diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch b/target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch new file mode 100644 index 0000000..d912ba9 --- /dev/null +++ b/target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch @@ -0,0 +1,37 @@ +From 9dabf31b13de7de5742e3f13c0b38fff460b552b Mon Sep 17 00:00:00 2001 +From: Jonathan Bell <jonathan@raspberrypi.org> +Date: Tue, 30 Jun 2015 12:35:39 +0100 +Subject: [PATCH 148/203] pinctrl: bcm2835: Clear the event latch register when + disabling interrupts + +It's possible to hit a race condition if interrupts are generated on a GPIO +pin when the IRQ line in question is being disabled. + +If the interrupt is freed, bcm2835_gpio_irq_disable() is called which +disables the event generation sources (edge, level). If an event occurred +between the last disabling of hard IRQs and the write to the event +source registers, a bit would be set in the GPIO event detect register +(GPEDSn) which goes unacknowledged by bcm2835_gpio_irq_handler() +so Linux complains loudly. + +There is no per-GPIO mask register, so when disabling GPIO interrupts +write 1 to the relevant bit in GPEDSn to clear out any stale events. + +Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org> +Acked-by: Stephen Warren <swarren@wwwdotorg.org> +Signed-off-by: Linus Walleij <linus.walleij@linaro.org> +--- + drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 ++ + 1 file changed, 2 insertions(+) + +--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c ++++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c +@@ -503,6 +503,8 @@ static void bcm2835_gpio_irq_disable(str + + spin_lock_irqsave(&pc->irq_lock[bank], flags); + bcm2835_gpio_irq_config(pc, gpio, false); ++ /* Clear events that were latched prior to clearing event sources */ ++ bcm2835_gpio_set_bit(pc, GPEDS0, gpio); + clear_bit(offset, &pc->enabled_irq_map[bank]); + spin_unlock_irqrestore(&pc->irq_lock[bank], flags); + } |