490135047.git.julia@ni.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Mar 21, 2017 at 05:43:08PM -0500, Julia Cartwright wrote: >The 104-idio-16 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> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> >--- >New patch as of v2 of series. > > drivers/gpio/gpio-104-idio-16.c | 24 ++++++++++++------------ > 1 file changed, 12 insertions(+), 12 deletions(-) > >diff --git a/drivers/gpio/gpio-104-idio-16.c b/drivers/gpio/gpio-104-idio-16.c >index 7053cf736648..5281e1cedb01 100644 >--- a/drivers/gpio/gpio-104-idio-16.c >+++ b/drivers/gpio/gpio-104-idio-16.c >@@ -50,7 +50,7 @@ MODULE_PARM_DESC(irq, "ACCES 104-IDIO-16 interrupt line numbers"); > */ > struct idio_16_gpio { > struct gpio_chip chip; >- spinlock_t lock; >+ raw_spinlock_t lock; > unsigned long irq_mask; > unsigned base; > unsigned out_state; >@@ -99,7 +99,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value) > if (offset > 15) > return; > >- spin_lock_irqsave(&idio16gpio->lock, flags); >+ raw_spin_lock_irqsave(&idio16gpio->lock, flags); > > if (value) > idio16gpio->out_state |= mask; >@@ -111,7 +111,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value) > else > outb(idio16gpio->out_state, idio16gpio->base); > >- spin_unlock_irqrestore(&idio16gpio->lock, flags); >+ raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); > } > > static void idio_16_gpio_set_multiple(struct gpio_chip *chip, >@@ -120,7 +120,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip, > struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip); > unsigned long flags; > >- spin_lock_irqsave(&idio16gpio->lock, flags); >+ raw_spin_lock_irqsave(&idio16gpio->lock, flags); > > idio16gpio->out_state &= ~*mask; > idio16gpio->out_state |= *mask & *bits; >@@ -130,7 +130,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip, > if ((*mask >> 8) & 0xFF) > outb(idio16gpio->out_state >> 8, idio16gpio->base + 4); > >- spin_unlock_irqrestore(&idio16gpio->lock, flags); >+ raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); > } > > static void idio_16_irq_ack(struct irq_data *data) >@@ -147,11 +147,11 @@ static void idio_16_irq_mask(struct irq_data *data) > idio16gpio->irq_mask &= ~mask; > > if (!idio16gpio->irq_mask) { >- spin_lock_irqsave(&idio16gpio->lock, flags); >+ raw_spin_lock_irqsave(&idio16gpio->lock, flags); > > outb(0, idio16gpio->base + 2); > >- spin_unlock_irqrestore(&idio16gpio->lock, flags); >+ raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); > } > } > >@@ -166,11 +166,11 @@ static void idio_16_irq_unmask(struct irq_data *data) > idio16gpio->irq_mask |= mask; > > if (!prev_irq_mask) { >- spin_lock_irqsave(&idio16gpio->lock, flags); >+ raw_spin_lock_irqsave(&idio16gpio->lock, flags); > > inb(idio16gpio->base + 2); > >- spin_unlock_irqrestore(&idio16gpio->lock, flags); >+ raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); > } > } > >@@ -201,11 +201,11 @@ static irqreturn_t idio_16_irq_handler(int irq, void *dev_id) > for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio) > generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio)); > >- spin_lock(&idio16gpio->lock); >+ raw_spin_lock(&idio16gpio->lock); > > outb(0, idio16gpio->base + 1); > >- spin_unlock(&idio16gpio->lock); >+ raw_spin_unlock(&idio16gpio->lock); > > return IRQ_HANDLED; > } >@@ -249,7 +249,7 @@ static int idio_16_probe(struct device *dev, unsigned int id) > idio16gpio->base = base[id]; > idio16gpio->out_state = 0xFFFF; > >- spin_lock_init(&idio16gpio->lock); >+ raw_spin_lock_init(&idio16gpio->lock); > > err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio); > if (err) { >-- >2.12.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 21, 2017 at 11:43 PM, Julia Cartwright <julia@ni.com> wrote: > The 104-idio-16 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> > --- > New patch as of v2 of series. Patch applied to the GPIO tree with William's ACK. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/gpio/gpio-104-idio-16.c b/drivers/gpio/gpio-104-idio-16.c index 7053cf736648..5281e1cedb01 100644 --- a/drivers/gpio/gpio-104-idio-16.c +++ b/drivers/gpio/gpio-104-idio-16.c @@ -50,7 +50,7 @@ MODULE_PARM_DESC(irq, "ACCES 104-IDIO-16 interrupt line numbers"); */ struct idio_16_gpio { struct gpio_chip chip; - spinlock_t lock; + raw_spinlock_t lock; unsigned long irq_mask; unsigned base; unsigned out_state; @@ -99,7 +99,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value) if (offset > 15) return; - spin_lock_irqsave(&idio16gpio->lock, flags); + raw_spin_lock_irqsave(&idio16gpio->lock, flags); if (value) idio16gpio->out_state |= mask; @@ -111,7 +111,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value) else outb(idio16gpio->out_state, idio16gpio->base); - spin_unlock_irqrestore(&idio16gpio->lock, flags); + raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); } static void idio_16_gpio_set_multiple(struct gpio_chip *chip, @@ -120,7 +120,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip, struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip); unsigned long flags; - spin_lock_irqsave(&idio16gpio->lock, flags); + raw_spin_lock_irqsave(&idio16gpio->lock, flags); idio16gpio->out_state &= ~*mask; idio16gpio->out_state |= *mask & *bits; @@ -130,7 +130,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip, if ((*mask >> 8) & 0xFF) outb(idio16gpio->out_state >> 8, idio16gpio->base + 4); - spin_unlock_irqrestore(&idio16gpio->lock, flags); + raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); } static void idio_16_irq_ack(struct irq_data *data) @@ -147,11 +147,11 @@ static void idio_16_irq_mask(struct irq_data *data) idio16gpio->irq_mask &= ~mask; if (!idio16gpio->irq_mask) { - spin_lock_irqsave(&idio16gpio->lock, flags); + raw_spin_lock_irqsave(&idio16gpio->lock, flags); outb(0, idio16gpio->base + 2); - spin_unlock_irqrestore(&idio16gpio->lock, flags); + raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); } } @@ -166,11 +166,11 @@ static void idio_16_irq_unmask(struct irq_data *data) idio16gpio->irq_mask |= mask; if (!prev_irq_mask) { - spin_lock_irqsave(&idio16gpio->lock, flags); + raw_spin_lock_irqsave(&idio16gpio->lock, flags); inb(idio16gpio->base + 2); - spin_unlock_irqrestore(&idio16gpio->lock, flags); + raw_spin_unlock_irqrestore(&idio16gpio->lock, flags); } } @@ -201,11 +201,11 @@ static irqreturn_t idio_16_irq_handler(int irq, void *dev_id) for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio) generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio)); - spin_lock(&idio16gpio->lock); + raw_spin_lock(&idio16gpio->lock); outb(0, idio16gpio->base + 1); - spin_unlock(&idio16gpio->lock); + raw_spin_unlock(&idio16gpio->lock); return IRQ_HANDLED; } @@ -249,7 +249,7 @@ static int idio_16_probe(struct device *dev, unsigned int id) idio16gpio->base = base[id]; idio16gpio->out_state = 0xFFFF; - spin_lock_init(&idio16gpio->lock); + raw_spin_lock_init(&idio16gpio->lock); err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio); if (err) {
The 104-idio-16 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> --- New patch as of v2 of series. drivers/gpio/gpio-104-idio-16.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)