The patch titled gpio: timbgpio: use a copy of the IER register to avoid it being trashed has been added to the -mm tree. Its filename is gpio-timbgpio-use-a-copy-of-the-ier-register-to-avoid-it-being-trashed.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: gpio: timbgpio: use a copy of the IER register to avoid it being trashed From: Tomas Hallenberg <tomas.hallenberg@xxxxxxxxxxxxxx> Some versions of the hardware can trash the IER register if simultaneous interrupts occur. This patch works around it by using a local copy of the register and restoring it after every interrupt. Signed-off-by: Tomas Hallenberg <tomas.hallenberg@xxxxxxxxxxxxxx> Acked-by: Richard Röjfors <richard.rojfors@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/gpio/timbgpio.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff -puN drivers/gpio/timbgpio.c~gpio-timbgpio-use-a-copy-of-the-ier-register-to-avoid-it-being-trashed drivers/gpio/timbgpio.c --- a/drivers/gpio/timbgpio.c~gpio-timbgpio-use-a-copy-of-the-ier-register-to-avoid-it-being-trashed +++ a/drivers/gpio/timbgpio.c @@ -47,6 +47,7 @@ struct timbgpio { spinlock_t lock; /* mutual exclusion */ struct gpio_chip gpio; int irq_base; + unsigned long last_ier; }; static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index, @@ -112,16 +113,24 @@ static void timbgpio_irq_disable(unsigne { struct timbgpio *tgpio = get_irq_chip_data(irq); int offset = irq - tgpio->irq_base; + unsigned long flags; - timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 0); + spin_lock_irqsave(&tgpio->lock, flags); + tgpio->last_ier &= ~(1 << offset); + iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER); + spin_unlock_irqrestore(&tgpio->lock, flags); } static void timbgpio_irq_enable(unsigned irq) { struct timbgpio *tgpio = get_irq_chip_data(irq); int offset = irq - tgpio->irq_base; + unsigned long flags; - timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 1); + spin_lock_irqsave(&tgpio->lock, flags); + tgpio->last_ier |= 1 << offset; + iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER); + spin_unlock_irqrestore(&tgpio->lock, flags); } static int timbgpio_irq_type(unsigned irq, unsigned trigger) @@ -194,8 +203,16 @@ static void timbgpio_irq(unsigned int ir ipr = ioread32(tgpio->membase + TGPIO_IPR); iowrite32(ipr, tgpio->membase + TGPIO_ICR); + /* + * Some versions of the hardware trash the IER register if more than + * one interrupt is received simultaneously. + */ + iowrite32(0, tgpio->membase + TGPIO_IER); + for_each_set_bit(offset, &ipr, tgpio->gpio.ngpio) generic_handle_irq(timbgpio_to_irq(&tgpio->gpio, offset)); + + iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER); } static struct irq_chip timbgpio_irqchip = { _ Patches currently in -mm which might be from tomas.hallenberg@xxxxxxxxxxxxxx are gpio-timbgpio-use-a-copy-of-the-ier-register-to-avoid-it-being-trashed.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html