| Message ID | 20171024195451.30535-4-opendmb@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 24, 2017 at 9:54 PM, Doug Berger <opendmb@gmail.com> wrote: > The basic memory-mapped GPIO controller lock must be released > before calling the registered GPIO interrupt handlers to allow > the interrupt handlers to access the hardware. > > Examples of why a GPIO interrupt handler might want to access > the GPIO hardware include an interrupt that is configured to > trigger on rising and falling edges that needs to read the > current level of the input to know how to respond, or an > interrupt that causes a change in a GPIO output in the same > bank. If the lock is not released before enterring the handler > the hardware accesses will deadlock when they attempt to grab > the lock. > > Since the lock is only needed to protect the calculation of > unmasked pending interrupts create a dedicated function to > perform this and hide the complexity. > > Fixes: 19a7b6940b78 ("gpio: brcmstb: Add interrupt and wakeup source support") > Signed-off-by: Doug Berger <opendmb@gmail.com> > Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> > Acked-by: Gregory Fong <gregory.0xf0@gmail.com> Patch applied. Yours, Linus Walleij
diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c index 2031b73e066c..fd8c0412f8af 100644 --- a/drivers/gpio/gpio-brcmstb.c +++ b/drivers/gpio/gpio-brcmstb.c @@ -63,6 +63,21 @@ brcmstb_gpio_gc_to_priv(struct gpio_chip *gc) return bank->parent_priv; } +static unsigned long +brcmstb_gpio_get_active_irqs(struct brcmstb_gpio_bank *bank) +{ + void __iomem *reg_base = bank->parent_priv->reg_base; + unsigned long status; + unsigned long flags; + + spin_lock_irqsave(&bank->gc.bgpio_lock, flags); + status = bank->gc.read_reg(reg_base + GIO_STAT(bank->id)) & + bank->gc.read_reg(reg_base + GIO_MASK(bank->id)); + spin_unlock_irqrestore(&bank->gc.bgpio_lock, flags); + + return status; +} + static void brcmstb_gpio_set_imask(struct brcmstb_gpio_bank *bank, unsigned int offset, bool enable) { @@ -204,11 +219,8 @@ static void brcmstb_gpio_irq_bank_handler(struct brcmstb_gpio_bank *bank) struct irq_domain *irq_domain = bank->gc.irqdomain; void __iomem *reg_base = priv->reg_base; unsigned long status; - unsigned long flags; - spin_lock_irqsave(&bank->gc.bgpio_lock, flags); - while ((status = bank->gc.read_reg(reg_base + GIO_STAT(bank->id)) & - bank->gc.read_reg(reg_base + GIO_MASK(bank->id)))) { + while ((status = brcmstb_gpio_get_active_irqs(bank))) { int bit; for_each_set_bit(bit, &status, 32) { @@ -223,7 +235,6 @@ static void brcmstb_gpio_irq_bank_handler(struct brcmstb_gpio_bank *bank) generic_handle_irq(irq_find_mapping(irq_domain, bit)); } } - spin_unlock_irqrestore(&bank->gc.bgpio_lock, flags); } /* Each UPG GIO block has one IRQ for all banks */
The basic memory-mapped GPIO controller lock must be released before calling the registered GPIO interrupt handlers to allow the interrupt handlers to access the hardware. Examples of why a GPIO interrupt handler might want to access the GPIO hardware include an interrupt that is configured to trigger on rising and falling edges that needs to read the current level of the input to know how to respond, or an interrupt that causes a change in a GPIO output in the same bank. If the lock is not released before enterring the handler the hardware accesses will deadlock when they attempt to grab the lock. Since the lock is only needed to protect the calculation of unmasked pending interrupts create a dedicated function to perform this and hide the complexity. Fixes: 19a7b6940b78 ("gpio: brcmstb: Add interrupt and wakeup source support") Signed-off-by: Doug Berger <opendmb@gmail.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Gregory Fong <gregory.0xf0@gmail.com> --- drivers/gpio/gpio-brcmstb.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)